Final Design Report Rev 1 - Residential Wastewater Heat … · 2012-04-05 · Team Flüggen –...

Team Flüggen

Residential Wastewater Heat Recovery

Final Design Report

Memorial University of Newfoundland

Engineering 8936: Mechanical Project II

Course Instructor: Andy Fisher

Project Supervisor: Dr. Steve Bruneau

Team Members:

Steve Rumbolt – 200636090

Ben Reinhart – 200624435

Andrew McCabe – 200537488

Chris Dawe - 200421873

April 5th

, 2012

Team Flüggen – Final Report

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Table of Contents

1.0 Executive Summary .................................................................................................................................... 2

2.0 Project Scope ............................................................................................................................................... 3

3.0 Background Research ................................................................................................................................. 4

4.0 Concept Selection Process ........................................................................................................................ 6

5.0 Final Design Concept .................................................................................................................................. 8

6.0 Theoretical Calculations ......................................................................................................................... 11

7.0 Detailed Design ........................................................................................................................................ 18

8.0 Model Construction ................................................................................................................................. 21

9.0 Model Testing ........................................................................................................................................... 26

10.0 Energy Savings .......................................................................................................................................... 32

11.0 Environmental, Health, Safety, Risks and Sustainability .................................................................. 35

12.0 Design Review .......................................................................................................................................... 37

13.0 Design Recommendations...................................................................................................................... 38

14.0 Future Look Ahead .................................................................................................................................. 42

15.0 Conclusions ............................................................................................................................................... 44

16.0 References ................................................................................................................................................. 45

APPENDIX A- Project Schedule ............................................................................................................................ 46

APPENDIX B – Technical Drawing Packages ...................................................................................................... 47

APPENDIX C – Theoretical Calculations.............................................................................................................. 57

APPENDIX D – Design of Experiments ................................................................................................................ 66

APPENDIX E – Testing Results .............................................................................................................................. 69

APPENDIX F – Construction and Testing Pictures ............................................................................................ 95

APPENDIX G – Design Criteria Table ................................................................................................................... 98

APPENDIX H – Screening and Evaluation Matrices ........................................................................................ 101

APPENDIX I – Final Concept Sketches ............................................................................................................... 102


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1.0 Executive Summary

Through the course of our term 8 mechanical engineering project, we designed and tested a

grey water heat recovery device to salvage heat from wastewater typically wasted down the drain. This

project focused on showers, baths, and dishwasher use. These systems produce the highest amount of

waste hot water and therefore were considered in the scope of our project. We focused on the

development of the heat exchanger itself, while assuming other required information about our system.

To commence the project we performed in-depth research of our design idea searching for information

about current products and anticipated energy savings.

Through concept generation, discussion and refinement, a final concept design was established.

This design incorporated as many desirable features as possible to ensure the successful operation of

the device. Our final concept was a modular setup with each module consisting of a wastewater

reservoir and potable water coil immersed in the reservoir. This design proved to be a very effective

method of increasing boiler feed water.

A theoretical model was generated which analyzed our design concept using the flow conditions

established for our testing procedure. These both produced very comparable results, which further

reinforced the validity of our analysis. On average we saw a 9 ⁰C potable water temperature rise for the

majority of our tests. We originally anticipated a 10⁰C temperature rise, so our proof of concept model

illustrated the design very effectively.

The use of our device would save the end user around $70.00 per year, and while maintaining a

low initial cost the device would pay for itself over the course of several years. We tried to minimize the

costs associated with the device by using a simple design to make this project feasible. The viability of

such a device is dependent on the initial costs.

The final design we suggested incorporates many of the conclusions obtained from theoretical

and testing results. The recommendations section discusses other important project parameters that

would improve the device if further work was to be completed. The health and safety of our device is

described in-depth in the report along with risks and sustainability.


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2.0 Project Scope

The project team intends to design and develop a heat exchanger which facilitates heat transfer

from residential grey water to potable water before it enters a hot water tank. By transferring heat from

grey water to potable water, the team hopes to reduce the energy consumed by the hot water tank

while maintaining the same service level. Also having an increased service life for the end users HWT

should be experienced

The scope of the project is limited to the development of the heat exchanger itself while

assuming that hook-ups to selected devices and the sewer system are available at the final location of

the heat exchanger. The household devices considered to supply grey water to the heat exchanger are

limited to showers, bathtubs, and dishwashers. These devices were chosen as they typically use only

warm. Any auxiliary items that might be designed and optimized later are outside the scope of this

project.

Retrofitting this product into existing homes is outside the scope of this project. The original

idea when beginning this project was to approach building companies and try and integrate this product

into new builds.

The final concept selection can incorporate two distinct heat exchanger modules, a “coil”

module and a “tank” module. Both modules incorporate a grey water reservoir with overspill pipe to

temporarily trap water in the reservoir. The coil module is being designed to perform well during

simultaneous flow conditions, while the tank module is being designed to perform well during

prolonged residency periods. Unfortunately during the design process we were unable to build and test

the tank module, so the team cannot say with confidence that this would be a viable path to go down

for further design considerations. However a modular design was tested with the coil module and we

can say with confidence that the modular design is an improvement to the single module design.


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3.0 Background Research

Residential Greywater Heat Recovery:

A residential greywater heat recovery unit recovers heat from greywater discharged by end use

devices such as; showers, bathtubs, dishwashers, washing machines and sinks by transferring it into

household potable water before entering the hot water heater. The heat is recovered from the

greywater by passing through a heat exchanger where energy is transferred from the greywater to the

potable water.

The typical Canadian family living in a conventional new home uses 65 to 105 gallons of

domestic hot water per day. Heating this water with an electric hot water heater requires 5 000 kWh to

8 000 kWh annually, costing between $500 and $800 dollars per year. All this energy is used to heat

water and then after the water is used it is discharged into the sewer while it still contains much of the

original heat that was put into the water. By using a greywater heat recovery system some of the energy

left in the greywater that is normally wasted may be recovered and remain in the household.

There are many benefits to using a GWHR unit in a residential home as listed below:

- Energy savings and resulting decrease in utility bill.

- Increased first-hour rating of hot water tank.

- Improved comfort to household residents due to decreased hot water temperature degradation.

- Possible reduction in hot water tank volume and increased lifespan of tank.

By preheating the potable water going into the hot water heater there will be a decrease in the

amount of energy required by the heater due to the reduced temperature difference between incoming

water entering the hot water heater and the hot water heater set point temperature. The first hour

rating of a hot water tank is the amount of hot water that may be produced in an hour. This is an

important characteristic of a hot water heater because consumers determine which size/type of tank to

purchase based on this value matching their hot water usage. Using a GWHR unit increases the first-

hour rating of a DHW tank because the tank heats up water faster when the incoming water is

preheated resulting in a greater volume of hot water available from the tank in an hour. By increasing


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the first-hour rating residents will experience increased comfort if they had a problem with running out

of hot water before using a GWHR system and when purchasing a DHW tank it is possible to purchase a

smaller less expensive tank when used with a GWHR system.

Types of Residential Greywater Heat Recovery Systems:

There exist four different types of GWHR systems each with its advantages and disadvantages dictating

the best application:

1. Combined storage tank/heat exchanger that uses conduction and convection to transfer heat

from greywater to potable water.

2. Combined storage tank/heat pump that transfers heat from the potable water to the grey water

using a heat pump.

3. Non-storage type that connects directly to the household wastewater pipe.

4. Point-of-use device that connects directly to an end use device such as a shower and transfers

heat by conduction and convection.

Type 2 GWHR systems are typically used for industrial applications where the system is designed

specifically for its end application. These types of GWHR systems could obtain the greatest efficiency

and heat recovery but because of the cost associated with using a heat pump they are not practical in

residential homes. Type 3 and type 4 GWHR systems are the only types that are currently commercially

available. The products available consist of a 2-4 inch strait copper pipe with 0.5-1 inch copper pipe

wrapped around the exterior of the inner copper pipe. These products are attached directly to the

wastewater pipe to preheat water before entering the DHW tank or at end use device preheating water

before entering that device. Type 2 and 3 GWHR systems are limited by the fact that they can only

recover heat during simultaneous flow situations because there is no storage tank. Type 1 GWHR

systems are possible to be produced at a low cost because there is no heat pump or mechanical parts.

They are capable of recovering more heat than type 3 and 4 because of the use of a storage tank to hold

thermal energy for future use.


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Residential Domestic Hot Water Usage

An important factor dictating the economic viability of a GWHR system is the amount of hot

water consumed by a household. The amount of hot water consumed defines the amount of available

energy to be recovered by a GWHR system. Domestic hot water consumption varies among household

based on; family size, water heater storage capacity, geographic location, energy cost, number and type

of end use devices. There have been studies performed to determine the hot water consumption

patterns of typical households. Environment Canada studied the average water use in Canada and it was

determined that the average person uses 90 gallons of potable water per day. From this 90 gallons 40%

or 36 gallons is used for domestic hot water of which 90% or 32.4 gallons goes to shower use. Therefore

the average Canadian household of 2.5 persons consumes 90 gallons of hot water per day.

During shower use the flow through the GWHR system is simultaneous in that greywater flows

through the heat exchanger at the same rate as potable water. This accounts for 90% of the domestic

hot water use because it occurs during shower use and when using hot water in sinks. The remaining hot

water discharge is batch flow where greywater is discharged while there is no potable water drawn and

at a later time potable water flows through the heat exchanger without greywater flow.

Government Grants

Some government offer grants to residents who use energy efficient devices such as a GWHR

system. The Canadian Federal Government has been offering household energy retrofit grants which

include GWHR systems under the ecoENERGY efficiency grant program. A rebate of 95 dollars is offered

for GWHR systems which have an efficiency of 30-41.9% and 165 dollars is granted for GWHR systems

which have an efficiency of 42% and greater.

4.0 Concept Selection Process

This phase of the project was essential in establishing a model that would perform our desired

goal of recovering wastewater heat. This process initiated with an individual generation of concepts,

which produced a variety of possible ways to recovering this heat. Through group discussion and

concept refinement, we were able to finalize a concept that incorporated many of our design features.


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The process that was used involved generating and refining many concepts. While the inclusion of all the

beneficial design features was essential for a functional device, we had group discussions after every

stage of the selection process. We reanalyzed the concepts and completed several iterations of the

process. Eventually we arrived at a final design concept, which is discussed in the later parts of this

report.

Through the course of the concept selection process we generated a total of 13 different

concepts. To reduce the number of concepts down to the good designs, we used screening and

evaluation matrices to weight the concepts and eliminate the lowest scorers. These matrices are shown

in Appendix-H. The modified screening matrix reduced the number of concepts down to three and the

evaluation matrix analyzed the concepts against our design criteria listed below in the figure below.

Design Criteria Rank

Functionality 4

Sanitation & Safety 4

Cost 4

Size, Weight 3

Volumes of wastewater and potable water 3

Holding/Contact Time 3

Constructability 2

Practicality 2

Filtration/Cleaning 1

Mobility 1

We also added an additional concept which included most of our important criteria, which

ended up as our final selection. The final four concept sketches are listed below and are located in

Appendix - I:

• A – Group Concept 1

• F – Steve R. #1

• L – Ben R. #4


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• M – Group Concept 3

Based on the results from the evaluation matrices, design M (GR-3) turned out to be the best

option as determined when evaluated against our design criteria. The selection of our final concept was

in part due to the results of the evaluation matrix but we also generated this model and included as

many good features as possible so we knew this design would rank high.

5.0 Final Design Concept

The final design concept that we selected consists of a potable water coil in a reservoir of grey

water with an overspill arrangement. We have also designed the system to be modular by adding

additional units in parallel for increased potable water

temperature rise and associated heat transfer. The final

design we selected is illustrated in the figure on the

right. This Solidworks model show a solid view of the

modular design system connected to the desired piping

arrangement for our device. The figure on the following

page shows a cross-sectional view of the model.

For our final concept we wanted to incorporate

as many desirable design features as possible as listed

in our design criteria list below. This list was established

early during the term and helped with establishing a

proper solution to our design problem. Each one of

these categories was discussed and analyzed to include

all the design aspects of our project. The full table of

design criteria and the elements of each are listed in

Appendix - G.


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Design Criteria

- Weight

- Volumes of grey water and potable water

- Reservoir

- Internal tubes

- Hook up

- Solid sediment filtration

- Sanitation control

- Functionality

- Maintainability

- Efficiency

- Simplicity

- Safety Risk

- Environmental Impact

- Cost

- Robustness

- Insulation

After these criteria were discussed in relation to

our final concept, we developed an initial Solidworks

model that illustrated our final design. These preliminary

drawings are located in Appendix B – Initial drawing

package. After theoretical calculations and tests were

performed, we modified our initial final design to include

the results obtained from the design refinement analysis.

These final design drawings are located in Appendix B –

final drawing package.


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The main design features that we deemed necessary for inclusion in our design are:

- Overspill feature

- Greywater reservoir

- Potable water tubes/pipes

- Two layers of separation between greywater and potable water

- No potable water joints exposed to greywater

A list of possible design features that would be beneficial to include but are not essential are:

- Coil with coiled pipe/tubes (Simultaneous flow)

- Multi-stage/Modular design

- Device Emptying

- Solid sediment filtration

- Trap

- Conical shape (ease of emptying)

Our final design incorporates a potable water coil in a grey water reservoir. The coil we designed

for this use is illustrated in the photos below. In order to meet the specification of no joints exposed to

grey water, we have called for one continuous piece of coiled copper entering and exiting from the top

end cap. We have also specified a coating to be used on our coil for two layers of separation and

corrosion resistance. The coiling process produces some internal stresses in the copper tube which

increased the corrosion rate. This coating will be very thin as to not hinder the heat transfer from the

grey water to the potable water.

The modular design that is incorporated in our design can be used to expand the heat recovery

capacity of our GWHR unit. Depending on the average water use or size of the family, the modular

design can be implemented to recover the maximum amount of heat possible. With increased family

size and water use, the amount of water that would pass through our system would still have enough

stored heat in the water that would be cost-effective to recover. The connection of the second unit

would have the grey water pass through in series and the potable water would be connected in parallel.


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With the reduction of potable water flow by one half, the residency time in the device would increase

allowing more time for heat transfer.

We included an overspill feature that is installed between each connecting section to increase

the residency time of the greywater for maximum batch heat transfer. It functions basically like a

reservoir by holding the warm greywater in our device until a new batch of water enters the system. The

grey water inlet drain pipe extends to the bottom of the tank so the warm water pushes out the colder

water. We are also including a manual drain valve on our device for ease of emptying and there will be a

standard trap with valve for maintenance and cleaning purposes.

We decided on two main safety and sanitation specifications to ensure we meet the regulations

associated with potable water standards. The first is two layers of separation between greywater and

potable water. This is going to be accomplished by incorporating at a minimum two layers of separation

between water streams by using either double pipe components, providing a protective coating over the

tube and using a layer of plastic between components. We would also like to incorporate a method to

detect any leaks that would form in the device so that contamination does not occur. Our other safety

feature is to avoid any potable water joints exposed to greywater. To minimize the possibility of water

ingress through fittings, valves, etc., we want to have continuous components through the greywater

sections.

6.0 Theoretical Calculations

Theoretical Modeling

The project team has modeled the heat transfer occurring within the heat recovery device for

several operating conditions considered typical for a residential environment. These operating

conditions are defined below:

• Simultaneous Flow: Potable water and grey water both flowing simultaneously through

the device. The heat recovery device is subject to this condition during warm showers.

The simultaneous flow condition applies for 90% of hot water demand. (Environment

Canada 2004).


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• Potable Only Flow: Potable water flowing through the device with no grey water

flowing. This condition applies when filling a bathtub with warm water or opening a hot

water sink tap. The potable flow only condition applies for 10% of hot water demand.

(Environment Canada 2004).

Other operating conditions exist (such as grey flow but no potable flow) however they are of

little interest. This is due to the fact that the hot water boiler will only benefit from the pre-heating of

the grey water heat recovery unit when there is a hot water demand within the house. Therefore, the

conditions whereby potable water is not flowing through the device are ignored for the modeling.

The thermal circuit for the model is shown below:

Where: Rconv1 is the convection resistance in the flowing potable water,

Rconv2 is the convection resistance in the grey water reservoir,

Rconv3 is the convection resistance in the external environment,

Rcond1 is the conduction resistance in the potable water pipe,

Rcond2 is the conduction resistance in the 2nd layer separation material &

Rcond3 is the conduction resistance in the grey water reservoir.


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The heat exchange in during simultaneous flow is governed by the equation shown below:

(Incropera, p.472)

Where Tm,o is the outlet temperature of the potable water,

T∞ is the temperature of the grey water,

Tm,i is the inlet temperature of the potable water,

m• is the mass flow rate of the potable water,

cp is the specific heat of water (constant, 4184 J/ kg·K), &

U*A is a term accounting for the thermal resistances.

The grey water temperature T∞ is non-constant through time. In order to account for this, an

iterative energy-balance scheme was developed in Microsoft Excel (Appendix C). This allows potable

water outlet temperature Tm,o to be plotted against time. From the thermal circuit, U*A can be

evaluated as:

U*A = 1 / (Rconv1 + Rcond1 + Rcond2 + Rconv2) (Incropera, p.101)

The resistances are dependent upon the materials used and flow conditions within the heat exchanger.

The expected values used for these coefficients are stated below:


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Original:

-Thermal conductivity of copper pipe ‘Kpipe’ = 401 W / (m·K) (Incropera)

-Thermal conductivity of PVC grey water reservoir ‘Kres’ = 0.19 W / (m·K) (Incropera)

-Convection coefficient for potable flow ‘hpot’ = 1631 (W / m2·K) (Appendix C)

-Convection coefficient for grey water flow ‘hgrey,flow’ = 1000 (W/ m2·K)

(me.mtu.edu/~microweb/GRAPH/Intro/film)

-Convection coefficient for idle grey water ‘hgrey,idle’ = 750 (W / m2·K)

(me.mtu.edu/~microweb/GRAPH/Intro/film)

The convection coefficients initially considered were based either on a general ranges of

convection coefficients for given scenarios of an attempted analysis for a similar condition for the coil.

These coefficients were modified such that the theoretical model fitted the experimental data

reasonably well. The experimental data is presented in (Appendix C) while the predicted values

calculation procedure is presented in (Appendix C). Through comparing both data, the following

correction to the initial values of the convection coefficients was observed to provide a better fit:

Revised:

‘hpot’ = 3000 (W / m2·K) (Appendix C)

‘hgrey,flow’ = 900 (W/ m2·K) (Appendix C)

‘hgrey,idle’ = 750 (W / m2·K) (Appendix C)

The revised values for the convection coefficients were a result of a trial and error best fit of

model testing data which is illustrated in appendix C. These coefficients may not provide the best fit for

all scenarios, but for those demonstrated in the lab, this combination performed reasonably well.

Second Layer of Separation Effect

The average values of potable water outlet temperatures predicted for both simultaneous flow

and potable flow only while considering the effect of the second layer of separation are shown in the

next figure for given conditions. This condition is also modeled in Microsoft Excel (Appendix C).


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Given Conditions

Mass of Grey in Reservoir

= 53.20085 kg Volume Reservoir = 530.9L Reservoir

Mass of Pot in Coil = 0.47904 kg Volume Coil = 480mL

Mass Flow Rate Grey = VARIED gpm VARIED

Mass Flow Rate Pot = VARIED gpm VARIED

Initial Temp of Grey = 293.15 K 20 ºC

Initial Temp of Pot = 293.15 K 20 ºC

Incoming Temp Grey = 310.15 K From shower, incoming temp = 37 ºC

Incoming Temp Pot = 280.15 K City supply = 7 ºC

External Temp = 293.15 K Room temperature = 20 ºC

Length of Coil = 6.096 m 20 feet

Req1 = VARIES K/W

=0.005493 for no 2nd layer, 0.007840 for 2

nd layer

(http://www.epoxies.com/therm.htm)

Req2 = 15.822 K/W See Thermal Circuit


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Average Predicted Temperature Rise of Potable Water for

Simultaneous and Potable Only Flows

0

1

2

3

4

5

6

7

8

9

10

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Flow Rate (gpm)

Tem

pera

ture

Ris

e (°C

)

Average Temperature Rise of Potable Water during Simultaneous Flow

Averagre Temperature Rise of Potable Water During Potable Only Flow

Average Temperature Rise of Potable Water for Simultaenoues Flow - 2 layer Separation

Average Temperature Rise of Potable Water for Potable Flow Only - 2 Layers Separation

Average predicted temperature rise of potable water for simultaneous flow and potable flow only

conditions consider both 1 and 2 layers of separation.


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The average temperature rise for the given flow rates considering 90% simultaneous loads

and10% potable only loads are compared for the varying flow rates in the table below.

Average temperature rise reduction due to second layer being considered for multiple flow rates.

The second layer of separation was assumed to be a 1 mm layer of thermally conductive epoxy

(Kepoxy = 2.162 W/ m·K). From the table, a 0.978ºC temperature reduction was seen when introducing the

2nd layer of separation at 1.5 gpm, while a 0.802 ºC drop was seen when analyzing the 2nd layer of

separation for a flow of 2.5gpm. Therefore, an expected temperature rise reduction due to the 2 layer of

separation is expected to be on the order of 1ºC for most typical operating conditions. The value of

energy not recaptured due to the 2nd layer of separation is tabulated below.

Flow

Rate

(gpm)

Average

Temperature

Rise of

Potable

Simultaneous

Flow - 1

Layer (ºC)

Average

Temperature

Rise of

Potable

Simultaneous

Flow - 2

Layers (ºC)

Simultaneous

Difference

(ºC)

Average

Temperature

Rise of

Potable

During

Potable

Only Flow 2

Layers (ºC)

Average

Temperature

Rise of

Potable

During

Potable

Only Flow 1

Layer (ºC)

Pot Only

Difference

(ºC)

Weighted

average temp.

rise 0.9*SimDiff

+0.1*PotOnlyDiff.

1 9.3126 8.2053 1.1074 2.8800 3.2434 0.3635 1.0330

1.5 7.3910 6.3524 1.0386 2.3936 2.8232 0.4297 0.9777

2 6.1131 5.1753 0.9378 2.0357 2.4779 0.4423 0.8882

2.5 5.2086 4.3652 0.8434 1.7674 2.1999 0.4326 0.8023

3 4.5366 3.7746 0.7619 1.5605 1.9747 0.4142 0.7272

3.5 4.0182 3.3254 0.6929 1.3969 1.7899 0.3930 0.6629

4 3.6065 2.9723 0.6342 1.2645 1.6361 0.3717 0.6080

4.5 3.2717 2.6875 0.5842 1.1553 1.5065 0.3512 0.5609


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Control Scenario =4ppl X (10 min shower + 3.43 gpd pot only)

1.5 gpm showers 2.0 gpm showers 2.5 gpm showers

GPD = 73.72 93.72 113.72

delta T = 0.9777 0.8882 0.8023

Cost Savings

(kWH/yr) Reduction

Per Year = 75.2038817 86.85450802 95.19693351

at 10 cents / kWH,

Cost savings

reduction per year

due to 2nd layer = 7.52038817 8.685450802 9.519693351

Average cost savings per year reduction due to considering 2nd layer of separation.

7.0 Detailed Design

The final design the team decided to go with is a modular design. The Reservoirs are fed by

shower water, ideally at a somewhat close range to the module one or two floors up. This will ensure

little losses through the line as the water reaches the device. Water is fed into the first module and fills

it until the coil is surrounded by the incoming grey water flow. The overspill allows for water to pass

from the first module to the second module in a short distance of tubing. The second reservoir, which

operates at a slightly lower temperature, but still has some appreciable heat to recover, is filled after the

first one begins to spill over into it. The second module can either have a coil design or a tank design.

Further design is required for us to say whether or not this would result in more heat transfer, it remains

as a potential idea for future work on the project.


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The Geometry for each module is as follows:

Reservoir Dimensions inches

Outter Diameter 10.79

Inner Diameter 10.00

Height 24.00

End Caps(cut to 10.79") 0.75

Coil Dimensions inches

Height 20.00

Spacing 1.50

Number of coils 16.00

Connectors inches

Overspill 2.00

Inlet pipe 2.00

Drain Valve 0.75

Hose 180.00

The reservoir we had originally sized for this project was too large to get the exact conditions

that we wanted on the inside of the reservoir. If the reservoir was smaller, the equilibrium temperature

would be reached faster and the system would behave more ideally. That is, there would be less of a

build-up curve on the inlet temperature versus time curve when the system is starting up.

For determining the optimum length of copper tubing for the model testing, a mathematical

model was constructed using the heat transfer principles learned in previous courses, and from the

“Introduction to Heat Transfer”-Incopera textbook. The model was constructed in Maple 15, and the

optimization was based on the course material in Yuri Muzychkas Mechanical Systems course the group

is currently taking. The Maple code is attached to this document with all relevant plots and graphs

associated with it. It can clearly be seen, that for the convection coefficient one would expect for the

internal flow of the copper coil, and the convection coefficient expected in the reservoir part, the

optimal length of copper coil came out to be roughly 25ft. This is based off a best case scenario,

assuming a uniform surface temperature on the copper coil, and the water in the reservoir is at peak


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operating temperature (roughly 38 degrees, right after a shower replenishes the reservoir). The model

was solved for the point on the graph where the coil length gave us our ten degree rise we strived for in

the mission statement. This is the temperature rise we feel will make this project economically feasible

based on initial estimates for a ten degree rise. Our group feels that this length of copper will get us the

heat transfer we need to reach our target average outlet temperature of ten degree Celsius.

The potable water lines for the two modules would be split, so the effective flow rate going

through the lines would be cut in half. This would promote heat transfer through both units and we

would expect to see an overall increase in efficiency when operating the unit with module 2 installed.

We were able to prove this theory with our model testing. When compared to the regular 1.5 gal/min

flow rate of a low flow shower head, splitting this in two made the efficiency of the heat exchanger jump

from roughly 30% to 45 or 46%. This is significant to note and will be included in the design

recommendations.

The overspill pipe to the second unit, and the inlet grey water pipe for the first unit both extend

to the bottom of the device, this is so the hot water flowing into the system is forced to the bottom of

the device, and the more buoyant warm water will rise to the top, passing over the coils and transferring

heat as it goes. As a note to improve the design, baffles could be added horizontally in the tank in

between the coils. This would increase the distance of the flow path the grey water must travel in order

to reach the overspill at the top of the device. The turning of the liquid through the channels created by

the baffles will also create a new unique convection environment, where slight eddy currents in the flow

will brush over the coil and increase the effective convection coefficient in the reservoir.

The end caps were made on a lathe in the machine shop. By simply stepping the lid in to the

inner diameter of the reservoir, tight fitting end caps were easily made. These were fitted with holes for

the hose connections.

The stand is incorporated for visual purposes only and was outside the scope of this project to

design, however the model in Solidworks shows what a typical setup like this might look like in an end

users basement. The dual module system would sit in the stand (similar to what the group has shown

here in Solidworks) and would be connected to the houses shower drains and city supply line. The

modules would sit in close vicinity to the HWT to reduce and losses in the lines seen when traveling from

the heat exchanger to the HWT. This might also have positive effects on the reservoir temperature, if


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the line is short enough, hot water from the HWT will egress back into the pipelines in the coil module

due to thermal expansion of the fluid in the HWT, heating the grey water from the inside so that it might

heat the colder potable water behind the hot when an appliance begins to draw hot water again.

Due to unforeseen issues with the coiling operation of the copper tubing we purchased, the final

design coil diameter was increase from 3 inches to 6 inches. This will make coiling efforts a lot easier if

this model were to be reproduced. Also, now that the design calls for two layers of separation with a

coating applied over the entire surface of the coil, the contact between the drain pipe and the coil is

irrelevant because the coil is always surrounded in grey water at all times. The contact between the

drain pipe and the coil was intended to accommodate simultaneous flow loading into the device;

however it was seen in the model testing section of this report that it accommodated both simultaneous

and batch flows quite well, and we were almost able to achieve the heat transfer we had set out as a

target increase in potable water inlet temperature.

8.0 Model Construction

The model construction phase began in early March with the procurement of the materials. The

groups only purchase was 20 ft of copper coil, purchased through Rona located in Kelligrews, NL. In the

plan, the group was to provide a technical drawing package to Technical Services for the coiling

operation by March 12th so that the workers in tech services could know in advance what we wanted to

achieve for our model test. The coil module will be made of ½ inch soft type L copper tubing, coiled over

a 2 foot height and a number of turns somewhere around 15 turns for a 3 inch diameter drain pipe.

These estimates were based off original estimates from the optimization analysis.

The copper coil tubing will be wrapped around the 3 inch copper drain pipe and mounted to the

cover of the GWHRU. The copper coil will be connected with copper connections and routed through

the top end cap as well. Then hoses with hose clamps will be fitted to the copper tubing and also to the

two sink connections.

Shown on the following page are pictures of our constructed model showing the grey water

reservoir and the potable water copper coil.


22

The copper coil tubing will be wrapped around the 3 inch copper drain pipe and mounted to the

cover of the GWHRU. The copper coil will be connected with copper connections and routed through

the top end cap as well. Then hoses with hose clamps will be fitted to the copper tubing and also to the

two sink connections.

The reservoir will be made of a pipe we have been given from a father of a group member who

works for the city. The pipe is a 12 inch HDPE pipe and will serve as the grey water reservoir for the

model testing. The bottom will be glued and sealed with silicon to remain leak proof. The end caps will

be made of ¾ inch PVC sheet plastic we purchased through Tech Services for a nominal fee and labour

charge. Technical Services must also prepare to bend the material on the lathe, and will also have

charges for labour associated with the coiling operation. The top end cap of the pipe will have 2 holes

cut to allow connections through to the sink faucets. This end cap will be stepped in on the bottom edge

on the lathe to fit into the inner 12inch diameter. This will not be sealed to allow for easy dismantling.


23

The Reservoir will be fitted with an overspill to allow for flow though the unit. The overspill will

be a 2 inch elbow connection drilled into the side of the reservoir; it will be glued and sealed with silicon

to prevent leaking, and to keep it in place testing.

The following vendor list was used for the acquisition of our materials and supplies.

Model Construction Process

First the bottom end cap will be glued into place with contact cement to prepare the water tight

seal. The top end cap will be left un-glued for easy removal. While the glue is drying, the coil must be

prepared and fitted for connections to allow for cold and hot water to be connected from faucets in the

fluids lab. The ends of the copper coil must be widened and made more circular before they can be

fitted with hoses and hose clamps. The hoses will be drawn through the top end cap and left at an

appropriate length for testing.


24

The hoses must then be drilled with holes to allow for thermo couple wires to be exposed to the

passing stream of water. A hole must be drilled in the top end cap as well for a thermocouple wire to be

passed through to test the outgoing greywater temperatures. There are a total of 4 testing points, so 4

holes must be drilled.

The bottom end cap will then be dry, so the silicon sealant can be applied to the exterior edge

and the interior surfaces of the end cap, to allow for a perfect water seal given the loading conditions.

Once the silicon has been applied it must be left to dry for a few hours.

At this point, the copper coil must be hydro tested to ensure no leaks are coming from the

potable water lines in the system. Once the sealant is dry on the reservoir, it must be hydro tested as

well to ensure no leaks occur during testing.

The next step in the construction plan would be to cut holes in the reservoir for the overspill

elbow and the drain valve. The drain valve hole is sized at ¾ inch NPT pipe tap, so the hole we cut must

be 29/32 inches in diameter. Once the hole is tapped, plumbers tape is applied to the drain valve and it

is screwed into place. The over spill hole is cut to a slightly larger diameter hole than the overspill elbow,

and is then contact cemented into place, and sealed with silicon to ensure there are no leaks during

testing.

Finally, the taps for testing must be calibrated to 1.5, 2.0 and 2.5 gallons per minute before

testing begins. The mixing tap must be 1.5 gallons per minute as well at 37-42 degrees Celsius (the

average incoming temperature expected from showers), and the cold potable water incoming

temperature is of no significance (that is, the average temperature rise is what the group is after). The

taps are marked off with a marker and flow rates will be verified with a bucket/timer setup, calculating

values in gallons per minute.

Final Model

The material the group had procured for the project was a ½ inch copper tubing type L “soft”

copper. Unfortunately for us, it took a longer than anticipated amount of time for us to procure the

copper tube. Dave Snook in tech services and I inspected the copper when it arrived. By initial inspection

Dave knew the copper was not going to react well to the coiling process. The wall thickness was too

large for the type of bending operation they had planned for the coiling. The copper could not under any


25

circumstances go onto the originally designed drain pipe. Therefore the only thing that could be done

was have it applied on a different coil diameter. 6 inches was the new diameter for the coil unit. We

accepted this and the fact that the coils would flatten out to some degree because it would still fit in the

unit and, theoretically you can control the flow through the unit with the cold water tap, the

temperature can be measured and put into our mathematical model.

So, to summarize, the finished model looks exactly the same other than the coil module itself.

The coil will allow for no extra copper to be bent for connection. This leaves the only alternative for this

to be hose connections right in the reservoir itself.

After model testing, the group plans to clean off and grind smooth the exterior of the reservoir

for esthetics. The reservoir will be painted and the company logo will be stenciled on the outer surface.

Colors are to be determined at a later date.

Cost of Model

The model costs included a 20ft length of copper coil which we purchased through Rona, the

charges applied through tech services for the work they performed (cutting 2 end caps for our reservoir

and coiling the copper around a 6 inch pipe). For model testing purposes the project required a few

extra purchases that the group decided to finance for rapid acquisition. The project team bought 15 ft of

garden hose, hose clamps, 6 feet of 2” rubber hose, 3 ft of pvc 2” drain pipe, some PVC cement and

silicon sealant from KENT building supplies.

The bill of materials for the model prototype is seen in the next figure. It can be seen that for

the limited budget we had for this project, we were still able to produce a working model for under the

allotted amount of money. This is good, because the amount of money we expect to save people isn’t

going to be enormous. That means, in order for this project to stay feasible, the overall cost of the

product cannot be too high.


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Bill of Materials

Material Quantity Unit Price Total Cost ($)

Copper Tube 1/2" 20ft 2.26$/ft $51.98

Resevoir for Sheath Comp. 1 ea. DONATION $0.00

Second Reservoir 1 ea. DONATION $0.00

City Water Reservoir 1 ea. DONATION $0.00

Work Space Fluids DONATION $0.00

Tech Services 3 hr 10$/hr $115.00

Miscellaneous 3 ea. 10$ ea. $50.00

$216.98

Note: Actual model cost if price of donation items are included is $256.98

9.0 Model Testing

For the model testing phase we set out to simulate typical household hot water use scenarios

and gauge the effect on energy savings. This involved designing different types of experiments to match

the flow characteristics of two main types of typical residential waste water flow - simultaneous and

batch flow. Simultaneous flow is when potable and grey water are running through the device, which

can be used to model shower and dishwasher operation. This type of flow condition will account for the

majority of hot water use in a typical household and therefore was the main concern for our testing

procedures. The Design of Experiments used for this process is included in Appendix D.

The data acquisition aspect of the testing included modifying the constructed model to include

points of insertion for the temperature monitoring probes. Temperature readers and thermocouples

were used to record the results of our potable and grey water temperature rises. Four main points were

used to measure the temperature rises – potable water in and out and grey water in and out.

Temperature recordings were taken every 30 seconds for each test, so that we could analyze the


27

transient aspects and steady state operation. This proved to be ample time for observing the

temperature trends during the operation of our device.

To simulate actual water use in a home a specific scenario was established. This was achieved by

modelling a typical morning water use scenario that consists of three 10 minute showers with two 5

minute breaks. This test was run using different potable water flow rates to simulate different types of

typical shower fixture flow rates. This test produced some very informative results about the amount of

heat transfer associated with using low flow shower fixtures.

We also wanted to test the modular design to determine its efficacy of recovering heat while

still maintaining its feasibility. The multi-stage system design was potable water lines connected in

parallel between the two modules, hence reducing the flow rate by one half. A flow rate of 0.75 gal/min

was used for these tests assuming low flow shower fixtures. The first stage was run using an initial

reservoir temperature of 24 ⁰C and the system was left running for 10 minutes. To achieve a multi-stage

test, the final grey water temperature out of the first test was used as the incoming grey water

temperature of the second test. Considering our overspill feature this water would be flowing into the

second module at the grey water outlet temperature of the first

Batch flow was modelled with only potable water flowing through the device, while holding the

grey water flow at zero. This simulates sink use or a bathtub slosh through the device. We modelled sink

use by setting the tank temperature at room temp and running the potable water. We modelled a

bathtub slosh by raising the tank temperature to 40 ⁰F and running the potable water through the

device.


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The exact listing of performed tests is given below with some detail on each test type:

Potable water and greywater flowing (Shower and Dishwasher)

1. Testing Type 1 – Three 10 minute showers with 5 minute breaks

a. Q = 1.4 gal/min

b. Q = 1.6 gal/min

c. Q = 2.0 gal/min

d. Q = 2.5 gal/min

2. Testing Type 2 – Continuous running for 20 minutes for Q = 2.5 gal/min

3. Testing Type 5 – Decrease reservoir volume

Potable water flow only (Sink use, bathtub slosh)

1. Testing Type 3 – Q = 1.5 gal/min

a. Reservoir temp at room temp

b. Reservoir temp at 40 ⁰C

Multi-stage flow (modular design)

c. Testing Type 4 – Two passes in parallel

i. Flow rates in half, reservoir temp of 2nd test to be at grey water out of first

reservoir


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Testing Results

Based on the tests listed above the average temperature rise and associated efficiencies are

tabulated below.

Test ΔT (⁰C) Efficiency (%)

Typical Morning

Q = 1.4 gal/min 9.85 30%

Q = 1.6 gal/min 8.92 28%

Q = 2.0 gal/min 8.62 24%

Q = 2.5 gal/min 7.68 23%

Multi-Stage Design

1st

stage (Q = 0.75 gal/min) 14.50 43%

2nd

stage (Q = 0.75 gal/min) 11.51 49%

Batch Flow

25⁰C Tank (Q = 1.5 gal/min) 5.43 30%

40⁰C Tank (Q = 1.5 gal/min) 9.75 42%

The results obtained from the tests were very helpful in identifying temperature rise trends

associated with different operation of the device. The full set of testing data and results are included in

Appendix E. Possible model improvements were also identified from the results and incorporated into

our final design. The typical morning scenario produced some very comparable results to the theoretical

model and illustrated a very important relationship between flow rate and heat transfer. The multi-

stage tests also confirmed the feasibility of using a modular arrangement for increased cost savings. The

batch flow tests were also as predicted, with a gradual decrease in temperature rise over time.


30

The results of the typical morning hot water use scenario were very beneficial in establishing

design improvements and future prototyping ideas. These results indicated that lower flow rates

produce larger temperature rises. This is intuitive due to the fact that with lower flow rates the

residency time of potable water inside the tubing would increase. In the figure below the temperature

rise for typical morning use is plotted for different flow rates. As evident from the black line on plot

below the lowest flow rate Q = 1.4 gal/min generated the largest temperature differential.

The multi-stage testing results confirmed the feasibility of using multiple modules for homes

with high hot water consumption. Illustrated in the figure below, reducing the flow rate by one half

results in a much larger temperature rise for potable water. In the first stage of operation we see an

average temperature rise of 14.50⁰C which is well above the single module value. In the second stage

we see a 11.51⁰C temperature rise by using the lower greywater inlet temperature. On average, this

produced a temperature rise of 13⁰C, which would result if the lines were to tie back in together. In


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comparison to an average temperature rise for one module operating at the same flow rate of 8.92⁰C,

we see a 4.08⁰C rise using two modules. This result proved that the use of a modular design would only

be beneficial in large families with high hot water demand loads. The initial cost of fabricating an

additional module would have to be weighed against the hot water use to determine payback periods

exactly. Illustrated in the figure below is the average temperature rises for the multi-stage operation in

comparison to the single module operation. As can be seen the multi-stage arrangement produces an

increase of 4⁰C in average temperature rise compared to the use of one module.

The batch flow analysis also produced good results. The temperature rise of the potable water

was much better for the higher internal reservoir temperature of 40⁰C, where it produced an increase of

9.75⁰C. The two plots listed below are indicating the decrease in temperature difference over time for

25⁰C and 40⁰C tank temperatures respectively. As can be seen the 40⁰C plot has a much higher average

temperature rise and the decreasing converging lines would continue out the page for prolonged heat

transfer.


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10.0 Energy Savings

The idea behind making this project economically viable is taking unused hot grey water from

your shower and dishwasher, and using it in a safe and efficient way to transfer heat to the incoming

city water supply going to your hot water boiler. This will result in a jump in the incoming potable water


33

temperature, which will put less of a demand on your hot water heating elements (be they electric of

natural gas). It all breaks down into a temperature difference seen at the HWT tank inlet, and a kilo-

watt-hour savings per year and gallons per day water usage, which can be multiplied by roughly ten

cents per kW-hr.

Given the following equation for energy consumption per year, we calculated the energy saved

per year when comparing the usage of our system against the same hot water tank use but with no

temperature rise from a GWHRU.

For an Electric Water Heater:

UECe = (Use * TempRise * SHW * 365) / [3413 * (EF/100)]

UECe = unit energy consumption (kWh/yr)

Use = household hot water use (gallons/day)

TempRise Average temperature rise of incoming potable water (F)

SHW = specific heat of water (8.2928 Btu/gallon-F)

3413 = conversion factor (Btu/kWh)

EF = energy efficiency factor from DOE test procedure (%85 assumed)

The annual savings calculation for a ten degree temperature rise for incoming potable city water

is as follows. Our test home will have 4 showers per day and a dishwasher load every 2 days. With a flow

rate of 1.5gpm and 10 minute shower allowance we deduce that 60 gallons per day can be used to

recover heat to incoming water supply. Also assuming this households hot water tank is set at the

national average of 55 degrees Celsius, and that incoming potable water comes in at the national

average of 11 degrees Celsius (Ontario Power Authority 2003). Under these scenario conditions, we plot

the kwhr savings and the dollar value savings per year after using this device. The graph show the

gallons per day usage increased from 10 to 60 gallons per day, and a jump in dollar value savings from

20$/yr to 120$/yr.

Listed below are plots of theoretical energy and cost savings associated with the device.


34

KW-Hr savings per year seen from ideal device:

Cost savings seen from using device per year:


35

Model cost savings vs. Theoretical cost savings. This is based on the average temperature rise

seen through experimentation of 9 degrees.

It can be seen that our model did not quite meet the target goal, however we were close. The

drop in cost savings can be seen from the fact that our models coil was flattened out, decreasing the

volume in the coil and increasing the velocity of the fluid passing by. The negative effect is that less heat

transfer occurs due to shorter resonance times. We as a group still feel that we could have achieved our

milestone temperature rise if we had been more equipped for the cold working coiling operation

needed for the success of this project.

11.0 Environmental, Health, Safety, Risks and Sustainability

Health and Safety

The only major safety risk of a GWHR system is the potential contamination of potable water by

greywater. Greywater contains bacteria which would pose a major health risk to residents if it were to

enter the potable water stream. The risk is very low but due to the extreme health risks associated with


36

contamination and the fact that a leak could go undetected, it is necessary to use measures to eliminate

this risk. The final design eliminates this risk by:

• Using two layers of material separation between the potable water and greywater streams.

• No potable water joints exposed to greywater.

• Potable water stream at higher pressure than greywater.

Two layers of separation between greywater and potable water are required so that if a leak

where to occur than it would be contained by the second layer. Because a rupture in one of the layers

could go undetected it is necessary to perform an inspection of the potable water coil periodically to

ensure both layers are intact. The copper potable water coil in our final design would be made entirely

out of one length of copper so that there would be no connections exposed to greywater. This reduces

the possibility of a leak occurring by eliminating connections which have a much greater chance of

leaking than the pipe itself. The greywater in the final GWHR system design is at atmospheric pressure

and the potable water stream is at the city water supply pressure therefore if a leak where to occur it

would be from the potable water into the greywater and no contamination would occur. While

performing cleaning and or maintenance on the system the potable water and grey water lines bypass

the GWHR unit causing a situation where the potable water pipes are not pressurized but still

surrounded by greywater until the tank has completely drained. This scenario could allow grey water to

enter the potable water pipes if there where a rupture in both layers of the potable water lines. To avoid

this scenario it is mandatory to keep the potable lines pressurized while the greywater is bypassed and

the tank is completely drained of greywater then the potable water line may be bypassed.

Risk and Sustainability

The Fluggen GWHR system is a sustainable design by default because the purpose of the system

is to reduce household energy consumption. The system is very sustainable due to its long life of at least

ten years. This is achieved because all components are corrosive resistant and there are very little

stresses applied to the device. At the end of its lifetime the Fluggen GWHR system would have a minimal

impact on the environment because the majority of the components could be recycled or reused.


37

Environmental

Depending on the method of electricity production the use of a GWHR system will reduce the

amount of carbon dioxide produced. If a natural gas hot water heater is used the reduction in

greenhouse gas emissions is directly proportional to the reduction in the water heaters gross energy

consumption. For every 1 kWh of natural gas consumed produces about 0.0018 tonnes of carbon

dioxide. Therefore based on our model the average family using 32.4 gallons of hot water per day

resulting in 500 kWh per year would reduce their carbon dioxide emissions by 0.9 tonnes. At the high

spectrum of hot water use a household using 60 gallons of hot water per day would reduce their carbon

dioxide emissions by 2.16 tonnes. If using an electric hot water heater where the electricity is coal-

generated a household consuming 32.4 gallons of hot water per day would offset 4.1- 4.85 tonnes of

Carbon Dioxide per year.

12.0 Design Review

The design began slowly and involved a large amount of thorough planning and researching

before a final concept was selected. Once we selected the final concept the team had a rough idea of

what the final design would look like. This was much smaller in scale than the final design you see in this

report today. The second iteration of the design was capable of holding much larger amounts of water.

The pipe we had donated to us was a 12” diameter HDPE sewer pipe. This was the best thing we had

available to us. After testing this model we realized that the volume inside the reservoir was too heavy

to pick up, and we were having trouble with mixing and time to reach equilibrium. The final design today

has a ten inch diameter to fine tune the volume of grey water so that it has a better heat transfer

characteristic. The smaller volume in the tank will be replaced with hot water faster, and the average

temperature in the reservoir will rise faster than that of the 12” diameter reservoir.

In design it is always important to realize where you went wrong after you reflect on what

you’ve done, and determined what goals you set out to accomplish, and whether or not those goals

were satisfied. The group feels that our goal was nearly accomplished. We proved that it is possible to

recover the heat typically lost through shower and dishwasher water and turn it into cost savings and a


38

reduction on the demand of the hot water tank. This goal was accomplished, however the group could

have performed certain tasks better and the outcome of this project could have been much greater.

Time management is something the group could have improved on. Getting instrumental

documentation prepared for review on time was proving hard sometimes throughout the term. If a

harder grasp had been taken on following our internal deadlines, the project could have ran a lot

smoother.

13.0 Design Recommendations

Baffles – Baffles are recommended to be installed in horizontal positions along the reservoir

walls. The baffles would be circular in cross section and be made of similar materials. By introducing

baffles to internal grey water flow through the reservoir, increased convection coefficients will be seen

near the coil surface, promoting heat transfer. Not only this, but by making the reservoir path longer for

the grey water, a more even temperature distribution can be seen throughout the reservoir. This will

cause our system to react more ideally to system parameter changes, and we feel, will increase the

average heat transfer seen to the incoming potable water in the coil.

Reduced volume – The model our group constructed was a 12” diameter HDPE sewage pipe. A

similar material is recommended for this device. However, during testing it was noted that for low flow

rates (1.5 gal/min) the mixing of temperature in the reservoir was equilibrating at a much slower rate

than we once predicted. To counteract this ill effect, the reservoir diameter must become 10”. By

reducing the effective volume of the reservoir by 20L, the operating temperature of the device can be

reached more quickly, ensuring that by the end of the first shower in a day’s cycle, the reservoir can be

thought to be operating at its peak temperature, ensuring future results are consistent. It is thought that

the effect of cooling from the copper coil will have a counteracting effect on the overall operating

temperature of the device. The average operating temperature seen in the reservoir should remain

reasonable unchanged after the design change is taken into account. This however would have to be

proven with additional testing.

Permanent connections – Permanent connections leading from the copper tubing should be

installed in an improved prototype. The group had initially intended to do this, however due to the


39

unique circumstances with tech services and the coiling operation, no copper was left over for their

fabrication. The copper connections would come from the top and the bottom of the coil. The elbows

would not be so large as to not fit inside the reservoir. The connections would come up through the top

end cap of the reservoir through pre drilled holes. They would be mounted at a set distance and sealed

into the holes so the whole assembly could be lowered in for sealing. The ends of the copper would be

cut short to the reservoir top and soldered connections would be put in place to make this device easy

to install into the home. That is, it fits right in to standard water line connections.

Cover – The cover would be sealed in place after to decrease the heat losses to the

environment. All other places where heat could be lost would be sealed as well.

Coating – A protective coating would have to be applied to the finished product (the coil) after it

is ready to be installed. The coatings could be metallic, paint or an epoxy dip. This would be to ensure

prolonged corrosion protection against the environments the grey water would subject the surface of

the coil to. This would effectively provide the two layers of separation between grey water and the coil,

ensuring no joints are exposed to grey water since the connections would be soldered in place. A

recommended product would be something like Polyamide Epoxy coatings for pipe, ceilings and other

industrial uses. The product description from the manual is this:

This two component epoxy offers excellent impact and abrasion resistance, plus has good acid and alkali

resistance. This product is for use on properly prepared interior & exterior ferrous metal, galvanized

metal, wood, plaster, and masonry and drywall surfaces. Examples include commercial and institutional

walls, ceilings, machinery, piping, cabinets, storage tanks and high traffic floors.

Features

• High gloss extremely durable stain resistant film

• Very good impact and abrasion resistance

• Good acid and chemical resistance

• Very good alkali resistance

• Resists strong cleaning compounds

• Solvent resistant

• Tile like finish does not support mold, mildew, or fungi growth

• Forms a dense, waterproof barrier coat


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This coating is expected to perform quite well under the process conditions outlined in this

report. It would be the first scenario we would test. If it was sufficient we would move on however if for

some reason it failed, another materials would have to be researched and selected. Some benefits of

using an epoxy dip is that it is simple and easy to apply, and a bucket of epoxy is good for coating a large

number of coil modules.

Tank Module – Exploring the idea of a tank module further would be an interesting venture. The

idea behind the tank module is to increase the volume of city water in the reservoir, effectively slowing

the flow rate through the city water tank to very low rates. This would promote a much greater heat

transfer rate to the city water than the coil. The tank would also have to be dipped to ensure 2 layers of

separation between grey water and city water. Additional testing would have to occur for the new

modeled prototype. Some SolidWorks drawings are provided in the appendix for how a tank module

might look. The tank module could be connected in series with a coil module to provide both prolonged

heat transfer from the tank and the immediate heat transfer seen by the coil module during

simultaneous flow operations (showering). Also something worth nothing, by introducing this new

design, it would make fabrication costs increase. The manufacturing plant now would have to have two

sections, one for tank modules and one for coil modules. Where is we kept a simpler design of using two

coil modules in series then the manufacturing of this product would be simpler with less room to make

mistakes.

Testing – Varying system parameters have sometimes costly effects. Having to redo tests is

never an effective way to work. Measures to control flow rates should be implemented for testing. This

test was a rough estimate of what might actually occur in the system, but a more accurate setup, using

the new prototype should be implemented, with a flow regulator used for testing to provide more

accurate results. Permanent temperature testing site could be mounted to the copper inlet tubes and

overspill. This would eliminate leaking due to holes drilled for thermocouple wires. Testing multiple

configurations for the modular design is a good idea. Changing the potable water connection from

parallel to series could have different results, and they are important to note for installation purposes.

Slanted Reservoir Bottom – Having a slanted bottom that ran to the drain valve would ensure all

waste seen from devices is immediately sent down the drain after emptying.


41

Servo Valve, Automatic Draining - An idea to reduce the costly marketing effects seen by having

to come and clean the device every so often is to include a self draining mechanism into the unit to

ensure that after peak operating hours, when the reservoir is full. Once the tank temperature reaches

that of the ambient room the valve will open, draining the device entirely straight into the sewer

(through a trap to ensure no sewage air could egress into the home). Some code would have to be

written for the servo valve programming. An overspill feature would still installed for added safety, in

case the servo valve fails to open. If this were to be achieved on a prolonged basis the effects of

maintenance really would disappear. However this introduces a new variable into the mix, the servo

valve would have to the run on electricity. It can be expected that for intermittent use the electrical

costs associated with this would be quite low, however they would have a negative effect on the overall

cost savings of the device. To what degree, it is not known at this time; however it could be evaluated in

a later stage of the design.

Peak Operating Hours – The peak operating hours is defined as the length of time during the day

where the hot water demand is highest. This design is under the assumption that showers are occurring

one after the other, when in actually fact, they very well might not do this. In order for our model to

work most efficiently, the showering needs to occur all around the same time. This is a flaw in the design

in the end of the day. Our model should be able to accommodate any flow characteristic. Increasing the

robustness of the design would be a key goal if this project were to move forward. Anyone taking on this

design challenge in the future should take this into consideration, and put more research and thought

into improving this aspect of the device. (Servo valve idea would have just that effect, the effective

temperature is much high when filling the tank. It would have to be designed in such a way that the tank

filled quickly so that the liquid covers the coil as fast as possible. (This would promote good heat

transfer, faster).

Increasing Coil Diameter - By increasing the coil diameter, the flow can be expected to slow

down through the device. This promotes better heat transfer and should most certainly be explored in

further testing operations. The group, in this situation, would measure the incoming flow rates and

compare the two devices side by side, it would be expected that a greater delta temperature would be

seen in the increase tube diameter prototype. This might have some negative effects on the city water

pipeline; this idea would have to be explored before testing to ensure no damage would come to tying

this prototype into an end users city water supply line.


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14.0 Future Look Ahead

Team Fluggen would like to take this part of the report and discuss a little bit about the possible

way forward from this stage of the design. The team has accomplished a few milestones, like building

and testing our prototype and proving that it can have cost savings in the vicinity of where we wanted

them to be at the end of the day. However, further refinement of the model is required. The look ahead

will be broken down into steps, beginning with:

1) Constructing and testing prototype 2 – The model the group fabricated is functional, however

the connections are not permanent and the copper coil didn’t turn out the way the group had

originally intended it to. The first priority of the group would be to build and test the new model

with refined dimensions. The results from those tests could be compared to the original results

from the current model, and any improvements to the heat transfer characteristic would be

noted, and new cost savings would be calculated.

2) Marketability Study – A marketability study would have to be carried out to assess the market

here in NL, but also across Canada with the use of online surveys. Through this exercise, the

group could possibly attain a volunteer to hook the new refined prototype into their home to

see how the performance measures compared to those results found in the lab.

3) Approach Construction Companies – It would be a mission for Fluggen to approach local and

larger construction companies that design and build houses in urban environments, assess

whether or not a product like this could be easily included into their plumbing blue print

drawings, and determine whether or not companies would be willing to include a device like this

into their building plans.

4) Maintenance Assessment – The maintenance requirements as of right now are ill defined,

because the team did not have an accurate way of simulating this effect with experimentation. If

the new prototype were to be installed into a real home and it had real grey water moving

through it, the maintenance requirements would have to be assessed and a recommended

cleaning schedule could be put forth for the operators manual for the end product (after the

design process is finished).


43

Potential Market

Based on the results from the Fluggen model testing the concept has been proven to be

successful when used with a cold inlet water temperature of 6 degrees Celsius. Heat recovery will

decrease with increasing cold water inlet temperature therefore colder regions such as Canada will

experience the greatest energy saving with a GWHR system. In warmer climates GWHR are less effective

and are in competition with solar hot water heating which has been proven to be an effective method of

hot water energy reduction.

Potential markets for the Fluggen GWHR system are as follows:

1. R-2000 houses.

The most obvious market for GWHR systems is R-2000 houses because there owners

and designers already have an interest in energy savings. The R-2000 market is relatively small

however it would serve as starting point to expose the public to GWHR. R-2000 homes are

mainly designed to reduce space heating load while incorporating low flow fixtures and an

energy efficient water heater. The DHW use is low in these houses however the fraction of total

energy used by DHW heating is larger than in the average house.

2. Remote location market.

Remote locations with high energy costs and low potable water temperatures such as

northern Canada are an ideal market for GWHR because of their high energy cost. Domestic hot

water heating is often several times more expensive in these areas therefore the payback

periods for GWHR systems should be very short.

3. Multi-unit residential market.

Condominiums, duplexes and apartment blocks are an excellent application for GWHR systems

if the greywater plumbing is common to more than one home dwelling. With multiple units

draining greywater through the same pipe the total greywater energy available would be much

higher than a single detached house therefore the greater potential energy savings.


44

15.0 Conclusions

From this design process, it can be concluded that using a device like the one we produced here

at the university would have beneficial cost savings if used in a residential application. Implementing a

device like this one would also have positive effects on your hot water tank. The reduce load

requirements experienced by the hot water tank would prolong the life of the heating elements (for

electrical applications) and reduced maintenance requirements would be experienced by the end users.

It can also be drawn from this experience that this device can be produced for less than 300 dollars.

Keeping the model inexpensive was a key milestone for this project. It was felt by all group members as

well as the group supervisor that if the model were to have been expensive, it would not be very

marketable. With an expected life ranging from 10-15 years where the system is so passive, it could be

expected that cost savings would pay for the device and then much more for households with higher hot

water demands than seen on average. It can also be concluded that the mathematical model used to

predict these temperature differences is accurate to an acceptable degree. This can ensure that future

design alterations will provide us with accurate information before we move into testing phases.

Some improvements mentioned in the latter part of this report would certainly have to be

included and evaluated in the second round of testing if this project were to be carried further. Also, a

test house would have to be established, whose plumbing would be altered in such a way that this

device could be tested in a real life scenario. A method of observing the cost savings would have to be

created, perhaps by evaluating the power associated with a control house, with the same number of

individuals living in it having similar hot water demands.

It can also be concluded that if this project were to continue forward, a marketability survey

would have to be performed to evaluate the market for introduction of a device like this into someone’s

home. Also, a product like this might not be feasible in other countries like in Europe, where the water

consumption is much lower than that here in Canada. A feasibility study could be done, to see if the on

average higher prices seen in Europe could counterbalance the less favorable heat transfer

characteristics of the water consumption rates.


45

16.0 References

1. http://oee.nrcan.gc.ca/equipment/heating/806#storage

2. http://home.howstuffworks.com/water-heater.htm

3. http://www.canadianwaterheaters.com/en/c378144982/index.html

4. http://books.google.ca/books?id=POemMdRJ_qcC&pg=PA537&lpg=PA537&dq=average+dishwa

sher+discharge+volumes&source=bl&ots=b5cDqC-

Moa&sig=G8Gqrlg8EfgpDrQtPJRVK7wB1Qc&hl=en&sa=X&ei=omwhT7WXG-

vp0QGj48GACQ&ved=0CDAQ6AEwAQ#v=onepage&q=average%20dishwasher%20discharge%20

volumes&f=false

5. http://www.practicalenvironmentalist.com/eco-gadgets/dishwashers-energy-star-water-

efficiency-and-the-environment-a-consumer-guide.htm

6. http://www.profilecanada.com/companydetail.cfm?company=179562_Hydraulic_Systems_Limi

ted_St_Johns_NL

7. http://www.westlundpvf.com/locations/atlantic/westlund-newfoundland/

8. http://sedc-coalition.eu/wp-content/uploads/2011/07/CREEDAC-Canadian-Residential-Hot-

Water-Apr-2005.pdf

9. http://www.benjaminmoore.com/en-us/for-architects-and-designers/epoxy-coatings

10. Eslami-nejad, P., & Bernier, M. (2009). Impact of Greywater Heat

Recovery on the Electrical Demand of Domestic Hot Water Heaters.

11. Natural Resources Canada. (2005). R-2000 Standard.

12. Health Canada. (2010). Canadian Guidelines for Domestic Reclaimed Water for Use in Toilet and

Urinal Flushing.

13. See Line Group Inc. (2005). Technology Assessment Study and TRC Analysis.


46

APPENDIX A- Project Schedule


47

APPENDIX B – Technical Drawing Packages

- Final Drawing Package

- Initial Drawing Package


48


49


50


51


52

Initial Drawing Package


53


54


55


56


57

APPENDIX C – Theoretical Calculations

Appendix C1: Predicted Values Calculations Explanation

The iterative method to vary T∞, the grey water temperature acting at the surface of the coil is

described below:

- 1. From initial temperatures and volumes of water associated with the constructed model,

the energy of the potable water in the coil and the grey water in the reservoir is calculated.

Eold = Mass*Told*cp

- 2. A time-step for iterations is selected corresponding to the transit time of the coil.

Time Step = (Mass in coil) / (mass flow rate through coil)

- 3. The grey water average temperature is modified to account for the grey water coming in

from the shower and the grey water leaving at the overspill per time-step. These

temperatures are different, and if the grey water average temperature changes to reflect

this.

Eold,GW after flow = Eold GW + [(Mass in)*TGW in *cp] – [(Mass out) *Told*cp]

TGW after flow = T∞ = (Eold,GW after flow)/(MassGW * cp)

- 4. The temperature rise of a slug of potable water is calculated according to the following

equation:

(Incropera, p.472)

- 5. The energy of the slug of potable water leaving the device is subtracted from the energy

of the grey water.


58

EPotable slug = (MassPotable slug) * cp*( Tm,o- Tm,i)

EGW after potflow = Eold,GW after flow - EPotable slug

- 6. The energy lost to the environment through the reservoir side walls per time-step is

subtracted from the grey water.

qloss = (TGW after potflow) – External Environment)/Req2

Eloss to envirnoment = qloss * (timestep)

EGW after loss = EGW after potflow – Eloss to envirnoment

- 7. The new grey water temperature is reinitialized for the next time-step and return to step

1.

Appendix C2: Estimated Convection Coefficient for Potable Coil

For out constructed model,


59

K = 0.59

volflow = 0.000095

m dot = 0.095

Pr = 6.62

Di = 0.01905

Cm = 0.0762

mew = 0.001225

mew surface

temp = 0.0013

Red = 5183.256

Red dc = 2591.628

a = 1.000021

b = 1.072054

Nud = 52.68715

hi = 1631.781

Appendix C3: Comparison of Theoretical and Experimental Results

The experimental data is presented in Appendix E while the predicted values calculation

procedure is presented in C3. Through comparing both data, the following correction to the initial values

of the convection coefficients was observed to provide a better fit:

The theoretical and experimental values are shown in (APP?). Using the results of the model

tests, convection coefficients were varied from the initial estimates to better fit the data by trial and

error. The initial estimates and revised combinations of heat transfer coefficients which yield a better fit

to the data in are stated below:

Original:

‘hpot’ = 1631 (W / m2·K)

‘hgrey,flow’ = 1000 (W/ m2·K)


60

‘hgrey,idle’ = 75 (W / m2·K)

Revised:

‘hpot’ = 1631 (W / m2·K)

‘hgrey,flow’ = between 800 and 1500 (W/ m2·K)

‘hgrey,idle’ = Between 20-100 (W / m2·K)

These new values were chosen due to better fitting the data by trial and error across all

experiments. These new values are used in the theoretical model and plotted against the experimental

data in figures C1 through C10.

Theoretical & Experimental - Potable & Greywater Temperatures

Both Flowing @ 1.4 gpm

0

5

10

15

20

25

30

35

40

45

50

0 200 400 600 800 1000 1200

Time (s)

Tem

pera

ture

s (°C

)

Greywater In Greywater OutPotable Water In Potable Water OutGreywater In Experimental Experimental Grey Water OutPotable Water In Experimental Experimental Potable Water Out

Figure C1: Three 10 minute “Showers” in 40 Minutes, Shower Flow at 1.4gpm.


61

Theoretical & Experimental - Potable & Greywater Temperatures -

Both Flowing Both Flowing @ 1.4 gpm

0

5

10

15

20

25

30

35

40

45

50

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Time (s)

Tem

pera

ture

s (°C

)

Theoretical Greywater In Theoretical Greywater OutTheoretical Potable Water In Theoretical Potable Water OutExperimental Greywater In Experimental Grey Water OutExperimental Potable Water In Experimental Potable Water Out

Figure C2: Three Showers in 40 Minutes, Shower Flow at 1.6gpm.



0

5

10

15

20

25

30

35

40

45

0 200 400 600 800 1000 1200

Time (s)

Tem

pera

ture

s (°C

)


Figure C3: Three Showers in 40 Minutes, Shower Flow at 2.0gpm.


62



0

5

10

15

20

25

30

35

40

45

0 200 400 600 800 1000 1200

Time (s)

Tem

pera

ture

s (°C

)


Figure C4: Three 10 minute ‘Showers’ in 40 Minutes, Shower Flow at 2.5gpm.

Theoretical & Experimental Potable (Flowing @ 1.5gpm)

& Greywater (Idle) Temperatures

0

5

10

15

20

25

30

0 100 200 300 400 500 600

Time (s)

Tem

pera

ture

(°C

)

Potable Water In Potable Water Out Greywater

Experimental Potable Water In Experimental Potable Water Out Experimental Greywater

Figure C5: Potable Flow Only, Potable flow at 1.5gpm, grey water initially at 26°C.


63

Theoretical & Experimental Potable (Flowing @ 1.5gpm) & Greywater

(Idle) Temperatures

0

5

10

15

20

25

30

35

40

45

0 100 200 300 400 500 600

Time (s)

Tem

pera

ture

(°C

)

Potable Water In Potable Water Out Greywater

Experimental Potable Water In Experimental Potable Water Out Experimental Greywater

Figure C6: Potable Flow Only, Potable flow at 1.5gpm, grey water initially at 38°C

Multi-Stage (1) - Theoretical & Experimental Potable (Flowing @ 0.75gpm) &

Greywater (Flowing @ 1.5gpm) Temperatures

0

10

20

30

40

50

0 100 200 300 400 500 600

Time (s)

Tem

pera

ture

s (°C

)


Figure C7: Multi Stage Part 1


64

Multi-Stage (2) - Theoretical & Experimental Potable (Flowing @ 0.75gpm) &

Greywater (Flowing @ 1.5gpm) Temperatures

0

5

10

15

20

25

30

35

0 100 200 300 400 500 600

Time (s)

Tem

pera

ture

s (°C

)


Figure C8: Multi Stage Part 2

Reduced Grey Water Volume

Theoretical & Experimental - Potable & Greywater Temperatures - Both Flowing

0

5

10

15

20

25

30

35

40

45

0 100 200 300 400 500 600

Time (s)

Tem

pera

ture

s (°C

)


Figure C9: Reduced Volume Test


65

Continuous Flow - Theoretical & Experimental Potable & Greywater Temperatures

Both Flowing @ 2.5gpm

0

5

10

15

20

25

30

35

40

45

0 200 400 600 800 1000 1200

Time (s)

Tem

pera

ture

s (°C

)


Figure C10: Continuous Flow Test

These adjusted heat transfer coefficient seem to be a better fit of the data than the initial

values. The mass flow was fluctuating during some of these tests in both the simultaneous and potable

only flow cases. The inlet temperatures were seen to be fluctuating in the model test. Also, the sensors

used for the grey water test may have been influenced by their proximity to the coil as this variable was

not noted well during experimentation. These inconsistencies with the model cause scatter and

potentially bias in the data. The theoretical model seems relatively centered in the data across most

tests despite the scatter and bias.


66

APPENDIX D – Design of Experiments

Design of Experiments

The model and prototyping stage will involve the construction and testing of a proof-of-

concept device to verify actual performance characteristics. The testing phase will be

completed by running the device under different realistic flow scenarios and using the

information to verify our theoretical and optimization models. The temperatures of the flows

will be measured during regular time intervals and the results will be used to perform an

analysis.

Testing Preparation

In preparation of completing the testing phase of our project we had to establish a

construction and testing location, which we’ve discussed with Craig Mitchell in the thermal lab.

We will be using a location near the back of the room by the doors to the fluids lab so that we

have access to the hot and cold water taps. We will acquire the necessary components for

testing and these will be accessible in time for testing.

Location:

- Thermal/Fluids Laboratory in the Engineering Building at Memorial University of

Newfoundland

Purpose:

- Testing a wastewater heat recovery device in operation under different flow scenarios

to measure the heat transfer

Materials:

- 4 Thermocouples wires

- 2 Digital temperature reader

- Hot and cold water taps

- Hot and cold water hoses

Procedure:


67

2. Measure the temperature of the hot and cold water feeds to determine if they match

our predefined values:

a. Hot water -> 37 - 42⁰C (If this temperature is not at the value required, we will

either cool or heat the water until it reaches the desired value)

b. Cold water -> Vary between 3⁰C (Winter) and 10⁰C (Summer)

3. Measure the amount of water for a typical shower, bath and dishwashing load and

devise a method for storing that amount of water at the right temperature

4. Measure the flow rate of the hot and cold water feeds. This will be done by measuring

the time it takes for a tap to fill a container to a certain volume. Flow meters would be

ideal for more accurate measurements, but these would be difficult to install and

calibrate given the small size of our project.

a. If the flow rates match that required for the testing parameters, simply use

these. If not, devise a method for accurate flows using a storage reservoir and

connected hose

5. Connect the device to the hot and cold water feeds and connect the thermocouples in

the appropriate locations. This will be in the incoming and outgoing feeds for both

potable water and greywater. These locations will be determined after model

construction is complete and will be based on the optimal temperature location of the

feeds.

6. The tests will involve testing different flow conditions that would typically be seen in a

residential home such as:

a. Potable water and greywater flowing (Shower and Dishwasher)

i. Testing Type 1 – Three 10 minute showers with 5 minute breaks

1. Q = 1.5, 2, 2.5 gal/min

ii. Testing Type 2 – Continuous running for 20 minutes for Q = 2.5 gal/min

iii. Testing Type 5 – Decrease reservoir volume

iv. Testing Type 6 – Install baffles in tank

b. Potable water flow only (Sink use)

i. Testing Type 3 – Q = 1.5 gal/min

1. Reservoir temp at room temp and 40 ⁰C

c. Multi-stage flow (modular design)

i. Testing Type 4 – Two passes in parallel

1. Flow rates in half, reservoir temp of 2nd test to be greywater out

7. The transient aspect will be measured in small time intervals but will increase when the

system begins to stabilize at steady state.


68

8. We will only have access to one digital temperature reader, so we will connect

thermocouple wires in the appropriate locations and connect the temperature reader to

each one every 15 seconds or so.

a. (Note: if this time period is not sufficient to switch over the wires, we will devise

a plan to fix this.)

9. The amount of water for each type of test will be dependent on the input condition

being modelled:

a. Shower – 56 lt

b. Bath – 80 lt

c. Dishwasher load – 25 lt

10. The results will be recorded during the tests and inputted into a spreadsheet so that

numerical analysis can be performed on the results to calculate the amount of heat

transfer.

Results

The results will be recorded on the spreadsheet attached and input into excel.

Analysis

Once the temperatures have been recorded during multiple tests, we will use these to

perform an analysis on the results. With the results of our different flow scenarios we can

develop models for typical household energy savings possible depending on the hot water use.

By comparing the results using different flow rates, the use of efficient fixtures can be analyzed.

We will also examine the multi-stage design and it’s effectiveness. This will involve calculating

the coil or simultaneous heat transfer through the first section of our module and calculating

the reservoir or batch heat transfer through the second section of our module. By verifying

both of these heat transfer amounts, we can compare to the theoretical values that we

generated using our calculation spreadsheet. Verification of the cost savings associated with

our device will also be completed in comparison to our initial cost calculations.

Along with our theoretical and optimization calculations, we can use the results of our

tests to determine final sizes and arrangements. By comparing the results of actual and

theoretical we can determine the accuracy of our assumptions used in the theoretical

calculations and determine some methods for improvements. We will also be able to determine

the most feasible arrangement of our modules based on the amount of heat transfer measured

in each test.


69

APPENDIX E – Testing Results

Test 3 – Q = 1.4 gal/min

Date: March 30th, 2012

Experiment #: 3

Location:

Fluids

Lab

Module Tested: Coil

Potable Flow: 1.4 gal/min

Greywater Flow: 1.4 gal/min

Initially: Reservoir temperature at 28 ⁰C

Simulating three 10 minute showers with two 5 minute breaks

- Breaks are every 10 minutes"

Test Results:

Temperatures (⁰C)

Time (s)

Potable

Water In

Potable

Water

Out

Greywater

In

Greywater

Out ΔT pot ΔT grey

0 9.1 18 44.7 28.3 8.9 16.4

30 7.2 16 38.2 28.8 8.8 9.4

60 7 15.7 38.2 28.7 8.7 9.5

90 6.9 15.7 38.5 28.8 8.8 9.7

120 6.8 15.6 38.8 28.3 8.8 10.5

150 6.8 15.7 38.8 28.9 8.9 9.9

180 6.7 15.9 38.7 28.9 9.2 9.8

210 6.6 15.8 38.6 29 9.2 9.6

240 6.6 15.8 38.7 29 9.2 9.7

270 6.5 15.8 38.6 29 9.3 9.6

300 6.5 15.8 38.6 28.9 9.3 9.7

330 6.5 15.8 38.6 29 9.3 9.6

360 6.4 16 38.6 29.1 9.6 9.5

390 6.3 15.9 38.6 29.1 9.6 9.5

420 6.3 15.7 39.1 29.1 9.4 10

450 6.2 15.8 38.8 29 9.6 9.8

480 6.1 16 38.7 29.1 9.9 9.6

510 6.1 15.7 38.9 29.1 9.6 9.8

540 6.1 15.8 38.8 29.2 9.7 9.6

570 6 15.8 38.8 29.2 9.8 9.6


70

10 MIN 5.9 15.8 39 29 9.9 10

630 5.9 15.8 39 29.2 9.9 9.8

660 5.8 15.7 39.1 29.1 9.9 10

690 5.7 15.8 39 29.1 10.1 9.9

720 5.7 15.8 39 29.2 10.1 9.8

750 5.6 15.5 39.1 29.2 9.9 9.9

780 5.6 15.8 39 29.2 10.2 9.8

810 5.6 15.6 39 29.2 10 9.8

840 5.5 15.8 39 29.2 10.3 9.8

870 5.5 15.8 39 29.2 10.3 9.8

900 5.5 15.6 39.1 29.2 10.1 9.9

930 5.5 15.6 39 29.1 10.1 9.9

960 5.5 15.8 39 29.1 10.3 9.9

990 5.6 15.7 39 29.3 10.1 9.7

1020 5.6 15.7 39 29.2 10.1 9.8

1050 5.6 15.6 39.1 29.2 10 9.9

1080 5.5 15.7 39 29.1 10.2 9.9

1110 5.5 15.7 39.1 29.1 10.2 10

1140 5.5 15.6 39.4 29.1 10.1 10.3

1170 5.5 15.7 39.1 29.1 10.2 10

20 MIN 5.5 15.7 39 29 10.2 10

1230 5.4 15.5 39 29.2 10.1 9.8

1260 5.4 15.6 39 29 10.2 10

1290 5.4 15.7 39 29.1 10.3 9.9

1320 5.4 15.5 39 29 10.1 10

1350 5.3 15.5 38.9 29.1 10.2 9.8

1380 5.3 15.6 38.9 29.1 10.3 9.8

1410 5.3 15.6 39 29 10.3 10

1440 5.3 15.5 38.8 29.1 10.2 9.7

1470 5.3 15.5 38.9 29.1 10.2 9.8

1500 5.3 15.4 38.9 29.1 10.1 9.8

1530 5.3 15.4 38.9 29.1 10.1 9.8

1560 5.3 15.5 39 29.1 10.2 9.9

1590 5.3 15.4 38.9 29.1 10.1 9.8

1620 5.3 15.5 38.9 29 10.2 9.9

1650 5.3 15.5 38.9 29.1 10.2 9.8

1680 5.4 15.4 39 29.1 10 9.9

1710 5.4 15.5 39 29 10.1 10

1740 5.4 15.6 39 29.1 10.2 9.9

1770 5.4 15.4 39 29.1 10 9.9


71

30 MIN 5.4 15.4 38.9 29.1 10 9.8

Tci Avg Tco Avg Thi Avg Tho Avg ΔTp Avg ΔTg Avg

5.86 15.71 38.99 29.05 9.85 9.93

Potable Water Inlet/Outlet Temps

Greywater Inlet/Outlet Temps


72

Model Testing Results


Experiment #: 5

Location:

Fluids

Lab

Module Tested: Coil



Initially: Reservoir temperature at 24.5 ⁰C

Simulated three 10 minute showers with two 5 minute breaks

- Breaks are every 10 minutes

Test Results:

Temperatures (⁰C)

Time (s)

Potable

Water In

Potable

Water Out

Greywater

In

Greywater

Out ΔT pot Δ grey

0 13 20.9 36.4 24.5 7.9 11.9

30 10.7 16.5 32.9 24.3 5.8 8.6

60 10.2 16.4 32.9 24.5 6.2 8.4

90 10.2 16.8 41.8 25.4 6.6 16.4

120 10 17.1 36.2 26 7.1 10.2

150 9.7 16.6 35.4 26 6.9 9.4

180 9.7 16.3 41.8 26.7 6.6 15.1

210 9.5 16.8 42.5 26.9 7.3 5.6

240 9.4 16.8 43.3 27.2 7.4 16.1

270 9.3 17.1 44 27.6 7.8 16.4

300 9.3 16.9 44.9 28 7.6 16.9

330 9.2 16.8 45.3 28 7.6 17.3

360 9.1 17 45.5 28.2 7.9 17.3

390 9 16.9 35.6 28.9 7.9 6.7

420 8.9 16.6 40.5 28.5 7.7 12

450 8.8 16.9 38.6 28.1 8.1 10.5

480 8.7 16.8 39.3 28.4 8.1 10.9

510 8.7 16.6 40.2 28.4 7.9 11.8

540 8.6 16.7 40.8 28.4 8.1 12.4

570 8.5 16.9 41.7 28.6 8.4 13.1

10 MIN 8.4 16.9 42.2 28.7 8.5 13.5

630 5.8 14.5 40.2 28.6 8.7 11.6


73

660 5.4 14.9 41.1 28.4 9.5 12.7

690 5.3 14.8 41.1 28.2 9.5 12.9

720 5.3 14.6 41.3 28.2 9.3 13.1

750 5.2 14.8 41.2 28.1 9.6 13.1

780 5.1 14.6 41.3 28.1 9.5 13.2

810 5.1 14.8 37.5 28.4 9.7 9.1

840 5 14.7 37.8 28.3 9.7 9.5

870 5 14.6 37.8 28.2 9.6 9.6

900 5 14.6 37.6 28.2 9.6 9.4

930 5 14.3 37.7 28.1 9.3 9.6

960 4.9 14.6 37.7 28.1 9.7 9.6

990 4.9 14.5 37.9 28 9.6 9.9

1020 4.9 14.4 37.7 28.1 9.5 9.6

1050 4.9 14.5 37.8 28 9.6 9.8

1080 4.9 14.2 37.7 27.9 9.3 9.8

1110 4.9 14.5 37.8 27.9 9.6 9.9

1140 4.9 14.4 37.7 27.9 9.5 9.8

1170 4.9 14.4 37.8 27.9 9.5 9.9

20 MIN 4.9 14.4 37.7 27.9 9.5 9.8

1230 4.9 14.6 36.9 27.5 9.7 9.4

1260 4.9 14.5 37.2 27.4 9.6 9.8

1290 4.9 14.3 37.3 27.3 9.4 10

1320 4.8 14.5 37.4 27.4 9.7 10

1350 4.8 14.4 37.4 27.5 9.6 9.9

1380 4.8 14.2 37.5 27.5 9.4 10

1410 4.8 14.2 37.6 27.5 9.4 10.1

1440 4.8 14.2 37.4 27.5 9.4 9.9

1470 4.8 14.3 37.4 27.5 9.5 9.9

1500 4.8 14.4 37.4 27.5 9.6 9.9

1530 4.8 14.4 37.4 27.4 9.6 10

1560 4.8 14.1 37.2 27.5 9.3 9.7

1590 4.8 14.1 37.3 27.5 9.3 9.8

1620 4.8 14.1 37.3 27.4 9.3 9.9

1650 4.8 14.2 37.4 27.4 9.4 10

1680 4.8 14.1 37.3 27.4 9.3 9.9

1710 4.8 14.2 37.3 27.3 9.4 10

1740 4.8 14 37.3 27.3 9.2 10

1770 4.8 14.2 37.3 27.4 9.4 9.9

30 MIN 4.7 14.3 37.2 27.4 9.6 9.8


74


6.50 15.29 8.73 27.58 8.79 11.15




75



Experiment #: 7

Location:

Fluids

Lab

Module Tested: Coil

Potable Flow: 2 gal/min

Greywater Flow: 2 gal/min




Test Results:

Temperatures (⁰C)

Time (s)

Potabl

Water In

Potable

Water Out

Greywater

In

Greywater


0 5.5 16.5 38.6 25.6 11 13

30 5.2 11 39.6 23.7 5.8 15.9

60 5.2 11.4 40.2 23.2 6.2 17

90 5.1 11.5 40.7 21.5 6.4 19.2

120 5.1 11.8 41 22.1 6.7 18.9

150 5.1 12 41 22.4 6.9 18.6

180 .1 12.5 41.5 23.4 7.4 18.1

210 5.1 12.8 42.2 23.8 7.7 18.4

240 5.1 13.2 39.7 24.8 8.1 14.9

270 5 13 40.5 24.9 8 15.6

300 5 13.3 40.8 25.8 8.3 15

330 5 13.7 41.3 26.4 8.7 14.9

360 5 13.8 41.9 26.8 8.8 15.1

390 4.9 14.3 42.4 27.6 9.4 14.8

420 4.9 14.2 42.5 28 9.3 14.5

450 4.8 14.2 42.6 28.6 9.4 14

480 4.8 13.2 42.6 29 8.4 13.6

510 4.5 13.3 42.6 29.2 8.8 13.4

540 4.5 13.3 42.6 29.3 8.8 13.3

570 4.7 13.5 42.6 29.3 8.8 13.3

10 MIN 4.7 13.4 42.6 29.5 8.7 13.1

630 4.8 13.2 38.8 29.5 8.4 9.3


76

660 4.8 13.2 39.8 29.1 8.4 10.7

690 4.7 13.3 39.8 29.3 8.6 10.5

720 4.7 13.3 39.9 29.4 8.6 10.5

750 4.7 13.4 39.9 29.5 8.7 10.4

780 4.7 13.4 40 29.6 8.7 10.4

810 4.7 13.3 39.9 29.7 8.6 10.2

840 4.6 13.3 39.9 29.7 8.7 10.2

870 4.6 13.4 39.8 29.8 8.8 10

900 4.6 13.5 39.9 29.8 8.9 10.1

930 4.6 13.5 39.9 29.9 8.9 10

960 4.6 13.5 39.9 29.9 8.9 10

990 4.6 13.6 39.8 29.8 9 10

1020 4.6 13.6 39.8 30 9 9.8

1050 4.6 13.5 39.8 30 8.9 9.8

1080 4.6 13.6 39.7 29.9 9 9.8

1110 4.6 13.5 39.7 30 8.9 9.7

1140 4.6 13.6 39.7 30.1 9 9.6

1170 4.6 13.5 39.6 30.2 8.9 9.4

20 MIN 4.6 13.5 39.6 30.2 8.9 9.4

1230 4.9 13.4 38.5 30 8.5 8.5

1260 4.7 13.3 39.1 28.4 8.6 10.7

1290 4.7 13.1 39.3 29.8 8.4 9.5

1320 4.7 13.1 39.4 25.9 8.4 13.5

1350 4.7 13 39.4 25.5 8.3 13.9

1380 4.7 13.2 39.3 29.9 8.5 9.4

1410 4.7 13 39.2 29.9 8.3 9.3

1440 4.7 12.6 39.3 29.8 7.9 9.5

1470 4.7 12.6 39.4 29.8 7.9 9.6

1500 4.7 13.4 39.3 29.8 8.7 9.5

1530 4.8 13.3 39.3 29.9 8.5 9.4

1560 4.8 13.4 39.3 29.8 8.6 9.5

1590 4.8 13.5 39.3 29.9 8.7 9.4

1620 4.8 13.4 39.2 29.9 8.6 9.3

1650 4.8 13.4 39.2 29.9 8.6 9.3

1680 4.8 13.5 39.2 29.9 8.7 9.3

1710 4.8 13.5 39.2 29.9 8.7 9.3

1740 4.8 13.4 39.2 29.9 8.6 9.3

1770 4.8 13.5 39.3 29.9 8.7 9.4

30 MIN 4.8 13.6 39.3 29.9 8.8 9.4


77


4.79 13.28 40.15 28.33 8.48 11.83




78


Date: April 2th, 2012

Experiment #: 8

Location:

Fluids

Lab

Module Tested: Coil



Initially: Reservoir temperature at 17



Test Results:

Temperatures (⁰C)

Time (s)

Potable

Water In

Potable

Water Out

Greywater

In

Greywater


0 6.7 8.9 35.4 17.2 2.2 18.2

30 6.6 9.6 37.5 17.2 3 20.3

60 6.5 10.8 37.8 20.6 4.3 17.2

90 6.4 11 38 19.9 4.6 18.1

120 6.4 11.4 38.2 21.3 5 16.9

150 6.4 11.6 38.2 22.2 5.2 16

180 6.5 11.9 38.1 23.2 5.4 14.9

210 6.5 12.2 38.2 23.9 5.7 14.3

240 6.3 12.3 38.2 25.2 6 13

270 6.2 12.4 38.1 25.1 6.2 13

300 5.9 12.5 38 25.7 6.6 12.3

330 5.7 12.3 37.9 26.5 6.6 11.4

360 5.3 12.2 37.8 26.8 6.9 11

390 5.3 12.3 37.8 27 7 10.8

420 5.2 12.4 37.8 27.4 7.2 10.4

450 5.1 12.2 37.8 27.5 7.1 10.3

480 5 12.2 37.7 28.1 7.2 9.6

510 4.9 12.2 37.5 28 7.3 9.5

540 4.9 12.1 37.8 28.1 7.2 9.7

570 4.8 12.2 37.7 28.2 7.4 9.5

10 MIN 4.9 12.3 38.3 28.4 7.4 9.9

630 5 12.2 37.2 28.3 7.2 8.9


79

660 4.8 12 38 28.3 7.2 9.7

690 4.7 12 38 28.2 7.3 9.8

720 4.7 12.2 38 28.5 7.5 9.5

750 4.7 12.1 38.1 29 7.4 9.1

780 4.7 12.1 38.1 29 7.4 9.1

810 4.7 12.3 38.1 28.9 7.6 9.2

840 4.7 12.4 38.1 29 7.7 9.1

870 4.7 12.3 38.2 29.5 7.6 8.7

900 4.8 12.3 38.2 29.5 7.5 8.7

930 4.7 12.3 38.2 29.3 7.6 8.9

960 4.7 12.2 38.2 29.4 7.5 8.8

990 4.7 12.3 38.2 29.4 7.6 8.8

1020 4.7 12.5 38.2 29.9 7.8 8.3

1050 4.7 12.5 38.2 29.8 7.8 8.4

1080 4.7 12.3 38.2 29.8 7.6 8.4

1110 4.7 12.4 38.2 29.9 7.7 8.3

1140 4.7 12.7 38.2 29.7 8 8.5

1170 4.7 12.3 38.3 30.3 7.6 8

20 MIN 4.8 12.6 38.2 29.9 7.8 8.3

1230 5.2 13.2 37.8 29.7 8 8.1

1260 5 13 38.3 29.6 8 8.7

1290 5 12.8 38.4 29.4 7.8 9

1320 4.9 13 38.5 29.9 8.1 8.6

1350 4.9 13.1 38.5 30.2 8.2 8.3

1380 4.8 12.9 38.4 29.9 8.1 8.5

1410 4.8 12.8 38.5 29.9 8 8.6

1440 4.8 13 38.5 30.1 8.2 8.4

1470 4.8 13.2 38.5 30.2 8.4 8.3

1500 4.8 13 38.8 30.2 8.2 8.6

1530 4.7 12.9 38.4 30.4 8.2 8

1560 4.8 13 38.6 30.3 8.2 8.3

1590 4.7 13.1 38.4 30.3 8.4 8.1

1620 4.7 13 38.5 30.3 8.3 8.2

1650 4.7 13.2 38.5 30.5 8.5 8

1680 4.7 12.8 38.4 30.3 8.1 8.1

1710 4.7 13 38.4 30.4 8.3 8

1740 4.7 12.9 38.5 30.5 8.2 8

1770 4.7 13 38.5 30.5 8.3 8

30 MIN 4.7 13.3 38.5 30.6 8.6 7.9


80


5.12 12.35 38.11 27.97 7.23 10.14




81



Experiment #: 4

Location:

Fluids

Lab

Module Tested: Coil




Simulating continuous running with an input greywater of 38 ⁰C

Test Results:

Temperatures (⁰C)

Time (s)

Potable

Water In

Potable

Water Out

Greywater

In

Greywater


0 6.6 12.2 31.9 25.7 5.6 6.2

30 6.4 12.2 31.9 25.8 5.8 6.1

60 6.3 12.1 31.9 25.9 5.8 6

90 6.2 12 32.1 26 5.8 6.1

120 6.2 12 32.1 26 5.8 6.1

150 6 11.9 35.6 26 5.9 9.6

180 6 12.2 36.4 26.5 6.2 9.9

210 6 12.4 39.3 26.8 6.4 12.5

240 6 12.8 39.6 27.6 6.8 12

270 5.9 12.8 39.8 27.9 6.9 11.9

300 5.8 12.9 40 28.5 7.1 11.5

330 5.6 13 40.5 28.9 7.4 11.6

360 5.5 13 40.8 29.2 7.5 11.6

390 5.5 13.5 40.9 29.7 8 11.2

420 5.4 13.8 41 29.9 8.4 11.1

450 5.3 12.6 41 30 7.3 11

480 5.2 12.6 38.5 30.7 7.4 7.8

510 5.2 12.7 38.4 30.5 7.5 7.9

540 5.2 12.5 38.3 30.3 7.3 8

570 5.2 12.5 38.4 30.3 7.3 8.1

10 MIN 5.2 12.4 38.2 30.4 7.2 7.8

630 5.1 12.6 38.3 30.3 7.5 8


82

660 5.1 12.5 38.3 30.3 7.4 8

690 5.1 12.6 38.3 30.4 7.5 7.9

720 5.1 12.5 38.3 30.3 7.4 8

750 5.1 12.5 38.3 30.3 7.4 8

780 5.1 12.6 38.3 30.3 7.5 8

810 5.1 12.6 38.2 30.5 7.5 7.7

840 5.1 12.7 38.3 30.5 7.6 7.8

870 5.1 12.6 38.2 30.2 7.5 8

900 5.1 12.6 38.2 30.2 7.5 8

930 5 12.5 38.2 30.3 7.5 7.9

960 4.9 12.5 38.1 30.2 7.6 7.9

990 4.8 12.4 38.1 30.2 7.6 7.9

1020 4.8 12.3 38.1 30.1 7.5 8

1050 4.6 12.2 38 30.1 7.6 7.9

1080 4.6 12.2 38 29.9 7.6 8.1

1110 4.5 12.2 37.9 30.1 7.7 7.8

1140 4.5 12.2 38 30.1 7.7 7.9

1170 4.4 12.1 37.9 30.1 7.7 7.8

20 MIN 4.4 12 37.9 30.1 7.6 7.8


5.32 12.50 37.79 29.20 7.18 8.60



83



84

Team Fluggen


Date: April 2nd, 2012

Experiment #: 11

Location:

Fluids

Lab

Module Tested: Coil


Greywater

Flow: 1.5 gal/min


Reduced volume in reservoir, 11 lt less

Note: flow rates had to be adjusted a few times during this test

Test Results:

Temperatures (⁰C)

Time (s)

Potable

Water In

Potable

Water

Out

Greywater

In Greywater Out ΔT pot ΔT grey

0 7.1 18.9 34 24 11.8 10

30 7.2 15.3 37.9 24.7 8.1 13.2

60 7 15.7 38.3 24.9 8.7 13.4

90 7 15.8 38.4 25 8.8 13.4

120 7 15.8 38.6 25.4 8.8 13.2

150 7 15.6 33.8 26.1 8.6 7.7

180 7 15.5 35.3 25.9 8.5 9.4

210 6.9 15.4 35.3 25.9 8.5 9.4

240 6.9 15.3 36.4 25.9 8.4 10.5

270 6.9 15.4 36.9 26.1 8.5 10.8

300 6.9 15.4 36.8 26 8.5 10.8

330 6.9 15.4 36.7 26.1 8.5 10.6

360 6.9 15.4 36.7 26.1 8.5 10.6

390 6.9 16.4 36.6 26.1 9.5 10.5

420 6.8 16.7 36.5 26.2 9.9 10.3

450 6.7 16.5 36.2 26.3 9.8 9.9

480 6.5 14.6 36.2 26.3 8.1 9.9

510 6.4 14.6 36 26 8.2 10

540 6.2 13.9 36 25.5 7.7 10.5

570 6.1 13.9 36 25.4 7.8 10.6


85

10 MIN 6 13.8 35.8 25 7.8 10.8


6.78 15.49 36.40 25.66 8.71 10.74




86



Experiment #: 9

Location:

Fluids

Lab

Module Tested: Coil




Simulating modular operation with two units. Potable flow is in parallel

and therefor split in half.

For second part, use Tout greywater for tank temp

Test Results:

Temperatures (⁰C)

Time (s)

Potable

Water In

Potable

Water

Out

Greywate

r In

Greywater


0 7.1 26.4 35 25 19.3 10

30 5.8 18.3 37 26.1 12.5 10.9

60 5.4 19 37.9 26.7 13.6 11.2

90 5.4 19.2 38.3 27.3 13.8 11

120 5.3 19.5 38.7 27.1 14.2 11.6

150 5.3 19.8 39 27.3 14.5 11.7

180 5.3 20 39.1 27.6 14.7 11.5

210 5.4 20.2 39.2 27.9 14.8 11.3

240 5.4 19.3 39.3 28.3 13.9 11

270 5.4 18.5 39.3 28.5 13.1 10.8

300 5.3 18.4 39.3 28.7 13.1 10.6

330 5.3 19.3 39.3 28.9 14 10.4

360 5.3 19.5 39.3 29.2 14.2 10.1

390 5.3 19.9 39.6 29.2 14.6 10.4

420 5.3 19.8 39.6 29.4 14.5 10.2

450 5.3 20.2 39.7 29.5 14.9 10.2

480 5.4 20.1 39.8 29.9 14.7 9.9

510 5.4 20.1 39.9 29.9 14.7 10

540 5.3 20.3 39.9 30.1 15 9.8

570 5.3 20.5 39.7 30.2 15.2 9.5

10 MIN 5.3 20.4 39.7 30.3 15.1 9.4


87


5.44 19.94 38.98 28.43 14.50 10.55




88



Experiment #: 10

Location:

Fluids

Lab

Module Tested: Coil



Initially: Reservoir temperature at greywater outlet of first test (29-30) ⁰C

Simulating modular operation with two units. Potable flow is in parallel

and therefore split in half.

Test Results:

Temperatures (⁰C)

Time (s)

Potable

Water In

Potable

Water Out

Greywater

In

Greywater


0 7.3 25.6 30.2 26.6 18.3 3.6

30 6.6 19.6 30.6 26.5 13 4.1

60 6.5 18.7 30.7 26.5 12.2 4.2

90 6.6 18.3 27.2 25.6 11.7 1.6

120 6.6 18.1 27.3 25.6 11.5 1.7

150 6.6 17.7 29.1 25.6 11.1 3.5

180 6.6 17.9 29.4 25.2 11.3 4.2

210 6.6 17.7 29.5 25.2 11.1 4.3

240 6.6 17.6 29.5 25.2 11 4.3

270 6.6 17.6 29.7 25.2 11 4.5

300 6.6 17.6 29.7 25.2 11 4.5

330 6.6 17.6 29.8 25.2 11 4.6

360 6.5 17.6 29.9 25.2 11.1 4.7

390 6.5 17.5 29.8 25.1 11 4.7

420 6.5 17.3 29.8 25.1 10.8 4.7

450 6.4 17.2 30.1 25.3 10.8 4.8

480 6.9 17.3 29.9 25 10.4 4.9

510 6.3 17.1 29.9 25 10.8 4.9

540 6.3 17.2 29.9 25 10.9 4.9

570 6.2 17 29.9 25 10.8 4.9

10 MIN 6.2 17.2 30.9 24.9 11 6


89


6.55 18.07 29.66 25.39 11.51 4.27




90


Date:

March 30th,

2012

Experiment #: 6

Location:

Fluids

Lab

Module

Tested: Coil


Greywater

Flow: 0 gal/min


Simulating batch flow with low potable flow and no greywater flow

Test Results:

Temperatures (⁰C)

Time (s)

Potable

Water In

Potable

Water

Out

Greywater

Tank Greywater Out ΔT pot

ΔT

grey

0 5.5 12.3 26.3 24.2 6.8 -2.1

30 5.5 12.4 25.5 24.1 6.9 -1.4

60 5.5 12.1 24.8 23.9 6.6 -0.9

90 5.4 11.9 24.8 23.8 6.5 -1

120 5.4 11.6 23.9 23.7 6.2 -0.2

150 5.4 11.5 23.6 23.8 6.1 0.2

180 5.4 11.3 22.9 23.6 5.9 0.7

210 5.4 11.1 22.7 23.3 5.7 0.6

240 5.3 11 22.2 23.3 5.7 1.1

270 5.3 10.8 21.9 23.4 5.5 1.5

300 5.3 10.6 21.5 23.2 5.3 1.7

330 5.2 10.3 21.1 23.2 5.1 2.1

360 5.2 10.3 20.9 23.2 5.1 2.3

390 5.2 10.1 20.6 23.2 4.9 2.6

420 5.1 10 20.3 23.3 4.9 3

450 5.1 9.8 19.9 23.2 4.7 3.3

480 5 9.7 19.7 23.1 4.7 3.4

510 5 9.5 19.5 23 4.5 3.5

540 4.9 9.4 19 23.2 4.5 4.2

570 4.9 9.2 18.9 23.2 4.3 4.3


91

10 MIN 4.9 9.1 18.7 23.1 4.2 4.4

Tci Avg Tco Avg Thi Avg Tho Avg ΔTp

Avg

ΔTg

Avg

5.23 10.67 23.43 21.84 5.43 1.59




92



Experiment #: 12

Location:

Fluids

Lab

Module

Tested: Coil


Greywater

Flow: 0 gal/min


Simulating batch flow with low potable flow and no greywater flow

Test Results:

Temperatures (⁰C)

Time (s)

Potable

Water In

Potable

Water

Out

Greywate

r Tank Greywater Out ΔT pot ΔT grey

0 7.5 22 36.2 37.5 14.5 -1.3

30 7.5 20.7 36 37.6 13.2 -1.6

60 7.5 22 35.6 40 14.5 -4.4

90 7.5 20.4 35.7 40.6 12.9 -4.9

120 7.6 20.2 34.8 40.3 12.6 -5.5

150 7.6 19 34.6 40.2 11.4 -5.6

180 7.6 19.6 33.9 39.9 12 -6

210 7.7 18.9 33.2 39.9 11.2 -6.7

240 7.7 18.9 33.1 39.8 11.2 -6.7

270 7.6 18.3 32.3 39.7 10.7 -7.4

300 7.6 18.1 31.8 39.5 10.5 -7.7

330 7.6 17.9 31.5 39.5 10.3 -8

360 7.5 17.7 31.1 39.5 10.2 -8.4

390 7.5 17.2 30.5 39.3 9.7 -8.8

420 7.4 16.9 30 39.2 9.5 -9.2

450 7.3 16.6 29.4 39 9.3 -9.6

480 7.2 16.3 28.9 39 9.1 -10.1


93

510 7.1 16 28.5 39 8.9 -10.5

540 7 15.8 28 38.9 8.8 -10.9

570 6.9 15.3 27.5 38.9 8.4 -11.4

10 MIN 6.8 15 27 38.7 8.2 -11.7

630 6.7 14.6 26.4 38.5 7.9 -12.1

660 6.6 14.5 26 38.41 7.9 -12.41

690 6.5 14.1 25.4 38.4 7.6 -13

720 6.5 13.9 25.2 38.3 7.4 -13.1

750 6.9 13.7 24.8 38.3 6.8 -13.5

780 6.3 13.5 24.5 38.2 7.2 -13.7

810 6.2 13.2 24 38.1 7 -14.1

840 6.2 13.1 23.8 38 6.9 -14.2

870 6.2 12.9 23.5 38 6.7 -14.5


7.13 16.88 29.77 39.01 9.75 -9.23



94



95

APPENDIX F – Construction and Testing Pictures


96


97


98

APPENDIX G – Design Criteria Table

Design Criteria Notes

Weight - What can 2 people safely carry?

- Approximate weight of hot water tank?

Volume of Waste Water &

Potable Water

- Typical discharge information for devices under

consideration, including flow rates, discharge volumes,

and discharge temperatures

- Spreadsheet calculations for optimized volume ratio

(waste to potable), ranges

- Ultimate size of reservoir (roughly size of hot water tank?)

- Dimensions of a standard doorway

- Dimensions of a hot water tank

- Footprint not too big – limited space in houses?

- Height of unit – not too tall, typical ceilings, height of hot

water tank.

Reservoir

- Existing reservoirs – can we utilize already existing

reservoirs i.e. hot water tanks, oil drums, water barrels

etc.

- Thermal conductivity of reservoir material

- Corrosion (or other reactions) considerations

- Mechanical properties i.e. strength, toughness, ductility

- Use of membranes – to prevent leaks in case of

puncture/failure of reservoir

- Other considerations regarding material selection i.e. cost,

procurement

- Construction considerations i.e. is it easy to cut or drill,

will epoxies and sealants adhere to it, etc.

- Reservoir will have to be emptied for maintenance,

removal purposes – need valves for this purpose?

Internal Tubes

- Material selection

- Thermal conductivity

- Corrosion / reaction considerations

- Clogging

- Dimensions (inner & outer diameters)

- Bending radius before kink

- Heat treatments to improved bending radius before kink?

- Cost, procurement

- Formability

- Possibility of puncture or damage

- Joining considerations

- Pressure drops through tubes

- Bypass the unit? May need valves to allow for water


99

flowing through tubes to bypass unit

- Need to ensure tubes can be emptied for

maintenance/removal

Hook Up

- Sewage regulations, codes, inspections required?

- Traps

- Sealants, joints

- Bypass – allow waste water to by pass unit – valve

- Sediment filter


- Cost, procurement

- Mechanical properties

- Temperature control – servo valve

Solid Sediment Filtration

- Sizes of sediments

- Shape, consistency of sediments

- Filter maintenance (reusable, one time use?)

- Access to filter

- Clogging potential

- Filter versus no filter (cost?)

Sanitation Control

- Jointless tubes/quality control of joints

- Antibacterial fluid medium between potable water and

waste water – conductivity

- UV filtration

- Bacteria types/mold/fungus

- Temperature of hot water tank – mixing valve to allow hot

water tank to be set at high temp, then cooled to safe

temp before sent to distribution pipes

- Spill kit, risk mitigation, external drain incase of spill

Functionality

- Clogging mitigation

- Fluid flow characteristics through unit

- Water stagnation

- Standard valves

Maintainability

- Cleaning

- Filters

- Useful life of components

- Emptying waste water and potable water

- Shut off valves

Efficiency

- Benchmarks of existing technology

- Multi-stage

- Tube routing


- Thermal conductivity of materials

- Volumes/flow rates optimized

- Water storage considerations

- Computed optimizations

Simplicity - No leaks

- Few or no mechanical/electrical components – passive


100

device

- Simple installation/hook up procedure

- Construction should be relatively simple

Safety/Risk

- No sharp protruding edges

- Potable water contamination is not allowed

- Hook up to hot water tank

- Spill containment

- Joint protection

Environmental Impact - Material selection – harmful to environment?

- Spill impact analysis

Cost

- Material Selection

- Electricity costs

- Rate of return for owner

- Construction methods, materials

- Overall unit cost

Robustness - Mechanical protection of joints

- Will the reservoir protect any internal components

- Mounting considerations i.e. straps, bolts, ties, etc.

Insulation - Exterior reservoir insulation

- Pipe insulation for hook up, lines coming from devices to

unit


101

APPENDIX H – Screening and Evaluation Matrices


102

APPENDIX I – Final Concept Sketches

Concept A


103

Concept F


104

Concept L


105

Concept M (Final Concept)

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Final Design Report Rev 1 - Residential Wastewater Heat … · 2012-04-05 · Team Flüggen –...

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