April 11, 2011
Prepared for:
Dr. Eric Bibeau, P. Eng.
MECH 4692
University of Manitoba
Department of Mechanical and Manufacturing Engineering
`
Design Project
Final Report
Jordan Friesen, C.E.T. 7599269
MECH 4692 - Design Project April 11, 2011
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Table of Contents List of Figures ................................................................................................................................................ ii
List of Tables ................................................................................................................................................. ii
Executive Summary ....................................................................................................................................... 1
Assumptions .................................................................................................................................................. 2
Model Description......................................................................................................................................... 3
Original Energy Loads ................................................................................................................................ 3
Renewable Energy Systems ...................................................................................................................... 5
Biomass Hot Water Boiler ..................................................................................................................... 7
Geothermal/Free Cooling ................................................................................................................... 10
Wind Turbine ...................................................................................................................................... 13
Overall System Control ....................................................................................................................... 16
Transportation .................................................................................................................................... 18
Design Justification ..................................................................................................................................... 19
Bed and Breakfast System Design ........................................................................................................... 19
Transportation ........................................................................................................................................ 20
Results and Conclusion ............................................................................................................................... 21
Works Cited ................................................................................................................................................. 25
Appendix A – Spreadsheet Calculations ..................................................................................................... 26
Biomass Combustor ................................................................................................................................ 26
Groundwater Cooling .............................................................................................................................. 26
Wind Turbine .......................................................................................................................................... 27
Greenhouse Gas Production ................................................................................................................... 27
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List of Figures Figure 1 - Yearly energy profile on a monthly average (kWhr) ..................................................................... 5 Figure 2 - System overview ........................................................................................................................... 6 Figure 3 - Design heating and hot water load ............................................................................................... 7 Figure 4 - Heating load hourly breakdown for each month ......................................................................... 8 Figure 5 - Cooling load hourly breakdown for each month ........................................................................ 11 Figure 6 - Groundwater aquifer around Winnipeg [6] ................................................................................ 12 Figure 7 - Hourly electrical demand for each month .................................................................................. 13 Figure 8 - ReDriven Power Inc 20kW wind turbine power curve [8] .......................................................... 15 Figure 9 - ReDriven Power Inc 50kW wind turbine power curve [9] .......................................................... 15 Figure 10 - Heating and cooling system schematic ..................................................................................... 17 Figure 11 - Biomass heating output and wood usage per month .............................................................. 21 Figure 12 - Electrical load distribution throughout the year ...................................................................... 22
List of Tables Table 1 - Energy loads for bed and breakfast [2] .......................................................................................... 3 Table 2 - Average Monthly Load Distribution ............................................................................................... 4 Table 3 - Wood boile loading and pumping power....................................................................................... 9 Table 4 - Cooling load breakdown .............................................................................................................. 11 Table 5 - Weibull shape and scale factors for wind analysis [7] ................................................................. 14 Table 6 - Site wind speeds at varying hub heights ...................................................................................... 15 Table 7 - Turbine cost comparison .............................................................................................................. 16 Table 8 - Toyota Prius and VW Jetta fuel comparison ................................................................................ 18 Table 9 - Summery of costs and savings ..................................................................................................... 19 Table 10 - GHG production of original and new design .............................................................................. 20 Table 11 - Summary of the heating, cooling and electrical loads for the system design ........................... 23 Table 12 - GHG production summer of original and new design................................................................ 24
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Executive Summary This design report intends to develop a renewable energy alternative to the prototypical housing design in Winnipeg, Manitoba. The design focuses on a bed and breakfast located south of Winnipeg that has been designed using traditional energy systems such as natural gas heating, electrical cooling and hot water and gasoline for transportation. The new system design utilizes wood fired hot water boilers, groundwater cooling and wind turbines to produce renewable energy for the bed and breakfast. The total system is expected to cost $348,000 to install with an annual operating cost of $9,000 and an annual cost savings of $36,700. This yields a payback for the system in less than 20 years and can be decreased to 15 years with rebates of over $50,000 available from MB Hydro. The design also reduces the overall greenhouse gas emissions of the bed and breakfast by 215 tons of CO2 which is over 96% of the original greenhouse gas production. The cost of the greenhouse gas reduction is $1,620 per ton of CO2. The design of the renewable energy systems focuses on commercially available technologies to reduce cost and increase the reliability of the renewable energy systems. The report separates the building load analysis from the transportation aspect because the loads are not interdependent and can therefore be treated separately.
Through modeling of the energy load from the house, the biggest factor for greenhouse gas emissions are the two natural gas furnaces used to heat the house and greenhouse. The new design replaces the natural gas furnaces with two wood burning hot water boilers from Portage & Main. These boilers produce enough thermal energy for both the heating and hot water loads throughout the year totalling 1.11 GWhr. The biomass boilers will cost a total of $59,300, and produce a yearly savings of $30,500. The annual wood and maintenance cost for the boilers is expected to be $5,500. The cooling system relies on the assumption that the bed and breakfast will be located over the large aquifer on the east side of the Red River south of Winnipeg. This aquifer will provide cold water that is pumped into the house and greenhouse to provide up to 121 kW of cooling. The groundwater system is expected to cost $22,500 with an operating and maintenance cost of $1,000 per year. The electrical saving compared to the traditional air source heat pump is $1,700 per year. Finally, two ReDriven 20kW wind turbines were selected for the project. The wind turbines are where the majority of the costs lie, with a total system cost of $266,000 for the two turbines. The annual maintenance costs are estimated at $2,700 with an annual electricity savings of $4,600. The two wind turbines produce a total of 76,600 kWhr of electricity over the year resulting in 68% of the electrical energy required for the bed and breakfast.
The two vehicles used for transportation were also considered in the design. The car and the truck combine to produce 7.9 tons of CO2 throughout the year. These emissions could be reduced by switching to hybrid electric vehicles. The report looks at replacing the car with a Toyota Prius to further reduce greenhouse gas emissions. The Prius would reduce the greenhouse gas emissions by 1.44 tons of CO2, at a cost of about $28,000. For the Prius, the cost per ton of CO2 reduction is $19,500, which is over ten times the cost of CO2 reduction for the building systems portion of the project. As a result, the purchase of new vehicles for the bed and breakfast to reduce the greenhouse gas emissions is not recommended based on the comparison with the building systems. If however, the owners are considering purchasing a new vehicle for other reasons, a hybrid electric vehicle is recommended as compared to purchasing a regular gas or diesel vehicle.
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Assumptions Within this report several assumptions have been made to allow for a design to be reached. These assumptions need to be addressed to ensure that all assumptions can be justified to justify the final design. The assumptions are listed and justified below.
• House and greenhouse require the same proportion of heating and cooling throughout the year. o To determine the heating load on the house and greenhouse, the load was distributed
throughout the year using degree days. The heating and cooling applied to the house and greenhouse are proportional to the yearly consumption of natural gas, 20% for the house and 80% for the greenhouse.
• HVAC equipment efficiencies o It was assumed that the original design allowed for a 95% efficient natural gas furnace which is a
standard high efficiency furnace that is commercially available. o The air conditioning system was assumed to have a COP of 4.5. Most air conditioning systems
have a SEER rating between 13 and 16. A COP of 4.5 is between a 15 and 16 SEER rating which is a reasonably efficient air conditioning system.
o The fan for the forced air furnace runs independently of the heating or cooling system throughout the year to ventilate the residence.
o Heating and cooling coil heat transfer coefficients are assumed to be 300 W/m2·k. • Ground water temperature
o It was assumed that the ground water temperature is the same as the ground temperature or the average yearly temperature. The ground water temperature was assumed to be 3°C [1].
o It was assumed that the bed and breakfast will be built over the major aquifer that runs underneath the south end of Winnipeg and that the water will be accessible for free cooling. The aquifer runs on the east side of the Red River south of Winnipeg.
• Lighting distribution o It was assumed that the amount of lighting used in a month is inversely proportional to the
number of hours of sunlight in a given month. Thus the more sunlight the less artificial light. • Wood Furnace
o It was assumed that the flu stack temperature will be 250°C. The manufacturer stated that the flu stack temperature is expected to be around 400°F (205°C). 250°C was selected to be conservative.
• Costs o It is assumed that the Canadian and American dollars are on par so any pricing given in USD has
been converted to CND at 1 to 1. • GHG
o Only GHG’s produced by the systems will be considered in the analysis. Life cycle analysis of the manufacturing and processing of the equipment will not be considered in this report.
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o It was assumed that the CO2 produced by the burning of wood is not considered as GHG because it is renewable CO2 that was collected in the wood within the last 200 years and is therefore part of the normal CO2 cycle.
Model Description The model description of the energy system was developed to determine the best way to adapt renewable systems for the bed and breakfast. First the original loads where broken down over the year to see where the non-renewable energy was being used and how to best apply the renewable energy systems. Then an overview of the total renewable system is given to show all the systems for the bed and breakfast and how they interact. Finally each renewable system is described and details for the model used are given. Transportation is discussed at the end of the model description as it is a separate topic from the bed and breakfast.
Original Energy Loads The energy load of the building and occupants was given in the project definition. All of the electric, natural gas and fuel requirements were stated on a consumption per year basis. These various loads needed to be broken down into a monthly average for each month of the year, and each day in a given month with a typical energy distribution for variable consumption loads. Table 1 shows the loads given in the project definition.
Table 1 - Energy loads for bed and breakfast [2] Energy Type Function Energy Units Electricity Fridge 18000 kWhr/yr Electricity Freezer 18000 kWhr/yr
Electricity Lighting 18000 kWhr/yr Electricity Appliances 18000 kWhr/yr Electricity Computers 18000 kWhr/yr Electricity Air Circulation 18000 kWhr/yr Electricity A/C 36000 kWhr/yr Electricity Hot Water 36000 kWhr/yr Natural Gas House Heating 20000 m3/year Natural Gas Greenhouse Heating 80000 m3/year Gasoline Car 1000 L/year Gasoline Truck 2400 L/year
The loads given in Table 1 assume that no renewable energy is applied and all the loads take into account efficiencies of the appliances that are using the energy. This means that the actual energy required to perform the function needs to be accounted for when changing the source of energy for any of the different functions. To elaborate further, a standard natural gas furnace is about 95% efficient, which means that to heat the house only 95% of the natural gas is required; the other 5% is wasted. Any renewable system that would displace the
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natural gas furnaces would need to supply the same amount of energy as 95% of the 100,000 m3 of natural gas listed in Table 1.
With the standard loads only supplied on a yearly basis, the distribution of the loads throughout the year is not known. The loads must be broken down into average monthly loads as shown in Table 2.
Table 2 - Average Monthly Load Distribution
Month Fridge kWhr
Freezer kWhr
Lighting kWhr
Appliances kWhr
Computers kWhr
Fan kWhr
A/C kWhr
Hot Water kWhr
House Furnace m3 NG
Green House Furnace m3 NG
Car L gas
Truck L gas
Jan 1500 1500 1947.2 1500 1500 1500 0 3000 4158 16631 83 200
Feb 1500 1500 1768.4 1500 1500 1500 0 3000 2942 11769 83 200
Mar 1500 1500 1532.2 1500 1500 1500 0 3000 2149 8597 83 200
Apr 1500 1500 1308.7 1500 1500 1500 0 3000 1550 6198 83 200
May 1500 1500 1101.3 1500 1500 1500 168 3000 660 2640 83 200
Jun 1500 1500 1005.5 1500 1500 1500 2355 3000 342 1368 83 200
Jul 1500 1500 1053.4 1500 1500 1500 18168 3000 64 258 83 200
Aug 1500 1500 1228.9 1500 1500 1500 14804 3000 64 258 83 200
Sep 1500 1500 1452.4 1500 1500 1500 505 3000 604 2415 83 200
Oct 1500 1500 1691.8 1500 1500 1500 0 3000 1268 5071 83 200
Nov 1500 1500 1899.3 1500 1500 1500 0 3000 2270 9080 83 200
Dec 1500 1500 2011.0 1500 1500 1500 0 3000 3928 15713 83 200
For the most part, the monthly loads in Table 2 are divided evenly across 12 months from the loads given in Table 1. The heating and cooling loads were divided up using a degree-day method. The degree days were taken from [1]. The lighting load was assumed to be inversely proportional to the daily sunlight. With the monthly average data, an equivalent energy graph was created to determine the distribution of the energy use over the whole year as seen in Figure 1.
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Figure 1 - Yearly energy profile on a monthly average (kWhr)
To generate an average 24 hour day for each month, some of the loads where considered to be evenly distributed where others vary with the time of day. For example the appliance load does not specify which appliances are used in the home, there is probably a washing machine and a drier and other typical household appliances but the load profile cannot be known. For this reason the appliance load is assumed to have a distribution of 65% of the load from 8am to 8pm distributed evenly with the remaining 35% distributed over the rest of the time. The energy from the lighting is distributed over the day with the highest usage during the morning and evening hours and is scaled by the average hours of sunlight per month [1] .
Renewable Energy Systems To completely remove the bed and breakfast from the grid is not a viable option economically due to the massive electrical storage that would be required for the bed and breakfast to operate without interruption. To go completely off grid either requires a very large amount of storage for when electrical generation is low and demand is high, or the owner would have to limit demand to whenever he could generate the power required. This can be accomplished for small houses if all residents take part in demand management. Requiring guests to limiting demand at the bed and breakfast will provide an uncomfortable experience and is therefore not recommended. Finally, Manitoba Hydro provides almost 100% renewable power, and with the ability to reverse meter on electrical, adding electrical storage to the system does not make sense environmentally or economically. Given that the bed and breakfast will be connected to the grid, reverse metering will be utilized so that the owner can use MB Hydro as storage for the electrical system so if the electrical generator generates more electricity than is demanded , it will be sold back to Hydro at $0.06/kWhr. This is the same rate paid for the electricity so the only cost of storage is the capital for the reverse meter, which is about $500.This will provide guests with the most comfortable experience.
There were three main areas of consideration given in the request for proposal from the owner. These three areas were the natural gas furnace for the house and greenhouse, the electrical loads for the buildings and hot
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water, and the fossil fuels used for transportation. The given loads have been broken down in the above section to establish energy requirements throughout the year. To reduce the GHG emissions from these systems, and achieve the design goals set out by the client, the design will consider two biomass hot water boilers, a ground water based free cooling strategy, a wind turbine and alternative vehicle technology for transport. Figure 2 shows an overview of the systems used for the residence.
Figure 2 – Renewable energy system overview
The three main systems used for the house are a wood burning hot water heating system, a ground source water cooling system, and wind turbines used to generate electrical energy to offset the load purchased from MB Hydro.
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Biomass Hot Water Boiler To model the heating system for the B&B the first thing that is required is a load breakdown and conversion to energy requirements. The load breakdown for the biomass system will include both the heating load, and the hot water load to remove the hot water element from the electrical system. The heating load was broken down using the degree day method, such that each month has a certain number of degree days below 18°C. The degree days for each month were divided by the total number of degree days below 18°C and then multiplied by the yearly heating load. The yearly heating load was converted from natural gas to kWhr of energy assuming a furnace efficiency of 95%. The hot water load was assumed to be constant over the entire year, and as such the given electrical load, assuming 100% efficiency, was divided evenly between each day and each hour in the day. The final heating load profile including hot water heating is shown in Figure 3.
Figure 3 - Design heating and hot water load
As the graph shows, the heating load varies greatly throughout the year. To match the above heating loads, Dr. Bibeau’s Biomass Combustor Analysis spread sheet was modified to allow for the calculation of the required wood throughout the year [3]. The biomass model takes the higher heating value of Poplar at 19,380kJ/kg, and performs an ultimate analysis of combustion on the wood to determine the heat of the flu gas. The flu gas is then sent through a heat exchanger with a given efficiency f 15% to determine the heat transferred to the hot water heating system. Dr. Bibeau’s spread sheet was utilized because it uses varying specific heat values throughout the calculation and iterates to find a more accurate result than a constant specific heat method or a proximate analysis that does not consider how each molecule affects the heat output. The main steps and formulas used in the ultimate analysis are given below:
Total heating value of the fuel:
𝑄𝑡𝑜𝑡 = 𝐻𝐻𝑉𝑑𝑟𝑦 ∗ �̇� (𝑘𝑊)
Heating value after losses:
𝑄𝑎𝑐𝑡𝑢𝑎𝑙 = 𝑄𝑡𝑜𝑡 ∗ (1 − 𝜂𝐻𝑋)
Mass flow rate of the flu gas based on the ultimate analysis:
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𝑚𝐹𝐺 = 𝑚𝐶𝑂2 +̇ 𝑚𝑂2 +̇ 𝑚𝑁2 +̇ 𝑚𝐻2𝑂̇̇
The heat recovered in the heat exchanger is:
𝑄𝑟𝑒𝑐 = �̇�𝐶𝑃Δ𝑇 = �𝑚𝐶𝑂2 ∗ 𝐶𝑝𝐶𝑂2 +̇ 𝑚𝑂2 ∗ 𝐶𝑝𝑂2 +̇ 𝑚𝑁2 ∗ 𝐶𝑝𝑁2 +̇ 𝑚𝐻2𝑂̇ ∗ 𝐶𝑝𝐻2𝑂� ∗ (𝑇𝑓𝑙𝑢 − 𝑇𝑠𝑡𝑎𝑐𝑘)
The results of the analysis output a heat output in kW and kWhr/month. To determine the amount of wood required for a month, a VBA script was written to compare the heat required for the month to the heat output for the month from the combustor. The script varied the mass of wood input into the system until the heat required matched the heat output by the system. The maximum heating demand was determined for each month and used to calculate the monthly wood requirement in kg and the maximum theoretical wood flow rate in kg/s that needs to be feed into the wood furnace. The flow rate was also determined using a VBA iteration script. The maximum heating demand was determined from Figure 4 below.
Figure 4 - Heating load hourly breakdown for each month
One of the main challenges of the system is the large fluctuation in heating and hot water loads that the greenhouse and bed and breakfast require for operation throughout the year. The combined heating and hot water load required is 1.11 GWhr over the entire year. With the load distribution of required heating and hot water, the maximum demand for heating is in January with a power of 340 kW required. The maximum demand in the winter is very large compared to the minimum demand over the summer where only 4.1 kW is required for hot water usage. This large variation in load does not lend itself well to a single boiler. Boilers tend to operate at good efficiencies when loaded above 50%. To use one boiler is not recommended given the variable load. To meet the varying demand throughout the year, two wood boilers have been selected. These boilers will need to be staged manually to provide good efficiency of wood usage throughout the year. The two boilers selected are both Portage & Main hot water wood boilers. The selected hot water boilers are model ML 30 and
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ML 54 and are capable of producing 60 kW (200,000 BTU/hr) and 290 kW (1,000,000 BTU/hr) respectively [4]. This balance of the large and small boilers allows for the maximum demand to be met in January as well as on the small heating load in the summer for hot water relatively efficiently and with the least amount of soot and ash produced. The load distribution, and the wood required for each boiler can be seen throughout the year in Table 3.
Table 3 - Wood boile loading and pumping power
The table shows the proposed distribution of load between the ML 54 and the ML 30. The loading shows that the ML 54 is utilized well throughout the winter months with a maximum loading of 95% and a minimum loading of 36%. The minimum loading in October may not operate at the rated efficiency, however the load is too large for the ML 30 and so the load must be distributed this way. Other reasons that the Portage & Main outdoor furnaces where chosen is that they are manufactured locally in Southern Manitoba, and they offer a limited 25 year warranty on the ML 54and ML 30 [4].
Using wood to heat the house, greenhouse and hot water system saves a substantial amount of money and GHG’s each year. The ML 54 water furnace costs $20,000 to purchase, and the ML 30 costs $7,900. The pricing for the Portage and Main furnaces where quoted by Portage & Main over the phone. While these are not insignificant costs, the size of the furnaces are commercial usage size, especially the ML 54. The installation cost for the system is approximated at 75% of the cost of the equipment. This cost includes the additional air-to-liquid heat exchangers that will be needed in the house and greenhouse forced air furnaces as well as the heat exchanger for the hot water system and all the associated piping. The installation also includes a portion of the control system that is required for the forced air heating system. Another consideration is pumping the water between the boilers and the house and greenhouse. Since the system is an independent system, with no utility backup, it is recommended that a parallel redundant pumping system be utilized. This will require two pumps and a lead-lag controller to control which pump is running and cycle between the pumps so that they maintain similar running hours. The redundant pumping system is recommended so that if there is a pumping failure, the house heating system will not be affected. With a greenhouse and a bed and breakfast, the heating system needs to be robust as a failure would be very costly to business and anything growing in the greenhouse. With these considerations in mind, the total cost of the biomass heating system is estimated at $60,000. Using a
Month Heating Demand ML 54 ML30 ML 54 Wood ML 30 ML 54 Wood ML 30 ṁ water Combined(kWhr/day) max (kW) (kW) (kW) (kg/s - AU) (kg/s - AU) (kg/month) (kg/month) (kg/s) Pump P(kW)
Jan 8,121 338.4 275.5 62.9 0.0294 0.00672 6.11 1.39 5.3712 0.620Feb 6,346 264.4 264.4 - 0.0282 - 5.31 0.00 4.1971 0.484Mar 4,244 161.8 161.8 - 0.0189 - 3.94 0.00 2.5690 0.296Apr 3,153 131.4 131.4 - 0.0140 - 2.81 0.00 2.0852 0.241May 1,358 56.6 - 56.6 - 0.00607 0.00 1.31 0.8979 0.176Jun 773 27.2 - 27.2 - 0.00294 0.00 0.69 0.4318 0.085Jul 99 4.1 - 4.1 - 0.00047 0.00 0.13 0.0652 0.013Aug 99 4.1 - 4.1 - 0.00047 0.00 0.13 0.0652 0.013Sep 1,289 34.7 - 34.7 - 0.00574 0.00 1.19 0.5513 0.108Oct 2,517 104.9 104.9 - 0.0112 - 2.38 0.00 1.6647 0.327Nov 4,581 190.9 190.9 - 0.0205 - 4.12 0.00 3.0297 0.350Dec 7,661 319.2 246.5 72.7 0.0264 0.00775 5.45 1.61 5.0666 0.585
Biomass Load Distribution and Pump Requirements
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wood based system will eliminate the need for natural gas displacing all 100,000 m3 of natural gas that the original design called for. Assuming that natural gas costs $0.305/m3, the annual savings is $30,500 [5]. There is also and an annual operating cost in terms of wood, as well as maintenance and electrical usage for the pumps and fan. The wood usage of the year is estimated at 31.5 metric tonnes of wood. Assuming a cost of $100/tonne or about $150/cord the annual wood costs are about $3,150 or a tenth of the natural gas consumption. The anticipated annual operating cost of the pump and fan, and the cost of maintenance is 3% of the total cost, or $1,800/year. The total system cost is $60,000 with an annual savings of $25,550 dollars. Figure 3 below shows the consumption of wood on a monthly basis over the year.
Geothermal/Free Cooling The original design was to use a geothermal system to supplement the heating load and provide cooling during the summer months. The geothermal system was modeled to produce 40 kW of heating in the winter to offset the biomass system, and produce 31 kW of cooling in the summer. After looking into an open loop geothermal system, it was apparent that using groundwater at 3°C would be able to provide enough cooling without a heat pump. Also considering that the biomass boilers would be capable of taking the entire heating load, it was decided that the geothermal system was not required. This decision reduced the overall energy consumption by almost 40% from over 180,000 kWhr/year to 112,000 kWhr/year. The original geothermal design did not consider the coefficient of performance (COP) of the air conditioning unit and was therefore too small to handle the entire cooling load. Instead of redesigning the geothermal system, a groundwater cooling system will be used instead taking advantage of the cold groundwater.
To get the actual cooling load for the bed and breakfast, a COP for the air conditioning unit had to be assumed. Based on at seasonal energy efficiency rating of between 15 and 16, a COP of 4.5 was chosen. The COP relates the input electrical power, to the cooling load by the following formula:
𝐶𝑂𝑃 =𝑘𝑊𝑐𝑜𝑜𝑙𝑖𝑛𝑔
𝑘𝑊𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑖𝑡𝑦
With a COP selected, the cooling load needed to be broken down by months, and then for a typical day each month. The given cooling load for the year was 36,000 kWhr, this load was broken down using the degree day method, where the cooling load was proportional to the number of degree days above 18°C through June, July and August. There was a small load in September that was redistributed through the other three months because it was very small in comparison. If the system is used into September, it should not affect the results drastically because the design assumes that there is cooling throughout June. June probably will only need cooling in the latter portion, and as such the balance should even out. The breakdown of the cooling load is given in Table 4.
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Table 4 - Cooling load breakdown
With the monthly cooling load, the maximum daily demand was determined by breaking the monthly load down into a typical day for each month. Figure 5 below shows the breakdown of the cooling load for each month over a 24 hour period.
Figure 5 - Cooling load hourly breakdown for each month
With the cooling load requirements determined, the groundwater cooling system can be designed. The free cooling system will consist of a pump that runs at a constant speed to provide ground water to cool the house and greenhouse throughout the summer. The cooling load for the building is very large, needing almost 35 tons of cooling on the hottest days in July. With the ground source cooling loop, the only cost for the system, once installed, is the cost of to run the pump. The pump could be run on a VFD to modulate the cooling, however the energy savings do not justify the added cost or complexity on a 5hp pump. The design assumes that the bed and breakfast will be located above the aquifer that runs beneath Winnipeg. Two well are used, one to draw the fluid into the cooling system and one to inject the warmed fluid back into the ground. Given the large water table and aquifer that is beneath the ground, the small amount of heat added will get carried away and should have little effect on the temperature of the aquifer. The aquifer can be seen in Figure 6.
A /C E lec tric al CoolingM onth (k W hr) (kWhr/month)Jun 2,523.36 11,355.14 Jul 18,168.22 81,757.01 A ug 15,308.41 68,887.85
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Figure 6 - Groundwater aquifer around Winnipeg [6]
To model the free cooling system from the groundwater source, a few simple formulas were used.
To model the heat transfer to the building are:
𝑄 = �̇�𝐶𝑝Δ𝑇𝜂𝐻𝑋
To model the pump:
�̇� =�̇�𝑔𝐻𝜂𝑝𝑢𝑚𝑝
To find the size of the heat exchangers the maximum demand of 121 kW or 35 tons of cooling was used. The cooling coils used assumed a heat transfer coefficient of 300 W/m2·K, a water side temperature rise of 5°C and air side temperatures of 33°C inlet and 15°C leaving. The equation used to find the heat exchanger areas for the house and greenhouse was:
𝑞 = 𝑈𝐴Δ𝑇𝐿𝑀𝐹
Where:
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Δ𝑇𝐿𝑀 = (𝑇𝐻𝑜 − 𝑇𝐶𝑖) −𝑇𝐻𝑖 − 𝑇𝐶𝑜
ln �𝑇𝐻𝑜 − 𝑇𝐶𝑖𝑇𝐻𝑖 − 𝑇𝐶𝑜
�
To find the heat transfer surface area for the cooling coils, it was assumed that the house required 20% and the greenhouse 80% of the cooling load which was based on the distribution of the heating requirements. This analysis leads to a coil heat transfer area for the house and greenhouse of 5m2 and 19m2 respectively.
The free cooling system needs two cooling coils, a positive displacement pump, and controls for both the house and greenhouse furnace. These components lead to a system cost of $22,500. This includes two wells drilled to 50m at $100/m for drilling and wells. It also includes $5,000 for the positive displacement pump required to pump the water, and an installation cost of $7,500 based on 50% of the capital costs of the system. The annual operating cost is estimated at $450 for maintenance. The pump is expected to run for 3 months of the year to provide cooling, yielding an electrical requirement of 7,820 kWhr. The electrical requirement is already captured in the electrical model for the wind turbine, so it will not be considered as a cost here as some of the electrical load will be taken by the wind turbines discussed in the next section.
Wind Turbine In order to develop a model with which to choose which wind turbine(s) to purchase, both the wind power and household requirements must be determined. With the heating and cooling systems for the house designed, the total electrical load was determined from the data given in the request for proposal and the changes made during the heating and cooling designs. The electrical loads were broken down into loads that are assumed to be constant over the entire year. These constant loads include the computers, furnace fans, fridge and freezer. The lighting and appliance loads are the only varying loads as described earlier in the report. The hourly breakdown in the electrical load for each month can be seen in Figure 7.
Figure 7 - Hourly electrical demand for each month
8.00
10.00
12.00
14.00
16.00
18.00
20.00
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Elec
tric
al D
eman
d (k
W)
Hour
JanuaryFebruaryMarchAprilMayJuneSeptemberOctoberNovemberDecemberJulyAugust
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The electrical load is higher in the summer months of June, July, and August due to the groundwater cooling pump. The other months vary in base loading due to the variable frequency drive on the heating system pump. One of the main design decisions is that the house will remain connected to the MB Hydro electrical grid and use reverse metering throughout the year. What this means is that if the selected wind Turbines cannot produce enough power to meet the demand; the owner will buy power from MB Hydro. If the selected wind turbines produce more power than the demand, the grid will be used as a storage system by selling the excess power back to MB Hydro at a rate of $0.06/kWhr. The reverse metering means that no battery storage is required, and the owner does not have to manage the electrical demand of their guests.
With the electrical demand modeled throughout the year, the next model required is a wind model for the site. Wind data for the site was gathered from the Canadian Wind Energy Atlas for southern Manitoba. The atlas provides Weibull shape and scale factors for approximate site location which are shown in Table 5.
Table 5 - Weibull shape and scale factors for wind analysis [7]
Period Mean Wind Speed Mean Wind Energy Weibull shape parameter (k)
Weibull scale parameter (A)
Annual 6.14 m/s 220.25 W/m2 2.01 6.93 m/s
Winter (DJF) 6.62 m/s 263.00 W/m2 2.11 7.47 m/s
Spring (MAM)
5.96 m/s 199.13 W/m2 2.03 6.73 m/s
Summer (JJA) 5.21 m/s 130.94 W/m2 2.07 5.89 m/s
Fall (SON) 6.49 m/s 252.63 W/m2 2.07 7.33 m/s
The wind data from Environment Canada is listed at a height of 50m. The height of the wind turbines selected for this project come with tower heights ranging from 18m to 36m. This means that the wind speed needs to be adjusted for the height difference using the formula:
Where V(Z2) is the velocity of the desired height, Z01 and Z02 are the relative surface roughness of the location. The relative roughness of the measurement data was assumed to be at an airport with a roughness factor of 0.1m and the building site is assumed to be surrounded by fields with a roughness of 0.05m. From the nominal wind speeds given, the wind speeds as the varying hub heights were found and can be seen in Table 6.
)/ln()/60ln()/ln()/60ln()()(
01102
0220112 ZZZ
ZZZZVZV =
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Table 6 - Site wind speeds at varying hub heights
With the wind modeled at the site, a turbine needs to be selected. Two turbines were looked at for this project, a 20 kW and 50 kW peak turbines from ReDriven Power Inc. The power curves for these turbines are given in Figures 8 & 9.
Figure 8 - ReDriven Power Inc 20kW wind turbine power curve [8]
Figure 9 - ReDriven Power Inc 50kW wind turbine power curve [9]
Season Vm (50m) Vm(18m) Vm(24m)Vm(30m) Vm(36m)Yearly 6.14 5.2 5.5 5.7 5.9Winter (DJF) 6.61 5.6 5.9 6.1 6.3Spring (MAM) 5.94 5.1 5.3 5.5 5.7Summer (JJA) 5.21 4.5 4.7 4.8 5.0Fall (SON) 6.49 5.5 5.8 6.0 6.2
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With the wind data and turbines the power output for each wind turbine at the various hub heights were evaluated. The wind speed for each quarter was applied on each of the power curves to get the power output. Table 7 below shows the results for all the turbine combinations.
Table 7 - Turbine cost comparison
Turbine
20 kW 50 kW
18m kWhr/year 38296.8 75072 Cost $ 81,217.50 $ 161,070.00 $/kWhr $ 2.12 $ 2.15
24 kWhr/year 40048.8 80980.8 Cost $ 86,677.50 $ 167,895.00 $/kWhr $ 2.16 $ 2.07
30m kWhr/year 42554.4 85773.6 Cost $ 101,010.00 $ 183,592.50 $/kWhr $ 2.37 $ 2.14
36m kWhr/year 46363.2 99504 Cost $ 112,612.50 $ 195,877.50 $/kWhr $ 2.43 $ 1.97
From the comparison table of the turbines, it seems that the best turbine is the 50kW turbine at a height of 36m. While this turbine does have the lowest cost per kWhr, it was not selected for this project. To lower the cost of the system, as well as the visual impact, two 20kW turbines at 18m are proposed for the bed and breakfast. This solution provides a $33,000 capital cost reduction, and will still provide 68% of the total yearly electrical load. This is the least expensive option to meet the 50% electrical displacement requirement.
With two 20 kW turbines, the total cost for the turbines and towers is $162,435 [8]. Also, required for the turbine is the electrical equipment to rectify and invert the DC signal to provide useable 60Hz electricity for the bed and breakfast and a reverse metering electrical meter to allow for connection to the grid. The additional electrical equipment is estimated at $15,000, and the installation is estimated at 50% of the capital cost resulting in another $88,720. The total capital cost for the wind turbine is $266,150. Given that the two turbines produce 76,600 kWhr/year, the electrical savings is $4,600 per year.
Overall System Control The overall heating and cooling system is shown in Figure 10 below. It consists of a heating controls for both the house and greenhouse furnace, heated floors in both the house and greenhouse to provide stable heat and some storage, and cooling controls for both furnaces. The system also includes a heat exchanger to heat the domestic water in the hot water tank and redundant pumps for the heating system to reduce risk of a system failure in the winter as there is no backup for the biomass heating system.
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Figure 10 - Heating and cooling system schematic
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Transportation Transportation is an issue that was dealt with separately from the bed and breakfast because there is no real connection between the two systems. The data given for the owners vehicles was given as 1,000L/year for the car and 2,400L/year for the truck. No data was given as to what type of vehicles, so it was assumed that the car was a sedan with an average fuel consumption of 10L/100km, and the truck was assumed to consume 16L/100km. The fuel economies were used to determine distances travelled for each vehicle so an analysis could be performed on alternative vehicles with better fuel economies. The distance for each vehicle was calculated using the formula:
𝑑𝑖𝑠𝑡 = 𝐿𝑦𝑒𝑎𝑟/(𝐿
100𝑘𝑚)
The average distance for the car is 10,000 km/year and for the truck 15,000 km/year.
At the moment, hybrid electric vehicles are the only real alternative to fossil fuel based vehicles. In the car segment there are many gas/electric hybrid vehicles to choose from such as the Toyota Prius, Honda Insight, Ford Fusion Hybrid, and so on. In the truck segment there is only one hybrid electric truck that I could find being the GMC Sierra. Another option to the Hybrid vehicle is just to purchase a more efficient vehicle.
If we take an example of two fuel efficient vehicles, the Toyota Prius and VW Jetta, we can compare the cost of the reduction in fuel consumption. The two cars are shown in Table 8 below [10], [11].
Table 8 - Toyota Prius and VW Jetta fuel comparison
The cost per Liter of fuel save was calculated as:
$𝐿𝑠𝑎𝑣𝑒𝑑
=𝐶𝑜𝑠𝑡
(1000𝐿 − 𝐹𝑢𝑠𝑒𝑑)
This analysis provides an idea of how much it costs for fuel savings. Another tool is to look at cost per GHG reduction which has not be look at so far in this report but will be tackled in the Design Justification section below.
Given the data, it is recommended that the vehicle situation be left as is due to the high cost on new vehicles. However, if the owner is in the market for a new vehicle, the Toyota Prius is probably the best choice of a sedan in terms of fuel savings.
Car Avg (L/100km) Distance Fuel Used (L) Cost $/L SavedPrius 3.8 10000 380 28000 45.16$ Jetta 5.7 10000 565 24000 55.17$
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Design Justification To justify the overall design and recommendation two main tools will be used. These tools are payback period for the capital investment, and cost per GHG reductions. These tools have been selected to evaluate the design to provide justifications for the design decisions discussed above. For this section the design for the bed and breakfast will be evaluated as a single system, and transportation will again be discussed as a separate topic.
Bed and Breakfast System Design To evaluate the building systems for the bed and breakfast, first the payback will be looked at and finally the GHG reductions and the cost for those reductions. In the Model Description above all the costs for the individual systems were discussed. Table 9 summarizes the results of the system costs.
Table 9 - Summery of costs and savings
In the cost summery table, the annual savings are based on the baseline values given in original request for proposal. For example the biomass boilers annual savings are based on the amount of natural gas that was supposed to be purchased in the original design times $0.305/m3 for natural gas [5]. The annual operating costs for the biomass boilers are based on the wood consumption over the year at an estimated wood price of $100/ton and an estimate maintenance cost of $1,800/year. To calculate the system payback, a present value model was used. The formula for the present value of an annuity is given as:
𝑃𝑉 ∗ (1 + 𝑖)𝑁 + 𝑝𝑚𝑡 ∗(1 + 𝑖)𝑁 − 1
𝑖= 0
Where PV is the present value of the annuity, pmt is the annuity (annual saving minus operating costs), i is the monthly interest rate and N is the number of months. The annual interest rate for the project was estimated at 5%. The monthly interest rate is then 0.41% and was calculated as follows:
(1 + 𝑖𝑚)12 = 1 + 𝑖𝑦
Using excels built in present value function, the present value of the annuity has greater value then the capital cost after 20 years. The value of the annuity after 20 years is calculated to be $350,500 which is about $2,500 more than the system cost. Now a 20 year payback is not ideal, but it is in the range of a lot of renewable energy systems and is therefore an acceptable value.
With an acceptable payback period, the reduction in GHG emissions for the design must also be considered. In the new design, the wood for heating used does not produce any long term CO2 because the wood is all
Annual Annual CostSystem Total Cost Operating Cost SavingsBiomass 59,325.00$ 5,342.25$ 30,500.00$ Wind 266,152.50$ 2,661.53$ 4,595.62$ Cooling 22,500.00$ 894.49$ 1,720.34$ Total 347,977.50$ 8,898.26$ 36,815.96$
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renewable CO2 and is considered part of the natural CO2 cycle. Also, GHG production during the manufacturing of the equipment and the shipping will not be considered in this analysis. With these limitations in mind, Table 10 shows the GHG’s produced in the original design verses the new design.
Table 10 - GHG production of original and new design
The value used for the GHG production from MB Hydro is from [12], and the value for natural gas is based on typical combustion of CH4. The only GHG produced by the new design is 0.21 tons from the purchased electricity from MB Hydro. The reduction is GHG’s is basically the total 215 tons produced in the original design, most of which is from the combustion of natural gas.
With the GHG reduction and total system cost, the cost per ton of GHG reduction can be found. This is calculated as:
𝐶𝑜𝑠𝑡𝐺𝐻𝐺𝑟𝑒𝑑
=$348,000215 𝑡𝑜𝑛
=$1,620
𝑡𝑜𝑛 𝐺𝐻𝐺𝑟𝑒𝑑
Transportation As previously mentioned in the Model Description section, the purchase of a new car and truck is not recommended. To justify this recommendation, the cost for GHG reduction of the house systems will be compared to the cost for GHG reduction if the owner were to purchase a Toyota Prius and not use the existing car. The evaluation is based on a Prius only because it has the biggest improvement in fuel economy. The original design called for 1,000L of gasoline to be used in one year by the owners’ car. Assuming an efficiency of 10L/100km for the car, the fuel saving for a Prius would be 620L of gas. To calculate the GHG’s produced by the extra gas, the following calculation was used:
𝐺𝐻𝐺𝑝𝑟𝑜𝑑 =620𝐿𝑔𝑎𝑠
1000 𝐿𝑚3
∗ 744.7𝑘𝑔𝑚3 ∗ 3.123
𝑘𝑔𝐶𝑂2𝑘𝑔𝑔𝑎𝑠
= 1,442 𝑘𝑔𝐶𝑂2 = 1.44 𝑡𝑜𝑛𝐶𝑂2
Now the cost per ton of GHG reduced is calculated in the same way as above, with the cost of the Prius as $28,000 [10].
𝐶𝑜𝑠𝑡𝑇𝑜𝑛𝐶𝑂2𝑟𝑒𝑑
=$28,000
1.44 𝑇𝑜𝑛𝐶𝑂2=
$19,444𝑇𝑜𝑛𝐶𝑂2
kg CO2 Totals(Ton CO2)MB Hydro 6 Ton/GWhr 0.18 GWhr 1080Natural Gas 2.74 kg CO2/kg 78000 kg 213720Wind 0 kg/kWhr 76593.6 0MB Hydro 6 Ton/GWhr 3.5.E-02 GWhr 212.6 Natural Gas 2.74 kg CO2/kg 0 kg 0Wood 0 kg CO2/kg 35,625 kg 0
Original Design
New Design
GHG/unit Energy
215
2.13E-01
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Comparing the $19,444 per ton of CO2 reduction to $1,620 for the building systems, it becomes obvious that capital should be put towards reducing the GHG’s from the house first. If you want to purchase fuel efficient vehicles, wait until commercially available, fully electric vehicles are available and then use the wind energy or MB Hydro to charge the car and you will reduce GHG production to almost zero for the bed and breakfast. Another recommendation to reduce GHG emissions is to use the car more often, especially when the truck is not required.
Results and Conclusion The idea behind this project was to use renewable energy to make as close to an off-grid bed and breakfast as possible considering both design complexity, economics of ownership and greenhouse gas emissions. The proposed design does not use an entirely off-grid design for the electrical load given that MB Hydro is almost 100% renewable energy as it is and can be used as storage and backup. The design does remove the bed and breakfasts dependence on fossil fuels for building and water heating. The only fossil fuels left are those to power the car and the truck that are owned by the bed and breakfast. The fossil fuels produced by the two vehicles cannot be completely removed because commercially available fully electric vehicles are not available yet. As such Hybrid vehicles were considered, but the cost of GHG reduction is prohibitive.
Moving on to the results of the design for the bed and breakfast facilities, the design utilizes two staged biomass hot water boilers, a groundwater cooling system and two 20kW wind turbines. The two biomass boilers are Portage & Main models ML 54 and ML 30 and produce 290 kW and 60 kW thermal power respectively. The biomass heating system is estimated to cost $59,500. The biomass boilers produce 1.11 GWhr of thermal energy per year using 35.6 tons of wood. The heating output and wood used per month is shown in Figure 11.
Figure 11 - Biomass heating output and wood usage per month
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0
50,000
100,000
150,000
200,000
250,000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Woo
d (k
g -w
et)
Ener
gy (k
Whr
)
Month
Heat
Wood
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The heat energy produced, and wood consumption match the heating hot water demand for the house and the greenhouse throughout the year, and both boilers are utilized to maximize their efficiency by keeping them loaded between 50 and 90%. Another consideration for installing the biomass heating system is that MB Hydro offers rebates for natural gas reduction of $0.30/m3 saved up to 50% of the total cost of the system [13]. This rebate is not taken into consideration in this report as it would have to be approved by MB Hydro, but the design does qualify and should result in a $30,000 rebate further reducing the capital cost and making the payback more favourable.
The cooling system for the house and greenhouse was a major load on the electrical system in the original design. From the original design of an air source heat pump, my first approach was to use a ground source heat pump. A geothermal system was considered to supplement the heating system in the winter, and provide the cooling in the summer. This design was not pursued because of the large electrical load that it consumed and because with a very cool groundwater system, the cooling could be obtained without a heat pump. This design decision drastically reduced the energy consumption and the capital of the system. The groundwater cooling system uses a pump to extract groundwater from a well, and pass it through an air-to-liquid heat exchanger in the house and greenhouse furnaces. A 5hp pump is required and will be run at a constant speed through the cooling months with control valves at each coil to control the outlet air temperature. The groundwater cooling system is expected to cost $22,500 with an annual operating cost of $950 per year. The yearly electrical saving from the system is expected to be $1,675 per year versus the convention air conditioning unit. For this design to work, the bed and breakfast must be built over the aquifer that runs on the east side of the Red River, south of Winnipeg.
The electrical load is broken down between the load that is supplied by the wind turbine and the load that is supplied by MB Hydro. The two wind turbines are ReDriven Power Incorporated’s 20 kW turbines, and produce an average of 38,300 kWhr of electricity each per year with a cost of $266,000. Figure 12 shows the distribution throughout the year of the electrical energy distribution between the turbine and utility versus the total load.
Figure 12 - Electrical load distribution throughout the year
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Ener
gy (k
Whr
)
Month
Electrical
Wind Electric
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From the load distribution it can be seen that on average the wind turbines never produce more power than is required to meet the load, but consistently produce as much or more power than is purchased from MB Hydro. Depending on how aggressive the owner wants to be, he could add another turbine of the same size and cover almost his entire load throughout the year. This is not recommended though because of MB Hydro’s renewable energy sources and very inexpensive energy prices. Also, the number of turbines could be reduced which would lead to a faster payback period but would not meet the requirement of 50% of the electrical load provided by the bed and breakfast systems.
With the results for all the three major systems discussed, the overall system needs to be addressed. The three major systems for the bed and breakfast and how they meet the energy loads are summarized in Table 11.
Table 11 - Summary of the heating, cooling and electrical loads for the system design
The total system cost is estimated to be $348,000 including all three new systems with a payback period of less than 20 years. This payback period can be further reduced using incentives from MB Hydro. The design would have to be evaluated by MB Hydro, and pre-approved to qualify for the incentives by with an electrical incent of $0.20/kWhr saved and a natural gas incentive of $0.30/m3 saved, the design should qualify for a $50,900 rebate from Hydro [13]. If this rebate is taken into consideration the payback period is reduced to 15 years.
The total design does not recommend any changes to the transportation system currently used, and as such will not have an effect on the system cost. The vehicles will however be the main source of GHG production for the bed and breakfast now. The summery of GHG production for the Bed and Breakfast for the original and new designs are shown in Table 12.
Electrical Heat Cooling Wind Electric Hydro Biomass Wood Groundwater Water FlowMonth (kWhr) (kWhr) (kWhr) (kWhr) (kWhr) (kWhr) (kg - wet) Cooling (kWhr) (kg/s)Jan 9,573 229,152 0 7142 2,431 229152 7500 0 0Feb 8,394 161,785 0 6451 1,943 161785 5312.5 0 0Mar 8,918 119,891 0 6250 2,668 119891 3937.5 0 0Apr 8,374 86,257 0 6048 2,326 86257 2812.5 0 0May 8,397 38,540 0 6250 2,148 38540 1312.5 0 0Jun 10,658 19,949 11355 5472 5,186 19949 687.5 11355 0.92Jul 10,974 3,058 81757 5654 5,319 3058 125 81757 6.40Aug 11,149 3,058 68888 5654 5,495 3058 125 68888 5.39Sep 8,417 35,413 0 6768 1,649 35413 1187.5 0 0Oct 9,100 71,210 0 6994 2,106 71210 2375 0 0Nov 9,193 125,201 0 6768 2,425 125201 4125 0 0Dec 9,611 216,170 0 7142 2,469 216170 7062.5 0 0Yearly 112,759 1,109,683 0 76,594 36,165 1,109,683 36,562 0 0
LoadMonthly Energy
Supply
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Table 12 - GHG production summer of original and new design
As can be seen from the above table, the reduction in GHG’s is very substantial and the majority of the CO2 produced is now by the vehicles. In the original design, the natural gas furnaces were the main source of the GHG’s.
Given a payback period of less than 20 year and a greenhouse gas reduction of 215 tons per year both justifies the design presented and validates the recommended actions to client to reduce his carbon footprint and “go green”.
Energy kg CO2 Totals(Ton CO2)MB Hydro 6 Ton/GWhr 0.18 GWhr 1080Natural Gas 2.74 kg CO2/kg 78000 kg 213720Gas 3.1225 kg CO2/kg 2532 kg 7906Wind 0 kg/kWhr 76593.6 0MB Hydro 6 Ton/GWhr 3.6.E-02 GWhr 217.0 Natural Gas 2.74 kg CO2/kg 0 kg 0Wood 0 kg CO2/kg 36562.5 kg 0Gas 3.1225 kg CO2/kg 2531.98 kg 7906
Original Design
GHG/unit
223
8.12New Design
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Works Cited [1] The Weather Network. (2011) Statistics: Winnipeg The Forks, MB, Canada. [Online].
http://www.theweathernetwork.com/statistics/summary/cl5023262
[2] Dr. Eric Bibeau, "Design Project: Off-Grid Winnipeg Bed and Breakfast," University of Manitoba, Winnipeg, 2011.
[3] Dr. Eric Bibeau. (2011) Combustor Analysis. Excel Spread Sheet.
[4] Portage & Main Wood Boiler. (2011, January) Portage & Main Outdoor Water Furnaces. [Online]. http://www.portageandmainboilers.com/pdf_brochures/P&MWoodFurnace2010BW.pdf
[5] MB Hydro. (2011, Feb.) Current Natural Gas Rates. [Online]. http://www.hydro.mb.ca/regulatory_affairs/energy_rates/natural_gas/current_rates.shtml
[6] Natural Resource Canada. (2003, Mar.) The Atlas of Canada. [Online]. http://atlas.nrcan.gc.ca/site/english/maps/freshwater/distribution/groundwater
[7] Environment Canada. (2008, July) Canadian Wind Energy Atlas. [Online]. http://www.windatlas.ca/en/nav.php?field=E1&height=50&season=ANU&lat=49.7+&lon=-97.1+&postal=&no=35
[8] ReDriven Power Inc. ReDriven Power. [Online]. http://www.redriven.ca/products/20kw-wind-turbine/
[9] ReDriven Power Inc. ReDriven Power. [Online]. http://www.redriven.ca/products/50kw-wind-turbine/
[10] Toyota Canada. (2011) 2011 Prius. [Online]. http://www.toyota.ca/toyota/en/vehicles/prius/specifications/capacity
[11] Volkswagen Canada. (2011) All-New 2011 Jetta. [Online]. http://www.vw.ca/ca/en_ca/new_models/jetta/technical_specifications.detail.1.0.html
[12] Manitoba Hydro. (2009) Manitoba Hydro's 2009 Greenhouse Gas Summary. [Online]. https://hydro.mb.ca/environment/greenhouse_gas/greenhouse_gas_summary_2009.pdf
[13] MB Hydro. (2011) Incentives. [Online]. http://www.hydro.mb.ca/your_business/custom_measures/incentives.shtml
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Appendix A – Spreadsheet Calculations All calculations for this report can be viewed in the excel spreadsheet that accompanied the report. A short list of formulas used for major calculations are given below.
Biomass Combustor Total heating value of the wood:
𝑄𝑡𝑜𝑡 = 𝐻𝐻𝑉𝑑𝑟𝑦 ∗ �̇� (𝑘𝑊)
Useable heating value:
𝑄𝑎𝑐𝑡𝑢𝑎𝑙 = 𝑄𝑡𝑜𝑡 ∗ (1 − 𝜂𝐻𝑋)
Mass fractions:
𝑌𝑖 =𝑚𝚤̇�̇�𝑡𝑜𝑡
Mass flow rate of flu gas:
�̇�𝐹𝐺 = 𝑚𝐶𝑂2 +̇ 𝑚𝑂2 +̇ 𝑚𝑁2 +̇ 𝑚𝐻2𝑂̇̇
Heat recovered from the flu gas:
𝑄𝑟𝑒𝑐 = �̇�𝐶𝑃Δ𝑇 = �𝑚𝐶𝑂2 ∗ 𝐶𝑝𝐶𝑂2 +̇ 𝑚𝑂2 ∗ 𝐶𝑝𝑂2 +̇ 𝑚𝑁2 ∗ 𝐶𝑝𝑁2 +̇ 𝑚𝐻2𝑂̇ ∗ 𝐶𝑝𝐻2𝑂� ∗ (𝑇𝑓𝑙𝑢 − 𝑇𝑠𝑡𝑎𝑐𝑘)
Groundwater Cooling Coefficient of Performance:
𝐶𝑂𝑃 =𝑘𝑊𝑐𝑜𝑜𝑙𝑖𝑛𝑔
𝑘𝑊𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑖𝑡𝑦
Calculate mass flow of water:
𝑄 = �̇�𝐶𝑝Δ𝑇𝜂𝐻𝑋
Work of the pump:
�̇� =�̇�𝑔𝐻𝜂𝑝𝑢𝑚𝑝
Calculate size of the coil:
𝑞 = 𝑈𝐴Δ𝑇𝐿𝑀𝐹
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Δ𝑇𝐿𝑀 = (𝑇𝐻𝑜 − 𝑇𝐶𝑖) −𝑇𝐻𝑖 − 𝑇𝐶𝑜
ln �𝑇𝐻𝑜 − 𝑇𝐶𝑖𝑇𝐻𝑖 − 𝑇𝐶𝑜
�
Wind Turbine Velocity change for hub height difference:
Monthly Energy Output:
𝐸𝑚𝑜𝑛𝑡ℎ = 𝑃 ∗ 𝑁𝑑𝑎𝑦 ∗ 24 ℎ𝑟
Cost per kWhr:
𝐶 =𝐶𝑎𝑝𝑖𝑡𝑎𝑙𝐸𝑦𝑒𝑎𝑟
Greenhouse Gas Production GHG production:
𝐺𝐻𝐺𝑘𝑔 = 𝑉𝑜𝑙𝑓𝑢𝑒𝑙 ∗ 𝜌𝑓𝑢𝑒𝑙 ∗𝑘𝑔𝐶𝑂2𝑘𝑔𝑓𝑢𝑒𝑙
Cost of GHG reduction:
𝐶𝐺𝐻𝐺 =𝐶𝑎𝑝𝑖𝑡𝑎𝑙𝐺𝐻𝐺𝑡𝑜𝑛𝑠
)/ln()/60ln()/ln()/60ln()()(
01102
0220112 ZZZ
ZZZZVZV =
