7/31/2019 HVAC FInal Report
1/42
Project Building Analysis
Final Report #3
7/31/2019 HVAC FInal Report
2/42
TABLE OF CONTENTS
EXECUTIVE SUMMARY ........................................................................................ Page 3
BUILDING DESCPRITION ...................................................................................... Page 4DESIGN CONDITIONS ............................................................................................ Page 8
Inside Air Temperatures .................................................................................... Page 8Supply Air Temperatures ................................................................................... Page 9
THERMAL ANALYSIS .......................................................................................... Page 10
Determination of Heating and Cooling Loads ................................................. Page 10
Determination of Building Airflows ................................................................ Page 17Determination of Duct System......................................................................... Page 23
Determination of System Load ........................................................................ Page 29Comparison to eQUEST Computer Modeling ................................................. Page 30
SUMMARY OF RESULTS ..................................................................................... Page 30
REFERENCES ......................................................................................................... Page 33
APPENDIX I ............................................................................................................ Page 34
APPENDIX II ........................................................................................................... Page 36APPENDIX III .......................................................................................................... Page 40
TABLE OF FIGURESFigure 1. Building Plan View ..................................................................................... Page 5
Figure 2. South Facing Wall ....................................................................................... Page 5
Figure 3. North Facing Wall ....................................................................................... Page 6
Figure 4. Ceiling and Roof Diagram........................................................................... Page 6Figure 5. Wall Detail (Top View) ............................................................................... Page 7
Figure 6. Wall Detail (Side View) .............................................................................. Page 7
Figure 7. South Wall Detail (Side View) .................................................................... Page 7Figure 8. Wall Representative Section ...................................................................... Page 10
Figure 9. Ceiling Representative Section.................................................................. Page 11
Figure 10. Window Geometry .................................................................................. Page 13
7/31/2019 HVAC FInal Report
3/42
TABLE OF TABLES
Table 1. Thermal Resistances ..................................................................................... Page 8
Table 2. Heat Gain for Winter .................................................................................... Page 9Table 3. Total Winter Thermal Loads ......................................................................... Page 9
Table 4. Conductive Thermal Loads ......................................................................... Page 10Table 5. Window Thermal Loads ............................................................................. Page 11
Table 6. Occupancy Chart......................................................................................... Page 12
Table 7. Equipment Chart ......................................................................................... Page 12
Table 8. Internal Thermal Loads ............................................................................... Page 13Table 9. Total Summer Thermal Loads .................................................................... Page 14
Table 10. Absolute Temperatures ............................................................................. Page 15Table 11. Average Wall Pressure Coefficient........................................................... Page 16Table 12. Wind Pressure ............................................................................................ Page16
Table 13. Total Pressure Difference ......................................................................... Page 16
Table 14. Infiltration Flow Rates for Components ................................................... Page 16
Table 15. Infiltration Flow Rates .............................................................................. Page 17Table 16. ASHRAE 62.1 Required Outside Airflow Rate ....................................... Page 17
Table 17. Building Required Outside Airflow Rate ................................................. Page 17
Table 18. Supply Airflow Rates ................................................................................ Page 18Table 19. Controlling Ratio ...................................................................................... Page 19
Table 20. Building Airflows ..................................................................................... Page 19
Table 21. Percentage of Supply Airflow Contributing to Infiltration ....................... Page 19
Table 22. Duct Size ................................................................................................... Page 21Table 23. Fitting Type............................................................................................... Page 22
Table 24. Pressure Drop Values................................................................................ Page 22
Table 25. Supply Duct Pressure Drop ....................................................................... Page 23Table 26. Supply Duct Fitting Loss Coefficient ....................................................... Page 23
Table 27. Supply Duct Damper Angles .................................................................... Page 24
Table 28. Return Duct Pressure Drop ....................................................................... Page 24
7/31/2019 HVAC FInal Report
4/42
7/31/2019 HVAC FInal Report
5/42
condensation produced in the air-handling unit was calculated to be 10.2 lbm/hr. The system-
heating load was calculated to be 19,555 Btu/hr (1.6 tons).
The building was analyzed using an energy analysis computer program, called eQUEST. The
energy simulation program provided the LS-D: Building Monthly Loads Summary and SS-D:Building HVAC Load Summary reports. The LS-D report provided a maximum heating laod of
8,283 Btu/hr, which is lower, then the calculated 19,555 Btu/hr. The SS-D report provided a
maximum cooling load of 236,754 Btu/hr, which is slightly lower, then the calculated 276,777
Btu/hr.
BUILDING DESCIPTION
The commercial building type is a conventional wood frame structure built on a concrete slab.
It is divided into four sections, three 1600 square foot rooms for a health club, a coffee house,
and a bookstore, and a 1000 square foot machinery room. The plan view of the building is
shown below, Figure 1.
Figure 1. Plan View (not to scale, doors and windows not shown)
hi k b i k h
7/31/2019 HVAC FInal Report
6/42
The back (north) side of the building has two doors located on either side of the machinery room,
as shown in Figure 3, below. The door type used for these doors is foam insulated steel slabswith metal slab in a steel frame.
Figure 3. North Facing Wall
In this report, to simplify calculations the roof is considered negligible. The roof has a
continuous ridge vent located at the top, shown in Figure 4 so the air in the attic is assumed to beequivalent to the outside temperature.
7/31/2019 HVAC FInal Report
7/42
Figure 5. Wall Detail (top view) Figure 6. Wall Detail (side view)
7/31/2019 HVAC FInal Report
8/42
DESIGN CONDITIONS
Inside Air Temperatures
The winter thermal load calculations are based on the worse case scenario, where the outsidetemperature is a constant heating dry bulb design temperature, which was found on Table 4-7B
in the HVAC textbook for Portland, OR, and there are no internal thermal loads. The inside
temperature of the building during the winter is set at 70oF. The design temperature for this
building is 22oF based on the heating dry bulb at 99.6%.
The summer load calculations are based on an hour-by-hour time series. The hourlytemperatures were found by where, Tdesign is the cooling dry bulb design temperature, % is the percentage of daily range, and
daily range is the range of the dry bulb. The cooling dry bulb design temperature and range of
the dry bulb were found on the same table as the heating dry bulb design table. The cooling dry
bulb design temperature is 99oF at 0.4% and the range of dry bulb is 21.6
oF. Table 7-2 in the
HVAC textbook shows the percentage of daily range for each hour. The inside temperature of
the building during the summer is set at 74oF.
The sol air temperature, needed to calculate the conductive thermal loads of the outer shellcomponents is calculated by * where, Ta is the outside temperature, Et is the total solar radiation incident on the surface,
is
the surface color parameter, and is the long wave radiation term. The surface colorparameter is 0.15 for light colored surfaces and 0.30 for dark colored surfaces. The long wave
radiation term is -7oF for horizontal surfaces and 0
oF for vertical surfaces. To find the total solar
7/31/2019 HVAC FInal Report
9/42
The diffuse irradiance is calculated by
for vertical surfaces
for surfaces other then verticalwhere, C is the sky diffuse coefficient, Y is the ratio, and is the tilt angle. The sky diffusecoefficient used was 0.138, found on Table 7 of the 2005 ASHRAE handouts. The ratio is
calculated by for for where, is the solar angle.
The ground reflective irradiance was calculated by *where, g is the ground reflectance.
The total irradiance was then calculated by .Supply Air Temperature
The supply airflow rates required for the building are based on the supply air temperatures. The
supply air temperature used during the winter was 140oF with low humidity and during the
summer was 50oF at 85% relative humidity.
The enthalpies and humidity ratios for the supply air conditions were found as follows. The
equation to solve for enthalpy is
where, T is the temperature, hda is the enthalpy of dry air, is the humidity ratio, and hwv is theenthalpy of water vapor. The enthalpy of dry air was found by . Theenthalpy of water vapor was found by The humidity
7/31/2019 HVAC FInal Report
10/42
where, supply is the supply humidity ratio, int is the internal mass flow rate, and supply is thesupply mass flow rate. This equation will be used later in the report.
THERMAL ANALYSIS
Determination Of Heating and Cooling Loads
The first step in determining thermal loads on the building is to estimate the thermal resistancesof all shell components. This includes each exterior wall, ceiling, doors, and windows.
The total thermal resistance was calculated following the equation: where, Rout is the air resistance of moving air, Rcomponent is the thermal resistance of a
representative section of the component, and Rin is the air resistance of still air. The thermal
resistance was calculated for both winter and summer based on the different air resistance valuesfor moving air.
The thermal resistance of the wall is calculated based on a detailed representative section, asshown in Figure 8 below.
7/31/2019 HVAC FInal Report
11/42
where, Atotal is the total area of the wall, Astud is the total area of the studs, Rstud is the thermalresistance of the studs, Ainsualtion is the total area of the insulation, R insuluation is the thermal
resistance of the insulation, Aspacer is the total area of the spacers, and the Rspacer is the thermal
resistance of the spacers. An example calculation is shown in Appendix II.
The thermal resistance of the ceiling is found similarly to the walls. The representative section
of the ceiling being analyzed is shown below, Figure 9.
Figure 9. Representative Section of the ceiling.
The equation for the thermal resistance of the ceiling is as follows.
where, Rinsulation is the resistance of 12 loose insulation, Rtruss is the resistance of southerncypress softwood, and Rgypsum is the resistance of 5/8 gypsum wallboard.
7/31/2019 HVAC FInal Report
12/42
*
where, A is the area, T is the temperature difference between the outside and inside, and R is
the thermal resistance. The slab/foundation heat loss was calculated by * where, P is the perimeter, FP is the heat loss coefficient, and T is the temperature differencebetween the outside and inside. The total thermal loads acting on the walls, ceiling, windows,
doors, and foundation/slab of are shown on Table 2 below.
Table 2. Heat Gain for winterComponent Rwinter (ft
2*h*oF/Btu) A (ft2) Tin (oF) Tout (
oF) Heat Loss (Btu/h)
North Wall 14.5 1159.5 70 22 3842
East Wall 15.4 400 70 22 1247
West Wall 15.4 400 70 22 1247
South Wall 16.7 592.5 70 22 1700
Ceiling 35.8 4800 70 22 6434
Windows 1.5 572.25 70 22 17854
North Doors 2.7 40.5 70 22 719
South Doors 6.3 60.75 70 22 467
Perimeter (ft) FP (Btu/ft2*h*oF) Tin (
oF) Tout (oF) Heat Loss (Btu/h)
Slab/Foundation 320 0.49 70 22 7526
From the table above, the total thermal loads acting on each business was calculated by addingthe appropriate components. These values are shown on Table 3 below.
Table 3. Total Winter Thermal LoadsThermal Loads (Btu/h)
Health Club 14173
Coffee House 12692
Book Store 14173
7/31/2019 HVAC FInal Report
13/42
Table 4. Conductive Thermal Loads calculated in Btu/hTime North Wall East Wall South Wall West Wall North Roof South Roof
1 -131 -8 -16 -8 1243 3972 -562 -44 -61 -44 907 297
3 -949 -77 -110 -77 431 144
4 -1294 -104 -146 -104 33 11
5 -1560 -123 -170 -123 16 5
6 -1551 -101 -181 -101 112 33
7 -379 163 -149 163 625 143
8 635 516 -72 516 1905 484
9 977 765 64 765 3803 1132
10 1532 879 303 879 6000 2012
11 2522 886 601 886 8188 2980
12 3730 812 894 812 10221 3922
13 4930 697 1132 697 11945 4730
14 5951 709 1283 709 13195 5310
15 6675 878 1326 878 13872 5596
16 7023 1091 1258 1091 13923 5557
17 6983 1251 1087 1251 13330 5195
18 6740 1304 858 1304 12120 4542
19 6607 1201 657 1201 10351 3666
20 5719 886 483 886 8104 2687
21 3844 499 330 499 5740 1811
22 2245 249 210 249 3824 1187
23 1204 122 117 122 2546 793
24 453 45 43 45 1748 550
The RTS, representative solar values were found on table 7-31 (non-solar) and table 7-32 (solar)
of the HVAC textbook, based on the flooring and window percentage. The following steps were
conducted on each room rather then the entire wall. Similarly to the CTS the representative solarvalues were multiplied by the corresponding radiant heat gain calculated by
* where, Aunshaded is the area of the window not shaded, (SHGC)angle is the incidence angle value,
7/31/2019 HVAC FInal Report
14/42
The incidence angle and hemispherical diffuse values were found on table 7-4 in the HVAC
textbook for clear glass. The sum of radiant heat gain per hour was calculated and added to theconductive heat gain calculated by
* where, U is the thermal transmittance, A is the area of the window, and T is the temperature
difference. The thermal transmittance is found the equation
. The thermal load through
the window as then calculated by
.The calculated thermal loads through the window for each business is shown on Table 5 below.
Table 5. Thermal Loads through the Window calculated in Btu/hTime Health Club Coffee House Book Store
1 1117 1170 470
2 778 825 276
3 510 550 129
4 303 338 -5
5 164 195 -87
6 587 632 777
7 1300 1367 1883
8 2203 2296 3100
9 3228 3347 4403
10 4307 4452 5653
11 5615 5794 7192
12 7262 7491 9293
13 8158 8410 9859
14 8073 8312 8886
7/31/2019 HVAC FInal Report
15/42
Table 6. The Occupancy ChartHealth Club Coffee House Book Store
Workers Customers Workers Customers Workers CustomersTime # of People # of People # of People # of People # of People # of People
1 0 0 0 0 0 0
2 0 0 0 0 0 0
3 0 0 0 0 0 0
4 0 0 0 0 0 0
5 0 0 2 0 0 0
6 0 0 2 15 0 0
7 0 0 2 20 0 0
8 0 0 2 20 0 0
9 0 0 2 15 2 010 0 0 2 10 2 4
11 0 0 2 10 2 5
12 0 0 2 0 2 5
1 0 0 0 0 2 6
2 0 0 0 0 2 4
3 2 0 0 0 2 3
4 2 8 0 0 2 2
5 2 18 0 0 2 2
6 2 18 0 0 2 5
7 2 18 0 0 2 68 2 18 0 0 2 7
9 2 8 0 0 2 8
10 2 0 0 0 2 3
11 0 0 0 0 2 0
12 0 0 0 0 0 0
Table 7. The Equipment ChartHealth Club
Equipment ON/Off
Personal Computer (Btu/h) 187.55 When Workers are Present
Monitor (Btu/h) 187.55 When Workers are Present
Task Light (Btu/h) 57.97 When Workers are Present
Laser Printer (Btu/h) 1091 2 When Workers are Present
7/31/2019 HVAC FInal Report
16/42
From the occupancy table, the thermal loads were calculated based on the heat gains per person
by activity given on table 7-14 in HVAC textbook. The table gives values of total heat, sensible
heat, and latent heat in Btu/h/person and the percent sensible heat in radiant. The total heat,sensible heat, and latent heat were each multiplied to the number of people present in the room
for each hour. Then adding the sensible heat and latent heat you calculate the convective heatgain. The radiant heat gain was found by multiplying the percent sensible heat in radiant by the
sensible radiant for each hour. The equipment thermal loads were calculated in a similar manor
to the human thermal load. Most of the equipment power was found on tables 7-18 to 7-24 in the
HVAC textbook, the rest were looked up online. Table 7-26 in the textbook provides possibleequipment that can be split into radiant and convective parts. The sum of the radiant human and
equipment loads for each hour was solved before using the RTS method to find the total radiantheat gain per hour. The total heat gain of internal loads for each business are found by
.The calculated total internal loads calculated for each business is shown on table 8 below.
Table 8. Internal thermal loads calculated in Btu/h.
Time Health Club Coffee House Book Store1 2541 915 712
2 2396 265 525
3 2296 -255 423
4 2202 814 345
5 2104 12193 302
6 2033 15024 262
7 1984 16940 239
8 1936 17683 216
9 1912 18812 996310 1910 21756 11438
11 1887 15511 11958
12 1839 16384 12100
7/31/2019 HVAC FInal Report
17/42
Table 9. Total Summer Thermal Loads
Time Health Club (Btu/h) Coffee House (Btu/h) Book Store (Btu/h) Total Thermal Loads (Btu/h)1 3838 1609 1362 6809
2 2985 915 612 4511
3 2224 265 -30 2458
4 1600 -255 -565 781
5 1189 814 -864 1139
6 1557 16763 -24 18295
7 3064 19594 1902 24560
8 5078 21510 4255 30843
9 7220 22253 16445 45918
10 9725 23382 20598 5370611 12644 26326 24293 63264
12 15826 15511 28119 59456
13 17999 16384 30383 64767
14 18912 17222 29920 66053
15 19930 17499 29713 67143
16 60358 16969 28700 106027
17 65639 13789 25258 104686
18 66331 13697 25746 105775
19 64528 11485 23410 99423
20 62179 9065 20897 9214121 51825 6693 18665 77184
22 9781 4777 15304 29861
23 6256 3391 13089 22735
24 4863 2382 2364 9608
DETERMINIATION OF BUILDING AIRFLOWS
The building airflows are shown on Figure 11, below. The outside air and recirculated air entersthe air-handling unit (AHU). The supply air exits the air-handling unit then disperses into each
business. The return air divides into recirculated air and exhaust air.
7/31/2019 HVAC FInal Report
18/42
*
where, Pb is the absolute outside pressure, h is the vertical distance from the neutral pressurelevel, To is the outside absolute temperature, and Ti is the inside absolute temperature. The
absolute outside pressure used was 14.696 psi for 1 atmosphere. The vertical distance from the
neutral pressure level was found by dividing the building height into two feet increments, asshown on Figure 12, below. The neutral pressure level was at the height of 5 feet.
Figure 12. The vertical distance from the neutral pressure level
The absolute temperatures used are shown on Table 10 below.
7/31/2019 HVAC FInal Report
19/42
was 11.06 m/s. The average wall pressure coefficient was found on chapter 16, Figure 6, of the
2005 ASHRAE fundamentals handout. The pressure coefficient is located based off of the wind
angle, which can be found on the wind data chart. The average wall pressure coefficients usedare shown on Table 11 below.
Table 11. Average Wall Pressure Coefficient for each wallSummer Winter
Cp (west) 0.1 Cp (east) 0.5
Cp (north) 0.4 Cp (south) -0.4
Cp (east) -0.6 Cp (west) -0.1
Cp (south) -0.5 Cp (north) -0.6
The wind pressure is calculated in so a unit conversion is need to convert to inches ofH2O. The wind pressures calculated are shown on Table 12 below.
Table 12. The calculated Wind PressureSummer Wind Pressure (in of H2O) Winter Wind Pressure (in of H2O)
West 0.017 East 0.162
North 0.067 South -0.130
East -0.100 West -0.032
South -0.084 North -0.194Ceiling -0.084 Ceiling -0.162
The building pressurization is approximately 0.001 inches of H2O because of the HVAC systemused. The stack pressure, wind pressure, and building pressurization were added together for
each wall component and the wind pressure and building pressurization were added together for
the ceiling total. A sample calculation to find the total pressure difference can be found onAppendix II, Sample Calculation 2. Table 13 below, shows the total pressure difference for each
component.
Table 13. The total pressure differenceSummer (inches of H20) Winter (inches of H20)
North 0 063 -0 176
7/31/2019 HVAC FInal Report
20/42
The calculated infiltration flow rates for each business and the building are shown on Table 15
below.
Table 15. Infiltration Flow RatesSummer (cfm) Winter (cfm)
Heath Club 336 198
Coffee House 312 182
Book Store 376 270
Building 1024 649
The next step in determining the building airflows is to calculate the required outside air tomaintain the indoor air quality in a building. The ASHRAE standard 62.1-2004 minimum
ventilation rates are found on Table 5-9 of the HVAC textbook for different occupancy facilities.The minimum outdoor air ventilation rate was found by where, the people outdoor air rate and area outdoor air rate are found on Table 5-9. The area of
each business is 1600 ft2
and the maximum amount of people is 20 for the health club, 22 for thecoffee house, and 10 for the bookstore. The people outdoor air rate and area outdoor air rate
were found for health club/weight room, bars/cocktail lounges, and sales. Table 16 below shows
the calculated outdoor air rate for each business.
Table 16. The ASHRAE 62.1 required calculated outdoor air.Required Outdoor Air (cfm)
Health Club 496
Coffee House 453
Book Store 267
The building also came with a required outdoor air rate for each business. The required outdoor
air rate for the Health Club was 50 cfm/person, for the Coffee House 25 cfm/person, and for the
Book Store 10 cfm/person. The total building outdoor air for each business is located on Table17 below.
Table 17 The building required outdoor air
7/31/2019 HVAC FInal Report
21/42
where wv is the mass water vapor. The mass water vapor during the summer was solved usingthe equation
where, QL is the latent heat gain and hfg is the latent heat of vaporization. The latent heat gainswere found on Table 7-14 for people and Table 7-18 for equipment. Both tables were located in
the HVAC textbook. The latent heat of vaporization was found on Table 2-1 in the HVACtextbook under evaporative specific enthalpy at a certain temperature. The average human
temperature used was 98oF and the equipment was estimated to be 200
oF for the coffee maker
and espresso machine and 100oF for the dishwasher. The latent heat of vaporization used was
1059.32 Btu/lb for humans and 1048.03 Btu/lb for equipment.
The winter mass water vapor was calculated following the where, Q is the winter thermal flow rate and hfg is the evaporative specific enthalpy. Theevaporative specific enthalpy was found on Table 2-1 in the HVAC textbook at the buildings
winter room temperature. The value found was 1053.68 Btu/lb.
The internal enthalpy during the summer was calculated by the equation . The latent heat of vaporization for workers and customers are thesame value. During the winter the internal enthalpy is equal to the evaporative specific enthalpy
at room temperature.
By rearranging the energy balance equation, the supply mass flow rate is found by the equationbelow. ()
7/31/2019 HVAC FInal Report
22/42
The controlling ratio calculated for each business is shown on Table 19 below.
Table 19. Controlling RatioControlling Ratio
Health Club 0.25
Coffee House 0.41
Book Store 0.22
Building 0.28
The supply airflows were adjusted for each business, to set the controlling ratio equal for each
room. The controlling ratio was set to 0.22, the lowest controlling ratio calculated. In order toprevent over ventilation the outside airflow must remain the same, so the supply airflow was
adjusted.
The exhaust airflow, recirculated airflow, and return airflow were the last values calculated. Theexhaust airflow rate was calculated by
where, the local exhaust airflow is 150 cfm from the three restroom exhaust fans. Therecirculated airflow was from the following equation. The return air was calculated by the equation below. The building airflows are shown on Table 20 below.
Table 20. The Building AirflowsSupply Airflow (cfm) Outside Air Requirement (cfm) Exhaust Airflow (cfm) Recirculated Air (cfm) Return Airflow (cfm)Health Club 4545 1000 850 3545 4395
Coffee House 2500 550 400 1950 2350
Book Store 1214 267 117 947 1064
7/31/2019 HVAC FInal Report
23/42
Determination Of Duct System
The next step in the thermal analysis was to determine the air duct routing and fittings. The topand side view of the supply and return air ducts are show on figures 13, 14, 15, and 16,
respectively. It should be noted the following figures are not to scale.
Figure 13. Top View of the Supply Air Duct Routing
7/31/2019 HVAC FInal Report
24/42
Figure 16. Side View of the Return Air Duct Routing
The air ducts are color-coded based on the dimensions, shown on Table 22 below.
Table 22. Duct SizeSupply Duct
Height (in) 12
Width (in) 44
Height (in) 10
Width (in) 37
Height (in) 8
Width (in) 22
Height (in) 9
Width (in) 33
Height (in) 7Width (in) 18
Height (in) 6
Width (in) 18
Height (in) 5
7/31/2019 HVAC FInal Report
25/42
is a rectangular duct so Table 9-1, in the HVAC textbook, was used to find the equivalent
rectangular duct dimensions. The fittings used in the duct are shown on Table 23, below. The
fitting information was found on Table 9-4, in the HVAC textbook, and on Chapter 21 of the2009 AHSRAE Fundamentals Handbook.
Table 23. Fitting TypeFitting Name
3-1 Elbow, Smooth Radius, Without Vanes
5-35 Cross, 90 degrees, Recatgular, Diverging
4-2 Transition, Rectangular, two sides parallel, symmetrical
SR5-15 Bullhead Tee Without Vanes, Diverging
5-28 Tee, Diverging, Rectangular Main and Tap
6-2 Damper, Butterfly, Rectangular
Next, the pressure drops in the ducts were calculated. The equation used was ( ) where, is the air density at 70
oF, g is gravity, h is the duct height in the building, V is the air
velocity traveling through the duct, and L1-2 is the frictional losses. The velocity and friction losswas found on Figure 9-2 in the HVAC textbook based on the flow rate and the previously
selected duct diameter. The frictional losses in straight pipes were found by the following
equation. The frictional losses in the fittings were found by where, c is the fitting loss coefficient and V is the air velocity at the entrance of the fitting. The
fitting loss coefficient were found on Table 9-4, in the HVAC textbook, and on Chapter 21 of the2009 ASHRAE Fundamentals Handbook for the specific fitting used. The needed values are
shown on Table 24.
7/31/2019 HVAC FInal Report
26/42
The supply duct pressure drops calculated from the air-handling unit to each vent without the
balancing dampers are shown on Table 25, below.
Table 25. Supply Duct Pressure DropHealth Club
AHU -> 1 (in H2O) 1.261
AHU -> 2 (in H2O) 1.261
AHU -> 3 (in H2O) 1.722
AHU -> 4 (in H2O) 1.722
Coffee House
AHU -> 5 (in H2O) 0.525
AHU -> 6 (in H2O) 0.525
AHU -> 7 (in H2O) 0.620AHU -> 8 (in H2O) 0.620
Book Store
AHU -> 9 (in H2O) 1.415
AHU -> 10 (in H2O) 1.415
AHU -> 11 (in H2O) 2.110
AHU -> 12 (in H2O) 2.110
The balancing dampers were added at each air vent in order to control the amount of airflow into
each room. Adding the frictional losses from the fully open damper to the largest calculated our
wanted pressure drop. The fitting loss coefficient for the other dampers were calculated by
*where, Pneeded is the wanted pressure drop, Pcalculated is the pressure drop calculated, and V is
the air velocity through the air vents. The fitting loss coefficients calculated are shown on Table
26, below.Table 26. Supply Duct Fitting Loss Coefficient
Health Club
AHU > 1 0 982
7/31/2019 HVAC FInal Report
27/42
Table 27. Supply Duct Damper AnglesHealth Club
AHU -> 1 17.50
AHU -> 2 17.50AHU -> 3 11.40
AHU -> 4 11.40
Coffee House
AHU -> 5 27.90
AHU -> 6 27.90
AHU -> 7 27.09
AHU -> 8 27.09
Book Store
AHU -> 9 17.64
AHU -> 10 17.64
AHU -> 11 0.000
AHU -> 12 0.000
The return duct pressure drops were calculated from the return fan to each air vent, from thereturn fan to the exhaust fan, and from the return fan to the air-handling unit. The calculated
pressure drops without balancing dampers are shown on Table 28, below.
Table 28. Return Duct Pressure Drops
HC -> Return Fan (in H2O) 0.3868
CH -> Return Fan (in H2O) 0.9635
BS -> Return Fan (in H2O) 0.5068
Return Fan -> Exhaust Fan (in H2O) 0.1869
Return Fan -> AHU (in H2O) 0.6965
Following the previous steps a damper was placed next to the air vent in each store. The fitting
loss coefficient and angles calculated are shown on Tables 29 and 30 respectively.
Table 29. Return Duct Fitting Loss CoefficientHC -> Return Fan 0.2704
CH -> Return Fan 0.0800
7/31/2019 HVAC FInal Report
28/42
*
*
* * *where, Q is the flow rate, D is the diameter, N is the speed in RPM, P is the pressure drop, and
is the air density. The diameter and air density do not change. A new lower speed was
originally guessed in order to calculate the new pressure and flow rate. The flow rate at thecalculated pressure of 0.9876 inches of H2O was found by interpolating. Once the equations
were set up in excel the new speed was varied until the desired flow rate and pressure drop were
found. The fan needs to run at a speed of 977.2 RPM in order to produce 7809 cfm at a pressuredrop of 0.9876 inches of H2O. The fan characteristics are shown on Figure 17, below.
Figure 17. Return Fan Characteristics
The exhaust fan had a calculated flow rate of 1367 cfm and a pressure drop of 0.2158 inches of
H O F h b i 13 125 i h if l i li bl h Th
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1.400
1.600
1.800
2.000
5800 6800 7800 8800 9800
PressureDro
p(inofH2O)
Flowrate (CFM)
Speed = 1034 RPM
Speed = 977.2 RPM
7/31/2019 HVAC FInal Report
29/42
The air-handling unit was not chosen. This is because a custom air-handling unit will be built to
meet the requirements needed to supply the appropriate amount of air to the building. The air-handling unit needs to produce a flow rate of 8259 cfm at a pressure drop of 2.1138 inches of
H2O.
DETERMINATION OF SYSTEM LOADS
The next step in the thermal analysis was to determine the air-handling unit system loads. A
detailed diagram of the air-handling unit is shown below, Figure 19.
Figure 19. Detailed Air-Handling Unit Diagram
In order to calculate the system loads in the air-handling unit the mass flow rates, humidity ratio,
and enthalpies were calculated. The mass flow rate was found by the following equation. The densities used were 0.072 lbm/ft3 for the outside air at 90oF and 0.074 lbm/ft3 for
recirculated air at 74oF. The supply mass flow rate is equal to the outside air and recirculated air
added together. The mass flow rates calculated are shown on Table 31, below.
Table 31. Mass Flow Rates in lbm/hrSummer Winter
Outside Air 7859 279
R i l t d Ai 28755 900
7/31/2019 HVAC FInal Report
30/42
where,
is the power input to the fan, and hcondensate is the saturated liquid enthalpy at 50
oF and
140o
F found in Table 2-1 in the HVAC textbook. The power was found for the return fan byP=VI. On the specification sheet provided for the 7H483 square centrifugal in-line blower the
voltage and current can be found. The voltage and current used was 208 V and 9.2 ampsrespectively. The power used is 6525 Btu/hr. During the summer the enthalpies calculated were
31.5 Btu/lbm for outside air, 25.5 Btu/lbm for recirculated air, 19.0 Btu/lbm for supply air, and
18.1 Btu/lbm for condensation. The system-cooling load calculated was 23 tons (276777 Btu/hr).
The system-heating load could be calculated following the steps above, but to be conservative
the winter thermal loads calculated above was used. The system-heating load was 41041 Btu/hr(3.4 tons).
COMPARISON TO eQUEST COMPUTER MODELING
Finally a thermal energy simulation was performed on the building. The program used for thesimulation was eQUEST. The building information given through out this report was used to set
up the simulation. Once the simulation was completed the LS-D: Building Month Loads
Summary and the SS-D: Building HVAC Load Summary were viewed. The reports are locatedin Appendix III. The LS-D report only provides static loads with no ventilation and the SS-D
report includes ventilation on the thermal loads.
The maximum heating load provided on the LS-D report is 8,283 Btu/hr. This was compared to
the system-heating load calculated, which was 41,041 Btu/hr. The value provided was
significantly lower then the calculated heating load. The main reason this was found could be
due to input error in the simulation program. However, the maximum cooling load, located onthe SS-D report, was 236,754 Btu/hr. This value is closer to our calculated heating load, which
was 276,777 Btu/hr.
7/31/2019 HVAC FInal Report
31/42
The total thermal loads acting on each business as well as the building during the summer is
shown on Figure 20 below.
Figure 20. The Total Summer Thermal Loads based on a 24-hour profile.
From the chart, the Health Club produces the highest heat gain. This makes sense due to theamount of equipment used during business hours. The Coffee Houses maximum heat gain isaround 11:00 AM due to the business hours. This makes since because the conductive heat gain
through the walls peak around mid-day and the business is open till 11:00 AM. The Book
Stores heat gain curve is gradual. This makes sense because the Book Store is open from 10:00
AM10:00 PM with a steady amount of internal thermal loads.
The infiltration and building airflow rates were calculated for the building and each business.The infiltration airflow rates were calculated for both summer and winter and are shown on
Table 33, below.
-10000
10000
30000
50000
70000
90000
110000
0 5 10 15 20 25
Heat
Gain(Btu/h)
LST
Heath Club
Coffee House
Book Store
Building Total
7/31/2019 HVAC FInal Report
32/42
infiltration airflow rates were compared to the supply airflow rates and found to be negligible.
This means infiltration does not need to be accounted for in our building airflow rates.
The building ductwork and fan selections were selected. The supply pressure drop from the air-
handling unit to each air vent was set at 2.1138 inches of water, with dampers place next to eachvent, at a flow rate of 8,259 cfm. The angle each damper needs to be set at is shown on Table 35,
below.
Table 35. Supply Duct Damper AnglesHealth Club
AHU -> 1 17.50
AHU -> 2 17.50AHU -> 3 11.40
AHU -> 4 11.40
Coffee House
AHU -> 5 27.90
AHU -> 6 27.90
AHU -> 7 27.09
AHU -> 8 27.09
Book Store
AHU -> 9 17.64
AHU -> 10 17.64AHU -> 11 0.000
AHU -> 12 0.000
The return pressure drop from the return fan to each air vent was set at 0.9876 inches of water,with the dampers placed next to each vent, at a flow rate of 7,809 cfm. The angle each damper
needs to be set at is shown on Table 36, below.
Table 36. Return Duct Damper Angles
HC -> Return Fan 7.62CH -> Return Fan 0.00
BS -> Return Fan 9.46
Th f d i 24 i h if l i li bl i d f 977 2
7/31/2019 HVAC FInal Report
33/42
loads are lower then the calculated loads. This error could be due to human input error, when
modeling the building.
REFERENCES
2005 ASHRAE Handbook- Fundamentals Handouts
2009 ASHRAE HandbookFundamentals (SI Edition)
Crowe, Clayton, Donald Elger, Barbara Williams, and John Roberson.Engineering Fluid
Mechanics. 9th. Wiley, 2009. 92-97. Print.
Howell, Ronald H., Harry J. Sauer, and William J. Coad. Principles of Heating, Ventilating, and
Air Conditioning. Atlanta, GA: American Society of Heating, Refrigerating and Air-
Conditioning Engineers, 2005. Print.
7/31/2019 HVAC FInal Report
34/42
Appendix I
7/31/2019 HVAC FInal Report
35/42
Table 1. Values Needed for Calculations
Sol Air Temperature Calculations
0.15 Dark Surface 0 Vertical SurfaceA (Btu/h*ft
2) 346 Table 7 in Chapter 31 of 2005 ASHRAE Fundamentals
B 0.186 Table 7 in Chapter 31 of 2005 ASHRAE Fundamentals
C 0.138 Table 7 in Chapter 31 of 2005 ASHRAE Fundamentals
(degree) 20.6 Table 7 in Chapter 31 of 2005 ASHRAE Fundamentals
ET (min) -6.2 Table 7 in Chapter 31 of 2005 ASHRAE FundamentalsCN 0.99
g 0.2 Table 10 in Chapter 31 of 2005 ASHRAE
Fundamentals
Enthalpy Calculations
air(140oF) (slug/ft
3) 0.00206 Table A.3 in Fluid Mechanics Textbook
air(50oF) (slug/ft
3) 0.00242 Table A.3 in Fluid Mechanics Textbook
Psat(140
o
F) (psi) 2.8926 Table 2-1 in HVAC TextbookPsat(50oF) (psi) 0.17811 Table 2-1 in HVAC Textbook
hfg(74oF) (psi) 1053.68 Table 2-1 in HVAC Textbook
hfg(98oF) (psi) 1037.81 Table 2-1 in HVAC Textbook
hfg(80oF) (psi) 1048.03 Table 2-1 in HVAC Textbook
Thermal Resistance Calculations
Rplywood 0.62 Table 5-15 in HVAC textbook
Rgypsum 0.56 Table 5-15 in HVAC textbook
Rstud = Rspacer = Rtruss 1.1 Table 5-15 in HVAC textbookRwall insulation 21 Table 5-15 in HVAC textbook
Rout, winter 0.17 Table 5-12 in HVAC textbook
7/31/2019 HVAC FInal Report
36/42
Appendix II
7/31/2019 HVAC FInal Report
37/42
Sample Calculation 1
Find: thermal resistance for the east wall
Given: Rplywood = 0.62 (ft2*h*oF/Btu)
Rgypsum = 0.56 (ft2*h*oF/Btu)
Rstud/spacer = 1.1 (ft2*h*
oF/Btu)
Rwallinsulation = 21 (ft2*h*
oF/Btu)
Rout,summer = 0.25 (ft2*h*oF/Btu)
Rout,winter = 0.17 (ft2
*h*o
F/Btu)Rin = 0.68 (ft
2*h*
oF/Btu)
Atotal= (40+1.5)X(16+1.5) = 726.25 in2 = 5.04 ft2
Astud= 1.5X41.5 = 62.25 in2 = 0.432 ft2
Aspacer= 1.5X14.5 = 21.75 in2
= 0.151 ft2
Ainsulation= 14.5X38.5 = 588.25 in2
= 3.877 ft2
Finding Rparallel:
Finding Rwall:
7/31/2019 HVAC FInal Report
38/42
Sample Calculation 2
Find: Total Pressure Difference
Given: Pb = 14.696 psiTo = 549.67
oR
Ti = 533.67oR
h1 = 4
= 0.00224 slug/ft3
V = 8.49 m/s
Cp = 0.1Pp = 0.001 in of H2
O
Finding Ps: * *
Finding Pw: *
Finding P:
7/31/2019 HVAC FInal Report
39/42
SAMPLE CALCULATION 3
Find: Supply Airflow Rate
Given: Tsupply = 50oF supply = 85 %
= 0.00242 slug/ft3
Psat = 0.17811 psi
P (1atm) = 14.696 psi
Troom = 74oF
Q = 66331 Btu/hr
Finding hsupply:
* * Finding hroom values:
Finding : ()
7/31/2019 HVAC FInal Report
40/42
Appendix III
7/31/2019 HVAC FInal Report
41/42
41
HVAC Project DOE-2.2-47h2 5/01/2012 13:44:18 BDL RUN 3
REPORT- LS-D Building Monthly Loads Summary WEATHER FILE- Portland OR TMY2
---------------------------------------------------------------------------------------------------------------------------------
- - - - - - - - C O O L I N G - - - - - - - - - - - - - - - - H E A T I N G - - - - - - - - - - - E L E C - - -
MAXIMUM MAXIMUM ELEC- MAXIMUM
COOLING TIME DRY- WET- COOLING HEATING TIME DRY- WET- HEATING TRICAL ELEC
ENERGY OF MAX BULB BULB LOAD ENERGY OF MAX BULB BULB LOAD ENERGY LOAD
MONTH (MBTU) DY HR TEMP TEMP (KBTU/HR) (MBTU) DY HR TEMP TEMP (KBTU/HR) (KWH) (KW)
JAN 19.12405 6 14 47.F 42.F 42.865 -0.635 27 6 20.F 17.F -8.283 729. 1.349
FEB 17.53141 20 16 58.F 51.F 44.040 -0.525 15 6 28.F 28.F -6.294 658. 1.349
MAR 20.14322 18 16 70.F 52.F 46.821 -0.478 11 6 32.F 32.F -5.464 729. 1.349
APR 20.09656 20 15 77.F 60.F 47.724 -0.341 30 5 34.F 34.F -4.278 705. 1.349
MAY 22.45200 20 16 87.F 61.F 50.274 -0.140 2 5 44.F 42.F -2.136 729. 1.349
JUN 23.16181 25 15 90.F 67.F 51.861 -0.023 3 5 49.F 46.F -0.788 705. 1.349
JUL 25.21755 23 16 90.F 69.F 52.437 0.000 13 4 52.F 50.F -0.037 729. 1.349
AUG 25.90529 14 16 92.F 63.F 53.684 0.000 0 0 0.F 0.F 0.000 729. 1.349
SEP 24.29659 9 16 92.F 67.F 53.867 -0.002 22 5 45.F 45.F -0.545 705. 1.349
OCT 23.12724 6 15 77.F 59.F 51.237 -0.065 20 5 34.F 34.F -1.996 729. 1.349
NOV 20.72382 1 14 64.F 55.F 47.909 -0.154 30 6 31.F 31.F -3.236 705. 1.349
DEC 19.92703 2 21 55.F 52.F 43.385 -0.376 26 6 32.F 30.F -4.229 729. 1.349--------- ---------- --------- ---------- -------- -------
TOTAL 261.707 -2.739 8581.
MAX 53.867 -8.283 1.349
7/31/2019 HVAC FInal Report
42/42
42
HVAC Project DOE-2.2-47h2 5/01/2012 13:44:18 BDL RUN 3
REPORT- SS-D Building HVAC Load Summary WEATHER FILE- Portland OR TMY2
---------------------------------------------------------------------------------------------------------------------------------
- - - - - - - - C O O L I N G - - - - - - - - - - - - - - - - H E A T I N G - - - - - - - - - - - E L E C - - -
MAXIMUM MAXIMUM ELEC- MAXIMUM
COOLING TIME DRY- WET- COOLING HEATING TIME DRY- WET- HEATING TRICAL ELEC
ENERGY OF MAX BULB BULB LOAD ENERGY OF MAX BULB BULB LOAD ENERGY LOAD
MONTH (MBTU) DY HR TEMP TEMP (KBTU/HR) (MBTU) DY HR TEMP TEMP (KBTU/HR) (KWH) (KW)
JAN 0.55643 18 15 56.F 51.F 39.127 -116.269 26 23 20.F 17.F -390.024 2597. 8.003
FEB 1.17070 21 16 60.F 48.F 63.625 -88.218 1 6 29.F 29.F -324.268 2403. 9.368
MAR 6.06866 19 16 70.F 55.F 104.511 -84.430 12 6 32.F 31.F -302.880 3008. 11.050
APR 11.11841 21 14 73.F 64.F 192.307 -73.140 30 6 34.F 34.F -283.999 3254. 16.521
MAY 31.70915 21 14 76.F 63.F 180.895 -61.494 25 6 43.F 41.F -222.872 4653. 16.334
JUN 54.54934 25 17 92.F 67.F 222.171 -52.241 29 6 49.F 47.F -185.684 5998. 21.484
JUL 72.95649 23 17 90.F 69.F 236.754 -48.001 14 6 54.F 51.F -163.785 7170. 22.005
AUG 78.33167 3 19 83.F 68.F 221.836 -42.261 21 6 51.F 49.F -170.710 7584. 21.414
SEP 62.64047 9 16 91.F 68.F 227.226 -50.172 22 6 45.F 45.F -208.670 6439. 21.588
OCT 25.25869 12 17 71.F 62.F 172.900 -69.073 23 6 34.F 34.F -279.807 4242. 15.133
NOV 3.78992 1 14 63.F 56.F 113.238 -79.726 30 6 31.F 31.F -305.775 2762. 11.482
DEC 3.23061 13 15 61.F 58.F 123.523 -102.420 31 23 30.F 25.F -319.470 2797. 12.017--------- ---------- --------- ---------- -------- -------
TOTAL 351.380 -867.443 52906.
MAX 236.754 -390.024 22.005
MAXIMUM DAILY INTEGRATED COOLING LOAD (DES DAY ) 0.000 (KBTU)
MAXIMUM DAILY INTEGRATED COOLING LOAD (WTH FILE) 0.000 (KBTU)