ac report

Mississippi State University

Carpenter Hall 479-1 Hardy Rd.

MS State, MS 39762

ME 3473/6373 – Air Conditioning

Air Conditioning System Calculations Report for a Small Office Building

Team ACIRI

Henrique Coura, Marco Harrington, Tadeu Fagundes, William Quigley, Zachary Myers

Air Conditioning Installation & Repair INC.

Table of Contents

1 – Introduction 3

2 - Cooling Load Summary 5

3 - Piping Summary 6

4 - Coil Sizing Summary 7

5 - Cooling Unit Suggestion 8

6 - Cost Calculations 11

7 – References 12

8 - Appendix

Appendix A 13

Appendix B 14

Appendix C 17

Appendix D 20

Appendix E 22

Page 1


Abstract

After being approached by Dr. Mago with a project, ACIRI began designing a cooling

system for a small office. The dimensions of the building, the materials used for construction,

office equipment, and time of day were all things that had to be taken into consideration. With

this in mind the cooling load was calculated for the times of 1pm-5pm for each of the rooms and

it was found that the 5pm time was critical for the loads. Next the coil sizing was calculated and

it was discovered that the total coil capacity was 10.3 ton. With this data it was noted that two

Rheem RLKL 6 Ton units would fit the needs for the small office. Next, the schematics and

calculations of the piping system for the office were done. Finally all the data was analyzed and

the most efficient cost was provided. For reliability two units are preferred. The estimated cost,

for the whole system, with two cooling units, is of US$9330.08.

Figure 1. Rheem RKLK 6-Ton unit Figure 2. Piping System Schematic

Page 2


1 – Introduction

Dr. Mago came to ACIRI seeking a cooling solution for a small office. The office was to be

located in Starkville, MS (33ᴼ 27’ N latitude). The outdoor design conditions for the location are: 96ᴼF

dry-bulb temperature, 76.6ᴼF wet-bulb temperature, with a 19.3ᴼF daily. Indoor design conditions are

75ᴼF dry bulb and 50% RH. Dr. Mago also provided information on the building materials and the floor

plan. With this information ACIRI began assessing what was needed for a cooling system.

Figure 3. Building Information

Page 3


Figure 4. Floor Plan

Page 4


2 - Cooling Load Summary

To determine the quantity of air that needs to be provided to the each room, the cooling load of

each was calculated for the time periods of 1-5pm. Taking known data, data based on the location, and

data on material used it was calculated that the maximum air quantity needed for each time frame was 8.4

tons. Naturally, each room requires its own share of this total and the ratio is shown on the chart below.

This chart is similar for each time frame but has slight variations in the ratios. More details and in depth

calculations of the cooling load can be found in Appendix A.

Office 1Office 2Office 3Office 4Office 5Office 6Office 7VestibuleLobbyWork AreaJanitorBath 1Bath 2Break RoomConf. RoomHallway

Figure 5. Air quantity ratio per room

Page 5


3 - Coil Sizing Summary

On the next step, the sizes and amount of air to be provided by the coils were calculated. For the

given inside and outside conditions, it was found that the air quantity needed is 4474 cfm and the coil size

to be about 10.3 tons. We selected two Rheem RKLK units. Each of those units can provide up to

2400 cfm of air flow and 6 tons of cooling capacity (See more details on the next page). Detailed coil

sizing calculations can be found in Appendix B.

Page 6


4 - Cooling Unit Suggestion

Taking the schematics and calculations into consideration, the ideal setup for the small office

would be two Rheem RKLK 6-Ton Units. These units provide 6 tons of air each. The max needed

is 10.4 tons, thus allowing the system to work properly on a unusual hot day. Two units are

preferred for reliability and continuous comfort in the event that one unit goes down. The unit is

efficient and user friendly. It also comes with an array of options and accessories that make it

even more suitable for personal customization. The pricing for this unit can be found in the Cost

Calculations section.

Figure 6. Rheem RKLK 6-Ton Unit

Page 7


5 - Piping Calculations Summary

After the cooling load was calculated, the pipe sizing was calculated and schematics of the system

were drawn. All calculations are detailed and technical and can be found in Appendix C (system 1) and

Appendix D (system 2). The schematics below describe where the pipes will be placed, what units they

go with, and the size of the pipes.

Figure 7. Unit locations

Page 8

Unit 1

Unit22


Figure 8. 3D Schematic of the piping system

Figure 9. Unit 1 Pipe Schematics

Page 9


Figure 10. Unit 2 Pipe Schematics

Page 10


6 - Cost Calculations

After having decided and calculated all the cooling units needed, pipe lengths and special

junctions for them, it was estimated the price for the whole project to be made. The project will cost

US$9330.08. This price was considered to be fair by our group, being reasonable for such type of office.

Most of the cost is at the units, which costs a little less than four thousand. This was expected, since it is

the most of the equipment part and the most important one.

Page 11


7 – References

1.http://www.commercial.carrier.com/commercial/hvac/product_description/

1,3059,CLI1_DIV12_ETI434_PRD1717,00.html

2.https://www.rheemote.net/docstore/webdocs/Public/ServicePublic/Trouble2a/pdfs/SC_Package/

RLKL/92-23577-100-01_RLKL.pdf

3. http://www.rheem.com/product/commercial-package-ac-rlkl-6-ton

4. Handouts and notes from ME 4373/6373 – Air Conditioning, by Dr. Pedro Mago, Professor from

Mississippi State University, United States

Page 12


8 – Appendix:

Appendix A

CONSTANTSUwall Upartition Uroof Uwindow Udoor Toutside Tdesign Ceiling Height CLF lights CLF people Lights density W/ft^20.25141797 0.07 0.08967012 0.55 0.32 96 75 9 0.89 0.83 2

Figure 11. Constant used for calculations

Width Area CLTDcorr qOffi ce 6 15.2 136.8 22 756.66752Offi ce 7 12.2 109.8 22 607.32525Break Room 20.6 185.4 22 1025.4836

Width Area CLTDcorr qOffi ce 2 17 153 39 1500.211Offi ce 3 12.1 108.9 39 1067.7973Offi ce 4 10 90 39 882.47707Offi ce 5 10 90 39 882.47707Offi ce 6 10.9 98.1 39 961.90001

Width Area CLTDcorr qOffi ce 2 10.8 97.2 26 635.38349Offi ce 1 16.2 145.8 26 953.07524Vestibule 6.2 55.8 26 364.75719Lobby 14.8 133.2 26 870.71071

Width Area CLTDcorr qLobby 13.4 120.6 26 788.34619Work Area 11.4 102.6 26 670.68258Janitor 7.3 65.7 26 429.47218Bath 1 7.3 65.7 26 429.47218Bath 2 7.3 65.7 26 429.47218Break Room 13.3 119.7 26 782.46301

Windows Dir. Dimensions CLTDcorr qcond qrad qtotalN 4 4 26 228.8 480.2356 709.0356W 4 4 26 228.8 745.6289 974.4289S 8 1 26 114.4 417.9867 532.3867E 4 4 26 228.8 796.18 1024.98

North Facing Walls

East Facing Walls

South Facing Walls

West Facing Walls

Figure 12. Wall Calculations

Page 13


Door Dir. CLTDcorr qAny 3 7 26 174.72

Area CLTDcorr qroof IHGlights qlightsOffi ce 1 147.42 41 541.985933 1207.1929 1074.402Offi ce 2 183.6 41 675.000795 1503.4637 1338.083Offi ce 3 130.68 41 480.441743 1070.1124 952.4Offi ce 4 108 41 397.059291 884.3904 787.1075Offi ce 5 108 41 397.059291 884.3904 787.1075Offi ce 6 165.68 41 609.118365 1356.7204 1207.481Offi ce 7 132.98 41 488.897635 1088.9466 969.1625Vestibule 56.482 41 207.654656 462.5198 411.6426Lobby 164.429 41 604.519095 1346.4762 1198.364Work Area 110.58 41 406.544597 905.5175 805.9106Janitor 70.81 41 260.331189 579.84893 516.0655Bath 1 70.81 41 260.331189 579.84893 516.0655Bath 2 70.81 41 260.331189 579.84893 516.0655Break Room 247.82 41 911.104015 2029.3484 1806.12Conf. Room 534.36 41 1964.56114 4375.7672 3894.433Hallway 577.539 41 2123.30765 4729.3514 4209.123

People IHGsens IHGlat qsen qlat250 200 207.5 200Any room with

people doing offi ce work

Dimensions

Roof & Lights

Figure 13. Door, Lights, Roof and People calculations

EquipmentSensible Latent

Printer 1000Computer 1100Cofee Maker 3580 1540Copy Machine 1200

Rate of Heat Gain

Figure 14. Equipment Calculation

Page 14


Area Volume Flowrate 1pm 2pm 3pm 4pm 5pm qlatentOffi ce 1 147.42 1326.78 11.0565 229.58491 248.3633 255.4052 253.0578551 231.9322 331.920553Offi ce 2 183.6 1652.4 13.77 285.92992 309.3169 318.087 315.163629 288.8533 413.380908Offi ce 3 130.68 1176.12 9.801 203.51482 220.1608 226.4031 224.3223477 205.5956 294.22994Offi ce 4 108 972 8.1 168.19407 181.9511 187.11 185.39037 169.9137 243.16524Offi ce 5 108 972 8.1 168.19407 181.9511 187.11 185.39037 169.9137 243.16524Offi ce 6 165.68 1491.12 12.426 258.02216 279.1265 287.0406 284.4025602 260.6602 373.03349Offi ce 7 132.98 1196.82 9.9735 207.09674 224.0357 230.3879 228.270476 209.2141 299.408459Vestibule 56.482 508.338 4.23615 87.962384 95.15706 97.85507 96.95573036 88.86172 127.170917Lobby 164.429 1479.861 12.332175 256.07391 277.0189 284.8732 282.2551217 258.692 370.216826Work Area 110.58 995.22 8.2935 172.21204 186.2977 191.5799 189.81914 173.9727 248.974187Janitor 70.81 637.29 5.31075 110.27613 119.2959 122.6783 121.5508528 111.4036 159.430839Bath 1 70.81 637.29 5.31075 110.27613 119.2959 122.6783 121.5508528 111.4036 159.430839Bath 2 70.81 637.29 5.31075 110.27613 119.2959 122.6783 121.5508528 111.4036 159.430839Break Room 247.82 2230.38 18.5865 385.9431 417.5104 429.3482 425.4022361 389.889 557.974165Conf. Room 534.36 4809.24 40.077 832.18688 900.2537 925.7787 917.2703529 840.6952 1203.12757Hallway 577.539 5197.851 43.315425 899.43181 972.9987 1000.586 991.3904528 908.6277 1300.34638

qsensible

Figure 15. Infiltration Calculations

Totals (1PM) sensible latent TotalOffi ce 1 5638.9344 531.9205526 6170.85498Offi ce 2 8156.6844 613.380908 8770.06532Offi ce 3 6079.1338 494.2299404 6573.36379Offi ce 4 5567.3179 443.16524 6010.48313Offi ce 5 5567.3179 443.16524 6010.48313Offi ce 6 7125.6692 573.0334904 7698.70269Offi ce 7 5289.0177 499.4084594 5788.42613Vestibule 1246.7369 127.1709175 1373.90777Lobby 6999.9426 570.2168264 7570.15944Work Area 4229.7787 248.9741874 4478.75287Janitor 1316.145 159.4308393 1475.57588Bath 1 1316.145 159.4308393 1475.57588Bath 2 1316.145 159.4308393 1475.57588Break Room 10174.578 2097.974165 12272.5524Conf. Room 6691.1808 1203.127571 7894.30837Hallway 7231.8622 1300.346385 8532.20855

SHRroom 0.8971433 Total CL 93570.9963 btu7.79758302 tons

Figure 16. Total Cooling load for every room

Page 15


Appendix B

Figure 17. Coil Sizing calculations

Page 16


Appendix C

No Q D dP/L L P v1 2401 20 0.1 9 0.000 12002 2401 20 0.1 5 0.005 12003 817 13 0.1 15.8 0.016 9504 738 12 0.1 4 0.004 9005 321 9 0.1 1 0.001 7506 417 10 0.1 3 0.003 8007 na na na na na na8 79 5 0.1 24 0.024 5009 na na na na na na

10 1584 16 0.1 21 0.021 110011 902 14 0.1 1 0.001 100012 611 12 0.1 2 0.002 90013 291 9 0.1 1 0.001 75014 320 10 0.1 4 0.004 80015 291 9 0.1 7 0.007 75016 682 12 0.1 33 0.033 90017 296 9 0.1 1 0.001 75018 386 10 0.1 5 0.005 800

Figure 18. Pipes diameters, air flow, pressure loss and air velocity

Page 17


fittings pipe size Le Pn/a n/a n/a 0.000

90 13 16.25 0.01690 10 12.50 0.01390 5 6.25 0.00690 9 11.25 0.01190 12 15.00 0.015

III 13 21.67 0.022branch IV 12 8.00 0.008branch IIX 5 8.33 0.008branch V 9 30.00 0.030branch VI 10 6.67 0.007X 16 26.67 0.027

45 16 12.00 0.012XI 14 9.33 0.009XII 12 8.00 0.008XIII 9 30.00 0.030XIV 10 6.67 0.007XV 9 30.00 0.030XVI 12 40.00 0.040XVII 9 30.00 0.030XIIX 10 6.67 0.007Entrance 20 20.00 0.020

Figure 19. Minor Losses Calculations

Room Major losses Minor losses Total lossesVestibule 0.045 0.097 0.142Offi ce 1 0.026 0.127 0.153Offi ce 2 0.028 0.118 0.146Offi ce 3 0.033 0.099 0.132Offi ce 4 0.030 0.121 0.151Offi ce 5 0.034 0.124 0.158Offi ce 6 0.064 0.131 0.195Offi ce 7 0.060 0.153 0.213

Figure 20. Total Losses

Page 18


Pipe DP Need Damper 1 C1 D/Do Diameter Angle P1 c2 D/Do Diameter Angle P2Vestibule 0.071 on 3 0.94 0.6 7.8 75 0.195 0.195Offi ce 1 0.060 on 3 0.94 0.6 7.8 75 0.206 0.206Offi ce 2 0.067 on 3 0.94 0.6 7.8 75 0.199 0.199Offi ce 3 0.081 on 11, on 14 0.86 0.5 5 60 0.186 0.49 0.5 5 30 0.206Offi ce 4 0.062 on 11 0.86 0.5 4.5 60 0.205 0.205Offi ce 5 0.055 on 11 0.86 0.5 4.5 60 0.212 0.212Offi ce 6 0.018 on 18 0.45 0.8 8 10 0.213 0.213Offi ce 7 0.000 on 17 n/a n/a n/a n/a 0.213 0.213

Dampers Configurations and Total Pressure Losses w/ Dampers

Figure 21.Damper Calculations and Pressure loss on pipes after

Page 19


Appendix D

Figure 22. Major & Minor Pressure loss Calculations

Page 20


Figure 23. Total Pipe Loss and Total Pressure Loss Calculations

Figure 24. Damper Configuration and Pressure loss on each exit after dampers

Page 21


Appendix E

Pipes

Diameter(in) Lenght(ft) Cost Total Cost20 18 6.566667 118.218 1 4.725 4.72514 13.4 3.1 41.5412 73.9 2.1 155.1910 39.9 1.7826 71.125749 12 1.7226 20.67125 31.4 0.7726 24.2596413(est.) 15.8 2.6 41.0816(est.) 17.1 3.8 64.98

541.7716Tees

Dimensions Quantity Cost/unit Total Cost20x20x20 2 29.415 58.8318x18x18 1 29.262 29.26216x16x16(est.) 1 29 2914x14x14(est.) 1 28.5 28.512x12x12(est.) 3 28 8413x13x13(est.) 1 27.5 27.5

257.092

Elbows

Dimensions Quantity Cost/unit Total Cost13(est.) 1 6 612 2 5.373 10.74610 2 3.28 6.569(est.) 2 3 65(est.) 1 2.2 2.2

31.506Dampers

8 5 3.062 15.316 1 2.354 2.3545 5 1.846 9.234 2 1.292 2.584

29.478Takeoff(entrance)

20(est.) 2 22.5 45

Reducers

20x18 4 15.969 63.87618x16 5 11.571 57.85516x14 6 9.186 55.11614x13(est.) 1 8.5 8.514x12(est.) 2 8 1613x12(est.) 2 7.5 1512x10(est.) 7 7 4910x9(est.) 5 6.8 3410x8(est.) 1 6.5 6.58x6(est.) 1 6 66x5(est.) 1 5.8 5.8

317.647

45°Wye

14x12x5 2 31.18 62.3614x10x10 1 31.18 31.1812x12x5 1 26.81 26.8112x10x9 1 26.81 26.81

147.16

Units Price2 7989.9

Total Cost: 9330.08

Page 22

ac report

Documents

cooling system

cooling units

quantity of air

cooling solution

cooling load summary5

tons of cooling capacity

air quantity ratio

maximum air quantity