HVAC Load

DAR CONSULTING ENGINEERS HVAC Load Calculation

Input

Load on Roof

maximum ambient temperature @ Summer

50 degree C

Relative humidity % considered

35

desired temperature in warehouse

Composition of Wall 1,2,4

rib panel + polyurethane foam + metal sheet

thickness of wall mm

rib panel

metal sheet 1 + polyurethane + metal sheet 2

composition of roof

186

Solution

ft thermal Resistance (hr. ft2 F / Btu) expanded board stock (hr. ft2 F / Btu)

wall 1

134.51

9.5

ft

0.61024

0.031168

thermal conductivity

.7 kw/m.k

0.33

(Btu / ft hr. F)

0.40445

thermal 11 Resistance (hr. ft2 1.50881444 F / Btu)

metal sheet 1

thickness of wall mm

36.417

thickness (X) mm

0.55

ft

Area (ft2)

4898.45067

thermal conductivity (Btu / ft hr. F)

perimeter, m

164

36.921

perimeter, Ft

538.06

thermal Resistance (hr. ft F / Btu)

expanded board stock (hr. ft2 F / Btu)

T outside (F)

122

T (inside) (F) delta T

77 45

cooling load of wall 3

4.88746E-05

Toutside

6.22031E-05

11

11.33004887

Tinside delta T (F) Area (ft2)

overall heat transfer coefficient (Btu /Ft2 hr F)

U = 1/R

metal sheet 2 thickness of wall mm 27 4898.7

Q = UA delta T 87661.4755

heat load for wall 1

ft

0.0016404

thermal conductivity (Btu / ft hr. F)

4.443E-05

total resistance R overall heat transfer coefficient (Btu /Ft2 hr F)

U = 1/R total load around walls (1,2,3,4) Btu / hr Q = UA detla T Btu / hr since wall 2 & 4 are of similar size as that of wall 1. therefore total heat load is given by: (Btu / hr)

total load due to wall and roof Btu / hr

146027.5816

Area (ft2) delta T

19455.36887

3 * wall 1

Q = UA detla T Btu / hr

58366.1066

220047.7731

0.5

0.088260873 Q 87661.475 (Btu / hr)

in tons

18.33731443

1.28

floor arear, ft2

18094

delta T (F)

25

U=1/R

0.78125

Q (Btu/hr) 353398.4375

2

0.0018045 36.921

2.12

0.0022966

U = 1/R ft thermal conductivity (Btu / ft hr. F) thermal Resistance (hr. ft2 F / Btu) total resistance R

or from UAdelta T for concrete, R value of F2 = Heat Loss floor of 12" Coffiecient concrete masony unit

0.7

Metal Sheet overall heat transfer coefficient (Btu 0.66277202 /Ft2 hr F)

Q= F2 * Perimeter * detla T

from internet F2 for pured concrte wall (Btu/hr F /Ft)

35 thickness (X) mm

height (ft)

concrete

25 Degree C

Relative Humidity % (from handbook)

length (ft)

Composition of Wall 3

Floor Load

11.00010663

0.09090821 18094 45

74020.19155

delta T

25

Q floor (Btu/hr)

28517

in tons

2.3764

Q (tons)

29.44986979

Infiltration ventilation Load

latent heat load area of floor ft

QL =60Qρ∆w(1061+.444t) for warehouse, flow is considered Cfm/sf

5

floor area, ft2

so, volume flow rate Q (ft3/min)

Q (cfm/sf)

0.06

height of building (ft)

ρ (lb/ft3)

0.075

volume , ft3

18094

W (@ out side temperature)

0.027716

90470

W (@ inside temperature)

0.0068845

from engineering toolbox website, for floor, ACH/hr is given

∆W

0.0208315

Q (cfm)

t (AVERAGE TEMPERATURE) F

99.5

5428200 in ft3/hr delta T (F) now sensible heat load Qs (Btu/hr)

2

18094

infiltration sensible load

36.417

Qsensible (Btu/hr)

Qsensible = 0.91 * cfm * TD

899438.3553

658929.198

Qlatent = 0.68 * cfm * Q= ACH*(V/60)

Latent Load

2

GD*7000

Qlatent (Btu/hr)

2177935.396

total (Btu/hr)

3077373.751

21964.3066

0.0208315

∆W 45 1.1 * Q * delta T

now sensible heat load Qs (Btu/hr)

4478265

in tons

QL (Btu/hr)

6.216079187

total (sensible and latent) (Btu/hr)

4478271.216

in tons

watt*Ful*Fsa

appliance/ equipment load QS

qinput * usage factor (CLF)

QL

qinput * load factor (CLF)

256.4478126

373.189268

PEOPLE, LIGHT AND EQUIPMENT LOAD PEOPLE

N(sensible heat gain)*CLF

total peoples

90.47

light load Q

Where, Ful is light use factor Fsa special allowance factor

5 people per 1000 SF Ref:Pg 64 of handbook total floor space (area) sf

18094

North

load per person (Btu/hr) based on ref:

234

so, personal load is (Btu/hr)

21294

total floor space sf

18094

load for one computer watt

530

total watts

28950.4

total load (watt)

5300

98783

total printer considered

4

load/per printer (watt)

4700

total load (watt) total copier load watt other miscellaneous items considered

18800 1 6600

in Btu/hr

271867

W

in tons

22.65558333

Noon

1.6

total no of computer considered

10

card reader, card puncher, barcode printer, water cooler, paper shredder etc.

41 M

height considered 11.1 M

13785

11.1 M

so, total load uptill now

4998703

Sun Rise

or from handbook Pg 106: light load for warehouse watt/sf

total load people + light + appliance Btu/hr

E

in tons

416.5586

total load watt

44485

in Btu/hr

151790

41 M Sun Set

duct losses (10% of sensible load)

total load (Btu/Hr)

499870.3169

5498573.5 in tons

458.214457

1- It is mentioned in provided data that wall rib panels are already painted but no further details are provided. So the the effet is combienly taken in calculation 2- Wind direction and speed not found. 3- No insulation is there. 4- Ventilation load is calculated 5- No glass is considered. 6- Cooling load is calculated considereing maximum temperature in a day.