Homework #2

Review

Enthalpy

Interior design temperature 75F @ 50% RH Outside design temperature 98F @ 78F WB

75

.009

98

.017

.009

.017

75F @ 50% RH

98F @ 78F WB

Heat Gains from Infiltration LoadsCFM = (ACH X Vol.)/60 Btu h = 1.1 x CFM x TD

1.1 0.5 ACH 90,665 23

CFM = (ACH X Vol.)/60 Btu h = 4,500 x CFM x (Wroom – Woa)

4,500 0.5 ACH 90,665 0.009 0.017

Heat Gains from Outside Air for Ventilation LoadsCFM = (Rp x Occup.) Btu h = 1.1 x CFM x TD

1.1 7.5 50.00 23

CFM = (Rp x Occup.) Btu h = 4,500 x CFM x (Wroom – Woa)

4,500 7.5 50.00 0.009 0.017

Sensible and Latent Gains

sensibleload

latentload

conduction through roof, walls, windows, and skylightssolar radiation through windows, skylightsconduction through ceiling, interior partition walls, and floorpeoplelightsequipment/appliancesinfiltrationventilationsystem heat gains

cooling load components

Sensible Latent West Wall Group B

ea L /width Ht. less SF Sf of Area R value U value TETD /TD SC SHGC BTU h loss

Studs & plates @ Brick 120.00 9.83 16.70% 197.05 10.6 0.094 59 1,096.81Studs & plates w/o Brick 120.00 2.00 16.70% 40.08 7.47 0.134 59 316.56Window (a) 14 6.00 4.00 0 336.00 2.93 0.341 23 0.83 41 14,071.62Windows (b) 4 6.00 7.33 0 175.99 2.93 0.341 23 0.83 41 7,370.51Door 1 3.33 7.00 0 23.33 2.93 0.341 59 469.81Headers (Door & Wind.) 111.33 0.75 0 83.50 6.8 0.147 59 724.48Cavities @ bricks 1 120.00 8.67 815.88 224.04 24.93 0.040 59 530.23Cavities w/o bricks 1 120.00 2.00 0 240.00 19.32 0.052 59 732.92

Total 25,312.94

Heat Gains from Occupant LoadsBtu h = Sensible per occupant x number of occupants

Table 2-17 page 43 580.00 50.00 29,000.00Btu h = Latent per occupant x number of occupants

Table 2-17 page 43 870.00 50.00 43,500.00

Step #1 – Select Wall Type

Step #2

• Select Sun time• Select color of wall

– D = dark– L = light

• Select wall orientation

Step #3 – Read Value of TETD

For Windows

• Btuh = (U x A x TD) + (A x SC x SHGF)

• A= Area• TD = outdoor design – indoor design temp.• SC = shading coefficient • SHGF = solar heat gain factors

EQ Credit 8.1 - Daylighting

• ASHRAE Standard 90.1– 10% lighting load

credit for harvesting – 10% lighting load

credit for occupancy sensors