Answer Happy

Calculate the HEAT GAIN of the given office building, Use the tables and the charts from the hand-outs on the referenced pages. DESIGN CONDITIONS Maps show a summer dry-bulb temperature of 95°F and a wet-bulb temperature of 76°F (Figures 15.17 and 15.18, location "O"). Desired indoor conditions are 75°F and 50% relative humidity. Time of peak heat gain is estimated as 4 PM. Temperature difference (TD) - 20. Grain difference (GD) -40 (p. 216). See Figure 15.21 for the example office building plan. Refer to Figure 15.22 for construction details. QUANTITIES Outdoor air: Use largest value. Infiltration at 0.5 air changes per hour - 1,980 CFM. (21.600) (11)(0.5) - 60 - 1.980. Ventilation at 15 CFM per person = 2.400 CFM. (160)(15) - 2.400 (pp. 202 and 203) Glaw: 1.030 sq. ft. face north (includes 70 sq. ft. of glass door area): 1.440 sq. ft. face south. Ligbting: Totals 64.800 watts at 3 watts per sq. ft. People: Each occupant produces 250 BTUH sensible plus 150 BTUH latent (p. 218). Ceiling-roof: Area is 10,800 sq. ft. Wall: Net wall area is Doors Area - 70 sq. ft. Equipment: Allow 21,600 watts at 1 watt per sq. ft.: plus 10 hp for air handler fans. PROJECT CONDITIONS Outdoor air: Select largest of infiltration at 0.5 air changes per hour or ventilation at 15 CFM per person (pp. 202 and 203). Glaw: Double glass U - The SC (shading coefficient) for clear double glass is (p. 215). Lighting: Estimate high, 3 watts per sq. ft. of floor area for this office occupancy, and revise as necessary after completing lighting design. Office building lighting installations can range from 1 to 5 watts per sq. ft. depending on luminous intensity, lamp type, and fixture design (pp. 215-216). People: 160 occupants seated doing light work. Ceiling-roof: U-0.05; weight is 7 pounds per sq. ft.; color is light: ETD - 36 (p. 215). Wall: U weight is 45 pounds per sq. ft.: color is dark. The west wall is hot at 4 PM: its ETD is 40: the weighted average ETD for all walls at 4 PM is 23 (p. 215). Dooru. U (tempered single glass). Solar gain for doors is included in Glau. Equipment: Allow watt per sq. ft. for electrical equipment operating at the time of peak heat gain. Also allow 10 hp for air handler fans. SUMMER HEAT GAIN = BTUH Insert appropriate factors and temperature differ- ence: then complete calculations and total BTUH. Add 10% if ducts are located outside the conditioned zone. Refer back to the heat loss example on page 000 for more detail

Roof 3" urethane on stl. deck AL II LU) EUUUUmmai UUN VI • Wall 4" brick, 2"air space, V2"gbd. sheathing, R-!! insulation, 720 1 14.00 Hi Office 160 occuponts 150 -Windows Windouis " TYP. FLRt. FLR. 4.0 high, fixed d6l. glass Soffit Sill Similar to walls 210' Plan FIGURE 15.11 Construction FIGURE 15.12

Door area sgt calastakord by dulo project name location floor area sqft calculated by date Design Conditions: Project Conditions: winter Outdoor Air, calculate 182 below but use only the largest CEM value: indoor 1. Infiltration based on air change rate winter summer Fob outdoor 2. Ventilation based on CFM per person TD Glass Uvalue_ SC (Shading Coefficient) "Fob outdoor Lighting total watts operating at peak heat gain time "Fdb indoor People total occupants at peak heat gain time TD "Fwb outdoor Walls U value color weight (lbs/sqft) % RH indoor Floor_ value. Door__U value, Slab Edge U value GD - Watts or hp. Appliances time of peak gain Other Item Quantities Winter Heat Loss - BTUH Summer Heat Gain = BTUH Outdoor Air winter _CFM (1.1) L TD) - - summer CFM Glass total - LUC_TD) - _ sqft (1.1) (0.68) sqft horiz sqft sqft Lighting People watts Celling.Roof Walls Floor bsmt C sons) latent) - UMTETD)- LUCTETD)- UTD UN factor factor sati sqft ee.. eeee _UN C D above grade Slab Edge Doors Equipment 23 LUC LUCTD CULTD] IIIIIIIIII IIIIIIII IIIIIIIII (34) LUCTD) - (2500) - sensible) L atent) Appliances Other 1 Subtotals 1 ducts are outside the conditioned space add 10% TOTAL BTUH heat loss heat gain Check; heat loss - 20-60 BTUH porsqft (south to north): heat gain - 15-60 BTUH person (north to south). Allow 4% of area served for fan rooms, and 2% of gross building won for central plantequipment