Q-1

The following data were obtained by a heating engineer during a survey of a client's office in New York City. The only heat loss is through one wall facing north. The exposed wall measures 20 by 10 ft. The wall has one single pane, 1/8-in. thick window, 20 sq ft in area. The wall is constructed of 4-in. face brick, 4-in. common brick, 1-in. air space, 3/4 in. wood fiber insulating board (density 15 lb per cu ft), 3/8-in. gypsum lath on 2- by 4-in. studs, and 1/2-in. plaster. The outside design temperature is 0 F and the inside temperature is to be 70 F. Infiltration is assumed to be 10 cfm.

1. Calculate the room heat loss.

2. How many pounds of saturated steam at 2 psig are required to maintain temperature of 70 F?

3. How much air at 100 F is required to heat the room?

4. What is the temperature in the 3 5/8-in. air space (4-in. stud space)?

Q-2

A pitched roof construction of asbestos shingles on roofing felt plus wood sheathing has an over-all coefficient of 0.01 Btu/(hr)(sq ft)( F). The roof area is 1,000 sq ft. The ceiling, with an area of 600 sq ft, is made up of 3/4 in. of gypsum lath and plaster having a conductance of 1.80 Btu/(hr)(sq ft)( F) for thickness stated, plus 2 in. of mineral wool having a conductivity of 0.27 Btu/(hr)(sq ft)( F) for 1-in. thickness. Inside and outside film conductances are 1.65 and 6.0, respectively. Outdoor temperature is plus 10 F. Indoor...