Question

It is desired to air-condition a small one-room store located on the first floor of a building several stories in height. The store is 20' wide and 40' deep, and the ceiling height is 12'.The front wall, which faces north, may be condidered as 100% glass. The partitions between this store and the stores on either side are 4" cinder tile, platered on both sides; and the rear wall, which contains 40 sq ft of glass, is of 4" brickbacked by 8" concrete blocks with furred metal lath and plaster on the inside surface. The floor construction consists of a 6" concrete slab with 1/8" asphalt tile flooring laid directly on the conconcrete. There is no ceiling in the basement. The store ceiling constructin consists of a 3" concrete slab with a suspended metal-lath and plaster ceiling below the supporting steel joist, and a double wood floor on sleepers above the slab. The store is to be kept at 80F and 50% relative humidity when the outside temperature is 95F and the relative humidity is 50%. The stores on either side are not airconditioned, nor are the offices on the floor above. The temperature in the basement may be assumed to be 7 1/2 deg warmer than the store. Assume that there will be an average of 20 persons in the store and that about 2,000 watts of fluorescent lighting will be used.

What are the coefficients of heat transmission for walls, ceiling, floor, and partitions?

Calculate the sensible heat gain of the store described . Do not include infiltration.

For the same store, find the number of pounds of fresh air needed per minute if 75% of the air is recirculated and 25% is fresh air.

Compute the number of tons of refrigeration required to air-condition the store.

Answer 1