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 $20\text{'}$ wide and $40\text{'}$ deep, and the ceiling height is $12\text{'}.$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 $80$F and $50\%$

relative humidity when the outside temperature is $95$F 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 $71/2$ 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.$$