179. A classroom that normally contains 40 people is to be air-conditioned with window air-

conditioning units of 5 kW cooling capacity. A person at rest may be assumed to dissipate heat

at a rate about 360 kJ/hr. There are 10 light bulbs in the room, each with a rating of 100 watts.

The rate of heat transfer to the classroom through the walls and the windows is estimated to

be 15,000 kJ/hr. If the room is to be maintained at a constant temperature of 21°C, determine

the number of window air-conditioning units required.

A. 1 units B. 2 units

C. 3 units D. 4 units