Building Services Engineering 5th Edition Handbook

168 Ventilation and air conditioning
37. When the coefficient of performance during heating, COP H , of a vapour-compression refrigeration
cycles is 3, which of these is the correct compressor power input to generate 750 kW
of heating?
1. 750 kW.
2. 2250 kW.
3. 100 kW.
4. 250 kW.
5. 75 kW.
38. When the coefficient of performance during cooling, COP R , of a vapour-compression refrigeration
cycles is 2.25, which of these is the correct compressor power input to generate
225 kW of cooling?
1. 225 kW.
2. 22.5 kW.
3. 506 kW.
4. 100 kW.
5. 2.25 kW.
39. What does ventilating a building mean?
1. Maintaining indoor air circulation.
2. Exhausting room air to outdoors.
3. Minimum provision of 4 air changes/h.
4. Removal of moisture, odours and carbon dioxide from rooms.
5. Provision of adequate outdoor air into each room.
40. How should conditioned supply air enter a room?
1. Directed at the ceiling.
2. Directed at walls.
3. Should mix with room air outside the occupied room volume.
4. Strike the floor in walkways and mix with room air.
5. Diffuse imperceptibly with room air.
41. Which is a suitable design criterion for air conditioning?
1. Some manual control over air movement preferred.
2. Windows should always be openable.
3. Manual adjustment of air-conditioning system must be avoided.
4. Automatic comfort control essential for every occupant.
5. Sealed windows avoided as they always generate discomfort.
42. Which is correct about air filters?
1. Air filter air pressure drop reduces as dust load increases.
2. Increasing dust load in a filter causes no reduction in air flow to the rooms.
3. Air filtration at the air-handling unit completely stops atmospheric dust and dirt from
entering the building.
4. Increasing dust load in a filter reduces supply air flow rate.
5. A dirty air filter has an air pressure drop of around ten times that of a clean filter.