Question

Which of the following statements are TRUE? ( the answer in half hour please ) 1) otary compressors are positive displacement; refrigerant is compressed due to movement of blades *
2)In all-air HVAC systems, the thermal energy transfer medium is water *

3)The evaporator is device used in the high pressure side of a refrigeration system *

4)The fan-coil unit can be placed in the room or exposed to occupants. It is used for heating and cooling *

5)Evaporative condenser is used only air as condensing medium to condense the hot vapour refrigerant *

6)Small houses and residential apartments needs equipment located inside the zone itself for cooling or heating *

7)Central HVAC system equipment can be an attractive benefit when considering its long service life *

8)Split system is type of central HVAC systems *

9)The first cost of decentralized HVAC system is affordable capital cost *

10)Water cooled condenser is used for large capacity plant *

11)When the compressor and motor operate on the same shaft and are enclosed in a common casing is known as (semi-hermetic sealed compressor) *

12)In the induced draft cooling tower, the fan forces the air through the tower *

Answer 1

Answers are

1) True
Rotary compressors are positive displacement; refrigerant is compressed due to movement of blades. ( Positive displacement means a fixed volume of the fluid is compressed in each cycle)
  
3) False
The correct statement is,
In all-air HVAC systems, the thermal energy transfer medium is air.

3) False
The correct statement is,
The evaporator is device used in the low pressure side of a refrigeration system. (Condenser is used on high pressure side)

4) True
The fan-coil unit can be placed in the room or exposed to occupants. It is used for heating and cooling (The size of the unit is small)

5) False
The correct statement will be
Evaporative condenser uses both air and water as condensing medium to condense the hot vapour refrigerant

6) True
Small houses and residential apartments needs equipment located inside the zone itself for cooling or heating. ( If a room inside an apartment is considered, the air conditioning unit for that room will be located within apartment itself)

7) True
Central HVAC system equipment can be an attractive benefit when considering its long service life ( Although initial cost is high)

8) True
Split system is type of central HVAC systems ( Split system consists of two units; outdoor unit and indoor unit)

9) True
The first cost of decentralized HVAC system is affordable capital cost ( when compared to centralized system)

10) True
Water cooled condenser is used for large capacity plant ( This provides better heat transfer efficiency than air cooled condenser)

11) True
When the compressor and motor operate on the same shaft and are enclosed in a common casing is known as (semi-hermetic sealed compressor). It must be noted that the casing is bolted and not welded permanently. If the casing is welded, it is hermetically sealed compressor.

12) False
The correct statement would be,
In the induced draft cooling tower, the fan draws the air through the tower. The fan is located on top. In Forced draft cooling tower, air is forced by fan located at bottom.