Heat Transfer, Refrigeration and Air Conditioning MCQs Archives

161. The process of heat transfer from one particle of the fluid to another by the actual movement of the fluid particles due to difference of density caused by temperature of the particle is known as

conduction

free convection

forced convection

radiation

✅ The correct answer is option B.

162. Which of the following statement is correct for ammonia as a refrigerant?

It is toxic to mucous membranes.

it requires large displacement per TR compared to fluoro carbons.

It reacts with copper and its alloys.

all of these

✅ The correct answer is option D.

163. Dehydration is the process of removing water vapour from the surrounding air.

TRUE

FALSE

✅ The correct answer is option A.

164. During heating and dehumidification process, dry bulb temperature

remains constant

increases

decreases

✅ The correct answer is option B.

165. Bell-Coleman cycle is a

reversed Carnot cycle

reversed Otto cycle

reversed Joule cycle

reversed Rankine cycle

✅ The correct answer is option C.

166. The specific humidity during humidification process

remains constant

increases

decreases

✅ The correct answer is option B.

167. In a vapour compression system, the condition of refrigerant before entering the expansion or throttle valve is

high pressure saturated liquid

wet vapour

very wet vapour

dry vapour

✅ The correct answer is option A.

168. For a given dry bulb temperature, as the relative humidity __________ the wet bulb temperature will increase.

increases

decreases

✅ The correct answer is option B.

169. Hydrogen is used in electrolux refrigeration system so as to __________ the rate of evaporation of the liquid ammonia passing through the evaporator.

equalise

reduce

increase

✅ The correct answer is option C.

170. A thermostatic expansion valve in a refrigeration system

ensures the evaporator completely filled with refrigerant of the load

is suitable only for constant load systems

maintains different temperatures in evaporator in proportion to load

none of the above

✅ The correct answer is option A.