REFRIGERATION & AIR

CONDITIONING -QUESTION

BANK

Short questions increase the

understanding and clarity to a

greater depth. It enables to apply

the fundamentals in real life. Searching

answers makes oneself confident.

REFRIGERATION

1. Thermodynamic properties of a refrigerant?

2.  Transport properties of a refrigerant?

3.  Chemical properties of a refrigerant?

4. Physical properties of a refrigerant?

5. Toxic properties of a refrigerant?

6. Economic properties of a refrigerant?

7. eco-friendly refrigerant?

8. Global Warming?

9. Ozone Depletion Potential of a refrigerant?

10. Clean Air Act of 1987 and 1990?

11. Montreal Protocol of 1987?

12. Kyoto Protocol of 1997?

13.  Deadline of using R-22?

14. Mixed refrigerant?

15. An accumulator

16. Internal Leakage of a refrigerant?

17. External Leakage of a refrigerant?

18. Evacuation and dehydration of a refrigeration unit?

19. Vacuum testing of a refrigeration unit?

20. Pressure testing of a refrigeration unit?

21.  Various methods of refrigerant Leak Detection?

22.  Halide Torch?

23. Electronic Leak Detector?

24. Soap Solution Leak Detection?

25. Super-heated vapor? Give examples.

26. What is a Gas? Give examples.

27. Difference between a gas and a super-heated vapor?

28. Receiver?

29.  Automatic expansion valve?

30.  Vapor absorption refrigeration?

31.  Absorbent?

32.  Aqua Heat Exchanger?

33.  Chilled water?

34. Water chilling unit?

35.  Electrolux refrigerator?

36.  Commonly used absorbents in vapor absorption refrigeration?

37.  Commonly used refrigerants in vapor absorption refrigeration?

38. Strong aqua?

39.  Weak aqua?

40. Analyzer?

41.  Rectifier?

42. Heat engine

43. Carnot cycle

44. Reversed Carnot cycle?

45. Rankine cycle?

46. reversed Rankine cycle?

47.  vapor compression refrigeration?

48. vapor compression refrigeration cycle?

49.  theoretical vapor compression refrigeration cycle?

50.  standard vapor compression refrigeration cycle?

51. actual vapor compression refrigeration cycle?

52. Compare a theoretical and standard vapor compression refrigeration cycles.

53. Compare a theoretical and actual vapor compression refrigeration cycles.

54. dry compression?

55. wet compression?

56. Why wet compression not possible in actual practice?

57.  Is isothermal compression not possible in vapor compression refrigeration?

58. Which one consumes less work in isothermal and isentropic compression?

59. Why isentropic compression used in vapor compression refrigeration?

60. heat pump?

61.  various important components of a vapor compression refrigeration cycle?

62.  refrigerating effect?

63. refrigerating capacity?

64.  heating effect?

65.  heating capacity?

66. coefficient of performance (COP)?

67.  unit of refrigeration?

68. super-heating?

69.  effect of super-heating on COP?

70. Why is large amount of super-heating not desirable?

71.  sub-cooling?

72. In which phase sub-cooling is possible?

73.  Applications of medium temperature refrigeration.

74. Few applications of low temperature refrigeration.

75. Natural refrigeration?

76. Various methods of refrigeration?

77.  Difference between mechanical and natural refrigeration?

78.   Mechanical refrigeration?

79. Effect of sub-cooling on COP?

80.  Is more of sub-cooling desirable?

81.  Effect of evaporator pressure (or temperature) increase/decrease on COP?

82.   Effect of condenser pressure (or temperature) increase/decrease on COP?

83.  Define refrigeration. List the various types of refrigeration.

84.   List a few applications of high temperature refrigeration.

85.  Why is throttling used in vapor compression refrigeration?

86. state the discharge pipe used in refrigeration?.

87. Explain the liquid pipe used in refrigeration.

88. Materials for the pipes used in refrigeration?

89. Can we use pipes of same material with all the refrigerants?

90. Tell specific volume.

91. Meaning by specific enthalpy.

92. Meant by specific entropy?

93. Explain specific internal energy?

94. Discuss volumetric displacement of a compressor?

95. Explain volumetric displacement of a compressor.

96. Discuss volumetric displacement of a turbine?

97. Explain clearance in a reciprocating compressor.

98. How clearance expressed in a reciprocating compressor?

99. What is volumetric efficiency of a compressor?

100. Explain is expression for volumetric efficiency of a compressor?

101. What is the total volumetric efficiency of a compressor?

102. Give the expression for the total volumetric efficiency of a compressor?

103. What is datum in refrigeration?

104. Give the normal boiling points of refrigerants R – 22, R – 134a and Ammonia?

105. Draw a pressure enthalpy chart for a refrigerant. Highlight the following lines on it.

106. Constant pressure lines

107. Isothermal temperature lines

108. Isentropic lines

109. Constant specific volume line

110. Isenthalpic lines

111. What is a sub-cooled liquid? Give examples.

112. Discuss a saturated liquid? Give examples.

113. Explain two phase saturated liquid and saturated vapor. Give examples.

114. Discuss a saturated vapor? Give examples.

115. What are various types of refrigerant leakages?

116. Discuss a primary refrigerant? Give examples.

117. What is a secondary refrigerant? Give examples.

118. Explain a tertiary refrigerant? Give examples.

119. What is super heating?

120. Explain sub-cooling?

121. What is suction pressure?

122. Give the meaning of discharge pressure?

123. Explain heat lost in the condenser?

124. Discuss capillary tube used as expansion valve in vapor compression refrigeration.

125. COMPRESSORS

126. Discuss the various types of compressors used in vapor compression refrigeration.

127. Where and why reciprocating compressor used in vapor compression refrigeration?

128. Discuss in brief rotary compressor used in vapor compression refrigeration?

129. Where and why centrifugal compressor used in vapor compression refrigeration

130. What is a condenser?

     1. Give the various types of condensers?

     2. What are various cooling mediums used in condensers?

     3. Discuss a natural air cooled condenser?

     4. Explain a forced air cooled condenser.

     5. Explain an evaporative condenser?

     6. List the various types of expansion valves used in refrigeration?

     7. What is a capillary tube?

     8. Where and why does a capillary tube used?

     9. What is an automatic expansion valve?

     10. Where and why does an automatic expansion valve used?

     11. What is a thermostatic expansion valve?

     12. Where and why does a thermostatic expansion valve used?

     13. What is a high-side float valve?

     14. Explain a high- side float as an expansion valve?

     15. What is a low-side float valve?

     16. Where and why does a low-side float used as expansion valve?

     17. What is an evaporator?

     18. Explain the various types of evaporators used in refrigeration?

     19. What is a dry evaporator?

     20. Discuss a flooded evaporator?

     21. What is an oil separator?

     22. Where does an oil separator installed in a refrigeration cycle?

     23. What is the need of a filter used in refrigeration cycle?

     24. What is need of a drier used in a refrigeration cycle?

     25. List some common used driers used in refrigeration.

     26. Why to use a lubricant in refrigeration?

     27. List the lubricant used in refrigeration.

     28. Can we use same lubricant with various compressors? If yes, why? If not, why not?

131. REFRIGERANTS

     1. What is a refrigerant?

        1. 1. Explain an Ideal refrigerant?

           2. Discuss an eco-friendly refrigerant?

           3. What is a primary refrigerant?

           4. Give some examples of primary refrigerant?

           5. What is a secondary refrigerant?

           6. Give some examples of secondary refrigerant?

           7. What is a tertiary refrigerant?

           8. Give some examples of tertiary refrigerant?

           9. What is a suction pipe in refrigeration

           10. Explain multi-evaporator refrigeration? Where does it used in actual life?

           11. Discuss refrigerant lubricant oil miscibility? Is this miscibility desirable or not and why?

           12. What is a low pressure cut-out? Where does it installed in the refrigeration circuit and why?

           13. Explain a high pressure cut-out? Where does it installed in the refrigeration circuit and why?

           14. What is a thermostat? Where does it installed in the refrigeration circuit and why?

           15. Explain an overload protector? Where does it installed in the refrigeration circuit and why?

           16. What is a solenoid valve? Where does it installed in the refrigeration circuit and why?

           17. Define a liquid suction heat exchanger? Where does it installed in the refrigeration circuit and why?

           18.  What is a receiver in a refrigeration circuit? Where does it installed in the refrigeration circuit and why?

           19. Discuss a drier cum filter? Where does it installed in the refrigeration circuit and why?

           20. What is a capillary tube? Where does it installed in the refrigeration circuit and why?

           21. Discuss a thermostatic expansion valve? Where does it installed in the refrigeration circuit and why?

           22. What is a dry evaporator?

           23. Explain a flooded evaporator?

           24. What is an accumulator? Where does it installed in the refrigeration circuit and why?

           25. Explain an air cooled condenser? when does it used?

           26. Discuss a water cooled condenser. when does it used?

           27. Explain an evaporative cooled condenser? when does it used?

           28. Explain Cascade refrigeration?

           29. Discuss a Cascade Heat Exchanger?

           30. What is the lowest temperature achievable with Cascade Refrigeration?

           31. Explain multi-compressor refrigeration?

           32. What is a Flash Chamber?

           33. Explain the disadvantages of using Single Stage Compression in place of Multi-Compression Refrigeration?

           34. What is the difference between Inter-cooling and Flash Inter-cooling?

           35. Discuss centrifugal compression refrigeration?

           36. What is vortex tube refrigeration?

132. 2. Psychrometry

134. Define Psychrometry

135. Define an apparatus dew point?

136. What is an effective room sensible heat factor?

137. Define sensible heat load?

138. What is a latent heat load?

139. Define effective temperature?

140. Define is a specific humidity?

141. Discuss an adiabatic saturation?

142. What is effect on relative humidity with increase of dry bulb temperature?

143. Explain heating and humidification?

144. Meaning of cooling and dehumidification?

145. Discuss heating and dehumidification?

146. What is cooling and humidification?

147. Meaning of chemical dehumidification?

148. Discuss is adiabatic saturation?

149. What is moist air?

150. Explain a sling psychrometer?

151. Discuss Psychrometric processes?

152. What is specific volume of moist air?

153. Explain a psychrometric process? Why is this required?

154. List the various psychrometric processes.

155. Where is cooling and dehumidification of air used?

156. Give the application where heating and humidification of air used?

157. Mention reference temperature used in solving air conditioning problems?

159. Air Conditioning

160. List various types of air conditioning?

161. What are inside design conditions?

162. Define outside design conditions?

163. Discuss sensible heat load?

164. What is a latent heat load?

165. Give the meaning of grand sensible heat load?

166. What is a grand latent heat load?

167. Define a grand sensible heat factor?

168. What is an infiltration heat load?

169. Discuss  ventilation heat load?

170. What is an additional infiltration heat load?

171. Explain room sensible heat load?

172. What is room latent heat load?

173. Mention the meaning of room sensible heat factor?

174. What is a bypass factor for a cooling coil?

175. Explain the bypass factor for a heating coil?

176. What is a contact factor for a cooling coil?

177. Explain contact factor for a heating coil?

178. What is Apparatus Dew Point?

179. Give the meaning of supply air condition?

180. What is effective room sensible heat load?

181. Explain effective room latent heat load?

182. What is effective room sensible heat factor?

183. Meaning of sensible cooling?

184. What is sensible heating?

185. Explain an alignment circle on Psychrometric chart?

186. What are comfortable conditions?

187. Explain is a comfort zone?

188. What is an effective temperature?

189. List comfortable conditions?

190. What is a damper?

191.  Discuss a filter?

192. What is difference between a fan and a blower?

193. ABSORPTION REFRIGERATION

194. (i) What is an Analyzer?

195. (ii) Explain a rectifier?

196. (iii) What is a Generator?

197. (iv)Compare vapor compression and vapor absorption refrigeration.

198. (v) What is Electrolux refrigerator?

199. (vi) Explain a chilling unit.

200. THERMO-ELECTRIC REFRIGERATION

201. (i) What is thermo-electric refrigeration?

202. (ii) Explain a Thermo-couple? Give Examples.

203. (iii) What is a Semi-Conductor? Give Examples.

204. (iv) Define a Positive Semi-Conductor? Give Examples.

205. (v) What is a Negative Semi-Conductor? Give Examples.

206. (vi) Define Figure of Merit?

208.  STEAM JET REFRIGERATION

209. (i) What is steam jet refrigeration?

210. (ii) Explain  a steam Jet?

211. (iii) Discuss efficiency of a nozzle?

212. (iv) Define efficiency of entrainment of a nozzle?

213. (v) Discuss efficiency of a compressor? 

214. 6. APPLICATIONS

215. (i) Which are the practical applications of Cascade Refrigeration?

216. (ii) Mention the practical applications of Steam-Jet Refrigeration?

217. (iii) Which are the practical applications of Vortex Tube Refrigeration?

218. (iv) Mention the practical applications of Centrifugal Refrigeration?

219. (v) Which are the practical applications of Vapor Compression Refrigeration?

220. (vi) Mention the practical applications of Vapor Absorption Refrigeration?

221. (vii) Which are the practical applications of Thermo-electric Refrigeration?

222. 7. LIQUEFACTION OF GASES

223. (i) What is Joule Thomson Coefficient? What are its units? Where does it used and why?

224. (ii) Why is Joule Thomson Coefficient positive?

225. (iii) Explain negative Joule Thomson Coefficient.

226. (iv) Why is Joule Thomson Coefficient zero?

227. (v) What is an inversion temperature?

228. (vi) Explain the principle of liquefaction of gases?

229. (vii) What is liquefaction of gases?

230. (viii) Which are the different methods of liquefaction of gases? Which one is better and why?

231. (ix) What is magnetic cooling? Give the minimum temperature achieved by this method?

     https://www.mesubjects.net/wp-admin/post.php?post=3109&action=edit         Q. ANS Refrigerants https://www.mesubjects.net/wp-admin/post.php?post=3094&action=edit  Q. Ans Psychrometry                       https://mesubjects.net/wp-admin/post.php?post=3335&action=edit           Q. ANS. Cooling Loads