MCQ in Refrigeration Engineering Part 5 | ME Board Exam

(Last Updated On: December 26, 2020)

This is the Multiple Choice Questions Part 5 of the Series in Refrigeration Engineering as one of the Mechanical Engineering topic. In Preparation for the ME Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Exam Questions in Mechanical Engineering field, Mechanical Engineering Books, Journals and other ME References. I assume you are looking for a reviewer that will help you achieve your goal to become a License Mechanical Engineer very soon. Yes, you are in the right place to make your dream come true. Make sure to familiarize each and every questions to increase the chance of passing the Mechanical Board Examination.

MCQ Topic Outline included in ME Board Exam Syllabi

• MCQ in Principles of Different Refrigeration Systems
• MCQ in Determination of Cooling Loads
• MCQ in Basic Design of Ice Plants, Cold Storage and Skating Rinks
• MCQ in Instrumentation and Controls

Continue Practice Exam Test Questions Part 5 of the Series

⇐ MCQ in Refrigeration Engineering Part 4 | ME Board Exam

Choose the letter of the best answer in each questions.

201. Which of the following is the most appropriate definition of latent heat?

A. Heat remove to melt ice

B. Heat removed to change temperature of a substance

C. Heat added to change temperature of a substance

D. Heat added to change the state of a substance

202. If the compressor discharge becomes frosted, the probable cause would be ______________

A. Refrigerant flooding back

B. Expansion valve improperly set

C. Too much cooling water

D. Insufficient cooling water

203. The low-pressure control switch:

A. Is a safety device

B. Actuates the cooling water

C. Cuts out the compressor to maintain proper flow

D. Regulates the king valve

204. Which of the following is an indications of faulty Freon compressor valves?

A. Compressor runs continuously

B. Low head pressure – high suction pressure

C. Gradual or sudden decrease in capacity

D. Any of these

205. What is the probable cause if a compressor runs continuously?

A. A clogged condenser

B. Insufficient refrigerant

C. Faulty cooling water valve

D. Any of these

206. To test a thermostatic valve, immerse the bulb in:

A. Crushed ice

B. Hot water

C. Oil

D. none of these

207. If a compartment requires the removal of 36,000 Btu per hour, how much is the necessary compressor capacity?

A. 6 tons

B. 3 tons

C. 2 tons

D. 1 ton

208. Which of the following must be done to eliminate frost on the discharge pipe of the compressor?

A. Open the expansion valve

B. Regulate water to the condenser

C. Crack bypass valve

D. None of these

209. The following are standard characteristics of Freon -11 except:

A. Non-toxic

B. Separates from water

C. Boiling point over 200˚F

D. Very volatile

210. Which of the following type valves are not found on a Freon -12 system?

A. Bellows

B. Duplex

C. Diaphragm

D. Single packed

211. How much will be removed be one-ton refrigeration unit?

A. 200 Btu per min.

B. 144 Btu per min.

C. 400 Btu per min.

D. 2000 Btu per min.

212. Which of the following is the primary purpose of the evaporator?

A. Transmit latent heat of fusion

B. Transmit latent heat of evaporation

C. Absorb latent heat of fusion

D. Absorb latent heat of evaporation

213. An automatically controlled Freon -12 compressor will start when the__________.

A. Expansion valve opens

B. Solenoid valve opens

C. Expansion valve closes

D. Solenoid valve closes

214. A single trunk piston-type compressor is undesirable for a Freon unit because the:

A. Lubricant mixes with the refrigerant

B. Refrigerant reduces the crankcase pressure

C. Lubricant temperature becomes excessive

D. Refrigerant becomes superheated

215. Calcium chloride is sometimes used in refrigeration system as a:

A. Refrigerant

B. Lubricant

C. Primary coolant

D. Secondary coolant

216. When the outlet temperature of the evaporator exceeds the inlet temperature the condition is called ____________.

A. Boiling

B. Superheating

C. Melting

D. freezing

217. Which of the following refrigerants would give the most trouble when operating with warm circulating water?

A. Freon -12

B. CO₂

C. Ammonia

D. Ethyl chloride

218. As Freon leaves the expansion valve:

A. Pressure increases – volume increases

B. Pressure decreases –volume increases

C. Pressure decreases – volume decreases

D. Pressure increases – volume decreases

219. The suction pressure switch is actuated by:

A. Pressure on a bellows

B. Temperature on a bellows

C. A thermo-pressure regulator

D. A thermostatic temperature device

220. A thermometer senses which of the following?

A. Latent heat

B. Sensible heat

C. Heat of fusion

D. Specific heat

221. Five pounds of water heated to raise the temperature 2˚F requires how many Btu?

A. 20 Btu

B. 5 Btu

C. 2 Btu

D. 10 Btu

222. Superheat is heat added___________.

A. In changing liquid to vapor

B. After all liquid has been changed to vapor

C. To increase pressure

D. To increase temperature

223. The expansion valve does not seem to be operating properly. There is high superheat. Test by listening to the sound of Freon flooding through the tubes and _______.

A. Warm bulb with hand

B. Place bulb in cold water

C. Place bulb in hot water

D. Any of these

224. What do you call a material in a dryer?

A. Drain

B. dryer

C. Desiccant

D. A or C

225. What is the main function of a receiver?

A. Separate the oil from the refrigerant

B. Cool the hot gases

C. Store the refrigerant

D. Condense the refrigerant

226. During the re-expansion portion of the refrigeration compressor cycle

A. The suction valve is open

B. The suction valve is closed

C. The discharge valve is closed

D. B and C

227. Absolute zero on the Fahrenheit scale is equal to :

A. -273˚

B. -460˚

C. 0˚

D. -100˚

228. A quick method of detecting a leaky condenser on a freon system would be to___________.

A. Compare temperatures and pressures

B. Test circulating water with proper chemicals

C. Open vent on head and test with halide torch

D. Use soapsuds on condenser outlet fittings

229. Which of the following is not a characteristic of Freon-12?

A. Corrosive

B. Non-inflammable

C. Odorless

D. Boiling point -12˚F

230. In the discharge line between the compressor and the condenser one would find:

A. High pressure, high temperature gas

B. High pressure, low temperature liquid

C. High temperature, high pressure liquid

D. High pressure, low temperature gas

231. For a low speed compressor the belt drive is preferred to the direct drive because it:

A. Eliminates the use of mineral lubricating oils

B. Permits the use of a smaller high-speed motor

C. Absorbs torsional vibration

D. Reduces the number of automatic controls

232. Refrigerant leakage from the compressor crankcase is prevented by

A. Using skirt type pistons

B. Maintaining a vacuum in the crankcase

C. Using shaft seals

D. Using lanterns rings

233. The heat used to change a liquid to a gas or vapor is called latent heat of

A. Absorption

B. Vaporization

C. Fusion

D. liquid

234. What is the compression ratio of a refrigerator compressor?

A. The ratio of the absolute suction pressure to the absolute discharge pressure

B. The ration of the absolute discharge pressure to the absolute suction pressure

C. The ratio of the excessive liquid refrigerant in the receiver to that in the system

D. None of these

235. The thermostatic expansion valve is designed to maintain a constant________.

A. Superheat

B. Flow

C. Pressure

D. temperature

236. A refrigerant gives up heat when it

A. Vaporizes

B. Evaporates

C. Condenses

D. boils

237. The cooling component of a refrigeration cycle is called ______.

A. A receiver

B. An evaporator

C. A condenser

D. A desiccant

238. When ordering an expansion valve which of the following information in necessary?

A. Size and pressure

B. Size, tonnage, temperature and pressure

C. Pressure and temperature

D. Size and tonnage

239. A hot crankcase and cylinder head accompanied by a low suction pressure would be caused by

A. Excess refrigerant

B. Insufficient refrigerant

C. Air in the system

D. Stuck discharge valve

240. Which of the following characteristics that is not desirable in a refrigerant?

A. Low latent heat of fusion

B. High latent heat of vaporization

C. Low latent heat of vaporization

D. A and C

241. The principle of the centrifugal system is based on which of the following?

A. Kinetic energy

B. Potential energy

C. Lenz’s law

D. Boyle’s law

242. The temperature in the vegetable box should be approximately

A. -5˚F

B. 20˚F

C. 38˚F

D. 10˚F

243. The compressor will run continuously if there is

A. Insufficient refrigerant

B. Air in the system

C. Too heavy

D. Any of these

244. A “direct” refrigeration system is one in which:

A. Ice is used for cooling

B. A secondary coolant is pumped through the evaporator coils

C. The refrigerant passes through coils in the evaporator

D. Any of these

245. A “CARRIENE” is a type of:

A. Refrigerant oil

B. Refrigerant

C. Scale cleaner

D. None of these

246. What is the first step that must be don when securing a system?

A. Open bypass valve

B. Close receiver (king) valve

C. Open solenoid valve

D. Cut out compressor on high pressure

247. When securing a Freon-12 system for repairs

A. Open the line at 1 to 2 pounds pressure

B. Open the line at 5 to 10 pounds pressure

C. Pump down to a slight vacuum

D. Pump down to 10” vacuum

248. The most common reason for the small usage of CO₂ systems is:

A. It is too dangerous

B. Its upkeep is too high

C. The machinery is too heavy

D. It is too costly

249. To increase heat transfer in the evaporator

A. Increase suction pressure

B. Increase air circulation

C. defrost coils

D. B and C

250. When compressor is operated in short spurts after a lay-up or overhaul the purpose is to:

A. Allow refrigerant tome to circulate

B. Determine actual compressor oil level

C. Effect gradual cooling

D. None of these