Question 121Refrigeration & AC - QMED

The correct answer is D) all of the above. Capacity control of a centrifugal refrigeration compressor can be accomplished by varying the speed of the compressor (option A), varying the position of the suction inlet damper vanes (option B), or varying the position of the hot gas bypass valve (option C). All three of these methods are used to adjust the capacity of the compressor to match the cooling load requirements, making D) all of the above the correct answer. The other options are incorrect because they only address one of the possible methods for capacity control, while the compressor can utilize a combination of these techniques to optimize its performance and efficiency.