Final answer:
Compressor capacity can be changed by adjusting the refrigerant flow rate, changing the compressor speed, or altering the compressor size; thus, all the listed methods are applicable.
Step-by-step explanation:
To match the system load, one can change the compressor capacity in several ways. These include:
- Adjusting the refrigerant flow rate to alter how much refrigerant is moved through the system.
- Changing the compressor speed which affects how quickly the compressor can compress the refrigerant, thereby affecting the system's cooling capacity.
- Altering the compressor size, which can be a more permanent solution, entails using a different compressor that is sized to better match the required system load.
Therefore, the correct answer would be d) All of the above. Activities such as doing compression work can add energy to a system, which relates to the functioning of compressors in HVAC systems.
Variable Speed Drive (VSD) or Variable Frequency Drive (VFD):
Utilize a VSD or VFD to control the speed of the compressor motor. This allows for precise modulation of the compressor capacity according to the system's demand.
Multiple Compressors:
Use multiple compressors with different capacities. Staging or cycling these compressors on and off based on the load helps match the capacity to the required demand.