EPA Section 608 Universal Certification ExamType III (Low-Pressure Appliances)Medium
A technician is performing a vapor recovery from a low-pressure chiller. What is the primary method used to maximize the efficiency of vapor recovery from the chiller?
- APressurizing the chiller with nitrogen to push out the vapor.
- BHeating the recovery cylinder to increase its internal pressure.
- CChilling the recovery cylinder to a significantly lower temperature than the chiller.
- DIncreasing the flow rate of the recovery unit's compressor.
Show answer & explanationAnswer & explanation
Correct answer: C. Chilling the recovery cylinder to a significantly lower temperature than the chiller.
To recover vapor efficiently, the recovery cylinder must be colder than the chiller. This creates a pressure differential, causing refrigerant vapor to move from the higher pressure (warmer chiller) to the lower pressure (colder cylinder).
Why the other options are wrong
- A. Pressurizing the chiller with nitrogen would contaminate the refrigerant and is not a standard method for efficient vapor recovery.
- B. Heating the recovery cylinder would increase its pressure, hindering vapor recovery from the chiller, not helping it.
- D. While flow rate is important, the pressure differential created by temperature differences is the primary driver for efficient vapor transfer during vapor recovery from a low-pressure system.
Vapor Recovery Efficiency (Low-Pressure)
To maximize vapor recovery efficiency from a low-pressure chiller, the recovery cylinder should be significantly colder than the chiller to create a pressure differential.
- Colder cylinder creates lower pressure.
- Refrigerant flows from higher to lower pressure.
- Applies to vapor phase recovery.
- Can involve chilling the cylinder or warming the chiller.
Memory trick: Vapor likes to 'Chill Out' in the coldest spot.