Conference Paper Session 16: Presentation 3: Oil Retention in Suction and Discharge Pipes of Vapor Compression Cycles with Various Refrigerants and Oil Types (TA-23-C088)
Oil Retention in Suction and Discharge Pipes of Vapor Compression Cycles with Various Refrigerants and Oil Types (TA-23-C088)
Presenting Author: Haotian Liu, Ph.D., Purdue University, W Lafayette, IN, USA
Author: Eckhard Groll, PhD, Purdue University - Ray W. Herrick Laboratories, West Lafayette, IN, USA
Author: James Braun, Ph.D., Purdue University - Ray W. Herrick Laboratories, West Lafayette, IN, USA
Lubricants are widely used to reduce friction in bearings and other contact surfaces for compressors in vapor compression heat pumping, air conditioning and refrigeration systems. The lubricant also serves as a sealant to reduce leakage and helps in reducing the compression discharge temperature by cooling the compression process. Most systems are designed so that the lubricant that enters the compression chamber is discharged and circulates throughout the system. Depending on the system design and flow rates, significant lubricant can be retained in the compressor suction and discharge vapor line that can lead to reduced efficiency and reliability. Thus, it is important to understand the relationship between oil retention and operating conditions. In this paper, the oil retention is experimentally investigated under various operating conditions with a wide combination of refrigerants (R410A, R32, R1234ze, and R452A) with two different POE (polyolester) oils (POE 32 and POE 100). A test apparatus was designed and constructed to measure the oil retention in both discharge and suction lines with controlled saturation temperature, superheat, refrigerant mass flux, and oil circulation ratio (OCR). The influence of operating conditions as well as the oil type on oil retention is studied to better understand the oil management in vapor compression cycles and provide guidance to system designers.
Learning Objectives:
• Learn the oil retention test stand design and testing procedure in HVAC gas lines..
• Learn the basic modeling techniques of oil retention in HVAC gas lines.