Investigation of Liquid Overfeed and DX Refrigeration Systems Performance

摘要

This paper investigates the performance of liquid overfeed and direct-expansion (DX) refrigeration systems and includes component performance and system balance. This project includes the design of two refrigeration circuits, liquid overfeed flooded and DX with a common condenser, and analyzes the performance of the heat exchangers and their impact on the overall circuit's performance. Several design techniques and methods are considered, including geometry and construction of heat exchangers. The performance of the two circuits is compared for four operating temperatures; -20℃ (-4℉), -10℃ (14℉), 0℃ (32℉), and 5℃ (4℉); and analyzed to ascertain circuit operation. DX evaporators are often utilized operatingat-10℃ (14℉) and belowfor relatively small duty systems, below 25 kW (7.1 TR). However, liquid overfeed flooded evaporators are rarely seen practically for systems in this range. The performance of the DX and liquid overfeed flooded evaporators is also analyzed for small duties at the four operating conditions.