NY-14-004 -- Investigation of Two-Phase Flow in Refrigeration Systems PDF

This paper investigates the performance of evaporator and condenser heat exchangers with respect to pressure drops. This project includes the design of two refrigeration circuits, DX (direct expansion) and flooded, with a common condenser, and analyzes the pressure drop for the heat exchangers and their impact on the overall circuit performance. Several pressure drop correlations and calculation methods are considered and compared with the actual results. The performance of the two circuits is compared for four operating temperatures: -20°C (-4°F), -10°C (14°F), 0°C (32°F), and 5°C (4°F) and analyzed to ascertain suitable pressure dropmethodologyassessmentand circuit operation.DXevaporators are often utilized operating at -10°C(14°F) and below for relatively small duty systems, below 25kW(7.1TR).However, flooded evaporators are rarely seen for systems in this range. The performance of the DX and flooded evaporators is also analyzed for small duties at the four operating conditions.