Numerical investigation of an evacuated tube solar collector in a solar assisted rooftop unit

Abstract

In this study, numerical analysis of an evacuated tube solar collector integrated into the discharge line in a rooftop air conditioner is carried out. The goal in this system is to increase the efficiency of the unit by reducing the compressor energy consumption with the solar collector. The solar collector consists of vacuum tube collectors. Inside the vacuum tube, there is a copper pipe installation through which the R410a refrigerant in the superheated vapor phase, which is compressed by the compressor, passes. The remaining volume from the copper pipes in the tube is filled with a heat transfer fluid to increase the collector efficiency. In this study, the type of heat transfer fluid filled to the collector for the operating condition of the unit in summer and winter conditions are investigated parametrically and numerically. With the findings obtained, the surface temperature of the copper pipe installation in the collector in the compressor discharge line, depending on the type of heat transfer fluid, is presented comparatively.