DESIGN ANALYSIS OF A FINNED TUBE HEAT EXCHANGER FOR AN AIR-TO-WATER REVERSIBLE HEAT PUMP WORKING WITH PROPANE (R290) AS REFRIGERANT
The finned tube heat exchanger "coil" is widely used in refrigeration, air conditioners and heat pump applications. In this study, a statistical method together with a simulation model were employed to analyze the effects of several coil geometry factors on the performance (COP) of an air-to-water reversible heat pump in both modes of operation. The main aim of this investigation is to find a coil design that improves the efficiency of a heat pump working with R290 as refrigerant. As a result, it was found that certain relation exists between the number of circuits and tube diameter for which are possible to obtain the maximum COP in heating or cooling mode. In heating mode (coil as the evaporator), the combination of 9 circuits and tube diameter of 8.9 mm gives a maximum COP of 3.74 along with a pressure drop of 25.2kPa. For the coil acting as a condenser in cooling mode, the optimum COP is obtained with 6 circuits and tube ID of 6.5 mm. This design yields a 5% increase in the COP with a reduction of 49% and 27% in the refrigerant volume and total area with regard to the baseline design configuration, respectively.