Design and analysisof evaporator with spiral mini channel

In this study, an evaporator as a heat exchanger was designed by combining discs with spiral mini channels in the shall and its thermal analysis was carried out. The designed heat exchanger is named as Spiral Mini Channel Evaporator (SMKE). The mini-channels on the disc are designed as single-input and three-input. There are five spiral-channel discs inside the shall. Because of the mini channels on both surfaces of the discs, the refrigerant can double pass on the disc. The flow between the discs is provided by the union connectors placed at the inlets and outlets of the mini channels. Single and three pass flow conditions on the disc were compared in terms of thermal performance. Water in the shall and R134a in the mini-channel was chosen as the working fluid. Operating pressure in the heat exchanger is adjusted as 4, 4.5 and 5 bar. the refrigerant temperatures at inlet to the heat exchanger are fixed as values of 0°C, -3°C and -6°C. Also, the experiments were carried out at three different mass fluxes (150 kg/m²s, 200 kg/m²s and 250 kg/m²s). The water temperatures at inlet to the shall side varied in the range of 10.5-11.5°C. According to the data obtained; with increasing the number of spiral entries on the disk, the efficiency of the heat exchanger increases. Increasing the number of mini-channel inlets causes flow to occur at the same flow rate but at a lower fluid velocity. Finally, this case results in an increase in heat transfer.