Free convection on a refrigerator’s condenser

Abstract

The paper presents the measurement of heat transfer coefficient for the refrigerator’s condenser in free convection regime. The water was pumped through the steel coils of heat exchanger with a constant flow rate and its temperature was kept at a demanded value by means of ultrathermostat. The research was conducted in stationary conditions which were controlled by a continuous measurement of the water temperature at inflow and outflow to the heat exchanger. The temperature distribution at the external condenser surface was registered by means of an infrared camera. Single elements used to the analysis were selected using the thermogram registered. In free convection regime and in case of small temperature change the heat transfer coefficient value can be calculated by comparing the measured temperature area with analytical solution describing one-dimensional temperature distribution along the rib. The accuracy of the proposed method for measuring the heat transfer coefficient was examined by comparing the heat transferred to the air and the heat lost by water flowing through the spiral of heat exchanger. An error between these two parameters is about 6%.