Cooling performance and energy saving of a refrigeration cavity supported by an outside cold air flow controlled by a PID controller

This paper aims to prove the efficiency of using the free, abundant cold air flow stemming from the outside in high altitude to enhance the cooling inside a refrigeration cavity and to reduce the energy consumption. The cold air flow is spread out inside a cavity covering the side wall of the appliance and, which is connected to the inlet and outlet conducts. For that purpose, a Simulink model is proposed to model this installation. The internal temperature is computed according to the evaporator temperature and the outside cold air flow, which is also computed according to the outside temperature. The simulation results show that when the internal temperature is higher than the desired one and the outside temperature is low enough, the use of the controlled cold air flow as a second cooling source allowed to speed-up the cooling inside the refrigeration cavity of about 36.21 % and to reach an energy saving of about 36.23% compared with the classical thermostatic control. When the internal temperature drops below the desired one, the appliance did not consume any energy.