Performance evaluation of solar-assisted air-conditioning system with chilled water storage (CIESOL building)

► We present a new solar-assisted air-conditioning system’s operation sequence. ► This mode considers the chilled water tanks action with variable-speed pump. ► It permits to save about 20% and 30% of energy and water consumption, respectively. ► It allows storing the excess cooling capacity of the absorption chiller. ► It prevents the sudden start/stop (on/off cycles) of the absorption chiller. This study presents the performance of solar-assisted air-conditioning system with two chilled water storage tanks installed in the Solar Energy Research Center building. The system consists mainly of solar collectors’ array, a hot-water driven absorption chiller, a cooling tower, two hot storage tanks, an auxiliary heater as well as two chilled storage tanks. The chilled water storage tank circuit was further investigated in order to find the optimum solar system’s operation sequence while providing the best energy performance. Firstly, we carried out a study about the dynamics of building’s cooling load and the necessity of the integration of chilled water storage tanks to solar system. Subsequently, the new system’s operation mode was proposed to reduce the energy consumption. The results demonstrate that we can save about 20% of the total energy consumption and about 30% of water consumption applying the new operation sequence, which takes into account the chilled water tanks action. Moreover, it was demonstrated that the integration of chilled water storage tanks allows to reduce the sudden absorption chiller on/off cycles, thereby improving the efficiency of the solar-assisted system.