Active heat storage characteristics of active-passive triple wall with phase change material

In passive solar greenhouses, the solar energy obtained by the wall cannot be used efficiently for heating the indoor environment, due to a thermal-stable layer inside the wall, which is caused by the limitation in heat transfer properties of building materials. In order to solve this problem, a new system combining an active passive triple phase change material wall (APTPCMW) and solar concentrators is proposed and introduced in this paper. To investigate the active heat storage performance of APTPCMW, an experiment is designed and carried out. From the experiment, the significant contribution of the new proposed system to improving the heat storage capacity of the middle layer of APTPCMW has been confirmed. Additionally, factors, namely, the gap between air tunnels, the flow direction of heated air, the temperature and velocity of the supply air, have been identified to have influence on the active heat storage performance of APTPCMW. For real applications, optimum operational conditions of APTPCMW have also been identified from the experiment. (C) 2014 Elsevier Ltd. All rights reserved.