Ventilation cooling/heating performance of a PCM enhanced ventilated window - an experimental study

This paper presents a phase change material enhanced ventilated window (PCMVW) for both ventilation pre-cooling and pre-heating purposes. The PCM heat exchanger is used as a heat sink in the ventilation pre-cooling application and thermal energy storage in the ventilation pre-heating application. The paper presents a night cooling experiment and a solar energy storage experiment in order to investigate the thermal and energy performance of the PCMVW, and a ventilated window (VW) self-cooling experiment for overheating protection. Two VWs were tested in the façade lab in Aalborg (Denmark), and one of them is with PCM heat exchanger. The two windows were equipped with the same outdoor conditions and ventilation airflow. The experimental results show that for ventilation pre-cooling application with the PCM heat exchanger, the room inlet air temperature is by average 1.4 °C lower for 7 h during the daytime compared to the normal VW. The average energy saving is 0.7 MJ/day compared to a normal VW. The PCMVW cooling capacity is limited without advanced blinds control and system operation control. In ventilation pre-heating application, the PCM increases the inlet air temperature of the VW by 2.0 °C for 12 h. The average energy saving is 1.6 MJ/day compared to a normal VW. Buildings in a climate with high outdoor air temperature differences can benefit more from the PCMVW in ventilation pre-cooling application, but the pre-cooling ability is limited. While in ventilation pre-heating application the buildings in the climate with higher solar radiation levels has a higher energy performance. Moreover, the VW self-cooling application is more effective to decrease the overheating of the room than VW without self-cooling.