Demand response with PCM-based pipe-embedded wall in commercial buildings: Combined passive and active energy storage in envelopes

Demand response (DR) allows Heating Ventilation and Air Conditioning (HVAC) systems to reduce or shift their electricity consumption during peak periods through the global temperature adjustment strategy. Phase change materials (PCM) based walls are the effective energy storage facilities, storing energy in the pre-cooling period and releasing energy during DR event. However, the traditional configuration of PCM-based wall only allows the passive heat transfer between the walls and the indoor air, requiring a long time to complete the phase change process in the pre-cooling period. This paper presents a novel application of PCM-based pipe-embedded wall (PCM-based PE-wall) in building demand response, which combining active and passive heat transfer mechanism to enhance energy storage rates. The effect of PCM-based PE-walls on demand response is evaluated under two different pre-cooling modes: active pre-cooling only (Envelope-2A) and combined passive and active pre-cooling (Envelope-2B). The results show that the implementation of the PCM-based PE-wall can significantly enhance the overall heat transfer rate of the cooling storage in envelopes and thus improving the demand response performance. Compared to traditional PCM walls (Envelope-1), PCM-based PE-walls (Envelope-2B) could cause additional peak demand reductions of 15.78 % and additional energy reductions of 10.18 % during DR events.