Computational performance prediction of an adaptable thermal storage concept

In the Netherlands and in other moderate climates, residential buildings with low thermal mass (e.g. steel frame constructions) demand less heating energy during intermittent use compared to high thermal mass buildings; this is caused by a shorter pre-heating period. Although low thermal mass buildings are sensitive to overheating, these problems can be alleviated, e.g., with stricter blind control strategies or appropriate ventilation strategies. Another solution is to increase the building’s thermal storage capacity. However, the latter will reduce the low thermal mass benefit of a shorter pre-heating period. Therefore, in this paper, we propose a concept with an adaptable storage capacity. The concept combines the benefits of buildings with low and high thermal mass by applying adaptable thermal storage to a lightweight building. The proposed adaptable thermal storage concept consists of phase change materials (PCMs) as thermal storage medium placed above a thermally insulating ceiling. This ceiling can be opened or closed to influence airflow to the PCMs and thus thermally couple or decouple the PCMs from the room. In this paper, we investigate the potential of this concept using computational building performance simulation. To assess the potential, the design of the concept needs to be optimized. Since the performance of the concept strongly depends on its operation, it is necessary to integrate optimal control strategies during the design optimization. A design optimization method which includes model predictive control is discussed in this paper.