Experimental investigation and modelling of a low temperature PCM thermal energy exchange and storage system

• We present an experimental pilot of latent heat thermal energy storage device.
• We propose a 1D model of the storage device transferring heat into air during the discharge phase.
• We compare experimental measurements and numerical simulations to validate the model.
• We propose a differential model of a building and connect it with a model of LHTES device.
• The capability of the LHTES model to contribute to design a process (sizing) is qualified.

A real-scale latent heat thermal energy storage (LHTES) device has been designed and set up for air-cooling in the housing sector. This system uses the thermal gap between night-time and daytime outdoor air to refresh the indoor air. The air passes along a box-section horizontal tube bundle filled with paraffin wax (phase change material). To develop a design tool, a one-dimensional model is proposed which describes the thermal behaviour of the LHTES device as the paraffin wax melts. This model takes into account the close-contact exchange between the PCM and the surface of the tubes due to the decreasing density of the PCM as it melts, and the corresponding buoyancy phenomenon. An enthalpy formulation is used for the PCM energy balance equation. An experimental study is performed which validates the modelling approach. This model will be used to simulate the LHTES devices of two single family houses (Napevomo, Sumbiosi). Finally, a first illustrative application of the simulation model of LHTES device is developed by coupling it with a basic mono-zone building performance programme.