Sorption thermal energy storage: Hybrid coating/granules adsorber design and hybrid TCM/PCM operation

A novel adsorber design combining fin-coating and filling of granules between the fins is introduced for closed sorption thermal energy storage. A storage system is designed and assembled, experimental results are presented for charging and discharging, heating and cooling. Considering the use case of the thermal management of the battery in a hybrid vehicle, a total cooling energy of 544(8) Wh in a period of 30 min is measured, which gives an average cooling power of 1.05(8) kW. A novel hybrid operation mode is proposed for discharging the storage for heating purposes, exploiting the features of both phase-change and thermochemical materials simultaneously by allowing water to freeze in the evaporator. The freezing enthalpy can then be exploited as evaporation enthalpy, removing the need for an external low-temperature heat source for the evaporator. This hybrid operation might be beneficial, e.g. in winter in order to preheat the battery before discharging it.