The development of a thermal storage system for a solar driven aqua ammonia heat pump

Abstract

The development of a thermal heat storage system for a solar driven aqua ammonia heat pump is of significant importance to make a truly effective alternative power refrigeration system. This dissertation includes a preliminary design for the specific application as well as verification of the suitability of the design choices made. Literature gives a vast array of methods and materials that can be used for thermal heat storage. Packed beds normally store thermal energy that is provided by solar air heaters. However, this design included a packed bed storage system that uses a water glycol mixture as the heat transfer fluid. After constructing a test bed, multiple runs were completed, using water as the heat transfer fluid, to test the effectiveness of this unconventional method. Amongst others, the project involved determining the pressure drop across the system, the density of the storage material and the void fraction of the packing method. The results showed that the effectiveness of this design was 76.5 % under ideal circumstances. This compares well to other thermal energy storages systems. In conclusion, the study showed that a packed bed storage system using a water glycol mixture as heat transfer fluid is a viable thermal heat storage solution. The project recommendations suggested that the further research can be conducted regarding the shape of the storage material to reduce cost and the void fraction in the system.