Numerical investigation of solar thermal heat storage potential under UK climatic conditions

In this study a well-insulated 100 m² home in the UK was considered. The daily and seasonal heat load of the building was calculated and found to be 4.21 kW (October) and 6.22 kW (January). Analysis of the amount of seasonal storable energy generated in the spring and summer period’s shows that there is ≈8780 kWh available whereas the total building heat load for one year is 10517.5 kWh. This demonstrates that the amount of storable solar energy wields ≈ 92% of the yearly heat load of a well-insulated UK house. To maximise the use of solar energy (and help provide this 92%) a review of the most promising heat storage methods and materials was undertaken to determine the best option for both long and short term periods. Thermochemical storage materials such as CaCl2, zeolites and silica gels were found to have the highest storage potential coupled with low space requirement due to their high energy density. For storage of inter-seasonal collected energy, this would require ≈ 50 → 77 m³ of these materials whereas the amount of paraffin (latent) or rock (sensible) required to provide the same levels of heat storage would be 90 and 392 m³ respectively.