Using hydrate slurries to increase the solar fraction of solar heating and cooling systems.

The contribution of solar thermal energy to the final energy consumption has significantly increased in recent years. However the use of solar thermal energy to drive sorption heating / cooling systems is still less than 2% of the total installed solar thermal technology capacity. Reason for this low penetration are costs and complexity associated with limited solar fractions. The IEA expects that by 2050 solar thermal energy will have a major share in the CO2 emissions reduction associated with the built environment. Thermal storage can significantly increase the solar fraction of solar driven sorption heating / cooling systems. This paper discusses the aspects that should be considered when selecting the latent heat storage for a specific solar heating and cooling application. It positions latent heat storage in relation to solar heating and cooling systems helping determine the storage temperature level. It quantifies temperature losses and indicates how the major sources of irreversibilities can be quantified. It distinguishes between stationary phase change materials and pumpable slurries of phase change materials and illustrates the advantages of pumpable PCM slurries.