Designing a PCM storage system using the effectiveness-number of transfer units method in low energy cooling of buildings

摘要

An investigation into characterising and optimising the useful latent energy that can be stored within a tube-in-tank phase change thermal energy storage system has been conducted, with particular reference to off peak thermal storage applications for cooling buildings. This process involved determining the actual useful energy that can be stored within a phase change material (PCM) storage system coupled to a low energy night time cooling system using a cooling tower. The useful energy that can be stored within the PCM was determined using a validated effectivess-NTU model. The energy storage effectiveness of the PCM system was determined, which directly indicates how much of the PCM was useful. This storage effectiveness was optimised delivering a storage effectiveness of 68% and 75%. This parameter can be directly compared to sensible storage systems and it was found that tube-in-tank systems can store more than 18 times more useful energy than sensible storage systems per unit volume.