Dynamic modelling and analysis of a novel latent heat battery in tankless domestic solar water heating

The concept of integrating latent heat with domestic solar water heater (DSWH) has been around for few decades but commercial application has not been recognized yet. This might be due to the lack of feasibility studies for latent heat technology particularly for long-term operation. In this paper, we developed a process flowsheet that integrates a latent heat 'battery' (LHB) into a domestic solar water heater (LHB-DSWH) eliminating the traditional water tank. In this novel tankless LHB-DSWH, the hot water does not need to be continuously maintained at health-regulation-constraint temperature (viz. 60 °C to prevent the breeding of Legionella bacteria) as in the case of conventional DSWH or other literature LHB-DSWH processes. A dynamic model of the proposed LHB-DSWH process was developed and validated against experimental data. The dynamic characteristics for the proposed system were examined and discussed. An annual simulation for a case-study (Townsville, QLD Australia) showed that the proposed LHB process consumes 86.6% less fossil-fuel compared to a conventional system and increases the fossil fuel savings of DSWH from 81.7% up to 97.4%. Process operability was also considered in the process development.