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Analysis and design of a drain water heat recovery storage unit based on PCM plates

Morales-Ruiz, S., Rigola, J., Oliet, C., Oliva, A.
Applied energy 2016 v.179 pp. 1006-1019
drainage water, energy, experimental design, heat transfer, mathematical models, thermal properties, water flow
This paper is focused on the detailed analysis of a PCM plate heat storage unit with a particular configuration, looking for the maximum contact area with the fluid (water) and the minimum volume to be used in a real household application. In that sense, a numerical study of the thermal and fluid dynamic behaviour of the water flow and the PCM melting-solidification processes, together with the thermal behaviour of the solid elements of the unit, has been carried out. On the other hand, an experimental set-up has been designed and built to validate the numerical model and characterise the performance of the heat storage unit. The purpose of the numerical and experimental study is to present a series of results to describe the heat storage unit performance in function of the time. Thus, after a preliminary design study three different cases have been simulated and tested. A 7.2%of discrepancy between numerical results and experimental data has been evaluated for the heat transfer. The PCM heat storage unit designed is capable to store approx. 75%of the thermal energy from the previous process wasted water heat, and recover part of it to supply around 50%of the thermal energy required to heat up the next process.