Numerical analysis of a combined heat pump ice energy storage system without solar benefit-Analytical validation and comparison with long term experimental data over one year

Ice energy storage systems, as interface between the time-shifted occurring heat and cold demand of nonresidential buildings, are a promising technology to use waste heat arising inside buildings. Several studies examine the suitability for residential buildings in combination with solar thermal power. However, investigations of ice energy storage systems for nonresidential buildings to use waste heat instead of solar benefit are missing. In order to design, evaluate and optimize such systems, analysis of its behavior by means of variational calculations are essential, which requires an adaptable model that is thoroughly validated. Therefore, for the first time, a detailed numerical model of such a system is developed, validated and compared to long term measured data of a 500 m3 setup. The storage at the University of Bayreuth acts as heat source for a heat pump and is regenerated by the cooling water network delivering the waste heat, which can also be used as a direct source for the heat pump. The Stefan problem is utilized to conduct the validation and, moreover, a comparison with 13 months of measured data shows good agreement. In the future, the model will be used to identify favorable procedures for implementing, optimizing and controlling ice energy storage systems in nonresidential buildings with waste heat recovery capability.

Automated summary

Ice energy storage systems have the potential to be a promising technology for utilizing waste heat in nonresidential buildings. However, there is a lack of research on using waste heat instead of solar benefit in these systems. This study develops a detailed numerical model and validates it with measured data, aiming to optimize and control ice energy storage systems in nonresidential buildings with waste heat recovery capability.