Assessment and parametric analysis of solar trigeneration system integrating photovoltaic thermal collectors with thermal energy storage under time-of-use electricity pricing

The solar trigeneration system based on coupling photovoltaic thermal (PVT) collectors with an absorption-subcooled compression hybrid cooling configuration has the potential for enhancing solar energy utilization in buildings. Considering time-of-use electricity pricing, the availability of solar cooling often does not coincide with on-peak periods during which electricity prices are high. To benefit from time-of-use pricing for greater economic profitability, sensible heat thermal storage is potential options. However, changeable storage tank temperature affects not only solar cooling capacity but also the electrical output of PVT collectors. Thus, in this work, three operation schemes (i.e., a conventional scheme, heat energy storage and cool energy storage schemes) are compared, and the effect of key design parameters on system performance is analyzed. Models for different system layouts and a conventional photovoltaic (PV-only) system are developed by programming with MATLAB. Annual (8760-hour) simulations are performed based on a case study for a high-rise hotel in sub-tropical cities. The results for Guangzhou show that the system layout, integrating cool energy storage and glazed PVT collectors with low-emissivity coatings, achieves the highest total electricity cost saving, which is 16% higher than that of the PV-only system. Its total solar energy utilization efficiency is 0.321, which is 2.4 times that of the PV-only system. The novelty of this work is that it provides an appropriate energy storage strategy and the design guidelines of key parameters for PVT-based solar trigeneration systems. This work is helpful for PVT-based solar trigeneration systems to improve operating cost savings under time-of-use electricity pricing.