Integration of a solar power plant and a heat pump into a hot water supply system based on a digital twin

Abstract

In the context of growing threats to Ukraine’s energy security and the need to increase the autonomy of the residential sector, the study of the effective combination of heat pumps and solar generation is highly relevant. The aim of the study was to justify the feasibility of integrating an air-to-water heat pump into the hot water supply system of an multi-apartment building equipped with a solar power plant, using a digital twin to improve energy efficiency and autonomy. The following methods were used in the study: analysis of the actual energy consumption database, energy modelling in the PV*SOL programme, instrumental monitoring of temperatures, water and electricity consumption, as well as comparison of system configuration options taking into account seasonal characteristics. A comparison of heat pump operating modes was carried out: full heating (up to 55°C) and bivalent (up to 35°C with reheating). Seasonal efficiency, coverage of needs from the solar power plant and system balancing options were calculated. As a result, it was found that the actual hot water consumption is 21.5 times lower than the standard, and more than 60% of the thermal energy is spent on circulation. Excess generation by the solar array (over 16,000 kWh/year) can be effectively used to heat water through a heat pump. In the heating mode up to 35°C, electricity consumption is reduced by 50.9% compared to the full water heating mode (up to 55°C). The study also proposed a digital twin of a hybrid solar power plant-heat pump system that adapts to changes in load and operating conditions. For the first time, a quantitative assessment of the efficiency of the bivalent mode in real-life conditions has been carried out, taking into account actual consumption. The results can be used for adaptive design of hot water supply systems in residential buildings. The proposed approach allows reducing costs, increasing autonomy, reducing the load on the network, and adapting systems to crisis conditions and changes in consumer behaviour