Analysis of a photovoltaic-thermal collector-based energy system for powering multi-unit residential buildings

Multi-unit residential buildings represent an emerging archetype that requires energy for cooling, heating, and power typically supplied from the local grid. Renewable energy-based solutions meet this energy demand in a sustainable manner by reducing pressure on existing grid infrastructure. In this study, a transient numerical model of a building-based photovoltaic/thermal driven combined cooling, heating and power system with two latent heat thermal energy storage tanks is developed in TRNSYS and C++. The proposed system is assessed for its capability to offset the electrical, space conditioning and domestic hot water requirements of a low-energy multi-unit residential building comprising 12 individual units. This combination demonstrates a novel integration between the proposed system and emerging residential building archetype in North America. A parametric analysis is conducted in which four annual simulations are conducted. Two North American case study locations representing a heating dominated (Ottawa, Canada) and a cooling dominated (Albuquerque, United States of America) climate are examined. For each location, two scenarios of solar collector array area are considered. System performance is assessed via calculation of the annual solar fraction, electricity fraction, and grid electricity consumption. Results show that the total grid electricity consumption varies between 373.6 GJ and 427.5 GJ depending on the local climate conditions, and also operating the system in Albuquerque relative to Ottawa results in an increase in solar fraction and electricity fraction of up to 62% and 40%, respectively. However, increasing the solar collector array area in Ottawa corresponds to an increase in solar fraction, whereas in Albuquerque the solar fraction remains relatively constant, highlighting the proposed system's sensitivity to the local climate. • A novel dual tank control algorithm is integrated into a low energy residential building. • The low energy multi-unit residential building consists of 12 units. • The climate location and collector area are varied in the analysis. • The solar and electricity fractions, and grid electricity consumption are calculated. • The location of the system is an important factor for increasing performance.