Residential peak demand management of space cooling systems through thermal storage and rooftop PV in Brisbane

This paper studies the potential benefits of implementing distributed thermal energy storage units in residential buildings. Peak demand management of space cooling systems is regarded as an important issue, as the sudden peaks in summer can create electrical network instabilities, and possibly state-wide blackout as well as very high electricity spot prices. Current instantaneous airconditioning (AC) systems in the built environment are not able to store thermal energy and shift the cooling demand of buildings, which is one of the main reasons causing sudden peaks in summer. In this research, a range of evaluation and quantitative analysis have been performed for a real 5-star (Nationwide House Energy Rating Scheme) house in Brisbane. The results show that the space cooling system with cold storage, powered by a 5.0-kW solar PV system results in a reduction of 79% in its summer grid-electricity demand. The peak hourly cooling load was also observed to shift and reduce by 47%. In comparison, the PV size is reduced to 2.8 kW, the summer grid consumption and peak demand reductions decline by 60% and 22% respectively. This decline is due to the lower hourly output power of the smaller PV system. However, in terms of PV self-consumption, the 2.8-kW system obtains higher improvement by employing a thermal storage system. The study demonstrated that adding thermal storage systems in residential houses can effectively manage space cooling demand, reduce peak cooling load, and shift the peak load.