A heuristic algorithm for optimal load splitting in hybrid thermally activated building systems

Abstract

Thermally activated building systems (TABS) integrate high thermal inertia into the heating and cooling system, which has advantages and disadvantages. During sudden fluctuations and high peaks in the energy demand of a building, the thermal comfort may not be efficiently maintained by TABS due to its slow reaction to the control signals. Thus, one solution is to add a complementary fast-reacting emission system to offset the peak loads and guarantee thermal comfort. Conversely, the high thermal inertia of TABS offers peak-shaving and load-shifting opportunities. By optimally exploiting the high thermal inertia of TABS, significant downsizing of the production system can be achieved. Thus, the dynamic behavior of the TABS must be incorporated into the design procedure. Furthermore, the optimal load split between the TABS and the secondary system is a key design consideration. This study reviews the reasons why an appropriate design methodology is not currently available. Moreover, an optimal load splitting algorithm (OLSA) is proposed as a solution, and its performance was verified against a baseline scenario by applying it to nine case studies. The results demonstrate that the OLSA estimated the optimal load split with a maximum error of 9.6%. The application of the OLSA as an easy-to-use tool for the designer was also illustrated. Additionally, the OLSA provided a significant downsizing of the components in the early-stage design (45% in cooling and 38% in heating).