Demand side management analysis of a commercial water loop heat pump system

Abstract

Demand side management (DSM) strategies can be used to reduce customers' demand at peak times, change the timing of end-use consumption from high to low-cost periods and increase consumption during off-peak periods. They can be implemented by using the energy flexibility available in the final users' applications, energy storages or control systems to turn on/off end-users' devices when required. Being intensive energy consumers because of a high electric energy demand (refrigeration accounts for about 40 % of the yearly energy consumption), supermarkets are ideal candidates for a DSM approach. This work shows the results of a DSM analysis carried out for a refrigeration and HVAC plant in a supermarket coupled with a Water Loop Heat Pump (WLHP) system. The water loop is used as a heat source/sink for the refrigeration unit supplying the cooling capacity required by food preservation, and for several heat pumps, which provide heating/cooling inside the supermarket building. The system is modelled in TRNSYS and the role of the water loop and its thermal inertia to provide energy flexibility is investigated. The system design and control strategy are modified in order to reduce the electricity costs in presence of demand response programs based on real-time price mechanisms.