Application Potential of a Hybrid Ground Source Heat Pump Array for the UC Berkeley Campus Business and Law Node Energy System: A Preliminary Study

The current plan divides the UC Berkeley (UCB) campus energy system into five nodes, where the Business and Law node was studied because of an open field site for borehole installation. The Pacific Northwest National Laboratory's Commercial Prototype Building Models were used to estimate heating and cooling load requirements for UCB campus building types by considering model characteristics (for example, high base load from hospitals, high DHW in hotels) corresponding to the ASHRAE Standard 90.1-2013. Unscaled load profiles were created from the EnergyPlus building energy simulation and scaled with monitored peak load and annual energy use to generate the target node's hourly heating and cooling load profiles. An optimization problem was solved to design a hybrid GSHP system, where the objective function is the lifetime total cost of the system, and the optimization variables are the portion of heating and cooling loads covered by the GSHP system. Modelica models for air source and ground source heat pump systems were built for detailed case studies based on optimization results. In the Modelica model, the demand side is connected to the radiators in the building to transfer heat, and the source side is connected to GSHP, ASHP, or other heating and cooling facilities. The results demonstrate that an appropriate hybrid GSHP system can help reduce both borehole numbers and electricity consumption for the UCB campus site.