Energy modeling development and calibration for a mini district energy loop assessment comprised of a set of campus buildings

Abstract

District energy loops are comprised of a network of buildings connected in a water-source loop with utilization of heat pumps to allow for buildings to share thermal energy. To assess the feasibility of creating a district energy loop, the heat sharing capabilities of the proposed interconnected buildings needs to be analyzed. This paper develops a method to assess a mini-district energy loop from historical utility data. Energy modeling was used to create a simple building model from building construction specifications and given inputs from the University Services Engineers on Montana State University's campus. With the energy model developed, the historical utility data was compared to the hourly heat demand and electricity consumption for the building on an outdoor temperature basis. Calibration techniques for heat demand were comprised of increasing or decreasing the outdoor air ventilation requirement and the base heat demand. Electricity consumption was calibrated by altering the equipment plug load in the spaces. The simulated data was validated with metered hourly heat demand data for a high-energy use laboratory building on MSU's campus. This simple energy model was reconfigured to represent another building at MSU by altering building envelope dimensions, and then re-applying calibration techniques to generate hourly heating and cooling data. Converting the model to be heat-pump compatible allowed for internal thermal energy sharing within the building to occur. Hourly heat demand and hourly heat availability were determined for external thermal energy sharing for a high-energy use laboratory building. After which, heat sources, heat sinks, and thermal energy storage tanks were assessed to determine the feasibility of a district energy loop.