The Role of Hybrid Energy Modules for improving building efficiency in the future electric grid

The Hybrid Energy Module (HEM) is a promising configuration for a distributed energy resource (DER) that combines both thermal and electrical energy storage with a micro-source that is capable of producing a significant amount of heat in addition to electricity (e.g., fuel cells, natural gas gen-set). The availability of the energy storage components makes it possible to utilize a larger fraction of the heat and electricity generated by the micro-source during Combined Heating and Power (CHP) operation in buildings. However, the amount of energy storage required to deliver the desired building efficiency benefits and the resulting installation costs are heavily dependent on the building type, its location, and the time of year. This study employs linear programming to identify the optimum component ratings and dispatch schedules, and calculates the resulting building efficiency benefits and installation costs. Preliminary results from these optimization case studies deliver promising results suggesting that the HEM configuration is capable of providing significant efficiency advantages in apartment and office buildings located in the northern climate zones of the continental U.S. A dynamic model that is appropriate for analysis of the HEM´s fast transient response is developed for the studied HEM configuration using a natural gas gen-set, and experimental results confirm its usefulness.