Simulated Use Performance of an Integrated Energy System for Thermal and Power Management with Micro-combined Heat and Power in Nano-grid Environments

Integrated energy systems (IESs) are an emerging approach to maximize efficiency and resilience for residential and commercial air conditioning and water heating loads using gas-fired, electrically-driven and/or renewable off-the-self components with distributed energy resources ( DER) and energy storage. IESs include a myriad of equipment combinations, such as furnaces, water heaters and air-source heat pumps (ASHPs), on-site power from micro combined heat and power (mCHP) and solar photovoltaics (PV), as well as electrical and thermal energy storage. When properly integrated and controlled, IESs can serve to balance energy grid supply and demand while exploiting multiple energy sources in ways that improve overall operating cost and efficiencies, minimize emission levels, and provide resilient systems in the built environment. This paper describes an IES developed for residential cold-climate low-load homes driven by customized controls developed by GTI Energy to manage thermal and power generation and storage of a mCHP in a nano-grid environment for space and water heating loads. The IES included an ASHP, hydronic air handler unit (AHU), buffer tank and gas-fired tankless water heater (TWH) powered by mCHP and PV reducing grid power demand. GTI Energy used its Virtual Test Home (VTH) test platform, which applies simulated-use loads to the IES in a dynamic interaction between building energy models and test rigs. The IES was evaluated with real-time weather and corresponding simulated loads using different nano-grid configurations during the heating and cooling seasons. The nano-grids were developed such that power and thermal outputs from the mCHP reduced operating cost and GHGs relative to traditional HVAC solutions. Daily performance results for the IES from the VTH evaluations are presented to demonstrate the pros and cons of each nano-grid configuration. This paper includes a modeled comparison of the IES operating cost and emissions levels relative to commercially available advanced all-electric and fuel-fired systems for residential space and water heating applications.