Thermal storage (TES) reduces the overall load from the nexushaus to minimize consumption during high electricity price hours, and maximize the utility of the house’s solar electricity production.
The built environment (residential and commercial buildings) is responsible for approximately 40% of the energy consumption and 48% of the water use (11% directly, and 37% indirectly through thermoelectric power generation) in the United States. Therefore, focusing on the built environment and residential houses in particular, provides an opportunity for cross-cutting efficiency by including integrated energy, water, and food production systems.
Addressing Electricity Grid Issues with Integrated Energy-Water Systems
The intent of the design approach is to ensure both the viability and compatibility of the house’s integration into the existing infrastructure of the neighborhood. UT and TUM are developing integrated water and energy systems, so that the house will not overwhelm the stressed utility distribution infrastructure with their additional demand (e.g. electricity, water, and waste water), and instead, will utilize these resources in the most effective ways possible.
Specifically related to energy, nexushaus incorporates two symbiotic strategies. First, the house is outfitted with a 7kW solar array that can easily interface with the existing transmission infrastructure and produces more electricity than the house consumes. This surplus creates electrons that are locally available to the immediate, surrounding neighborhood. In addition, a hydronic HVAC system, coupled with a thermal energy storage (TES) system, allows nexushaus to employ a peak-shifting strategy that reduces electricity consumption on peak—between 2PM and 8PM—by approximately 80% (Shown in the Graph).
This system, coupled with solar, generates maximum electricity on peak, while simultaneously reducing the house load. The goal is not just to minimize air conditioning load on the grid, but to also provide as much excess energy as possible to support the surrounding neighborhood when power is needed most. This approach benefits other grid-connected stakeholders, and will save the home occupant significantly on their utility bills in areas where there is real-time.