Improving the energy flexibility of single-family homes through adjustments to envelope and heat pump parameters

With the increase of fluctuating renewable resources both on the grid and locally on buildings, a need arises for buildings to be flexible such that their energy demand can be modified to match energy generation. This study aims to characterize key approaches to increase the flexibility of a single-family home subject to a number of climate conditions. The home is modeled in TRNSYS in 5 climates, and building thermal mass, heat pump characteristics, and water heating setpoints are adjusted to assess the impact of each on the building's flexibility. The key metric used to assess flexibility is the cumulative absolute residual load over a year, where the residual load is defined as the difference between the average hourly demand of electricity and the average hourly available electricity. A control scheme is employed to implement demand response, but overall energy demand and thermal comfort are also considered throughout the year to assess effectiveness of the demand response approach. Results presented on 21 variations to the base house show the benefit of thermal mass in maintaining thermal comfort while changing thermostat setpoints and demonstrate the benefit of variable speed heat pumps for meeting available electricity supply. In the best case, a 36% decrease in residual load over the year is found for a simulation in Gaithersburg, MD compared to the base case. Results from this work suggest best approaches to take when developing new housing stock if consideration is needed for how well the buildings can respond to fluctuations in energy generation from intermittent sources such as wind and solar.