Graduation Date

Spring 2020

Document Type



Master of Science degree with a major in Environmental Systems, option Environmental Resources Engineering

Committee Chair Name

Peter Alstone

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Arne Jacobson

Second Committee Member Affiliation

HSU Faculty or Staff

Subject Categories

Environmental Resources Engineering


Water heating in residential buildings, also known as domestic hot water (DHW), is the third largest use of energy after appliances and space conditioning. About 90% of the residential buildings in the state use natural gas fueled water heaters, 6% use electricity, and a small percent use liquefied petroleum gas (LPG) or solar water heaters. The current energy use associated with residential water heating is small relative to the total amount of energy consumption in the residential building sector, but it is still a contributor of greenhouse gas (GHG) emissions. Improving hot water systems can be beneficial for bill customer savings, energy use, and water savings.

Heat pump water heaters (HPWH) can function as grid batteries by using the water tank capability of thermal storage. The use of aggregated electrical DHW systems to store extra electricity during peak generation times or during low utility time of use (TOU) rates has the potential to alleviate some of the curtailed renewable energy power generation sources in the California grid while reducing carbon emissions and customer cost.

Water heating technology was simulated using the Building Energy Modeling software California Building Energy for Code Compliance (CBECC-Res) and the California Simulation Engine (CSE). Different climate zones were explored to compare the electricity needed for a water heater operation given the same input parameters of water draw profiles and building envelope. The results show the feasibility of using HPWH and ERWH technology to participate in demand response management programs. The demand response capability of HPWH and ERWH show that they could be useful tools to accommodate surplus energy from solar generation during the solar peak hours. Whether the demand response is implemented using traditional HPWH or ERWH units, the capability of the technology to act on control signals is a necessary condition for a successful program.

Citation Style



Thesis/Project Location