Cost Compression for Multifamily Heat Pump Water Heaters

The heat pump water heater (HPWH) system design included in this proposal is applicable for multifamily housing units with four or more units. The project team will demonstrate the feasibility of replacing existing water heating technologies in the current building stock with HPWHs. Within the current building stock, the replacement of centralized water heating systems appears to be the most feasible for current and new technologies developed at ORNL. A stretch goal in this project is retrofitting distributed heating to a hybrid centralized/decentralized system. This system design would result in the largest total cost savings and will require the new technologies developed at ORNL. This proposal will investigate and outline the path to a 30% cost reduction (product, installation, and user costs), 25% available hot water increase for the same amount of stored hot water, and up to 1,000x reduction in EOL CO2 emissions for cold climates when compared with current state-of-the-art HPWHs using R134a—all while providing equitable control of the hot water the family receives. The system design will be improved using the guidance of numerical modeling, verification through lab-scale testing, and finally pilot-scale testing to ensure the feasibility of deployment of the cost-reducing methods.

This project has three primary objectives:

• Objective 1: Development of a validated cost model including both equipment (capital and operation) and installation cost to accurately assess the contribution of various components.
• Objective 2: Identification of potential cost reduction elements that can enable a realizable impact on the overall cost of the system. This cost-saving analysis includes critical process controls and various installation configurations to develop a good understanding of contributing factors.
• Objective 3: Conduct a detailed parametric analysis based on major cost elements and develop guidelines for manufacturers, installers, and building operators to achieve reduced cost while ensuring compliance with environmental aspects.

Project Impact

This project enables households to adjust small electric resistance water heaters to their preferred temperature, leading to decreased energy costs for low-income families in cold climates and ensuring consistent hot water supply for all residences equipped with this water heater system.