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Cost reduction of heat pump water heating in cold climates for low to moderate income families.

Number: 3437

Author(s) : MALHOTRA M., KRISHNAN E., RENDALL J., CASEY F., LI Y., NAWAZ K., SUN J., BRECHTL J., WOREK W., KLEIN G.

Summary

Heat pump water heaters (HPWHs) are much more efficient than natural gas burner or electric resistance water heaters but have poor performance at low ambient air temperatures. In multifamily residences, unitary air-source (AS) HPWHs installed in small mechanical closets draw usable heat from indoor space, resulting in higher space heating loads in winter, especially in cold climates where water heating loads are typically higher than in warm climates. In multifamily buildings served by centralized HPWH systems, AS-HPWHs require make-up air from the outdoors, significantly impacting their capacity and energy performance in colder months. Therefore, incentivizing AS-HPWHs that draw heat from indoor space or require substantial amounts of outdoor air may not alleviate the energy burden for low-income households in cold climates. To address these challenges, a novel system has been proposed that integrates centralized water-source (WS) HPWH with drain water heat recovery (DWHR) to utilize warm temperature drain water as the heat source, and small tanks distributed to each apartment to reduce heat loss in the centralized hotwater recirculation loop. The modeled performance of this hybrid Centralized & Distributed (C&D) drain-source (DS) HPWH system in cold climate yielded a yearly coefficient of performance (COP) exceeding 4.0. This paper provides a concise summary of modeling and presents a technoeconomic analysis, comparing the life cycle costs of proposed DS-HPWH system in centralized and C&D configurations with central AS-HPWH and traditional water heating solutions including unitary electric resistance, unitary HPWH and central natural gas water heating system. Besides the installation and maintenance costs, the analysis accounts for the financial incentives available to low-income households offered through IRA (Inflation Reduction Act). The results demonstrate that the proposed DS-HPWH technology is cost competitive compared to all other analyzed water heating technologies.

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Pages: 10 p.

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Details

  • Original title: Cost reduction of heat pump water heating in cold climates for low to moderate income families.
  • Record ID : 30032932
  • Languages: English
  • Source: 2024 Purdue Conferences. 8th International High Performance Buildings Conference at Purdue.
  • Publication date: 2024/07/15

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