A Comprehensive, High Efficiency Solution for Water Heating in Multi-Family Buildings

Integration of solar thermal with gas engine heat pump technology and advanced controls to reduce hot water energy consumption for apartment buildings.

Building Decarbonization

Energx Controls, Inc.

Recipient

Cypress, CA

Recipient Location

36th

Senate District

67th

Assembly District

beenhere

$753,604

Amount Spent

closed

Completed

Project Status

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Project Result

Construction was completed in January 2020. The evacuated tube solar collectors are performing satisfactorily; however, the gas engine heat pump coefficient of performance is 20-30% less than the expected COP of 1.5 – 1.6. The project team determined that the issue is related to back pressure across the heat pump evaporator coils. Additional exhaust fans are needed to increase the air flow across the coils. The team has procured the exhaust fans and has an agreement in place for a contractor to install these booster fans. Metering will continue.

The Issue

There are over 10,000 apartment buildings in Los Angeles and Orange counties. The multifamily market has been slow in adopting emerging energy efficiency technologies due to lack of technologies in the marketplace and a lack of service providers. Common central water heating systems in multifamily apartments use approximately 200-250 therms of natural gas per apartment each year, and most have never received energy efficiency retrofits.

Project Innovation

This project demonstrates an innovative high efficiency central hot water heating design for multifamily buildings. The design integrates a gas engine heat pump with solar thermal evacuated tube collectors and hot water controls and has the potential to reduce natural gas use by 75%. The project is being implemented at an existing apartment building in Los Angeles County and seeks to demonstrate a cost-effective strategy to mitigate the Aliso Canyon gas leak by reducing building natural gas use and lowering emissions. Performance evaluation and cost analyses are being conducted to determine system sizing requirements to optimize energy savings, GHG reductions, and cost-effectiveness of the integrated system.

Project Benefits

This project addresses market barriers to widespread adoption of the gas engine heat pump and solar thermal evacuated tube collector technologies by analyzing high-quality field performance data needed to optimize system sizing and maximize energy savings at the lowest cost. The project seeks to overcome a lack of consumer and installer awareness and demand in these technologies by demonstrating the integrated system at an apartment complex owned by one of the largest property management companies in the United States. This property owners operates many other multifamily buildings in Southern California. If the research can successfully validate project cost-effectiveness, the property owner is committed to replicating the technology solution at its other building sites and informing other multifamily building owners of this high-efficiency technology solution.