Last December, leaders in New York City voted to ban the use of natural gas in most new buildings by 2023. New York, the largest city in the country, follows other major cities such as Seattle whereas of Jan. 1, fossil fuels such as natural gas are no longer permitted in most new commercial and multifamily buildings as part of the city’s push toward greater electrification.  

These two cities are part of a growing number of communities and states encouraging efficient electric technologies to achieve climate goals. But these steps are a dramatic change for developers and facility managers who’ve long used gas to heat water in large buildings at a low cost. 

Amid these changes, a national effort is providing practical, climate-friendly solutions for commercial buildings and contractors who install large water heating systems. 

Advanced Water Heating Initiative

The Advanced Water Heating Initiative is a coalition of utilities, engineers, federal agencies, state and local governments, manufacturers and others working to scale heat pump water heater installations across the U.S. If that happens, AWHI estimates we’d save nearly 100 million tons in carbon emissions every year.

AWHI members are bringing new, accessible products to market and educating utilities, contractors and the supply chain on the value and impact of commercial heat pump water heaters.   

For example, Ecotope, a research and engineering firm based in Seattle, with support from the Bonneville Power Administration, a federal agency operating in the Pacific Northwest to market electric power from the Bonneville Dam, has spent the last 10 years working with manufacturers to develop new, easy-to-install commercial heat pump water heating systems for multifamily buildings. Because these systems are all electric and use just a third of the energy needed to power traditional water heaters, Ecotope and BPA believe these new systems can help transform the built environment.  

“These systems offer an incredible opportunity because for the first time, we have commercial heat pump water heaters that are basically plug and play,” says Jon Heller, president of Ecotope. “With these new accessible products, we can remove what are often the largest source of direct carbon emissions from multifamily buildings.” 

As for the installation and management of commercial heat pump water heaters, D+R International, an environmental consulting firm, based in Silver Spring, Maryland, in partnership with Ecotope and with the support of BPA, has created educational resources and planning tools for all industry professionals including engineers, plumbers and facility managers.

Current trainings cover topics include the following:

• System components (heat pump water heaters, primary storage, temperature maintenance systems, controls).

• An overview of code requirements, as documented in the Universal Plumbing and Mechanical Codes.

• Maintenance practices and protocols for heat pump water heaters, storage tanks, plumbing and distribution systems, and controls.

• Installation processes. 

Bayview project

Seattle’s Office of Housing recently installed a new commercial heat pump water heating systems at Bayview Tower. Located in Seattle’s central Belltown neighborhood, this 13-story, 100-unit multifamily building offers low income public housing to the elderly and disabled. 

The system at Bayview is the first installation of a plug-and-play commercial heat pump water heating system from Mitsubishi in the U.S. The ultra energy efficient system serves tenants with hot water, low utility bills and big steps toward environmental stewardship.

Installed last August, the Bayview CHPWH system includes a Mitsubishi QAHV heat pump, primary storage tanks plumbed in parallel and a temperature maintenance system that since it was retrofitted uses electric resistance tanks reused from the old system. The Mitsubishi QAHV uses CO₂ as a refrigerant, a natural refrigerant with a global warming potential of 1, and it’s a great candidate for outdoor installations in cooler climates. 

The primary plant is responsible for heating incoming city water while the temperature maintenance system keeps the water in the distribution plumbing hot. When a draw occurs, water is pulled from the swing tank and tempered in the mixing valve before moving into the distribution system. Hot water from the primary plant recharges the swing tank and provides constant passive heating. If no water draw occurs or the swing tank cools, a backup electric element engages to keep water hot.

The water heater and its components were assembled off-site and delivered on the back of a truck as a fully functional water heating system ready to be lifted into place. This approach simplified the installation and commissioning of the system for plumbing contractors. 

The system has seen a reduction from 230,000 to 95,000 kWh/year and operates three times more efficiently with a COP of 3. It’s expected to save $15,000 per year in energy costs along with reduced maintenance. 

“The system at Bayview is a perfect example of the multilevel impact commercial heat pump water heaters can have,” says Keshmira McVey, program manager of emerging technologies at BPA. “These systems are more reliable, they lower costs for owners and tenants and they can dramatically cut emissions from buildings which are often cities’ largest energy users.”

BPA, Ecotope and the AWHI are seeking to shift the market for multifamily and other commercial buildings to heat pump water heaters over the next five years. Visit advancedwaterheatinginitiative.org for more information and the free resources available.

Heat₂O

Heat₂O from Mitsubishi Electric Trane HVAC (METUS) is an all-electric heat pump water heating system designed to produce high volume domestic hot water for commercial facilities.

DHW accounts for roughly 25 percent of annual energy usage in typical multifamily buildings and is the largest single energy use of energy for new multifamily construction in the Northwest 

The Heat₂O heat pump water heater reduces the environmental impact of DHW through energy-efficient operation while using CO₂, a natural and environmentally friendly refrigerant with a global warming potential of 1 and an ozone depletion potential of 0. 

Able to produce high volume DHW without fossil fuels, Heat₂O can help multifamily buildings, offices, hotels, gyms, educational institutions and other large-scale and commercial facilities qualify for sustainability certifications or achieve zero-energy and passive house status 

The system includes pre-assembled and pre-plumbed components designed and selected to ensure installation quality and ensure optimal performance of the heat pump. Components include hot water storage tanks, swing tanks, secondary heat exchangers and variable-speed secondary circuit pumps. 

Heat₂O transfers ambient thermal energy from outdoor air to potable water by cycling refrigerant. Natural CO₂ refrigerant enables Heat₂O to supply hot water up to 176 degrees even in low ambient conditions without burning fossil fuels. 

Using Mitsubishi Electric’s patented Twisted Spiral Gas Cooler, the system achieves highly efficient heat exchange with three refrigerant lines wrapped around a twisted water pipe.  

The CO₂ refrigerant flows in the opposite direction of the water. Running the refrigerant lines along the pipe’s grooves increases the heat conductive area while the spiral helps create a vortex in the pipe, accelerating the turbulence effect of water and reducing pressure loss in the heat exchanger. Additionally, the copper pipes make for double-walled construction. 

An INVERTER-driven scroll compressor increases Heat₂O’s energy efficiency by enabling the system to modulate refrigerant flow and heating capacity to match loads.  

To learn more about the Heat2O heat pump water heating system, visit MitsubishiComfort.com and Heat2O.com.

Leslie Heilbrunn is the director of brand and strategy at Ecotope, a Seattle-based research and engineering firm focused on counteracting the climate crisis with scalable, low-carbon solutions for the building industry.