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New York City is at the forefront of the building decarbonization effort. But one of the primary hurdles for meaningfully reducing the city’s carbon emissions footprint remains the lack of an efficient and affordable solution for electric heating and cooling — “especially for many of the tall residential buildings that comprise our portfolio,” said Greg Russ, chair and CEO of the New York City Housing Authority (NYCHA).

NYC is aiming to address this green energy gap through its new “Clean Heat for All Challenge,” using custom window heat pumps specially designed for the project by electric heat pump manufacturer Midea America Corp.

“We’re developing a brand-new innovative product for this initiative,” said Adam Schultz, research and development manager at Midea America Research Center Residential Air Conditioning. “Everything about the unit will be new — including a new saddle form factor that will drape over the windowsill giving the consumer a view from their window again.”

The “Clean Heat for All Challenge” is a public-private initiative spearheaded by NYCHA, New York Power Authority (NYPA), and New York State Energy Research and Development Authority (NYSERDA). Under New York City Local Law 97, part of the New York City Climate Mobilization Act, NYCH must cut greenhouse gas emissions from its housing developments by 40% by 2030 and 80% by 2050. NYCHA has 300 housing developments with 177,000 apartments, and three-quarters of its emissions come from old heating systems that run on natural gas.

Midea was designated as a primary partner to develop and deliver 20,000 cold-climate packaged window heat pump units for use in New York City Public Housing facilities, with the twin goals of better serving the heating and cooling needs of existing multifamily buildings and helping expedite the transition away from fossil fuels.

Innovation at Work

The team at Midea faced two primary challenges in designing the new unit: NYC’s cold climate, and retrofit installation in apartment buildings, which brings cost barriers like electrical system upgrades, lengthy refrigerant piping, and through-wall drilling and penetrations.

“The main innovation of this challenge is the cold climate heat pump technology that will allow consumers to use this unit to heat their spaces down to -13°F, which is significantly lower than current window heat pump options,” Schultz said. “To start, we’ve used our experience in mini-splits and the DOE Cold Climate Heat Pump Challenge to incorporate technology like vapor-injection compressors to aid in low-temp heat pump heating.

“However, the biggest challenge managing ice and frost formation as well as condensate after defrost,” he continued. “Anybody familiar with traditional window air conditioners is most likely familiar with the water that may drip on the outside of the unit or maybe drips onto your unit from another unit above if you’re in the city.”

NYPA had strict requirements in this challenge around managing this condensate and making sure it doesn’t drip down the buildings, so that was a big challenge Midea had to design around.

“We’ve accomplished this through the use of reheat loops, specific defrost cycles, and an innovative condensate system,” Shultz reported.

Due to the cold climate performance of the design, the condenser is much larger than typical window air conditioners, which presents installation challenges in fitting it through the window.

“This particular challenge inspired the unique design of having the pivoting outdoor unit so it can easily go through the window,” Shultz said. “Since the new design is a saddle form factor that drapes over the windowsill, we had to consider the wall thicknesses and various window ledges that may protrude below the outside of the window so that the unit can work with the various properties.”

To accommodate this, Midea incorporated a telescoping feature that allows users to adjust for varying wall and ledge thicknesses. The design team also had to make sure the units worked with existing 15A wall outlets.

CUSTOM SIZE: The Midea heat pump units have a telescoping feature that allows users to adjust for varying wall and ledge thicknesses when installing the units. (Courtesy of Midea)

Dual Benefits

The new technology will benefit residents as well as contributing toward NYC’s climate protection goals.

For New York City Public Housing residents, it will mean the ability to control their own heat for the first time.

“That may sound trivial, but in large buildings with radiant heat, many residents don’t have any control over the indoor temperatures during heating conditions,” Schultz said. “This unit will give that control back to the resident.”

It will also provide them with a/c — something not all residents have access to — since it’s an all-season window unit.

The units will use low-GPW R-32 refrigerant, aiding in state and federal initiatives such as in the AIM Act, and will factor into overall electrification initiatives, reducing the need for fossil fuel heating at the properties where they are used.

Midea has a seven-year contract for the project. Over the next year, NYPA will work with Midea to develop the proposed heat pump technology for testing and demonstration. NYPA will then collaborate with NYCHA to install pilot units in designated public housing before moving forward with the widespread installation throughout the following years.

“At a retail level, these products should be eligible for the High Efficiency Electric Home Rebate Program, which is Section 50122 of the Inflation Reduction Act,” Schultz added.