Pushing the Boundaries of Electrification

The board at 420 Beekman Hill, a 110-unit co-op at 420 East 51st St., is pioneering large-scale heat pump technology to meet the city’s Local Law 97 emission requirements. The ambitious $3.2 million project will replace the building’s steam heating, cooling and hot water system with rooftop heat pumps and basement heat exchangers, something that is rarely seen on this scale in older buildings. It will enable the co-op to meet its 2049 emission goals next year. Their project was facilitated by the NYC Accelerator, a clean energy incubator.

“We are going to prove that you can do this affordably,” says architect and board member Randolph Gerner. The co-op is receiving incentives from Con Ed and NYSERDA, which amount to over $1 million, or one-third of the cost of the project.

A unique feature of the building is that it does not have a boiler. Instead, the building is currently one of 250 Con Ed clients using steam for its heating and cooling needs. The service area for this type of heat distribution runs from the southern tip of Manhattan to 96th Street. While Con Ed is committed to decarbonizing its steam system by 2050, it’s more expensive than other fuels. “Many buildings have, over the years, converted to boilers,” says Michael Bendjouya, president of Controlled Combustion, the contractor doing the work at the 13-story building. Beekman Hill is leaping over this fossil fuel route and going fully electric with heat pumps for heating, cooling and domestic hot water.

Heat pump technology is popular in smaller buildings of up to five or six stories because small scale conversions are much easier and much less expensive than bigger projects, according to Jordan Dentz, vice president of New York operations at the energy consulting firm MaGrann Associates. “These projects get exponentially more complicated as they get larger,” he says.

Adding to the complexity of Beekman Hill’s retrofit is the fact that steam pipes cannot be utilized on the new system and the existing hot and cold water risers needed to be relocated. This means new condenser risers need to be installed up to the roof, where the heat pumps are installed. “The risers that were used for the Con Ed Steam system are going to be abandoned” Bendjouya says. However, branch lines to apartments can be reused and the existing fan coil units will also work with the new system, minimizing disruption inside shareholders’ apartments. Another challenge with a large-scale heat pump installation is increasing the electric load capacity to run the equipment. Part of the project at Beekman Hill is to run a new 4,000-amp electric service to the roof.

Domestic hot water will be generated by water cooled heat pumps located in the existing Con Ed Steam Room. “Recapturing heat is part of our program,” Gerner says. Most large-scale retrofits are not going this far. “It’s an option that results in a more efficient system but costs more,” Dentz says.

The funding for the electrification will come from a short-term loan from the co-op’s existing bank. A special assessment will allow shareholders to pay the loan down. “We have very forward thinking residents in our building,” Gerner says, adding that the board vote to carry out the project was unanimous even before the full credit from the incentives was calculated. The heat pump air conditioning system is expected to be operational by May 2024 with the rest of the work to be completed by the end of next year.