Heat Pumps Help Co-op Cut Costs and Avoid Local Law 97 Fines

Faced with an initial Local Law 97 penalty of $80,000 for excess carbon emissions, the co-op board at 525 E. 82nd St. needed to decide how to upgrade the building’s outdated heating and cooling system. In the summer, the gas-powered boiler was running a low-pressure absorption chiller for its air conditioning needs.

“It was very inefficient," says Michael Scorrano, founder of the consultancy En-Power Group, which was hired by the board.

Avoiding hefty penalties was important for the board, but wasting energy was also a concern. “It became evident that replacing the absorption chiller with heat-pump technology was the best approach,” Scorrano says, adding that any building that is centrally cooled and continues to use fossil fuel is a prime candidate for electrification. Rather than burning fuel to create heat, heat pumps move heat energy from one place to another — from indoors to outdoors during the cooling season, and from outdoors to indoors during the heating season. Instead of a refrigerant solution in the pipes of each apartment’s individual air conditioners, the pumps circulate water chilled by the heat pumps.

Making the switch, however, required amping up the electrical load for the air conditioning units — literally. “What we find is that generally there’s at least enough capacity coming from the street into the building, which means the upgrade can take place,” Scorrano says. To increase the load inside a building, a request for service must first be made to Con Edison. 

However, it can often be a challenge to meet adequate working space allowances, or safety clearances, that are mandated by the Department of Buildings (DOB). Installing a larger electrical capacity system at the co-op required more space than was available in the 1960s-era building. It also required the manufacture of customized switchgear, the centralized collection of circuit breakers and fuses.

“After some back-and-forth with the manufacturer and discussions with the DOB, we were allowed to move forward with the design that was sufficient to meet the clearances,” Scorrano says. This allowed the team to increase the power in the building by 200 kilowatts. “Without that increase, we wouldn’t have anything that would power the equipment."

The six heat pumps, with a cooling capacity of 30 tons each, were installed in the building’s basement mechanical room. Their modular design allowed the building to avoid the high cost of opening up a garage wall to install the new chiller equipment. “Instead," Scorrano says, "the modular pumps fit through the doorway, and you bolt them together in place in the room.” 

The project cost was $900,000, which included the installation of new pumps with variable frequency drives. These allow for added flexibility to the system so pumps are not working at 100% all the time — which allayed the board's concern about wasting energy.

“If you look at the $900,000 that the board invested, and if you take into account the future savings as well as the carbon penalty avoidance, this project should pay for itself in five years or so,” Scorrano says. The building no longer burns natural gas in the summertime for cooling, although natural gas will continue to be used throughout the year to heat the domestic hot water.

“By putting in properly sized pumps with variable frequency drives and slightly reducing the operating speed of those pumps, we were definitely able to increase efficiency,” Scorrano says. And avoid Local Law 97 penalties. And help the climate. All in all, a win-win-win.