Partial Electrification Yields Sizable Savings for Yorkville Co-op

Needing to meet Local Law 97 carbon-emission requirements and improve a lackluster D energy efficiency grade, the board at a 200-unit co-op in Yorkville is upgrading its cooling and domestic hot water systems by going electric. The project, with an estimated cost of $1.2 million, involves boosting the electrical capacity at the 20-story building, replacing an outdated absorption chiller with heat pumps, and reusing waste heat to drive the electrification of the domestic hot water system.

The retrofit, which will begin in the fall or early next year, will allow the gas-fired boiler to be switched off during the summer, generating an estimated $70,000 in energy savings annually. Reducing fossil-fuel use with partial electrification will also eliminate more than $100,000 in carbon emission penalties until at least 2039. In addition, the co-op hopes to take advantage of early electrification credits outlined by Local Law 97 guidelines. Under the rules, co-op and condo boards that are early adopters of electrification measures can bank the accumulated carbon savings and apply them to future compliance years. 

The first phase of the project will switch out the air conditioning system by removing the co-op’s outdated absorption chiller piece by piece and replacing it with modular electric heat pumps. Currently, the building uses a combination of steam from a gas-fired boiler and lithium bromide in the chiller to provide air conditioning for the building during the summer. “The cooling plant is so inefficiently operating that the summer gas consumption outweighs the gas usage for heating,” says Michael Scorrano, who is overseeing the work as managing director and founder of En-Power Group.

According to recent tests, the 20-year old absorption chiller still has a few more years of life left, but the building manager says replacing it with an electric alternative is a priority for the building. “Being proactive makes sense because capital projects don’t cost less over time,” he says. 

When the switch is made, the new electric heat pump will cool water throughout the building through evaporation, compression and the use of refrigerant. The water will be pumped to the same fan coil units within the apartments — typically under the window — to cool rooms. 

As before, the air conditioning system exchanges cool air with hot, picking up heat from the rooms. However, instead of expelling heat from the chillers via a cooling tower, Scorrano says this “untapped resource” will be reused so that the return water, laden with residual heat, will be repurposed to become the source energy for the domestic hot water system. “That’s the innovative approach,” Scorrano says. “We’re trying to reclaim or recycle chilled-water return and utilize that source of heat, which we currently just reject, to make hot water.” The electrification of the hot water will eliminate boiler use during the summer. “So in the summer months the building will be 100% decarbonized,” Scorrano says. 

Upgrading the electric service to accommodate the increased load is necessary for the transition. While the project is expected to receive Con Edison and NYSERDA incentives, funding will initially come from the building’s reserves. The board is also seeking a green loan to cover some of the costs. “The building can use the reserves to start and go back later with the loan to replenish their coffers,” Scorrano says.