The following viewpoint is written by Dana Adiguzel, Senior Mechanical Engineer/Team Leader at LaBella Associates
The electrification of multi-family housing at scale remains one of the most difficult challenges in the decarbonisation of existing buildings. Many apartment buildings in New York rely on centralized steam systems or gas-fired hot water boilers that are difficult to replace without significant disruption to residents.
As part of NYSERDA’s Empire Building Challenge, LaBella Associates partnered with Chartered Properties and Sunamp Optimized Thermal Systems to develop a replicable retrofit model designed to electrify these buildings while allowing construction to occur in phases with minimal disruption to residents and owners.
Selected as the winning team in the program’s third cohort, the partners are developing a plan that property owners and developers across the state can use to accelerate multifamily decarbonization. Their approach demonstrates how architecture, engineering and technology can work together to create cost-effective electrification pathways for existing buildings.
The challenge of legacy systems
The legacy mechanical systems of many multi-family buildings tend to rely on central steam or gas hot water boilers and radiators for primary heating, with domestic hot water supplied via indirect tanks connected to these same boilers.
Reducing environmental impact while improving resident comfort and control requires a significant change in system design.
LaBella was challenged by Brooklyn affordable housing developer Chartered Properties to design a scalable, replicable decarbonization strategy that could be seamlessly implemented across multiple multifamily designs.
Innovation through thermal storage
The core of the design focuses on energy efficiency and the use of thermal storage to ease peak demand on the electricity grid.
Thermal batteries are critical to the electrified system as they help manage energy demand while avoiding excessive utility costs for residents.
The system uses compact thermal batteries that store thermal energy and release it when needed for domestic hot water and low-temperature hydronic heating.
The thermal material inside the batteries can be “charged” by hydronic heat exchange or electricity. When charged with electricity, the batteries can store energy during off-peak hours when utility prices are lower.
Stored energy can provide domestic hot water and low-temperature hydronic heating during periods of peak utility, reducing electricity demand and potentially reducing energy costs by up to 35%.
Although utility costs differ across the state, an alternative means of charging can be used when utility rates are constant.
By integrating air source heat pumps with the thermal battery system through the use of a coolant-water heat exchanger, the thermal batteries can be hydronically charged with hot water produced from the heat exchanger.
The high coefficient of performance (COP) of the heat pump takes advantage of greater electricity efficiency, allowing a similar reduction in utility costs than off-peak load capacities.
Taking the design a step further, energy recovery boxes can be integrated into the heat pump system to redirect hot gas refrigerant leaving the residence’s indoor cooling units to the refrigerant-to-water heat exchanger to recover the heat in the domestic water system.
Bypassing the use of the system condenser to charge the thermal battery for the creation of domestic hot water further optimizes the efficiency of the system and reduces overall energy consumption.
A scalable plan for New York
The first implementation of this retrofit model is taking place at a multi-family property in Brooklyn, where the system is being deployed in several buildings with a total of nearly 100 residential units.
Moving away from centralized systems in favor of unit-by-unit installations allows for a step-by-step approach. Upgrades can occur without a knock-on effect of building-wide downtime, making the design applicable to more than 440,000 multifamily buildings in New York State that will require similar upgrades.
The project demonstrates how challenges such as space constraints and demand on the power grid can be addressed through solutions including thermal storage and heat pump integration. When architecture, engineering and technology work together, these systems create practical ways to electrify existing multifamily buildings.
Together, these strategies provide a roadmap for electrifying multifamily housing while minimizing disruption to residents and homeowners. As New York moves toward its climate goals, scalable retrofit strategies like this will play a critical role in decarbonizing the state’s existing multifamily housing stock.
Dana Adiguzel is a senior mechanical engineer and team leader at LaBella Associates, a Rochester, New York-based firm that provides comprehensive architecture, engineering, environmental, planning and energy services in the infrastructure, buildings, environment and energy sectors. of Adiguzel 14 years of experience include scoping and designing a wide range of mechanical, plumbing and fire protection systems for residential, commercial, higher education, K-12 and municipal projects. On-site, conducts field investigations, assessments of existing conditions, project scope verification, and system troubleshooting. She is also a project manager and works administrator.
