Project Overview:
Sunamp installed its phase change material (PCM) heat batteries in a 101-unit multifamily apartment building in Troy, NY, with the goal of reducing energy consumption and emissions associated with domestic hot water (domestic hot water) production.
The building previously relied on three gas-fired boilers to provide domestic hot water to the apartments. In this innovative solution, three Sunamp Thermino 80i thermal storage batteries with P43 technology were used to preheat water for the gas boilers. The thermal storage batteries are charged by a water-to-water heat pump, which is linked to the building’s geothermal loop—the same system that provides heating and cooling for the apartments.
By preheating the water to 109°F, the system effectively reduces the need for gas to heat the water, significantly cutting gas consumption for domestic hot water production.
Problems to be addressed:
The multifamily apartment building in Troy, NY, faced several challenges related to energy consumption and emissions associated with its domestic hot water (domestic hot water) system. The existing gas-fired boilers were inefficient, leading to high gas consumption and contributing to greenhouse gas emissions. The reliance on fossil fuels for domestic hot water production was not aligned with modern sustainability goals, and the aging system was also prone to maintenance issues.
Additionally, the building’s heating and cooling needs were met by a separate system, creating inefficiencies in energy management. The lack of integration between these systems resulted in missed opportunities for energy savings and the optimization of renewable energy sources like the building’s geothermal loop.
Existing System Overview:
The site has three existing 100 gallon natural gas-fired tank water heaters located in a basement providing domestic hot water to the apartments. Each water heater has a capacity of 250 kBtu/h
The Sunamp Solution:
The modified installation includes a ground-loop geothermal water-to-water heat pump with a 42.3 kBtu/h capacity, designed to charge the phase change material (PCM) in three Sunamp Thermino 80i thermal batteries (PCM43/110). These thermal batteries serve as an efficient thermal store, providing preheated water to the gas-fired water heaters. By doing so, the system decouples instantaneous water heating from the demand for domestic hot water (domestic hot water), allowing for optimized energy use and reduced reliance on fossil fuels.
Results and Findings
The cold-water temperature varied from 38°F in February to 74°F during the warmer months. The heat pump (HP) and thermal batteries efficiently boosted the water temperature, achieving preheated water temperatures between 86°F and 106°F.
Impact & Conclusion: Enhancing Energy Efficiency and Sustainability
Natural Gas Reductions
Integrating Sunamp thermal batteries with a heat pump reduced the building’s natural gas usage for hot water by 23% and cut total energy consumption and emissions by nearly 20% compared to traditional tank water heaters (TWH). By preheating water to 37°C (100°F) instead of starting from 4°C (40°F), the system significantly reduced the load on the gas-fired boilers.
Emissions Savings
Analysis of the data revealed that the 23% reduction in natural gas consumption resulted in annual savings of 180.1 mmBtu (33 MWh) and a reduction of 14.1 tons of CO₂ emissions. Further improvements in system efficiency can still be achieved through design refinements, such as minimizing the cold water bypass effect from the pressure relief valve.
Overall, this system supports electrification efforts, offering a clear path to reducing natural gas consumption and net GHG emissions in multifamily buildings.
NYSERDA NEXTGEN Building Innovation Program:
The NYSERDA (New York State Energy Research & Development Authority) NEXTGEN Building Innovation program aims to help New York State achieve a carbon-neutral economy by 2050, with a goal of reducing greenhouse gas emissions by at least 85% from 1990 levels.
The NYSERDA NextGen Buildings program is dedicated to accelerating the development and commercialization of innovative technologies that enable the electrification and decarbonization of New York State’s building stock. By supporting the adoption of cutting-edge building innovations, the program seeks to make buildings cleaner, more energy-efficient, load-flexible, and resilient in the face of climate change.
As part of this initiative, Sunamp is deploying thermal batteries at eight different sites across the state, integrating these systems with both existing and new infrastructure to deliver domestic hot water and heating in a cleaner, more energy-efficient manner.