Introduction
As a part of NYSERDA’s NextGen Buildings Innovation program, Sunamp installed its PCM heat batteries in a multifamily apartment building with 101 units in Troy, NY.
Sunamp’s thermal storage technology has been installed to reduce energy consumption and emissions associated with domestic hot water (DHW) production.
The previous system relied on three gas-fired boilers that deliver DHW to the apartments. In this project, three Sunamp Thermino 300 thermal storage batteries with P43 were used to preheat water for the gas-fired boilers, with the storage batteries charged by a water-to-water heat pump linked to the building’s geothermal loop. This loop currently serves as the source of heating and cooling for the apartments.
By preheating the water supplied to the gas-fired boilers to 109°F, the system was set up to cut gas for DHW.
Multifamily Apartment Building - Troy, NY
Existing system
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
Proposed solution
The modified installation consists of a ground-loop geothermal water to water heat pump with 42.3 kBtu/h capacity which charges the phase change material (PCM) in three Sunamp Thermino 300 thermal batteries (PCM43/110). The thermal batteries act as a thermal store providing preheated water to the gas-fired water heaters. This decouples instantaneous water heating with the demand for domestic hot water.
Heat pump details
TruClimate 100
Formerly Versatec Ultra NSW
Commercial 60 Hz
Water-to-Water Heat Pump
• R-410A Refrigerant
• 1.5-6 Tons
• COP: 3.5
Thermino P43 details:
Charging controls
• Stop HP – Lower Sensor: 50°C (122°F)
• Start HP – Middle Sensor: 35°C (95°F)
Operational conditions:
• Water IN: between 1.6°C (35°F) and 5.5°C
(42°F)
• Water OUT: between 32°C (90°F) and 40.5
°C (105.5°F)
• Max Flow Rate: 5gpm
• Storage capacity Thermino 300 P43: 8kWh
Water inlet & outlet temperatures:
Water inlet & outlet temperatures:
The cold-water temperature ranged from 38°F in February to 74°F in warmer months. The HP and thermal batteries effectively boosted this water to preheated water temperatures of 86°F to 106°F.
Natural gas emission:
Conclusion:
Integrating Sunamp thermal batteries with a heat pump cut down the building’s natural gas use for hot water by 23% and total energy and emissions by nearly 20%, compared to tank water heaters (TWH) alone. By preheating water to 37°C (100°F) rather than starting from 4°C (40°F), the system greatly reduced the load on gas-fired boilers.
Analysis over a broader range of data, with the 23% difference in natural gas consumption, showed annual savings amount to 180.1 mmBtu (33 MWh) in gas and a reduction of 14.1 tons of CO₂ emissions. There still are opportunities for improving overall system efficiency even more with design improvements, such as minimising the effect of cold water bypass from the pressure relief valve.
Overall, this system supports electrification efforts, offering a clear path to lower natural gas use and net GHG emissions in multifamily buildings.