Introduction
As part of the NYSERDA NextGen Building Innovation Program, Sunamp installed Thermino heat batteries in a single family house in Long Island, NY, to reduce fossil fuel dependency and optimise renewables. This project supports New York State’s ambitious goal of achieving an 85% reduction in greenhouse gas emissions by 2050, showcasing how innovative thermal storage can accelerate the transition to clean energy in residential buildings.
The residence is home to four adults and two kids and previously relied on a gas-fired boiler and a 50-gallon water heater for heating and domestic hot water (DHW). Sunamp integrated Thermino heat batteries into the project, which maximized the PV-generated electricity and supplied pre-heat to the boiler, proving how renewable energy can efficiently be used to cut annual household gas consumption significantly – cutting emissions and saving energy costs.
Challenges:
• Reliance on fossil fuels for heating and DHW.
• Underutilization of existing solar PV system for heating.
• Lack of access to US-based diverters, limiting solar PV optimization.
Existing system:
A 50-gallon gas water heater producing domestic hot water and a gas boiler supplying the house heating system.
50-gallon water heater
The Sunamp solution
Sunamp Thermino 300i (with the phase change material: P58) supplying domestic hot water and pre-heat to the boiler. The solar PV charges the thermal storage battery electrically, storing thermal energy at 136°F. The hot water outlet temperature from the first hydronic circuit in the Sunamp (P58 PCM) thermal battery is blended to achieve a temperature around 120°F. A second battery to be connected in the future to supply hot water for the space heating system.
Sunamp Thermino heat batteries 300i
Monitoring & results
The heatmap shows usage patterns from the thermal battery relating to charging events and direct heating needed as hot water was served to the home and standby losses were offset.
The heatmap shows maximum hourly average power draws of approximately 3 kW could occur nearly any time of the day, with 05:00 to 21:00 being most common.
The addition of a diverter system to maximize solar PV-generated energy would be an improvement for the system. For now, diverters are not offered in the US, so the improvement can be made in the future when the equipment is available. This particular residence relied on a net metering approach.
On 85% of days the solar production was able to meet 100% of the energy needed by the thermal battery for DHW. The remaining 15% of days had solar production lower than the DHW energy demand and occurred primarily between the months of December and February.
Monthly, the thermal storage battery consumed between 16% and 88% of the electricity generation, and between 11% and 32% of the total home electricity usage.
Impact & conclusion
Energy efficiency
85% of the household’s DHW energy demand was met by solar PV on an annual basis. Charging the thermal battery via the internal electric resistance heater consumed an average of 12.9 kWh/day, which represents annualized energy consumption of 4.72 MWh.
Environmental benefits
Solar energy use reduced greenhouse gas emissions by 1.16 tonnes CO2e annually, achieving an 81% reduction compared to the previous gas hot water system.
Cost savings
• Overall, solar energy production saved the homeowner $1179 per year in electricity costs for the entire home, with $330.43 (28%) of savings per year attributed to DHW.
