Project Overview:
The home, occupied by four adults and two children, previously relied on a gas-fired boiler and a 50-gallon water heater for both heating and domestic hot water (domestic hot water). By integrating Sunamp’s Thermino heat batteries, the project maximized the use of PV-generated electricity, pre-heating the boiler and significantly reducing reliance on natural gas. This smart integration of renewable energy not only lowers emissions but also reduces energy costs, proving the effectiveness of thermal storage solutions in achieving sustainable, energy-efficient homes.
Problems to be addressed:
- Heavy reliance on fossil fuels: The home’s heating and domestic hot water (domestic hot water) systems depended on natural gas, contributing to high emissions and energy costs.
- Underuse of solar PV system: The existing solar PV system was not fully optimized to meet the household’s heating demands, limiting its efficiency and potential savings.
Existing System Overview:
The home currently relies on a 50-gallon gas water heater for domestic hot water (domestic hot water) and a gas boiler to supply the heating system
The Sunamp Solution:
The Sunamp Thermino 80i, featuring phase change material (PCM) P58, is utilized to provide both domestic hot water (domestic hot water) and pre-heat for the gas boiler. The system is integrated with solar PV, which charges the thermal storage battery, enabling the storage of thermal energy at 136°F. The hot water outlet from the first hydronic circuit of the Sunamp thermal battery is blended to maintain an optimal temperature of around 120°F for domestic use. A second thermal storage battery supplies hot water for space heating, further optimizing energy efficiency and reducing reliance on fossil fuels.
Results and Findings
Thermal Battery Usage Patterns:
A heatmap analysis reveals key usage patterns of the thermal battery, highlighting the relationship between charging events and hot water demand. The data shows that maximum hourly average power draws of up to 3 kW can occur at nearly any time throughout the day, with the most common usage period being between 5:00 AM and 9:00 PM. This suggests a high demand for hot water and heating during daylight hours, while standby losses are offset by the thermal storage system.
Solar Energy Efficiency for Domestic Hot Water (domestic hot water) Needs:
On 85% of days, the solar production was sufficient to meet 100% of the energy required by the thermal battery for Domestic Hot Water (domestic hot water). However, during the remaining 15% of days, solar production fell short of domestic hot water energy demand, with these shortfalls primarily occurring between the months of December and February. This seasonal variation is common, as solar energy generation typically decreases during the winter months due to shorter days and lower sunlight intensity.
Monthly, the thermal storage battery consumed between 16% and 88% of the electricity generated by the solar system. In terms of total home electricity usage, the battery accounted for between 11% and 32%. These consumption patterns highlight the varying efficiency of the system in utilizing solar energy for thermal storage needs, depending on factors like solar production and household energy demand.
Impact & Conclusion: Enhancing Energy Efficiency and Sustainability
Energy Efficiency
On an annual basis, solar PV provided 85% of the household’s Domestic Hot Water (domestic hot water) energy demand. Charging the thermal battery via the internal electric resistance heater consumed an average of 12.9 kWh per day, equating to an annualized energy consumption of 4.72 MWh. This efficient use of solar energy significantly reduced reliance on grid electricity.
Environmental Benefits
The use of solar energy to meet domestic hot water needs resulted in a reduction of 1.16 tons of CO2e annually, contributing to an impressive 81% decrease in greenhouse gas emissions compared to the previous gas-powered hot water system. This shift to solar energy offers substantial environmental advantages by reducing the home’s carbon footprint.
Cost Savings
Solar energy production has delivered considerable cost savings to the homeowner, reducing overall electricity costs by $1,179 annually. Of these savings, $330.43 (28%) is directly attributed to the energy used for domestic hot water, showcasing the economic benefits of integrating solar PV and thermal storage systems in residential settings.
NATURAL GAS SAVINGS?????
Enhancing Thermal Storage with a Diverter System and Smart Panel Integration
Integrating a diverter system or a smart panel, such as SPAN, could significantly improve the performance of the thermal battery system by maximizing the use of solar PV-generated energy. For this particular residence, the reliance on a net metering approach provided a basic solution for managing energy, but incorporating smart technology would optimize energy consumption, reduce reliance on the grid, and further enhance the overall efficiency of the system.
By redirecting excess solar energy to charge the thermal battery or serve the household’s heating and hot water needs, this upgrade would ensure that solar power is fully utilized, reducing energy costs and boosting sustainability.
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.