Researchers identify best spots for Californian solar water heaters

Nearly half of America’s residential water is heated by methane gas. In California, a quarter of a typical household’s energy budget goes into water heating. To reduce reliance on methane gas, state legislators voted to ban gas-fired space and water heaters by 2030 and are encouraging a switch to solar-heated systems or heat pumps.

Several methods exist to collect solar energy for heating water, but a novel device that uses aluminum minichannel tubes is the most thermally efficient and boasts low maintenance costs. Mondal et al. investigated the optimal placement locations of these minichannel water heaters across California.

“The study was part of a grant from the California Energy Commission that intended to reduce methane emissions from natural gas leaks,” said author Gerardo Diaz. “This was in response to the large gas leak at the Aliso Canyon natural gas storage facility in California that leaked for several months during 2015.”

Using data from a solar collector installation at a single-family home, the researchers developed a simulation tool that they combined with weather data and solar resource availability across the state. A clustering machine learning technique identified the best locations to install solar collectors. The results showed that many areas across California could benefit from minichannel solar water heaters. Additionally, the methodology could be replicated anywhere on Earth.

“The results of the study can be used to generate a robust energy policy that benefits the population in many parts of the world,” Diaz said. “Results also show significant potential to reduce methane emissions which will have a significant impact in reducing the effects of climate change.”

Source: “Data-driven optimal placement of minichannel-based solar water heater using satellite-derived and ground-telemetry weather information,” by Sourov Kumar Mondal, Sai Kiran Hota, Hugo T.C. Pedro, Carlos F.M. Coimbra, Edbertho Leal-Quiros, and Gerardo Diaz, Journal of Renewable and Sustainable Energy (2024). The article can be accessed at https://doi.org/10.1063/5.0194845 .