A new invention water heater system will improve hot water heating efficiency by using cold water. It works similar to a heat pump, but instead of using the air temperature difference, it uses the water temperature difference of fresh cold tap water. Inventor Hal Slater and a research team from the University of California tested prototypes in three home areas with different temperatures of cold tap water: a coastal home, a mountain home and a desert home, then compared the performance of the monitored machines for a year. They found the warmer the outside temperature, the more efficient the heat to extract. When the inside and outside water and temperature were similar, the system basically reverts to an electric water heater.
Test results showed an improvement in water heating efficiency by as much as 50% over leading heat pumps, and believe that with a few tweaks efficiency could be increased by 100% – as efficient as the best solar water heaters, but without a solar panel.
Thanks to Gizmag for this article.