The historic cost declines of solar panels make Photovoltaic Domestic Water Heating an attractive possibility for widespread domestic water heating. As far back as 2012, Mark Holladay of Green Building Advisors predicted the decline of flat plate and vacuum tube solar collectors. Now, thousands of homeowners in Nevada could find heating large, well-insulated water tanks can ensure their solar panels maintain value.
Solar thermal is the oldest kind of solar energy, and it has been around for hundreds of years. Solar thermal never reached widespread adoption in the United States and remains dependent on tax credits to maintain their small sliver of a market. They are subject to leaking, and can be difficult to service. Solar thermal is a cost effective DIY, hobbyist project but is unlikely to be the solution to carbon-free water heating.
Nearly all Americans heat their water with gas and grid power. When homes have a natural gas connection, the cheapest option is currently natural gas. However, it has become increasingly clear that natural gas is not the environmentally friendly bridge to clean energy that many had hoped.
The natural gas leak outside of Los Angeles has turned much of California against the industry. As relaxed policy and oversight is reversed, natural gas will be considerably more expensive. The leak has many Californians looking to the sun for their hot water, and now may be the time for solar PVDHW.
Additionally, utilities have begun pulling back on net metering in states like Nevada and Hawaii. This means there are thousands of solar photovoltaic systems on roofs that will be compensated around $.02/kWh instead of the $.14 they were expecting. PVDHW presents an opportunity to get more value out of solar panels by connecting them to a water tank that stores the heat until needed.
Sunbandit has been trying to commercialize Photovoltaic Hot Water for several years. They have broke many barriers, and proven the concept with certifications by Energy Star, UL, ICC-SRCC OG100 and OG300. The certifications open the door for tax benefits and other incentives traditionally applied to solar photovoltaics.
But for solar heat to last around the clock, the tank must be considerably larger. It must be well insulated, and it must employ a heat exchanger. Sisyan LLC has installed 4 such systems in Baja California and Nevada.
We recommend a tank capacity of 1.1 m3 for a single family home. The insulation should be 25-35R. Since the maximum water temperature will be below 60C, roto-cast technology is recommend for the tank.Heat Exchanger – HXThe heat exchanger is made out of 50m of CT SS 316L, 1” diameter tubing.Tubular Heat Element -30 VDC/250WElectrical ControlsSRCC testing has been initiated and the certification is forthcoming.