Heating water with solar energy in the desert isn't that much of a challenge - even a coiled up hose sitting in the sun will work in a pinch - but producing solar hot water or space heating in cold climates year-round is a whole different ball of wax. However, a new highly efficient design for solar thermal collectors by TIGI Solar in Israel promises to lower the associated energy costs of heating water, especially in areas with colder climates.
On the surface of the Honeycomb Collector is a proprietary "transparent insulation technology", shaped like a honeycomb, which allows sunlight to pass through to heat the collecting surface while suppressing heat losses from convection and conduction at the same time. This design is said to be very energy-efficient, enabling the sun's energy to easily enter the collector while keeping energy losses to a minimum, even with large temperature differences between the ambient air and that inside the collector itself.
"At the heart of the Honeycomb Collector is a polymer-made layer of transparent insulation (TI). The TI honeycomb substance is transparent to solar irradiation, allowing for energy to enter the collector and heat the absorber plate. However, it creates a layer of air that cannot circulate, thus dramatically reducing losses related to convection – the major reason for energy losses and lower efficiency of flat plate collectors at high temperature differentials. In addition, the polymer blocks back radiation in the infrared, thus further reducing energy losses." - TIGI
According to TIGI founder Shimon Klier, the company's technology isn't just for domestic rooftop hot water production, but can be applied to commercial, industrial and institutional ventures, and can be implemented for space heating, sanitary hot water, or heat generation for industrial processes. In an interview with Israel21C, Klier hints at the possibilities for wider applications of the Honeycomb Collector:
"If you take Canada, where over 40 percent of the entire energy bill goes to heating, while at the same time you look at renewable energy solutions of solar thermal collectors –– there are 16 million square meters of solar thermal collectors installed for heating worldwide — almost all of them are installed in climates similar to Israel, and almost all go to domestic hot water.
And why is this? Because this is where the current solution for heating water works well. Space heating, however, is 10 times the cost on the energy bill versus heating hot water. We want to take solar domestic hot water to cooler climates, to provide applications that supply more heat." - Klier
According to TIGI, the Honeycomb Collector performs the same as (or better than) evacuated tube thermal collectors, but at a lower costs and longer life. Compared to flat plate thermal collectors, the Honeycomb is said to provide up to five times more (!) energy in cold climates and in high temperature applications, such as industrial processes. The company's design won the 2012 Intersolar Europe award (Solar Thermal Technologies) this past June.
Find out more about TIGI Solar and the Honeycomb Collector at the company's website.