Capturing Heat When You’re Catching a Cold
Customers and curious enquirers are always surprised by how well solar hot water heaters work, even in cold temperatures. Not just a cloudy day, but in the cold grasp of winter, solar evacuated tube systems are able to keep hot water pumping and saving their owners money.
In New York, during the wintertime, when the ambient temperature is some -15°C, a solar hot water heating system can continue to pump out water at 80°C.
Solar hot water systems have even been known to operate in the coldest regions of the Arctic Circle. In the small town of Kotzebue, solar hot water collectors provide the local population with hot water for their domestic needs.
The ambient temperature of these regions can be somewhere around the -30°C mark. Remarkably this is fine weather for a solar hot water heater, and in some instances it can be ideal. Constant sunlight and no cooling down period at night time in these regions allow the system to be at almost maximum efficiency.
How Is It that These Systems Fare So Well in Such Cold Temperatures?
Two key attributes allow the system to be efficient in these temperatures: the vacuumed space between the layers of glass in the solar evacuated tubes and the absorber coating.
The vacuum between the layers of glass work prevent the conduction and convection of heat. They protect the inner parts of the tube from the ambient temperature, and allow light and energy to still pass through the glass.
The result is that the metal plates of the tubes heat up with the full strength of the sun, regardless of how cold it is outside. Once captured, it is then very difficult for the heat to escape and almost all of the heat can be conducted directly into the water.
Other solar hot water systems in Australia use an anti-freeze compound of ethylene glycol that allows water to remain a liquid at colder temperatures. However, due to Apricus solar hot water system’s unique design and superior insulated properties, the system does not need any added compounds or chemicals to protect against freezing. Instead, a layer of absorber coating is used to retain heat inside the tubes even in cooler temperatures. This feature results in lower maintenance costs for consumers.