Solar Powered Water Heaters in Frost Prone AreasThese solar powered water heaters have a liquid running through the heat collecting panels is not the household water. It is a solution of antifreeze, commonly water mixed with ethylene glycol. This is similar to the fluid used in the radiators of cars and is definitely not suitable for human consumption. The heat collected from the antifreeze solution is then transferred to a preheating tank. The household water is then piped from the hot water service through this preheater and then back to the service. There is no risk of contamination of the household water from the ethylene glycol since the two do NOT come into direct contact.
Some systems dispense with the preheater tank and run the heat exchange directly through the hot water service. If this is the case the heat exchanger needs to be of very good quality, particularly if the antifreeze solution is toxic. These systems may be a little cheaper than ones that incorporate a separate preheater tank as they dispense with one tank and the extra plumbing, pump and controls associated with moving the hot water service water through the additional tank. As you would expect, these solar water heater systems are more expensive than the standard active or passive systems. There is more equipment and plumbing involved and so therefore greater material and labor costs for installation. There will also be more maintenance involved with a system like this since there are more components, and the antifreeze solution will have to be replaced periodically. The time for this could be anywhere from 3 to 10 years depending on the model you choose. That said, these systems are still effective at reducing your home hot water bill. The return on investment for these systems will of course take longer, and is also dependent on what climate you live in. Make sure your installer can answer questions about the efficiency of this type of system in reducing your water heating energy use. |
