SOL-Perpetua™ Solar Water Heating System Installation Instructions and Operating Manual For Series "A" Pumps
Components of a SOL Perpetua™ System - Storage Tank
Solar heat can be delivered to a one tank storage system or to a system with a number of tanks. Usually there is an auxilliary heater for sunless days or Deriods of greater hot water consumption. For customers wishing to use wood as the auxilliary heat source. BAPL can supplv a bubble pump and heat exchanger for connection to a boiler in their wood stove. With this system the storage tank can be located below the wood stove in a basement or crawl space. There must be a temperature/pressure relief valve at the top.
Where two or more tanks are used they should be connected in parallel. The arrangement where there is a "preheat" solar tank, that is, where water is heated by solar energy before going into the tank containing the auxilliarv heater, has been found to consume more auxilliary power than a svstem where the solar energy is delivered to the top of the tank which has the auxilliary heater in it.
One large tank reduces heat losses but may not be the most cost effective. Two 40 gallon tanks can be cheaper to buy and easier to install than one eigthy gallon tank.
A 270 litre (60 gal.) electrically heated tank usually comes with two immersion heaters, one at the l/3 point from the top, the other near the bottom. Disconnect the heater near the bottom or set its thermostat very low. This arrangement leaves approximately 2/3 of the tank available to store solar energy. On cloudy days there will be 90 litres (20 gal) of hot water on hand, being heated by electricity. When there is plenty of sunshine, however, the electric heater rarely comes on.
An efficient alternative is to use only one tank that has no heaters and supplement this with direct heaters at the point of use. It is efficient because it reduces tank losses. Point of use heaters can be expensive, especially gas fired heaters in North America.
Standard hot water storage tanks do not have the amount of insulation that is cost effective no doubt because shipping costs would be higher. Insulating blankets are not expensive and should be installed on all storage tanks. Pay particular attention to the top of the tank because this is where the water is the hottest and ironically where, because of a domed top, most tanks have the least thickness of insulation. If your tank has top outlets, cover the piping with the blanket.