The Basics Of Solar Hot Water Systems
People have been heating water by way of the sun for over a hundred years, and this has become more popular than ever now. There are a few different variations of solar water heater systems, and each one has its place as far as climate is concerned. The benefits are many, and everyone has their reasons as to why they install solar water heating systems. Learning about the various designs and benefits will help you in your decision on which style will work best for you.
The principal is the same for whichever style you decide to use. There will be some form of solar collector mounted on a wall that faces the sun or mounted on the roof. This collector will heat a fluid that either naturally flows through the system or the fluid is circulated by means of a pump. The type of fluid will depend on whether it is a closed loop system or an open loop system.
In a closed loop solar hot water system, a heat exchanger is implemented to keep the circulating fluid separate from the existing potable water. The two most used heat transferring fluids are straight water and a non-toxic propylene glycol and water mix that won’t freeze. The fluid is first heated in the collector and then circulates through the heat exchanger where the transfer of heat to the potable water occurs. This type of system may cost a little more than an open loop system, but the advantages of protection from freezing and overheating are worth the extra cost.
In an open loop solar water heating system, your existing potable water is circulated through the collector then back to the supply tank. The supply tank is normally mounted horizontally and will be located above the collector in a natural flow system and on the main or the ground floor below the collector if the fluid is pumped through the system. ATLG Solar Hot Water explained; that this type of system is a little cheaper to install but has a few disadvantages. The main ones are lack of overheating protection unless modified, lack of freezing protection unless modified and the build up of scale in the collectors unless you install an ion-exchange softener.
As far as circulating the fluid through the different systems, they are generally referred to as either passive or active systems. The passive systems count on natural heat driven convection for circulation of the heating fluid through the system. The active systems utilize at least one pump or multiple pumps for circulation of the heat transferring fluid through the system. Passive systems are more prone to overheating and freezing while active systems are more flexible on tank location and are superior in efficiency.
As you have learned from above, there are several different systems and factors involved for solar hot water systems. All types would work in warmer climates but closed loop active systems would work best in a climate where freezing is an issue. After learning the basics for solar water heating, you should now be able to make an educated decision for which type of system will best suit your needs.