Batch heaters are best suited for two to four person households (30 to 40 gallons (110-150 l) daily hot water requirements) in climates where freezing is rare. Their size is generally limited as the tank in the collector is integrated.
Several collectors in series for greater capacity to be installed. The outlet is the first collector to the entrance of the second to deliver higher temperatures. Before you put too many on your roof view that a 40 gallons (150 l) batch heater is about £500 (225 kg) weight.
Some batch heaters have survived the coldest winters with frost-free performance, because the vast majority of the water tank to freeze whole is tolerant. But piping to and from the tank are very vulnerable. You can so that it works twice a well insulated with a special selective surface on the tank glass collector, a whole series of well closed pipe insulation (try R-30 or better), heat tape on the pipe, and good karma.
You are arrogant enough to mother nature lure, to make your water heater in a frozen fountain? Or are you prepared, seasonal run the collector? If not, this system not for will freeze regularly climates recommended.
Separate Collector & Storage
The simple design of a batch heating detrimental to the effectiveness of collector and storage functions. Heating the whole water tank at once will the day take to produce useful temperatures. Once hot, had to use, one better that hot water at the end of the day, before the poorly insulated tank loses his precious warmth in the cold night sky.
The most solar hot water system designs separate the collector from the storage tank. This can be to optimize both functions. Why not the tank from the cold insulate well and let the collectors in the Sun where they belong?
What are the other advantages of separating the collector from the storage tank? Enlargement of the surface of a collector, compared to the amount of water that is heated and its temperature will rise faster. Configure the store to keep the hottest water apart from the coldest water in the tank and're going to have warmer water more quickly available. (See box preserve temperature stratification in the tank.)
There are also advantages for icy climate. By separating the collector from the tank, can your tank and lines in the Interior from a cold environment, and better isolate them more efficient.
Flat Plate Collectors
Flat-plate collectors are the most common solar thermal collectors. They are best suited for applications at low temperatures (below 140 ° F, 60 ° C), such as hot water and space heating.
A flat plate solar thermal collector consists mostly of copper is equipped with a flat absorber plate. The most common configuration is a series of parallel tubes at each end through two tubes, the inlet and outlet lines connected. The flat plate arrangement is contained within an isolated box, and with low iron content, tempered glass. (See the chart on page 45).
The most efficient design of the collector maximizes solar heat gains, minimizes heat loss and provides for a most efficient heat transfer from the absorber plate Tube. Operating temperatures up to 250 ° F (121 ° C) are available, although neither common nor desirable. Keep in mind you want to hot water, not steam.