Drainback Solar Thermal System Design
Thermal
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Drainback Solar Thermal Systems
If you think a drainback solar hot water system fits your needs, you must consider a wide variety of rules, limitations and requirements, as outlined below.
Array choice and mounting
The choice of collector array for drainback systems is more complicated than for a pressurized system: some evacuated tube collectors cannot be used at all (check with the manufacturer) and any collectors that use serpentine riser tubes are also ruled out.
Solar Thermal Pressure Gauges and Thermometers
Pressure gauges
Assuming you're installing a closed-loop, pressurized solar thermal system, a pressure gauge is absolutely essential. You can place it almost anywhere in the loop, but it's best to locate the gauge close to the charging ports.
Solar Thermal for Pool Heating
The single biggest use of solar thermal systems worldwide is to heat swimming pools. As a result, special technologies have appeared that facilitate this use, the best of which is a web-and-tube setup. The requirements for seasonal pool heating are much simpler than those for a whole-home, all-season solar thermal system: the water only needs to be heated to a little above ambient temperature, the collectors don't need to be climate-proof (as they're only laid out in hot months, when needed) and they don't need any glazing.
What are Solar Thermal Storage Tanks?
It doesn't matter whether you're installing a huge solar thermal system to heat the water for an entire community or a small residential setup to lower your power bills: you'll need a storage tank to keep hot water in. And since the sun has an annoying tendency to be weaker in winter and disappear at night, that tank needs to be insulated to keep your water hot as long as possible.
Solar Thermal Storage Tanks
Tanks with Integral Heat Exchangers
Heat Exchangers for Solar Thermal Systems
Solar thermal installations use liquid-to-liquid heat exchangers exclusively: on one side, there's the solar fluid that travels from the collector; on the other there's the water being heated.
Pumps for Solar Thermal Systems
The pumps used in solar thermal installations come in both AC and DC models. It is important to choose a model that not only fits your electrical supply but which is also compatible with the rest of the system, in terms of construction materials.
Heat Your Pool with Solar Power
Pool Heating with Solar
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