Solar Thermal panels use the sun’s radiation to produce heat (whereas the Solar PV panels use it to produce electricity). The heat produced is solar panels brisbane used to heat the water in your hot water tank or cylinder so that you can enjoy FREE hot water.
A complete Solar Thermal system consists of Solar Collectors, which can either be Evacuated Tubes or Flat-Plate Collectors, along with a Pump Station and a Pressurised Twin Coil Cylinder. An antifreeze fluid (Glycol) is pumped through the solar thermal circuit reaching higher temperatures than water.
Heat that has been absorbed by the Collectors is exchanged into the Glycol solution. The heated Glycol is then pumped through the system into the bottom coil of the water cylinder and then pumped back up to the Collectors making a completely sealed circuit.
In summer months this thermal energy is enough to heat the entire cylinder, meeting the complete hot water demand. In winter months the heat collected is less than in the summer, and will provide a pre-heat to the bottom of the cylinder which can then be topped up via the current heating system in place. i.e. gas or an immersion heater.
For the average home 2-3 Flat Plate Collectors or around 1m³ of Evacuated Tubes would be a sufficient installation to provide the majority of the hot water for a 3-4 bedroom, 2 bathroom property. This means a solar thermal system is easy to accommodate even on smaller homes and or small available roof space where perhaps solar PV wasn’t possible. As with Solar PV, Solar Thermal panels will normally be considered Permitted Development for both Domestic and Commercial properties.
Storing the Solar Heat
The sun is not always shining when you want hot water, so storage plays a vital role in a solar thermal system. Generally, the heat is stored in water. Water storage can take many different forms. A Solar Thermal system is a closed-loop sealed system. This means that the fluid that passes through the solar collector never actually touches the water that is used throughout the home. The fluid is silently pumped through the closed system, heated by the sun’s energy in the solar collectors, then passes through a heating coil in the storage cylinder. This transfers the heat contained in the fluid to the water in the storage tank, and the cold fluid is then pumped back to the solar collector.
The rate of the pump is intelligently managed by the controller. This reacts to the temperature of the fluid in the solar collectors and the temperature of the water at different positions in the storage tank to determine the optimal flow rate to maximise energy savings.
The ideal storage tank will have a twin coil heating system. Ideally, your cylinder will be enlarged, a tall and thin cylinder with a solar coil at the bottom of it. Solar coils are different to traditional boiler coils as they have a larger surface area. The larger surface area of the coil in a solar cylinder means that the heat transfer is more efficient, and there is more opportunity for the heat from the solar to pass to the water in the cylinder. This in turn means that because the solar fluid can transfer more of its heat into the water in the cylinder, when it returns to the solar collector it will have a larger capacity to absorb heat.
In a twin coil cylinder the lower coil is heated from the solar collector, and the upper coil is heated by your conventional boiler. As hot waster rises this means that the water is heated as much as possible by the solar collector and then topped up as required, by your conventional boiler. This allows the maximum possible contribution from solar energy even during the shorter days of winter.
Although the cylinder is larger than the hot water requirements of the household, a twin coil cylinder will allow your water to be heated throughout by the solar; a free energy source. On good sunny days, when you have produced surplus hot water, you can store it for days when the solar gain is not as good.