Using Solar Thermal in Radiant Heating Systems
Up until a few years ago, solar energy was not very popular, given that high installation costs made it economically inefficient. However, the advancement of solar technology as well as rising energy prices, combined with special tax credits, are putting the industry of harvesting energy from the sun back on the map, making it affordable and profitable for many home owners. While solar is the type of energy that is vastly known to be used directly as its being harvested, it can also be stored for later use by using the Solar Thermal method.
Solar Thermal is a process of using the sun to heat a thermal mass, which is a solid or liquid material (such as water, concrete, and air) that can absorb, collect and store solar energy for subsequent use.
When it comes to using solar energy for radiant heating, water is considered to be a very efficient thermal mass. It can be moved with ease, it’s abundant, and can store a lot of heat. Aside from the obvious environmental benefits of utilizing green technology, solar thermal, systems that utilize a hydronic thermal mass significantly reduce expenses associated with operating a radiant heating system.
The basic component of any solar thermal system is a solar collector – a device that is used to intake the actual heat from the sun. While there are various types and designs of solar collectors, a flat plate collector is one of most basic and least expensive.
A flat plate collector consists of an aluminum sheet covered with black chrome (to help absorb heat), pipes that carry water, and insulation to make sure that the heat doesn’t escape. In order to save money on materials, many home owners build their own collectors using PEX tubing instead of copper. Some experts are being cautious about such practice, since PEX tubing’s life span is drastically reduced when it’s exposed to the sun. The ability of PEX to withstand extremely high temperatures that are produced by the sun is also questioned. During installation, special attention should be given when mounting a collector, as the degree at which it’s positioned has a huge effect on its efficiency.
When water is used as a thermal mass, it is stored in an insulated tank and is supplied to the system the same way as if it was a boiler. Considering that the solar heat varies in temperature, a mixing device is often used to maintain the required temperature. Houses that have solar thermal system also have a regular boiler, to be used when solar heat is not available.
It should be noted that the solar energy industry is still largely unregulated with few accepted standards and guidelines available.
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