Solar Thermal Energy
Solar
thermal energy is a technology that harnesses energy from the sun
(solar energy) to generate heat, or thermal energy. Solar energy is
gathered through highly efficient receivers/collectors and moves through
a thermal liquid, which stores the heat (energy).
Solar thermal energy is different from photovoltaic, which convert solar energy directly into electricity. As new solar thermal technologies continue to move from the conceptual to application stage, the solar thermal industry is growing quickly, attracting involvement from big names in energy like Siemens, PG&E and large corporations like Google. This benefits consumers because as solar thermal technology advances, the price of providing this energy drops.
Solar thermal power currently leads the way as the most cost-effective solar technology in large-scale applications. The latest generation of solar thermal technology, concentrated solar power, used for the large-scale production of electricity, offers the promise of even larger scale environmental benefits. In its simplest form, a concentrated solar power plant consists of solar collectors (mirrors or parabolic dishes), that collect heat to transform water to steam, which in turn provides force to move electricity generating turbines. The environmental benefits are obvious. Emissions from steam generated electricity share little in common with their cousins, emissions from fossil-fueled generated electricity plants, the primary causes of air pollution such as smog, acid rain and climate change.
Solar water heating systems for industrial, commercial and residential use typically consist of solar receivers and a collector, which gathers the sun's heat and transfers it to water passing thought the plumbing system on its way to a hot water storage container. Solar water heating systems save money by reducing the electricity costs associated with traditional water heating. They are also environmentally friendly because saving electricity also means avoiding the pollutants associated with electricity production or burning natural gas.
Solar thermal energy is different from photovoltaic, which convert solar energy directly into electricity. As new solar thermal technologies continue to move from the conceptual to application stage, the solar thermal industry is growing quickly, attracting involvement from big names in energy like Siemens, PG&E and large corporations like Google. This benefits consumers because as solar thermal technology advances, the price of providing this energy drops.
Solar thermal power currently leads the way as the most cost-effective solar technology in large-scale applications. The latest generation of solar thermal technology, concentrated solar power, used for the large-scale production of electricity, offers the promise of even larger scale environmental benefits. In its simplest form, a concentrated solar power plant consists of solar collectors (mirrors or parabolic dishes), that collect heat to transform water to steam, which in turn provides force to move electricity generating turbines. The environmental benefits are obvious. Emissions from steam generated electricity share little in common with their cousins, emissions from fossil-fueled generated electricity plants, the primary causes of air pollution such as smog, acid rain and climate change.
Solar water heating systems for industrial, commercial and residential use typically consist of solar receivers and a collector, which gathers the sun's heat and transfers it to water passing thought the plumbing system on its way to a hot water storage container. Solar water heating systems save money by reducing the electricity costs associated with traditional water heating. They are also environmentally friendly because saving electricity also means avoiding the pollutants associated with electricity production or burning natural gas.
The Components
If you’ve ever left a cool beverage out on a sunny day, you understand how quickly the sun heats up liquids. A Solar Thermal, or Solar Hot Water system simply takes advantage of that effect to heat water for your home.
Solar Thermal systems use three main components: solar heat collector panels on your roof, a hot water storage tank in your basement, and Control Monitor that lets you monitor system performance.
Solar Thermal panels:
Solar Thermal tank:
Solar Thermal systems use three main components: solar heat collector panels on your roof, a hot water storage tank in your basement, and Control Monitor that lets you monitor system performance.
Solar Thermal panels:
- In a Solar Thermal system, the array of panels on your roof is relatively small, usually a pair of solar thermal panels can provide enough hot water for household of four or more.
- Inside the panels, a fluid called glycol passes through a series of tubes, heated by the sun’s energy. The glycol is pumped in a continuous closed-system loop to your basement where it reaches a solar thermal tank.
- There, a heat exchanger extracts the heat from the glycol to heat water. The water in the solar thermal tank can get quite hot, up to 160 degrees, and is ready for use.
Solar Thermal tank:
- A solar thermal tank looks remarkably like a conventional hot water tank, and we generally install it adjacent to your existing tank.
- The solar tank feeds into your existing tank, so instead of heating up the cold water that comes in from the water company, you consume water heated by the sun.
- There is no threat of running out of hot water, as even in the case of an extended period of consistently cloudy weather your traditional hot water tank will come on to cover supply.
- The most important benefit of this tank arrangement is significantly reduced utility bills for making hot water. A lesser considered benefit is that your traditional hot water tank only supplements the solar thermal system, so it is used far more infrequently and therefore lasts longer.
Collection Methods
There are currently two methods for solar thermal collection.
- The first is line focus collection.
- Line focus is less expensive, technically less difficult, but not as efficient as point focus. The basis for this technology is a parabola-shaped mirror, which rotates on a single axis throughout the day tracking the sun. The point of focus in a line focus mirror array can only reach temperatures around 300°C.
- The second is point focus
collection.
- Point focus, though initially costlier and technically more nuanced. The point focus technique requires a series of mirrors surrounding a central tower, also known as a power tower. The mirrors focus the sun's rays onto a point on the tower, which then transfers the heat into more usable energy.
A solar thermal collector is specifically designed and manufactured to collect heat; that is, to absorb sunlight radiation and convert it to heat. Although the term is commonly being applied to commercial & residential solar thermal collectors, it is also used to denote installations that are more complex.
- Solar thermal collectors are commonly segmented as low-temperature,
medium-temperature, or high-temperature receivers.
- High temperature receivers concentrates the sunlight using parabolic troughs and/or mirrors or lenses and are generally used for electric power production and large industrial processes.
- Medium-temperature collectors are also usually used for creating hot water for residential and commercial use.
- Low temperature collectors are generally used to heat swimming pools.
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