Solar Thermal Technology - The Emission-Free Method to Generate Steam and Power
Posted: Dec 27, 2018
Solar thermal technology is used to harness the energy from the sun’s rays for heating water and producing steam to generate electricity and for various other purposes. Solar thermal technology is different from solar photovoltaic panels which convert the sun’s radiation into electricity. It uses solar thermal concentrators to capture the heat of the sun and process it for use in various domestic, industrial and commercial activities. Solar thermal concentrators are generally installed on the roofs of buildings or in an open space. The steam generated using solar thermal technology can be utilized for running a steam turbine to generate electricity or for cooking purpose through custom-made vessels. The hot water thus produced can also be used for bathing and washing.
The major advantage of solar thermal technology is that it reduces deforestation and helps conserve non-renewable, carbon-intensive fuels.
Two primary types of solar thermal systems: Active and PassiveActive systems require devices like fans or pumps to circulate heated fluids or steam from a central heating arena. Passive systems are free of mechanical or moving components and depend on their design to capture heat.
Three types of collectors that are used in solar thermal system are:
Low-temperature collectors: These are generally made of unglazed surfaces and are used to heat water in swimming pools, the water used for bathing and washing or to heat the air inside a room.
Medium-temperature collectors: These are also generally made of flat plates and are used for heating water or air in residential or commercial spaces. For example, in a solar cooker, specially-shaped reflectors are used to focus the sun’s rays on a central cooking vessel.
High-temperature collectors: Here mirrors or lenses are used for generating temperatures up to 300-degree Celsius at 20 bar pressure. This temperature is sufficient for generating steam to run turbines in industries, and for electric power production.
The pros and cons of using solar thermal technology
Pros: • Sunlight which powers solar thermal devices is freely available and solar plants have a long life with very little maintenance cost. • Since this is a renewable and emission-free form of energy, its use reduces the dependence on fossil fuels and helps cutting down greenhouse gases. • It can be used for a number of domestic and commercial applications at a very low cost.
Cons: • Although solar energy is free, it is not consistently available at all times of the year and in all places. On cloudy or rainy days, it would be very difficult to cater to the energy needs of homes and factories using solar thermal technology. • Sunshine is not uniformly available throughout the day and is not a highly concentrated source. Hence, the types of equipment necessary to produce a reasonable amount of solar energy can require a large area, evoking land procurement concerns. • Many solar thermal power plants are located in remote areas such as deserts where the water necessary to generate steam and to run turbines for electricity production is generally inadequate. Besides this, the transmission of electricity over large distances is expensive and can involve huge transmission and distribution losses. This casts doubts on the viability of the technology. • Finally, it is no secret that the installation of solar thermal power plants requires huge upfront capital costs and this is a big disadvantage for start-ups.
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