Solar updraft towers are tall structures that generate electricity using the power of the sun. The towers consist of a central core enclosed by a spacious greenhouse-like structure. Inside the greenhouse, the warm air rises through the central core, creating uplift for the tower. Electricity is generated by the rising air that spins the turbines at the top of the tower.
Various external factors can impact the performance of solar updraft towers, such as wind speed and direction, air density, and the availability of sunlight. To improve the greenhouse’s performance, the air inside can be heated using mirrors before it enters the tower. Additionally, a heat storage system can be used to store and utilize heat during periods without sunlight.
Solar updraft towers have a lower power conversion rate compared to parabolic troughs and power towers in the solar thermal collectors. A 100-megawatt power plant needs a 1,000-meter tower and a greenhouse with an area of 20 square kilometers, according to model calculations. This power station of this magnitude has the capacity to supply electricity to approximately 100,000 typical households. Additionally, it has the potential to reduce carbon dioxide emissions by over 450,000 tons annually.
Working Principle of Solar Updraft Tower
There are basically 2 things on which this tower relies: principles of convection and solar energy. Convection refers to the active transfer of heat, allowing it to effortlessly move from one location to another. Warm air rises while cooler air sinks. By utilizing the sun’s energy, the solar updraft tower effectively harnesses this natural process of convection to heat the air within the tower. As the warm air ascends through the central core of the tower, it powers the turbines located at the top, effectively producing electricity.
Solar updraft towers are built to be very tall in order to ensure that the ascending air attains the optimal velocity required to effectively drive the turbines.
Also See: What is Meant by Solar Cooling?
Benefits of Solar Updraft Tower
Here is a list of benefits drawn from solar updraft towers.
- They generate electricity without any emission of pollutants or greenhouse gases, making them an attractive option.
- Since they do not rely on weather conditions, solar updraft towers give a stable power supply.
- These towers can also help in removing CO2 from the atmosphere by growing plants in their greenhouse-like structure. These plants can absorb carbon dioxide.
Solar updraft towers have only one drawback which is their high initial capital cost. Yes, they are quite expensive to build, resulting in a high initial investment in materials and land.
Also See: What is a Solar Thermal Collector?