Sensible heat storage is widely used in solar thermal power plants and heating systems due to its simplicity, cost-effectiveness, and applicability to a variety of scenarios. Let's explore the applications of sensible heat storage in both solar thermal power plants and heating systems:
Applications in Solar Thermal Power Plants:
1. Parabolic Trough Power Plants: Parabolic trough solar thermal power plants use curved mirrors to concentrate sunlight onto a receiver tube running along the focal line of the trough. The receiver tube contains a heat transfer fluid (HTF), usually synthetic oil, which absorbs the concentrated sunlight and gets heated. The heated HTF then transfers the thermal energy to a storage medium, typically a tank of molten salt or a mixture of rocks and sand.
- Sensible Heat Storage: The heated HTF transfers its sensible heat to the storage medium during the day when the sun is shining and energy demand is low. Later, during the evening or when the sun is not available, the stored thermal energy is used to generate steam and produce electricity using a steam turbine.
2. Solar Tower Power Plants: Solar tower, or central receiver, power plants use an array of mirrors, called heliostats, to concentrate sunlight onto a central receiver located on top of a tower. The receiver absorbs the concentrated sunlight and heats a working fluid, which can be water, molten salt, or air.
- Sensible Heat Storage: Similar to parabolic trough power plants, solar tower plants can use sensible heat storage with a medium like molten salt. The molten salt is heated during sunny periods and then used to produce steam and generate electricity during periods of low solar radiation.
Applications in Solar Heating Systems:
1. Solar Water Heating Systems: Solar water heating systems are used to heat domestic, commercial, and industrial water using solar energy. These systems typically consist of flat-plate or evacuated tube collectors, a heat exchanger, and a storage tank.
- Sensible Heat Storage: Sensible heat storage is commonly employed in solar water heating systems using a water storage tank. During sunny periods, the solar collectors heat the water in the tank directly, which is then available for use during cloudy or nighttime hours.
2. Solar Space Heating Systems: Solar space heating systems use solar energy to provide space heating for buildings during colder periods. These systems often involve using solar collectors to heat air or a heat transfer fluid, which is then distributed for space heating.
- Sensible Heat Storage: Sensible heat storage can be incorporated into solar space heating systems using thermal mass in the building structure. Materials like concrete floors or walls act as thermal energy storage, absorbing heat during the day and releasing it gradually to warm the building during the night.
3. Solar Greenhouses: Solar greenhouses utilize solar energy to maintain a controlled and warm environment for plant growth. Sensible heat storage, often in the form of water containers or rocks, can help regulate temperatures within the greenhouse, providing heat during the night or on cloudy days.
Overall, sensible heat storage plays a vital role in enhancing the effectiveness and reliability of solar thermal power plants and heating systems. It allows for the utilization of solar energy even when the sun is not shining, enabling a more continuous and stable energy supply.