Solar Thermal Energy Systems (0406420) Lecture Notes PDF

Solar Thermal Energy Systems 0406420 Prof. Ibrahim El-Sharkawy Sustainable and Renewable Energy Engineering Department Office: M9-210 Lectures: Monday, Wednesday 12:30 – 1:45 PM Office Hours: Monday, Wednesday 10:00 – 11:00 AM E-mail: i...

Solar Thermal Energy Systems 0406420 Prof. Ibrahim El-Sharkawy Sustainable and Renewable Energy Engineering Department Office: M9-210 Lectures: Monday, Wednesday 12:30 – 1:45 PM Office Hours: Monday, Wednesday 10:00 – 11:00 AM E-mail: [email protected] Fall 2024/2025  Chapter (3) Introduction to Solar Thermal Applications Contents: ❑ Types of Solar Collectors ❑ Collector designs ❑ Installation of solar collectors ❑ Components of solar collectors ❑ Applications of solar collectors August. October th 31th 4 Energy Systems Lecture Solar Thermal (2) (11) Fall 2024-2025  Solar Thermal Energy Working fluid Solar Radiation Solar Thermal Energy Solar collector Solar collector 3 August. 31 th Energy Systems Solar Thermal (3) Fall 2024-2025  CPC Types of Solar Collectors ETC FPC 1- Collector design and working fluid temperature LFR PTC PDR HFC August. th 31 Energy Systems 4 Solar Thermal (4) Fall 2024-2025 August. th 31 Energy Systems Solar Thermal (5) Fall 2024-2025 August. th 31 Energy Systems Solar Thermal (6) Fall 2024-2025 August. th 31 Energy Systems Solar Thermal (7) Fall 2024-2025  Solar thermal energy applications Low temperature installations T< 100 ºC Swimming pool heating (T ~25°C) Domestic hot water, DHW, (dwellings, gyms, schools, hotels...) T = 45-60°C Space heating (radiant floor T = 30-35°C, radiators T =70°C) Medium temperature installations T< 400 ºC (T > 90°C till T = 250°C) Industrial processes, desalination, sterilization, etc. Adsorption/Absorption cooling systems High temperature installations T > 400 º C (CSP),desalination,..... Radiant floor heating August. th 31 Energy Systems Solar Thermal (8) Fall 2024-2025  Types of Solar Collectors A. Passive systems 2- Classification by type of circulation B. Active systems Are natural circulation systems, due to buoyancy forces allowing water or A. Passive systems: heat-transfer fluid to move through the system without pumps. Advantages Disadvantages No electric components Require careful planning to optimize performance More reliable there is a poor control of over- heating. Easier to maintain For a better circulation, the hot water storage tank must be located above the collector level Possibly longer-lasting than active systems. August. th 31 Energy Systems Solar Thermal (9) Fall 2024-2025  Types of Solar Collectors A. Passive systems 2- Classification by type of circulation B. Active systems Installations with forced circulation, pumps are required for circulation of B. Active systems: the Heat transfer fluid HTF through the collectors. Advantages Disadvantages Integral Pumps or fan protection are requires against electricity and freezing, must be overheat controlled. control Heat is Are more delivered complex from the systems and in collector at general more What is the difference optimal rate. expensive. between fan and pump ?? August. th 31 Energy Systems Solar Thermal (10) Fall 2024-2025  Other Classifications 3- Depending on the level of concentration / efficiency: 4- Relative position respect to the sun low-to-medium temperature, non-concentrating, 30-50% Fixed surfaces medium and high temperature, concentrating, 50-75% One-axis tracking Two-axis tracking 5- Depending on the loop type 6- Depending on the number of covers 11 August. 31 th Energy Systems Solar Thermal (11) Fall 2024-2025 Collector designs transparent insulation materials (TIM) Components of solar collectors Installation of solar collectors Installation direction For northern hemisphere → Facing south For southern hemisphere → Facing north Tilted angle roughly equal to Local Latitude Applications of Low-to-medium temperature systems Natural circulation systems. Thermosyphons ❑Usually 2-3 m2 flat plate collector area and a 150 litre store are used for a family of four. The coverage of the house DHW load is about 50 %. ❑There is no need for circulations pumps, self-regulating system ❑They are compact, low maintenance, easy assembly ❑Low mass flow rate system, depending on the solar radiation August. th 31 Energy Systems Solar Thermal (14) Fall 2024-2025  Solar thermal DHW systems for single an multi-family homes They are suitable for both new-build and retrofit. The collector is installed on the roof and the hot water store is usually situated in the basement. The solar heated transfer fluid circulates through the hydraulic solar circuit with the help of a pump. About 4-6 m2 at plate collector area and a 300 litre store. August. th 31 Energy Systems Solar Thermal (15) Fall 2024-2025  Large solar thermal systems for large DHW consumers ❖ In multi-family buildings, hotels, hospitals, residential homes, Swimming pool, Industrial process heating, etc. with a high DHW demand ❖ These systems are usually forced circulation systems with the collector area on the roof and a central hot water store in the basement. ❖ A typical size is 0.5 to 1 m2 collector area per occupant and 50 litre hot water volume per m2 collector area. ❖ The larger the system the higher the hot water demand satisfied by the solar system August. th 31 Energy Systems Solar Thermal (16) Fall 2024-2025  Installations with forced circulation. Heating + DHW (combisystems) Solar heating systems for combined domestic hot water preparation and space heating These are mainly used in central Europe, especially in Germany, Austria, Switzerland and France 15 to 30 m2 at plate collector and a 1- 3 m3 hot water store Combisystem can contribute as much as 20-30% of the combined DHW and space heating requirement Solar combisystems generally consist five elements: a solar collector loop; a storage subsystem; a control subsystem; an auxiliary subsystem; and a heat distribution subsystem 17 The solar collector area supplying a combisystems will be typically 3times the area supplying a DHW systems alone August. th 31 Energy Systems Solar Thermal (17) Fall 2024-2025  Solar power Tower High temperature applications The most common application is for electricity production Large collector fields, concentrate beam radiation to obtain a high temperature fluid in order to produce electricity Different technologies are currently being used e.g. PTC, solar tower, linear Fresnel, parabolic dishes Parabolic Dish. The systems that concentrate the solar rays use mirrors or lenses to focus the light into a specific zone to produce high temperatures, this allow the system to be very efficient energy conversion, such as Parabolic Trough, solar tower, parabolic dish. August. th 31 Energy Systems Solar Thermal (18) Fall 2024-2025 Shams Solar Power Station