System and component modelling of a low temperature solar thermal energy conversion cycle

2013 ◽  
Vol 24 (4) ◽  
pp. 51-62
Author(s):  
Shadreck M. Situmbeko ◽  
Freddie L. Inambao
Keyword(s):  
Low Temperature ◽  
Solar Energy ◽  
Thermal Energy ◽  
Electrical Power ◽  
Solar Thermal ◽  
Working Fluid ◽  
Small Scale ◽  
Solar Thermal Energy ◽  
Solar Field ◽  
Conversion Technology

Solar thermal energy (STE) technology refers to the conversion of solar energy to readily usable energy forms. The most important component of a STE technology is the collectors; these absorb the shorter wavelength solar energy (400-700nm) and convert it into usable, longer wavelength (about 10 times as long) heat energy. Depending on the quality (temperature and intensity) of the resulting thermal energy, further conversions to other energy forms such as electrical power may follow. Currently some high temperature STE technologies for electricity production have attained technical maturity; technologies such as parabolic dish (commercially available), parabolic trough and power tower are only hindered by unfavourable market factors including high maintenance and operating costs. Low temperature STEs have so far been restricted to water and space heating; however, owing to their lower running costs and almost maintenance free operation, although operating at lower efficiencies, may hold a key to future wider usage of solar energy. Low temperature STE conversion technology typically uses flat plate and low concentrating collectors such as parabolic troughs to harness solar energy for conversion to mechanical and/or electrical energy. These collector systems are relatively cheaper, simpler in construction and easier to operate due to the absence of complex solar tracking equipment. Low temperature STEs operate within temperatures ranges below 300oC. This research work is geared towards developing feasible low temperature STE conversion technology for electrical power generation. Preliminary small-scale concept plants have been designed at 500Wp and 10KWp. Mathematical models of the plant systems have been developed and simulated on the EES (Engineering Equation Solver) platform. Fourteen candidate working fluids and three cycle configurations have been analysed with the models. The analyses included a logic model selector through which an optimal conversion cycle configuration and working fluid mix was established. This was followed by detailed plant component modelling; the detailed component model for the solar field was completed and was based on 2-dimensional segmented thermal network, heat transfer and thermo fluid dynamics analyses. Input data such as solar insolation, ambient temperature and wind speed were obtained from the national meteorology databases. Detailed models of the other cycle components are to follow in next stage of the research. This paper presents findings of the system and solar field component.

Micro Solar Thermal Collector Glazing for Enhanced Thermal Energy Harvesting

2012 ◽  
Author(s):  
E. Ogbonnaya ◽  
L. Weiss
Keyword(s):  
Solar Energy ◽  
Thermal Energy ◽  
Alternative Energy ◽  
Capture Efficiency ◽  
Solar Thermal ◽  
Small Scale ◽  
Collector Plate ◽  
Research Areas ◽  
Area Of Interest ◽  
Solar Thermal Collector

Increasing focus on alternative energy sources has produced significant progress across a wide variety of research areas. One particular area of interest has been solar energy. This has been true on both large and small-scale applications. Research in this paper presents investigations into a small-scale solar thermal collector. This approach is divergent from traditional micro solar photovoltaic devices, relying on transforming incoming solar energy to heat for use by devices like thermoelectrics. The Solar Thermal Collector (STC) is constructed using a copper collector plate with electroplated tin-nickel selective coating atop the collector surface. Further, a unique top piece is added to trap thermal energy and reduce convective, conductive, and radiative losses to the surrounding environment. Results show a capture efficiency of 92% for a collector plate alone when exposed to a 1000 W/m2 simulated solar source. The addition of the top “glazing” piece improves capture efficiency to 97%. Future work will integrate these unique devices with thermoelectric generators for electric power production. This will yield a fully autonomous system, capable of powering small sensors or other devices in remote locations or supplementing existing devices with renewable energy.

scholarly journals Energy Analysis of a Novel Ejector-Compressor Cooling Cycle Driven by Electricity and Heat (Waste Heat or Solar Energy)

2020 ◽  
Vol 12 (19) ◽  
pp. 8178
Author(s):  
Fahid Riaz ◽  
Kah Hoe Tan ◽  
Muhammad Farooq ◽  
Muhammad Imran ◽  
Poh Seng Lee
Keyword(s):  
Low Temperature ◽  
Thermal Energy ◽  
Waste Heat ◽  
Solar Thermal ◽  
Coefficient Of Performance ◽  
Condensation Temperature ◽  
Low Grade ◽  
Solar Thermal Energy ◽  
Temperature Heat ◽  
Vapour Compression

Low-grade heat is abundantly available as solar thermal energy and as industrial waste heat. Non concentrating solar collectors can provide heat with temperatures 75–100 °C. In this paper, a new system is proposed and analyzed which enhances the electrical coefficient of performance (COP) of vapour compression cycle (VCC) by incorporating low-temperature heat-driven ejectors. This novel system, ejector enhanced vapour compression refrigeration cycle (EEVCRC), significantly increases the electrical COP of the system while utilizing abundantly available low-temperature solar or waste heat (below 100 °C). This system uses two ejectors in an innovative way such that the higher-pressure ejector is used at the downstream of the electrically driven compressor to help reduce the delivery pressure for the electrical compressor. The lower pressure ejector is used to reduce the quality of wet vapour at the entrance of the evaporator. This system has been modelled in Engineering Equation Solver (EES) and its performance is theoretically compared with conventional VCC, enhanced ejector refrigeration system (EERS), and ejection-compression system (ECS). The proposed EEVCRC gives better electrical COP as compared to all the three systems. The parametric study has been conducted and it is found that the COP of the proposed system increases exponentially at lower condensation temperature and higher evaporator temperature. At 50 °C condenser temperature, the electrical COP of EEVCRC is 50% higher than conventional VCC while at 35 °C, the electrical COP of EEVCRC is 90% higher than conventional VCC. For the higher temperature heat source, and hence the higher generator temperatures, the electrical COP of EEVCRC increases linearly while there is no increase in the electrical COP for ECS. The better global COP indicates that a small solar collector will be needed if this system is driven by solar thermal energy. It is found that by using the second ejector at the upstream of the electrical compressor, the electrical COP is increased by 49.2% as compared to a single ejector system.

Experimental investigation of methanol decomposition with mid- and low-temperature solar thermal energy

2010 ◽  
Vol 35 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Jun Sui ◽  
Qibin Liu ◽  
Jianguo Dang ◽  
Dong Guo ◽  
Hongguang Jin ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Low Temperature ◽  
Thermal Energy ◽  
Methanol Decomposition ◽  
Solar Thermal ◽  
Solar Thermal Energy

Pengujian Alat Pengering Surya Sederhana dan Modifikasi Menjadi Alat Pengering Hybrid

2018 ◽  
Vol 3 (3) ◽  
Author(s):  
Muhammad Irvan ◽  
Dewi Sri Jayanti ◽  
Raida Agustina
Keyword(s):  
Solar Energy ◽  
Thermal Energy ◽  
Biomass Energy ◽  
Solar Thermal ◽  
Solar Irradiation ◽  
Biomass Combustion ◽  
Energy Sources ◽  
Solar Thermal Energy ◽  
Green Beans ◽  
Average Temperature

Abstrak.  Pengering hybrid merupakan pengering yang menggunakan dua atau lebih sumber energi untuk proses penguapan air. Tujuan dari penelitian ini adalah memodifikasi alat pengering surya sederhana menjadi alat pengering hybrid dengan tambahan energi panas dari pembakaran tempurung kelapa untuk melakukan uji pengeringan pada kacang hijau. Distribusi suhu rata-rata pada alat pengering hybrid pengeringan kacang hijau menggunakan energi panas matahari, kombinasi dan biomassa masing-masing adalah 49oC,50oC dan 35oC dengan iradiasi matahari masing-masing menggunakan energi panas matahari dan kombinasi adalah 360,47W/m2 dan 362,79W/m2. Kelembaban relatif pada alat pengering hybrid saat pengeringan kacang hijau menggunakan energi panas matahari, kombinasi dan biomassa masing-masing adalah 44,69%, 45,69% dan 57,75%. Kecepatan udara pada alat pengering hybrid saat pengeringan kacang hijau menggunakan energi panas matahari, kombinasi dan biomassa masing-masing adalah 0,11 m/s , 0,1 m/s dan 0,08 m/s. Pengeringan kacang hijau menggunakan sumber panas dari energi matahari, sumber panas kombinasi energi matahari dengan pembakaran biomassa dan menggunakan energi pembakaran biomassa menghasilkan kadar air akhir biji kacang hijau masing-masing sebesar 8,42%, 8,27% dan 10,75%. Besarnya energi biomassa yang dihasilkan saat pengering selama 10 jam adalah 272,142 MJ. Besarnya energi matahari saat pengeringan kacang hijau menggunakan sumber energi matahari dan sumber panas kombinasi energi matahari dengan pembakaran biomassa adalah 3,22 MJ dan 3,14 MJ.Testing of Simple and Modified Solar Dryers Become a Hybrid Dryer ToolAbstract. A hybrid dryer is a dryer that uses two or more sources of energy for the evaporation process of water. The purpose of this study is to modify the simple solar drying tool into a hybrid drying tool with additional heat energy from coconut shell combustion to test drying on green beans. The average temperature distribution of green peanut drying dryers using solar thermal energy, combination and biomass are respectively 49oC, 50oC and 35oC with solar irradiation each using solar thermal energy and the combination is 360,47W/m2 and                362, 79   W/m2. The relative humidity in the hybrid drier when drying green beans using solar thermal energy, combination and biomass are 44.69%, 45.69% and 57.75%, respectively. The air velocity in the hybrid drier when drying green beans using solar thermal energy, combination and biomass are 0.11 m/s, 0.1 m/s and       0.08 m/s respectively. Drying of green beans using a source of heat from solar energy, a combination of solar energy sources with biomass combustion and using biomass combustion energy to produce the final content of green beans seeds by 8.42%, 8.27% and 10.75% respectively. The amount of biomass energy produced during drying for 10 hours is 272,142 MJ. The amount of solar energy during drying of green beans using solar energy sources and the combined heat source of solar energy with biomass burning is 3.22 MJ and 3.14 MJ.

scholarly journals Application of Solar Thermal Energy for Medium Temperature Heating in Automobile Industry

2017 ◽  
Vol 7 (2 (S)) ◽  
pp. 19
Author(s):  
Anagha Pathak ◽  
Kiran Deshpande ◽  
Sandesh Jadkar
Keyword(s):  
Solar Energy ◽  
Thermal Energy ◽  
Automobile Industry ◽  
Storage Tank ◽  
Fossil Fuel ◽  
Heating System ◽  
Hot Water ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Medium Temperature

There is a huge potential to deploy solar thermal energy in process heat applications in industrial sectors. Around 50 % of industrial heat demand is less than 250 °C which can be addressed through solar energy. The heat energy requirement of industries like automobile, auto ancillary, metal processing, food and beverages, textile, chemical, pharmaceuticals, paper and pulp, hospitality, and educational institutes etc. can be partially met with solar hybridization based solutions. The automobile industry is one of the large consumers of fossil fuel energy in the world. The automobile industry is major economic growth driver of India and has its 60 % fuel dependence on electricity and remaining on oil based products. With abundant area available on roof top, and need for medium temperature operation makes this sector most suitable for substitution of fossil fuel with renewable solar energy. Auto sector has requirement of heat in the temperature range of 80-140 oC or steam up to 2 bar pressure for various processes like component washing, degreasing, drying, boiler feed water preheating, LPG vaporization and cooling. This paper discusses use of solar energy through seamless integration with existing heat source for a few processes involved in automobile industries. Integration of the concentrated solar thermal technology (CST) with the existing heating system is discussed with a case study for commonly used processes in auto industry such as component washing, degreasing and phosphating. The present study is undertaken in a leading automobile plant in India. Component cleaning, degreasing and phosphating are important processes which are carried out in multiple water tanks of varying temperatures. Temperatures of tanks are maintained by electrical heaters which consumes substantial amount of electricity. Non-imaging solar collectors, also known as compound parabolic concentrators (CPC) are used for generation of hot water at required process temperature. The CPC are non-tracking collectors which concentrate diffuse and beam radiation to generate hot water at required temperature. The solar heat generation plant consists of CPC collectors, circulation pump and water storage tank with controls. The heat gained by solar collectors is transferred through the storage tank to the process. An electric heater is switched on automatically when the desired temperature cannot be reached during lower radiation level or during non-sunny hours/days. This solar heating system is designed with CPC collectors that generate process heating water as high as 90OC. It also seamlessly integrates with the existing system without compromising on its reliability, while reducing electricity consumption drastically. The system is commissioned in April, 2013 and since then it has saved ~ 1,75,000 units of electricity/year and in turn 164 MT of emission of CO2 annually.

scholarly journals Tuning the photochemical properties of the fulvalene-tetracarbonyl-diruthenium system

2016 ◽  
Vol 45 (21) ◽  
pp. 8740-8744 ◽  
Author(s):  
Anders Lennartson ◽  
Angelica Lundin ◽  
Karl Börjesson ◽  
Victor Gray ◽  
Kasper Moth-Poulsen
Keyword(s):  
Energy Storage ◽  
Solar Energy ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Chemical Energy ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
System P ◽  
Photochemical Properties

In a Molecular Solar–Thermal Energy Storage (MOST) system, solar energy is converted to chemical energy using a compound that undergoes reversible endothermic photoisomerization.

Preheating Metal Scrap in Foundries Using Solar Thermal Energy

2015 ◽  
Vol 813-814 ◽  
pp. 760-767 ◽  
Author(s):  
J. Selvaraj ◽  
Chandra C. Jawahar ◽  
Khushal A. Bhatija ◽  
Saalai Thenagan
Keyword(s):  
Solar Energy ◽  
Energy Conservation ◽  
Greenhouse Gases ◽  
Environmental Protection ◽  
Thermal Energy ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Metal Scrap ◽  
Parabolic Trough ◽  
Preheating Temperature

The present scenario of energy conservation has witnessed many innovative and eco-friendly techniques and one such area where there is a necessity to conserve energy is foundries. Foundries also pollute the atmosphere with greenhouse gases contributing to 296143037.6 metric tons annually. The proposed technique in this paper aims at reducing the energy utilized in melting the scrap material at foundries by solar thermal energy. In the methodology proposed, solar energy is concentrated onto the scrap placed on a receiving platform using a parabolic trough and heats it up so that the heated scrap takes lesser energy to melt. The experiments resulted in preheating temperature of 100 °C when placed on a receiving platform and 110°C when copper shots are used to conduct heat from receiver to the scrap. This translates to energy conservation of 6%. This eco-friendly technique when adopted can result in substantial savings in consumption and environmental protection.

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