A review of solar thermal technologies☆
Introduction
Of all the renewable sources of energy available, solar thermal energy is the most abundant one and is available in both direct as well as indirect forms. The Sun emits energy at a rate of 3.8 × 1023 kW, of which, approximately 1.8 × 1014 kW is intercepted by the earth, which is located about 150 million km from the sun. About 60% of this amount or 1.08 × 1014 reaches the surface of the earth. The rest is reflected back into space and absorbed by the atmosphere. About 0.1% of this energy, when converted at an efficiency of 10% would generate four times the world's total generating capacity of about 3000 GW. It is also worth noting that the total annual solar radiation falling on the earth is more than 7500 times the world's total annual primary energy consumption of 450 EJ. The annual solar radiation reaching the earth's surface, approximately 3,400,000 EJ, is an order of magnitude greater than all the estimated (discovered and undiscovered) non-renewable energy resources, including fossil fuels and nuclear. However, 80% of the present worldwide energy used is based on fossil fuels. Risks associated with their use are that they are all potentially vulnerable to adverse weather conditions or human acts. World demand for fossil fuels (starting with oil) is expected to exceed annual production, probably within the next two decades. International economic and political crisis and conflicts can also be initiated by shortages of oil or gas. Moreover, burning fossil fuels release harmful emissions such as carbon dioxide, nitrogen oxides, aerosols, etc. which affect the local, regional and global environment.
Section snippets
Study
Chang et al. studied the solar irradiation patterns for the performance testing of thermosyphon solar water heaters and concluded that a distribution factor Ri and its criterion have to be introduced into the CNS test standard to provide reliable test results for solar hot water heaters [1]. Mathioulakis and Belessiotis investigated the performance of a new solar hot water system with an integrated heat-pipe and compared the proposed theoretical model of the collector with the experimental
Study
Schwarzer and Vieira da Silva presented the experimental procedures to be used to calculate the parameters which determine the thermal performance of solar cookers and also suggested a simplified procedure based on energy balance equations for the design of solar cookers [41]. Ekechukwu and Ugwuoke presented the design philosophy, construction and measured performances of a plane-reflector augmented box-type solar-energy cooker which recorded a significant improvement in performance with the
Study
Karsli made a comparative study of four types of air heating flat plate solar collectors: a finned collector with an angle of 75°, a finned collector with an angle of 70°, a collector with tubes and a base collector. He concluded that their efficiency depends significantly on the solar radiation and the surface geometry of the collectors and also that at higher reduced temperature parameter, the overall loss is lower [84]. Mahaprata and Imre conducted a parameter sensitivity analysis on a
Study
Karakilcik and Dincer studied both energetic and exergetic performances of a solar pond through efficiency analysis and developed exergy efficiencies for each zone of the solar pond through exergy balance equations [103]. Tamimi and Rawajfeh analyzed the thermal performance of evaporators and their model developed on lumped basis indicates that the efficiency of any solar evaporator is limited by the optical absorptivity of the saline water [104]. Velmurugan and Srithar reviewed various designs
Study
He et al. proposed the solar cooling strategies for tackling long, hot and humid summer which consisted of a multi-functional solar system and a method for indoor ventilation; the design included double walls and a triple roof in order to remove heat by ventilation of the building envelope [121]. Kischkoweit-Lopin studied a huge number of different daylighting systems that allow new and optimized ways of daylight utilization with the consideration that the different systems have to be used in
Study
Grossman describes the current trends in solar powered air-conditioning systems in which he had substantiated that double and triple effect chillers had better COP than the single effect chillers while using LiBr/water as the working fluid and also highlighted the performance of open cycle absorption system and the need to replace it with closed cycle sorption systems [134]. Elsafty and Al-Daini made an economical comparison of solar powered single, double effect vapor absorption
Study
Zhou et al. carried out simulation studies to investigate the performance of a pilot scale solar chimney power plant for different solar intensities by varying collector area and chimney height and the simulated results closely agree with the measured values [148]. von Backstrom et al. investigated the turbine characteristics by developing analytical equations in terms of turbine flow, load coefficient and degree of reaction and their influence on turbine efficiency and proved that if applied
Study
von Backstörm and Fluri conducted a study and developed two analyses for finding the optimal ratio of turbine pressure drop to available pressure drop in a solar chimney power plant for maximum fluid power [155]. Segal and Epstein optimized the important components of a solar central receiver power plant like receiver, heliostat field and power block thus maximizing their efficiency and suggested that beyond a certain limit of the operating temperature the overall system efficiency decreases
Study
Porta et al. found that the overall thermal inertia effects can be adequately represented by a single non-dimensional quantity referred as thermal inertia slenderness ratio. Simulation of the calibrated mathematical model illustrates the influence of thermal inertia on performance [173]. Tiwari et al. reviewed the works on solar distillation, its present status and future perspective and also classified the distillation units [174]. Tzen and Morris presented technologies about renewable energy
Conclusion
A detailed literature survey of major solar thermal technologies comprising of solar water heaters, solar cookers, solar driers, solar ponds, solar architecture, solar conditioning, solar chimneys, solar power plants and solar stills was performed. The review gives a brief overview of the developments in each of these key areas of technology in view to either raise the performance of the presently used system or to build a new system which employs a great deal of innovation and gives better
References (185)
- et al.
A criterion study of solar irradiation patterns for the performance testing of thermosyphon solar water heaters
Solar Energy
(2002) - et al.
A new heat-pipe type solar domestic hot water system
Solar Energy
(2002) - et al.
A proposed modified efficiency for thermosyphon solar heating systems
Solar Energy
(2004) - et al.
An experimental study of two-phase closed thermosyphons for compact solar domestic hot-water systems
Solar Energy
(2004) - et al.
Analysis of horizontal mantle heat exchangers in solarwater heating systems
Solar Energy
(1998) - et al.
Development of a new solar thermal engine system for circulating water for aeration
Solar Energy
(2005) - et al.
Energy savings for solar heating systems
Solar Energy
(2006) - et al.
Experimental investigation of a two-phase closed thermosyphon solar water heater
Solar Energy
(2005) - et al.
Experimental study of temperature stratification in an integrated collector-storage solar water heater with two horizontal tanks
Solar Energy
(2006) - et al.
Feasibility study of a district energy system with seasonal water thermal storage
Solar Energy
(2000)
Heat-pipe enhanced solar-assisted heat pump water heater
Solar Energy
Mantle heat exchangers for horizontal tank thermosyphon solar water heaters
Solar Energy
Modelling and performance of a copolymer solar water heating collector
Solar Energy
Net energy analysis of solar and conventional domestic hot water systems in Melbourne, Australia
Solar Energy
Numerical study of flow and heat transfer characteristics in hot water stores
Solar Energy
Performance evaluation of photovoltaic–thermosyphon system for subtropical climate application
Solar Energy
Smart solar tanks for small solar domestic hot water systems
Solar Energy
Solar heat pump drying and water heating in the tropics
Solar Energy
Solar heat pump systems for domestic hot water
Solar Energy
Test standards for thermosyphon-type solar domestic hot water system: review and experimental evaluation
Solar Energy
The performance of a cylindrical solar water heater
Renewable Energy
The recycle effect on the collector efficiency improvement of double-pass sheet-and-tube solar water heaters with external recycle
Renewable Energy
Thermal performances of the active and passive water heating systems based on annual operation
Solar Energy
Water-in-glass evacuated tube solar water heaters
Solar Energy
Analytical approach of thermosyphon solar domestic hot water system performance
Solar Energy
Application of the genetic algorithm for optimisation of large solar hot water systems
Solar Energy
Assessing solar hot water system performance with GIS
Solar Energy
Characteristics of vertical mantle heat exchangers for solar water heaters
Solar Energy
Collector cum storage solar water heaters with and without transparent insulation material
Solar Energy
Methodology for estimation of potential for solar water heating in a target area
Solar Energy
Modeling of solar domestic water heating systems using artificial neural networks
Solar Energy
Optimisation of minimum backup solar water heating system
Solar Energy
Performance analysis of a solar-assisted heat pump water heater
Solar Energy
Rate of heat transfer in polypropylene tubes in solar water heaters
Solar Energy
Simulation of an unglazed collector system for domestic hot water and space heating and cooling
Solar Energy
The annual number of days that solar heated water satisfies a specified demand temperature
Solar Energy
Thermosiphon solar domestic water heating systems: longterm performance prediction using artificial neural networks
Solar Energy
Validation of a computer model for solar assisted district heating systems with seasonal hot water heat store
Solar Energy
Industrial solar hot water system and its performance
Solar Energy
Characterisation and design methods of solar cookers
Solar Energy
Design and measured performance of a plane reflector augmented box-type solar-energy cooker
Renewable Energy
Efficient orientation impacts of box-type solar cooker on the cooker performance
Solar Energy
Experimental investigation of a box type solar cooker employing a non-tracking concentrator
Energy Conversion and Management
Experimental study of a double exposure solar cooker with finned cooking vessel
Solar Energy
PCM storage for solar DHW: an unfulfilled promise?
Solar Energy
Performance study of solar cooker with modified utensil
Renewable Energy
Prediction and experimental verification of performance of box type solar cooker. Part II. Cooking vessel with depressed lid
Energy Conversion and Management
Prediction and experimental verification of performance of box type solar cooker. Part I. Cooking vessel with central cylindrical cavity
Energy Conversion and Management
Solar cooker acceptance in south africa: results of a comparative field-test
Solar Energy
Solar field control for desalination plants
Solar Energy
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Source: Survey of Energy Resources 2007, World Energy Council.