HUSSAIN's Comments

However, the solar PV array convert 8 :15 % of the absorbed solar radiation to electricity, the rest dissipates as heat [1]. This motivates a heat and electricity cogeneration system, where heat is removed from the PV array, stored and used not only to provide process heat but also to heat industrial buildings. Since the heat production per square meter of solar PV array can be as much as four times greater than the electrical energy produced [2] so putting this heat to use improves the system total efficiency and cost effectiveness. A solar PV and Thermal (PV/T) cogeneration systems are expected to play a significant role in the prospective SHSIP. The long-term goal is to realize SHSIP that produce electrical as well as thermal power at sufficiently low cost.
Thereby, the recent study was undertaken to include proposed Grid connected Cogeneration Solar System (GCSS) targets the two dominating energy demands for dairy manufacturing plant [1]: low level thermal energy required in industrial processes and high level energy (electricity) to cover a significant fraction of the plant electricity demand. The study result shows that, the proposed GCSS offer some potential advantages over a conventional SHSIP design. For the case study [1] the annual Specific Rate of fossil Fuel Saving (SRFS) in electrical power grid amount 196.75 kg.fuel/year per square meter of the PhotoVoltaic /Thermal (PV/T) solar collector arrays as a result of 188.0 kW.hr/year.m2 electrical, and 815.96 kW.hr/year.m2 thermal , power generation.
[1] Hussain Alrobaei, 2007, Advanced Solar Heating System for Industrial Processes/ The Middle East Mechanical Engineering Conference (MEMEC 2007), November 4 : 7 , 2007 , Manama , Kingdom of Bahrain.
[2] Hussain Alrobaei, 2007, Performance and Effectiveness of Grid Connected Solar Systems
for Domestic Hot Water Heating and Brackish Water Desalination./The Energy Central Network/ ergycentral.com /centers. / knowledge / whitepapers.

Finding an inexpensive and reliable source of energy is a challenge in many developed and developing countries. On the demand side, industry is an enormous consumer of energy. Solar Heating System for Industrial Processes (SHSIP) as a renewable energy source can cover a significant fraction of the industrial heat. By replacing electric energy or fossil fuel use for industrial process heat, environmental carbon emissions associated with industrial process heat are reduced or eliminated. However, most systems have back-up energy source such as electricity or gas. The most significant current application areas of SHSIP are in the food and dairy industries, the textile and chemical industries. This is, above all, due to the low temperatures required for the main processes in these sectors: 40 °C to 85 °C [1], allowing the use of commercially available flat plate or vacuum tube solar collectors which are very efficient in this temperature range [1,2]. The Solar Collector Arrays (SCA) can be integrated either into industrial roofs, or installed on an available ground area. In addition, the fact that the roof of manufacturing plant provides a good alternative to limited land availability, installing the SCA on the roof prevents the roofs direct exposure to the solar radiation helping at the summer season in sunny regions the internal cooling process of the plant. At the same time the costs of solar PhotoVoltaic (PV) systems keep on reducing and as advances in Building Integration (BI) techniques continue to be made. There is growing interest in grid connected BIPV systems and the possibility of integration into the roof of industrial buildings is of great importance. The application of BIPV systems is particularly interesting because it demonstrates several advantages compared with conventional PV power plants. Moreover, on-site generation has the additional efficiency benefit of avoiding the transmission and distribution losses associated with centralized generation. Howe

Currently Concentrating Solar thermal Power (CSP) is a prime choice in developing an affordable, feasible, global energy source that can be a substitute for fossil fuels in the sun belts around the world. CSP technologies are the least-cost option for energy and water security in Middle East and North Africa (MENA). The main concepts used in CSP technologies are parabolic troughs, solar towers, or dish/engine systems, which vary according to the concentration devices, energy conversion methods, storage options and other design variables. Thanks to storage systems, the plant can keep working at a constant load. With high performance and low electricity production costs, the outlook for parabolic trough power plants is very good. Within the MENA-CSP study, Integrated Gas turbine Solar Power Plant (IGSPP) play the major role in the long-term energy supply, because with their capability of thermal energy storage and of solar/fossil hybrid operation can provide firm capacity and thus are a key element for grid stabilization and power security in such a well-balanced electricity mix. The IGSPP offers a number of potential advantages over conventional Solar thermal power plants and represents an innovative way to reduce cost and improve the overall solar-to-electric efficiency. Also, the IGSPP will allow for a flexible transition from the present Combined Cycle power Plants (CCP) based on fossil fuels to a future plants based to a large extend on solar energy . It is also important to note that, according to the World Bank, the expected evolution of total electricity costs is that they will drop to 8 to 7 € cents/kW.h in the medium term (100 MWe Rankine-cycle plant or 100 Mwe Integrated Solar CCP, both with storage) and to 5 € cents/kW.h in the long term (200 MWe Rankine-cycle plant with storage) for high insolation sites with an annual direct normal solar radiation of more than 2800 kW.h/m2.

Solar tower is one of the alternative technologies proposed as a device to economically generate electricity from solar energy or/and low temperature geothermal energy in large-scale. A well-balanced mix of renewable energy sources with fossil fuel backup can provide affordable power capacity on demand. The geographical location, climate, and local conditions are the most important factors that determine the possibilities of applying solar energy and other renewable and methods of energy conversion. From this standpoint the author proposes a new approach to prospective Solar Tower Power Plant (STPP). This approach includes the combining of the following grid connected technologies: Hybrid Geothermal / Solar Chimney Power Plant and Hybrid Geothermal / PV / Solar Chimney Power Plant
The novel proposed schemes offer a number of potential advantages and represents an innovative way to reduce cost, optimizing the consumption of fossil fuel, and minimizing the environmental impact [1]. They are based on thermal conversion, which allows hybrid operation with both solar heat and low temperature geothermal to continue generating electricity even when sunlight is not available. Attractive alternative is to use geothermal energy for electricity generation, because it is available around the clock and can be regulated according to the demand. Geothermal power generation could thus provide a major contribution to the basic supply of solar electricity. This is a major advantage since it enables operation according to the actual demand for electricity, without limitation to sunlight hours only and considerably improves STPP ability to compete with conventional power plants.
[1] Hussain Alrobaei, 2007, Hybrid Geothermal/Solar Energy Technology For Power Generation/ environmental-expert.com/resultarticlept.asp.

In recent years the idea of introducing PV energy into the electrical network has become quite popular. Grid-connected systems, such as PV in Buildings, also have a significant potential.At the same time the costs of solar PV systems keep on reducing and as advances in Building Integration (BI) techniques continue to be made there is growing interest in grid connected BIPV systems and the possibility of integration into the roof of residential buildings is of great importance. However, the solar PV array convert of 8: 15 % the absorbed solar radiation to electricity, the rest dissipates as heat. This motivates a heat and electricity cogeneration system, where heat is removed from the PV array, stored and used not only for domestic hot water heating but also can be used for low temperature space heating.Various concepts of combined PV-thermal collectors are possible.These concepts differ in their approach to obtain the maximum yield and it is not easy to say whether the yield of a complicated design will be substantially higher than the yield of a simpler one [1].
.[1] Hussain Alrobaei, 2007 , The Effectiveness of Combined Heat and Power Solar Water Heating Systems/ environmental-expert.com/resultarticlept.asp.

Current drastically increasing fuel prices and power shortages for summer daytime peaking power in southern Europe suggest that Concentrated Solar Power (CSP) systems will find their prime market segment in summer season on peaks.Any renewable energy supply strategy aiming to take over the major part of electricity supply in the decades to come has to consider CSP as this technology option is capable of contributing with reliable, dispatchable power, specifically for daytime-demand peaks.In addition to that Integrated Solar Combined Cycle power Plants (ISCCP) with their capability of thermal energy storage and of solar/fossil hybrid operation can provide firm capacity and thus are a key element for grid stabilization and power security in such a well-balanced electricity mix.The desired effect of integrating a Gas Turbine Unit (GTU) with a Solar parabolic trough Power Plant (SPP) is not just to add the power produced by the GTU to that produced by the SPP but indeed to augment the latter.Beside that, the increase in the output of solar collector arrays and, subsequently, in solar power generation, will also useful to offset the normal reduction in performance experienced by GTU during the summer season [1].
It is also important to note that, according to the World Bank, the expected evolution of total electricity costs is that they will drop to 8 to 7 € cents/kW.h in the medium term (100 MWe Rankine-cycle plant or 100 Mwe ISCCP, both with storage) and to 5 € cents/kW.h in the long term (200 MWe Rankine-cycle plant with storage) for high insolation sites with an annual direct normal solar radiation of more than 2800 kW.h/m2.
[1] Hussain Alrobaei,2006, Integrated Gas Turbine Solar Power Plant/ The
Energy Central Network/ nergycentral.com/centers/knowledge/whitepapers.

Current drastically increasing fuel prices and power shortages for summer daytime peaking power in southern Europe suggest that Concentrated Solar Power (CSP) systems will find their prime market segment in summer season on peaks. Here, power generation cost differences, compared to typically used gas turbine operation, are smallest. Any renewable energy supply strategy aiming to take over the major part of electricity supply in the decades to come has to consider CSP as this technology option is capable of contributing with reliable, dispatchable power, specifically for daytime-demand peaks. Moreover, southern Europe is not capable of generating all of its required reliable peaking power alone through its own renewable resources. Consequently, energy cooperation with its neighboring countries is mandatory and has already become day-by-day practice.

Wind, biomass and Concentrating Solar thermal Power (CSP) plants are already today competitive with fuel oil at 50 $/barrel, and heading for competitiveness with natural gas and coal. A major advantage of CSP plants is their capability for thermal energy storage and hybrid operation with fossil or bio-fuels, allowing them to provide firm power capacity on demand. Further, due to a higher solar irradiance, the cost of CSP is usually lower in the Middle East and North Africa (MENA) than in Europe. Therefore, there will be a significant market for producing solar electricity under the ideal meteorological conditions in the sunbelt countries of the MENA and transferring part of this electricity to Europe. As proposed recently by the Trans-Mediterranean Renewable Energy Cooperation, concentrating solar thermal power stations in MENA could be used for export electricity to Europe as well as for providing regional freshwater from combined thermal desalination of sea water [1,2]. The electricity produced in CSP plants can be used for domestic needs and export, as well as for additional desalination of sea water through reverse osmosis (RO), if required. The design of such combined solar power and desalination plants can be flexibly adapted to any required size and need. CSP plants can be designed from 5 MW to several 100 MW capacity [3]. Therefore, in the future European mix of energy sources for power generation, CSP can serve to cover base load, intermediate load or peaking load and even to compensate the fluctuations of PV and wind power.

1. Hussain Alrobaei , 2007, Novel Integrated Gas Turbine Solar Cogeneration Power Plant/DEC, Halkidiki, Greece ,22–25 April 2007.

2. Hussain Alrobaei , 2006 , Repowering and Modification of Grid Connected Reverse Osmosis Desalination Plants/CIERTA 2006 , Exposiciones y Congresos - Roquetas de Mar (Almería).
3. Hussain Alrobaei,2006, Integrated Gas Turbine Solar Power Plant/ The Energy Central Network/ energycentral.com/centers/knowledge/whitepapers.

Currently Photovoltaics is the right technology for decentralized utilization of solar energy, while the strength of Solar Thermal Power Plant (STPP) technology is centralized power generation. STPP technology is particularly efficient at higher solar radiation intensity. Therefore it offers very good options for development not only for the southwestern region of US, but also in many economically disadvantage region in the earth’s Sunbelt. Furthermore, Parabolic trough technology has know entered a phase of constant optimization .the operation coasts have dropped from originally 0.08 $/kW.hr to 0.03 $/kW.hr. By 2015 the power production cost will be comparable to those of medium load power plants using fossil fuels. STPP technology can provide the necessary amount of clean energy to achieve the targets for optimizing the consumption of fossil fuel in electrical power grid, minimizing the environmental impact, and climate stabilization. The waste heat of STPP can be used for seawater desalination as well as for electricity generation. Countries in North Africa and Middle East, which are outstanding locations for STPP technology, could improve their water supplies by this means [1,2,3].   1. Hussain Alrobaei , 2007, Novel Integrated Gas Turbine Solar Cogeneration Power Plant/DEC, Halkidiki, Greece ,22–25 April 2007.

 2. Hussain Alrobaei , 2006 , Repowering and Modification of Grid Connected Reverse Osmosis Desalination Plants/CIERTA 2006 , Exposiciones y Congresos - Roquetas de Mar (Almeria).

3. Hussain Alrobaei ,2002,  Study the Effectiveness of Hybrid Solar Multiple Effect Distillation Plants/  1^ST International Congress of Mechanics – Constantine ( ICM-C⁰² ), Department of Mechanical Engineering /     University of Constantine,Algeria, December 14: 16, 2002. 

The application of BI5   deg.ge -40 deg,to note that uilding-Integrated (BI) PV systems is particularly interesting because it demonstrates several advantages compared with conventional PV power plants. This application actually expands technological potential of PV systems even further, because in buildings, they can play more roles than solely producing electricity. Besides generating electricity integrated BIPV systems can also enhance a building’s beauty, visibility, and prestige. There are several ways to integrate PV into a building’s design : Roofing, Facades, Atriums, and Shade screens. PV shade screens provide a large area for generating electricity and also reduce solar heating in the summer, which cuts cooling loads and glare. Shade screens cost less than other BIPV systems because extra ventilation of the PV modules is not needed. They can be retrofitted onto existing buildings or integrated into a new building's design.It is also important to note that facades offer a large area for PV modules. Besides generating electricity PV facades must look appealing and protect the building from weather. They can be integrated with windows, daylighting, and shading schemes to provide multiple benefits. However, vertically oriented PV panels at the latitude angle from - 35 deg  to 35 deg. have much reduced electricity output compared to panels sloped toward the sun. The reduction is greatest in the summer when the sun is high in the sky; this is also when electricity is most valuable. To overcome this problem, facades can be sloped using a saw tooth design.

The application of Building Integrated (BI) PV systems is particularly interesting because it demonstrates several advantages compared with conventional PV power plants. Moreover, on-site generation has the additional efficiency benefit of avoiding the transmission and distribution losses associated with centralized generation. However, the solar PV array has a typical efficiency of 8 to 15 %. This means that the remaining 85 to 92 % of the energy is in principle available in the form of heat. The availability of heat together with electricity is a good chance for better design the system integration into the user overall energy demand scheme. Moreover, 5 putting this heat to use improves the system total efficiency and cost effectiveness [1]. Various concepts of combined PV/Thermal (PV/T) collectors are possible. The simplest design is similar to a solar thermal flat plate collector of which the black absorber is replaced by encapsulated solar cells. Heat is extracted from the solar PV/T array by a heat-transporting medium like water or air. These concepts differ in their approach to obtain the maximum yield and it is not easy to say whether the yield of a complicated design will be substantially higher than the yield of a simpler one. They strongly depend on the specific configuration of the collector (geometry, materials, etc. ) and on the running conditions (air or water air flow rates, temperatures, etc.) together with climatic conditions of operation.

The long-term goal is to realize GC Solar System (GCSS) that produce electrical as well as thermal energy at sufficiently low cost. This means that the  investment costs has to be lowered as much as possible. This can only be achieved by careful design, proper realization, optimization, standardization and mass production. In addition to this, PV/T building elements should also be designed in such a way that they meet architectural requirements and technical standards and look attractive to consumers as well. From this standpoint the recent study [1] was undertaken to include proposed GCSS targets the two dominating energy demands in residential buildings: low level energy for water heating and high level energy (electricity) to cover a significant fraction of the electricity demand. The study result shows that, GCSS offer some potential advantages over a separate GCSS consisting of side-by-side solar PV panels and thermosyphon solar water heaters, enabling faster introduction solar energy buildings. For the case study the annual specific rate of fossil fuel saving in electrical power grid amount 269.4  kg.fuel/year per square meter of the solar PV/T collectors as a result of 199.6 kW.hr/year.m² electrical, and 904.5 kW.hr/m².year thermal, power generation. However, solar PV/T collector concept results in lower direct electric and thermal power output, but the advantages are a potential of high specific rate of fossil fuel saving and good overall performance of the solar system. Such concept requires careful analysis on a case-by-case basis of potential future commercial applications, which may greatly benefit from cogeneration of hot water and electrical power.  [1] Hussain Alrobaei, 2007 , The Effectiveness of Combined Heat and Power Solar Water Heating Systems/ environmental-expert.com/resultarticlept.asp.   

Solar electricity and water pumping is a great match. Normally the sun is shining the most hours per day when water is needed the most. This matching of performance with need is a major reason for the economic advantage of solar pumping. Pumping water with solar electricity is rapidly becoming the first choice in many locations where conventional utility-provided power is not readily available or feasible. Applications for solar water pumps are diverse and include stock and game watering from bore holes, rivers and dams. However, the main applications of photovoltaic pumping are rural irrigation and water supply for rural communities, and other isolated sites, in particular in developing countries. Compared to the cost of extending power lines to a remote site, solar is an obvious option and can complement cattle watering or irrigation, since the supply of sunshine coincides with the demand for

water. The hot sunny days, when solar power is in greatest supply, are the same days when the demand for water is highest. On rainy overcast days, the demand for water is reduced or eliminated (in the case of irrigation).

Currently, grid connected photovoltaic powered and wind powered reverse osmosis desalination plant and water pumping system are considered the most promising alternatives [1,2].

[1] Hussain Alrobaei, 2004 , The Effectiveness of Renewable Energy Systems for Desalination and Water pumping/ The 5^th JORDANIAN Mechanical & Industrial Engineering Conference JMIEC 04, Amman – Jordan, 24 : 26 April , 2004.

[2] Hussain Alrobaei, 2006 , Grid Connected Renewable Energy Fired Reverse  Osmosis Desalination Plants/ The Energy Central Network/ energycentral.com/centers/knowledge/whitepapers.

Solar Photo-Voltaic (PV) and other renewable energy technologies are gaining acceptance as a way of maintaining and improving living standards without harming the environment. In recent years the idea of introducing solar PV power into the electrical network has become quite popular. The size of the Grid-Connected (GC) plants varies from a few kW to MW. A grid connected PV system is able to supply power into the electrical distribution grid of a utility company. In this way there is diversity in potential as the power is generated from all the generators in parallel. The performance ratios of GC systems are in the range of 40 to 70 %.

GC systems, such as PV in Buildings, also have a significant potential, as has been proved in countries where a partnership has been established between government and industry (e.g. The Netherlands, Germany, Japan) to increase market sizes whilst at the same time bringing down costs. Existing players are increasing manufacturing capacity, and new companies are entering the market. The application of Building Integrated (BI) PV systems is particularly interesting because it demonstrates several advantages compared with conventional PV power plants. Moreover, on-site generation has the additional efficiency benefit of avoiding the transmission and distribution losses associated with centralized generation.

The long-term goal is to realize GC Solar System (GCSS) that produce electrical as well as thermal energy at sufficiently low cost. This means that the  investment costs has to be lowered as much as possible. This can only be achieved by careful design, proper realization, optimization, standardization and mass production. In addition to this, PV/T building elements should also be designed in such a way that they meet architectural requirements and technical standards and look attractive to consumers as well. From this standpoint the recent study [1] was undertaken to include proposed GCSS targets the two dominating energy demands in residential buildings: low level energy for water heating and high level energy (electricity) to cover a significant fraction of the electricity demand.  [1] Hussain Alrobaei, 2007 , The Effectiveness of Combined Heat and Power Solar Water Heating Systems/ environmental-expert.com/resultarticlept.asp.    

Contrary to photovoltaics, where solar radiation is directly transformed into electricity by solar cells, solar thermal power plants boast high degrees of efficiency and low electricity production costs even in great heat. If solar thermal plants also utilize co-generated heat, e.g. for air-conditioning, for generating industrial process steam or for desalination of sea water, ideally up to 25 % of the captured radiation can be transformed into electricity and an additional 35 % into utilizable energy. According to the result of recent study, this exceeds the energy utilization efficiency of conventional photovoltaic plants by four to six times and implementation of combined RO and Multi-Effect Distillation (MED) scheme for repowering and modification of RO plant will increase the desalted water production in about 17022.9 ton/year for each MW design thermal energy of parabolic solar collector arrays.. Moreover Solar Combined RO/MED scheme [1] has the potential of boosting water output through simple or full integration at the same time reducing the power to water ratio by 29 %. Thereby, the proposed scheme is a promising technology for climate compatible power with such enormous potential that combined RO/MED units would allow 24 hr economical dispatch of desalted water with high maneuver of boosting electrical power in electrical power grid.

 [1] Hussain Alrobaei, 2007 , REPOWERING AND MODIFICATION OF GRID CONNECTED REVERSE OSMOSIS DESALINATION PLANTS / environmental-expert.com/resultarticlept.asp. 

Biogas Technology has a very significant role to play in large-scale dairy farms & sewage disposal. It is estimated that cattle dung, when passed through a Biogas unit, yields 30-40% more net energy and about 35-45% more Nitrogen in manure as compared with that obtained by burning dung cakes and ordinarily prepared compost, respectively. Besides, from a biogas plant both the products are obtained. With only minor modifications, microturbines can be run on waste methane from digesters at dairy, and poultry farm operations as easily as at wastewater treatment plants. The driver for farm operators is to manage wastes - especially manure. In addition to providing a treatment route for manure, with fertilizer as an end product, digestion eliminates problems that arise from storing manure in a lagoon, and prevents groundwater pollution. Moreover, Heat captured from the engine-generator and microturbine system is used to maintain the digester temperature and supply heat to the dairy center. When hot water from the generation equipment is not available or insufficient (such as during startup), boilers running on LP gas are used as heat sources. However Compared with putting microturbines at landfills or wastewater treatment plants, the costs of projects at agricultural and livestock operations are higher, for two reasons. The waste collection system is more complicated, and farm operators are less likely to already have a collection system or a digester in place.