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Free cooling based phase change materials (FCPCM) are promising sustainable technologies which could be used to store the cold energy available during summer nights in a sufficient latent heat storage for later utilisation during the daytime. This current work aims to evaluate the feasibility of FCPCM technology in hot arid regions where the cooling demand is dominant during most of the year round. Energy-Plus simulation engine was used to predict the cooling load of a selected case study in order to size the capacity of the storage medium. The flat-plate PCM panel storage system has been developed and assessed using computational fluid dynamics (CFD) modeling utilising ANSYS FLUENT. The influence of operating conditions on the system performance was discussed through studying the solidification and melting process characterisation of the PCM. The results indicate that the proposed system is capable of reducing the cooling load substantially and the temperature of air supplied by the system is well maintained within the summer comfort zone between 298.65 and 303.15 K under the case study climate for up to 14.5 hours during the discharging period.

Compressed Air Energy Storage (CAES) is widely recognized as a viable solution for large-scale grid integrated renewable energy systems in terms of load levelling to solve/minimize the intermittency effect of renewable energy systems especially with increased penetration of renewables to the grid. This study assesses the economic value of adding compressed air energy storage (CAES) plant to a renewable energy system and how this impacts the overall financial appeal of the system at hand, taking Egyptian grid as a case in point. Numerical modelling using MATLAB was performed to analyse the benefits of adding a CAES system to planned wind farms in Egypt by 2020 for both load-levelling as well as optimizing economic benefit. The results show that the addition of a CAES system would increase the profitability for the new Tariff for wind systems set by the Egyptian government with a NPV of $306m compared to a NPV of $207m of a stand-alone wind system at the end of 25 years of operation. Also, the economic benefits increase if the government provides subsidies for new installations of renewable energy systems, or by lowering the interest rates.

Solar energy assisted heat pump systems (SAHP) have been used in this application. SAHP system with solar collectors and the heat pump are combined into one unit so as to convey the solar energy to the refrigerant. The solar collector is used as the evaporator, where the refrigerant is directly vaporized by solar energy input. Due to the complicated technical issues associated with a combined system that provides air for space heating and domestic hot water, most of the previous studies have concentrated on water heater heat pump mechanism. The current work is aimed at examining the use of a new multi-functional heat pump (DX-SAMHP), air for space heating mutually with solar for domestic hot water without employing an auxiliary heater. Comprehensive experimental and analytical studies in the first of its kind have been performed on the new system. The novel system with ternary panels and the thermal performance of the collector has been examined in this study. Results indicate that the DX-SAMHP using solar inner and outer panels for space and water heating is a promising substitute for the existing DX-SAHP water heater. Compared to the conventional solar-assisted SAHP heat pump systems, the coefficient performance of the new design doubles that of the conventional DX-SAHP systems.

Amman, the capital city of Jordan, usually experiences a hot dry summer with high solar radiations and a cold-wet winter. While the entire state of Jordan faces serious shortages in energy sources, significant growth in both industrial investment and constructions is noticed in the last few years particularly in Amman. This includes construction of both apartment and office buildings using a relatively new construction systems/elements. In Amman, for instance, Double-skin facades (DSF) have recently been introduced to a few buildings. However, there are no noticeable studies showing how it will work under the climate of Amman. Literature from similar climates indicates that while DSF is expected to perform well in winter, summer overheating is a major problem in hot regions due to large glazed surfaces facing excessive direct solar gains that coincide with high ambient temperatures. Thus, it is highly important to investigate the operational performance of this relatively new system in such a climate before it is widely applied due to its advantages as a promising passive technology. This study aims to investigate the thermal performance of DSF integrated into office buildings in Amman. Intended work was conducted using TAS tool and based on Amman’s weather file. Results showed that integration of DSF into multi-storeys office buildings would generally increase indoor operative temperatures for both conditions. While this would lead to significant overheating in summer times, indoor thermal comfort would almost be achieved in winter with a slight possibility of overheating during peak hours. However, the reasonable operation of the system (i.e. openings control) would help to overcome potential overheating in winter, whereas applying passive cooling technologies is highly recommended for summer operation.

Buildings have a major contribution to the global energy consumption. Heating, ventilating and air conditioning systems (HVAC) are responsible for most of the energy use in buildings. Thus, clean and sustainable alternatives such as free cooling of buildings have recently gained much attention as means to reduce the operation hours and capacity of the conventional cooling and heating systems. The free cooling could be provided by collecting the natural cold energy during night time in appropriate thermal storage form and this could be retrieved when needed. Phase change materials are exploited by a number of investigators as a storage medium in free cooling applications, as these substances possess high energy densities, and absorb and release heat at a narrow temperature range, hence, the comfort temperature can be maintained day and night. The objectives of this article are to provide a comprehensive review on recent development on free cooling technologies incorporating latent heat storage and to shit lights on the most significant parameters affecting the performance of these materials in free cooling strategy. The outcomes of this review would be helpful in providing clear insight information on potential improvements that can be applied to the storage materials. All the reviewed studies demonstrated that the night cooling strategy using PCMs has the capacity to maintain the indoor temperature well within the comfort zone whilst providing a considerable reduction in cooling loads in all considered climates.

Thermal comfort in building is a trendy that has been under investigation by many researchers. The mosque, for Muslim worshippers, is one of the most popular religious buildings. The demand of new mosques is continuously increasing due to the increasing number of Muslims population and growth in both economic and urban land escape. Recently, there have been a reasonable number of researches that have been investigating the thermal performance of mosque buildings. As a matter of fact, the location of the mosque and the climate play key roles on mosque building thermal performance. Additionally, mosque buildings are unique because of the intermittent operation pattern and the varying number of the users, which require rather controlled heating or cooling strategies. Sustainable energy techniques are keystone that ensures low energy consumption and provide better indoor environment for users of buildings. On the other hand due to environmental pressure to suppress global warming, more energy efficient and sustainable buildings design is one of the current issues in building industries. This research explores application of sustainable technologies for mosque buildings in hot climate zone. A number of mosque buildings in different regions, time frame and climates have been studied, and application of passive techniques on these cases have been evaluated. Performance of these techniques on roofs including building insulation, shading and green roofing have been analysed taking into account the climate and building specifications. The preliminary results obtained from this research clearly indicate that, there are design correlations and guidelines to be established for the architects and mosque buildings designers under any given climate for a sustainable mosque building design. Use of these guidelines also have potential of financial saving appropriately applied in mosque buildings in hot arid climate.

Recently, more than 80% of total energy of commercial greenhouse in the northern hemisphere is used just for heating. Mostly, the energy loss happens up to 40% caused by the poor U-value of the façades. Therefore, by lowering the U-value would decrease the energy consumption significantly. This simulation is conducted using EnergyPlus software to calculate the heat loss, heating demand and daylighting of a greenhouse with different envelope materials especially novelty rooftop. The orientation of buildings and its effect to electricity generated by semi-transparent PV double glazing are also discussed. In addition, the effect of the novel rooftop to daylighting inside the greenhouse is also investigated. The simulation shows that use materials with low U-value and novel rooftop could decrease the source energy consumption by 65% which is remarkable compared to commercial greenhouse. Besides, the best orientation for the PV module of the greenhouse in Nottingham, UK is facing west-south-east. While the indoor daylighting factor declined up to 65%. Therefore, using PVs with high efficiency would diminish the electricity losses and could be used for lighting energy alternative and others.

The number of mosque buildings is continuously increasing with the Muslim population, which is in fast growth around the world. In particular, the demand of new mosque buildings is high in the urban areas, due to increasing urban population growth in many parts of Muslims countries, as a result of economic growth and political instabilities in some parts of the Muslims world. Mosques are becoming more overcrowded and as a result a number of researches have been conducted to address the issue of thermal comfort of mosque users. Additionally, mosque building is unique because of its intermittent operation and various users, which require a unique heating or cooling strategies. On the other hand due to environmental pressure to suppress global warming, more energy efficient and sustainable buildings design is one of the current issues in building industries. This research aims to explore the sustainable techniques for mosque buildings in different climate zones. This research assesses a number of mosques buildings in different parts of the world with different climate; and investigates the strategies employed to cool or heat these buildings depending on the climate and season. The effectiveness of the building features in relation to each climate are carefully analysed, and possibility of potential replication of these features elsewhere are examined. This paper examined two techniques, green roof and louver shading in hot arid climate. The eventual objectives are establishing a guideline for architects and mosques building designer at any climate in order to achieve sustainable mosque building. The study concludes that there is a potential saving of up to 10% in cooling loads when green roof and louvers shading are applied on simulated mosque building in Riyadh, thus achieving the environmental feasibility in addition to economic and social benefits.

Increase in energy usage, particularly from fossil fuel sources is widely understood to be responsible for the environmental problems (Climate Change) experienced globally today. Response to mitigating this anthropogenic induced consequence created the need for innovative low carbon and renewable technologies in buildings. In the UK presently, every new building is expected to be low-carbon and energy-efficient. However, it is widely acknowledged that significant differences often exist between designed and in-use performances of the buildings. Clients and end-users of these technologies appear not to be getting long term value for their investments; much attention has not been given to how these innovative technologies can be operated and maintained long into the future. Recent researches also underpin the fact that the wide information gap existing between designers and building end-users is one of the factors responsible for the performance-gap. This paper therefore presents excerpts of a research aimed at exploring a best practice approach to operability and maintainability of low-carbon-buildings. The research methodology involved the use of interviews, surveys and case study. Findings suggest that a properly prepared O&M manual is a potential document that that could bridge this gap and that it is an indispensable tool for the effective and efficient operation and maintenance of low carbon buildings.

There are 130 countries produces greenhouse vegetables commercially with more than 1.1 million acres in 2016. Most of the greenhouses deal with high operating costs due to the great energy needs. The high heat loss because of the greenhouse envelope material is responsible for the high energy demand in greenhouses. Nevertheless, each area having a specific need which affects to the energy level and conventional greenhouse technologies tend to have poor U-values. It causes energy for heating is very dominant up to 85% of the total greenhouse energy demand in cold climates countries. While, for the hot climate countries the energy for cooling is more prevalent. Therefore, this paper presents the latest technological developments used in greenhouses in various countries used to control the microclimate in the greenhouse focusing on passive techniques. It is found that PCM recently used to provide heating and cooling for Mediterranean climate. Moreover, closed greenhouse concept based system for Northern climatic improves the reduction energy demands by 80% with a potential payback of 6 years. Additionally, for most countries double glazing envelopes to be the most frequently powerful to increase the greenhouse performance.

An experimental investigation on the operating characteristics of cold storage ejector cooling system with finned tube inside a cylindrical PCM tank was presented in this paper. The PCM cold storage tank was coupled with the evaporator to store the excess cooling capacity of ejector cooling system and provide cooling effect when the ejector did not operate. Medium temperature source (from solar collector or industrial waste) at temperature of 120 °C was the main driving force for ejector cooling system. The performance parameters, such as temperature inside the PCM tank, inlet and outlet temperature of heat transfer fluid, cold storage rate and cold storage capacity were measured at various mass flow rates, at the evaporator temperature of 3–5 °C. The same testing parameters were measured for discharging process at the heat source temperature of 25 °C. The experimental results demonstrated that the PCM cold storage integrated with ejector could help to maintain a more stable COP for ejector cooling system. The effectiveness-NTU method was applied for characterizing the tube-in tank PCM storage system. The correlation of effectiveness as the function of mass flow rate was derived from experimental data, and was used as a design parameter for the PCM cold storage system.

Energy consumption in domestic buildings is dominated by space heating 60 percent followed by hot water 14 percent in the UK. Space heating and water heating confers a disparate set of industrial challenges to the manufacture and this is a very demanding objective, which necessitates novelty. Space heating and water heating functions will become more significant as the trend towards low energy homes rises for a fully integrated system. The most common practical heat storage's are water and latent heat of fusion storage media. The new Thermochemical reaction materials regarded as most promising materials for the ability of store sufficient heat for practical domestic requirements. The volume capacities of materials play a key role for choosing storage system and this have a direct bearing on the performance of the heat storage system for domestic heating and heating water. Innovative thermal energy storage was conducted in a new concept for domestic applications at the Laboratory University of Nottingham, UK. An initial result has been investigated experimentally.

Transport refrigeration contributes to anthropogenic global warming directly because of leakage of refrigerant, usually using high global warming potential (GWP) refrigerants, and indirectly because of the greenhouse gases emitted in driving the vehicle and the refrigeration system. A hybrid jet-pump CO2 compression system is being designed for transport refrigeration so that the GWP of the system is reduced and its performance improved. The jet-pump utilises waste heat from the exhaust gases of the engine to subcool the refrigerant and so enhance performance, reduce energy required from the engine and minimise GWP of the system. The hybrid jet-pump CO2 compression system has been simulated and its performance determined for different operating conditions and optimised using entropy generation minimisation. At an evaporator temperature of -18°C, an ambient temperature of 35°C and a generator temperature of 120°C, the COP increases from about 1.0 to 2.27 as the degree of subcooling increases from 0K to 20K. Similarly, compressor work is reduced by 24% at 20K subcooling. The optimum degree of subcooling was approximately 10K for the operating conditions described above. An improved COP is achieved whilst the size of heat exchangers required to operate the jet-pump are minimised with respect to the overall weight of the system and thus its impact on indirect emissions.

Solar energy assisted heat pump systems (SAHP) have been used in this application. SAHP system with solar collectors and the heat pump are combined into one unit so as to convey the solar energy to the refrigerant. The solar collector is used as the evaporator, where the refrigerant is directly vaporized by solar energy input. Due to the complicated technical issues associated with a combined system that provides air for space heating and domestic hot water, most of the previous studies have concentrated on water heater heat pump mechanism. The current work is aimed at examining the use of a new multi-functional heat pump (DX-SAMHP), air for space heating mutually with solar for domestic hot water without employing an auxiliary heater. Comprehensive experimental and analytical studies in the first of its kind have been performed on the new system. The novel system with ternary panels and the thermal performance of the collector has been examined in this study. Results indicate that the DX-SAMHP using solar inner and outer panels for space and water heating is a promising substitute for the existing DX-SAHP water heater. Compared to the conventional solar-assisted SAHP heat pump systems, the coefficient performance of the new design doubles that of the conventional DX-SAHP systems.

Compressed Air Energy Storage (CAES) is widely recognized as a viable solution for large-scale grid integrated renewable energy systems in terms of load levelling to solve/minimize the intermittency effect of renewable energy systems especially with increased penetration of renewables to the grid. This study assesses the economic value of adding compressed air energy storage (CAES) plant to a renewable energy system and how this impacts the overall financial appeal of the system at hand, taking Egyptian grid as a case in point. Numerical modelling using MATLAB was performed to analyse the benefits of adding a CAES system to planned wind farms in Egypt by 2020 for both load-levelling as well as optimizing economic benefit. The results show that the addition of a CAES system would increase the profitability for the new Tariff for wind systems set by the Egyptian government with a NPV of $306m compared to a NPV of $207m of a stand-alone wind system at the end of 25 years of operation. Also, the economic benefits increase if the government provides subsidies for new installations of renewable energy systems, or by lowering the interest rates.

Buildings have a major contribution to the global energy consumption. Heating, ventilating and air conditioning systems (HVAC) are responsible for most of the energy use in buildings. Thus, clean and sustainable alternatives such as free cooling of buildings have recently gained much attention as means to reduce the operation hours and capacity of the conventional cooling and heating systems. The free cooling could be provided by collecting the natural cold energy during night time in appropriate thermal storage form and this could be retrieved when needed. Phase change materials are exploited by a number of investigators as a storage medium in free cooling applications, as these substances possess high energy densities, and absorb and release heat at a narrow temperature range, hence, the comfort temperature can be maintained day and night. The objectives of this article are to provide a comprehensive review on recent development on free cooling technologies incorporating latent heat storage and to shit lights on the most significant parameters affecting the performance of these materials in free cooling strategy. The outcomes of this review would be helpful in providing clear insight information on potential improvements that can be applied to the storage materials. All the reviewed studies demonstrated that the night cooling strategy using PCMs has the capacity to maintain the indoor temperature well within the comfort zone whilst providing a considerable reduction in cooling loads in all considered climates.

There are 130 countries produces greenhouse vegetables commercially with more than 1.1 million acres in 2016. Most of the greenhouses deal with high operating costs due to the great energy needs. The high heat loss because of the greenhouse envelope material is responsible for the high energy demand in greenhouses. Nevertheless, each area having a specific need which affects to the energy level and conventional greenhouse technologies tend to have poor U-values. It causes energy for heating is very dominant up to 85% of the total greenhouse energy demand in cold climates countries. While, for the hot climate countries the energy for cooling is more prevalent. Therefore, this paper presents the latest technological developments used in greenhouses in various countries used to control the microclimate in the greenhouse focusing on passive techniques. It is found that PCM recently used to provide heating and cooling for Mediterranean climate. Moreover, closed greenhouse concept based system for Northern climatic improves the reduction energy demands by 80% with a potential payback of 6 years. Additionally, for most countries double glazing envelopes to be the most frequently powerful to increase the greenhouse performance.

Recently, more than 80% of total energy of commercial greenhouse in the northern hemisphere is used just for heating. Mostly, the energy loss happens up to 40% caused by the poor U-value of the façades. Therefore, by lowering the U-value would decrease the energy consumption significantly. This simulation is conducted using EnergyPlus software to calculate the heat loss, heating demand and daylighting of a greenhouse with different envelope materials especially novelty rooftop. The orientation of buildings and its effect to electricity generated by semi-transparent PV double glazing are also discussed. In addition, the effect of the novel rooftop to daylighting inside the greenhouse is also investigated. The simulation shows that use materials with low U-value and novel rooftop could decrease the source energy consumption by 65% which is remarkable compared to commercial greenhouse. Besides, the best orientation for the PV module of the greenhouse in Nottingham, UK is facing west-south-east. While the indoor daylighting factor declined up to 65%. Therefore, using PVs with high efficiency would diminish the electricity losses and could be used for lighting energy alternative and others.

Free cooling based phase change materials (FCPCM) are promising sustainable technologies which could be used to store the cold energy available during summer nights in a sufficient latent heat storage for later utilisation during the daytime. This current work aims to evaluate the feasibility of FCPCM technology in hot arid regions where the cooling demand is dominant during most of the year round. Energy-Plus simulation engine was used to predict the cooling load of a selected case study in order to size the capacity of the storage medium. The flat-plate PCM panel storage system has been developed and assessed using computational fluid dynamics (CFD) modeling utilising ANSYS FLUENT. The influence of operating conditions on the system performance was discussed through studying the solidification and melting process characterisation of the PCM. The results indicate that the proposed system is capable of reducing the cooling load substantially and the temperature of air supplied by the system is well maintained within the summer comfort zone between 298.65 and 303.15 K under the case study climate for up to 14.5 hours during the discharging period.

The number of mosque buildings is continuously increasing with the Muslim population, which is in fast growth around the world. In particular, the demand of new mosque buildings is high in the urban areas, due to increasing urban population growth in many parts of Muslims countries, as a result of economic growth and political instabilities in some parts of the Muslims world. Mosques are becoming more overcrowded and as a result a number of researches have been conducted to address the issue of thermal comfort of mosque users. Additionally, mosque building is unique because of its intermittent operation and various users, which require a unique heating or cooling strategies. On the other hand due to environmental pressure to suppress global warming, more energy efficient and sustainable buildings design is one of the current issues in building industries. This research aims to explore the sustainable techniques for mosque buildings in different climate zones. This research assesses a number of mosques buildings in different parts of the world with different climate; and investigates the strategies employed to cool or heat these buildings depending on the climate and season. The effectiveness of the building features in relation to each climate are carefully analysed, and possibility of potential replication of these features elsewhere are examined. This paper examined two techniques, green roof and louver shading in hot arid climate. The eventual objectives are establishing a guideline for architects and mosques building designer at any climate in order to achieve sustainable mosque building. The study concludes that there is a potential saving of up to 10% in cooling loads when green roof and louvers shading are applied on simulated mosque building in Riyadh, thus achieving the environmental feasibility in addition to economic and social benefits.

Amman, the capital city of Jordan, usually experiences a hot dry summer with high solar radiations and a cold-wet winter. While the entire state of Jordan faces serious shortages in energy sources, significant growth in both industrial investment and constructions is noticed in the last few years particularly in Amman. This includes construction of both apartment and office buildings using a relatively new construction systems/elements. In Amman, for instance, Double-skin facades (DSF) have recently been introduced to a few buildings. However, there are no noticeable studies showing how it will work under the climate of Amman. Literature from similar climates indicates that while DSF is expected to perform well in winter, summer overheating is a major problem in hot regions due to large glazed surfaces facing excessive direct solar gains that coincide with high ambient temperatures. Thus, it is highly important to investigate the operational performance of this relatively new system in such a climate before it is widely applied due to its advantages as a promising passive technology. This study aims to investigate the thermal performance of DSF integrated into office buildings in Amman. Intended work was conducted using TAS tool and based on Amman’s weather file. Results showed that integration of DSF into multi-storeys office buildings would generally increase indoor operative temperatures for both conditions. While this would lead to significant overheating in summer times, indoor thermal comfort would almost be achieved in winter with a slight possibility of overheating during peak hours. However, the reasonable operation of the system (i.e. openings control) would help to overcome potential overheating in winter, whereas applying passive cooling technologies is highly recommended for summer operation.

Increase in energy usage, particularly from fossil fuel sources is widely understood to be responsible for the environmental problems (Climate Change) experienced globally today. Response to mitigating this anthropogenic induced consequence created the need for innovative low carbon and renewable technologies in buildings. In the UK presently, every new building is expected to be low-carbon and energy-efficient. However, it is widely acknowledged that significant differences often exist between designed and in-use performances of the buildings. Clients and end-users of these technologies appear not to be getting long term value for their investments; much attention has not been given to how these innovative technologies can be operated and maintained long into the future. Recent researches also underpin the fact that the wide information gap existing between designers and building end-users is one of the factors responsible for the performance-gap. This paper therefore presents excerpts of a research aimed at exploring a best practice approach to operability and maintainability of low-carbon-buildings. The research methodology involved the use of interviews, surveys and case study. Findings suggest that a properly prepared O&M manual is a potential document that that could bridge this gap and that it is an indispensable tool for the effective and efficient operation and maintenance of low carbon buildings.

Thermal comfort in building is a trendy that has been under investigation by many researchers. The mosque, for Muslim worshippers, is one of the most popular religious buildings. The demand of new mosques is continuously increasing due to the increasing number of Muslims population and growth in both economic and urban land escape. Recently, there have been a reasonable number of researches that have been investigating the thermal performance of mosque buildings. As a matter of fact, the location of the mosque and the climate play key roles on mosque building thermal performance. Additionally, mosque buildings are unique because of the intermittent operation pattern and the varying number of the users, which require rather controlled heating or cooling strategies. Sustainable energy techniques are keystone that ensures low energy consumption and provide better indoor environment for users of buildings. On the other hand due to environmental pressure to suppress global warming, more energy efficient and sustainable buildings design is one of the current issues in building industries. This research explores application of sustainable technologies for mosque buildings in hot climate zone. A number of mosque buildings in different regions, time frame and climates have been studied, and application of passive techniques on these cases have been evaluated. Performance of these techniques on roofs including building insulation, shading and green roofing have been analysed taking into account the climate and building specifications. The preliminary results obtained from this research clearly indicate that, there are design correlations and guidelines to be established for the architects and mosque buildings designers under any given climate for a sustainable mosque building design. Use of these guidelines also have potential of financial saving appropriately applied in mosque buildings in hot arid climate.

An experimental investigation on the operating characteristics of cold storage ejector cooling system with finned tube inside a cylindrical PCM tank was presented in this paper. The PCM cold storage tank was coupled with the evaporator to store the excess cooling capacity of ejector cooling system and provide cooling effect when the ejector did not operate. Medium temperature source (from solar collector or industrial waste) at temperature of 120 °C was the main driving force for ejector cooling system. The performance parameters, such as temperature inside the PCM tank, inlet and outlet temperature of heat transfer fluid, cold storage rate and cold storage capacity were measured at various mass flow rates, at the evaporator temperature of 3–5 °C. The same testing parameters were measured for discharging process at the heat source temperature of 25 °C. The experimental results demonstrated that the PCM cold storage integrated with ejector could help to maintain a more stable COP for ejector cooling system. The effectiveness-NTU method was applied for characterizing the tube-in tank PCM storage system. The correlation of effectiveness as the function of mass flow rate was derived from experimental data, and was used as a design parameter for the PCM cold storage system.

Energy consumption in domestic buildings is dominated by space heating 60 percent followed by hot water 14 percent in the UK. Space heating and water heating confers a disparate set of industrial challenges to the manufacture and this is a very demanding objective, which necessitates novelty. Space heating and water heating functions will become more significant as the trend towards low energy homes rises for a fully integrated system. The most common practical heat storage's are water and latent heat of fusion storage media. The new Thermochemical reaction materials regarded as most promising materials for the ability of store sufficient heat for practical domestic requirements. The volume capacities of materials play a key role for choosing storage system and this have a direct bearing on the performance of the heat storage system for domestic heating and heating water. Innovative thermal energy storage was conducted in a new concept for domestic applications at the Laboratory University of Nottingham, UK. An initial result has been investigated experimentally.

Compressed Air Energy Storage (CAES) is widely recognized as a viable solution for large-scale grid integrated renewable energy systems in terms of load levelling to solve/minimize the intermittency effect of renewable energy systems especially with increased penetration of renewables to the grid. This study assesses the economic value of adding compressed air energy storage (CAES) plant to a renewable energy system and how this impacts the overall financial appeal of the system at hand, taking Egyptian grid as a case in point. Numerical modelling using MATLAB was performed to analyse the benefits of adding a CAES system to planned wind farms in Egypt by 2020 for both load-levelling as well as optimizing economic benefit. The results show that the addition of a CAES system would increase the profitability for the new Tariff for wind systems set by the Egyptian government with a NPV of $306m compared to a NPV of $207m of a stand-alone wind system at the end of 25 years of operation. Also, the economic benefits increase if the government provides subsidies for new installations of renewable energy systems, or by lowering the interest rates.

Buildings have a major contribution to the global energy consumption. Heating, ventilating and air conditioning systems (HVAC) are responsible for most of the energy use in buildings. Thus, clean and sustainable alternatives such as free cooling of buildings have recently gained much attention as means to reduce the operation hours and capacity of the conventional cooling and heating systems. The free cooling could be provided by collecting the natural cold energy during night time in appropriate thermal storage form and this could be retrieved when needed. Phase change materials are exploited by a number of investigators as a storage medium in free cooling applications, as these substances possess high energy densities, and absorb and release heat at a narrow temperature range, hence, the comfort temperature can be maintained day and night. The objectives of this article are to provide a comprehensive review on recent development on free cooling technologies incorporating latent heat storage and to shit lights on the most significant parameters affecting the performance of these materials in free cooling strategy. The outcomes of this review would be helpful in providing clear insight information on potential improvements that can be applied to the storage materials. All the reviewed studies demonstrated that the night cooling strategy using PCMs has the capacity to maintain the indoor temperature well within the comfort zone whilst providing a considerable reduction in cooling loads in all considered climates.

Transport refrigeration contributes to anthropogenic global warming directly because of leakage of refrigerant, usually using high global warming potential (GWP) refrigerants, and indirectly because of the greenhouse gases emitted in driving the vehicle and the refrigeration system. A hybrid jet-pump CO2 compression system is being designed for transport refrigeration so that the GWP of the system is reduced and its performance improved. The jet-pump utilises waste heat from the exhaust gases of the engine to subcool the refrigerant and so enhance performance, reduce energy required from the engine and minimise GWP of the system. The hybrid jet-pump CO2 compression system has been simulated and its performance determined for different operating conditions and optimised using entropy generation minimisation. At an evaporator temperature of -18°C, an ambient temperature of 35°C and a generator temperature of 120°C, the COP increases from about 1.0 to 2.27 as the degree of subcooling increases from 0K to 20K. Similarly, compressor work is reduced by 24% at 20K subcooling. The optimum degree of subcooling was approximately 10K for the operating conditions described above. An improved COP is achieved whilst the size of heat exchangers required to operate the jet-pump are minimised with respect to the overall weight of the system and thus its impact on indirect emissions.

Transport refrigeration contributes to anthropogenic global warming directly because of leakage of refrigerant, usually using high global warming potential (GWP) refrigerants, and indirectly because of the greenhouse gases emitted in driving the vehicle and the refrigeration system. A hybrid jet-pump CO2 compression system is being designed for transport refrigeration so that the GWP of the system is reduced and its performance improved. The jet-pump utilises waste heat from the exhaust gases of the engine to subcool the refrigerant and so enhance performance, reduce energy required from the engine and minimise GWP of the system. The hybrid jet-pump CO2 compression system has been simulated and its performance determined for different operating conditions and optimised using entropy generation minimisation. At an evaporator temperature of -18°C, an ambient temperature of 35°C and a generator temperature of 120°C, the COP increases from about 1.0 to 2.27 as the degree of subcooling increases from 0K to 20K. Similarly, compressor work is reduced by 24% at 20K subcooling. The optimum degree of subcooling was approximately 10K for the operating conditions described above. An improved COP is achieved whilst the size of heat exchangers required to operate the jet-pump are minimised with respect to the overall weight of the system and thus its impact on indirect emissions.

Compressed Air Energy Storage (CAES) is widely recognized as a viable solution for large-scale grid integrated renewable energy systems in terms of load levelling to solve/minimize the intermittency effect of renewable energy systems especially with increased penetration of renewables to the grid. This study assesses the economic value of adding compressed air energy storage (CAES) plant to a renewable energy system and how this impacts the overall financial appeal of the system at hand, taking Egyptian grid as a case in point. Numerical modelling using MATLAB was performed to analyse the benefits of adding a CAES system to planned wind farms in Egypt by 2020 for both load-levelling as well as optimizing economic benefit. The results show that the addition of a CAES system would increase the profitability for the new Tariff for wind systems set by the Egyptian government with a NPV of $306m compared to a NPV of $207m of a stand-alone wind system at the end of 25 years of operation. Also, the economic benefits increase if the government provides subsidies for new installations of renewable energy systems, or by lowering the interest rates.

Solar energy assisted heat pump systems (SAHP) have been used in this application. SAHP system with solar collectors and the heat pump are combined into one unit so as to convey the solar energy to the refrigerant. The solar collector is used as the evaporator, where the refrigerant is directly vaporized by solar energy input. Due to the complicated technical issues associated with a combined system that provides air for space heating and domestic hot water, most of the previous studies have concentrated on water heater heat pump mechanism. The current work is aimed at examining the use of a new multi-functional heat pump (DX-SAMHP), air for space heating mutually with solar for domestic hot water without employing an auxiliary heater. Comprehensive experimental and analytical studies in the first of its kind have been performed on the new system. The novel system with ternary panels and the thermal performance of the collector has been examined in this study. Results indicate that the DX-SAMHP using solar inner and outer panels for space and water heating is a promising substitute for the existing DX-SAHP water heater. Compared to the conventional solar-assisted SAHP heat pump systems, the coefficient performance of the new design doubles that of the conventional DX-SAHP systems.

Free cooling based phase change materials (FCPCM) are promising sustainable technologies which could be used to store the cold energy available during summer nights in a sufficient latent heat storage for later utilisation during the daytime. This current work aims to evaluate the feasibility of FCPCM technology in hot arid regions where the cooling demand is dominant during most of the year round. Energy-Plus simulation engine was used to predict the cooling load of a selected case study in order to size the capacity of the storage medium. The flat-plate PCM panel storage system has been developed and assessed using computational fluid dynamics (CFD) modeling utilising ANSYS FLUENT. The influence of operating conditions on the system performance was discussed through studying the solidification and melting process characterisation of the PCM. The results indicate that the proposed system is capable of reducing the cooling load substantially and the temperature of air supplied by the system is well maintained within the summer comfort zone between 298.65 and 303.15 K under the case study climate for up to 14.5 hours during the discharging period.

Amman, the capital city of Jordan, usually experiences a hot dry summer with high solar radiations and a cold-wet winter. While the entire state of Jordan faces serious shortages in energy sources, significant growth in both industrial investment and constructions is noticed in the last few years particularly in Amman. This includes construction of both apartment and office buildings using a relatively new construction systems/elements. In Amman, for instance, Double-skin facades (DSF) have recently been introduced to a few buildings. However, there are no noticeable studies showing how it will work under the climate of Amman. Literature from similar climates indicates that while DSF is expected to perform well in winter, summer overheating is a major problem in hot regions due to large glazed surfaces facing excessive direct solar gains that coincide with high ambient temperatures. Thus, it is highly important to investigate the operational performance of this relatively new system in such a climate before it is widely applied due to its advantages as a promising passive technology. This study aims to investigate the thermal performance of DSF integrated into office buildings in Amman. Intended work was conducted using TAS tool and based on Amman’s weather file. Results showed that integration of DSF into multi-storeys office buildings would generally increase indoor operative temperatures for both conditions. While this would lead to significant overheating in summer times, indoor thermal comfort would almost be achieved in winter with a slight possibility of overheating during peak hours. However, the reasonable operation of the system (i.e. openings control) would help to overcome potential overheating in winter, whereas applying passive cooling technologies is highly recommended for summer operation.

Buildings have a major contribution to the global energy consumption. Heating, ventilating and air conditioning systems (HVAC) are responsible for most of the energy use in buildings. Thus, clean and sustainable alternatives such as free cooling of buildings have recently gained much attention as means to reduce the operation hours and capacity of the conventional cooling and heating systems. The free cooling could be provided by collecting the natural cold energy during night time in appropriate thermal storage form and this could be retrieved when needed. Phase change materials are exploited by a number of investigators as a storage medium in free cooling applications, as these substances possess high energy densities, and absorb and release heat at a narrow temperature range, hence, the comfort temperature can be maintained day and night. The objectives of this article are to provide a comprehensive review on recent development on free cooling technologies incorporating latent heat storage and to shit lights on the most significant parameters affecting the performance of these materials in free cooling strategy. The outcomes of this review would be helpful in providing clear insight information on potential improvements that can be applied to the storage materials. All the reviewed studies demonstrated that the night cooling strategy using PCMs has the capacity to maintain the indoor temperature well within the comfort zone whilst providing a considerable reduction in cooling loads in all considered climates.

Recently, more than 80% of total energy of commercial greenhouse in the northern hemisphere is used just for heating. Mostly, the energy loss happens up to 40% caused by the poor U-value of the façades. Therefore, by lowering the U-value would decrease the energy consumption significantly. This simulation is conducted using EnergyPlus software to calculate the heat loss, heating demand and daylighting of a greenhouse with different envelope materials especially novelty rooftop. The orientation of buildings and its effect to electricity generated by semi-transparent PV double glazing are also discussed. In addition, the effect of the novel rooftop to daylighting inside the greenhouse is also investigated. The simulation shows that use materials with low U-value and novel rooftop could decrease the source energy consumption by 65% which is remarkable compared to commercial greenhouse. Besides, the best orientation for the PV module of the greenhouse in Nottingham, UK is facing west-south-east. While the indoor daylighting factor declined up to 65%. Therefore, using PVs with high efficiency would diminish the electricity losses and could be used for lighting energy alternative and others.

There are 130 countries produces greenhouse vegetables commercially with more than 1.1 million acres in 2016. Most of the greenhouses deal with high operating costs due to the great energy needs. The high heat loss because of the greenhouse envelope material is responsible for the high energy demand in greenhouses. Nevertheless, each area having a specific need which affects to the energy level and conventional greenhouse technologies tend to have poor U-values. It causes energy for heating is very dominant up to 85% of the total greenhouse energy demand in cold climates countries. While, for the hot climate countries the energy for cooling is more prevalent. Therefore, this paper presents the latest technological developments used in greenhouses in various countries used to control the microclimate in the greenhouse focusing on passive techniques. It is found that PCM recently used to provide heating and cooling for Mediterranean climate. Moreover, closed greenhouse concept based system for Northern climatic improves the reduction energy demands by 80% with a potential payback of 6 years. Additionally, for most countries double glazing envelopes to be the most frequently powerful to increase the greenhouse performance.

An experimental investigation on the operating characteristics of cold storage ejector cooling system with finned tube inside a cylindrical PCM tank was presented in this paper. The PCM cold storage tank was coupled with the evaporator to store the excess cooling capacity of ejector cooling system and provide cooling effect when the ejector did not operate. Medium temperature source (from solar collector or industrial waste) at temperature of 120 °C was the main driving force for ejector cooling system. The performance parameters, such as temperature inside the PCM tank, inlet and outlet temperature of heat transfer fluid, cold storage rate and cold storage capacity were measured at various mass flow rates, at the evaporator temperature of 3–5 °C. The same testing parameters were measured for discharging process at the heat source temperature of 25 °C. The experimental results demonstrated that the PCM cold storage integrated with ejector could help to maintain a more stable COP for ejector cooling system. The effectiveness-NTU method was applied for characterizing the tube-in tank PCM storage system. The correlation of effectiveness as the function of mass flow rate was derived from experimental data, and was used as a design parameter for the PCM cold storage system.

Thermal comfort in building is a trendy that has been under investigation by many researchers. The mosque, for Muslim worshippers, is one of the most popular religious buildings. The demand of new mosques is continuously increasing due to the increasing number of Muslims population and growth in both economic and urban land escape. Recently, there have been a reasonable number of researches that have been investigating the thermal performance of mosque buildings. As a matter of fact, the location of the mosque and the climate play key roles on mosque building thermal performance. Additionally, mosque buildings are unique because of the intermittent operation pattern and the varying number of the users, which require rather controlled heating or cooling strategies. Sustainable energy techniques are keystone that ensures low energy consumption and provide better indoor environment for users of buildings. On the other hand due to environmental pressure to suppress global warming, more energy efficient and sustainable buildings design is one of the current issues in building industries. This research explores application of sustainable technologies for mosque buildings in hot climate zone. A number of mosque buildings in different regions, time frame and climates have been studied, and application of passive techniques on these cases have been evaluated. Performance of these techniques on roofs including building insulation, shading and green roofing have been analysed taking into account the climate and building specifications. The preliminary results obtained from this research clearly indicate that, there are design correlations and guidelines to be established for the architects and mosque buildings designers under any given climate for a sustainable mosque building design. Use of these guidelines also have potential of financial saving appropriately applied in mosque buildings in hot arid climate.