Qudama Al-Yasiri | Szent István University (original) (raw)

Papers by Qudama Al-Yasiri

Case Studies in Construction Materials, 2021

Abstract In this paper, the thermal performance of phase change material (PCM) incorporated concr... more Abstract In this paper, the thermal performance of phase change material (PCM) incorporated concrete bricks is studied experimentally. Four concrete bricks (three with macroencapsulated PCM and one without PCM represented the reference) are fabricated, and their thermal performance is tested under hot climate conditions. The study considered the effect of PCM encapsulation heat transfer area on brick's thermal performance at the same PCM quantity. PCM bricks included three different PCM capsule arrangements in which the first brick involved one bulky capsule (Brick-B, 4*4*10 cm3), the second brick had two capsules (Brick-C, 4*4*5 cm3), and the third brick involved five PCM capsules (Brick-D, 4*4*2 cm3). The peak temperature reduction (PTR), the conductive heat transfer reduction (HTRc), and the time delay (TD) were presented and calculated, taking into account the inner and outer brick surface temperatures of PCM bricks compared with the reference brick. Results showed that concrete bricks' thermal performance could be remarkably improved using PCM even under maximum outdoor temperatures. Moreover, the best thermal performance is reported for Brick-D, in which the maximum PTR, HTRc, and TD are reached 156.5%, ∼61%, and ∼133%, respectively, compared with the reference brick under maximum outdoor temperatures.

Case Studies in Construction Materials, 2021

Applied Energy, 2022

Phase change materials (PCMs) can beneficially work as a successful thermal energy storage medium... more Phase change materials (PCMs) can beneficially work as a successful thermal energy storage medium in different applications. PCMs have shown a remarkable enhancement in building energy-saving and thermal comfort in hot locations. In this paper, the thermal behaviour of a PCM-enhanced thermally-poor building envelope is studied experimentally. To this aim, two identical rooms, one loaded with PCM (PCM room) and the other without (reference room), are built and tested under a severe hot climate of Al Amarah city, Iraq. Previously examined parameters, such as the optimal position and thickness of the PCM layer in the roof and the best-thermally performed PCM capsules integrated concrete bricks, are considered to build the PCM room. Several energetic and thermal comfort indicators such as maximum temperature reduction (MTR), average temperature fluctuation reduction (ATFR), decrement factor (DF), time lag (TL), operative temperature difference (OTD), discomfort hours reduction (DHR) and maximum heat gain reduction (MHGR) are determined and discussed to show the potential of PCM. The experimental results revealed that the incorporated PCM could remarkably improve the thermal performance of building envelope exposed to high outdoor temperatures. Amongst envelope elements and compared with the reference room, the roof and east wall of the PCM room recorded the best thermal behaviour, where the MTR difference, ATFR, DF, and TL difference reached 3.75 °C, 6.5 °C, 25.6%, 70 min for the roof, and 2.75 °C, 2.4 °C, 12.8% and 40 min for the east wall, respectively. Moreover, the PCM room shows a thermal comfort enhancement by 11.2% and 34.8%, considering the DHR and MHGR, respectively, compared with the reference one. The study highlighted that suitable ventilation means are necessary to improve the building performance and reach acceptable thermal comfort when the PCM is incorporated passively.

Energy Reports, 2022

Cooling and airconditioning systems are the primary consumers of building energy in hot and mixed... more Cooling and airconditioning systems are the primary consumers of building energy in hot and mixed climate locations. The reliance on traditional systems, driven electrically, is the main reason behind the deterioration and ever-increasing demand for energy in buildings. This is also associated with a vast amount of CO 2 emissions and other environmental concerns. Solar energy has been introduced as a crucial alternative for many applications, including cooling and airconditioning , which has been proven to be a reliable and excellent energy source. This paper presents and discusses a general overview of solar cooling and airconditioning systems (SCACSs) used for building applications. The popular SCACSs driven by solar thermal energy are elaborated in detail, considering their operation and development aspects. A comparison among solar thermal SCACSs is performed, taking into account several technical, operational, economic and environmental indicators. Some research gaps, recommendations, and conclusions are derived from the reviewed literature to understand and further develop this essential research domain.

AIP Conference Proceedings , 2021

The roof plays a predominant role in residential buildings’ energy efficiency in hot countries as... more The roof plays a predominant role in residential buildings’ energy efficiency in hot countries as it receives a significant amount of solar radiation during the summer months. Incorporating phase change material is considered a sustainable solution to improve building energy performance. In this paper, the energy-saving earned from incorporating separate phase change material panel into a composite flat roof is investigated experimentally under hot climatic conditions of Al Amarah city, south of Iraq. Two identical small-scale rooms (with and without phase change material layer) have installed considering composite flat roof and insulated floor and walls. The roofs are composed of Isogam (as a roofing layer), concrete (as the main roof layer) and gypsum board (as a cladding layer). The maximum temperature reduction, average temperature fluctuation reduction, decrement factor and time lag have been calculated and discussed. Results indicated that PCM could efficiently reduce heat transfer through the roof and contribute to building energy- saving. The maximum interior surface temperature is reduced by up to 8.75 °C in the PCM roof. Moreover, an average maximum temperature reduction, average temperature fluctuation reduction, decrement factor and time lag of respectively 10.65%, 7.68 °C, 0.522 and ∼100 min, is obtained from the modified roof compared to the reference roof.

Journal of energy storage, Sep 1, 2023

Case Studies in Construction Materials, Jun 1, 2021

Journal of Cleaner Production, Sep 1, 2022

Incorporating phase change material (PCM) into buildings in hot climates is an excellent strategy... more Incorporating phase change material (PCM) into buildings in hot climates is an excellent strategy for better thermal comfort and energy-saving in future smart cities. Nevertheless, PCM elements suffer from adverse temperature behaviour at night due to the dissipation of stored diurnal heat. Night ventilation has been proposed as a promising solution and clean strategy for decreasing indoor building temperature at night and increasing PCM benefits in the following cycle. In this study, the effect of the natural night ventilation (NNV) period on the thermal performance of a room-integrated PCM is investigated experimentally under hot summer conditions in Iraq. Six NNV periods (with 1 h increment) are studied for six consecutive days in terms of average indoor and operative temperature reduction. Moreover, the work is extended to study the average heat gain difference in each day cycle to show the contribution of PCM to energy-saving. The results showed a slight enhancement in the average indoor air temperature of the PCM room compared with another identical no-PCM room regardless of the NNV period due to high outdoor ambient temperature at night. However, NNV for 4 h can reduce the average indoor air temperature by 28.6% compared with 1 h of NNV, whereas a slight extra reduction was achieved for 5 and 6 h. Besides, NNV slightly affected the operative temperature at night against no impact during the day, which was more influenced by the solar radiation and high diurnal ambient temperature. The results further revealed that a total average heat gain difference of 63.1-87.9 W was achieved, in which the roof contributed by more than 44% in each cycle.

Case Studies in Construction Materials, Jul 1, 2023

Journal of Energy Storage

Journal of Engineering and Technological Sciences, 2019

In recent years, the summer season in Iraq has become longer and hotter than before, leading to h... more In recent years, the summer season in Iraq has become longer and hotter than before, leading to high cooling loads inside buildings and increased demand for electrical energy. The use of sustainable energy and insulation techniques for building envelopes are reasonable solutions for overcoming harsh weather conditions and reaching acceptable thermal comfort levels. In this study, a survey on more than 60 residential buildings in Al-Amarah City, Iraq, was conducted on 21 July 2018 to examine the nature of the most common construction materials used in the building envelopes. Furthermore, the cooling loads of building envelope elements, e.g. roof, external walls and windows, was calculated using the cooling load temperature difference/solar cooling load/cooling load factor method of ASHRAE. The results were tabulated and compared for each combination of elements. The results showed that reflective glass is the optimal choice for exterior windows. The 'clay"“insulation"“f...

Applied Energy, 2022

Phase change materials (PCMs) can beneficially work as a successful thermal energy storage medium... more Phase change materials (PCMs) can beneficially work as a successful thermal energy storage medium in different applications. PCMs have shown a remarkable enhancement in building energy-saving and thermal comfort in hot locations. In this paper, the thermal behaviour of a PCM-enhanced thermally-poor building envelope is studied experimentally. To this aim, two identical rooms, one loaded with PCM (PCM room) and the other without (reference room), are built and tested under a severe hot climate of Al Amarah city, Iraq. Previously examined parameters, such as the optimal position and thickness of the PCM layer in the roof and the best-thermally performed PCM capsules integrated concrete bricks, are considered to build the PCM room. Several energetic and thermal comfort indicators such as maximum temperature reduction (MTR), average temperature fluctuation reduction (ATFR), decrement factor (DF), time lag (TL), operative temperature difference (OTD), discomfort hours reduction (DHR) and maximum heat gain reduction (MHGR) are determined and discussed to show the potential of PCM. The experimental results revealed that the incorporated PCM could remarkably improve the thermal performance of building envelope exposed to high outdoor temperatures. Amongst envelope elements and compared with the reference room, the roof and east wall of the PCM room recorded the best thermal behaviour, where the MTR difference, ATFR, DF, and TL difference reached 3.75 °C, 6.5 °C, 25.6%, 70 min for the roof, and 2.75 °C, 2.4 °C, 12.8% and 40 min for the east wall, respectively. Moreover, the PCM room shows a thermal comfort enhancement by 11.2% and 34.8%, considering the DHR and MHGR, respectively, compared with the reference one. The study highlighted that suitable ventilation means are necessary to improve the building performance and reach acceptable thermal comfort when the PCM is incorporated passively.

Energy Reports , 2022

Cooling and airconditioning systems are the primary consumers of building energy in hot and mixed... more Cooling and airconditioning systems are the primary consumers of building energy in hot and mixed climate locations. The reliance on traditional systems, driven electrically, is the main reason behind the deterioration and ever-increasing demand for energy in buildings. This is also associated with a vast amount of CO 2 emissions and other environmental concerns. Solar energy has been introduced as a crucial alternative for many applications, including cooling and airconditioning , which has been proven to be a reliable and excellent energy source. This paper presents and discusses a general overview of solar cooling and airconditioning systems (SCACSs) used for building applications. The popular SCACSs driven by solar thermal energy are elaborated in detail, considering their operation and development aspects. A comparison among solar thermal SCACSs is performed, taking into account several technical, operational, economic and environmental indicators. Some research gaps, recommendations, and conclusions are derived from the reviewed literature to understand and further develop this essential research domain.

Analecta Technica Szegedinensia, 2021

Cooling and air-conditioning systems are responsible for the highest energy consumption in buildi... more Cooling and air-conditioning systems are responsible for the highest energy consumption in buildings located in hot areas. This high share does not only increase the building energy demand cost but also increases the environmental impact, the topmost awareness of the modern era. The development of traditional systems and reliance on renewable technologies have increased drastically in the last century but still lacks economic concerns. Passive cooling strategies have been introduced as a successful option to mitigate the energy demand and improve energy conservation in buildings. This paper shed light on some passive strategies that could be applied to minimise building cooling loads to encourage the movement towards healthier and more energy-efficient buildings. For this purpose, seven popular passive technologies have been discussed shortly: multi-panned windows, shading devices, insulations, green roofing, phase change materials, reflective coatings, and natural ventilation using the windcatcher technique. The analysis of each strategy has shown that the building energy could be improved remarkably. Furthermore, adopting more passive strategies can significantly enhance the building thermal comfort even under severe weather conditions.

Energy Conversion and Management: X, 2021

Phase change materials (PCMs) are successful thermal energy storage mediums in many thermal syste... more Phase change materials (PCMs) are successful thermal energy storage mediums in many thermal systems, including buildings. Identifying the best PCM candidate is a critical incorporation parameter that influences building thermal performance. This paper discusses the selection of potential PCM candidates that could be applied for building heating applications in cold locations. A qualitative decision matrix (QDM) is applied for several commercial PCMs after an extensive analysis of relevant literature studies. The melting temperature, heat of fusion, thermal conductivity, compatibility, flammability and cost of each PCM are considered in the QDM to find the most suitable candidates with the best effective properties and features. PCM properties/features are assigned with scores and weights in the QDM based on their importance for the application. Three scenarios are investigated in this work, including and excluding the PCM cost with varying and equal weights. Results showed that RT28HC had the highest score in all scenarios, followed by SavE®HS29 in the first scenario (when the cost is included) and PureTemp 32 in the second scenario without considering the cost. The methodology and results presented in this work are believed to be as efficient as logical for future studies compared with the traditional methods that rely on investigating the PCM thermo-physical properties.

Renewable Energy and Environmental Sustainability, 2021

In recent years, phase change materials (PCMs) have increasingly received attention in different ... more In recent years, phase change materials (PCMs) have increasingly received attention in different thermal energy storage and management fields. In the building sector, paraffin as a phase change material (PPCM) has been introduced as an efficient PCM incorporated in a building envelope, which showed remarkable results. However, the poor thermal conductivity of PPCM is still the topmost drawback in experimental and numerical investigations. In this paper, a general assessment of paraffins, their common uses and applications, have been presented with a particular focus on their potential in building envelope applications. Moreover, the general and desired properties of PPCM are highlighted and evaluated. The primary practical limitation of PPCM of poor thermal conductivity and their effect on PPCM performance is presented and discussed. Correspondingly, the popular techniques applied to improve the poor thermal conductivity are presented and discussed in four categories: the dispersion of nanoparticles, expanded graphite, metallic foam, and extended surfaces technique (fins). All in all, the analysed research works indicated that PPCM based building envelope applications could remarkably improve the thermal performance of buildings in terms of thermal load reduction, energy-saving and thermal comfort. Furthermore, the adoption of enhancement techniques is essential to improve the thermal performance of PPCM in building applications for better utilisation. This review provides a clear vision for the newcomers and interested parties about the main application aspects of PPCM in the building sector for further investigations towards technology commercialisation.

AIP Conference Proceedings, 2021

The roof plays a predominant role in residential buildings' energy efficiency in hot countries as... more The roof plays a predominant role in residential buildings' energy efficiency in hot countries as it receives a significant amount of solar radiation during the summer months. Incorporating phase change material is considered a sustainable solution to improve building energy performance. In this paper, the energy-saving earned from incorporating separate phase change material panel into a composite flat roof is investigated experimentally under hot climatic conditions of Al Amarah city, south of Iraq. Two identical small-scale rooms (with and without phase change material layer) have been installed considering composite flat roof and insulated floor and walls. The roofs are composed of Isogam (as a roofing layer), concrete (as the main roof layer) and gypsum board (as a cladding layer). The maximum temperature reduction, average temperature fluctuation reduction, decrement factor and time lag have been calculated and discussed. Results indicated that PCM could efficiently reduce heat transfer through the roof and contribute to building energy saving. The maximum interior surface temperature is reduced by up to 8.75 °C in the PCM roof. Moreover, an average maximum temperature reduction, average temperature fluctuation reduction, decrement factor and time lag of respectively 10.65%, 7.68 °C, 0.522 and ~100 min, is obtained from the modified roof compared to the reference roof.

Case Studies in Construction Materials, 2021

In this paper, the thermal performance of phase change material (PCM) incorporated concrete brick... more In this paper, the thermal performance of phase change material (PCM) incorporated concrete bricks is studied experimentally. Four concrete bricks (three with macroencapsulated PCM and one without PCM represented the reference) are fabricated, and their thermal performance is tested under hot climate conditions. The study considered the effect of PCM encapsulation heat transfer area on brick's thermal performance at the same PCM quantity. PCM bricks included three different PCM capsule arrangements in which the first brick involved one bulky capsule (Brick-B, 4*4*10 cm 3), the second brick had two capsules (Brick-C, 4*4*5 cm 3), and the third brick involved five PCM capsules (Brick-D, 4*4*2 cm 3). The peak temperature reduction (PTR), the conductive heat transfer reduction (HTRc), and the time delay (TD) were presented and calculated, taking into account the inner and outer brick surface temperatures of PCM bricks compared with the reference brick. Results showed that concrete bricks' thermal performance could be remarkably improved using PCM even under maximum outdoor temperatures. Moreover, the best thermal performance is reported for Brick-D, in which the maximum PTR, HTRc, and TD are reached 156.5 %, ~61 %, and ~133 %, respectively, compared with the reference brick under maximum outdoor temperatures.

Case Studies in Construction Materials, 2021

Abstract In this paper, the thermal performance of phase change material (PCM) incorporated concr... more Abstract In this paper, the thermal performance of phase change material (PCM) incorporated concrete bricks is studied experimentally. Four concrete bricks (three with macroencapsulated PCM and one without PCM represented the reference) are fabricated, and their thermal performance is tested under hot climate conditions. The study considered the effect of PCM encapsulation heat transfer area on brick's thermal performance at the same PCM quantity. PCM bricks included three different PCM capsule arrangements in which the first brick involved one bulky capsule (Brick-B, 4*4*10 cm3), the second brick had two capsules (Brick-C, 4*4*5 cm3), and the third brick involved five PCM capsules (Brick-D, 4*4*2 cm3). The peak temperature reduction (PTR), the conductive heat transfer reduction (HTRc), and the time delay (TD) were presented and calculated, taking into account the inner and outer brick surface temperatures of PCM bricks compared with the reference brick. Results showed that concrete bricks' thermal performance could be remarkably improved using PCM even under maximum outdoor temperatures. Moreover, the best thermal performance is reported for Brick-D, in which the maximum PTR, HTRc, and TD are reached 156.5%, ∼61%, and ∼133%, respectively, compared with the reference brick under maximum outdoor temperatures.

Case Studies in Construction Materials, 2021

Applied Energy, 2022

Phase change materials (PCMs) can beneficially work as a successful thermal energy storage medium... more Phase change materials (PCMs) can beneficially work as a successful thermal energy storage medium in different applications. PCMs have shown a remarkable enhancement in building energy-saving and thermal comfort in hot locations. In this paper, the thermal behaviour of a PCM-enhanced thermally-poor building envelope is studied experimentally. To this aim, two identical rooms, one loaded with PCM (PCM room) and the other without (reference room), are built and tested under a severe hot climate of Al Amarah city, Iraq. Previously examined parameters, such as the optimal position and thickness of the PCM layer in the roof and the best-thermally performed PCM capsules integrated concrete bricks, are considered to build the PCM room. Several energetic and thermal comfort indicators such as maximum temperature reduction (MTR), average temperature fluctuation reduction (ATFR), decrement factor (DF), time lag (TL), operative temperature difference (OTD), discomfort hours reduction (DHR) and maximum heat gain reduction (MHGR) are determined and discussed to show the potential of PCM. The experimental results revealed that the incorporated PCM could remarkably improve the thermal performance of building envelope exposed to high outdoor temperatures. Amongst envelope elements and compared with the reference room, the roof and east wall of the PCM room recorded the best thermal behaviour, where the MTR difference, ATFR, DF, and TL difference reached 3.75 °C, 6.5 °C, 25.6%, 70 min for the roof, and 2.75 °C, 2.4 °C, 12.8% and 40 min for the east wall, respectively. Moreover, the PCM room shows a thermal comfort enhancement by 11.2% and 34.8%, considering the DHR and MHGR, respectively, compared with the reference one. The study highlighted that suitable ventilation means are necessary to improve the building performance and reach acceptable thermal comfort when the PCM is incorporated passively.

Energy Reports, 2022

Cooling and airconditioning systems are the primary consumers of building energy in hot and mixed... more Cooling and airconditioning systems are the primary consumers of building energy in hot and mixed climate locations. The reliance on traditional systems, driven electrically, is the main reason behind the deterioration and ever-increasing demand for energy in buildings. This is also associated with a vast amount of CO 2 emissions and other environmental concerns. Solar energy has been introduced as a crucial alternative for many applications, including cooling and airconditioning , which has been proven to be a reliable and excellent energy source. This paper presents and discusses a general overview of solar cooling and airconditioning systems (SCACSs) used for building applications. The popular SCACSs driven by solar thermal energy are elaborated in detail, considering their operation and development aspects. A comparison among solar thermal SCACSs is performed, taking into account several technical, operational, economic and environmental indicators. Some research gaps, recommendations, and conclusions are derived from the reviewed literature to understand and further develop this essential research domain.

AIP Conference Proceedings , 2021

The roof plays a predominant role in residential buildings’ energy efficiency in hot countries as... more The roof plays a predominant role in residential buildings’ energy efficiency in hot countries as it receives a significant amount of solar radiation during the summer months. Incorporating phase change material is considered a sustainable solution to improve building energy performance. In this paper, the energy-saving earned from incorporating separate phase change material panel into a composite flat roof is investigated experimentally under hot climatic conditions of Al Amarah city, south of Iraq. Two identical small-scale rooms (with and without phase change material layer) have installed considering composite flat roof and insulated floor and walls. The roofs are composed of Isogam (as a roofing layer), concrete (as the main roof layer) and gypsum board (as a cladding layer). The maximum temperature reduction, average temperature fluctuation reduction, decrement factor and time lag have been calculated and discussed. Results indicated that PCM could efficiently reduce heat transfer through the roof and contribute to building energy- saving. The maximum interior surface temperature is reduced by up to 8.75 °C in the PCM roof. Moreover, an average maximum temperature reduction, average temperature fluctuation reduction, decrement factor and time lag of respectively 10.65%, 7.68 °C, 0.522 and ∼100 min, is obtained from the modified roof compared to the reference roof.

Journal of energy storage, Sep 1, 2023

Case Studies in Construction Materials, Jun 1, 2021

Journal of Cleaner Production, Sep 1, 2022

Incorporating phase change material (PCM) into buildings in hot climates is an excellent strategy... more Incorporating phase change material (PCM) into buildings in hot climates is an excellent strategy for better thermal comfort and energy-saving in future smart cities. Nevertheless, PCM elements suffer from adverse temperature behaviour at night due to the dissipation of stored diurnal heat. Night ventilation has been proposed as a promising solution and clean strategy for decreasing indoor building temperature at night and increasing PCM benefits in the following cycle. In this study, the effect of the natural night ventilation (NNV) period on the thermal performance of a room-integrated PCM is investigated experimentally under hot summer conditions in Iraq. Six NNV periods (with 1 h increment) are studied for six consecutive days in terms of average indoor and operative temperature reduction. Moreover, the work is extended to study the average heat gain difference in each day cycle to show the contribution of PCM to energy-saving. The results showed a slight enhancement in the average indoor air temperature of the PCM room compared with another identical no-PCM room regardless of the NNV period due to high outdoor ambient temperature at night. However, NNV for 4 h can reduce the average indoor air temperature by 28.6% compared with 1 h of NNV, whereas a slight extra reduction was achieved for 5 and 6 h. Besides, NNV slightly affected the operative temperature at night against no impact during the day, which was more influenced by the solar radiation and high diurnal ambient temperature. The results further revealed that a total average heat gain difference of 63.1-87.9 W was achieved, in which the roof contributed by more than 44% in each cycle.

Case Studies in Construction Materials, Jul 1, 2023

Journal of Energy Storage

Journal of Engineering and Technological Sciences, 2019

In recent years, the summer season in Iraq has become longer and hotter than before, leading to h... more In recent years, the summer season in Iraq has become longer and hotter than before, leading to high cooling loads inside buildings and increased demand for electrical energy. The use of sustainable energy and insulation techniques for building envelopes are reasonable solutions for overcoming harsh weather conditions and reaching acceptable thermal comfort levels. In this study, a survey on more than 60 residential buildings in Al-Amarah City, Iraq, was conducted on 21 July 2018 to examine the nature of the most common construction materials used in the building envelopes. Furthermore, the cooling loads of building envelope elements, e.g. roof, external walls and windows, was calculated using the cooling load temperature difference/solar cooling load/cooling load factor method of ASHRAE. The results were tabulated and compared for each combination of elements. The results showed that reflective glass is the optimal choice for exterior windows. The 'clay"“insulation"“f...

Applied Energy, 2022

Phase change materials (PCMs) can beneficially work as a successful thermal energy storage medium... more Phase change materials (PCMs) can beneficially work as a successful thermal energy storage medium in different applications. PCMs have shown a remarkable enhancement in building energy-saving and thermal comfort in hot locations. In this paper, the thermal behaviour of a PCM-enhanced thermally-poor building envelope is studied experimentally. To this aim, two identical rooms, one loaded with PCM (PCM room) and the other without (reference room), are built and tested under a severe hot climate of Al Amarah city, Iraq. Previously examined parameters, such as the optimal position and thickness of the PCM layer in the roof and the best-thermally performed PCM capsules integrated concrete bricks, are considered to build the PCM room. Several energetic and thermal comfort indicators such as maximum temperature reduction (MTR), average temperature fluctuation reduction (ATFR), decrement factor (DF), time lag (TL), operative temperature difference (OTD), discomfort hours reduction (DHR) and maximum heat gain reduction (MHGR) are determined and discussed to show the potential of PCM. The experimental results revealed that the incorporated PCM could remarkably improve the thermal performance of building envelope exposed to high outdoor temperatures. Amongst envelope elements and compared with the reference room, the roof and east wall of the PCM room recorded the best thermal behaviour, where the MTR difference, ATFR, DF, and TL difference reached 3.75 °C, 6.5 °C, 25.6%, 70 min for the roof, and 2.75 °C, 2.4 °C, 12.8% and 40 min for the east wall, respectively. Moreover, the PCM room shows a thermal comfort enhancement by 11.2% and 34.8%, considering the DHR and MHGR, respectively, compared with the reference one. The study highlighted that suitable ventilation means are necessary to improve the building performance and reach acceptable thermal comfort when the PCM is incorporated passively.

Energy Reports , 2022

Cooling and airconditioning systems are the primary consumers of building energy in hot and mixed... more Cooling and airconditioning systems are the primary consumers of building energy in hot and mixed climate locations. The reliance on traditional systems, driven electrically, is the main reason behind the deterioration and ever-increasing demand for energy in buildings. This is also associated with a vast amount of CO 2 emissions and other environmental concerns. Solar energy has been introduced as a crucial alternative for many applications, including cooling and airconditioning , which has been proven to be a reliable and excellent energy source. This paper presents and discusses a general overview of solar cooling and airconditioning systems (SCACSs) used for building applications. The popular SCACSs driven by solar thermal energy are elaborated in detail, considering their operation and development aspects. A comparison among solar thermal SCACSs is performed, taking into account several technical, operational, economic and environmental indicators. Some research gaps, recommendations, and conclusions are derived from the reviewed literature to understand and further develop this essential research domain.

Analecta Technica Szegedinensia, 2021

Cooling and air-conditioning systems are responsible for the highest energy consumption in buildi... more Cooling and air-conditioning systems are responsible for the highest energy consumption in buildings located in hot areas. This high share does not only increase the building energy demand cost but also increases the environmental impact, the topmost awareness of the modern era. The development of traditional systems and reliance on renewable technologies have increased drastically in the last century but still lacks economic concerns. Passive cooling strategies have been introduced as a successful option to mitigate the energy demand and improve energy conservation in buildings. This paper shed light on some passive strategies that could be applied to minimise building cooling loads to encourage the movement towards healthier and more energy-efficient buildings. For this purpose, seven popular passive technologies have been discussed shortly: multi-panned windows, shading devices, insulations, green roofing, phase change materials, reflective coatings, and natural ventilation using the windcatcher technique. The analysis of each strategy has shown that the building energy could be improved remarkably. Furthermore, adopting more passive strategies can significantly enhance the building thermal comfort even under severe weather conditions.

Energy Conversion and Management: X, 2021

Phase change materials (PCMs) are successful thermal energy storage mediums in many thermal syste... more Phase change materials (PCMs) are successful thermal energy storage mediums in many thermal systems, including buildings. Identifying the best PCM candidate is a critical incorporation parameter that influences building thermal performance. This paper discusses the selection of potential PCM candidates that could be applied for building heating applications in cold locations. A qualitative decision matrix (QDM) is applied for several commercial PCMs after an extensive analysis of relevant literature studies. The melting temperature, heat of fusion, thermal conductivity, compatibility, flammability and cost of each PCM are considered in the QDM to find the most suitable candidates with the best effective properties and features. PCM properties/features are assigned with scores and weights in the QDM based on their importance for the application. Three scenarios are investigated in this work, including and excluding the PCM cost with varying and equal weights. Results showed that RT28HC had the highest score in all scenarios, followed by SavE®HS29 in the first scenario (when the cost is included) and PureTemp 32 in the second scenario without considering the cost. The methodology and results presented in this work are believed to be as efficient as logical for future studies compared with the traditional methods that rely on investigating the PCM thermo-physical properties.

Renewable Energy and Environmental Sustainability, 2021

In recent years, phase change materials (PCMs) have increasingly received attention in different ... more In recent years, phase change materials (PCMs) have increasingly received attention in different thermal energy storage and management fields. In the building sector, paraffin as a phase change material (PPCM) has been introduced as an efficient PCM incorporated in a building envelope, which showed remarkable results. However, the poor thermal conductivity of PPCM is still the topmost drawback in experimental and numerical investigations. In this paper, a general assessment of paraffins, their common uses and applications, have been presented with a particular focus on their potential in building envelope applications. Moreover, the general and desired properties of PPCM are highlighted and evaluated. The primary practical limitation of PPCM of poor thermal conductivity and their effect on PPCM performance is presented and discussed. Correspondingly, the popular techniques applied to improve the poor thermal conductivity are presented and discussed in four categories: the dispersion of nanoparticles, expanded graphite, metallic foam, and extended surfaces technique (fins). All in all, the analysed research works indicated that PPCM based building envelope applications could remarkably improve the thermal performance of buildings in terms of thermal load reduction, energy-saving and thermal comfort. Furthermore, the adoption of enhancement techniques is essential to improve the thermal performance of PPCM in building applications for better utilisation. This review provides a clear vision for the newcomers and interested parties about the main application aspects of PPCM in the building sector for further investigations towards technology commercialisation.

AIP Conference Proceedings, 2021

The roof plays a predominant role in residential buildings' energy efficiency in hot countries as... more The roof plays a predominant role in residential buildings' energy efficiency in hot countries as it receives a significant amount of solar radiation during the summer months. Incorporating phase change material is considered a sustainable solution to improve building energy performance. In this paper, the energy-saving earned from incorporating separate phase change material panel into a composite flat roof is investigated experimentally under hot climatic conditions of Al Amarah city, south of Iraq. Two identical small-scale rooms (with and without phase change material layer) have been installed considering composite flat roof and insulated floor and walls. The roofs are composed of Isogam (as a roofing layer), concrete (as the main roof layer) and gypsum board (as a cladding layer). The maximum temperature reduction, average temperature fluctuation reduction, decrement factor and time lag have been calculated and discussed. Results indicated that PCM could efficiently reduce heat transfer through the roof and contribute to building energy saving. The maximum interior surface temperature is reduced by up to 8.75 °C in the PCM roof. Moreover, an average maximum temperature reduction, average temperature fluctuation reduction, decrement factor and time lag of respectively 10.65%, 7.68 °C, 0.522 and ~100 min, is obtained from the modified roof compared to the reference roof.

Case Studies in Construction Materials, 2021

In this paper, the thermal performance of phase change material (PCM) incorporated concrete brick... more In this paper, the thermal performance of phase change material (PCM) incorporated concrete bricks is studied experimentally. Four concrete bricks (three with macroencapsulated PCM and one without PCM represented the reference) are fabricated, and their thermal performance is tested under hot climate conditions. The study considered the effect of PCM encapsulation heat transfer area on brick's thermal performance at the same PCM quantity. PCM bricks included three different PCM capsule arrangements in which the first brick involved one bulky capsule (Brick-B, 4*4*10 cm 3), the second brick had two capsules (Brick-C, 4*4*5 cm 3), and the third brick involved five PCM capsules (Brick-D, 4*4*2 cm 3). The peak temperature reduction (PTR), the conductive heat transfer reduction (HTRc), and the time delay (TD) were presented and calculated, taking into account the inner and outer brick surface temperatures of PCM bricks compared with the reference brick. Results showed that concrete bricks' thermal performance could be remarkably improved using PCM even under maximum outdoor temperatures. Moreover, the best thermal performance is reported for Brick-D, in which the maximum PTR, HTRc, and TD are reached 156.5 %, ~61 %, and ~133 %, respectively, compared with the reference brick under maximum outdoor temperatures.