M.A. Alghoul, M.Y. Sulaiman, B.Z. Azmi, K. Sopian and M.Abd. Wahab
During the last 20 years, interest in the closed adsorption heat pump and refrigeration systems has increased steadily. In this paper, consideration is given to aspects of…
Abstract
Purpose
During the last 20 years, interest in the closed adsorption heat pump and refrigeration systems has increased steadily. In this paper, consideration is given to aspects of adsorption refrigeration in terms of existing materials used in adsorption refrigeration, heat transfer characteristics of materials, and cost of materials and manufacturing.
Design/methodology/approach
The paper is a general review of adsorption refrigeration technology.
Findings
In recent years several papers have been published in this area and many aspects of the system have been addressed. Much effort has been devoted to enhance materials properties.
Originality/value
The paper provides information of value to those involved with heat pump and refrigeration systems technology.
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M.A. Alghoul, M.Y. Sulaiman, B.Z. Azmi and M.Abd. Wahab
To cover the main contributions and developments in solar thermal collectors through focusing on materials, heat transfer characteristics and manufacturing challenges.
Abstract
Purpose
To cover the main contributions and developments in solar thermal collectors through focusing on materials, heat transfer characteristics and manufacturing challenges.
Design/methodology/approach
A range of published papers and internet research including research work on various solar thermal collectors (flat plate, evacuated tubes, and heat pipe tube) were used. Evaluation of solar collectors performance is critiqued to aid solar technologies make the transition into a specific dominant solar collector. The sources are sorted into sections: finding an academic job, general advice, teaching, research and publishing, tenure and organizations.
Findings
Provides information about types of solar thermal collectors, indicating what can be added by using evacuated tube collectors instead of flat plate collectors and what can be added by using heat pipe collectors instead of evacuated tubes.
Research limitations/implications
Focusing only on three types of solar thermal collectors (flat plate, evacuated tubes, and heat pipe tube).
Practical implications
Useful source of information for consultancy and impartial advice for graduate students planning to do research in solar thermal technologies.
Originality/value
This paper fulfils identified information about materials and heat transfer properties of materials and manufacturing challenges of these three solar thermal collectors.
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Anges Akim Aminou Moussavou, Ayokunle Oluwaseun Ayeleso, Marco Adonis and Atanda Raji
This paper aims to develop a selective energy optimisation of the photovoltaic–thermal (PV/T) system performance. The PV cell inside the PV/T system could be periodically…
Abstract
Purpose
This paper aims to develop a selective energy optimisation of the photovoltaic–thermal (PV/T) system performance. The PV cell inside the PV/T system could be periodically manipulated to produce domestic hot water without applying an external power supply.
Design/methodology/approach
A numerical simulation model of the proposed PV/T model was developed in MATLAB/Simulink to analyse the selective energy optimisation of the model. The extrinsic cell resistance (Rse) is adjusted to control the ratio of thermal to the electrical energy, generated from the PV cell inside the PV/T system. Therefore, the internal heat of the PV cell inside the PV/T system is periodically used as a thermal element to produce electrical power and hot water.
Findings
The optimisation of PV/T energy shows that the electrical power efficiency can increase by 11.6% when Rse was 0 Ω, and the 200 L water tank temperature increased by 22ºC when Rse was 50 Ω.
Originality/value
This study showed that the use of the PV cell could be extended to domestic hot water and space heating, and not only for electricity.
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João Paulo Nascimento Silva, Cledison Carlos de Oliveira, Gabriel Pedrosa and André Grutzmann
This paper aims to analyse the technological, economic and environmental impacts of disruptive innovations in the transportation mobility market.
Abstract
Purpose
This paper aims to analyse the technological, economic and environmental impacts of disruptive innovations in the transportation mobility market.
Design/methodology/approach
The paper gathered data from World Bank and 13 open sources in an exploratory, descriptive and applied investigation on potentially disruptive transport innovations outcomes in G7 and BRICS (Brazil, Russian Federation, India, China and South Africa) economies, businesses and societies.
Findings
The results suggest positive implications for technological leapfrogging of electric vehicles (EV), autonomous vehicles (AVs) and electric vertical take-off and landing (eVTOLs), such as gains in energy consumption, infrastructure improvement, greenhouse gas emissions reduction, economic growth and the opportunity for new disruptive technologies to improve or even revolutionize the transportation ecosystem.
Research limitations/implications
This study has clear limitations as it compares G7 and BRICS hypothetical scenarios where internal combustion vehicles were replaced by new technologies, ceteris paribus. Even so, as theoretical implications, the study presents market scenarios for EVs, AVs and eVTOLs technologies, bringing benefits to the disruptive innovation theory by expanding the understanding of the subject and also opening avenues of investigation by exploring new technological, economic and environmental possibilities.
Practical implications
This study emphasises potentially disruptive technologies’ technological, economic and sustainable benefits to countries through technological leapfrogging. The organizations can delve into results to investigate forthcoming markets and seek advantageous positions. Economic and social gains from leapfrogging could motivate government bodies to finance research focusing on EVs, AVs and eVTOLs diffusion.
Originality/value
The paper’s originality resides in aggregating multiple data sources to compare technological leapfrogging in G7 and BRICS transportation. The different views allowed for exploring the potential outcomes of EVs, AVs and eVTOLs on economic, sustainability and market dimensions in developed and developing countries.
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B. Norerama D. Pagukuman and M. Kamel Wan Ibrahim
The purpose of this paper is to present and discuss the external factors of the solar dryer design that influenced the thermal efficiency of the solar dryer that contribute to the…
Abstract
Purpose
The purpose of this paper is to present and discuss the external factors of the solar dryer design that influenced the thermal efficiency of the solar dryer that contribute to the better quality of dried food products.
Design/methodology/approach
From the reviewed works of literature, the external factors including the drying temperature, airflow rate and relative humidity have significant effects to increase the rate of moisture diffusivity of the freshly harvested products during the drying process. The proper controls of airflow rate (Q), velocity (V), relative humidity (RH%) and drying temperature (°C) can influence the dried product quality. The dehydration ratio is the procedure to measure the quality of the dried food product.
Findings
The indirect solar dryer including the mixed-mode, hybrid and integrated was found shorter in drying time and energy-intensive compared to sun drying and direct drying. The recommended drying temperature is from 35.5°C to 70°C with 1–2 m/s velocity and 20%–60% relative humidity. The optimum thermal efficiency can be reached by additional devices, including solar collectors and solar accumulators. It gives a simultaneous effect and elongated the drying temperature 8%–10% higher than ambient temperature with 34%–40% energy saving. The recommended airflow rate for drying is 0.1204 to 0.0894 kg/s. Meanwhile, an airflow rate at 0.035–0.04 kg/m2 is recommended for an optimum drying kinetic performance.
Research limitations/implications
This paper discusses the influence of the external factors of the solar dryer design on the thermal performance of the solar dryer and final dried food products quality. Therefore, the findings cannot serve as a statistical generalization but should instead be viewed as the quantitative validation subjected to fundamentals of the solar dryer design process and qualitative observation of the dried food product quality.
Practical implications
A well-designed of solar dryer with low operating and initial fabrication cost, which is simple to operate is useful for the farmers to preserve surplus harvested crops to an acceptable and marketable foods product. The optimization of the external and internal factors can contribute to solar dryer thermal performance that later provides an organoleptic drying condition that results in good quality of dried product and better drying process. The recommended drying temperature for a drying method is between 35°C up to 70°C. Drying at 65.56°C was effective to kill microorganisms. Meanwhile, drying at 50°C consider as average drying temperature. The recommended airflow rate for drying is 0.1204 to 0.0894 kg/s. Meanwhile, air flowrate at 0.035–0.04 kg/m2 is recommended for optimum drying kinetic performance. The recommended value of aspect ratio and mass flow rate is 200 to 300 for an optimum evaporation rate. The good quality of dried products and good performance of solar dryers can be developed by proper control of airflow rate (Q), velocity (V), relative humidity (RH%) and drying temperature (°C).
Social implications
The proper control of the drying temperature, relative humidity and airflow rate during the drying process will influence the final dried food products in terms of shape, color, aroma, texture, rupture and nutritious value. It is crucial to control the drying parameters because over-drying caused an increment of energy cost and reduces the dry matter. The quick-drying will disturb the chemical process during fermentation to be completed.
Originality/value
This study identifies the potential of the solar drying method for dehydrating agricultural produces for later use with the organoleptic drying process. The organoleptic drying process can reduce mold growth by promising an effective diffusion of moisture from freshly harvested products. The research paper gives useful understandings that well-designed solar drying technology gives a significant effect on dried product quality.
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Ataollah Khanlari, Faraz Afshari, Adnan Sözen, Azim Doğuş Tuncer and Barış Kusun
During the past several years, research and studies in the field of solar energy have been continuously increased. One of the substantial applications of solar energy is related…
Abstract
Purpose
During the past several years, research and studies in the field of solar energy have been continuously increased. One of the substantial applications of solar energy is related to industrial utilization for the drying process by efficient heat transfer methods. This study aims to upgrade the overall performance of an indirect solar dryer using a solar absorber extension tube (SET) equipped with ball-type turbulators.
Design/methodology/approach
In this work, three various SETs including hollow (SET Type 1), 6-balls (SET Type 2) and 10-balls (SET Type 3), have been simulated using Fluent software to evaluate heat transfer characteristics and flow structure along the air passage. Then, the modified solar drying system has been manufactured and tested at different configurations.
Findings
The findings indicated that adding a SET improved the performance notably. According to the results, using turbulators in the tube has a positive effect on heat transfer. The highest overall thermal efficiency was found in the range of 51.47%–64.71% for the system with SET Type 3. The maximum efficiency increment of the system was found as 19% with the use of SET. Also, the average specific moisture extraction rate, which is a significant factor to survey the effectiveness of the dehumidification system was found between 0.20 and 0.38 kg kWh−1.
Originality/value
In the present study, a novel SET has been developed to upgrade the performance of the solar dehumidifier. This new approach makes it possible to improve both thermal and drying performances.
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Norhayati Mahyuddin, Mozhgan Samzadeh, Suzaini M. Zaid and Norafida Ab Ghafar
This paper aims to raise awareness on how a simple action by the occupant can significantly influence building energy efficiency, cost and CO2 emissions to the environment…
Abstract
Purpose
This paper aims to raise awareness on how a simple action by the occupant can significantly influence building energy efficiency, cost and CO2 emissions to the environment. Classrooms in schools are the primary energy consumers (45.4%) due to the use of artificial lighting, despite Malaysia's tropical climate being ideal for daylight exploitation. This paper focuses on assessing the workplane daylight distribution quality and quantity in baseline and existing conditions of a typical pre-school classroom in Kuala Lumpur as a model-based exploration strategy towards nearly Zero Energy Buildings.
Design/methodology/approach
The adopted method is based on the calculation of average daylight factor (DF), daylight illuminance level (IL) and uniformity ratio (UR) parameters affected by the internal fixed drapes through computational and in situ measurements according to the requirements of the law and respective standards comprising the MS1525:2019, GBI and BREEAM.
Findings
The results show how user behaviour can turn a well-daylit area (Net Lettable Area>90%) into a poor-daylit area (NLA<5%) by sacrificing natural daylight. All the parameters' values were significantly decreased from 10% (UR) up to 88% (ADF). Full dependency on artificial lighting has imposed a total of RM18858.90 and CO2 emissions of 25,362 kg for all pre-schools' classrooms in the country per day.
Social implications
The paper develops the occupants' awareness on their contribution to climate change and global warming through the information and transparency provided.
Originality/value
The evidence indicates that a simple action by the occupant can significantly influence visual comfort, EE, cost and CO2 emissions to the environment.
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Keywords
Francesco De Luca, Raimo Simson, Hendrik Voll and Jarek Kurnitski
Electric lighting accounts for a large share of energy consumption in commercial buildings. Utilization of daylight can significantly help to reduce the need for artificial…
Abstract
Purpose
Electric lighting accounts for a large share of energy consumption in commercial buildings. Utilization of daylight can significantly help to reduce the need for artificial lighting, increase workers productivity, customers’ satisfaction and consequently improve sales. However, excessive use of glazing and absence of lighting controls can contribute greatly to higher energy need for heating and cooling and cause undesired glare effects. Thus, optimizing the size, position and materials of external glazing, with the addition of deflectors and dynamic artificial lighting, can become key aspects in the design of sustainable low energy buildings. The purpose of this paper is to analyze daylight potential and energy performance of a hall-type commercial building, situated in the cold climate of Finland, by utilizing different combinations of skylights, windows and lighting controls.
Design/methodology/approach
The authors have used computer simulations to estimate daylight and energy performance of a single floor commercial building in relation to various combinations of skylights and windows with variable glazing materials, light deflectors and zonal lighting controls.
Findings
The results show that electric light energy saving potential ranges from a negligible 1.9 percent to a significant 58.6 percent in the case of glass skylights and wall windows using multi-zone lighting control. Total delivered energy ranges between increase of 1.5 and 21.2 percent in the cases with single zone lighting control and between decrease of 4.5 percent and increase of 4.5 percent in the cases with multi-zone control. The highest decrease in primary energy consumption was 2.2 percent for single zone and 17.6 percent for multi-zone lighting control. The research underlines the significant potential of electric light energy savings using daylighting strategies that, including the control of direct solar access for glare and internal gains, can be more than 50 percent.
Originality/value
This research combines accurate daylight and energy assessment for commercial hall buildings based in cold climate region with multiple design variations. The novelty of this work is the consideration of interior elements, shelves and deflectors, in the calculations. This is made possible through the combined use of validated simulation platforms for detailed annual daylighting and electric lighting calculation (Radiance and Daysim) and energy analysis (IDA-ICE, Equa Simulation AB). This method allows to obtain a reliable assessment of the potential of using natural light sources in buildings.
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Christian Koranteng, Barbara Simons, Kwabena Abrokwa Gyimah and Jimmy Nkrumah
Accra, the capital city of Ghana, is seeing high-rise buildings springing up with extensive glazing. Given the challenges of the country concerning energy provision, guaranteeing…
Abstract
Purpose
Accra, the capital city of Ghana, is seeing high-rise buildings springing up with extensive glazing. Given the challenges of the country concerning energy provision, guaranteeing comfort in buildings and sustainability aspects, this trend is questionable and worrying in this pandemic era. Therefore, the purpose of this paper is to evaluate how glazing types and their properties could reduce cooling loads and provide comfort by following the recommendations set by the Ghana Green Building Council (GHGBC) after the Green Star of South Africa, as well as other references found in literature.
Design/methodology/approach
Indoor thermal conditions were monitored to evaluate prevailing indoor conditions. Using a simulation application, various options were probed based on the Green recommendations and others found in literature to improve thermal comfort within the structure. Moreover, a questionnaire survey with observation was undertaken with 250 architects to understand the basis of decisions taken when specifying glazing for buildings.
Findings
The results indicate that cooling loads increased by 2% when the GHGBC after the Green Star of South Africa recommendations were applied. However, the use of the recommendations of previous research conducted in Ghana could reduce cooling loads by 38% to save energy. Suggested strategies of air velocity up to 1.0 m/s as well as thermal mass, comfort ventilation, conventional dehumidification and air-conditioning were found to be means to improve indoor comfort. Furthermore, the architects revealed that around 40% of multi-storey buildings are 70%–100% glazed. Of all the buildings, 62.4% was found to be glazed with single pane windows, making them use so much energy in cooling. Additionally, the survey underlined the client’s preference, cost and functionality as the three main bases for the choice of glazing in multi-storey office buildings.
Originality/value
A significant contribution of this study to the body of knowledge is the provision of empirical evidence to support the fact that due to climate difference, each country needs to undertake more experimental research works to be able to come out with standards that work. Thus, the GHGBC after the Green Star of South Africa does not necessarily work within the climatic context of Ghana.
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Zohir Younsi, Lounes Koufi and Hassane Naji
A comprehensive investigation on the outlet air position effects on the thermal comfort and air quality has been achieved. In addition, airflow and temperature distributions in…
Abstract
Purpose
A comprehensive investigation on the outlet air position effects on the thermal comfort and air quality has been achieved. In addition, airflow and temperature distributions in ventilated cavities filled with an air-CO2 mixture with mixed convection are predicted. The airflow enters from the cavity through an opening in the lower side of the left vertical wall and exits through the opening in one wall of the cavity. This paper aims to investigate the outlet location effect, four different placement configurations of output ports are considered. Three of them are placed on the upper side and the fourth on top of the opposite side of the inlet opening. A uniform heat and CO2 contaminant source are applied on the left vertical wall, while the remaining walls are impermeable and adiabatic to heat and solute. The cooling efficiency inside the enclosure and the average fluid temperature are computed for different Reynolds and Rayleigh numbers to find the most suitable fluid outlet position that ensures indoor comfortable conditions while effectively removing heat and the contaminant. This is demonstrated by three relevant indices, namely, the effectiveness for heat removal, the contaminant removal and the index of indoor air quality.
Design/methodology/approach
The simulations were performed via the finite-volume scSTREAM CFD solver V11. Three different values of CO2 amount are considered, namely, 103, 2 × 103 and 3 × 103 ppm, the Reynolds number being in the range 100 ≤ Re ≤ 800.
Findings
Based on the findings obtained, it is the configuration whose air outlet is placed near the heat source and the contaminant, which provides a better air distribution and a ventilation efficiency compared to the others ventilation strategies.
Originality/value
The studies on heat and mass transfers by natural and forced convection in ventilated cavities remain a fruitful research topic. Thereby, such a study deals with different ventilation strategies through cavities containing an air-CO2 mixture subjected to a mixed regime. In particular, the air inlet velocity and contaminant sources’ effects on thermal comfort and air quality have been investigated.