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Background: Spiders are distributed worldwide except in Arctic and Antarctica. More than 45,700 species of spiders and 114 families have been identified. Spiders produce silk in order to capture their prey. reported that people of the Carpathian Mountains used spider webs from Atypus spiders as bandages. Experiments showed that silk from spider house is bio-degradable, non-antigenic and non-inflammatory. These are ideal properties for healing wounds. We aimed to identify the effect of spider threads on healing wounds and injuries compared to healing of wounds by application of tetracycline ointment. Methods: This is an experimental analytical study in which we investigated ten participants tested in three groups. Group A participants were treated with tetracycline and group B were treated with spider threads. wooden rulers used to collect spider silk threads along with sterilizer, tissue, paper, bandages, and Tetracycline ointment. Silk was collected from four types of spiders: Cellar Spider, Salticidae Spider, Venatoria Hetropoda, and Galeodes Arabs. These spiders are the mostly distributed in Sudan. Silk was collected by using wooden rulers from cracks and corners of walls at Alzaiem Alazhari University and then placed on clean, soft tissue paper. Results: revealed that spider threads heal surface injuries without leaving scars in 90% of participants. The healing process with spider threads lasts between 8 -24 hours. The comparison between three tests showed that the percentage of wound healing was highest by 70% by using spider threads in comparison with tetracycline and self-healing. Conclusion: It was observed that healing of injuries by using spider threads was 70% faster than healing by using tetracycline ointment. Self-healing was observed to be faster than healing by use of tetracycline ointment. [ABSTRACT FROM AUTHOR]

Developing countries in hot climate regions such as Saudi Arabia have witnessed rapid population growth, which has led to greater resource consumption as a result of the increased demand for new buildings. This research proposes a multi-objective evaluation of the potential green engineering solutions to conserve energy using a building within the ROSHN housing project, which is one of the mega projects in Saudi Arabia, as a case study for this paper with the aid of simulation software, taking into consideration the context of the sustainability concept. The results showed that traditional passive architectural design, whether courtyards or Mashrabiya, had the nearly greatest influence, with percentages ranging from −4% to −5.15% for varied parameters and designs compared to the base case energy usage. Furthermore, energy efficiency solutions for the building envelope's external insulation and finish system (EIFS) enabled a drop in the U-value that lowered energy usage to −5.40%. However, the wall insulation thickness beyond 300 mm in this system has no substantial influence on energy savings. This research's most clear finding is that a P2P system for PV panels on a district scale can supply enough energy to meet its needs after implementing the optimal strategy of the other proposed solutions. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) are important elements in the global strategy to tackle climate change; however, research often fails to sufficiently identify the range of barriers which affect their adoption. Taking Saudi Arabia as a case study, this paper analyses responses from 698 potential drivers in order to identify and rank the infrastructure, performance, financial, social, and policy barriers to EV adoption in a major oil-producing nation with a hot climate and a desert terrain. According to this study's findings, the most important barriers in this context are the lack of charging infrastructure and the additional load placed on the national grid, while others include the safety and effectiveness of batteries at high temperatures, and the ability of EVs to perform in desert conditions. Common themes also include concerns that EVs may damage Saudi's oil-based economy, cost of purchase and maintenance, low resale value, and the absence of awareness about EVs. The study concludes that EV manufacturers must demonstrate that their vehicles are suitable for the Saudi climate. Governments should also provide subsidies, or other incentives, to promote adoption of EVs as the study also found that variations in the cost of different EV models in Saudi Arabia, for example, the Tesla Model 3, is up to 40% more expensive to own than a Toyota Camry, mean that owning EVs can cost significantly more than small sized internal combustion engine-based vehicles (ICEVs). This paper identifies and ranks the barriers to EV ownership in a desert nation which is a leading petroleum producer and compares the relative costs of EVs and ICEVs in the country. As such, it has immediate relevance in countries with similar economic, geographic, and climatic conditions. [ABSTRACT FROM AUTHOR]

Summary: Microencapsulated phase change materials (MEPCMs) have made tremendous advancements in recent years, owing to their increased demand for a variety of energy storage applications. In this paper, current microencapsulation techniques, enhancement, and use of medium‐ and high‐melting phase change materials (PCMs) are reviewed, as well as their potential benefits and limitations. The most frequently employed PCMs for medium‐ and high‐temperature applications were recognized as salt‐based, metallic, inorganic compound, and eutectic. Meanwhile, polymethyl methacrylate (PMMA), polystyrene‐butylacrylate (PSBA), polyethyl‐2‐cyanoacrylate (PECA), and polyurethane were widely used as polymer shell materials for encapsulating medium‐ and high‐melting point PCMs via chemical method, whereas inorganic silica shell was synthesized via various techniques. Hydrolysis followed by heat‐oxidation treatment has been extensively studied since 2015 to encapsulate either metal or alloy within Al2O3 shells. Different techniques were developed to generate void between core and shell material to accommodate volume expansion during phase transition. Numerous approaches, including the incorporation of metal particles, carbon, and ceramic, have been found as ways to enhance the thermal performance of PCMs. Multiple storage arrangements were also established to be an effective way of enhancing the overall efficiency of medium‐high melting PCM storage systems. Finally, the paper highlights the potential of medium‐ and high‐melting temperature PCMs for solar power generation, solar cooking, and industrial waste heat recovering applications. [ABSTRACT FROM AUTHOR]

One of the important heating criteria of a greenhouse in the Northern hemisphere countries is heat availability, particularly in the winter season. Among other heat storage types, seasonal soil-based energy storage performance is auspicious. However, the performance is affected by the length and depth of borehole pipes used, which are very expensive for growers. Therefore, this study investigates the performance of a shallow seasonal soil-based energy storage heat pump, in a greenhouse. Thick insulations were installed to reduce soil heat loss. The soil thermal imbalance ratio was calculated to know the thermal recovery resulted. Based on the results, the heat pump's seasonal coefficient of performance (COP) heating and cooling varied between 1.48–2.97 and 1.20–3.45, respectively. The COPsys heating and cooling were observed to be 1.51 and 1.55, respectively. However, the system successfully maintained indoor temperature >16°C in other seasons, except for winter. Due to low brine input in winter, the average indoor temperature dropped to 11°C, indicating a thermal soil property problem. Moreover, the proposed system achieved soil thermal imbalance ratio of 32.76%. [ABSTRACT FROM AUTHOR]

The case study presented in this paper is an innovative ground source heat pump (GSHP) system constituted by a hybrid Photovoltaic Thermal (PVT) solar system for poultry houses. Farmers tend to not to apply GSHPs because of the high prices of excavation and time consumption. The innovative heat pump system assessed in this study comprises of a new type of heat exchangers; a thin-tube solar polyethylene heat exchanger installed between roof tiles and PV panels and a novel vertical ground heat exchanger to utilize the heat stored in the soil. The heating system applied to a poultry house are monitored and evaluated under a variety of environmental and operating conditions to achieve annual/long-term efficiency of the heating system in Kirton, UK. The maximum heating demand of the poultry house is determined 34.4 MWh/PC while the minimum is 11,1 MWh/PC. The monitored results show that the heat pump produced 15.02 MWh of thermal energy per annum. Solar PV and heat pump worked very well together with solar PV covering all the heat pump's annual electrical energy requirement and generated 8.74 MWh of extra electricity exported to the grid. The seasonal coefficient of performance is found 3.73 through a year. The novel PVT-GSHP heating system is a very promising solution for high fossil fuel consumption in the agriculture industry and the energy savings of the whole system can be noticeably increased dependent up on the system controlling. [ABSTRACT FROM AUTHOR]

Adsorption heating/cooling became an alternative to vapour compression system due to low ozone depletion potential (ODP) and global warming potential (GWP). However, more investigation is required due their low efficiency when compared to conventional heating/cooling systems. This review emphasizes on the mathematical modelling simplification and heat transfer enhancement method that applied by many researchers to improve the performance of adsorption heating and cooling technologies. Various techniques investigated by many researchers on solving low thermal conductivity and the different methods for enhancing heat and mass transfer in the adsorbed bed/pipe also discussed. Common techniques used to enhance heat and mass transfer in the adsorbed bed/pipe include the fin type adsorbent tube/ heat exchanger, amalgamated adsorbent bed with a metal foam, consolidated adsorbent, adsorbent coating and adsorbent with multi cooling tubes. Other than that, recent advancements in adsorption cooling/heating systems also discussed in this review. [ABSTRACT FROM AUTHOR]

Free Cooling based on Phase Change Materials (FCPCM) are promising sustainable technologies which aim to use the cold night ambient air as a heat sink. The stored cooling in the PCM could be used to offset the heat generated during the daytime. The current work aims to evaluate the feasibility of FCPCM technology in hot-arid regions where the cooling demand is dominant throughout most of the year. A PCM storage system comprising a number of PCM panels has been developed and assessed using Computational Fluid Dynamics modelling utilising ANSYS Fluent. The influence of operating conditions on the system performance was discussed by 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 maintained well within the summer comfort zone of 25.5 and 30°C under the case study climate for up to 14.5 h during the discharging period. However, the system performance is less efficient during peak summer conditions, and a combination with other passive cooling strategies may be required. [ABSTRACT FROM AUTHOR]

Despite the promise of abundant renewable energy resources in the world, the poultry sector is still dominated by traditional energy sources. In this study, results of a field trial of an innovative and cost-effective HVAC system design applied to a poultry house have been presented. This system comprises of two integrated novel components; a polyethylene heat exchanger (PHE) based a photovoltaic thermal (PVt) array and an efficient and innovative ground pipe array coupled to a heat pump driven HVAC system. The analysis included the daily PV electrical output and heat pump performance. The results of the experimental study reveal that 3733 kWh and 2432 kWh heat energy have been supplied in the 7-week growth cycle of chickens condition, respectively. The COP of the HP has been calculated for the winter period and observed between 2.3 and 2.43. The PV system was able to generate 1876 kWh electrical energy with potential to meet HP's energy needs in the most energy needing period. [ABSTRACT FROM AUTHOR]

Recent innovations in greenhouses for energy-saving purposes have included developments in heat-pump technology, semi-transparent Photovoltaic (PV), lighting technology, and control systems. In addition, retrofitting greenhouse with Light Emittance Diode (LEDs) can provide energy-saving lighting, which costs up to 75% less per year compared to the cost of other artificial lights. Moreover, combining heat pump and underground thermal storage could cut energy demands by 25%, and semi-transparent or checkerboard PVs on rooftops could simultaneously reduce the cooling energy demand and generate electricity. Finally, an automatic control system in greenhouses would both ensure energy efficiency and accurately control the microclimate within the greenhouse, resulting in suitable conditions for the crops. [ABSTRACT FROM AUTHOR]

A combined power and cooling system is proposed for cogeneration, which integrates the ejector cooling cycle with the Rankine cycle. Low-temperature heat source such as industrial waste heat or solar energy can be used to drive the Rankine cycle. This system will provide electricity and cooling effect simultaneously without consuming primary energy. The partially expanded vapor (from low-grade energy) will be bleed off and enter into ejector's primary nozzle, which achieves cooling effect. Simulations have been carried out to analyze the effects of various working conditions on the overall system performance, on ejector entrainment ratio and turbine power output. Five different refrigerants HFE7100, HFE7000, methanol, ethanol and water have been selected, and the above three parameters were compared, respectively. The simulation results indicated that turbine expansion ratio, heat source temperature, condenser temperature and evaporator temperature play significant roles on the turbine power output, ejector entrainment ratio and the overall thermal efficiency of the system. At a heat source temperature of 1208C, evaporator temperature of 108C and condenser temperature of 358C, methanol showed the highest thermal efficiency (0.195), followed by ethanol and water (0.173). It is recommended that the evaporator temperature and the appropriate working fluid should be selected according to the different working cooling requirements, and the turbine power output can then be determined accordingly. [ABSTRACT FROM AUTHOR]

Low carbon and renewable energy sources (RESs) are fast becoming a key sustainable instrument in meeting the global growth of electricity demand while curbing carbon emissions. For example, the gradual displacement of fossil-fuelled vehicles with electrically driven counterparts will inevitably increase both the power grid baseload and peak demand. In many developed countries, the electrification process of the transport sector has already started in tandem with the installation of multi-GW renewable energy capacity, particularly wind and solar, huge investment in power storage technology, and end-user energy demand management. The expansion of the Electric Vehicle (EV) market presents a new opportunity to create a cleaner and transformative new energy carrier. For instance, a managed EV battery charging and discharging profile in conjunction with the national grid, known as the Vehicle-to-Grid system (V2G), is projected to be an important mechanism in reducing the impact of renewable energy intermittency. This paper presents an extensive literature review of the current status of EVs and allied interface technology with the power grid. The main findings and statistical details are drawn from up-to-date publications highlighting the latest technological advancements, limitations, and potential future market development. The authors believe that electric vehicle technology will bring huge technological innovation to the energy market where the vehicle will serve both as a means of transport and a dynamic energy vector interfacing with the grid (V2G), buildings (V2B), and others (V2X). [ABSTRACT FROM AUTHOR]

This paper presents results of a thermal conductivity test carried out on microencapsulated phase change materials, to be used as a cooling storage and transport medium in a solar-driven air conditioning system. The microencapsulated slurries can be used not only as an energy storage medium but also as an energy transport medium, and this helps the system to be designed as compact as possible. The test has been carried out on two recently developed microencapsulated phase change materials. A convenient measurement system using transient line heat source technique is introduced, and the results of these measurements are presented in this paper. [ABSTRACT FROM AUTHOR]

The Kingdom of Saudi Arabia (KSA), as one of the largest polluters worldwide, has released its Vision 2030 that seeks sustainable development via economic diversification to transition towards lower CO2 energy systems. Due to fast population and economic growth, the Kingdom is undergoing an increasing volume of construction, which is projected to exacerbate the energy-related emissions. Strategies are needed to decarbonise the housing stock and help bridge the existing performance gap with the updated Saudi Building Code (SBC). This study proposes a holistic retrofitting approach for the Saudi building industry to facilitate the identification of energy consumption reduction optimisation solutions, covering the assessment of insulation, reflective coating surfaces, sun shading devices, efficient glazing solutions, building-integrated renewables, and green roofs. The proposed flexible approach proved how blended retrofit packages provide improved performance, with rooftop photovoltaic microgeneration and improved glazing technologies singlehandedly outperforming the remaining proposals for KSA's Riyadh climate conditions. Only the photovoltaic system could meet the simulated SBC performance benchmark independently, positioning it as an instrumental tool in improving the overall effectiveness of the retrofit packages. [ABSTRACT FROM AUTHOR]

It is widely believed that the incorporation of renewable energy to the current power grid is the way forward in achieving sustainable power generation. Currently, with the reduction of PV prices, many countries have started connecting PV systems into their grid network, hence leading to a sharp increase of the penetration levels of renewable electricity production. This will bring significant change in the load pattern and the ramping requirements of the grid's conventional generation system due to the varying nature of the renewable energy generation. This significant change affects the stability of the grid frequency because it becomes more challenging for the system operators to maintain the equilibrium between the generation and load. Additionally, this significant change affects the PV system potential hosting capacity of the traditional grid because of the PV system's curtailment in order to comply with the constraints of the grid's conventional generation system. In this paper, the net load, grid frequency stability, and grid potential hosting capacity are evaluated in the situation of increasing the penetration level of large-scale PV systems generation into the grid. The results show that the grid operators will face increasingly variable net load patterns and steeper ramping events as the PV system penetration level increases. Additionally, the results show the requirement of having flexibility measures that target each grid constraint as the PV system penetration level increases. [ABSTRACT FROM AUTHOR]

Decarbonisation, energy security and expanding energy access are the main driving forces behind the worldwide increasing attention in renewable energy. This paper focuses on the solar photovoltaic (PV) technology because, currently, it has the most attention in the energy sector due to the sharp drop in the solar PV system cost, which was one of the main barriers of PV large-scale deployment. Firstly, this paper extensively reviews the technical challenges, potential technical solutions and the research carried out in integrating high shares of small-scale PV systems into the distribution network of the grid in order to give a clearer picture of the impact since most of the PV systems installations were at small scales and connected into the distribution network. The paper reviews the localised technical challenges, grid stability challenges and technical solutions on integrating large-scale PV systems into the transmission network of the grid. In addition, the current practices for managing the variability of large-scale PV systems by the grid operators are discussed. Finally, this paper concludes by summarising the critical technical aspects facing the integration of the PV system depending on their size into the grid, in which it provides a strong point of reference and a useful framework for the researchers planning to exploit this field further on. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents theoretical investigations into a hybrid ejector and CO2 vapour compression (VC) system for road transport cooling. The purpose is to utilise the waste heat from exhaust gas and the VC sub-system to drive the ejector system, whose cooling effect will be employed to subcool the VC sub-system. Exploitation of the energy consumption ratio between ejector sub-system and CO2 VC sub-system indicated that the more energy obtained from exhausted gas, the better system performance could be achieved for CO2 VC sub-system, and hence higher cooling capacity of the VC sub-system at the same compression power. Thermodynamic simulations of two sub-systems and the hybrid system were presented. The results indicated that, at boiler temperature of 120°C, evaporator temperature of 10°C, a COP of 0.584 was achieved for hybrid system, with 22% improvement over a single ejector cycle. Preliminary experimental studies were carried out on a single ejector cycle, with boiler temperatures between 115°C and 130°C, and evaporator temperatures between 5°C and 10°C. The effects of various operation conditions on the overall ejector operation were coherently analysed. The COP of the ejector sub-system from experimental results was approximately 85% compared with simulation results, which showed a good agreement between theoretical analysis and experimental results. [Copyright &y& Elsevier]