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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.

Radiative cooling (RC) shows good potential for building energy saving by throwing waste heat to the cosmos in a passive and sustainable manner. However, most available radiative coolers suffer from low cooling flux. The situation becomes even deteriorated in the daytime when radiative coolers are exposed to direct sunlight. To tackle this challenge, an idea of employing both a spectrally selective cover and a spectrally selective emitter is proposed in this study as an alternative approach. A comparative study is conducted among four RC modules with different spectral characteristics for the demonstration of how the spectral profiles of the cover and the emitter affects the RC performance. The results under given conditions show that the RC module with a spectrally selective cover and a spectrally selective emitter (SC/SE) reaches a net RC power of 62.4 W/m2 when the solar radiation is 800 W/m2, which is about 1.8 times that of the typical RC module with a spectrally non-selective cover and a spectrally selective emitter (n-SC/SE). When the ambient temperature is 30 °C, the SC/SE based RC module realizes a daytime sub-ambient temperature reduction of 20.0 °C, standing for a further temperature decrement of 9.2 °C compared to the n-SC/SE based RC module.

Industrial processes and the building sector (e.g., for space and water heating) are responsible for the majority of the total energy consumed for heat. Although fossil fuels remain to dominate the heating sector, renewable heating technologies have been lately widely deployed. Thermochemical energy storage (TES) can be a promising advanced technology in addressing the mismatch between renewable energy supplies and the end-user’s demand. In this paper, a novel 'Vermiculite-based Solar Thermochemical Heat Storage' (VS-THS) system was proposed for domestic space heating applications, which could also overcome the intermittency challenges and realise long-term solar energy storage. A small-scale prototype was set up to evaluate the energy storage performance of the proposed system using a patented ChainStore panel to accommodate vermiculite-based composite. The unique design of the ChainStore arrangement offers great heat and mass transfer and good flexibility for system resizing in the case of varying the building energy demand. Due to the low regeneration temperature (63 °C) and high energy storage density (253.8 kWh/m3) of the vermiculite-based adsorbent impregnated with MgSO4 and CaCl2, it was chosen as the THS composite in the experiments. The experimental results showed that the proposed VS-THS is feasible for domestic space heating, with the highest space heating supply temperature of 37.6 °C, and the system COP in the reaction process is 7.9–10.4. In addition, the results also demonstrate that the composite of vermiculite impregnated with MgSO4 and CaCl2, with a good water adsorption performance. This proposed concept of VS-THS could be sized for different building applications.

Louvre is a common type of shading devices and has been increasingly used in office buildings. Meanwhile, some reflective types of louvre have been used to provide shade and to redirect daylight deep into buildings interior simultaneously. Furthermore, daylighting systems have been recently engaged with automation control to improve their performance and increase their accuracy. Accordingly, automation of a louvre can optimise daylighting performance, maximising visual comfort, and lighting energy saving. In order to maximise the benefits of daylight, these shading devices should be controlled efficiently using advanced control methods. On the other hand, one of the significant application in daylighting systems is the prismatic panel, which was used in several buildings to improve daylighting due to its easy installation, which also based on redirecting the light into the interior of the buildings, besides its reflective and refractive characteristic. This article presents a feasibility study on the combination of two advanced daylighting designs, i.e., prismatic panel and automated louvre, aiming to achieve simultaneous shading and redirecting daylight for better daylight distribution. In the proposed design, the louvre is comprised of prismatic slats, i.e., prismatic panel as slat. The prismatic louvre is implemented virtually based on an algorithmic system using parametric software Grasshopper, in order to control the automation process parametrically as a first step, and then the daylighting performance is simulated using Radiance as a plug-in to Grasshopper. The optical characteristics of the prismatic slats in an automated louvre is investigated. A comparison has been made in simulation between a prismatic panel and the automated louvres with reflective slats and prismatic slats, respectively, to evaluate their daylighting performance in a south-orientated virtual room in New Cairo. The simulation results are given for the conditions of clear sky on the 21st of June, 21st of September, and 21st of December.

TNottingham University, Department of his paper is intended to design and develop a thermal model of an integrated semitransparent thin-film PV vacuum glazing with four layers of glass called PV VG-4L. Correspondence to: Hasila Jarimi, The design of the glazing involves integration between a thin-film PV glazing with a double vacuum glazing both manufactured independently , and an additional layer of selfcleaning coated glass. For the mathematical model, the energy balance equations were derived for the thin-film PV glass, the glass panes of the vacuum glazing and the edges of the internal and external glass surfaces facing indoors and outdoors respectively . The model was numerically solved in MATLAB. To evaluate the performance of the PV VG-4L, the prototype was manufactured and investigated at lab-scale and also under real conditions. At lab-scale, experiments were conducted at steady-state conditions using a TEC driven calibrated hot box at Sustainable Energy Research Lab, University of Nottingham, UK. Meanwhile, outdoors, the prototype was tested at a research house at the University of Nottingham, UK. The developed model was then validated against the experimental results by direct comparison on the trend of the experimental and theoretical curves obtained, and also by conducting error analysis using root mean squared percentage deviation RMSPD method. When tested using the calibrated hot box, by following closely the ISO 12567 standards, the average measured total U-value is 0.6 W/m2K. From the analysis, the computed RMSPD value for the glazing surface temperature and the U-value are 4.75 % and 0.96% respectively. The RMPSD computed for the glazing surface temperatures, electrical power generated under real conditions and U-value are 2.58 %, 1.4% and 6.86 % respectively. The theoretical and experimental results are concluded to be in good agreement. The thermal and electrical performance of a building retrofitted with and without PV VG-4L was examined and discussed. At building efficiency level, the PV VG-4L not only can produce power, but it also has high insulating properties. The promising U-value implies that the glazing’s range of potential applications can be improved depending on the energy needs and applications, which includes its use in BIPV solar façades PV curtain walling for commercial buildings, greenhouses, skylights and conservatories

This paper investigates the transient performance of a DC compressor fridge incorporated with Phase Change Material (PCM) for weak/off-grid setting regions. A photovoltaics (PV) module is directly connected to the DC compressor without use of batteries and inverter, in order to simplify the system and reduce its cost. The DC compressor speed can be adjusted according to the radiation intensity for an optimum match between PV output and the efficiency of refrigeration. During the daytime, the PCM is charged for cold storage by refrigeration; when solar radiation is weak or during the night, the PCM releases cooling to maintain the required cabinet temperature. A transient mathematical model is built for the whole system including PV module, DC compressor refrigeration system, fridge cabinet and PCM packs. The model is coded and solved in MATLAB while CFD method is used to produce some additional information. The simulations are conducted to evaluate the effect of solar radiation intensity, thermostat setting and the number of PCM packs on the fridge refrigeration performance. Moreover, the study aims to investigate and present benefits of incorporating PCM with a direct PV powered DC compressor fridge in weak/off-grid setting areas. When the fridge cabinet temperature varies between 4℃ and –2℃, the average COP of the fridge refrigeration system was found 1.7 for high solar radiation day due to the high rotation speed of the compressor, but for low solar radiation day, the average COP was calculated as 1.95. The analysis also shows that a variable speed DC compressor can keep the foods in the desired temperature range for two days of power outage by using 1 m2 PV module and 3.6 kg of thin PCM packs.

I n this paper, a solar-driven power system as a means of meeting electricity demand in a small community has been investigated in terms of its transient performance on an annual basis. Using a sensible heat storage unit, the heat collected by evacuated flat plate collectors EFP can be stored and used at other times to feed an organic Rankine cycle ORC . The storage unit is analysed using a one-dimensional temperature distribution model including heat loss to the ambient. The stored heat in the unit makes it possible to produce electricity at night. In order to meet the electricity demand in all seasons, evaporation temperature is controlled by the present model via adjusting the water mass flow rate of the heat source. Solar ORC using EFP collectors is a promising technology but dynamic simulation on its annual performance has not been conducted yet. Investigation of the daily performance with consideration of transient behaviour of the components is the main aim of the study. The system performance is evaluated for different seasonal weather conditions. An 8-kW expander output is desired for the peak period which is in the evening for a small community, when sufficient solar irradiance is available. The system also operates in combined heat and power mode during the winter period to supply heat for space heating purpose. Results show that 23296.8 kWh electricity is produced considering the demand pattern during the year and 19344.7 kWh heat can be used for heating for the selected four months

A split louver consists of two sections with their slat angles to be adjusted separately for glare protection and redirection of sunlight, respectively. The upper section works in conjunction with the lower section to enhance daylight availability and uniformity throughout the year. The study aims to improve the daylighting performance of the split louver by applying a simplified parametric control, which predetermines the angle difference between adjacent slats in the upper section for a chosen solar altitude and then keeps this difference fixed during operation. The slats in the upper section can be changed parametrically using the Grasshopper to reflect daylight onto the ceiling and then illuminate the rear zone of a space. The lower section of the split louver can control the daylight in the front space area and may affect the amount of light in the back. The performance indicator in evaluating the proposed split louver design for the chosen typical days is the percentage coverage of the work plane area for the illuminance range of 150~750 lux, which was achieved up to 100% in some cases. The proposed split louver with the simplified parametric control has the potential to provide relatively consistent and distributed daylight coverage of the floor area and a glare-free environment.

In this study, we have investigated a hybrid thin film PV vacuum glazing called: ‘PV VG-4L’. The glazing involves an integration between a thin film PV glazing with a double vacuum glazing (both manufactured independently), and an additional layer of self-cleaning coated glass which totalling four layers of glass. The mathematical model of the PV VG-4L designs were developed and numerically solved in MATLAB. To evaluate the performance of the PV VG-4L, the prototype was manufactured and investigated at lab-scale and also under real conditions. Lab-scale experiments were conducted at steady state conditions using a TEC driven calibrated hot box at the Sustainable Energy Research Lab, University of Nottingham, UK. Meanwhile, outdoors, the prototype was tested at a research house at the University of Nottingham, UK. Under the influence of solar irradiance, the electrical performance of the PV-VG and the temperature difference between the surfaces of the glazing were analysed. However, the measurement of U-value under real conditions is not reliable due to the influence of solar irradiance on the heat flux sensor and also due to the absorbed solar irradiance by the thin film PV layer. Nevertheless, during low to zero solar irradiance, the U-value of the prototype can be estimated. The developed model was then validated against the experimental results by direct comparison to the trend of the experimental and theoretical curves obtained, and also by conducting error analysis using root mean squared percentage deviation (RMSPD) method. Testing using the calibrated hot box, adhering closely to ISO 12567 standards, resulted in an average measured total U-value of 0.6 W/m2K which is when compared to a single thin film PV glazing with a typical U-value of 5 W/m2K; the U-value is higher by almost 90%. From the analysis, the computed RMSPD value for the glazing surface temperature and the U-value are 4.02% and 0.92% respectively. Meanwhile, field testing under real conditions with a 0.4 m × 0.4 m PV VG-4L prototype found that 14 W/m2 power can be generated by the PV VG-4L at average solar irradiance of ~600 W/m2. RMSPD computed glazing surface temperatures, electrical power generated under real conditions and U-value are 2.90%, 8.70% and 2.89% respectively. The theoretical and experimental results are concluded to be in good agreement. This study has significant contributions to the knowledge of building integrated photovoltaic PV technology. The mathematical model that has been developed can be used for PV VG-4L design optimisation and also to simulate the performance of PV VG-4L under various conditions. At building efficiency level, the PV VG-4L not only can produce power, but it also has high insulating properties. The promising U-value implies its range of potential applications which can be improved depending on the energy needs and applications, such as for BIPV solar façade (PV curtain walling) in commercial buildings, greenhouses, skylight and conservatory.

Solar concentrating system is an effective way of combing solar energy with the building to satisfy the needs besides of electricity and hot water, also includes building heating, refrigeration, dehumidification, which require higher quality heat source. This paper put forward a novel static asymmetric lens-walled compound parabolic concentrator (ALCPC), which is composed of the mirror CPC and lens-walled structure, and can make full use of the total internal reflection and specular reflection. The optical performance of the ALCPC under the real application condition was established by software Lighttools®. Furthermore, the optimization structure by rotating the absorber away from the wall at some specific angles was also adopted for a wider scope applications. The results showed that the ALCPC has a large acceptance angle of 59° with highest optical efficiency of around 90% for most of the incident angles and has a relatively uniform flux distribution. In addition, annual performance analysis of the ALCPC was also done for Beijing (39°54’N, 116°23’E). The ALCPC as a static concentrator would be a good solution for the building south wall integration.

Radiative cooling (RC) is attracting more interest from building engineers and architects. Using the sky as the heat sink, a radiative cooling material can be passively cooled by emitting heat to the sky. As a result of the development of material technology, RC research has been revived, with the aim of increasing the materials’ cooling power as well as finding reliable ways to utilize it in cooling for buildings. This review identifies some issues in the current implementation of RC technologies in buildings from an architectural point of view. Besides the technical performance of the RC technologies, some architectural aspects, such as integration with architectural features, aesthetic requirements, as well as fully passive implementations of RC, also need to be considered for building application. In addition, performance evaluation of a building-integrated RC system should begin to account for its benefit to the occupant’s health and comfort alongside the technical performance. In conclusion, this review on RC implementation in buildings provides a meaningful discussion in regard to the direction of the research.

The efficiency improvement of household refrigerators is of significance to electricity consumption reduction of residential buildings. The cold loss recovery in household refrigerators is a promising development direction. In this study, a refrigerator improved by heat pipes is designed to reduce the cold loss at freezer walls to enhance the overall efficiency of the refrigerator. A complete steady-state mathematical model is built for characterizing its overall energy saving behaviors by introducing the real structural parameters of a Midea BCD-111 refrigerator and measured temperature boundary conditions. The performances of the improved refrigerator are investigated with typical operating states, variable ambient temperature, and heat pipe design. The simulative results indicate that the cold loss of the freezer of the improved refrigerator can be reduced by 8.3–16.5%, and the energy saving capability is relatively reliable. Results verify that the cold loss recovery of the improved refrigerator is feasible in various operating conditions.

This study presents a numerical validation of a new approach to model single junction PV cell under non-uniform illumination for low-concentration solar collectors such as compound parabolic concentrators (CPC). The simulation is achieved by finite element modelling (FEM). To characterize the results, the model is simulated with five different non-uniform illumination profiles. The results indicate that increasing the non-uniformity of concentrated light will introduce more resistive losses and lead to a significant attenuation in the PV cell short-circuit current. The FEM modelling results are then used to validate the array modelling approach, in which a single junction PV cell is considered equivalent to a parallel-connected array of several cell splits. A comparison between the FEM and array modelling approaches shows good agreement. Therefore, the array modelling approach is a fast way to investigate the PV cell performance under non-uniform illumination, while the FEM approach is useful in optimizing design of fingers and bus-bars on a PV.

Daylighting has a recognized potential for electric energy savings when is used as a complement for artificial lighting. This study reviews the comprehensive calculation method for lighting energy requirement in non-residential buildings introduced by the European Standard EN 15193: 2007 and investigates its feasibility in China. The location of building influences the intensity and duration of daylight. In EN 15193 calculation method, the daylight supply factor, which represents the effect of daylighting on usage of artificial lighting, is the only factor related to location and calculated according to latitude, however the current method (EN15193: 2007) limits the latitude range from 38° to 60° north in Europe, for which the relationship between daylight supply factor and latitude is approximately linear. This study shows that a quadratic relationship needs to be used for a wider range of latitudes. The coefficients of the proposed quadratic relationship are determined for the classified daylight penetration and maintained illuminance level. Various control types are also considered. Prediction of energy requirement for lighting is obtained through building simulation tool EnergyPlus and the effects of some setting factors are discussed.

In view of optimizing the configuration of each unit’s capacity for energy storage in the microgrid system, in order to ensure that the planned energy storage capacity can meet the reasonable operation of the microgrid’s control strategy, the power fluctuations during the grid-connected operation of the microgrid are considered in the planning and The economic benefit of hybrid energy storage is quantified. A multi-objective function aiming at minimizing the power fluctuation on the DC bus in the microgrid and optimizing the capacity ratio of each energy storage system in the hybrid energy storage system (HESS) is established. The improved particle swarm algorithm (PSO) is used to solve the objective function, and the solution is applied to the microgrid experimental platform. By comparing the power fluctuations of the battery and the supercapacitor in the HESS, the power distribution is directly reflected. Comparing with the traditional mixed energy storage control strategy, it shows that the optimized hybrid energy storage control strategy can save 4.3% of the cost compared with the traditional hybrid energy storage control strategy, and the performance of the power fluctuation of the renewable energy is also improved. It proves that the proposed capacity configuration of the HESS has certain theoretical significance and practical application value.

The air quality of indoor spaces is the most significant parameter in providing a healthy living environment. Low indoor air quality (IAQ) leads to Sick Building Syndrome—one of the major reasons for labor loss in office buildings. The fundamental measure to ensure indoor air quality is ventilation, which includes two basic types: mechanical ventilation and natural ventilation. Natural ventilation is an exchange of stale indoor air with fresh outdoor air by means of a pressure difference due to wind and/or stack effect. Trickle Vents, known also as background ventilators, are natural ventilation devices which can be integrated into façades or window systems as an alternative to operable vents, specifically in high-rise buildings. The major design criteria of Trickle Vents are ventilation capacity, controllability, actuation, thermal insulation, air permeability, water tightness, climatic adaptation, security, and acoustic attenuation. Other important parameters in Trickle Vents design are positioning, equivalent area, and control strategy. This paper aims to review all these aspects, particularly with reference to building regulations and commercial products. Furthermore, simulation, experimental, monitoring, and survey studies of Trickle Vents are also discussed. This literature review is presented from the perspective of performance parameters, control strategies, positioning, etc., with an aim to provide a comprehensive overview of such technology.

This study aims to determine the necessity of applying a mirror coating on the side of a truncated solid dielectric CPC (compound parabolic concentrator) since ray tracing analysis has revealed that part of the incoming rays do not undergo total internal reflection, even within the half acceptance angle of the CPC. An experiment was designed and conducted indoors and outdoors to study the effect of mirror coating on the optical performance of a solid dielectric CPC. Ray tracing was also employed for the detailed analysis and its results are compared with the measurements. Based on these, a concept of partial coating is proposed and verified through simulation. The results show that a partly coated solid dielectric CPC may have a better optical efficiency than a solid CPC without coating for a certain range of incidence angles.

Evacuated tube solar water heater systems are widely used in China due to their high thermal efficiency, simple construction requirements, and low manufacturing costs. CPC evacuated tube solar water heaters with a geometrical concentration ratio C of less than one are rare. A comparison of the experimental rig of evacuated tube solar water heater systems with and without a mini-CPC reflector was set up, with a series of experiments done in Hefei (31°53'N, 117°15'E), China. The first and second laws of thermodynamics were used to analyze and contrast their thermal performance. The water in the tank was heated from 26.9 to 55, 65, 75, 85, and 95 °C. Two types of solar water heater systems were used, and the data gathered for two days were compared. The results show that when attaining low temperature water, the evacuated tube solar water heater system without a mini-CPC reflector has higher thermal and exergy efficiencies than the system with a mini-CPC reflector, including the average and immediate values. On the other hand, when attaining high temperature water, the system with a mini-CPC reflector has higher thermal and exergy efficiencies than the other one. The comparison presents the advantages of evacuated tube solar water heater systems with and without a mini-CPC reflector, which can be offered as a reference when choosing which solar water system to use for actual applications.

This paper presented a novel solar collector that can work in air or water heating mode depending on the seasonal requirement. The dual-function solar collector (DFSC) integrated with a building as well as a reference building without the DFSC were built to test thermal behavior in passive air heating mode during winter. The buildings were equipped with an apparatus to control the room temperature. During the testing procedure, experimental study on the DFSC system was carried out under two conditions, where the indoor temperature was controlled and non-controlled. The results showed that the average temperature of the test room was about 3.43 °C higher than that of the reference room under the non-controlled condition. When the room temperature was controlled at 18 °C, the power consumptions of the test room and reference room were 4.322 kWh and 7.796 kWh, respectively. Consequently, the corresponding daily power consumption saved could reach up to around 3.5 kWh. Moreover, a dynamic numerical model on the DFSC along with the building was developed taking the fin effect of the Cu-tubes into account. The numerical results are found to be well consistent with the measured data. A parametric study on with/without Cu-tubes and depth of the air channel was carried out. It is found that the existing Cu-tubes functioning as water heating can enhance the air heating efficiency when the depth of air channel is of a suitable size.

Nowadays, daylighting systems and shading devices are controlled automatically to achieve their optimum benefits. For more comprehensive accuracy, parametric control was recently used to manage complex parameters with more accuracy. Such a system was proposed and investigated in a previous research to provide steadier and more uniform daylight illuminance during the day and reduce more than 80% of the electricity consumption. This study is examining the daylighting performance by using the parametric system in different orientations and comparing with the conventional ones. Furthermore, the study will evaluate the suitability of the parametric system throughout the year during the working hours in a typical office room.