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Solar thermal, photovoltaic, and radiative cooling are the three main methods to harvest solar radiation and universe coldness for building energy conservation and carbon-emission reduction. In this regard, the hybrid solar photovoltaic/thermal (PV/T) system is especially favored because of its compact structure and high energy efficiency. However, most buildings have dynamic cooling and heating demands related to climate zones and seasonal fluctuations, which can compromise the year-round efficiency of single-mode devices (i.e. heating or cooling alone). Herein, a hybrid solar photovoltaic/thermal-radiative cooling system (PV/T-RC) was proposed for the dynamic thermal management of buildings by enabling the system to switch between heating and cooling modes according to seasonal weather changes while providing year-round renewable electricity for buildings. The PV/T-RC system consists of a PV/T module and an RC module that is distributed to the sunny and dark sides of the roof, respectively, to boost the heating, electricity, and cooling output. An inorganic geopolymer radiative cooling (IGRC) coating was synthesized to fabricate the RC module, which could achieve a solar reflectivity of 94.9 % and broadband infrared thermal emissivity of 0.93. Theoretical analysis indicates that distributing the PV/T module and RC module on the south and north sides of the roof can effectively increase the year-round output of the heating/cooling energy and electricity. The field tests in Hong Kong showed that in the cooling mode, the RC module achieved a maximum daytime subambient cooling effect of 2.4 °C, which is 22.2 °C lower than that of the reference roof, and it reduced the indoor air temperature by 7.2 °C. While in the heating mode, the temperature of the PV/T module is 8.1 °C higher than that of the reference roof, increasing the indoor air temperature by 2.7 °C. The annual prediction results demonstrated that the PV/T-RC system can provide continuous heating, cooling, and electricity for buildings in regions with hot summers and cold winters. • A novel hybrid PV/T-RC system was proposed for year-round energy-saving. • The system can switch between solar heating and radiative cooling modes. • It reduced the indoor air temperature by 7.2 °C under cooling mode. • It increased the indoor air temperature by 2.7 °C under heating mode. [ABSTRACT FROM AUTHOR]

• Transmitting lens-walled compound parabolic concentrator (TLWCPC) as skylight. • The smart daylighting control potential of TLWCPC was analyzed and validated. • The effects of the orientation direction and inclination angle were analyzed. • The annual smart daylighting control performance in five cities was investigated. Regulation of solar transmission through windows offers the potential to reduce energy consumption in buildings. Recently, the daylighting control characteristic of optical concentrators have drawn considerable research attentions owing to their variable transmittance in response to sun motion. In this research, we aim to propose and validate a novel way to smartly regulate the indoor daylighting environment while generating renewable electricity generation at the same time through the concentrating photovoltaic/Daylighting (TLWCPC-PV/D) skylight. This research particularly focuses on the evaluation of smart daylighting control (SDC) performance of it. The optical model of the TLWCPC-PV/D skylight was built with using ray-tracing simulation technique, which is also validated by experiment results. Because of the variable optical concentration process, the TLWCPC shows obvious SDC characteristic: when –32°＜ θ ＜32°, average daylighting efficiency is 11.15% while when −43°≤ θ ≤ –32° and 32°≤ θ ≤ 43°, average daylighting efficiency is 58.89%. Five cities with different latitudes are selected to perform the yearly daylighting control analysis. The comparative results indicated that orientation direction has an essential impact on SDC characteristic of the TLWCPC-PV/D skylight and the system in the North-South orientation shows excellent SDC ability i.e. it shows larger daylighting efficiency during the early morning and later afternoon periods while maintains lower daylighting efficiency during the noon period. Compared with other complex and expensive energy-saving glasses, the TLWCPC-PV/D skylight smartly adjusts the solar transmission through the optical concentration process according to sun motion and offers a new strategy of easy fabrication and multi-energy use that opens avenues for both static solar concentrator design and SDC mechanism in energy-saving buildings. [ABSTRACT FROM AUTHOR]

• The effects of radiative cooling coating (RCC) on the metal container office were investigated through long-term field tests and numerical investigation. • RCC reduced the metal container office's surface temperature by 18 ℃ and saved 23.5% of electricity consumption. • RCC achieves cooling load saving rates of 22%-65% in different climatic regions. • RCC also brings heating load penalty rates of 7%-36% in different climatic regions. Radiative cooling coating (RCC) embedded with randomly distributed particles is a scalable, cost-effective, and reliable material that can enhance the energy efficiency of the building envelope. Many RCC materials with excellent cooling potential have been developed recently. However, there is a lack of holistic experimental and numerical demonstrations of RCC's energy-saving potential in real-world applications. In this research, by randomly distributing commonly used functional fillers into a polymeric matrix, an RCC material was developed and applied to an in-service metal container office at a construction site in Hong Kong. Parallel tests were conducted using another identical container office with a conventional white coating for comparison. The inner and outer surface temperatures of the two container offices, their indoor air temperature, and the electricity consumption of their air-conditioner system were measured and compared. The field-test results indicated that the RCC could reduce the container office's surface temperature by up to 18 ℃ and save 23.5% of electricity consumption under Hong Kong's climate compared to the conventional white coating. Furthermore, the numerical simulation model for the metal container office was developed in EnergyPlus and validated by the experimental results. Then, the simulation model was used to evaluate the overall energy-saving performance of the RCC in five different climatic regions in China considering different solar reflectivity values. It was found that in tropical or subtropical cities such as Hong Kong, with the solar reflectivity of the RCC increasing from 85% to 95%, the annual energy load saving rate increases from 19.2% to 30.9%. In other climatic regions, the increase in solar reflectivity will bring a significant increase in the heating load penalty that outweighs the cooling load savings. Therefore, in regions with hot summers and cold winters, optimizing the solar reflectivity of RCC by considering the offset between the cooling load saving and heating lead penalty is highly desirable in order to achieve the best annual energy-saving performance. [ABSTRACT FROM AUTHOR]

• An asymmetric concentrator with a large acceptance range of 10°–85° and high optical efficiency has been designed. • An multifunctional asymmetric concentrator-PV type window was designed. • The shading effect was analyzed and an optimization strategy was proposed to reduce the influence of it. • An typical office room integrated with the multifunctional asymmetric concentrator-PV type window was modelled and analysed. • The daylighting performance and concentrating PV performance were analyzed. The development of PV type window for building south wall integration is a promising concept, which provides a solution to the energy crisis and environment pollution problem. Thus in this paper, an asymmetric concentrator is proposed, and through the simple concentrator array optimization process, the asymmetric concentrator-PV type window can be designed, which provides the electricity generation and incorporates the function of daylighting at the same time. The optical models for the concentrator design and daylighting analysis are built and experimentally validated. The optical performance of the asymmetric concentrator has been analyzed. Considering that the incidence angles of sunrays on the building south wall remain at a high level throughout the year, the shading effect should be seriously considered. In order to reduce the shading effect between each concentrator array, the shading effect has been predicted and an arrangement optimization strategy by setting gaps between each concentrator array is presented. It was found that these gaps could alleviate the shading effect, which will also further allow the function of daylighting. Through the simulation analysis, it was found that the asymmetric concentrator can attain a large acceptance range of 10°–85° while maintaining high optical efficiency and the asymmetric concentrator-PV type window can achieve the daylighting efficiency of 4.0% to 21.8%, thus it can confirm good annual concentrating PV and daylighting performance. At last, a typical office room (the length, width and height are 3.4 m × 3.0 m × 3.3 m) installed with the asymmetric concentrator-PV type window is modelled and the illuminance distribution on the ground floor at various incidence angles is determined with the solar irradiance set at 500 W m−2. Besides of that, the energy distribution for the electricity generation and daylighting at various incidence angles is also indicated. Through the analysis, the asymmetric concentrator-PV type window is proved suitable for building south wall integration, which can efficiently use the solar energy for the domestic use, in the forms of electricity and daylighting. [ABSTRACT FROM AUTHOR]

Radiative cooling is a passive cooling method, which pumps the waste heat of terrestrial objects to the cold universe. Although much effort has been devoted to radiative cooling, the understanding of cooling properties should be further improved. This paper presents some considerations for radiative cooling to strengthen the understanding of the mechanism. First, it is generally recognized that the broadband cooler can get a higher maximal cooling power and the selective cooler can achieve a maximal temperature reduction, but this characteristic will be destroyed by non-radiative heat transfer between the cooler and surroundings, which means broadband materials will outperform selective materials across the board, violating the general viewpoint. Second, the maximal temperature reduction of the grey body cooler is independent of emissivity when the non-radiative heat transfer process is suppressed, indicating that only using maximal temperature reduction can not fully reflect the real cooling performance of the grey body cooler. Third, the thermal requirement of the potential applications should be highly considered during material design. If improving heat dissipation is always needed, the broadband cooler is the best choice. Otherwise, radiative cooler with dynamic emissivity modulation is the better one to adjust the dynamic requirement of heat dissipation and insulation. [ABSTRACT FROM AUTHOR]

• The design and performance comparison of a novel use of the concentrator to achieve the multifunction of the electricity generation and daylighting;. • The prototype of the concentrators are manufactured and the outdoor overall concentrating photovoltaic/daylighting experiment system was built;. • Optical performance of the concentrator was analyzed through the ray-tracing simulation and indoor experiment under the solar simulator;. • The actual transmittance of the system was investigated through the outdoor experiment under different sky conditions. This paper aims to validate an efficient way to use the low-concentration ratio concentrator for the building integrated concentrating photovoltaic/daylighting system, which is able to collect maximum solar energy for the renewable electricity generation and provide the function of daylighting. A 2-D static concentrator has been designed by leaving the lower portion of the outer parabolas near the base area uncoated to form the "daylighting window", which is named as CPVD (indicating that the concentrator is for the concentrating photovoltaic/daylighting system), while the concentrator with the same structure but can only achieve the onefold function of the electricity generation is named as CPV. In order to address the interaction effects between the concentrating PV performance and daylighting performance, the overall detail comparison is made for the CPVD module and CPV module through the ray-tracing simulation and experimental characterization. It's found that CPVD and CPV have similar optical performance (indicated by concentrating PV performance, optical efficiency, opto-electric gain and flux distribution on the receiver etc.) at various incidence angles, which validates that setting the "daylighting window" have no native effects on the optical performance of the concentrator. At last, in order to quantify the beneficial harvest for the daylighting, the conducive lighting transmittance through the "daylighting window" under two different sky conditions: clear and overcast sky conditions are investigated through the outdoor experiments. The outdoor concentrating photovoltaic/daylighting experiment test rig is built and the transmittance of the CPVD is measured under two different sky conditions. Under the clear sky condition, the daily average transmittance of the CPVD is measured to be 8.73% which is pretty much consistent with the ray-tracing simulation results. Under the overcast sky condition, the transmittance value is lower, the daily average value of which is 7.11%. [ABSTRACT FROM AUTHOR]

• The design of a novel CPV/D window based on the lens-walled CPC. • The comparison of the optical performance was made for the CPV/D and CPV module experimentally. • The daylighting simulation model in RADIANCE was experimentally validated. • The daylight performance of the CPV/D window was investigated. Daylight plays an important role on the environmental comfort level for buildings. As for the energy consumption in the building, lighting is one of the main contributors. However, traditional building integrated solar utilization systems such as flat photovoltaic or concentrating photovoltaic systems can only supply the heat or the electricity for buildings. Thus, a novel concentrating photovoltaic/daylighting window is proposed as a strategy to effectively generate the renewable electricity for the domestic use while providing a better daylight performance. The indoor experiment and ray tracing simulation are both conducted to identify the effect of the "daylighting window" on the optical performance of the concentrator. The annual daylight performance of a typical office building installed with the concentrating photovoltaic/daylighting window at various installation angles, window-to-ceiling ratios and under different climate conditions is investigated through RADIANCE. The accuracy and confidence of the simulation model is validated through the outdoor experiment, and the deviation between the experimental and simulation results is as low as 8.7%, which is indicated by the coefficient of variation of the root mean squared error. The simulation results show that the concentrating photovoltaic/daylighting window provides a good daylight performance on the working plane of the office room: the percentage of the working hours under daylight that lies in the useful range (100–2000 lx) can be up to 92.00%. It also achieves a homogenous distribution of daylight within the internal working space and effectively reduces the possibility of glare. Through the simulation results under different climate conditions, besides of the solar irradiance, the latitude also has an obvious effect on the annual daylight performance. So for the application in different latitudes, it's highly recommended to be installed with the inclination angel near the local latitude for a higher annual electricity output and better annual daylight performance. [ABSTRACT FROM AUTHOR]

Abstract A novel concentrating photovoltaic/daylighting window to achieve the multi-function of the electricity generation and daylighting for buildings has been designed, constructed and experimentally characterized. It's found that the concentrating photovoltaic/daylighting window can achieve a transmittance of around 10% for the natural daylight without decreasing the optical efficiency of the concentrator. The overall daylighting and electrical performance of the concentrating photovoltaic/daylighting window are investigated under the real weather condition. The hourly illuminance level, the temperature of the inner environment of the box and transient I–V curves are determined. The short-circuit current, open-circuit voltage, maximum power generation, and Fill Factor of the system are derived from each individual I–V curve. Through the experiment testing, the illuminance level in the integrating box is in the range of 923–9230 lx with the outside illuminance level exceeds 100000 lx during noon time, which proves that the concentrating photovoltaic/daylighting window can improve the visual comfort for the building interior environment and it can also avoid the building interior environment from overheating and dazzling at noon which is caused by direct sunlight through transparent window. The preliminary economic analysis of the new concentrating photovoltaic/daylighting window is also made. Highlights • The design of a novel Concentrating Photovoltaic/Daylighting (CPV/D) window based on the lens-walled CPC. • The prototype of the CPV/D window was manufactured and assembled for the outdoor experiment. • The overall daylighting and electrical performance of the CPV/D window was investigated under the real weather condition. • The preliminary economic analysis was made. • The experiment results prove good daylighting and electrical performance of the CPV/D window. [ABSTRACT FROM AUTHOR]

Highlights • A novel Concentrating PV/DC system is proposed for building application. • The concept of combining daylighting and PV system is presented. • Indoor experiment is conducted to validate the optical model. • The actual performance analysis of the CPV/DC system under real weather conditions is presented. • The CPV/DC system can be optimized for different building rooftop designs. Abstract A wide range of developed and commercially available daylighting systems have been reported, however, they have just a single function, so they require an extra complex component to adjust daylighting intensity to create a better visual-comfort interior environment seasonally. Thus, in this paper, a novel concentrating photovoltaic/daylighting control system based on the lens-walled compound parabolic concentrator which is made by the transparent material is proposed. It combines both PV and daylighting control for green building design. At noon, when the incidence angle is small and the solar radiation is strong, the majority of the solar radiation can be collected by the PV cell for electricity generation and the remaining solar radiation will act as the daylighting source. In the morning or evening, when the incidence angle is large and the solar radiation is weak, the majority of the solar radiation will pass into the building for daylighting while the remaining solar radiation will be collected by the PV cell for electricity generation. An optical model was built for the ray-tracing simulation by using the commercial software Lighttools®. The prototype of the lens-walled compound parabolic concentrator was manufactured and assembled for the indoor experiment to validate the optical model. To prove the feasibility of the system, the optical and electrical performance of the proposed concentrating photovoltaic/daylighting control system are derived from the simulation and experimental results, and the actual all-day daylighting performance of it is investigated through the software simulation. The simulation and experimental results indicate good electrical and daylighting performance of the concentrating photovoltaic/daylighting control system, and the proposed concentrating photovoltaic/daylighting control system suits all kinds building rooftop designs with different inclination angles, which proves it a wide scope of application. [ABSTRACT FROM AUTHOR]

The uniform illumination profile that falls on the PV cell is good for PV output and lifespan, however the flux distribution of the concentrating PV appears to be non-uniform in most cases which is harmful for the overall performance of the concentrating photovoltaic. In order to overcome this disadvantage, a novel asymmetric compound parabolic concentrator concentrating PV with uniform flux distribution is proposed in this paper. A two-dimensional finite element model is built for electrical performance simulation of the concentrating photovoltaic module. The prototype of the concentrating photovoltaic module is manufactured and assembled to conduct the indoor lab experiment under Standard Test Condition to verify the feasibility and reliability of the model. The outdoor experiments are conducted to show the electrical performance of the concentrating photovoltaic module under the real weather condition. Then the model is used to analyze the electrical performance of the PV cell under the flux distribution created by the proposed concentrator. The results show that the electrical performance of the proposed concentrating photovoltaic module is close to that under the uniform flux distribution with the same total radiation level, which confirms that the proposed concentrator is beneficial for the PV output under concentrating illumination due to uniform flux distribution. [ABSTRACT FROM AUTHOR]

Low-concentration PV (CPV, concentrating photovoltaic) technology is a promising concept because it can work with the fixed installation. However, besides the economic consideration, the environmental impacts of the CPV module throughout its life cycle should be addressed as compared with the flat PV technology. Thus, in this paper, a novel high optical performance low-concentration concentrator namely asymmetric compound parabolic concentrator (aCPC) for building south wall integration is proposed. And based on the proposed aCPC-PV module, a life cycle assessment (LCA) has been performed for the low-concentration PV in China to make a scientific comparison with the PV module with the same output level environmentally. Several environmental indicators are calculated for Beijing, Hefei, Lhasa, Lanzhou, Harbin. The primary energy demand, energy payback time and environmental impacts are considered over the entire life cycle of the aCPC-PV module. The results show that the primary energy demand, energy payback time and environmental impacts of the aCPC-PV module are all relatively lower than that of the PV module with the same output. It is confirmed by the LCA study that the aCPC-PV module on behalf of the low-concentration PV technology is still a feasible and effective way for actual engineering because it’s more economic and more environmental friendly than the PV technology although the PV is experiencing continuous decrease in price and increase in efficiency. [ABSTRACT FROM AUTHOR]

Concentrated photovoltaic (CPV) technology as a typical PV application is becoming popular due to its advantages of high conversion efficiency and low cost etc. However an important issue for CPV technology is the non-uniformity on the illumination and the temperature which can finally influence the overall electrical efficiency of solar cells. This study presents the feature of the non-uniform illumination and temperature, and reviews the cause and harm of the non-uniform illumination and temperature. Then the specific effect on cell parameters of different solar cells is analyzed, and finally the improving methods for reducing this negative effect on concentrating solar cells are proposed. This review will help researchers to learn the effect of the non-uniformity on the illumination and the temperature, and common improvement method, which will benefit CPV design and optimization. [ABSTRACT FROM AUTHOR]

A novel asymmetric lens-walled compound parabolic concentrator (ALCPC) for integration with the building south wall was proposed and manufactured. Besides of the asymmetric lens-walled structure, the special rotation angle at the bottom is also introduced to optimize the performance. The electrical and optical performance of the ALCPC-PV was detailed analyzed through the experiment and ray tracing simulation. The indoor experiment was conducted by a solar simulator (Oriel Sol3A Model 90943A) from Newport Corporation at the dark environment with the temperature of 25 °C. Form the experiment results, the ALCPC increases the maximum power by a ratio of 1.74x compared to the bare cell. The decrease of the geometric concentration ratio is mainly due to manufacturing errors, mismatch losses, series resistance losses, etc. The optical performance of the ALCPC was also investigated by the software Lighttools, and the optical efficiency and the distribution percentage of the energy collected through the total internal reflection and the specular reflection at different incidence angles are identified at various incidence angles. A good agreement is observed between the experiment results and the ray tracing results. The optical efficiency at the incidence angles of 0–60° is all within 90% of its peak value which means that the proposed ALCPC can achieve 60° acceptance angle with high optical efficiency that it shows a good potential as a static concentrator for the building south wall integration. [ABSTRACT FROM AUTHOR]

• A semitransparent energy-saving glass (SESG) is proposed for hot-climatic regions. • The maximum temperature reduction of the indoor air with SESG is 19.1 ℃. • The annual energy-saving potential reaches 15% —60% under different glazing ratios. • A more efficient balancing between the energy behavior and daylighting quality can be obtained. Glass-made building envelopes play an essential role in buildings' thermal/daylighting environment and energy behavior. To enhance its overall energy efficiency in cooling-dominated regions, a double-layer film that combines the concepts of selective solar utilization (SSU) and radiative cooling (RC) is proposed to form the semitransparent energy-saving glass (SESG). The SSU film (∼0.1 mm) is a multilayer optical film that contains polyethylene terephthalate (PET) and thin reflective metal layer. The RC film (∼0.1 mm) consists of a PET layer and an adhesion layer. To evaluate the daylighting, thermal, and energy-saving performance of the SESG on buildings, comparative field tests using reduced-size model boxes and whole-building energy simulation analysis on a larger-scale office building are conducted. Compared with the normal clear glass, the developed SESG decreases the indoor air temperature of the modeled box by maximum values of 19.1℃ and 17.8℃ while reducing the daylighting level by 68 % to support a more comfortable thermal/daylighting environment. In addition, a single-story office building modeling using EnergyPlus was developed to evaluate the energy-saving and daylighting performance of the SESG in two different cooling-dominated cities, Male (Maldives) and Hong Kong (China) considering different glazing ratios. Compared with normal clear glass which will add amounts of extra cooling load and cause serious glare problems due to its high transmittance to visible light and near-infrared solar radiation, the annual cooling energy savings of the SESG reach 15 %—60 % in two selected cities under different glazing ratios. By considering both energy-saving potential and daylighting quality, the simulation results show that in Male, within the glazing ratios of 0.4 to 0.6, the UDI (Useful Daylighting Illuminance) values and energy-saving potential both reach the highest value of 0.5–0.6 and ∼ 55 %. In Hong Kong, the UDI values and energy-saving potential both reach the highest value of 0.4–0.5 and ∼ 57 % when the glazing ratio ranges between 0.5 and 0.9. The experimental and simulation results validate that combining selective solar utilization and radiative cooling for the glass envelopes is able to seek a more efficient balance between the energy behaviors and daylighting environment for buildings in cooling-dominated regions. [ABSTRACT FROM AUTHOR]

This paper proposes a systematic design and formation process for the asymmetric compound parabolic concentrator taking the angular acceptance range as the target function and a dielectric asymmetric compound parabolic concentrator (DACPC) that presents almost unity angular acceptance efficiency is got. Ray-tracing simulation and experimental characterization study were conducted to reveal the optical performance of the DACPC. It was found that the DACPC with the geometric concentration ratio of 2.4 increased the short-circuit current and the maximum power by 87.0% and 96.6% averagely within the incidence angels of 0°–85° as compared with the non-concentrating photovoltaic cell. Corresponding average simulation and actual optical efficiency of it are 93.3% and 77.9%. The angular acceptance efficiency is proposed to evaluate the annual performance potential and regional applicability for optical concentrators, which indicates that the angular acceptance efficiency of the DACPC can be up to 97.7% for simulation results and 94.4% for experiment results. The outdoor experiments on 25th June when the projected incidence angle lied in the range of 60°–89° for the DACPC were conducted. It was found that the DACPC can still increase the short-circuit current and maximum power of the photovoltaic cell by average factors of 57% and 76% respectively. • The formation process of the DACPC was introduced. • Angular acceptance efficiency was developed to predict annual performance of DACPC. • The indoor and outdoor experimental researches were performed for the DACPC-PV. • Angular acceptance efficiency of the DACPC can be up to 97.7%. [ABSTRACT FROM AUTHOR]

• The novel TSCPC-PV/D outdoor experimental system was established. • Experiments on daylighting performance under different weather conditions were made. • The transmittance properties of the TSCPC-PV/D system were characterized. • TSCPC-PV/D system obtains a transmittance of 8% under different weather conditions. Compared with the PV electricity generation alone system, the hybrid photovoltaic/daylighting system is more efficient and more economical for the building application. In this paper, a novel self-regulating concentrating photovoltaic/daylighting system is proposed. Because the concentrator is made of the transparent material, the daylighting function can be efficiently incorporated without decreasing its optical efficiency. The transmittance characteristic of the concentrating photovoltaic/daylighting system is a vital parameter that is related to the electrical and daylighting performance of it, which also has a significant impact on the building's energy consumption behavior. To address this issue, the experimental investigation of this new system towards the visible light transmittance in different seasons and under different weather conditions is presented for the first time. The transmittance evaluation method based on the integrating box is adopted for the experimental test. The experiments are conducted on four different days that are corresponding to different seasons and different weather conditions. The conversion factor of the integrating box is first experimentally calibrated. The internal illuminance on four walls of the integrating box and the external illuminance are obtained, based on results of which, the transmittance of the concentrating photovoltaic/daylighting system is determined. It's found through experimental results that under the sunny weather condition in the summer, autumn, and winter seasons, the daily average tested transmittance of the concentrating photovoltaic/daylighting system is 8.57%, 6.78%, and 7.43% respectively. The experimental results under the overcast weather condition indicate that the transmittance of the concentrating photovoltaic/daylighting system for the diffuse solar irradiance is 7.22%. [ABSTRACT FROM AUTHOR]

This paper aims to present a novel concentrator-photovoltaic window (CPVW) for the building application, which is able to provide a uniform daylighting environment. In order to study the daylighting performance of the CPVW, the ray-tracing simulation model for the complex window systems are built and validated by the outdoor experimental results. The daylighting uniformity of the proposed window system is analyzed and compared with the state-of-the-art semi-transparent photovoltaic window system (STPVW). The coefficient of variation (CV) is developed to evaluate the daylighting uniformity of photovoltaic windows. It was found that with the use of the CPVW, the daylighting uniformity can be significantly enhanced, while enlarging the active daylighting area at the same time: the CV values are decreased from 0.647, 0.642, 0.606, 0.595, 0.639, 0.624, 0.764 (for the STPVW) to 0.011, 0.044, 0.054, 0.054, 0.113, 0.171, 0.220 (for the CPVW) at various incidence angles. Due to the sun rays reallocation of the concentrator, the active daylighting area can also be enlarged: the ratio of the active illumination area offered by the CPVW to that by the STPVW can be up to 6.69 ×. Thus, with the use of the concentrator-photovoltaic window system on the building, not only can the solar energy utilization be greatly enhanced and does suit the building energy demands well, but also it improves the daylighting uniformity and active natural daylighting area significantly. • A novel concentrator based multi-functional BIPV window was introduced. • The daylighting performance of the concentrator-PV window was investigated through validated ray-tracing simulation modell. • The concentrator-PV window can provide much more uniform daylighting environment. • The concentrator-PV window can illuminate as larger area as up to 6.7 times of its own size. [ABSTRACT FROM AUTHOR]

• It summarizes the building integrated solar concentrating systems according to different functions. • It introduces the demands, types, applications and structures of the building integrated solar concentrating systems. • It presents prospects/directions/policies around the world towards the building integrated solar concentrating systems. In the building sector, concerns towards the vast energy consumption has promoted the development of renewable energy technologies. In this regards, the solar concentration devices show a promising concept for building applications. However, the solar concentrators for application in buildings have many restrictions, which are different from the traditional solar concentrators. The main objective of this paper is to present a concise review on the building integrated concentrating devices, that have their own characteristics and multiple functions. This paper made a classification based on device's functions, i.e. building integrated concentrated photovoltaic systems (BICPV), building integrated concentrating solar thermal (BICST) and building integrated concentrating solar daylighting (BICSD) and the combination of functions, i.e. BICPV/T, BICPV/D, BICST/D and BICPV/T/D. At the same time, this paper presented an elaborate introduction of the demands, types and applications of the building integrated concentrating devices and prospects/ directions/ policies about these technologies around the world. The review would provide important information for the actual engineering of building integrated concentrating devices. [ABSTRACT FROM AUTHOR]

• A low-concentration PV module with different finger numbers is established. • The optimal number of fingers is determined. • Three low-concentration PV modules with different fingers spacing are established. • The optimal finger spacing is determined. • The influences of shading losses, finger resistance and lateral spreading resistance are analysed. Compared with conventional silicon solar cell, concentrating photovoltaic cell has a higher incident illumination intensity and non-uniform illumination intensity distribution. There is a close relationship between the illumination intensity and the resistance and shading losses of front metal fingers. In this paper, according to the non-uniformity of the illumination distribution formed by the concentrator, the effects of different finger numbers and spacing on the performance of low-concentrating photovoltaic cells were studied. First, low-concentrating photovoltaic cell modules with different finger numbers and spacing were established, and efficiency of these modules was compared to determine the optimal finger numbers and spacing of the front metal fingers. Then, effects of the shading losses, finger resistance and lateral spreading resistance on the performance of the low-concentrating photovoltaic cell were analyzed. Results show that for the specific illumination intensity distribution of the low-concentrating photovoltaic cell when the numbers and spacing of the front metal fingers are optimized, efficiency of the low-concentrating photovoltaic cell can be increased from 13.805% to 13.837%. Additionally, it can be concluded that the optimization of the number and spacing of the front metal fingers in the crystalline silicon solar cell is an efficient way to improve the electrical performance of the concentrating photovoltaic cell. [ABSTRACT FROM AUTHOR]

Harvesting energy from the hot sun and the cold universe is being investigated and has attracted much attention due to its clean utilization. Herein, a broadband selective absorber/emitter (BS-A/E) is designed and fabricated for the hybrid utilization of diurnal solar thermal and nocturnal radiative cooling. The BS-A/E exhibits high photon absorption in the solar band (i.e., 0.3–3 μm) with a weighted solar absorption of ∼0.83, a strong thermal emission mainly within the atmospheric window (i.e., 8–13 μm), and a low thermal emissivity in other infrared wavelength bands. The outdoor experiment demonstrates that the stagnation temperature of the BS-A/E is 11.6 °C greater than black paint under sunshine and 0.6 °C lower than that of black paint under darkness, showing considerable solar thermal and radiative cooling performance. In addition, thermal prediction also reveals that the BS-A/E can not only achieve solar heating during the day but also obtain sub-ambient cooling phenomenon during the night, indicating that the BS-A/E is capable of providing continuous heating and cooling for humans in various potential applications, such as all-day thermoelectric power generation and thermal storage-based space heating/cooling. [ABSTRACT FROM AUTHOR]

Radiative cooling of solar cells has been proposed in recent years and has elicited much interest from fields of materials science to engineering science. Herein, a silica micro-grating photonic cooler is proposed, designed, and fabricated to radiatively cool solar cells. It is shown that the micro-grating silica can not only improve the thermal emissivity of the bulk silica to over 0.9 required for enhanced radiative cooling of solar cells but also exhibits a slight anti-reflection effect for sunlight. The outdoor experiment demonstrates that the proposed cooler can passively reduce the temperature of the commercial silicon cell by 3.6 °C when applied on the top of the cell under solar irradiance range from approximately 830 W m−2 to 990 W m−2, even though the cell already possesses a strong thermal emissivity of 0.67 and such a cooler slightly enhance the light trapping effect of the cell. This work provides an alternative way to design the solar-transparent infrared-emissive cooler for enhanced radiative cooling of solar cells and shows its cooling potential. [Display omitted] • A silica micro-grating photonic cooler is proposed to radiatively cool solar cells. • Grating silica exhibits emissivity over 0.9 and simultaneously has anti-reflection effect for sunlight. • A temperature reduction of 3.6 °C is realized for the commercial solar cell with the grating silica. [ABSTRACT FROM AUTHOR]

Solar heating (SH) and radiative cooling (RC) have been regarded as promising clean techniques for thermal energy harvesting and temperature control. However, SH and RC are only a single function of heat collection and dissipation, which means the static device of SH and RC cannot meet the dynamic heat requirement of real-world applications, especially in the daytime. Here, a strategy of dynamic integration of SH and RC is proposed for tunable thermal management. A device (i.e., SH/RC device) that includes a silica cavity, ultrapure single-walled carbon nanotubes (SWCNTs) aqueous dispersion, solar reflective film, and deionized water is designed and fabricated. The outdoor experimental results show that the SH/RC device with SWCNTs media can effectively achieve heat collection with a maximum temperature of 78.9°C, while the SH/RC device with deionized water can achieve heat dissipation. Besides, the temperature modulation ability of the SH/RC device is tested to be 26.3°C and can be theoretically improved to be 60.3°C by improving the solar absorptivity (i.e., 0.9 for SH mode and 0.1 for RC mode) regulation ability of the device and improving its thermal emissivity (i.e., 0.9). Furthermore, annual analysis indicates that the cumulative time in which the SH/RC device temperature is in a comfortable region (i.e., 20°C-26°C) for humans is 60.9% and 30.3% higher than that of the device with individual SH and RC mode. In summary, this work provides alternative thinking for tunable thermal management based on the dynamic utilization of the hot sun and cold universe. • Dynamically integration of solar heating (SH) and radiative cooling (RC) is proposed. • Tunable thermal management can be achieved by SH/RC device. • Temperature modulation ability of SH/RC device is tested to be 26.3 °C and can be improved to 60.3 °C. • Cumulative time that the device is within a comfortable region is enhanced by 30.3%–60.9%. [ABSTRACT FROM AUTHOR]

Radiative cooling coating technology is gaining increasing attention in the context of mitigating urban heat island and tackling global climate change. This paper is concerned with the development of an inorganic geopolymer-based radiative cooling coating using red mud, incorporating varying sizes of TiO 2 and hollow glass beads. The developed colored coating demonstrates its radiative cooling capability in reducing the surface temperature by harnessing the potential of red mud. The physico-chemical properties, surface morphology, and element distribution of the coating were characterized by XRD, FTIR, TG-DAT, SEM and EDS. The coating exhibited lower UV (0.0844) and visible reflectance (0.5275) but high NIR reflectance (0.7536), as well as high infrared emissivity of 0.9455, enabling a red color with a CIE value of L* = 74.56, a* = 9.55, and b* = 11.98, and a maximum temperature reduction of 7.3 °C under the climate of Hong Kong. Additionally, the skid resistance, abrasive resistance and adhesion strength of the proposed coating could meet the requirements of standards, indicating a great potential for footway applications. [ABSTRACT FROM AUTHOR]

Traditional flat PV heat pumps has low irradiation density, large PV area, and the PV evaporators are always fixed, causing large area occupation and lots of irradiation missing, which limit the application and system efficiency. To solve the problems, a novel concentrated PV-air dual-source heat pump system (CPV-DSHP) was proposed in the previous paper, but the annual performance and economic comparison with flat PV-DSHP (FPV-DSHP) are still blank, which are extremely concerning to researchers. Besides, the paper also fills related content about the impact of irradiation composition on the system performance and economics, as well as the irradiation comparison on tracking CPV and fixed FPV surface. From the calculation of the validated model, it's found that the CPV-DSHP system could capture 6098 MJ and 2213 MJ more solar energy, and produce 282.21 kWh and 100.16 kWh more electricity in Garze and Hefei in a year. The annual concentration efficiency is 82.73 % in Garze where direct irradiation accounts for 68.89 %, which is only 73.15 % in Hefei with 39.84 %.The COP PVT is annually lifted by 0.40 in Garze. Although the two systems could both get payback in 5∼6 years, the CPV-DSHP only shows economic advantages in places with good direct irradiation conditions like Garze. • A novel concentrated PV-air dual-source heat pump system (CPV-DSHP) is presented. • The annual performance and economic comparison in different cities are supplemented. • The CPV-DSHP could produce 282.21 kWh more electricity in Garze in a year. • The annual concentration efficiency is 82.73 % in Garze with better direct irradiation. • Payback time is 5∼6 years but CPV-DSHP only shows economic advantage in Garze. [ABSTRACT FROM AUTHOR]

• Three CPC-PV cell modules have been established. • Effect of bus-bar location on electrical performance of CPC-PV cells is indicated. • Effect of bus-bar number on the electrical performance of CPC-PV cells is indicated. • The optimal bus-bar location and number for CPC-PV cells are determined. • The electrical efficiency of the optimized CPC-PV is increased from 11.95% to 13.71%. The compound parabolic concentrator photovoltaic (CPC-PV) cell module is composed of two symmetrical mirrors and a crystalline silicon solar cell. In this study, two new CPC-PV cells based on known CPC-PV cell are established by changing the location and number of bus-bar in crystalline silicon solar cell. The effect of different location and number of bus-bar on the electrical performance of CPC-PV cells was investigated. The numerical simulation of three CPC-PV cells is performed using a two-dimensional finite element model. The electrical performance of three CPC-PV cells are compared, and surface voltage distribution, current density and internal current flow of the crystalline silicon solar cell for each CPC-PV cell are analyzed. The results show that compared with the known CPC-PV cell with bus-bar placed on the right side of the crystalline silicon solar cell, the electrical efficiency of the CPC-PV cell when the bus-bar is placed in middle region of the crystalline silicon solar cell is relatively improved by 14.76%. Finally, it is concluded that the bus-bar optimization based on the non-uniform illumination intensity distribution formed by the concentrator will help to improve the electrical performance of the CPC-PV cell. [ABSTRACT FROM AUTHOR]

Sub-ambient daytime radiative cooling (SA-DRC) has been demonstrated by various advanced emitters in recent studies, which have attracted considerable attention from fundamental sciences and potential applications. Apart from emitter's unique radiative properties, the cooling loss of the emitter affects the performance of SA-DRC in actual applications. Although the emitter is fixed in an enclosure space to decrease the effect of ambient wind on the performance of cooling, the cooling loss of the emitter still exists, and an effective heat transfer coefficient between the emitter and ambient air has directly been widely used to predict the magnitude of the cooling loss power. However, this mathematical description is limited, which will lead to a controversial prediction in some cases. In this study, the cooling loss of the emitter was investigated based on a local environment. The simulation was conducted on the basis of four advanced emitters that were reported in recent studies, and the results show that the cooling loss of the emitter increases with the increasing interface temperature of the enclosure space that surrounds the emitter, which weakens the cooling effect of the emitter. A case study shows that the temperature reduction of an infrared-spectral-selective emitter could be degraded from −3.2 °C to 0.1 °C when the interface temperature increases from ambient temperature to 6 °C higher than ambient temperature, which implies that the cooling effect has been entirely destroyed. [ABSTRACT FROM AUTHOR]

For rooftop building-integrated photovoltaic (BIPV) technology, photovoltaic (PV) modules are typically mounted on the sunny side of a rooftop to receive a high amount of solar irradiance, whereas the opposite side of the rooftop will have free space. This study proposed a novel strategy for building-integrated PV and radiative cooling (RC) system, namely BIPV−RC system, by covering the sunny side of a rooftop with PV modules and its free side with all-day RC modules to integrate solar energy collection and RC utilization into a single building unit. A mathematical model was developed for the proposed BIPV−RC system and a case study was conducted in two tropical cities (Karachi, Pakistan and Riyadh, Saudi Arabia). Results show the total electricity and cooling output of the BIPV−RC system in Riyadh is 462.1 kWh·m−2 and 1315.3 MJ m−2, respectively, approximately 20.7% and 94.0% higher than those in Karachi. Moreover, a comparative study between the BIPV−RC system and the common BIPV and building-integrated RC (BIRC) system was performed and results indicate that the annual total energy output of the BIPV−RC system is nearly 79.1% and 16.8% higher than that of BIPV and BIRC system, respectively. • A novel strategy for BIPV and all-day radiative cooling hybrid system was proposed. • A simulation model of the hybrid system was established and validated. • The feasibility of the proposed strategy was numerically demonstrated. • The radiative cooling mechanism is more suitable for dry regions. [ABSTRACT FROM AUTHOR]

Passive sub-ambient daytime radiative cooling has been demonstrated in previous studies by rigorous spectrum-tailored coolers with high solar reflection and strong thermal emission. In this work, a general strategy to change the relative position between the radiative coolers and the sun was proposed to decrease solar radiation reaching the coolers. In this way, passive sub-ambient daytime radiative cooling was well demonstrated on the basis of two commonly available coolers, coolers A and B. Cooler A was fabricated by attaching a 20 μm-thick polydimethylsiloxane film on a reflective metal substrate, and cooler B was a commercial reflective mirror. A field test was conducted for coolers A and B toward north sky in Hefei (117°E, 32°N), China. Results show that the average temperature drops below ambient temperatures of coolers A and B are 3.2 °C and 7.4 °C, respectively, which indicate that the proposed strategy can achieve passive sub-ambient daytime radiative cooling. Furthermore, the feasibility of the proposed strategy for daytime radiative cooling was also proved using a universal thermal model. This work provides a new insight into passive sub-ambient daytime radiative cooling and opens up a new avenue for common materials to potentially achieve sub-ambient daytime radiative cooling. • A general strategy was proposed to decrease solar radiation reaching the coolers. • The proposed strategy can achieve sub-ambient daytime radiative cooling. • Daytime radiative cooling was demonstrated by commonly available coolers based on proposed strategy. • This work provides a new insight into passive sub-ambient daytime radiative cooling. [ABSTRACT FROM AUTHOR]

Highlights • Miniature dielectric crossed compound parabolic concentrator (dCCPC) as skylights. • The performance of dCCPC skylight panel is compared for fourteen chosen cities. • The polynomial transmittance model of dCCPC is implemented in Grasshopper. • The energy savings in thermal load and lighting of building are investigated. Abstract The potential of miniature dielectric crossed compound parabolic concentrator (dCCPC) panel as skylights for daylighting control has drawn a considerable research attention in the recent years, owing to its feature of variable transmittance according to the sun position, but the viability of using it as skylights in buildings has not been explored yet comprehensively. This paper aims to study the feasibility of utilizing miniature dCCPC panel as skylight in different locations under various climates in terms of energy saving potential besides its daylighting control function. The transmittance of dCCPC panel varies at every moment according to the sky condition and sun position. Due to this specific property, this study novelly implemented a polynomial formula of the dCCPC transmittance in the Grasshopper platform, from which EnergyPlus weather data can be called to calculate the hourly transmittance data of dCCPC skylight panel throughout the whole year. An hourly schedule of transmittance is generated according to the hourly sky condition determined by the daylight simulation through Radiance and Daysim, and is then input to EnergyPlus simulation to predict the energy consumption of a building with dCCPC skylight. Fourteen locations around the world are therefore compared to find the most appropriate place for using miniature dCCPC panel as skylights. The energy saving in cooling, heating and lighting with use of dCCPC skylight panel are investigated and compared with low-E and normal double glazing. The results show that the dCCPC skylight panel can reduce cooling load by mitigating solar heat gain effectively although its performance is affected by several criteria such as sky conditions and local climates. It is generally more suitable for the locations with longer hot seasons, e.g., Log Angeles, Miami, Bangkok and Manila, in which dCCPC could provide up to 13% reduction in annual energy consumption of building. For the locations having temperate and continental climates like Beijing, Rome, Istanbul and Hong Kong, a small annual energy saving from 1% to 5% could be obtained by using dCCPC skylight panel. [ABSTRACT FROM AUTHOR]

A novel photovoltaic/radiative cooling (PV/RC) hybrid system based on a selective plate is proposed. This system can generate electricity via diurnal PV conversion and obtain cooling energy by radiative cooling. We introduce a comprehensive photonic approach to simultaneously reduce impractical solar radiation absorption of the selective plate and enhance its thermal radiation for the hybrid system. Initially, we design a photonic structure made of 1D multilayer stack and 2D photonic crystal, which can selectively reflect solar radiation and actively radiate heat to the outer space while maintaining its solar transmission in PV conversion band (0.3–1.1 µm). Then, we demonstrate that applying the photonic structure to a monocrystalline silicon solar cell can obtain a diurnal electricity output of 99.2 W m −2 and generate a nocturnal RC power by 128.5 W m −2 , indicating 6.9% and 30.5% higher than those of a bare cell. In addition, the potential cooling energy obtained is far more in this structure than in existing RC emitters, including daytime RC emitter reported in a recent research. Results indicate that a comprehensive photonic approach can be used to design spectral selective structures for advancing the applications of exploiting solar energy harvesting and radiative cooling utilization. [ABSTRACT FROM AUTHOR]

Parasitic solar heating of the radiative cooler remarkably counteracts the cooling effect generated by radiative cooling. Many previous works have contributed to improving the solar reflectivity of the cooler to reduce its solar absorption, including using highly reflective film or optimized scattering effect. Herein, an easy and passive sunlight blocking strategy based on geometrical optics is applied to reduce the solar heating power of the cooler by using a ring-like shield to prevent the propagation of direct sunlight, corresponding to decoupling the cooler from solar beam irradiance. A black paint-coated cooler with strong solar absorption of over 0.9 and a porous polytetrafluoroethylene (P-PTFE) cooler with a high solar reflection of over 0.9 are fabricated to demonstrate the feasibility of the sunlight blocking strategy. Results show that radiative cooling to 3.5°C and 6.5°C below ambient temperature under average solar irradiance of 500 W m−2 is achieved by the black paint and P-PTFE, revealing that the proposed sunlight blocking strategy contributes to efficient sub-ambient daytime radiative cooling. Theoretical analysis not only proves the effectiveness of the sunlight blocking strategy but also reveals that cooler with selective emission within the atmospheric window is more sensitive to sunlight, as well as capturing the radiative cooling performance under different conditions. • A passive sunlight blocking strategy is proposed for daytime radiative cooling. • Sub-ambient radiative cooling effect is achieved by black paint under sunshine. • Radiative cooling performance of the selective cooler is more sensitive to sunlight. • This work provides a new pathway for sub-ambient daytime radiative cooling. [ABSTRACT FROM AUTHOR]

Transparent envelopes account for a large amount of energy consumption of buildings, especially in hot climate regions. Glass is one of the main materials in transparent envelopes, so modifying the radiative properties of the glass is an alternative way for building energy saving. Here, a semi-transparent radiative cooling (ST/RC) glass was proposed by integrating the selective utilization of solar energy and passive radiative cooling. Comparative experiments based on two small-scale boxes were performed, which shows that the indoor air temperature of the box with the ST/RC glass is lower than that with the ordinary glass and the maximum temperature difference reached 16.4 °C, indicating that ST/RC glass can reduce the waste heat generated in the indoor environment. Besides, the daylighting level with the ST/RC glass is decreased by approximately 2/3 to support comfortable daylighting. Moreover, large-scale modeling of the building located in the Maldives was conducted and results show that the energy consumption of building could be saved by 21%–66.5% when the glass is modified to transmit visible light, reflect other solar irradiance, and emit like a blackbody, which indicates that the strategy of using light and thermal management of glass has the potential to reduce the energy consumption of buildings. • A strategy of light and thermal management of the glass for building energy saving is proposed. • A semi-transparent radiative cooling (ST/RC) glass is proposed and fabricated. • The temperature of the indoor air with ST/RC glass can be reduced by over 16 °C. • The electricity saving ranges from 21% to 65 % under the light and thermal management strategy of the glass. [ABSTRACT FROM AUTHOR]

Photovoltaic-thermoelectric (PV-TE) conversion is a promising method for power generation, which converts solar power into electricity using the photovoltaic (PV) effect of solar cells and simultaneously generates electricity by the Seebeck effect of the thermoelectric (TE) device based on the waste heat of solar cells. Here, the power generation of the PV-TE device at night is experimentally demonstrated using radiative cooling that harnesses the cold of the universe directly. The PV-TE device is constructed by attaching a TE device on the bottom of the glass-covered PV module, with a heat sink stuck on the opposite side of the TE device. The open-circuit voltage of the TE device integrated into the PV-TE device was measured to be approximately 9 mV, indicating that the PV-TE device can definitely generate electricity from the darkness. Moreover, a new configuration of the PV-TE device for continuous power generation in the day and night is conceptually proposed for further consideration. In summary, this work proves the possibility of the PV-TE device for nighttime power generation, which could provide an alternative pathway for a wide range of nighttime and all-day power-consumed applications, such as lower power sensors and monitors. • Nighttime power generation of the PV-TE device was experimentally demonstrated. • An average output voltage of the PV-TE device was measured as 9 mV in night. • A new configuration of the PV-TE device for continuous power generation is proposed. • This work provides an alternative pathway for nighttime and all-day applications. [ABSTRACT FROM AUTHOR]

• The principle of spectrally selective approaches for cooling solar cells is analyzed. • Radiative cooling is a significant method for solar cells to dissipate waste heat. • Full-spectrum thermal management of solar cells is a novel way to cool solar cells passively. • The cooling effect of full-spectrum thermal management is better than radiative cooling. • Appropriate material is the biggest challenge for this new cooling technology. Waste heat is generated in solar cells during the daytime because they operate with a limited electrical efficiency. Moreover, the generated heat increases the solar cells' operating temperature, and this has an adverse effect on their electrical efficiency. Therefore, numerous cooling methods have been developed to cool solar cells, such as forced air/water flow, hybrid photovoltaic/thermal system, and phase change material based photovoltaic application. Recently, a novel concept of changing the solar cells' spectral response to both sunlight and thermal radiation has been proposed and developed to provide a passive cooling method for solar cells, which has drawn much attention from materials science to engineering fields. In this paper, the recent advancements of such a spectrally selective approach to passively cool solar cells, including radiative cooling of solar cells and full-spectrum thermal management of solar cells are reviewed, analyzed, and discussed from fundamental principles to detailed demonstration. Furthermore, the technical challenges involved in developing this new cooling technology are discussed. This paper is devoted to give a systematic introduction to a new passive cooling technology for solar cells by controlling the spectral property of solar cells, aiming to open a new opportunity for solar cells' cooling. [ABSTRACT FROM AUTHOR]

• The feasibility of hybrid utilization of photovoltaic and radiative cooling was demonstrated. • Outdoor experiment and simulation study was conducted for performance evaluation. • Daily average electrical efficiency was measured as 14.9% on a mostly sunny day. • The net cooling power was evaluated as 72.9 W·m−2 on a mostly clear night sky. The concept of hybrid utilization of daytime photovoltaic (PV) conversion and nighttime radiative cooling (RC), namely, PV–RC, was proposed and experimentally demonstrated. A PV–RC hybrid module with a size of 1380 mm × 720 mm was manufactured and characterized, and a corresponding PV–RC hybrid system was established. The PV–RC hybrid system can generate electricity at daytime by PV conversion and simultaneously obtain cooling energy by nighttime RC. PV performance of the hybrid system was tested on a mostly sunny day, and measured results showed that the daily average electricity output and electrical efficiency were 94.0 W·m−2 and 14.9%, respectively. Besides, nighttime RC performance of the hybrid system was measured on a mostly clear night sky and net cooling power of the PV–RC system was evaluated as 72.94 W·m−2 when temperature of the PV-RC panel was equal to ambient air temperature. Furthermore, a validated thermal analysis model was used for parametric study and results show that nighttime RC performance will be enhanced by dry atmosphere and low parasitic cooling loss. In summary, this work presented an experimental and simulation study for PV–RC hybrid system, which acts as a demonstration project of a real system. This study is a new attempt towards a real-world application of comprehensive utilization of solar energy and RC, which provides a good choice for cooling demand dominated buildings. [ABSTRACT FROM AUTHOR]