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It has been found that the values of ratio of hourly global illuminance to daily global illuminance, rvt, are very close to the corresponding values for global solar radiation, rt, examined from the measured data of six IDMP [1] (International Day light Measurement Programme) locations. This has been further confirmed by examining the values for rvt and rt as calculated from TMY2 [2] (Typical Metrological Year) data base for primary locations. Based on this, it has been proposed that the correlations available in literature to predict rt can be employed to predict rvt. Adequacy of the correlation due to Collares-Pereira and Rabl [3] available for rt has been examined to predict rvt as obtained from TMY2 data base for the 56 primary locations. It has been found that the values of rvt obtained from measured illuminance data of six locations have been predicted within a rms difference of 2.71% and within a rms difference of 4.3% for the 56 primary locations of TMY2 data when the correlation due to Collares-Pereira and Rabl for rt has been employed.

Abstract In building integrated photovoltaic (BIPV) systems, PV elements are integrated along with the building which often serves as the exterior weathering skin. PV researchers from various countries have been working for several years to optimize these systems. Sustainable BIPV system has many benefits such as the building itself becomes the PV support structure, and the BIPV components displace the conventional building materials and labor cost, thereby reducing the net installed cost of the PV system and building construction. It also provides on-site generation of electricity and architectural elegance, which increases the market acceptance of the buildings. The BIPV systems can be interfaced with the available utility grid or used as off-grid systems. This paper identifies sustainable building concept in South Asian countries and role of BIPV applications in sustainable building. This article gives review of BIPV applications in South Asian countries. Finally, Barrier and challenges of BIPV system have been discussed and future direction is highlighted.

Abstract This paper presents one of the first discussions on the new Solar Atlas of Saudi Arabia, which was launched in February 2014. It assesses selected solar resource and surface meteorological measurements available from the new Renewable Resource Atlas for Saudi Arabia developed by the King Abdullah City for Atomic and Renewable Energy (KACARE) as part of the Renewable Resource Monitoring and Mapping (RRMM) Program. The Solar Atlas provides live data recorded from 41 stations across the country. Accurate solar resource data is critical in reducing technical and financial risks of deploying utility-scale solar energy conversion systems. This paper presents solar maps of the country over time, showing that the direct normal irradiance (DNI) in various regions of the country ranges from approximately 9000 W h/m 2 /day in the summer months to 5000 W h/m 2 /day in the winter months. Global horizontal irradiance (GHI) in various regions can be as high as 8.3 kW h/m 2 /day. One year of ground based solar radiation measurements from new stations at KACARE Headquarters Riyadh and Qassim University are compared with satellite-based model estimates of long-term DNI and GHI solar resources on a monthly mean daily total basis. Comparing the locally measured DNI data at KACARE Headquarters Riyadh with GeoModel, the average difference is about 6.9% of the reported values, the average measurement uncertainty being 8.4%. For GHI measured at KACARE Headquarters Riyadh, a fairly good agreement can be seen between the RRMM values and GeoModel with the average difference being about 5.6%, while the average measurement uncertainty being 6.7%. It might be noted that the GeoModel has data uncertainties for monthly mean daily total radiation in the range of ±8% to ±15% for DNI, and ±4% to ±8% for GHI. Finally, the paper reviews data from the recording station at Qassim University (QU), which is equipped with a variety of instruments for measuring solar radiation and surface metrological conditions. The measured values of DNI at QU varied from a maximum of 8367 W h/m 2 /day in July to a minimum of 4702 W h/m 2 /day in January. In terms of percentages, the average difference between the measured monthly mean daily total radiation and the GeoModel estimates is about 5.4% of the reported values, the average measurement uncertainty being 5.1%. In most cases, the observed differences between measured and modeled data were within the combined estimated uncertainty. The results from Solar Atlas are critical in guiding policies, reducing the risks for deploying solar facilities and providing judicious information for construction of solar facilities.

Abstract Hybrid photovoltaic thermal systems consisting of solar panels and solar thermal absorbers are generally used for improving the electrical and thermal efficiency of the photovoltaic panel by cooling. Thus, thermal energy produced can be used for other applications. Depending on solar insolation and location, building integrated photovoltaic (BIPV) systems are designed and developed to fulfill energy needs. This paper reviews the detailed study on the effect of the front surface, back surface and combined front and back surface cooling on the water-based photovoltaic systems. This paper also discusses different designs of solar thermal absorber collectors. The front surface cooling resolves two problems. Firstly, it significantly reduces the PV panel temperature by 22–27 °C depending on the cooling phenomena used and secondly, it cleans the PV panel, thereby increasing the optical efficiency. The PV panel temperature reduction (5–6 °C) in the water spraying cooling system is more than water flowing over the front surface. The photovoltaic thermal absorber collector system is the most economically viable system from the electrical and thermal energy generation perspectives. The evaporative cooling on the backside of PV panels using clay and cotton wick structure could be an effective solution for a standalone PV system. It is observed that dual cooling is suitable for PV panels cooling in a hot arid region but needs further investigation. Finally, the environmental impact and economic feasibility of water-based photovoltaic cooling systems are discussed.

Abstract Buildings often have fixed function spaces that are complimentary or incompatible with thermal comfort (18–28 °C). Synergetic relationships ameliorates energy shortage and affords comfort. Galvanized iron roof two-storey houses of North-East India were studied to develop a theory-and-strategy to optimize design process and energy conservation. Methods include affordance theory criticism, surveys, simulations, synergy analysis. Parametric strategy on passive design affordances examines human comfort and temperature on diurnal time scales: Daytime (08–17 h), Evening (17–22 h), Night (22–08 h) in various seasons. Under flexible ventilation, living-dining space (S1) shows optimum temperature ranges: 20–28 °C in autumn (M1), 17–22 °C in winter (M2), and 20–31 °C in summer (M3) due to the complementary combination of passive design elements and can function as bedroom, living-room, kitchen, and social space in most seasons. In the attic-space flexible ventilation shows peak temperatures of 42 °C (autumn) and 48 °C (summer) due to low thermal mass but high thermal conductivity envelopes, and low air-changes rate (0.5 ACR) above 28 °C. Normal ventilations with 30 ACR in autumn, and a combination of 30 ACR (night) and 0.5 ACR (day) in summer reduced maximum temperature to ≤35 °C in autumn, and ≤41 °C in summer. Attic-space (S2) shows ≤29 °C in winter daytime and ≥20 °C in summer nights due to the envelope’s high heat emissivity (0.8) and function as day space in winter and summer bedroom. Shaded veranda (S3) shows low temperature (18–28 °C) in summer evening and afternoon and can function as shaded space for light work and enjoying fresh air. Passive design connotes responsiveness of spaces to the climate, and affordance theory’s complementarity lifestyle adds novelty, and it is critical to energy and space efficiency. Climate analysis affords perceptions of space and climate relationship. Parametric strategy straddles differences between space, climate, and functions to ameliorate energy needs and optimize design process.

Abstract With an aim to prepare phase change material (PCM) as self-sustaining film from poly(ethylene glycol) (PEG) having reduced hydrophilicity, cross-linking of PEG and hydroxy-terminated poly(dimethyl siloxane) (HTPDMS) was done by using tetraethyl orthosilicate (TEOS) as a cross-linking agent. Following the confirmation of the crosslinked polymer using FTIR and 13C-solid state NMR, the crystallization properties were studied using X-ray diffraction and polarized optical microscopy. DSC analysis indicated an increase in enthalpy with increasing concentration of PEG. The enthalpy of fusion and crystallization was observed to reach a maximum of 125 and 104 J g−1 respectively. Contact angle of 89.5° has been achieved for polymer with highest concentration of HTPDMS. The material with lowest PEG concentration was film forming in nature. This material can be extensively used as a thermal energy storage material particularly, in smart packaging.

Abstract Geostationary satellites offer the possibility of producing high-frequency time series irradiance datasets, covering a large geographical area. Here, we derive half-hourly global irradiance (GHI) at 4 km spatial resolution from visible channel radiance of INSAT-3D satellite using a semi-empirical model and validate it against 19 ground stations over 2015–16, across India. Our model uses the Advanced Solis clear-sky model with monthly climatological values of modern-era retrospective analysis for research and applications-2 (MERRA-2) aerosol optical depth (AOD) and precipitable water (PW) as inputs. The relative root mean squared error (rRMSE) and relative mean bias error (rMBE) are 24.02% and −0.05%, respectively. Over the validation period, INSAT-3D derived GHI outperformed SARAH-E model and MERRA-2 reanalysis GHI.

In north china, agriculture products may be harvested above safe storage moistures to prevent excessive field losses. A solar-assisted heat pump drying system (SAHP) with an energy storage tank has been proposed to meet the demand in this field. The drying system is designed in such a way that some of the components can be isolated depending on the weather conditions and usage pattern. The performance of the whole system has been modeled and investigated under a typical summer day of the city Baoding, China. Results show that the coefficient of performance (COP) of the SAHP drying system is 5.369, while it is 3.411 without solar energy inputs. With an energy storage tank, the SAHP drying system performs more stable and modulates the mismatch between solar radiation and the energy needed in the night. Other discussions on collector numbers, drying time and drying temperature are also processed, which will be helpful to apply the system in China.

This paper presents the hourly mean solar radiation and standard deviation as inputs to simulate the solar radiation over a year. Monte Carlo simulation (MCS) technique is applied and MATLAB program is developed for reliability analysis of small isolated power system using solar photovoltaic (SPV). This paper is distributed in two parts. Firstly various solar radiation prediction methods along with hourly mean solar radiation (HMSR) method are compared. The comparison is carried on the basis of predicted electrical power generation with actual power generated by SPV system. Estimation of solar photovoltaic power using HMSR method is close to the actual power generated by SPV system. The deviation in monsoon months is due to the cloud cover. In later part of the paper various reliability indices are obtained by HMSR method using MCS technique. Load model used is IEEE-RTS. Reliability indices, additional load hours (ALH) and additional power (AP) reduces exponentially with increase in load indicates that a SPV source will offset maximum fuel when all of its generated energy is utilized. Fuel saving calculation is also investigated. Case studies are presented for Sagardeep Island in West Bengal state of India.