• Energy Research
• 12. Responsible consumption close
• IN close
• CN close
• AU close
• Solar Energy close

Abstract There are instances in remote areas where heat is being wasted, e.g., in internal combustion, engines, etc. Some of this heat can be recovered to produce distilled water in solar stills. The solar still replaces the cooling tower, ponds, or radiators normally used to control the engine temperature. The diesel cooling water in such a system remains separate from the saline water in the solar still. The advantages of using such a system compared with a conventional solar still are: 1. (a) water costs are very much reduced 2. (b) the area occupied is much less, i.e., about 1 5 th 3. (c) production has much less seasonal variation 4. (d) the efficiency of the solar still is improved due to the higher operating temperatures. From experiments conducted at Highett using a Mk VI solar still fitted with a simple heat exchanger and a separate electrically-heated source of hot water to simulate the waste heat, design data are not available for application to working systems. The information required to match a solar still to a diesel's cooling requirement is: 1. (a) engine efficiency 2. (b) hourly fuel consumption 3. (c) hourly solar radiation 4. (d) hourly ambient temperatures. A by-product of this work has been the production of a “solar water heater” which costs less than that of the cheapest conventional system. This “solar” hot water system uses a heat exchanger similar to what is used to transfer the waste heat to the saline water. It is envisaged to have hot water productions approximately the same as the distilled water productions. The influence of hot water production on the output of the waste heat solar still is discussed.

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 The power conversion efficiency of the photoelectrochemical cell AuRhodamine BAu was found to be (2.4 ± 0.2) × 10 −6 per cent under typical operating conditions. A ten-fold improvement could be expected from constructional modifications, but further increases in efficiency would require changes in the cell chemistry. The low power conversion efficiency can be related to a low (4.7 × 10 −2 per cent) efficiency for the production of the open circuit photovoltage; a low (2.2 × 10 −2 per cent) quantum efficiency for the production of the short circuit current; and to markedly non-rectangular voltage-current characteristics. The deviations from a rectangular relationship and the low efficiency of current production arise from mass-transport limitations rather than from ohmic losses or activation polarisation. The low voltage efficiency probably arises from inefficiencies in the photochemical and electron transfer steps which lead to photovoltage production. The limitations of this type of cell as a solar energy conversion device are discussed.

Abstract Disposal of waste plastics imposes serious problems to the environmentalists, since plastics are non-biodegradable and emit carcinogenic gases when incinerated. In a country like India, where solar energy is abundantly available, semiconductor photo catalysis may be a clean and economic technology to combat such a problem. In the present work we addressed to the problem of degrading polyvinyl chloride (PVC) by photo catalysis by exposing a PVC–ZnO composite film to solar radiation as well as to artificial UV radiation in presence of water and air. Degradation in the two processes has been compared. The surface morphology as well as the FTIR spectroscopy of the irradiated film has been critically examined. The degradation was measured by weight loss data and was found to follow a pseudo-first order rate equation. The various parameters studied were loading of the semiconductor and intensity of UV radiation. A possible mechanism has been suggested and the corresponding rate equation has been modeled. The model has been validated by the experimental data.

Abstract A comprehensive prediction for molecular power conversion efficiency and designing novel sensitizers are effective strategies for preparing highly efficient dye-sensitized solar cell devices. In this work, four high-efficiency D-π-A type triazatruxene (TAT) based organic dyes have been designed by changing spacers and anchoring groups of the reference molecule. A global evaluating model that illustrates the micro-mechanism of enhanced molecular photoelectric performances through importing graphene quantum dots (GQDs) was built. Upon incorporating GQDs, an obvious absorption peak with high molar extinction coefficients appeared around the ultraviolet region. Furthermore, molecular light-harvesting efficiency (LHE) in the visible region has increased, and molecular charge transfer performance enhanced, and molecular regeneration ability improved, which contributed to the improved photocurrent (Jsc) and power conversion efficiency (PCE). Molecular ZL003 through the global evaluating model showed (Jsc = 19.03 mA cm−2, Voc = 0.874 V, PCE = 14.5%) are in accordance with the experimental data (Jsc = 19.74 mA cm−2, Voc = 0.957 V, PCE = 13.4%). The model can provide a basis for evaluating molecular photoelectric performance. The micro-mechanism that the GQDs enhance molecular photoelectric performances has been revealed in the framework of GQDs photo current-voltage evaluating model.

Abstract Quantum Dot Sensitized Solar Cells are considered as the potential third generation solar cells due to their suitable optoelectronic properties for photovoltaic response. The possibility of size and composition tunability makes quantum dots as relevant absorber materials to match the wider solar spectrum more efficiently. In conjunction, the possibility of multiple electron-hole pair generations at the cost of single photon i.e. multiple carrier generation is showing potential to overcome the theoretical single junction power conversion efficiency limitations. Quantum dot sensitized solar cells are showing power conversion efficiencies up to 12%, very close to its counterpart dye sensitized solar cells. However, QDSSCs efficiencies are still lagging behind the conventional solid state single junction solar cells. In this review, we will discuss the initial evolution of quantum dot sensitized solar cells with their microscopic working principles. The review will also address development of key building blocks and factors such as various interfaces in QDSSCs, carrier transport and recombination across different interfaces, affecting the power conversion efficiency. Further, fundamental concepts of carrier multiplication and possible theoretical models for multiple exciton generation are discussed towards their impact on the power conversion efficiencies of quantum dot sensitized solar cells.

Abstract Multiple fuel use, incorporated within the concept of fuel stacking is prevalent in households at the beginning and mid-way in their ascension up the energy ladder. However, households cannot fully let go of their traditional energy sources presenting inherent policy complexities and contradictions within energy transition theories. Empirical insights into the determinants of clean energy transitions are presented that highlight the need to recognise both fuel switching and stacking occurs in many rural households. It focuses on rural communities in India and illuminates policy dilemmas. The study reveals that fuel stacking is likely to remain a key part of the socio-cultural energy tradition that will impact progress towards low carbon and a cleaner energy transition. We therefore argue targeted policy interventions, multi-stakeholder collaboration and strong energy governance is needed to incorporate socio-cultural traditions particularly linked to cooking. This suggests new energy policy that must offer flexibility in order to achieve the twin goals of universal energy access and decarbonising energy systems.

Abstract The results of past and ongoing activities, in successive IEA SHC (solar heating and cooling) Tasks, suggest enormous potential for solar cooling technologies to reduce greenhouse gas emissions. However, solar thermal cooling still faces barriers to emerge as an economically competitive solution. IEA SHC Task 48 was introduced to gather learnings from existing installations, and to find technological and market solutions, which could enable industry to deliver solar thermal driven heating and cooling systems that are efficient, reliable and cost competitive. The selected experiences of these research activities were clustered into 10 qualitative key principles for successful design and operation of SHC systems. Three existing systems are fully discussed in a solar cooling design guide (Mugnier et al., 2017). This paper aims to introduce these key principles in its general format. The background to the qualitative statements is explained, supplemented with examples from the context of Task 48 and compared with recent literature. Furthermore, a survey was conducted among SHC experts, who provide an assessment of the importance of the principles. The result shows that all principles have their eligibility. However, it turns out that there are three main categories of principles: (i) essential, (ii) important and (iii) controversial. Following the key principles is not a guarantee, but they can support researchers, designers and contractors to implement solar heating and cooling systems successfully.

In this study, two solar slurry photocatalytic reactors i.e., batch reactor (BR) and batch recycle reactor with continuous supply of inert gas (BRRwCG) were developed for comparing their performance. The performance of the photocatalytic reactors were evaluated based on the generation of hydrogen (H{sub 2}) from water containing sodium sulfide (Na{sub 2}S) and sodium sulfite (Na{sub 2}SO{sub 3}) ions. The photoreactor of capacity 300 mL was developed with UV-vis transparent walls. The catalytic powders ((CdS/ZnS)/Ag{sub 2}S + (RuO{sub 2}/TiO{sub 2})) were kept suspended by means of magnetic stirrer in the BR and gas bubbling and recycling of the suspension in the BRRwCG. The rate constant was found to be 120.86 (einstein{sup -1}) for the BRRwCG whereas, for the BR it was found to be only 10.92 (einstein{sup -1}). The higher rate constant was due to the fast desorption of products and suppression of e{sup -}/h{sup +} recombination. (author)