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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 linear relation between the efficiency of solar ponds and factor θ d H which is the temperature difference between the pond bottom and the ambient divided by the average insolation is presented. This relation, which has been developed based on a steady state analysis provides valuable information on the relative importance of the parameters involved in the operation of solar ponds. It is found that the existence and the thickness of the top convective zone has a profound negative effect on the yield of solar ponds. The optimum thickness of the density gradient layer under various conditions is also presented. The effect of ground losses is discussed, and it is shown that for the case of wet soil, especially if the level of the underground water is high, the pond should be thermally insulated. It is also shown that the steady state analysis can predict with good accuracy the yearly average response of solar ponds under transient conditions.

The salt gradient solar pond is a long-term heat storage system with a considerable warm-up time. A pond is efficient when it reaches the desired temperature quickly and maximum heat is subsequently retrieved at steady state. This requires optimum sizing of the non-convective zone. In the present work, the optimum size of the non-convective zone for fast warm-up is determined. This is found to differ considerably from the optimum size of the steady state criterion. The possibility of achieving both performance parameters, i.e. fast warm-up and maximum heat collection later on, is analyzed. It is suggested that when commissioning a pond, the size of the non-convective zone should at first be the optimum value from the warm-up rate criterion, but may later be changed to the optimum size from the steady state criterion.

Abstract Finding diverse applications of installed PV based power generating unit is necessary for optimal utilization of energy produced by these units over a period of time. This paper proposes a high gain boost converter that can be used as a DC source for electric vehicle charging application in existing PV based solar pump set-up. The proposed DC-DC converter uses two-stage boosting to achieve a high voltage gain in the form of quadratic quadrupled boost factor. Low turns ratio in coupled inductor reduces the loss components of magnetic part largely. Another advantage of the proposed converter is its operation at lower duty ratio (~0.5) to achieve the desired voltage gain for photovoltaic application. Further, leakage inductance is effectively utilized to achieve ZCS of solid-state devices in conjunction with magnetizing inductance, which provides ZVS for the efficient operation of converter. To analyze the performance of proposed converter for electric vehicle charging application, simulations were carried out using PSIM/MATLAB software and results were validated using experiments conducted on a 250 W hardware prototype developed in the laboratory. A boost factor of 7.8 is achieved at a turn’s ratio of 1.9 for ~35% duty ratio of main switch. The maximum efficiency of ~93% is measured for designed converter.

Abstract This article outlines the minimum set of concepts of hydrological optics required for an understanding of solar energy penetration into bodies of water. The practical application of these concepts to solar ponds, especially by means of the Monte Carlo modeling procedure, is discussed, and an account is given of the optical measurements that need to be made in order to arrive at an understanding of radiation transfer within any given solar pond. The results are presented of a series of Monte Carlo calculations of the behavior of solar radiation within idealized but realistic solar ponds with optical properties covering a wide range of values. The effect on energy collection efficiency of varying the concentration of colored substances, the scattering coefficient, and the albedo of the bottom are explored in detail. The optical criteria that must be satisfied for successful solar pond operation are briefly discussed.

Abstract To operate centrifugal pump against higher discharge pressure and to achieve specific speed for delivering the water, the level of irradiance required is quite high. Therefore, by knowing the operating pressure this problem may be minimized by using energy storage devices like battery or supercapacitor operated in parallel with the SPV module. Here is the need to select a proper configuration of solar PV water pumping system (SPVWPS) using energy storage devices for the economic application. Therefore, a new approach is made towards studying different configurations of 7SPVWPS with battery and supercapacitors under varying discharge pressure and evaluate the performance parameters. Four different configurations of SPVWPS using centrifugal pump are considered, namely, directly coupled, with battery, with the supercapacitors and with a battery-supercapacitor hybrid, to determine the optimum configuration for higher system performance. The experiment have been carried out on a small scale SPVWPS with 2 m and 3 m dynamic head of the pump on sunny days at Haldia, India. The comparison of the performance for the different configurations have been reported. The study reveals that the supercapacitor based configuration give highest instantaneous efficiency. The centrifugal pump powered by SPVWPS using battery delivers a maximum of 2964 L per day for 2 m dynamic head whereas for 3 m dynamic head SPVWPS using supercapacitor delivers a maximum of 1826 L per day. An economic comparison is also done for the different topologies.