Applied Mechanics and Materials Vols. 592-594

Abstract: Due to the electrical load mismatch some amount of non-conventional energy may be exported to the grid because the electrical demand is temporarily lower than production, whereas a consumption, which is higher than production and/or that does not match the available conventional generation, will require to be supplemented by the public grid electricity. At present, the gap between demand and supply is very high. A continuous supply in constrained power system through contingency planning for unique needs becomes a must. Government and private sectors’ combined participation in bridging the gap between demand and supply by setting up their captive power plants has to ensure regular and economic power supply. The main objective of this study is to analyse the technical and non technical problems being faced in power shortage. Normal 0 false false false EN-IN X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:8.0pt; mso-para-margin-left:0cm; line-height:107%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-fareast-language:EN-US;}

Abstract: A single basin single slope solar still with 0.82mx 0.81m x 0.75m has been fabricated with G.I sheet and tested with different water depths of 2,3,4cm. Various solid and liquid sensible heat storage materials, Evaporative surface materials are used in the form of billets, in the still. To reduce glass cover temperature the outer glass was cooled by using sprinkler manually at regular interval of time. Theoretical analysis was performed and compared with experimental values. The performances of modified still were compared with conventional still of same size running under the same meteorological conditions. The solid sensible heat storage materials produces48% more productivity than conventional still. Liquid sensible heat storage material produces 19% more than conventional in till. The payback period of the still was 340 days.

Abstract: Fossil fuels reserves are decreasing in a rapid pace due to more power consumption. Advancement of technology, usage of electrical equipments and increase in population are the main reasons for energy consumption. In order to meet the energy demand and to sustain the environment depending on non-conventional sources of energy is inevitable. Solar energy is the clean energy source which is naturally available in abundant and does not contribute to green house gases. The energy from the sun is directly converted into the electricity by using photovoltaic (PV) cells without using any intermediate steps. Solar charge controller is connected to the PV system for regulating the voltage and current coming from PV panel and to prevent overcharging of battery thereby increasing the life of battery. PID controller is used to obtain the desired voltage and for constant recharging of lead-acid battery. This paper addresses the modeling and simulation of Photovoltaic system under Maximum power Point Tracking (MPPT) condition and design of Buck converter with PID controller for constant charging of battery.

Abstract: Water is one of the most significant substances on earth. With growing population and exploitation of resources, the quality and availability of water is deflating. Many conventional methods like reverse osmosis, electrolysis and in situ chemical oxidation are being used for water purification. Solar distillation, a simple and economical method using renewable solar energy is being considered in various parts of the world. Research is carried out in various parts of the world to improve the efficiency of this process. In this paper an attempt is made to model the performance of a solar still and is used to analyse the performance of an improved solar still which has an additional compartment placed above the conventional solar still in order to increase its yield for the same area. The water held in the top compartment is heated with the help of solar radiation and hot water is supplied into the bottom compartment of the solar still through a flat plate collector of 1 m². The model indicates that with an inclusion of top compartment, the yield of the modified duplex solar still increases by 128 %. The effective area of the solar still is 1 m². The angle of inclination of the glass cover is taken as 19^o and the thickness of the glass cover for the top and bottom still is considered as 3 mm and 6 mm respectively. The payback period and the cost per litre of potable water produced with modified solar still is calculated and is compared with the conventional solar still.

Abstract: Efforts for harnessing solar energy were made many decades ago. Solar cooking was opted worldwide as a convenient and economical method to cook food. Since then, several investigators have studied various aspects of solar cooking. The studies on solar cookers can be broadly classified into the following categories: (a) design, fabrication and testing of new types of solar cookers, (b) methods of boosting the solar energy on the cooker aperture using booster mirrors,(c) energy storage types of cookers, for use indoors and also during off sunshine periods, (d) tests on different types of cooking vessels and (e) modeling and simulation techniques.

Abstract: In this paper, an optical analysis of parabolic trough collector with flat concentrating photovoltaic receiver is carried out by utilizing non-uniform intensity distribution model of the solar disk. The optical system simulation tool ASAP is used to analyze the parabolic trough system with single axis tracking having a mirror aperture of 1m and length of 3m. The impact of random errors including slope error, apparent change in sun’s width, tracking errors on the optical performance of trough system is carried out. The errors are assumed to follow Gaussian (normal) distribution and analyzed statistically. It is found that intercept factor increases with rim angle for given total error of 5, 10 and 20 mrad. Geometrical concentration ratio is varied to see the effect on the intercept factor and compared for various error values. The numerical results show that for De-focused performance (L=0.1f) the local concentration ratio value is 23 for the 45° rim angle. Numerical results are compared with the analytical data available in the literature which show good agreement.

Abstract: Solar energy collectors are a special kind of heat exchangers that transform solar radiation energy to internal energy of the transport medium. The major component of any solar system is the solar collector. This is a device which absorbs the incoming solar radiation, converts it into heat, and transfers this heat to a fluid (usually air, water, or oil) flowing through the collector. The measurement of the flat plate collector performance is the collector efficiency. The collector efficiency is the ratio of the useful energy gain to the incident solar energy over a particular period of time. The useful energy gain is strongly depends on the collector efficiency factor and this factor directly influenced by few parameters i.e. the centre to centre distance of absorber tubes W , thickness of absorber plate δ and heat loss coefficient U_L. This paper has been focused on the relation between W with collector efficiency factor of serpentine tube solar flat-plate collector. This study shows that if we increase the W then Fˈ decreases.

Abstract: In recent years with the exacerbation of energy shortage, water crisis increases around the world. With the continuous increase in the level of greenhouse gas emissions, the use of various sources of renewable energy is increasingly becoming important for sustainable development. Due to the rising oil price and environmental regulations, the demand of utilizing alternative power sources increased dramatically. Alternative energy and its applications have been heavily studied for the last decade. Energy and water are essential for mankind that influences the socioeconomic development of any nation. Pure water resources become more and more scarce every day as rivers, lakes wells and even seawater pollution rapidly increases. Solar energy is one promising solution to secure power and potable water to future generation. The process of distillation can be used to obtain fresh water from salty, brackish or contaminated water. Water is available in different forms such as sea water, underground water, surface water and atmospheric water. Clean water is essential for good health. The search for sustainable energy resources has emerged as one of the most significant and universal concerns in the 21^st century. Solar energy conversion offers a cost effective alternative to our traditional usages. Solar energy is a promising candidate in many applications. Among the alternative energy sources used for electricity production, wind and solar energy systems have become more attractive in recent years. For areas where electricity was not available, stand alone wind and solar systems have been increasingly used. The shortage of drinking water in many countries throughout the world is a serious problem. Humankind has depended for ages on river, sea water and underground water reservoirs for its fresh water needs. But these sources do not always prove to be useful due to the presence of excessive salinity in the water. To resolve this crisis, different methods of solar desalination have been used in many countries. Distillation is a well known thermal process for water purification, most importantly, water desalination. Most of the conventional water distillation processes are highly energy consuming and require fossil fuels as well as electric power for their operation. Single basin solar still is a popular solar device used for converting available brackish or waste water into potable water. Because of its lower productivity, it is not popularly used. Numbers of works are under taken to improve the productivity and efficiency of the solar still. There are large numbers of PCMs that melt and solidify at wide range of temperatures, making them attractive in a number of applications. PCMs have been widely used in latent heat thermal storage systems for heat pumps, solar engineering and spacecraft thermal control applications. The use of PCMs for heating and cooling applications for buildings has been investigated within the past decade. The experimental results computed in the field of water distillation process using solar energy in the presence of energy storage materials sodium sulphate and sodium acetate are discussed in this paper. Keywords: solar energy, saline water, distillation, phase change material.

Abstract: The main objective of this paper is to analyze the thermal performance of direct expansion solar assisted heat pump DX-SAHP(A) by numerical simulation in MATLAB and comparing it with the thermal performance of DX-SAHP(B) which has an optimized collector area and mass flow rate. Optimization is performed for high exergy efficiency using Particle Swarm Optimization (PSO) and Artificial Bee Colony (ABC) optimization technique. The flat plate collector of solar water heater is used as the evaporator with refrigerant (R22).With the optimized value of mass flow rate as 0.055 kg/sec, width as 0.03 m and diameter of riser tubes as 0.021 m the performance of the optimized system has a maximum COP of 6.85 which is greater than the COP of DX-SAHP(A) and the final water temperature of is obtained 100 minutes earlier in the optimized system i.e. DX-SAHP(B) with compressor work less than the system A

Abstract: This paper presents the undertaken attempt to perform techno –economic analysis of water cooled concentrating photo voltaic (CPV) system vis-à-vis solar photovoltaic (SPV) for an educational institution (BITS Pilani Hyderabad). With the help of preliminary and final energy auditing, the energy requirements for the 2800 hostel rooms of the campus were computed. Required PV & CPV systems’ techno-economic analyses to meet the energy loads were performed and a comparison was made to arrive at the possibility of using CPV systems. Area required for installing both the system was also performed.