Demonstration plant of a multi wick solar still

A solar distillation plant of capacity 70 litres/day (annual average) has been installed at the Centre of Energy Studies, Indian Institute of Technology, New Delhi, India. The system has been working for the last 1 year, and its performance is found to be satisfactory. It meets the requirements of distilled water in the Institute.     

Design and development of a solar cooker cum drier

A solar cooker cum drier has been designed and developed. In designing this unit, optimum booster-collector geometry has been considered in order to eliminate the requirement of sun tracking. Tilting arrangements have also been provided to capture more solar energy. This dual purpose device has been found useful for cooking food and dehydrating fruit or vegetables.     

Development of a feasibility prediction tool for solar power plant installation analyses

The solar energy becomes a challenging area among other renewable sources since the solar energy sources have the advantages of not causing pollution, having low maintenance cost, and not producing noise due to the absence of the moving parts. Although these advantages, the installation cost of a solar power plant is considerably high. However, feasibility analyses have a great role before installation in order to determine the most appropriate power plant site. Despite there are many methods used in feasibility analysis, this paper is focused on a new intelligent method based on an agglomerative hierarchical clustering approach. The solar irradiation and insolation parameters of Central Anatolian Region of Turkey are evaluated utilizing the intelligent feasibility analysis tool developed in this study. The clustering operation in the tool is performed by using the nearest neighbor algorithm. At the stage of determining the optimum hierarchical clustering results, Euclidean, Manhattan and Minkowski distance metrics are adapted to the tool. The achieved clustering results based on Minkowski distance metric provide the most feasible inferences to knowledge domain expert according to other distance metrics.     

Design optimization of solar cooker

Various designs of solar cookers have been theoretically investigated with a view to optimize their performance. Starting from a conventional box type cooker, various combinations of booster mirrors have been studied to arrive at a final design, aimed at providing a cooker, which can be fixed on a south facing window (for countries of northern hemisphere, mainly situated near the tropic of Cancer). This cooker, with a rear window opening, may provide higher cooking temperature for a fairly large duration of the day. Two or three changes in positions of the side booster mirrors, without moving the cooker as a whole has been proposed. The new design has been experimentally implemented and compared with a conventional box type solar cooker. Besides the convenience of a rear window opening, the cooker provides temperatures sufficiently high to enable cooking two meals a day.     

Critical evaluation of solar chimney power plant performance

This paper evaluates the influence of a recently developed convective heat transfer equation, more accurate turbine inlet loss coefficient, quality collector roof glass and various types of soil on the performance of a large scale solar chimney power plant. Results indicate that the new heat transfer equation reduces plant power output considerably. The effect of a more accurate turbine inlet loss coefficient is insignificant, while utilizing better quality glass enhances plant power production. Models employing Limestone and Sandstone soil produce virtually similar results to a Granite-based model. The plant collector height is found to differ from previously obtained optimal values.     

Economic analysis of a G.I. sheet multiwick solar distillation plant

On account of the energy crisis, several types of solar energy devices have been developed and marketed in various parts of the world with varying degrees of thermal performance. The economic aspect of these solar energy devices becomes more significant when they replace those devices which use conventional fuels. In this paper, an economic analysis of one of the solar energy devices, namely a G.I. sheet multiwick solar distillation plant, has been presented taking into account the various factors, viz. the lifetime of the system, salvage values of the system, interest rate and maintenance cost.     

Partial geometric similarity for solar chimney power plant modeling

A solar chimney power plant derives its mechanical power from the kinetic power of the hot air which rises through a tall chimney, the air being heated by solar energy through a transparent roof surrounding the chimney. In our previous studies, the achievement of complete dynamic similarity between a prototype and its models imposed the use of different solar heat fluxes between them. It is difficult to conduct an experiment by using dissimilar heat fluxes with different physical models. Therefore, this study aimed to maintain dynamic similarity for a prototype and its models while using the same solar heat flux. The study showed that, to achieve the same-heat-flux condition, the roof radius between the prototype and its scaled models must be dissimilar, while all other remaining dimensions of the models are still similar to those of the prototype. In other words, the models are ‘partially’ geometrically similar to the prototype. The functional relationship that provides the condition for this partial similarity is proposed and its validity is proved by scaling the primitive numerical solutions of the flow. Engineering interpretations of the similarity variables are also presented.     

Energy parameters of a solar car for Jordan

All parameters related to car energy were investigated in this work, and the power basics of a car design powered by solar energy are laid down. Year-round weather conditions, car weight, road roughness and road inclination were taken as variable parameters used to calculate the car speed and working hours (year round). Fixed parameters taken for the design were: a photovoltaic generator area of 6 m², car length of 5 m, car width of 1.8 m and maximum power output of 480 W/person with a maximum of two persons. These parameters depended on the regulations of “Tour de Sol '91”. Calculations depended on Amman weather conditions. Sixteen ASI 16-200 ARCO SOLAR INC. model photovoltaic modules were used, with three DELCO 1150 lead acid batteries connected to a permanent magnet DC motor of 0.8 hp. This car can run at different speeds 3–6 hours/day on 200 days/year.     

A review of solar thermal technologies

The use of solar energy in recent years has reached a remarkable edge. The continuous research for an alternative power source due to the perceived scarcity of fuel fossils is its driving force. It has become even more popular as the cost of fossil fuel continues to rise. The earth receives in just 1 h, more energy from the sun than what we consume in the whole world for 1 year. Its application was proven to be most economical, as most systems in individual uses requires but a few kilowatt of power. This paper reviews the present day solar thermal technologies. Performance analyses of existing designs (study), mathematical simulation (design) and fabrication of innovative designs with suggested improvements (development) have been discussed in this paper.     

Design of electronic optimizer for solar electric drive system

There has been considerable interest in the use of solar electrical converters for supplying electric drive motors in pumping schemes for rural areas. The optimum control of solar electric drive motors is desirable because it leads firstly, to higher apparent efficiency of solar energy conversion, and, secondly, to reduced cost per useful watt. Although the ‘fuel’ for solar drives is free, the cost of solar cells is high. Optimization means that smaller areas of solar panels are required, thus reducing the overall cost of the solar drive system. The present investigation has been directed towards the development of a reliable electronic controller, which would ensure stable and optimal performance characteristics of solar electric-powered pumping scheme over a broad range of operating conditions. The design goals are low cost, reasonable accuracy, control capability and efficient utilization of the electrically converted solar power. The developed electronic optimizer provides constant voltage operation of the solar generator so that maximum power can be delivered to the drive motor for any light intensity. The main part of the optimizer is a servo chopper. The chopper operation is automatically adjusted so that the overall system efficiency is always maintained at a maximum value. Details of the electronic optimizer circuits are given and the overall system performance is investigated. Valuable information for the design and operation of the solar electric drive system with the electronic optimizer is gained from this analysis.     

Design of a commercial solar hot water system

The paper critically evaluates the design and performance of a commercial hot water system. These systems are installed in IIT Delhi hostels mainly for cooking and washing utensils. In some of these systems, heat exchangers are also used. In specific terms, one can regard the thermal efficiency and the maximum hot water temperature as indicators of the performance of the system. Hence different parameters of the heat exchanger and the number of collector panels directly affect the performance of the system. In the paper, an energy balance for different components of the system under steady state conditions is primarily investigated. It is found that excellent agreement exists between experimental and theoretical results for the proposed design parameters.     

Serial grey-box model of a stratified thermal tank for hierarchical control of a solar plant

The ACUREX collector field together with a thermal storage tank and a power conversion system forms the Small Solar Power Systems plant of the Plataforma Solar de Almería, a facility that has been used for research for the last 25 years. A simulator of the collector field produced by the last author has been available to and used as a test-bed for control strategies. Up to now, however, there is not a model for the whole plant. Such model is needed for hierarchical control schemes also proposed by the authors. In this paper a model of the thermal storage tank is derived using the Simultaneous Perturbation Stochastic Approximation technique to adjust the parameters of a serial grey-box model structure. The benefits of the proposed approach are discussed in the context of the intended use, requiring a model capable of simulating the behavior of the storage tank with low computational load and low error over medium to large horizons. The model is tested against real data in a variety of situations showing its performance in terms of simulation error in the temperature profile and in the usable energy stored in the tank. The results obtained demonstrate the viability of the proposed approach.     

Design and analysis of low-reflection grating microstructures for a solar energy absorber

The problem of calculating the photo-induced current in an n⁺p junction solar cell with a microstructure grating on the top is formulated. For the case where useful absorption regions lie below the grating a closed solution of the problem is obtained, in which the carrier photo-generation rate is calculated using a full-vector electromagnetic simulation technique. Two structures: filled lamellae grating and overlayer, and filled V-groove grating and overlayer are considered. The first structure is optimized with respect to the integral photo-current and the second with respect to reflection loss. Both optimized structures are much less reflective and more efficient than an optimized flat-surface Si–SiO₂ layer cell.     

Design of a new solar dryer system with swirling flow for drying seeded grape

In this study solar energy supported, swirling flow new drying system is designed and artificial drying of grapes grown around Elazığ/Turkey is investigated. With the developed swirling flow dryer with airy solar collector it is examined that drying occurs homogenously and lower moisture values are obtained in when compared with classical drying system. Also it is found that with an increase in the drying air velocity decreases drying time. When air directing elements are placed inside drying chamber and rotating element to the entrance, it is examined that drying time gets shorter compared to that of natural drying. Thus, drying time which is 200 h in natural conditions decrease to 80 h with an air velocity of 1.5 m/s with the developed solar energy supported swirling flow dryer.     

Parametric analysis of a solar energy based multigeneration plant with SOFC for hydrogen generation

Renewable energy-based hydrogen production plants can offer potential solutions to both ensuring sustainability in energy generation systems and designing environmentally friendly systems. In this combined work, a novel solar energy supported plant is proposed that can generate hydrogen, electricity, heating, cooling and hot water. With the suggested integrated plant, the potential of solar energy usage is increased for energy generation systems. The modeled integrated system generally consists of the solar power cycle, solid oxide fuel cell plant, gas turbine process, supercritical power plant, organic Rankine cycle, cooling cycle, hydrogen production and liquefaction plant, and hot water production sub-system. To conduct a comprehensive thermodynamic performance analysis of the suggested plant, the combined plant is modeled according to thermodynamic equilibrium equations. A performance assessment is also conducted to evaluate the impact of several plant indicators on performance characteristics of integrated system and its sub-parts. Hydrogen production rate in the suggested plant according to the performance analysis performed is realized as 0.0642 kg/s. While maximum exergy destruction rate is seen in the solar power plant with 8279 kW, the cooling plant has the lowest exergy destruction rate as 1098 kW. Also, the highest power generation is obtained from gas turbine cycle with 7053 kW. In addition, energetic and exergetic efficiencies of solar power based combined cycle are found as 56.48% and 54.06%, respectively.     

Performance of a solar dryer using hot air from roof-integrated solar collectors for drying herbs and spices

A solar dryer for drying herbs and spices using hot air from roof-integrated solar collectors was developed. The dryer is a bin type with a rectangular perforated floor. The bin has a dimension of 1.0 m×2.0 m×0.7 m. Hot air is supplied to the dryer from fiberglass-covered solar collectors, which also function as the roof of a farmhouse. The total area of the solar collectors is 72 m². To investigate its performance, the dryer was used to dry four batches of rosella flowers and three batches of lemon-grasses during the year 2002–2003. The dryer can be used to dry 200 kg of rosella flowers and lemon-grasses within 4 and 3 days, respectively. The products being dried in the dryer were completely protected from rains and insects and the dried products are of high quality. The solar air heater has an average daily efficiency of 35% and it performs well both as a solar collector and a roof of a farmhouse.     

Design,development and testing of an improved multipurpose solar energy device

This paper reports the design, development and testing of an improved multipurpose solar energy device. The novel feature of the device is that it can be used as a solar water heater and solar still simultaneously and, when required, as a solar cabinet dryer by incorporating minor changes.     

An experimental study on a finned type and non-porous type solar air heater with a solar simulator

The results of experiments performed on two non-porous solar absorber solar air heaters with and without fins have been reported in this communication. The experiments were performed under laboratory conditions. Air heaters with fins are seen to be more efficient in comparison to the air heater without fins for air flow rates ≤0.0388 kg/sec per m². The experimental results have been used to validate a simple theoretical model.     

INDITEP: The first pre-commercial DSG solar power plant

This paper presents the conceptual design of the first solar power plant using Direct Steam Generation (DSG) in a parabolic-trough solar field. Experience and know-how in the DSG process acquired during the DISS project were applied in designing the solar field of this plant. The 5-MWe plant is composed of a DSG parabolic-trough solar field connected to a superheated steam Rankine power cycle. The solar field produces 410 °C/70-bar superheated steam. Detail engineering of this plant is currently underway within the framework of the INDITEP project, which is promoted by a German-Spanish consortium with the financial support of the European Commission (Contract No. ENK5-CT-2001-00540). The main design objective is to assure high operational flexibility and reliability. This is the reason why a robust superheated steam turbine has been selected, though the efficiency of its power block is modest.     

Design and development of a simple solar dehydrator for crop drying

In this paper, a simple solar collector cum crop drying system is described. The categorical objectives of this paper are (1) to identify a suitable medium capacity solar drying system and (2) to study analytically and experimentally the performance characteristics of this newly fabricated solar drying system. The drying ratio, rehydration ratio, culinary and organoleptic characteristics, of Methi and Bhendi crops were studied and presented in this paper.