• Energy Research

This investigation examines mathematical modelling and experimental validation of two types of solar cookers: a box type with tilted intercept area equipped with one external reflector, and a parabolic cooker with a new configuration. Experiments were carried out with the cookers filled with two kilograms of water from 08:00 to 15:00 solar time. During the experiments, temperature gain in the box-type solar cooker was recorded at about 69.8 °C and in the parabolic-type solar cooker at 73.6 °C at the stagnation point. Direct normal irradiation in three distinct study areas was observed and found that it varied from 7.6 to 10 kWh m−2. Cooking pot placed in parabolic cooker was varied between 130 and 132 °C. Centre and south-east regions of study areas where global irradiation varied from 8 to 8.4 kWh m−2 were found suitable for box-type solar cooker and cooking pot temperature were found in the range of 100 °C to 105 °C. Mathematical modelling was programmed in MATLAB. The theoretical results were consistent with experiential data for both types of solar cookers. The effectiveness of the two cooker types can be deduced from the maps. It is found the use of the cookers in Northern and Southern regions of the country was not identical. Their suitability for cooking depends on the amount of solar radiations received.

AbstractIn this study, the design improvement was done in a shell and tube condenser for improved heat transfer and condensation of bio-oil vapour. The developed condenser has split shell and segmental baffles, which divide the shell in various zones and condensate collection points. The fast pyrolysis of wheat straw was done and the bio-oil vapour condensate collected from various outlets located at bottom of condenser shell. From experimental results it was found that production of bio-oil increased from 10.2 to 20.8% with increase in cooling water flow rate from 1000 to 2500 L/h; but, further increasing it beyond 2500 L/h provide marginal effects on production of bio-oil. The production of bio-oil increased from 15.2 to 20.7% as sweep gas flow rate was increased from 20 to 40 L/min at 2500 L/h of cooling water flow rate. But, further increase in sweep gas flow rate beyond 40 L/min resulted in to decrease in production of bio-oil. The novelty of this work is development of improved condenser with segmental baffles, which help in fractional condensation of bio-oil vapour, split shell for cleaning of outer surface of the cooling water tubes and compact design of condenser for optimal condensation of bio-oil.

The matured biogas production technology has led to the development of a number of biogas appliances for lighting, power generation, and cooking. The most promising among them is the biogas stove to meet the energy requirement for cooking application at domestic level. In this paper attempt has been made to design and develop a domestic biogas stove for meeting domestic cooking energy need. The performance of the stove was evaluated by using 2 m3 floating-type biogas plant. The thermal efficiency of developed stove was approximately 60.01%. Emission of carbon dioxide during combustion was measured and approximately 150–180 ppm.

Abstract Production of biogas and its utilization has several environmental benefits. It is a source of renewable energy, and its production is considered and manure producing factory. Biogas has wider industrial applications for this up-gradation is desirable. Up-gradation of biogas has drawn attention due to rapid increment in the price of fossil fuels. It has an open new window to replace natural gas. There are several up-gradation technologies are available and developed by many scientists. In this paper, attempts have been made to discuss various biogas purification technologies, which are widely used all over the world and major technologies, which are under development or research. The widely accepted technologies have been with more prominence on their operation, merits and demerits and their future scope are also discussed.

Abstract The environmental concern and availability of fuels are greatly affecting the trends of fuels for transportation vehicles. Biodiesel is one of the options as alternative transport fuel. This can be produced from straight vegetable oils (SVOs), oils extracted from various plant species and animal fats. Amongst many resources, availability and cost economy are the major factors affecting the large scale production of the biodiesels. The transesterification is one of the production processes for biodiesel, but incomplete esterification of all fatty acids in the starting material, lengthy purification methods such as water washing, relatively long reaction times, contamination and separation difficulties associated with co-production of glycerol and saponification of the starting material under certain reaction conditions are still being major challenges in the biodiesel production. Technological advancement and enhanced production methods are the demand of present time for large scale and sustainable production of biodiesel. In the present paper, comprehensive review on its production process, feed stock and its applications have been made. From many case studies it was concluded that engine performance with B20 biodiesel blends, and mineral diesel were found comparable.

The use of biomass cookstoves is widespread in the household sector of developing nations. Still, these stoves are inefficient and emit a lot of pollution, including gaseous pollutants such as CO, particulate matter, and other pollutants, due to insufficient thermal and combustion efficiency. The three pots improved cookstove was developed to enhance cooking efficiency for rural and low-income urban homes to address these issues. This cookstove consists of three burners that enable best heat utilization as it permits cooking on three pots simultaneously. Statistical analysis was made with ANOVA tool and t-test. The results were found significant at 5% level of significance. Moreover, developed cookstove has thermal efficiency and power rating of 34.45% and 1.72 kW, respectively. Typical CO, CO2, PM2.5 emissions were recorded as 8.8 ppm, 628 ppm, and 0.97 μg/m3, respectively based on findings of emission test. Although increased cookstove adoption is critical to addressing the public health issue, efforts to distribute cookstove technologies have been hampered, and adoption rates in many developing nations are reported to be very low. Thus, the policymaker should think about implementing such a cooking system in rural areas that minimizes the amount of fuelwood used and preserve the environment.

In this communication, detailed review of the solar thermal power plants based on the available solar concentrator systems like parabolic trough, parabolic dish, central tower, linear Fresnel reflector system are reported. The aim of the paper is to summarize overall research work being carried out worldwide on the thermodynamic performance evaluation of solar and other thermal power generation systems using different thermodynamic cycles. An attempt has also been made to assess as well as compare the energetic and exergetic performance of such thermal power generation systems. It has been observed that the efficiencies of the solar concentrator aided coal fired thermal power plant, and combined-cycle power plants are higher as compared to a solar alone thermal power plants. Furthermore, there is much scope in the areas of solar aided thermal power generation for further research with the aim of quantifying energy and exergy losses, and exergy destructions in the components of the solar thermal power generation systems.