News and recent developments
1. Ishan Purohit and Pallav Purohit (2009), "Instrumentation error analysis of a box-type solar cooker", Energy Conversion and Management, Vol. 50, No. 2, pp. 365-375.
- In order to certify the performance of a box-type solar cooker, thermal performance is evaluated in terms of two figures of merit viz. F1 and F2 (IS 13429:2000). The acceptable criterion to make the solar cooker eligible for ISI mark is that the value of F1 should not be less than 0.12, and that of F2 should be greater than 0.40. Further, the solar cooker is classified as Grade A if the value of F1 is determined to be 0.12 or higher; otherwise, the solar cooker is classified as Grade B. Determination of F1 and F2 comprises measurements of the temperature of cooking tray, water temperature and ambient air, solar irradiance, and other associated parameters. The effect of accuracy obtained in these measurements assumes significance in the perspective of grading of solar cookers.
- In the present work, an attempt has been made to analyze the effect of instrumentation on F1 and F2, which is normally employed for testing and standardization of solar cookers. The analysis is supported by a large number of outdoor tests conducted on a box type solar cooker under stagnation as well as load test conditions. It is observed that the variation of absolute value of error in F1 and F2 could be in the range of 0.002–0.003 and 0.015–0.033, respectively. This corresponds to errors of the order of 2.5–3.0% in the evaluation of F1 and 5.0–6.0% in F2.
2. Ishan Purohit and Pallav Purohit (2009), "Instrumentation error analysis of a paraboloid concentrator type solar cooker", Energy for Sustainable Development, Vol. 13, No. 4, pp. 255-264.
- An effective quality control is essential for a large-scale dissemination of solar thermal technologies on the products being offered by the industry to the end users. For this, there is a need to establish test procedures and methodologies for producing performance characteristic parameters, which could provide an equitable basis for comparison of performances of these products. At present, paraboloid concentrator type solar cooker technology is moving towards the phase of commercialization in India. For the thermal performance evaluation of paraboloid concentrator type solar cooker, Mullick et al. (1991) developed a test procedure that essentially recommends determination of optical efficiency factor (F′η) and heat loss factor (F′U) based on heating and cooling tests. Further a test method has been proposed by Funk (2000) for testing of all kind of solar cookers that characterizes the performance of solar cooker by two parameters, namely, adjusted cooking power (P) and overall heat loss coefficient (U) as obtained from heating test. These are the only test methods available for testing of paraboloid concentrator type solar cooker.
- The present communication analyzes the effect of instrumentation, on the values of F′η, F′U, P and U, which is supported by a large number of outdoor tests conducted on a paraboloid concentrator type solar cooker under heating and cooling test conditions. The role of individual associated parameters on F′η, F′U, P and U has been analyzed along with the estimation of overall error in these values due to the error in the determination of associated parameters. Though the maximum attainable accuracy in determining F′U varies from 1.15% to 0.65% (for loads of 1.0 to 8.0 kg), the associated error in the determination of F′η is quite high viz. 5.13% to 5.04% for the same load conditions. Similarly, the maximum attainable accuracy in the determination of standardized cooking power has been observed from 4.98% to 5.02% under the load conditions from 1.0 to 8.0 kg.
3. Ishan Purohit and Pallav Purohit (2008), "Effect of instrumentation error on the first and second figures of merit (F1 and F2) of a box-type solar cooker", International Journal of Ambient Energy, Vol. 29, No. 2, pp. 83-92.
4. Ishan Purohit and Pallav Purohit (2007), "CDM potential of box type solar cookers in India", International Journal of Ambient Energy, Vol. 28, No. 1, pp. 27-38.
5. Ishan Purohit and Pallav Purohit (2007), "Instrumentation error analysis of paraboloid concentrator type solar cooker", International Conference on Recent Trends in Mechanical Engineering (ICRTME-2007), Ujjain, India.
6. Ishan Purohit, Pallav Purohit and B.S. Negi (2006), "Design and testing of a box type solar cooker employing non-tracking planar reflectors", Solar Cookers International (SCI), Granada, Spain.
7. Pallav Purohit and Axel Michaelowa (2006), "CDM Potential of Solar Energy Technologies in India", World Renewable Energy Congress (WREX – IX), Florence, Italy.
8. Pallav Purohit and Tara Chandra Kandpal (2002), "Social cost benefit analysis of box type solar cooker", World Renewable Energy Congress (WREC-VII), Cologne, Germany.
Dr. Pallav Purohit
International Institute for Applied Systems Analysis (IIASA)
Atmospheric Pollution and Economic Development (APD)
Schlossplatz 1, A-2361 Laxenburg