Percorrer por autor "Sagade, Atul A."
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- Concentrating solar cookers in urban areas: establishing usefulness through realistic intermediate temperature rating and gradingPublication . Sagade, Atul A.; Apaolaza-Pagoaga, Xabier; Ruivo, Celestino; Carrillo-Andrés, AntonioConcentrating Solar Cookers (CSCs) are well-known for fast cooking and can significantly contribute to attaining the United Nation's sustainable development goals. CSCs attain intermediate temperatures (120-240 degrees C) and are suitable for several cooking applications. The realistic rating and grading of CSCs is inevitable for establishing their usefulness in urban areas, which is the main objective of the present work. This paper reveals the experimental results of two existing concentrating solar cookers with different geometries and aperture areas. The first cooker is a shallow satellite antenna parabolic dish, and the other is a small deep parabola. Cooker Opto-thermal Ratio (COR) acts as a thermal performance parameter, and glycerin as a test load for their performance evaluation.The mean values of COR for the cookers, CSC1, and CSC3, are 0.180 and 0.092, respectively. The typical theoretical values of maximum achievable fluid temperature are 192.9 and 113.9 degrees C, respectively, and that for reference time are 23.8 and 60.5 min for CSC1 and CSC3, respectively. COR identifies the variation in the performance of CSCs based on a design change. The objective parameters enable realistic intra-cooker performance comparison of the CSCs at intermediate temperatures. The results depict that the existing designs of CSCs can be graded appropriately using COR and provide new insights into their performance at intermediate temperatures realistically. TPP-based realistic rating and grading of existing designs of solar cookers enable their effortless selection as per end-user requirements and help in the faster propagation of solar cooking technology in urban and semi-urban areas.
- Experimental determination of effective concentration ratio for two different designs of concentrating solar cookersPublication . Sagade, Atul A.; Apaolaza-Pagoaga, Xabier; Ruivo, Celestino; Carrillo-Andrés, AntonioThe concentration ratio is most influential characteristic of the solar concentrators, impacting on its opto-thermal performance. Hence, concentration ratio's, realistic and quantificable measurement is essential. Therefore, this paper reveals the usefulness of the determination of an effective concentration ratio (Ceff) for a satellite antenna dish and Parvati concentrating solar cookers. Open and closed reflector open sun cooling tests were performed to determine the cooker opto-thermal ratio (COR). A thin black cloth used over each reflector neutralizes the effect of the reflection of solar radiation in the closed reflector tests. Subsequently, the COR values for these two types of tests enables the determination of the Ceff. Some corrective actions are suggested to eliminate the errors occurring during open reflector open sun cooling tests. Results show that the values of the Ceff for the satellite dish and Parvati cookers are 7.34 and 3.61, respectively. The determination of Ceff values enables commenting on its effective and realistic value, the role of the concentrator's reflecting surface in the concentration effect, and the degradation of the reflector surface. Thus, the Ceff is a practical indicator for assessing the impact of optical characteristics of the reflecting surface of the CSCs.
- Performance of solar funnel cookers using intermediate temperature test load under low sun elevationPublication . Apaolaza-Pagoaga, Xabier; Sagade, Atul A.; Ruivo, Celestino; Carrillo-Andrés, AntonioSolar funnel cookers can be designed as attractive and affordable low-cost devices accessible to people in all continents of the world regardless of their walk-in life. The present work is aimed to investigate the applicability of funnel cookers to attain the temperature in excess of the boiling point of water. It widens their acceptability for cooking and opens new opportunities for technological developments in such designs of solar cookers. Two identical designs of funnel cookers, FC1 and FC2, have been tested with appropriately sized identical cooking pots and glass enclosure to serve the purpose. Cooker FC2 is tested with a glass enclosure only, while a glass enclosure is not used in FC1. Glycerine is used as a test load. Cooker Opto-thermal Ratio (COR) as a thermal performance parameter and overall cooking efficiency are used to compare the performance of the two funnel cookers. It is shown that the temperature of the test load in the cooker FC2 can reach 140 to 150 degrees C. So, this funnel cooker design can be preferred for cooking food at a relatively high temperature over the boiling point of water. The experimental results show that: i) the mean values of the Cooker Opto-thermal Ratio for cookers FC2 and FC1 are estimated to be 0.157 and 0.110 (m2 degrees C)/W, respectively, and ii) the values of the overall cooking efficiency for cookers FC2 and FC1 are estimated to be 11.8% and 10.2%, respectively.