Of all the renewable sources of energy available, solar thermal energy is the most abundant one and is available in both direct as well as indirect forms. In order to increase the thermal performance of solar collectors, the multipurpose solar collectors were investigated experimentally by the storage tank of the conventional solar water collector is modified as riser tubes and header. It is fitted in the bottom of the solar air heater as an absorber in the normal air heater. The thermal performance of thermosyphon flat plate solar water heater was investigated on both summer and winter seasons. The maximum daily average of 72.05%, 0.0316 kg/sm2and 0.873 m/s were recorded for the relative humidity, mass flow rate and wind speed at summer season respectively. Corresponding figure at for winter was 19.5 % 0.0295 kg/sm2and 0.722 m/s respectively. A minimum daily average of 11.23% and 0.384 m/s for the relative humidity and wind speed respectively. These results show that the mass flow rate obtained was a function of solar radiation and relative humidity. The less humid the ambient air becomes, the higher the heat gained by the system hence higher water flow rate. The maximum value of relative humidity obtained is due to low solar radiation on winter season. The heat removal factor (FR) and collector efficiency factor (Fo) were found to be higher for Multipurpose solar water heater as compared to conventional solar water heaters for summer as well as winter season. These factors for Multipurpose solar water heater were more during summer and winter.

Paraboloidal dish concentrators need tracking the sun in the east-west and north-south direction continuously throughout the year. But this paper explains the method of intermittent tracking of the sun in the north-south direction with no tracking in the east-west direction for less energy yield. The frequency of tracking in the north-south direction is determined by the relationship between the variation in solar altitude angle and the size of the absorber in the Paraboloidal dish concentrator. A computer program in Visual BASIC is written to enable the detailed calculations of data for the analysis.© 2004 American Institute of Physics.

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Abstract. This report presents experimental platform based on the design, development and performance characteristics of direct steam generation by non-tracking solar paraboloidal dish concentrating system. The performance of the concentrator is experimentally investigated with the water circulated as heat transfer fluid. The system is fabricated with highly reflective aluminium foil sheet. The experimental setup is placed in open, and the tests were carried out. The collector's efficiency was noted. The results are encouraging to provide the data for developing steam generation for rural application. The concentrated heat is absorbed by a copper tube which is made up of coil in a curved shape and it is fixed on solar trace path in which, it is eliminates tracking the sun in the east west direction and optimal tracking of the sun in the north-south to obtain maximum solar energy. The experimental results are taken on summer and cloud free days. The test results were measured 215 o C with solar steam conversion efficiency is 60-70% measured.