Solid Receiver Research Articles

Thermal performance of cubical receiver with trapezoidal ice-pot for melting of ice at high altitude regions based on Scheffler solar concentrator

ABSTRACT The thermal performance of cubical receiver with a trapezoidal ice-pot has been investigated with the aim to generate hot water by melting of ice at high altitude regions (Leh Ladakh). In the experimental set-up, one hollow mild steel cubical receiver (filled with heat transfer fluid) with the ice-pot and four different types of solid cubical receivers with the ice-pot are used to melt the ice with direct heating in minimum time. The radiations are focused on receiver with the help of a 1 m2 Scheffler concentrator that is exposed to the atmospheric situations of NIT Kurukshetra. The results from the designed set-up are obtained that the frozen ice at −4°C melts completely, converting into water and the maximum temperature of the water attained in hollow cubical receiver, solid receiver (granite), solid receiver (dholpur stone), solid receiver (concrete) and solid receiver (mild steel) is 42.5°C, 32.9°C, 49.5°C, 30.2°C and 52.7°C, respectively.

Trends and Opportunities in Direct-Absorption Solar Thermal Collectors

Efficient conversion of sunlight into useful heat or work is of increasing global interest. Solar-to-thermal energy conversion, as opposed to solar-to-electricity, is enabled by solar thermal collectors that convert sunlight into heat at some useful temperature. We review here recent developments in solar thermal energy conversion. Our emphasis is on “direct-absorption” solar thermal collectors, in which incident sunlight is absorbed directly by a working fluid. This contrasts with conventional solar thermal collectors where the sunlight strikes and is absorbed by a solid receiver, which then transfers heat to the working fluid. Both liquid-based and gas-based direct-absorption collectors are described, although liquid-based systems are emphasized. We propose that if “direct-absorption” technologies could be developed further, it would open up a number of emerging opportunities, including applications exploiting thermochemical and photocatalytic reactions and direct absorption of a binary fluid for absorption refrigeration.