Anil Kumar Patil

Sensible thermal energy storage offers numerous benefits but also has some inherent limitations. The present work compares the charging characteristics of a single tube sensible energy storage system (STSESS) with a multiple tube sensible energy storage system (MTSESS) for air as HTF by varying its inlet temperature and flow rate in the range of 45°C–75°C and 0.022–0.031 kg/s, respectively. MTSESS stores a larger quantity of energy with improved charging efficiency within the specified range of HTF temperatures and flow rates.

The heat exchanger performance is vital for attaining higher overall performance of the greenhouse heating system. The exergetic performance is evaluated for the heat exchanger using twisted tape inserts for greenhouse heating. Single, a set of two, and four twisted tapes of TR 2.5-3.5 are considered for the analysis by varying Reynolds number (Re) from 3000 to 15000. A set of two twisted tapes causes a decrease in total entropy generation up to Re of 7650 and increases beyond this value. The maximum and minimum values of the Bejan number are obtained for the smooth tube and the tube with twisted tapes (four) in “counter-swirl” orientation, respectively. The twisted tapes are feasible under the Reynolds number of 9042 based on the analysis of the entropy generation number. The minimum value of total entropy generation is obtained as 0.00035 for the four twisted tapes in counter-swirl orientation (FTT-COUS). The maximum exergy efficiency is observed for a twisted tape insert at a pitch ratio of 3.5.

To design a compact heat sink, a simplified geometry, enhanced heat dissipation, and the minimum pressure drop should be taken into consideration. With this objective, an experimental investigation has been conducted with the corrugated plate-fin heat sink by varying the relative radius of corrugation and relative corrugation pitch in the range of 0.16–0.31, and 0.06–0.16, respectively, for the Reynolds number range of 6000–14,000. Experiments were conducted on a corrugated plate-fin heat sink using an open-loop experimental system comprising a test section of a rectangular channel measuring 2300 mm long, 180 mm wide, and 80 mm high. The corrugated fin creates higher disturbances caused by multiple separations and reattachments in the flow and thereby yielding a higher localized heat transfer coefficient and enhanced heat transfer from the system. The maximum fin performance is found to be 5.87 for the corrugated plate-fin heat sink corresponding to the relative radius of corrugation and relative corrugation pitch of 0.16 and 0.125, respectively.