Entropy Generation and Thermal Analysis of Nanofluid Flow Inside the Evacuated Tube Solar Collector

In the current investigation, the thermal and thermodynamic behavior of a buoyancy-driven evacuated tube solar collector has undergone precise evaluation, and the efficacy of nanoparticle dispersion in the base fluid has been scrutinized using computational fluid dynamics based on the finite volume method. The natural convection process was analyzed in different vertical sections of the absorber tube. The temperature and velocity distributions of water as the conventional working fluid and the nanofluid were compared at various cutting planes along the tube during the simulation time. In this problem, CuO nanoparticles with optimum thermal properties were suspended in the base fluid. According to the surveyed results, the temperature distribution analysis illustrates that the mean temperature of the tank experiences more enhancement when the nanofluid is used. The comparison of the heat transfer coefficient between two simulated cases shows the competency of utilizing CuO/water nanofluid in the thermal performance improvement of the collector. The results related to entropy generation assessment show that the irreversibility owing to fluid friction rises when the nanofluid is applied during the flow time. In contrast, the entropy generation of pure water owing to heat transfer surpasses the case with nanofluid.

Experimental Investigation on Evacuated Tube Solar Collector Using Biofluid as Heat Transfer Fluid

Bio-oil extracted from waste of different plant kernel was used as heat transfer fluid in evacuated tube solar collector. Thermal performance of the biofluids to the enhancement of the evacuated tube solar collector under varying weather conditions and experimental analysis was carried-out. Thermal analysis on the storage water tank temperature, outlet and inlet heat transfer fluid temperature, and heat gains by was studied. In addition, the biofluids thermophysical properties and degradation analysis was conducted and compared with conventional base-fluids. From the results the biofluids caused enhancement of heat gain in the collector receiver by 9.5%, 6.4% and 3.2% for moringa oleifera kernel oil (MOKO), date kernel oil (DKO) and palm kernel oil (PKO), respectively. The storage water tank temperature at night fall was 53, 49, 51 and 47oC, for the MOKO, DKO, PKO and water HTFs, respectively. The biofluids were thermal stable and with no degradation. The biofluids demonstrated potentials as heat transfer fluids in thermal applications but there are needs for more investigations on their enhancement with organically synthesized nano particles to preserve there no corrosive and toxicity nature, and experimental performance on heat exchangers after several heating cycles.

Numerical Assessment of an Innovative Design of an Evacuated Tube Solar Collector Incorporated with PCM Embedded Metal Foam/Plate Fins

The objective of this manuscript is to study the possibility of improving the thermal performance of an Evacuated Tube Solar Collector (ETSC) with the integration of a Phase Change Material (PCM) incorporated into metallic foam and fitted with plate fins. A 2D mathematical model has been proposed. Two types of metal foams (copper and nickel) were inserted. In addition, the effect of metal foam pore size of on heat transfer was studied. The results were acquired through numerical simulations of four different cases; namely, Case 1: pure PCM, Case 2: with metal foam, Case 3: with fins and Case 4: with metal foam and fins. The evaluation procedure involved observing the total change in Heat Transfer Fluid (HTF) temperature and melted PCM fraction during a single day. The results proved that the thermal performance of ETSC is improved considerably by inserting metal foam and fins simultaneously. The time required for the whole process is improved by almost 9% compared to the case of pure PCM, and 2% compared to the case of inserting only plate fins. Results revealed that the pore size of the metal foams slightly affects the dynamic process of heat storage/release in the ETSC/PCM system.

Experimental Investigation of a Single Basin -Single Slope Solar Still Coupled with Evacuated Tube Solar Collector

This work is an experimental investigation for single basin-single slope solar still coupled with an evacuated tube solar collector. The work is carried out under the climatic conditions of Baghdad city (33.2456º North and East latitude, 44.3337º longitude) through certain days of the months of the year 2019 to study the impact of using evacuated tube solar collector on the daily productivity and efficiency under the outdoors climatic conditions. It was found that using the evacuated tube solar collector increase daily productivity from 2.175 kg/ to 2.95 kg/ for 9 hours (35.63 %) for clear days, also an enhancement about 10.97 % in daily efficiency.