Heat transfer and hydraulics for a novel receiver pipe of solar parabolic trough: a computational approach.

The effect of symmetrical convex-concave corrugations on receiver pipe of a parabolic trough solar collector is numerically investigated. Twelve distinct geometrically configured receiver pipes with corrugations have been examined for this purpose. The computational study is conducted for varying corrugation pitch (4 mm to 10 mm) and height (1.5 mm to 2.5 mm). Heat transfer enhancement, flow behavior, and overall thermal performance of fluid moving through a pipe under non-uniform heat flux condition are all determined in this work. The Reynolds number ranges from 5000 to 50,000. The findings reveal that presence of corrugations leads to axial whirling and vortices in the receiver pipe, thus enhancing the heat transfer. The receiver pipe having corrugations of 8 mm pitch and 2 mm height gave the best results. The maximum enhancement in average Nusselt number over smooth pipe has been observed as 28.51%. In addition, relationships of Nusselt number and friction factor against selected design parameters and operating conditions are also displayed as correlations.

Review on agrophotovoltaic systems with a premise on thermal management of photovoltaic modules therein.

Agrophotovoltaics (APV) is the coexistence of solar photovoltaics (PV) and agriculture on the same piece of land. Although the concept of APV is known for the last two decades, its actual penetration in society is inconsiderable. The objective of the current article is to discuss the various APV systems explored in the past and to highlight the futuristic APVs. Furthermore, this study presents the review of the available experimental work on the performance and environmental and techno-economic aspects of the APV systems. The key features, crop selection criteria, feasible crops for Indian climatic conditions, and the future research directions of APV systems have been summarized. Furthermore, apart from the known techno-economic benefits of APV, a premise on its another utility for the thermal management of the solar PV modules by crops' natural transpiration cooling has been presented in this study. A theoretical study demonstrates the gain in the electrical output of the solar PV plant as compared with the conventional PV installation. The theoretical study has been carried out considering the meteorological data of Nagpur (21.1458° N, 79.0882° E). The estimation has been carried out using Nominal Operating Cell Temperature (NOCT) model, NREL irradiance database-NSRDB, and System Advisor Model (SAM). An experimental study has been conducted on APV systems with a 2-kW solar PV plant and tomato crops to investigate its actual performance. The study shows an increment of 17.96% in the daily energy generation as compared with the conventional solar PV power plant.

Cooling Performance of a Novel Circulatory Flow Concentric Multi-Channel Heat Sink with Nanofluids.

Heat rejection from electronic devices such as processors necessitates a high heat removal rate. The present study focuses on liquid-cooled novel heat sink geometry made from four channels (width 4 mm and depth 3.5 mm) configured in a concentric shape with alternate flow passages (slot of 3 mm gap). In this study, the cooling performance of the heat sink was tested under simulated controlled conditions.The lower bottom surface of the heat sink was heated at a constant heat flux condition based on dissipated power of 50 W and 70 W. The computations were carried out for different volume fractions of nanoparticles, namely 0.5% to 5%, and water as base fluid at a flow rate of 30 to 180 mL/min. The results showed a higher rate of heat rejection from the nanofluid cooled heat sink compared with water. The enhancement in performance was analyzed with the help of a temperature difference of nanofluid outlet temperature and water outlet temperature under similar operating conditions. The enhancement was ~2% for 0.5% volume fraction nanofluids and ~17% for a 5% volume fraction.