Recent advancements in flat plate solar collector using phase change materials and nanofluid: a review.

Solar energy has emerged as one of the most promising sources of renewable energy to replace the current energy market. Flat plate solar collectors (FPSC) not only are one of the easiest collectors to produce and work with but also are cheap and economical. Due to this, extensive research has been done on FPSC to improve its efficiency and reliability. Some of the methods include using nanofluids to improve the heat transfer process, phase change materials to increase and maintain stable temperatures, or integrating the collector with additional components. This review article focuses on analyzing the recent improvements in FPSC, with a particular emphasis on the achieved efficiencies and temperatures in the studies. Additionally, it is aimed at updating the information in the current field, providing a comprehensive overview of the advancements in FPSC technology. Furthermore, the article explores the combined effects of nanofluids and phase change materials in photovoltaic/thermal (PVT) collectors, considering the resulting temperature enhancements. By critically evaluating the efficiency improvements and temperatures achieved through these approaches, this article is aimed at providing valuable insights into the state-of-the-art of FPSC and their potential for advancing solar energy utilization.

Experimental studies of different operating parameters on the photovoltaic thermal system using a flattened geometrical structure.

The efficiency of the photovoltaic (PV) cell reduces with an increase in solar irradiation. The reduction in the efficiency of the photovoltaic (PV) cell can be attributed to the increase in cell temperature. A novel design of a thermal absorber fabricated by a flat spiral tube is used to remove heat and decrease the cell temperature, thus forming the photovoltaic thermal system (PVTS). Water and titanium oxide (TiO2) nanofluid (NF) with a concentration ratio of 0.1% are used as the working fluid in the PVTS. The study has been carried out for the mass flow rates (mf) of 0.05, 0.066, and 0.083 kg/s. The reduction in the cell temperature is obtained to be 5.7 and 11.2 °C due to the cooling effect of water and TiO2 NF, respectively. The percentage increase in electrical efficiency is 2.93 and 5.28% by cooling using water and TiO2 NF, respectively. The hourly variation of the performance of the PVTS shows that TiO2 NF at 0.083 kg/s shows the highest photovoltaic thermal efficiency of 69.2% and thermal and electrical efficiency of 56.45 and 12.75%, respectively. The best coefficient of energy for TiO2 NF is 1.27 for a mf of 0.083 kg/s.

A relative study on energy and exergy analysis between conventional single slope and novel stepped absorbable plate solar stills.

The innovation of novel absorbing materials using composite materials and nanotechnology is of new trends for many researches. Here, the present study is concerning to enhance the distilled water productivity of a proposed solar still (PSS) using novel absorbing materials. The absorbing material is composed of chitosan (obtained from waste shrimp shells), ethylene diamine tetraacetic acid (EDTA), and Chrysopogon zizaniodes (Vetiver). The combination of these materials is coined as CHEDZ, and it acts as a super absorbent polymer that is coated on the stepped solar still. Evaporation rate increases due to this absorbent, which further increases the yield of the still. In this present study, the PSS is compared with the conventional solar still (CSS) for the use of assessing the yield of freshwater in the same atmospheric circumstance. The experimental setup was performed through the period from December to February 2020 in the Indian climatic condition. The freshwater productivity was improved to 3.05 L/day while the yield of the CSS is 2.47 L/day. The increase in efficiency obtained from a PSS is 39.71% more than the productivity attained from the CSS. The energy efficiency of the PSS is 18.34% and the exergy efficiency is 0.45%.

Performance enhancements of conventional solar still using reflective aluminium foil sheet and reflective glass mirrors: energy and exergy analysis.

Many researchers are seeking simple and successful solutions to increase the output from the solar distiller. In this research work, reflective mirrors and reflective aluminium foil sheet were fixed on inner surfaces of the single-slope solar distiller, leading to more water production. The presence of reflective mirrors and reflective aluminium foil sheet on inner surfaces of the solar distillate permits the reflection of solar radiation falling inside the basin. Experiments were carried out on three stills: the first distiller is conventional solar still with black painted walls (CSS-BPW); the second distiller is conventional solar still with reflective aluminium foil sheet walls (CSS-RAFW); and the third distiller is conventional solar still with reflective glass mirror walls (CSS-RGMW). The maximum total drinking water productions from the CSS, CSS-RAFW and the CSS-RGMW are 3.41, 5.1 and 5.54 kg/m2, respectively. Compared to the CSS-BPW, the production of drinking water was increased by 68.57% when using the reflective glass mirrors and 48.57% when using the reflective aluminium foil sheet.