Concentrator-assisted solar still for improving freshwater yield: an experimental approach.

The present experimental study aims to make advancements in the daily production of freshwater by a single solar still, with the ultimate goal of increasing its efficiency. The experiment was carried out in the solar still with and without integration at four different water masses within the basin, and metrics such as water, glass, basin temperature, and drinkable water generated were measured. The results showed that the daily distillate collected from the integrated system using 2.5 kg/h of mass flow in the parabolic concentrator produced 2.99 kg at the minimum water mass of 20 kg placed in the basin. When the flow velocity of water in the parabolic concentrator is raised from 2.5 to 5 kg/h, the amount of freshwater generated decreases from 2.99 to 2.66 kg. Compared to traditional single slope solar still, the potable water generated increases by roughly 18.24, 18.29, and 18.33% for water mass of 30, 40, and 50 kg, respectively, with the mass flow rate of water in the serpentine tubes as 2.5 kg/h. The results also reveals that, in addition to the PTC collector, the mass flowrate of fluid in the serpentine tube arrangement submerged in the basin affects daily solar efficiency. There is a significant reduction of about 1-2.3% in the daily efficiency of the system with increased mass flow rate of fluid in the serpentine tube arrangement. Similarly, the daily efficiency in all the cases reduces with increased water depth.

Analysis of a solar still with photovoltaic modules and electrical heater - Energy and exergy approach.

The availability of drinkable water, along with food and air, is a fundamental human necessity. Because of the presence of higher amounts of salt and pollution, direct use of water from sources such as lakes, sea, rivers, and subsurface water reservoirs is not normally suggested. Solar is still a basic technology that can use solar energy to transform accessible waste or brackish water into drinkable water. Exergy analysis is a strong inferential technique for evaluating the performance of thermal systems. Exergy is becoming more popular as a predictive tool for analysis, and there is a rising interest in using it. In this paper, performance analysis on the aspect of energy and exergy from the proposed solar still (PSS) (conventional solar still with the photovoltaic modules-AC heater) was analyzed on three different water depths (Wd) conditions (1, 2, and 3 cm). Using a solar still with an electric heater, the daily potable water production was found as 8.54, 6.37, and 4.43 kg, for the variations in water depth (Wd) of 1, 2, and 3 cm respectively. The energy and exergy efficiency of the PSS at the Wd of 1, 2, and 3 cm were 75.67, 51.45, and 37.21% and 5.08, 2.29, and 1.03%, respectively. At 1 cm Wd, PSS produced the maximum freshwater yield as compared to the other two water depths. When the Wd is increased from 1 to 2 cm and from 1 to 3 cm, the yield is decreased up to 27.3 and 52.7%, respectively. Similarly, the energy and exergy efficiency is decreased up to 36.8 and 53.2% and 50.4 and 80.6%, respectively. The water cost of the modified solar still is calculated as 0.028 $/kg for the least water thickness.

Performance enhancement of solar photovoltaic system for roof top garden.

The photovoltaic (PV) for irrigation system is an emerging technology to harness the solar energy. The performance of the PV modules depends on the incident solar radiation, geographical location, and the surface temperature of the modules. The performance of the PV system needs to be monitored by manually or embedded controllers. The commercially available technologies for monitoring the system are costlier and need to be optimized. The Arduino controller is used to monitor the performance of the photovoltaic (PV) system in Coimbatore (11.016° N, 76.9558° E), Tamilnadu, India. The PV surface temperature is monitored and controlled by flowing the water above the module by setting the mean ambient temperature as a reference temperature 34 °C when the system exceeds the reference temperature. PV surface temperature is reduced up to 16°C thus improved the electrical efficiency by 17% compare to the reference module. The Arduino controller control the relay to switch on the motor to control the mass flow rate of the water at 0.0028kg/s. The various parameters are measured such as voltage, current, and solar radiation of the location and analyzed. The estimated cost of monitoring system and various sensor is 10$ which cost comparatively 50% lower than the other PV monitoring controllers. This method can be employed in the medium and large-scale irrigation system.

Energy and exergy efficiency analysis of solar still incorporated with copper plate and phosphate pellets as energy storage material.

In this work, a new attempt was made to study the behavior of the conventional solar still (CSS) by adding a black-painted copper plate and phosphate pellets. Therefore, the performance of the three solar stills has been studied and compared. The first is the CSS, and the second is the modified solar still (MSS). The MSS performance was tested using black-coated copper plate (measuring 49 × 49 cm and 0.2 cm thick) with and without phosphate pellets and compared to the CSS in the similar climatic conditions. The results showed that the combination of black coated copper plate and the inclusion of phosphate pellets improved the evaporation rate and daily productivity. During the experiments, yields using black coated copper plate without and with phosphate pellets were 14.96% and 29.53% greater than the CSS. The effectiveness of the CSS, MSS with copper metal plate (MSS-CP), and MSS with copper metal plate with phosphate pellets (MSS-CP and PP) are around 30.23, 35.3, and 41.44%, respectively.