Experimental study of the influence of glass cover cooling using evaporative cooling process on the thermal performance of single basin solar still

Acute shortage of drinking water has been on the rise owing to increasing population as well as shortage of drinkable water. Generation of potable water using passive solar stills is among the simplest and easier devices which make use of solar heat energy. However, the output of solar still is generally low owing to greater heat loss and needs improvement. In this paper, an experimental analysis is carried out to determine the performance of passive solar still with glass cover cooling using cold water generated using passive evaporative cooling process. The cold water required for cooling the glass cover is obtained using evaporative cooling process in the water tank which is wound with wet cotton cloth wick. The cold water thus obtained is sprayed onto the top surface of glass cover. The experiment is carried out in the outdoor conditions of Dubai from 10:00h to 14:00h and the temperature recordings of basin plate, glass cover, basin water, ambient air and cooling water are noted for every 30 minutes. The results reveal that the average increase in condensation heat transfer coefficient is found to be about 20.8% higher in the presence of glass cover cooling and the distillate output is found to increase by about 3.32 times. The average still efficiency is found to be relatively higher in the presence of cooling which is about 7.3% higher in the presence of cooling. The cold water temperature generated through evaporative cooling process is about 20.4% lower as compared to ambient temperature. Thus, the cooling of glass cover using cold water obtained through evaporative cooling process is found to be effective in enhancing the thermal performance of single basin solar still system

Experimental investigation of humidification parameters using biomass-based charcoal as an alternative packing material

Due to the increase in human population, there is an ever-increasing demand for energy in different sectors which leads to environmental problems like climate change, rise in temperature, and global catastrophes. Cooling systems have become a very essential element in recent decades for mankind. The present system focuses on the design and fabrication of a counter-flow humidification setup which uses biomass-based charcoal as the packing material. Air velocity and water flow rate have been varied along with the density of charcoal. Output parameters such as a change in pressure (ΔP), Coefficient of performance (COP), evaporation rate (ER), humidification efficiency (HE), specific cooling capacity (SCC), and energy consumption (EC) are evaluated. Performance parameters obtained for charcoal are compared with that of standard Celdek Packing. Through experiments, it is found that humidification efficiencies for Celdek and charcoal packing are 77.45% and 57.40% respectively. The overall coefficient of performance obtained is 1.41 for charcoal and 3.17 for Celdek packing. Among the three densities which were considered, charcoal packing with a density of 400 kg/m3 exhibited higher performance with respect to COP, HE, ER, and SCC. Similarly, a water flow rate of 0.4 lpm gave a maximum performance and 0.7 lpm gave the least. It is concluded that charcoal can be considered one of the highly efficient biomass-based materials contributing to sustainable energy related to cooling applications

A novel study on a centrifugal humidifier for building cooling

Current work mainly deals with the design and construction of a centrifugal humidifier where the humidification and cooling are due to the soaking of the packing and the dispersion of the water from packing due to the centrifugal effect. Celdek pad 7090 is used as humidifying media, and water is used as a working substance. Experiments are performed by varying the water flow rate (WFR), air velocity (AV) and rotational packing speed. Performance parameters such as a difference in dry bulb temperature (DBT), difference in relative humidity (RH), saturation efficiency, coefficient of performance (COP) and evaporation rate (ER) are evaluated. Results showed that a water flow rate of 0.6 litres per minute (L/min), rotor speed of 150 rpm and air flow rate of 5 m/s gave the maximum performance. The current unit gave a maximum cooling efficiency, COP and ER equal to 79.23%, 5.24 and 0.90 g/s, respectively. Stationary and dynamic packing conditions are assessed where it is observed that the performance of dynamic packing is higher than that of the static case at all operating ranges. Celdek packing with dynamic conditions can be suitably applied to handle huge cooling loads, which encourages sustainable energy sources and reduces environmental pollution by limiting greenhouse gas emissions

Investigation on the performance of LDDS using biomass-based wood shaving as the packing material

Current work emphasises the counter flow liquid desiccant dehumidification system (LDDS) that uses a novel fabricated packing frame filled with biomass-based wood shaving material which used Calcium chloride as liquid desiccant. Experiments are carried out by varying mass flow rate, temperature, and concentration. Various dehumidification performance parameters such as moisture removal rate (MRR), Coefficient of performance, Dehumidification efficiency, mass transfer coefficient, change in humidity, and air temperature are studied. System gave an increased dehumidification performance at high concentration and low inlet temperature of the desiccant. Results revealed that when the flow rate is maintained between 0.5 and 0.55 Litres per minute, optimised performance parameters like energy consumption, MRR, COP, dehumidification efficiency are 662 Watts, 0.57 g/s, 2.7, 54% correspondingly