Humidification-Dehumidification Desalination System Powered by Simultaneous Air-Water Solar Heater

A humidification–dehumidification (HDH) desalination system requires thermal energy to desalt seawater. An environmentally friendly approach to obtain thermal energy is to utilize solar energy using solar collectors. Either seawater or air (or both) are typically preheated by HDH desalination systems before these fluids are conveyed to the humidifier column. Compared with preheating only air or water, preheating both is preferred because improved performance and higher productivity are achieved. Many researchers have proposed dual preheated HDH systems utilizing two separate solar heaters/collectors for simultaneous air–seawater preheating. In this study, dual-fluid preheating is achieved using a single solar collector. The proposed simultaneous air–water solar heater (SAWSH) is a modified flat-plate collector designed for simultaneously preheating air and seawater before the fluids reach the humidifier. A thermodynamic study was conducted using formulated mathematical models based on energy and mass conservation principles. Then, the dual-fluid heating HDH system is compared with HDH systems in which only air or only water is heated. This work found that the former outperformed the latter. The daily and monthly performance levels of the system in terms of the outlet temperatures of air and water, distillate rate, and gain output ratio were calculated using the weather data of the hot and humid climate of Jeddah City, Saudi Arabia.

IoT-based performance analysis of hybrid solar heater-double slope solar still

Remote monitoring of solar still systems is an interesting step for performance analysis and supervision. In this article, a monitoring system is developed and integrated to a solar still system. The parameters considered (such as air temperatures, relative humidity, etc) have been posted on a webpage via the Internet of Things (IoT) technique. For this, the ThingSpeak platform of the MathWorks is used. The results demonstrate that the ground water after desalination has practically the same chemical parameters values like mineral water (Nestle) and ordinary home drinking water. It has been also confirmed that by adding a solar preheater, the process of evaporation of saline water has been accelerated, which permits to improve efficiency the proposed prototype.

Techno-Economic Study of a New Hybrid Solar Desalination System for Producing Fresh Water in a Hot–Arid Climate

By taking advantage of the obtained experimental data, the impact of employing concentrating solar collectors, using an electric heater, and changing the water height in the basin on the performance of a hybrid solar still system was investigated. Eight different operating modes for the system were studied, while the daily freshwater production in addition to the cost per liter (CPL) was considered as the performance criteria. According to the results, the best height of water in the basin is 10 mm. It is the lowest examined height. Moreover, it was found that using the hybrid system with both electric heater and concentrating solar heater brings considerable improvements compared to the other investigated operating modes. For the climatic condition of Sirjan, Iran, which is where the experiments were performed, and water height in the basin of 10 mm, using the hybrid system in the active mode results in 8178 mL/m2 of fresh water production, and a CPL of $0.04270 per liter.

Eco-Friendly and Economical Solar Heater Design Using Internal Structure and Phase Change Materials

Indoor heating systems currently used are highly dependent on fossil fuels; hence, it is urgent to develop a new heating system to achieve carbon zero-emission. A solar air heater is eco-friendly because it generates nearly zero greenhouse gases. In this study, a parametric study was conducted for optimizing solar air heater design applicable to indoor heating. Installing the internal structure in the solar heater changes the interior flow characteristic, resulting in the air temperature increased by about 14.2 K on average compared to the heater without the internal structure. An additional case study was carried out to optimize the ideal quantity of phase change materials (PCM) in terms of mass fraction and heat capacity for various operating conditions. An excessive amount of PCM (e.g., 66% of the storage space filled with PCM) deteriorates the performance of the air heater unless the entire PCM could be melted during the daytime. After heating, the air temperature was maintained the longest when only 33% of the internal space was filled with PCM. The solar air heater can fully replace or partly assist a conventional heater for indoor heating, and it could reduce approximately 0.6 tCO2 per year.

Long-Term Performances and Technoeconomic and Environmental Assessment of Al2O3/Water and MWCNT/Oil Nanofluids in Three Solar Collector Technologies

Bringing together nanofluids and solar collectors has been widely discussed without any major advance or long-term study being carried out. In this context, this paper provides a useful feasibility study to help future decisions in using nanofluids in Solar Water Heating Systems (SWHSs) in different locations. The performances of SWHSs using the nanofluid-based flat plate solar collector (FPSC), evacuated tube collector (ETC), and compound parabolic collector (CPC) under the Mediterranean, arctic, and desert climate conditions are presented and discussed. The analysis is carried out using a transient-based numerical approach, solving energy balance equations for different systems. Various performance factors such as energy saving, solar fractions, and environmental impacts of auxiliary energy supplies are evaluated to feasibly assess the use of nanofluids in such devices. Simulation results demonstrate that the use of nanofluids increases the solar heater performance which reduces considerably the payback period ( P P ) of the investment in solar heating systems up to 3.34 years in Tunisian climate. Under Quebec’s climate region, the annualized solar return of the ETC system increases from 4874.65 US$ to 9785.93 US$ by adding 0.06 v% Al2O3 in water. Also, the use of nanofluids in solar collectors with electric auxiliary heaters reduces harmful CO2 emissions up to 0.49 tons/year.

STUDY THE FEASIBILITY OF USING SOLAR ENERGY AND RATIONALIZING THE USE OF ELECTRIC ENERGY TO REDUCE THE SHORTAGE IN ENERGY SUPPLY IN IRAQ

The increase of energy consumption of fossil fuel as a result of the increase in the population of Iraq, the development of urban lifestyle, the increase in the number of vehicles as well as the increase of power generators has led to dangerous environmental risks, air, water and soil pollution, the spread of cancers and sensitivity diseases besides the reduction of the Iraqi exports of raw oil as a result of domestic consumption. Therefore; searching for solutions to restricting or surmounting these effects such as finding clean renewable sources of power have become inevitable. Among those renewable sources which are environmentally friendly and of middle cost is the solar power that includes solar heater and solar cells boards. Using 100.000 solar heaters saves (324.800 Megawatt hour) within one year, while using 100.000 solar cells system with an energy of (1000 watt) saves (438.000 Megawatt hour) within one year. Other means of reducing the effects of using fossil fuel is spreading the culture of power rationing and avoiding the waste and excessive consumption through cooperation with educational institutions by setting special programs such as courses, symposiums, posters and setting out a day for power consumption rationing. Turning off 10% of sets operation time in 1.000.000 house would save more than (2.076.120 megawatt hour) per annum.