The Effect of Hydrogen as a Coolant on the Characteristics of Humidification-Dehumidification Desalination Systems

The air humidification-dehumidification (HDH) technique for water desalination can be useful in many water production applications. Researchers from all around the world have examined various implementations of this technology to improve it. The present research investigates the effect of three dehumidifier coolants on the system. These coolants include water, helium, and hydrogen. The impact of these coolants on the parameters of the humidification-dehumidification desalination system will be discussed. The investigation’s parameters are tested at various mass ratios, air flow rates, and air outlet heaters. The results show that when hydrogen is employed as a dehumidifier coolant, the gained output ratio (GOR) achieves its peak of 6.37 in the considered mass ratio range of 2.1 to 3. On the other hand, when hydrogen is utilized as a dehumidifier coolant, the system produces the maximum entropy, with the dehumidifier contributing the most. When the mass ratio changes from 2 to 3, the average entropy generation for the system using hydrogen in the dehumidifier increases by 3.8 and 2.9 times, respectively, compared to the average entropy generation for the system using water and helium. However, when hydrogen is used as a dehumidifier coolant, safety concerns must be addressed, as well as the size and cost of heat exchangers in comparison to water

Performance Investigation of Evacuated Tube Collector using Different Nano fluids Applied to Winter Climatic Conditions in Egypt

In this paper, the performance of the evacuated tube solar collector is investigated theoretically by the TRNSYS program. The simulation is conducted during the winter of 14th February-2019 in Cairo – Egypt. In this simulation, water and Nanofluids areworking fluids. The types of Nanofluids are CeO2/water, WO3/water and AL2O3/water. The simulation is conducted at0.015%,0.025%, 0.035% and 0.045% (volume concentrations).The mass flux rate and tilt angle are 0.017 kg/s.m2and 45o; respectively.The results show that the collector has the highest performance using nanofluids at studied concentrations. At 12:00 PM, thehighest useful energy gain can be obtained from CeO2/water Nanofluid at 0.045% concentration, while thermal efficiency ishigher by 34.2% than water. The nanofluidWO3/water presents low performance than that of CeO2/water and AL2O3/water. The thermal efficiencies ofAL2O3/ water and WO3/ water Nanofluids are higher than water by 28.4% and 12.5%; respectively, atconcentration of 0.045% and 12:00P