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

2021 ◽  
Vol 13 (23) ◽  
pp. 13491
Author(s):  
Sadam Hussain Soomro ◽  
Ravichandran Santosh ◽  
Chul-U Bak ◽  
Woo-Seung Kim ◽  
Young-Deuk Kim
Keyword(s):  
Thermal Energy ◽  
Mass Conservation ◽  
Weather Data ◽  
Humid Climate ◽  
Jeddah City ◽  
Output Ratio ◽  
Improved Performance ◽  
Solar Heater ◽  
Flat Plate Collector ◽  
Environmentally Friendly Approach

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.

Performance Evaluation and Characterization of a Direct Absorption Solar Humidifier for Humidification–Dehumidification Desalination

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Tapan Dave ◽  
Shankar Krishnan
Keyword(s):  
Thermal Energy ◽  
Solar Thermal ◽  
Present System ◽  
Solar Thermal Energy ◽  
Efficiency Curve ◽  
Local Flow ◽  
Collector Efficiency ◽  
Solar Heater ◽  
Normalized Gain

Abstract In the present work, a solar humidifier suitable for solar thermal energy-driven humidification–dehumidification desalination has been proposed and experimentally investigated. The proposed solar humidifier compacts the solar heater and humidifier into a single component while reducing energy costs by utilizing solar thermal energy. Several local flow storage and distributor elements are created in the absorber surface that produces a “dam effect” in combination with stainless steel mesh and airflow baffles. The effect of varying flowrates of air and water, inlet water temperature as well as inlet relative humidity on the performance of the solar humidifier is investigated. Humidity based normalized gain (NGhumidity) versus solar humidifier efficiency curve, which depicts a heat and mass performance of the solar humidifier, is reported. This curve is analogous to the normalized gain versus collector efficiency curve of the solar water/air heater. The productivity of the present system is compared with the published results of similar studies. Best mean productivity of 838.5 g/m2/h and best instantaneous productivity of 955.2 g/m2/h were achieved using a present solar humidifier, showcasing the effectiveness of the proposed approach. The comparison of the performance of the solar humidifier with the performance of conventional configuration having separate heating and humidification is also carried out. It was found that the investigated solar humidifier (internal heating configuration) does perform the same in terms of utilization of solar energy for evaporation, if not better, than the conventional separate humidifier and heater (external heating configuration).

scholarly journals EXPERIMENTAL INVESTIGATION ON DRYING OF BLANCHED BITTER GOURD SLICES IN A TRIPLE PASS SOLAR DRYER

2017 ◽  
Vol 13 (7) ◽  
pp. 6369-6375
Author(s):  
S. Kesavan ◽  
T.V. Arjunan ◽  
S. Vijayan
Keyword(s):  
Energy Storage ◽  
Flat Plate ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Thermal Storage ◽  
Bitter Gourd ◽  
Storage Medium ◽  
Sun Drying ◽  
Solar Dryer ◽  
Flat Plate Collector

This paper involves with the experimental performance study of a triple pass solar flat plate collector integrated with  thermal energy storage medium for drying of blanched bitter gourd slices. The experimental setup consists of a blower, triple pass flat plate collector and a drying chamber. The experimets were carried out in the meterological conditions of Coimbatore, Tamil Nadu, India. The mass flow rate of air through the system was set as 0.06 kgs-1. From the results, it could be comprehended that, (i) triple pass arrangement of air improves the performance of flat plate collector (ii) thermal energy storage medium played an important role in consistent outlet air temperature and the thermal efficiency (iii) triple pass solar dryer took 5 hours to reach the final moisture content of bitter gourd (9% on wet basis) which is 29 % and 37.5% faster than without thermal storage and open sun drying system. It could be concluded that triple pass solar air collector performs better than without thermal storage and open sun drying.

scholarly journals Transient Behavior Analysis for Solar Energy Storage in PCM-CFM Material Using Equivalent Heat Capacity Method as Storage Model

2019 ◽  
Vol 14 (2) ◽  
pp. 40-57
Author(s):  
Talib K. Murtadha ◽  
Hussien M M. S Salih ◽  
Ali D. Salman
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Storage ◽  
Experimental Results ◽  
Paraffin Wax ◽  
Storage Material ◽  
Copper Foam ◽  
Thermal Energy Storage Material ◽  
Flat Plate Collector

A paraffin wax and copper foam matrix were used as a thermal energy storage material in the double passes air solar chimney (SC) collector to get ventilation effect through daytime and after sunset. Air SC collector was installed in the south wall of an insulated test room and tested with different working angles (30o, 45o and 60o). Different SC types were used; single pass, double passes flat plate collector and double pass thermal energy storage box collector (TESB). A computational model based on the finite volume method for transient tw dimensional domains was carried out to describe the heat transfer and storage in the thermal energy storage material of collector. Also, equivalent specific heat method was employed to describe the heat storage and release in the mushy zone. Experimental results referred to an increase in thermal conductivity of paraffin wax that supported by copper foam matrix more than ten times. While the ventilation effect was still active for hours after the sun set, depending on the heat storage amount. Maximum ventilation mass flow rate with TESB collector was recorded with value equals to 36.651 kg/hr., when the overall discharge coefficient that was calculated for the system equals to 0.371. Experimental results showed that the best working angle range was 45~60o, and the highest air to the collector approaching temperature appeared to the double passes flat plate collector. Results gave greater heat storage efficiency of (47)% when the maximum solar radiation was 780 W/m2 at 12.00pm, while the energy summation through duration charge time was 18460 kJ. Computational results, depending on the equivalent heat capacity method for heat storage or release from phase change material that supported by copper foam matrix, showed the behavior of paraffin wax melting and solidification situation through periodic for charge and released heat from the solar collector. Also, these results gave agreement approaching the experimental results for the heat storage in the combined heat storage material, with standard error of 16.8%.

scholarly journals Effect of thermal energy storage in energy consumption required for air conditioning system in office building under the African Mediterranean climate

2014 ◽  
Vol 18 (suppl.1) ◽  
pp. 201-212 ◽  
Author(s):  
Mohamed Abdulgalil ◽  
Franc Kosi ◽  
Mohamed Musbah ◽  
Mirko Komatina
Keyword(s):  
Heat Transfer ◽  
Energy Consumption ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Air Conditioning ◽  
Office Building ◽  
Weather Data ◽  
Time Shift ◽  
Partial Load

In the African Mediterranean countries, cooling demand constitutes a large proportion of total electrical demand for office buildings during peak hours. The thermal energy storage systems can be an alternative method to be utilized to reduce and time shift the electrical load of air conditioning from on-peak to off-peak hours. In this study, the Hourly Analysis Program has been used to estimate the cooling load profile for an office building based in Tripoli weather data conditions. Preliminary study was performed in order to define the most suitable operating strategies of ice thermal storage, including partial (load leveling and demand limiting), full storage and conventional A/C system. Then, the mathematical model of heat transfer for external ice storage would be based on the operating strategy which achieves the lowest energy consumption. Results indicate that the largest rate of energy consumption occurs when the conventional system is applied to the building, while the lowest rate of energy consumption is obtained when the partial storage (demand limiting 60%) is applied. Analysis of results shows that the new layer of ice formed on the surface of the existing ice lead to an increase of thermal resistance of heat transfer, which in return decreased cooling capacity.

Comparison of methodologies for generation of future weather data for building thermal energy simulation

2020 ◽  
Vol 206 ◽  
pp. 109556 ◽  
Author(s):  
João Bravo Dias ◽  
Guilherme Carrilho da Graça ◽  
Pedro M.M. Soares
Keyword(s):  
Thermal Energy ◽  
Energy Simulation ◽  
Weather Data

scholarly journals Effects of Pressure-Induced Density Changes in the Thermal Energy Absorbed by a Micro-Encapsulated Phase-Change Material

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1254 ◽  
Author(s):  
Ernesto Hernández-Cooper ◽  
José Otero
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Mass Conservation ◽  
Melting Process ◽  
Thermal Balance ◽  
Rate Of Change ◽  
Storage Unit ◽  
Proposed Model ◽  
Change Material

Density changes produced by pressure increments during melting of a spherically confined phase-change material have an impact on the thermal energy absorbed by the heat storage unit. Several authors have assumed incompressible phases to estimate the volume change of the phase-change material and the thermal balance at the liquid–solid interface. This assumption simplifies the problem but neglects the contribution of density changes to the thermal energy absorbed. In this work, a thermal balance at the interface that depends on the rate of change of the densities and on the shape of the container is found by imposing total mass conservation. The rigidity of the container is tuned through the coupling constant of an array of springs surrounding the phase-change material. This way, the behavior of the system can be probed from the isobaric to the isochoric regimes. The sensible and latent heat absorbed during the melting process are obtained by solving the proposed model through numerical and semi-analytical methods. Comparing the predictions obtained through our model, it is found that even for moderate pressures, the absorbed thermal energy predicted by other authors can be significantly overestimated.

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