scholarly journals Development of Small-scale Two-stage Photovoltaic-photothermal Humidification-dehumidification Desalination System

2018 ◽  
Vol 7 (2) ◽  
pp. 90
Author(s):  
Junquan Zhang ◽  
Ke Yang ◽  
Changsheng Peng
Keyword(s):  
Solar Radiation ◽  
Ambient Temperature ◽  
Water Temperature ◽  
Air Temperature ◽  
Flow Rate ◽  
Sea Water ◽  
Small Scale ◽  
Water Production ◽  
Two Stage ◽  
Solar Radiation Intensity

Air bubble has been proved that it can increase evaporation area and coefficient of mass transfer and heat transfer. Two-stage evaporation system can indirectly increase the contact area of water and vapor, reduce the volume of single evaporation system, and can also combine the multiple systems flexibly. So a new type of small scale two-stage photovoltaic-photothermal humidification-dehumidification (HDH) desalination system is designed, and the relationship between solar radiation and temperature is measured, and the water production capability of the system is investigated. The effect of water temperature, ambient temperature, air flow rate and air temperature on desalination performance is also investigated. The results showed that the rate of water production is positively correlated with sea water temperature, ambient temperature, gas flow rate and air temperature. And the gas temperature is positively correlated with the solar radiation intensity. When the ambient temperature is higher than 25 ℃, the cumulative amount of irradiation is 22.3 MJ/m2, the cumulative water production is 19.2 L/d, and 6.4 L/( m2∙d), the thermal efficiency is 0.66. The cost of water produced through the designed HDH system is 0.08 $/L.

scholarly journals Integration of a Solar Parabolic Dish Collector with a Small-Scale Multi-Stage Flash Desalination Unit: Experimental Evaluation, Exergy and Economic Analyses

2021 ◽  
Vol 13 (20) ◽  
pp. 11295
Author(s):  
Ali Babaeebazaz ◽  
Shiva Gorjian ◽  
Majid Amidpour
Keyword(s):  
Solar Radiation ◽  
Flow Rate ◽  
Quality Parameters ◽  
Small Scale ◽  
Conical Cavity ◽  
Multi Stage ◽  
Circulation Circuit ◽  
Parabolic Dish ◽  
Economic Analyses ◽  
The Cost

In this study, a small-scale two-stage multi-stage flash (MSF) desalination unit equipped with a vacuum pump and a solar parabolic collector (PDC) with a conical cavity receiver were integrated. To eliminate the need for heat exchangers, a water circulation circuit was designed in a way that the saline feedwater could directly flow through the receiver of the PDC. The system’s performance was examined during six days in July 2020, from 10:00 a.m. to 3:00 p.m., under two distinct scenarios of the MSF desalination operation under the vacuum (−10 kPa) and atmospheric pressure by considering three saline feedwater water flow rates of 0.7, 1 and 1.3 L/min. Furthermore, the performance of the solar PDC-MSF desalination plant was evaluated by conducting energy and exergy analyses. The results indicated that the intensity of solar radiation, which directly affects the top brine temperature (TBT), and the values of the saline feedwater flow rate have the most impact on productivity. The maximum productivity of 3.22 L per 5 h in a day was obtained when the temperature and saline feedwater flow rate were 94.25 °C (at the maximum solar radiation of 1015.3 W/m2) and 0.7 L/min, respectively, and the MSF was under vacuum pressure. Additionally, it was found that increasing the feedwater flow rate from 0.7 to 1.3 L/min reduces distillate production by 76.4% while applying the vacuum improves the productivity by about 34% at feedwater flow rate of 0.7 L/min. The exergy efficiency of the MSF unit was obtained as 0.07% with the highest share of exergy destruction in stages. The quality parameters of the produced distillate including pH, TDS, EC and DO were measured, ensuring they lie within the standard range for drinking water. Moreover, the cost of freshwater produced by the MSF plant varied from 37 US$/m3 to 1.5 US$/m3 when the treatment capacity increased to 8000 L/day.

Experimental and Numerical Study of Water Distillation Performance of Small-Scale Direct Contact Membrane Distillation System

2017 ◽  
Author(s):  
Danielle Park ◽  
Elnaz Norouzi ◽  
Chanwoo Park
Keyword(s):  
Water Temperature ◽  
Direct Contact ◽  
Membrane Distillation ◽  
Small Scale ◽  
Feed Water ◽  
Water Production ◽  
Water Distillation ◽  
Direct Contact Membrane Distillation ◽  
Feed Temperature ◽  
Feed Water Temperature

A small-scale Direct Contact Membrane Distillation (DCMD) system was built to investigate its water distillation performance for varying inlet temperatures and flow rates of feed and permeate streams, and salinity. A counterflow configuration between the feed and permeate streams was used to achieve an efficient heat exchange. A two-dimensional Computational Fluid Dynamics (CFD) model was developed and validated using the experimental results. The numerical results were compared with the experiments and found to be in good agreement. From this study, the most desirable conditions for distilled water production were found to be a higher feed water temperature, lower permeate temperature, higher flow rate and less salinity. The feed water temperature had a greater impact on the water production than the permeate water temperature. The numerical simulation showed that the water mass flux was maximum at the inlet of the feed stream where the feed temperature was the highest and rapidly decreased as the feed temperature decreased.

Flow Control and Unsteady State Analysis on Thermal Performance of Solar Air Collectors

Solar Energy ◽  
2003 ◽  
Author(s):  
Sadasuke Ito ◽  
Minoru Kashima ◽  
Naokatsu Miura
Keyword(s):  
Control System ◽  
Flow Control ◽  
Air Temperature ◽  
Flow Rate ◽  
Thermal Performance ◽  
Unsteady State ◽  
Solar Radiation Intensity ◽  
Flat Plate Collector ◽  
Unsteady State Analysis ◽  
State Analysis

Solar air collectors can be used for heating rooms, drying crops and wood, and heating water. In present studies, first, a flow control system for obtaining a constant temperature at the exit of a flat-plate collector was installed in a hot air supply system and the feasibility of the control system was examined. When the flow temperature was lower than the temperature that was set by a digital indicating controller, the fan power was reduced to decrease the flow rate. When the outlet air temperature was higher than the setting temperature, the flow rate was increased. Consequently, the control system worked well to maintain the exit air temperature. Secondly, an unsteady state analysis was made on thermal performance of the collector. In analysis, flow rate variations over time were given as conditions. Validity of this analysis was checked by experimentation. Analytical results agreed well even when solar radiation intensity, wind speed, or flow rate changed abruptly.

scholarly journals Numerical Performance Investigation of Hybrid PV/Thermal System

2018 ◽  
Vol 7 (4.19) ◽  
pp. 818
Author(s):  
Kadhim K. Idan Al-Chlaihawi ◽  
Dhafer A. Hamzah ◽  
Ahmed K. Zarzoor ◽  
Yousif M. Hasan
Keyword(s):  
Solar Radiation ◽  
Water Temperature ◽  
Flow Rate ◽  
Cooling Water ◽  
Electrical Performance ◽  
Flow Rates ◽  
Electrical Efficiency ◽  
Cooling Water Temperature ◽  
Present Work Deal ◽  
Numerical Performance

Promoting reduction of PV temperature plays crucial role in increasing electrical performance. The present work deal with different types of absorber shape for analysing heat transfer phenomena. Serpentine and spiral absorber are using to verify this purpose with different boundary conditions of inlet mass flow rate and inlet temperatures.The recent study was conducted to evaluate the effect of some operating and designing parameters such as solar radiation levels, flow rates, absorber shape and cooling water temperature on the performance of PVT system numerically. Performance of PVT system determined by thermal efficiency, electrical efficiency and the summation of both known as total or PVT efficiency. Solar radiation ranging from 500 W/m2 to1000 W/m2 was introduced and at each, flow rates of water ranging from 0.016 kg/s to 0.05 kg/s. The results show that the performance of PVT increases with a flow rate at all radiation levels. Also the spiral flow absorber gives a higher performance than serpentine absorber where the value of  of spiral absorber is increased by about 5.2% compared to the value of serpentine absorber, on the other hand, the rate of heat loss ( decreased by about 10%.Increasing initial cooling water temperature degrades electrical efficiency of PVT system.  

scholarly journals An experimental investigation on the coefficient of performance of the small hot water heat pump using refrigeration R410A and R32

2020 ◽  
Vol 3 (2) ◽  
pp. First
Author(s):  
Le Minh Nhut ◽  
Tran Quang Danh
Keyword(s):  
Ambient Temperature ◽  
Water Temperature ◽  
Water Flow ◽  
Heat Pump ◽  
Flow Rate ◽  
Water Flow Rate ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Electric Heater ◽  
Initial Water

Hot water is an important factor in domestic life and industrial development. Today, the heat pump is used to produce hot water more and more popular because it has many advantages of saving energy compared to the method of producing hot water by the hot water electric heater. The main aim of this study is to evaluate of the coefficient of performance (COP) of the small hot water heat pump using refrigeration R410A and R32. The capacity of both hot water heat pump is similar, one using new refrigerant R32 and other using refrigerant R410A. These heat pumps were designed and installed at the Ho Chi Minh City University of Technology and Education to evaluate the COP for the purpose of application the new refrigerant R32 for hot water heat pump. The compressor capacity is 1 Hp, the volume of hot water storage tank is of 100 liters and is insulated with thickness of 30 mm to reduce the heat loss to invironment, the required hot water temperature at the outlet of condenser is 50 oC, and the amount of required hot water is 75 liters per batch and is controlled by float valve. The experimental results indicate that the COP of the heat pump using the new refrigerant R32 is higher than heat pump using refrigerant R410A from 9% to 15% when the experimental conditions such as ambient temperature, initial water flow rate through the condenser and the required temperature of hot water were the same. In addition, the effect of the ambient temperature, initial water temperature and water flow rate were also evaluated.

scholarly journals Determination of physical characteristics of horizontally positioned solar module in real climate conditions in Nis, Serbia

2016 ◽  
Vol 14 (1) ◽  
pp. 37-51 ◽  
Author(s):  
Lana Pantic ◽  
Tomislav Pavlovic
Keyword(s):  
Solar Radiation ◽  
Ambient Temperature ◽  
Output Power ◽  
Radiation Intensity ◽  
Negative Impact ◽  
Open Circuit ◽  
Physical Characteristics ◽  
Solar Module ◽  
Climate Conditions ◽  
Solar Radiation Intensity

The aim of this paper was to investigate the influence of solar radiation intensity, ambient temperature, wind speed and solar module temperature on the modules physical characteristics, in local climate conditions and for all seasons in Nis, Serbia. Twelve sunny days, for each month of the year, from the period September 2014 - June 2016 were selected. During each day meteorological parameters, solar module temperature and solar module output parameters were measured. The highest values of solar radiation intensity, ambient temperature and solar module temperature were measured in summer months, while the lowest values were in winter months. The maximal values of the output power were measured in summer months due to the high values of solar radiation intensity on the solar modules surface. A negative impact of high solar module temperature on the open circuit voltage, the output power, the fill factor and the efficiency was observed. In the winter months the local climatic conditions and air pollution have an adverse impact on the solar module efficiency and lead to a noticeable reduction of the efficiency.

Effects of solar radiation on thermal sensation and physical fatigue of the human body under heavy-load exercise

2020 ◽  
pp. 1420326X2097473
Author(s):  
Yongqiang Xiao ◽  
Yaping Gao ◽  
Yi Wang ◽  
Xiaojing Meng
Keyword(s):  
Blood Pressure ◽  
Solar Radiation ◽  
Ambient Temperature ◽  
Human Body ◽  
Field Experiments ◽  
Physiological Stress ◽  
Thermal Sensation ◽  
Heavy Load ◽  
Solar Radiation Intensity ◽  
Significant Difference

Solar radiation intensity affects both subjective reactions and physiological functions, especially for people who exercise heavily. Field experiments including a questionnaire survey at various ambient temperatures were performed; outdoor activities under shading (irradiance I =  50 ± 20 W/m2) and non-shading ( I =  700 ± 50 W/m2) conditions during summer in Xi'an were recorded. The results of questionnaires indicated that when the human body reached an extremely hot state, the corresponding environmental temperature was 3.7 °C lower under the non-shading condition, and the range of actual acceptable temperatures was narrower. In terms of thermal sensation, there was a significant difference for people who exercise heavily and those who do not. The results also showed that the curve of fatigue sensation exhibited an inverse Gaussian distribution. Namely, fatigue was promoted under both colder and hotter conditions. Moreover, under non-shading condition, the lowest fatigue incidence was higher, and the corresponding ambient temperature was lower. Changes in objective physiological responses indicated that the solar radiation might cause heat stress. Therefore, when the ambient temperature was higher than 32 °C, physiological stress was higher. Under the same exercise load, the blood pressure was higher under the non-shading condition and systolic blood pressure increased with ambient temperature.

Characteristics of Jointed Plain Concrete Pavement (JPCP) Built-in Temperature in Different Climate Conditions

2013 ◽  
Vol 723 ◽  
pp. 960-967
Author(s):  
Chang Bin Hu ◽  
Zeng Hua Sun ◽  
Li Juan Wang
Keyword(s):  
Numerical Simulation ◽  
Solar Radiation ◽  
Air Temperature ◽  
Temperature Difference ◽  
Plain Concrete ◽  
Concrete Pavement ◽  
Early Age ◽  
Climate Conditions ◽  
Solar Radiation Intensity ◽  
Basic Temperature

To understand the characteristics of early-age built-in temperature in JPCP, the actual data of construction climate conditions of typical regions in China were investigated. Based on the application of early-age JPCP temperature numerical simulation program, built-in temperature characteristics of early-age pavement in typical regions was analyzed. The results show that the pavement constructed in different climate conditions produce difference characteristics of early-age built-in temperature due to geographical distinction. Positive built-in temperature difference of JPCP is larger in the regions which have difference in temperature between day and night or higher solar radiation intensity, while the negative built-in temperature difference isn’t influenced obviously by different regions and paving conditions. The maximum positive (negative) built-in temperature difference generally appears in pavement constructed in hot summer. The air temperature is the major factor affecting built-in basic temperature. The higher air temperature, results in the higher built-in basic temperature (temperature in slab bottom) is.

scholarly journals Efficiency of solar radiation conversion in photovoltaic panels

2018 ◽  
Vol 10 ◽  
pp. 02014 ◽  
Author(s):  
Sławomir Kurpaska ◽  
Jarosław Knaga ◽  
Hubert Latała ◽  
Jakub Sikora ◽  
Wiesław Tomczyk
Keyword(s):  
Solar Radiation ◽  
Ambient Temperature ◽  
Conversion Efficiency ◽  
Radiation Intensity ◽  
Radiation Energy ◽  
Climatic Conditions ◽  
Ambient Conditions ◽  
Photovoltaic Panels ◽  
Solar Radiation Intensity ◽  
Radiation Conversion

This paper included analysis the conversion efficiency in photovoltaic panels. The tests were done between February and June at a test stand equipped with three commonly used types of photovoltaic panels: poly- and monocrystalline silicon and with semi-conductive layer made of copper (Cu), indium (In), gallium (Ga) and selenium (Se) (CIGS). Five days of each month were selected for a detailed analysis. They were close to the so-called recommended day for calculations in solar power engineering. Efficiency, calculated as the yield of electrical energy in relation to solar radiation energy reaching the panels was made conditional upon solar radiation intensity and ambient temperature. It was found that as solar radiation intensity and ambient temperature increase, the efficiency of solar radiation conversion into electricity is reduced. Correlation dependence was determined for the test data obtained, describing temperature change of panels depending on climatic conditions. It was found that as panel temperature increases, the conversion efficiency is reduced. Within the tested scope of experiment conditions, the efficiency was reduced in the range between 20.1 and 22.8%. The authors also determined the average efficiency values in individual test months together with average ambient conditions of the environment where the process of solar radiation conversion took place.

Sign in / Sign up

Export Citation Format

Share Document