Numerical Simulation of the Performance of a Salt-Gradient Solar Pond

1983 ◽  
Vol 105 (4) ◽  
pp. 369-374 ◽  
Author(s):  
Z. Panahi ◽  
J. C. Batty ◽  
J. P. Riley
Keyword(s):  
Dynamic Performance ◽  
Convective Zone ◽  
Net Energy ◽  
Storage Efficiency ◽  
One Dimensional ◽  
Solar Pond ◽  
Optimization Study ◽  
Storage Zone ◽  
Salt Gradient ◽  
Convective Layer

A one-dimensional mathematical model which simulates the dynamic performance of stratified solar brine ponds is described. The model simulates the upper convective zone, the middle nonconvective zone, and the lower convective zone. In addition to the energy flux, the model simulates the varying brine densities as a function of temperature and salt concentration, and thus is able to examine various pond stability criteria. On the basis of model operational studies, the following results are presented: (i) a study of overall pond efficiency in terms of the upper convective layer; (ii) an optimization study of the thickness of the nonconvective zone in terms of net energy transmission to the lower convective zone; (iii) an investigation of the heat storage efficiency and of the overall pond efficiency as a function of pond loading rate for a particular depth of storage zone.

Assessing the Maximum Stability of the Nonconvective Zone in a Salinity-Gradient Solar Pond

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
A. A. Abdullah ◽  
K. A. Lindsay
Keyword(s):  
Salinity Gradient ◽  
Fluid Velocity ◽  
Weather Conditions ◽  
Convective Zone ◽  
Heat Extraction ◽  
Solar Pond ◽  
Maximum Stability ◽  
Storage Zone ◽  
The Stability

The quality of the stability of the nonconvective zone of a salinity-gradient solar pond (SGSP) is investigated for an operating protocol in which the flushing procedure exactly compensates for evaporation losses from the solar pond and its associated evaporation pond. The mathematical model of the pond uses simplified, but accurate, constitutive expressions for the physical properties of aqueous sodium chloride. Also, realistic boundary conditions are used for the behaviors of the upper and lower convective zones (LCZs). The performance of a salinity-gradient solar pond is investigated in the context of the weather conditions at Makkah, Saudi Arabia, for several thickness of upper convective zone (UCZ) and operating temperature of the storage zone. Spectral collocation based on Chebyshev polynomials is used to assess the quality of the stability of the pond throughout the year in terms of the time scale for the restoration of disturbances in temperature, salinity, and fluid velocity underlying the critical eigenstate. The critical eigenvalue is found to be real and negative at all times of year indicating that the steady-state configuration of the pond is always stable, and suggesting that stationary instability would be the anticipated mechanism of instability. Annual profiles of surface temperature, salinity, and heat extraction are constructed for various combinations for the thickness of the upper convective zone and storage zone temperature.

Study on the Salt Gradient Maintenance of Solar Pond

2014 ◽  
Vol 926-930 ◽  
pp. 4373-4376
Author(s):  
Chun Juan Gao ◽  
Qi Zhang ◽  
Liang Wang ◽  
Yan An Zhang ◽  
Xi Ping Huang
Keyword(s):  
Convective Zone ◽  
Salinity Variation ◽  
Research Results ◽  
Solar Pond ◽  
Long Time ◽  
Salt Gradient ◽  
Series Of Experiments

In this paper, we established a simulated mini solar pond, and carried out a series of experiments to maintain the salt gradient solar pond. Meanwhile, the salinity variation of the lower convective zone (LCZ) of solar pond was investigated. Research results showed that by means of injecting saturated brine into the bottom of solar pond periodically, the salt gradients of solar pond could maintain relatively stable during a long time.

Study of Establishment and Operation of Salt-Gradient Solar Pond

2014 ◽  
Vol 472 ◽  
pp. 409-412
Author(s):  
Chun Juan Gao ◽  
Qi Zhang ◽  
Ze Liang Dong ◽  
Shu Yuan Guo ◽  
Xi Ping Huang
Keyword(s):  
Experimental Investigation ◽  
Solar Energy ◽  
Convective Zone ◽  
Saline Injection ◽  
Salty Water ◽  
Long Period ◽  
Gradient Layer ◽  
Solar Pond ◽  
Injection Parameters ◽  
Salt Gradient

In this paper, it was presented that the establishment and experimental investigation of a salt-gradient solar pond. The solar pond was filled with salty water to form three zones (e.g., upper convective zone, non-convective zone and lower convective zone) accordingly with different methods of saline injection. Parameters like salinity and temperature were measured and recorded daily at various locations in the salt-gradient solar pond. The results showed that solar pond collected and stored solar energy for a long period of time can be possible by controlling the thickness and salinity of salt gradient layer of the solar pond.

scholarly journals Modeling of the Surface Convective Layer of Salt-Gradient Solar Ponds

1982 ◽  
Vol 104 (4) ◽  
pp. 293-298 ◽  
Author(s):  
Y. S. Cha ◽  
W. T. Sha ◽  
W. W. Schertz
Keyword(s):  
Double Diffusive Convection ◽  
Vertical Temperature ◽  
Solar Ponds ◽  
One Dimensional ◽  
Diffusive Convection ◽  
Combined Action ◽  
Salt Gradient ◽  
Wind Mixing ◽  
Convective Layer ◽  
Double Diffusive

A one-dimensional numerical model is developed to predict the diurnal variations of vertical temperature and concentration profiles in salt-gradient solar ponds. The model employs augmented thermal and mass diffusivities due to turbulent wind mixing and double-diffusive convection. Numerical results indicate that the thickness of the surface convective layer increases with wind speed (or the wavelength of the surface wave). Double-diffusive convection is, in the absence of wind, capable of sustaining a mixed layer at the surface when strong cooling occurs over the pond. In field ponds, the surface convective layer is probably maintained as a result of the combined action of wind-generated turbulent mixing and double-diffusive convection.

The Influence of Height of LCZ on the Salinity Diffusion of Solar Pond

2013 ◽  
Vol 448-453 ◽  
pp. 1521-1524
Author(s):  
Chun Juan Gao ◽  
Qi Zhang ◽  
Hai Hong Wu ◽  
Liang Wang ◽  
Xi Ping Huang
Keyword(s):  
Solar Energy ◽  
Fresh Water ◽  
Salt Water ◽  
Salinity Gradient ◽  
Good Method ◽  
Convective Zone ◽  
Solar Ponds ◽  
Solar Pond ◽  
Salt Gradient ◽  
And Diffusion

The solar ponds with a surface of 0.3m2were filled with different concentration salt water and fresh water. The three layer’s structure of solar ponds was formed in the laboratory ponds by using the salinity redistribution. The performance and diffusion of salinity were xperimentally in the solar pond. The measurements were taken and recorded daily at various locations in the salt-gradient solar pond during a period of 30 days of experimentation. The experimental results showed that the salinity gradient layer can sustain a longer time when the lower convective zone is thicker, which is benefit to store solar energy. Therefore, properly increasing the height of LCZ is a good method to enhance the solar pond performance.

scholarly journals Investigation of saturation temperature in solar pond for different sizes

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2905-2914 ◽  
Author(s):  
Haci Sogukpinar ◽  
Ismail Bozkurt
Keyword(s):  
Saturation Temperature ◽  
Side Wall ◽  
Equilibrium Temperature ◽  
Convective Zone ◽  
Discrete Ordinates ◽  
Solar Ponds ◽  
Solar Pond ◽  
Storage Zone ◽  
Zone Depth ◽  
Depth Ranges

This paper deals with the modelling of solar ponds for different sizes to calculate saturation time and temperature by using discrete ordinates method. The modeled solar pond is a subsoil type and aimed to minimize the heat losses by isolating side wall and ground with foam with the thickness of 10 cm in all cases. In the model, upper convective zone is 10 cm deep and non-convective zone consists of five layer and each layer is 10 cm deep and storage zone depth ranges from 40-400 cm. Therefore, the solar pond totally consists of seven layers. The saturation temperature was found to be about 322 K for 12 different solar pond. For a depth of 40 cm, the equilibrium temperature was reached in 1000 hours, 1300 hours for 60 cm, 1400 hours for 80 cm, 1500 hours for 100 cm, 1600 hours for 120 cm, 1750 hours for 1140 cm, 1800 hours for 180 cm, 2700 hours for 200 cm, 1800 hours for 250 cm, 3400 hours for 300 cm, and 6000 hours have passed for 400 cm. As the depth increases, time to reach to the equilibrium temperature increases but increment amount of water and time to reach equilibrium temperature shows a proportional increase. At the same time we calculated that, when we increase the width of the pond by keeping the depth constant, the saturation temperature and the time did not changed for the seven different cases.

Construction and Startup Performance of the Miamisburg Salt-Gradient Solar Pond

1981 ◽  
Vol 103 (1) ◽  
pp. 11-16 ◽  
Author(s):  
L. J. Wittenberg ◽  
M. J. Harris
Keyword(s):  
Storage Temperature ◽  
Water Clarity ◽  
Pond Water ◽  
Convective Zone ◽  
Fuel Oil ◽  
Gradient Zone ◽  
Solar Pond ◽  
Salt Gradient ◽  
Startup Performance ◽  
The Cost

The largest salt-gradient solar pond in the U. S. occupies an area of 2020 m2 and was installed for only $35/m2. The pond has a storage layer of 1.6 m consisting of 18 percent sodium chloride, a l-m gradient zone and a 0.4-m top convective zone. After 1.5 yr of operation, the storage temperature reached a maximum of 64°C in July and a minimum of 28°C in February. During July-September 1979, 143.5 GJ (136 million Btu) of heat was utilized. Under steady-state conditions, the pond is conservatively predicted to deliver over 1015 GJ/yr (962 million Btu) of heat to be used principally for heating an outdoor swimming pool in the summer and an adjacent recreation building from October to December each year. Based upon a 15-yr depreciation of the installation costs, the cost of this heat, $8.95/GJ ($9.45/million Btu) is already below the cost of heating with fuel oil. Maintenance of water clarity, corrosion of metallic components, and the assurance of the containment of the pond water have been the principal operational concerns and will require further study.

Experimental Study on Solar Ponds Combination with Solar Collector

2011 ◽  
Vol 347-353 ◽  
pp. 174-177 ◽  
Author(s):  
Dan Wu ◽  
Hong Sheng Liu ◽  
Wen Ce Sun
Keyword(s):  
Experimental Study ◽  
Solar Radiation ◽  
Solar Collector ◽  
Experimental Period ◽  
Convective Zone ◽  
Ambient Conditions ◽  
Solar Ponds ◽  
Ambient Temperatures ◽  
Solar Pond ◽  
Salt Gradient

The performance of Salt-gradient solar ponds (SGSP) with and without the solar collector are investigated experimentally in this paper. Two mini solar ponds with same structure are built, and one the them is appended with an exceptive solar collector for compared study. The salinity, temperature and turbidity of solar pond are studied contrastively for the two solar ponds under the same ambient conditions. The ambient temperatures,humidity and solar radiation are investigated during the experimental period. It was found that the temperature of the lower convective zone in the solar pond coupled with a solar collector increases by about 20% due to the introduce of solar collector.

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