Study of surface convective zone behavior of solar pond in laboratory

1994 ◽  
Vol 4 (1) ◽  
pp. 47-51 ◽  
Author(s):  
Renyuan Zhang ◽  
C.E. Nielsen
Keyword(s):  
2017 ◽  
Vol 139 (4) ◽  
Author(s):  
A. A. Abdullah ◽  
K. A. Lindsay

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.


2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Sunirmit Verma ◽  
Ranjan Das

A new three-zone heat extraction system and its analytical model for maximizing the thermal power output of salt gradient solar ponds against a given volume is proposed. The present study considers internal heat exchangers installed within the non-convective zone (NCZ), lower-convective zone (LCZ), and the ground below the pond. The work is validated against a simplified version of the model (eliminating ground and bottom-zone heat extractions) available in the existing literature. Contrary to the conventional practice of optimizing only the middle-zone pond thickness, here, the newly proposed expression is used to find ideal values of both the middle- and bottom-zone thicknesses of the pond along with its cross-sectional area. The present work acknowledges that although the three-zone heat extraction system is the best, yet if a choice for two-zone heat extraction is to be made between the NCZ–LCZ and ground–LCZ, then the former is a better alternative. The power output is observed to increase asymptotically with mass flow rates of the three heat exchangers. However, their values must lie much below their theoretical asymptotic limits and their selection is regulated by constructional and operational constraints. These involve a minimum pond depth to offset surface evaporation, ground seepage water loss, and constraints preventing turbulent flow in heat exchangers to reduce friction loss and pumping power. This work recommends using three heat exchangers instead of either one or two and provides cardinal guidelines to extract heat in an ideal manner for a fixed solar pond volume.


2001 ◽  
Vol 123 (3) ◽  
pp. 178-178 ◽  
Author(s):  
Huanmin Lu and ◽  
Andrew H. P. Swift

The El Paso Solar Pond, a research, development, and demonstration project operated by the University of Texas at El Paso, is a salinity-gradient solar pond with a surface area of 3,000 m2 and a depth of 3.2 m. The pond utilizes an aqueous solution of predominantly sodium chloride (NaCl). The surface convective zone, main gradient zone, and bottom convective zone are approximately 0.6 m, 1.4 m, and 1.2 m, respectively. The project, located on the property of Bruce Foods, Inc., was initiated in 1983 in cooperation with the U.S. Bureau of Reclamation. Since then, the El Paso Solar Pond has successfully developed a series of technologies for solar pond operation and maintenance, as well as demonstrated several different applications. In 1985, the El Paso Solar Pond became the first in the world to deliver industrial process heat to a commercial manufacturer; in 1986 became the first solar pond electric power generating facility in the United States; and in 1987 became the nation’s first experimental solar pond powered water desalting facility. Currently, the major research at El Paso Solar Pond is focused on desalination and brine management technologies. The long-term goal of this research is to develop a systems approach for desalination/brine management via a multiple process desalination coupled with solar ponds. This systems approach will reuse the brine concentrate rejected from desalting plants thereby negating the need for disposal (zero discharge), and provide additional pollution-free renewable energy for the desalting process.


2014 ◽  
Vol 926-930 ◽  
pp. 4373-4376
Author(s):  
Chun Juan Gao ◽  
Qi Zhang ◽  
Liang Wang ◽  
Yan An Zhang ◽  
Xi Ping Huang

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.


2014 ◽  
Vol 472 ◽  
pp. 409-412
Author(s):  
Chun Juan Gao ◽  
Qi Zhang ◽  
Ze Liang Dong ◽  
Shu Yuan Guo ◽  
Xi Ping Huang

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.


2013 ◽  
Vol 448-453 ◽  
pp. 1521-1524
Author(s):  
Chun Juan Gao ◽  
Qi Zhang ◽  
Hai Hong Wu ◽  
Liang Wang ◽  
Xi Ping Huang

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.


2014 ◽  
Vol 1 (1) ◽  
pp. 54-70
Author(s):  
Seyed Saeed Madani

By applying a model of finite differences, the thermal behavior of a large solar pond is studied in this paper. The 32-year data of sunny hour’s today-length ratio are used for the estimation of global radiation. The temperature data of a similar duration are used for evaluating the ambient temperature. The effects of the variation of different zone thicknesses on pond performance are studied. It is observed that the upper convective zone thickness should be as thin as possible, the non-convective zone might be from 1 to 2 m and the lower convective zone thickness may be designed based on the application needs. A thicker non convective zone provides more insulation against heat losses, and a thicker lower convective one supplies a higher storage capacity, though with a lower operating temperature. The heat may be extracted from the pond by either a constant or a variable loading pattern. The appropriate loading pattern can be selected based on the needs and operational temperature. The LCZ temperature of the pond, under several heat extraction patterns, is also presented for practical applications.            


2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2905-2914 ◽  
Author(s):  
Haci Sogukpinar ◽  
Ismail Bozkurt

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.


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