Performance Analyses of a Combined Auxiliary Measures SGSP - Experiment Means

2014 ◽  
Vol 1055 ◽  
pp. 188-192
Author(s):  
Hong Sheng Liu ◽  
Dan Wu ◽  
Wen Ce Sun
Keyword(s):  
Porous Medium ◽  
Temperature Distribution ◽  
Solar Collector ◽  
Heat Storage ◽  
Bottom Layer ◽  
Convective Zone ◽  
Solar Ponds ◽  
Solar Pond ◽  
Performance Analyses ◽  
Storage Ability

In this work, several methods are experimentally investigated with the aim of enhancing the thermal characters of solar pond. Which included putting porous medium to the bottom of the solar pond, combining a solar collector and building evaporation basin respectively .Two mini cylindrical solar ponds are built and the thermal performance of the solar pond is investigated by comparing the temperature distribution of the two solar ponds. The experimental results show that the utilization of the porous medium in the bottom layer might enhance the heat storage ability of the lower convective zone (LCZ); The introduction of the solar collector might advance the temperature of the LCZ greatly, which lessens the heat loss of the whole system. These methods play important roles in enhancing the thermal characters of the solar pond, which brings forward a new way for the improving of solar pond.

scholarly journals Comparative Experimental Analysis of Temperature Distribution in Mini Size Permeable and Non-Permeable Varying Salt Density Solar Pond

2021 ◽  
Vol 39 (2) ◽  
pp. 486-492
Author(s):  
Periyasamy Rangaraju ◽  
Santhia Sivakumar
Keyword(s):  
Temperature Distribution ◽  
Solar Radiation ◽  
Tamil Nadu ◽  
Heat Energy ◽  
Convective Zone ◽  
Solar Ponds ◽  
Solar Pond ◽  
Mixed Medium ◽  
The Difference ◽  
High Level

Varying salt density solar pond is a method that is best suited to absorb and store solar energy. This examination includes the test enhancement of the permeable and non-permeable sunlight-based ponds dependent on its exhibition in different conditions. This experiment was done in Salem, Tamil Nadu, India. This particular topographical area has a high level of solar radiation and is a tropical district. Readings for a period of 30 days were taken; the temperature circulation, a measure of heat energy stored and concentration of salt density was assessed. For examination, two comparable solar ponds of volume 0.02 m3 and a height of 0.32 m was built. Black granite pieces, broken glass pieces, and welding spatter were used as a permeable medium in the lower convective zone (LCZ) in one of the two solar ponds. The temperatures of the permeable solar pond and non-permeable solar pond reached the highest values of 42.3℃ and 40.6℃ respectively. The solar pond with a permeable medium demonstrated an increase of 4.18% in temperature. The difference in amounts of stored thermal energy is 4.54 kJ. From the obtained parameters, the optimization is done and the permeable medium solar pond is found to store more amount of heat energy than the non- permeable solar pond. For the optimization of the mixed medium, criterion parameter βelk has been acquired in the solar pond.

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.

scholarly journals Evaluation of Solar Ponds and Aplication Area

2018 ◽  
Vol 64 ◽  
pp. 02002
Author(s):  
Sogukpinar Haci ◽  
Bozkurt Ismail ◽  
Cag Serkan
Keyword(s):  
Solar Energy ◽  
Electricity Generation ◽  
Storage Capacity ◽  
Heat Storage ◽  
Storage Systems ◽  
Hot Water ◽  
Temperature Variations ◽  
Solar Ponds ◽  
Salty Water ◽  
Solar Pond

Solar ponds are heat storage systems where solar energy is collected and stored thermally. Solar ponds were discovered during the temperature variations in the lower regions of existing saltwater pond in the area is found to be higher than their surface. Later, it was constructed artificially and started to be used. These systems have heat storage capacity at moderate temperatures. Solar pons are used in many areas such as electricity generation, heating the environment, meeting the need of hot water, drying food and obtaining fresh water from salty water. In this study, the studies about solar ponds were summarized, the construction of solar pond was explained, and the application areas were examined.

Thermal Heat Storage Gain of Salinity Gradient Solar Pond Using Evacuated Tube Solar Collectors

2015 ◽  
Vol 1113 ◽  
pp. 800-805 ◽  
Author(s):  
Baljit Singh ◽  
Muhammad Fairuz Remeli ◽  
Alex Pedemont ◽  
Amandeep Oberoi ◽  
Abhijit Date ◽  
...  
Keyword(s):  
Large Scale ◽  
Heat Storage ◽  
Salinity Gradient ◽  
Heat Energy ◽  
Working Fluid ◽  
The Sun ◽  
Solar Ponds ◽  
Solar Pond ◽  
Evacuated Tube Collectors ◽  
Evacuated Tube

This paper investigates the capability of running a system which uses hot fluid from solar evacuated tube collectors to boost the temperature and overall heat storage of the solar pond. The system is circulated by a solar powered pump, producing heat energy entirely from the incoming solar radiation from the sun. Solar evacuated tube collectors use a renewable source of power directly from the sun to heat the working fluid to very high temperatures. Solar ponds are emerging on the renewable energy scene with the capacity to provide a simple and inexpensive thermal storage for the production of heat on a large scale. The results of the performance of the system show a significant heat energy increase into the solar ponds lower convective region, increasing the overall performance of the solar pond.

scholarly journals The investigation of using phase change material for solar pond insulation

2021 ◽  
pp. 185-185
Author(s):  
Ismail Bozkurt
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Salt Water ◽  
Capric Acid ◽  
Heat Energy ◽  
Solar Ponds ◽  
Solar Pond ◽  
Enthalpy Changes ◽  
Selection Of

Solar ponds are systems that store solar energy in salt water as heat energy. In order to store heat energy for a long time in solar pond, the heat insulation should be done well. In this study, the effect of phase change materials (PCMs) was investigated to improve the insulation of the pond and to store the heat energy for a longer time. The melting temperature is a key parameter in the selection of PCMs. The temperature distribution of the solar pond was examined and PCMs with melting temperatures in the range of the pond average temperature ? 10?C were selected.Three different phase change materials were used in the walls of the solar pond for insulation. The temperature and enthalpy changes of the system were calculated numerically for a year. The heat storage ratio of the solar pond was determined by using the obtained enthalpy and solar radiation data. Consequently, the heat storage ratio of the pond with glass-wool is maximum 20.95% in July and minimum 7.92% in January. The heat storage ratio of the solar pond which Paraffin C18, Capric acid and Paraffin 44 are used as PCMs is maximum 32.22%, 34.85% and 47.81% in December, respectively. It is observed that the appropriate selection of PCMs is provided a longer storage time for solar ponds.

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.

Experimental and numerical investigation of thermal convection in a water saturated porous medium induced by heat exchangers in high temperature borehole thermal energy storage

2021 ◽  
Author(s):  
Victorien Djotsa Nguimeya Ngninjio ◽  
Wang Bo ◽  
Christof Beyer ◽  
Sebastian Bauer
Keyword(s):  
Porous Medium ◽  
Temperature Distribution ◽  
Heat Transport ◽  
Thermal Convection ◽  
Heat Storage ◽  
Saturated Porous Medium ◽  
Storage Unit ◽  
Thermally Induced ◽  
Water Saturated ◽  
Storage Temperatures

<p>Borehole thermal energy storage is a well-established technology for seasonal geological heat storage, where arrays of borehole heat exchangers (BHE) are installed in low permeability geological media dominated by conductive heat transfer. Increasing storage temperatures would increase storage capacities and rates and would thus allow for a better inclusion of BTES in the energy system. When using storage temperatures of up 90°C, however, highly permeable zones or intermediate layers may allow for thermally induced fluid migration and convective heat transport in the storage medium, which may increase heat losses from the storage and thus limit the thermal performance of the BTES system. Therefore, we present results from experimental work and subsequent numerical modelling aimed at quantifying thermally induced convection for a lab-scale BHE in a water saturated porous medium for a temperature range of 20°C to 70°C.</p><p>The experimental heat storage unit consists of a fully water saturated coarse sand within a cylindrical polypropylene barrel of 1.23 m height and 0.6 m radius and a vertical coaxial BHE, which is grouted by a thermally enhanced cement. The barrel is cooled from the outside using ventilators and laboratory air. A grid of 68 thermocouples is emplaced in the storage medium for monitoring the temperature distribution. For the stationary experiment, heat is transferred to the storage unit using a supply temperature of 70°C for 6 days until a steady state temperature distribution is achieved, followed by 3 days of heat recovery. The dynamic experiment begins with 3 days of heating with 70°C followed by 6 cycles of alternating heating at 70°C and cooling at approximately 18°C for 12 hours each.</p><p>The stationary experiment reveals a vertical temperature stratification, with temperatures increasing up to 48°C towards the top of the porous medium, as well as a horizontal temperature gradient along the top of the sand, while the lower part of the barrel and the outer wall remain at the laboratory temperature of approximately 18°C. This temperature distribution has stabilized after about 90 hours and represents a clear tilted thermal front, suggesting a significant contribution of induced thermal convection to the overall heat transport. The cyclic experiment shows a decrease of storage temperatures relative to the stationary experiment, with temperatures near to the BHE at the top of the porous lower by 2.5°C and 4.75°C, respectively, because the heating phase is not long enough to reach the stationary temperature distribution. This lower horizontal temperature gradient indicates a weakened thermal convection, however the thermal stratification is conserved. This shows that even under the cyclic loading conditions thermal convection may impair high temperature BTES operation and efficiency.</p><p>Numerical process simulation of coupled flow and heat transport accounting for variable density and the experimental boundary conditions reproduces the spatial and temporal temperature distribution of both experiments with good accuracy. This shows that induced thermal is causing the observed temperature distributions.</p>

Experimental Investigations on Salt Gradient Solar Pond with Additional Non-Convective Zone for Improved Thermal Performance and Stability

2021 ◽  
Vol 43 ◽  
pp. 59-71
Author(s):  
Devendra B. Sadaphale ◽  
S.P. Shekhawat ◽  
Vijay R. Diware
Keyword(s):  
Heat Storage ◽  
Salinity Gradient ◽  
Convective Zone ◽  
Salt Flux ◽  
Maximum Temperature ◽  
Experimental Investigations ◽  
Thickness Variation ◽  
Salty Water ◽  
Solar Pond ◽  
Salt Gradient

Salt gradient solar ponds are to be designed for thermal efficiency and salinity profile stability. As the salt flux moves upward in the pond, the gradient gets destabilized. This is counteracted by intrusion of salt at different levels as and when required. The density of salt is highest at the bottom and minimum at the top. Hence the destabilization effect is more at top that is at the interface of upper convective zone and non-convective zone (NCZ). In order to keep the interface stable, it is desirable to provide a higher slope of salt gradient near it. However, throughout the non-convective zone, it is not feasible to provide higher slope due to solubility limitations. Hence Husain et al (2012) to divide the NCZ into two parts. The top few centimeters may be given a higher slope and the rest of the zone may be given mild slope as usual. Husain et al (2012) have given analysis for the same and found it to be feasible. However, the experimental feasibility of the same needs to be verified. The present work has done an attempt for the same. In this study, an insulated solar pond with a surface area of 1.40 m2and a depth of 1.14 m is built at the SSBT’s College of Engineering and Technology, Jalgaon in the Maharashtra State (India). The three salty water zones (upper convective, non-convective and heat storage) were formed by filling the pond with salty water of various densities. 6 Thermocouples (type Pt100A) (C+0.2%) were used to measure the temperature profile within the pond. A maximum temperature of 47°C was recorded in the heat storage zone in time span considered for study. The results obtained from experimentation is verified with the concept suggested by Hussain et al (2012) it has been found that they are in a good agreement. The influence of varying the thicknesses of the zones present in a salinity gradient solar pond on the temperatures of the upper convective zone (UCZ) and the lower convective zone (LCZ) is investigated. Also, it is found that by adding the additional non convective zone of 50 mm thickness above the UCZ the heat collection capacity of the LCZ is increased noticeably. The study finds that thickness variation of the zones within the pond is a practical feasibility. The system worked for the entire experimental duration effectively without failure.

Effect of Water Distribution Ways on the Operation of Solar Pond

2013 ◽  
Vol 805-806 ◽  
pp. 74-77
Author(s):  
Chun Juan Gao ◽  
Qi Zhang ◽  
Liang Wang ◽  
Ying Wang ◽  
Xi Ping Huang
Keyword(s):  
Water Distribution ◽  
Salinity Gradient ◽  
Convective Zone ◽  
The Body ◽  
Solar Ponds ◽  
Solar Pond ◽  
Storage Zone ◽  
Small Model ◽  
Laboratory Tank ◽  
Salt Diffusion

An experimental study on the evolution of the salinity profiles in the salinity gradient solar ponds was executed using a small model pond. The body of the simulated pond is a cylindrical plastic tank, with 50 cm height and 45 cm diameter. The salinity gradient was established in the laboratory tank by using the salinity redistribution technique. The measurements were taken during a period of 20 days of experimentation. This period of time allowed the existence of salt diffusion from the storage zone to the surface. Results obtained from this study show that when the ratio of brine/water is 1/1, the salinity gradient layer can sustain a longer time and the lower convective zone is thicker, which is benefit to store solar energy.

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