Analysis And Experimental Research On Thermal Performance And Turbidity Of Salt Gradient Solar Pond

The salt gradient solar pond is one of the devices that can efficiently use solar energy.The quality of the salt gradient solar pond is reflected by the heat absorption performance and heat storage performance.The heat absorption performance and storage performance of the solar pond is reflected by salinity and turbidity.The method of experiment combines with theoretical analysis is used this paper.The thermal performance and turbidity of the salt gradient solar pond are studied in this paper.First of all,the small solar pond is made to be research object in this paper.The temperature distribution of solar pond with a salt gradient of 0.323%/cm and 0.269%/cm are studied.And the influence of turbidity on the thermal performance of each layer in the solar pond is analyzed by the light absorption and scattering theory.The results show: the rate of temperature change gradually rises as the depth of solar pond increases.The temperature change rate and temperature are maximum at 2/5～3/5 depth of the lower-convective zone.The solar pond with the salinity gradient of 0.323%/cm has better heat storage and insulation performance than the solar pond with the salinity gradient of0.269%/cm.The reference is provided for heat utilization of the salinity gradient solar pond by the conclusions.In the salt gradient solar pond,the non-convective zone NaCl molecules concentration,the number of suspended particles and the particle size are increased can lead to the non-convective zone light absorption and light scattering are increased,and the lower-convective zone heat storage efficiency is also reduced.However the lower-convective zone NaCl molecules concentration,the number of suspended particles and the particle size are increased is conducive to the heat storage efficiency of the lower-convective zone.The importance of turbidity reduction in the solar pond is explained and the theoretical basis is provided for turbidity reduction by conclusions.Secondly,the turbidity change curve at 0.8L position in the salt solution with salinity of 1%～23% is obtained by monitoring the change of turbidity at the same position in 1L salt solutions with different salinities.The conclusions are obtained by combination of experiment and buoyancy theory analysis,calculation.The conclusions show: the salinity of the salt solution is increased can lead to the density of the salt solution and the buoyancy of the suspended particles is increased,and also can lead to the sedimentation speed of the suspended particles is gradually decreased.For every 1% increase in salinity,the free sedimentation speed decreases by 4.5%.The theoretical basis is provided for the salt gradient layer setting by the conclusions.Finally,the aggregation performance of non-ionic polyacrylamide is tested on the basis of the turbidity sedimentation study.The conclusions show: the clarification rate of the salt solution with 0.1% non-ionic polyacrylamide is 5/7 of that without addition.The clarification rate of the salt solution with 0.3% non-ionic polyacrylamide is 4/7 of that without addition.The aggregation performance of polyacrylamide is proved to be good by the conclusions.