Experimental And Computational Study On Radiation Transmission And Double-diffusion Characteristics Of The Seawater Solar Pond

The seawater solar pond utilizes seawater and salt-work bittern as its working media. The solar pond can collect and storage the solar energy and provide a low temperature heat resource for various applications. Because of its simplicity and lower running cost, over recen years the solar pond has been widely recognized and studied intensively around the world.This thesis is focused on the thermal performances of the seawater solar pond and the following work has been cerried out1.Physical and mathematical models for the seawater solar pond was presented. The basic heat balance model,the temperature-salinity double diffusion model and the thermal stability model were discussed.Based on this, the stability conditions and interface growth behavior in solar pond are discussed.2. Mathenatical expressions for the Dalian's solar radiationand air temperature and soil temperature were formulated based on measurement data.3.The turbidity of water is one the main factors affecting the thermal efficiency of the solar pond, so increasing water clarity can increase the operation efficiency of the solar pond. To do this,a method of filtration combined with chemical medicament to reduce the turbidity of bottern and raise the solar pond efficiency was experimentally studied.4.In-door experiments for the density and turbidity diffusion in the bittern, both original and treated, and for the clarifying of rainwater as well as for the bedload sediment were performed, which provided a basis for the running and maintenance of the solar pond.5. the construction and filling of a seawater solar pond were carried out. With continuous chronic measurements, a great amount of data about temperature, turbidity and salt concentration distribution and evolution are acquired.6.Based on the experimental data, a relationship between the transmission of solar radiation and the pond depth at different turbidities was established, that is useful for the thermal performance research of solar ponds.7. One and two dimensional numerical simulations for the transient performance of the solar pond were conducted. Effects of the turbidity and reflectivity at the pond bottom were studied. Specially, the Soret effect was investigated and the results show that this effect should not be neglected over a long running time.The experimental and the numerical investigation of this thesis produce some important results about the thermal characteristics of the solar pond which can be useful and referenced for further research and also for the practical construction and operation of the solar pond.