| In order to deal with the energy crisis and slow down the greenhouse effect,the development and utilization of new energy becomes more and more important.At present,energy transformation is a long-term and arduous task faced by our country,and the transformation of traditional power generation is the most important thing in the power industry.Among the many renewable energy power generation,solar thermal power generation has broad prospects for development.But because of its intermittent,can not be stable output,and the heat storage system can just solve this problem.In the thermal storage system,the sensible heat storage system has the earliest development,good stability and relatively cheap price,and has been widely used in solar thermal power generation.In the research of sensible heat storage system,the application of heat storage materials is the most critical.Concrete is a kind of material with low cost,stable thermal performance,and can be used in a large amount of industrial production under appropriate conditions,so it is of great significance to study its heat storage system.This paper uses simulation software to simulate the heat storage and release of high temperature concrete heat storage system.Firstly,the heat storage and release characteristics of concrete heat storage system under fixed parameters are studied.The results show that the heat storage/release rate decreases with the increase/decrease of concrete temperature during the heat storage/release process.When the concrete temperature rises/falls to 60℃,the storage/release time of the heat storage system is496.3s/420.2s,and the storage/release heat is 3.25MJ/2.69 MJ.When the temperature rise/fall of concrete is 100℃,the storage/release time of the heat storage system is 1418.5s/1651 s,and the storage/release heat is 5MJ.At the same time,the internal temperature distribution of the system is also studied,and it is concluded that the temperature of the concrete changes little along the model length direction,and the temperature change degree of the concrete perpendicular to the model length direction is greater than the temperature change degree along the concrete length direction.Secondly,the influence of the concrete thermal conductivity and the arrangement of heat exchange pipe on the heat storage model is studied.The simulation results show that when the thermal conductivity of concrete is increased by 25%,50% and 100%,the storage/release time of concrete heat storage model is reduced by 15.9%/15.3%,26.1%/25.6% and 38%/38.2%.The results of the study on the influence of pipeline arrangement on heat storage and release show that model 3,namely four-pipe concrete heat storage model,has the highest utilization rate of heat transfer fluid,saves more space and is more convenient when multiple heat storage devices are coupled.At the same time,the optimization of the storage and release characteristics of the heat storage device by adding fins is also investigated.The results show that the storage and release time of the heat storage model with 4 fins can be reduced by 14.6%,and that of the heat storage model with 6 fins can be reduced by 22.8% and 23.2%.Finally,the characteristics and economy of heat storage and release under multi-module coupling are simulated.The results show that scheme 6(three modules connected in parallel)has the fastest speed of heat storage and heat release,scheme 3(three concrete modules connected in series)has the slowest speed of heat storage and heat release,but the most stable rate.In the economic analysis,the unit storage and heat release cost of scheme 3 is the lowest 17.89USD/k W·h;Scheme 2(three cast steel modules in series)the highest unit cost of heat storage and release is 76.22 USD/k W·h;Based on the above analysis of the characteristics and economy of heat storage and release in multi-module coupling,it is concluded that scheme 3 and 6 can be applied to large-scale heat storage. |
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