| There is a large rural population in China and there are many heating methods in winter,of which Kang is a very popular heating style,but it becomes increasing obviously disadvantages with large heating energy consumption and low thermal efficiency in rural areas.In order to solve the problems of pollution and improve the sleeping environment for rural aged persons and children at night,a kind of economic energy storage Kang is put forward combined with utilization of solar energy and phase change material(PCM)storage technology.For economic considerations,an end device is made of PCM storage Kang composited by paraffin and concrete(paraffin-concrete Kang)and concrete Kang.Based on the research of the existing heating technology and the application of solar energy storage Kang,the working principle and heat transfer process of Kang system are deeply analyzed,the requirement quantity of the paraffin is 14.3kg for paraffin-concrete Kang,the total heat load is 17.19 MJ during the day and night.The experimental system is designed and selected,according to the human body's requirement for storage Kang temperature,the experimental scheme,experimental test contents,measuring points arrangement and control system are determined.According to the human thermal comfort requirements and the melt characteristics of paraffin,the comparisons are made with the flow rate of 0.95L/min and 1.41L/min at the set temperature of 35?,40? and 45? respectively for the paraffin-concrete Kang and the concrete Kang,the thermal properties of paraffin-concrete with the other three kinds of Kang are studied.The results show that:1.With the increase of heating temperature and water supply,the thermal performance indexes of the storage Kang basically increased.At 35? and 0.95L/min,the temperature of the paraffin-concrete Kang at night is 31.32?,the sleeping temperature is 29.5?,the temperature difference of the Kang surface is about 4?,the heating rate of the Kang surface is 1.54?/h,the cooling rate is 0.22?/h,and the Kang surface heat flux is kept at 10.01W/m2;the temperature of the concrete Kang at night is 26?,the sleeping temperature is 24.3?,the temperature difference of the Kang surface is about 7.5?,the heating rate of the Kang surface is 1.62?/h,the cooling rate is 0.67?/h,and the minimum heat flux at night can be as low as 5.84W/m2.2.Compared with the traditional Kang,the paraffin-concrete Kang surface temperature is evenly distributed,the average temperature of the Kang surface is 31.32?,which is 10? higher than that of the traditional Kang,and the cooling rate of the Kang surface is only 15% of the traditional Kang,it poses good insulation performance.3.By comparing with the concrete Kang,the paraffin-concrete Kang is better than the concrete Kang in the evaluation index of the thermal properties.At night,the temperature of the Kang surface is 5.00? higher than that of the concrete Kang,and the heat flux density is stable at 10.01W/m2,while the heat flux of the pure concrete Kang can be as low as 5.84W/m2.The paraffin-concrete Kang can effectively improve the heating effect in winter.4.The paraffin-concrete Kang structure is compactly,the initial investment cost is low.Compared with the paraffin Kang,it can save 30% of the cost and can meet the requirements of heating comfort in winter,It has the highest cost-effective in heating.Finally,the melting and solidification simulation of the paraffin-concrete Kang has been done.The simulation results show that the melting rate of paraffin increased gradually with the increase of temperature,and the temperature of Kang surface on the process of heat storage and exothermic process basically coincided with the experimental results. |
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