CAJ | 학술논문

针对冷冻冷藏库传统除霜方法高能耗、冷库温湿度波动大等缺陷，通过设计系统除霜结构，完善控制策略，研发了一种智能除霜方法。复合加热循环除霜采用时间—压差联合智能控制策略界定最佳除霜点，配备排管辅助制冷技术，基于欧姆龙PLC高精度控制系统使各设备协同完成除霜过程。对复合加热循环除霜系统进行试验研究，对比分析不同除霜方法的工作性能及能耗情况。结果显示：相比于传统电加热除霜，复合加热循环除霜过程冷库温度波动减小3.8℃，相对湿度波动降低21.1百分点，除霜时间缩短14 min，系统除霜节能率达34.5%。
침대냉동랭장고전통제상방법고능모、랭고온습도파동대등결함，통과설계계통제상결구，완선공제책략，연발료일충지능제상방법。복합가열순배제상채용시간—압차연합지능공제책략계정최가제상점，배비배관보조제랭기술，기우구모룡PLC고정도공제계통사각설비협동완성제상과정。대복합가열순배제상계통진행시험연구，대비분석불동제상방법적공작성능급능모정황。결과현시：상비우전통전가열제상，복합가열순배제상과정랭고온도파동감소3.8℃，상대습도파동강저21.1백분점，제상시간축단14 min，계통제상절능솔체34.5%。
In recent years, mini cold storage house has developed rapidly. The evaporator is extremely easy to frost as a result of locating in the condition of low temperature and high humidity. However, defrosting energy consumption accounts for more than 10% of system’s total energy consumption. To overcome the defect about high energy consumption, temperature and humidity fluctuation of traditional defrosting technology in mini cold storage house, we investigated a new framework by changing the structure of the defrosting system and optimizing the control technology. Firstly, we developed a new defrosting system named as recombination heating circulation defrosting (RHCD) based on overhead coil auxiliary refrigeration. After that, the time-differential pressure (TDP) combining intelligent control method was used innovatively to determine the best defrosting point. Finally, OMRON programmable logic controller was applied to combine some devices to finish the defrosting. In the defrosting process, the electric-air valves installed on the incubator were closed timely to restrain heat and vapor into the cold storage house, and hot air flow was forced to circulate in the bypass channel under the working of blowers. Meanwhile overhead coil auxiliary refrigeration system was started to maintain stability of temperature and humidity. After defrosting, coil auxiliary refrigeration system was terminated and the electric-air valves were kept closed to finish cooling and dehumidification of incubator until temperature of incubator was reduced to be consistent with cold storage house. Accurate and complicated logic control of RHCD system, including TDP method and the working about some defrosting devices, was based on OMRON programmable logic controller. This paper made theoretical analysis and simulation about temperature and velocity field of the defrosting process by COMSOL. The results showed that RHCD has higher heat transfer coefficient between air and frost for the reason that incubator has higher air velocity (2 m/s) and steady-state temperature. Moreover, we also completed an experimental research to analyze the working performance and energy consumption of RHCD and other methods. The results showed that RHCD, compared with the traditional electric heating defrosting (EHD), reduced the fluctuation of temperature by 3.8 degrees and relative humidity by 21.1%. Defrosting time was shortened by 14 minutes. Energy consumption of electric heater was decreased by 50 percent and energy-saving rate could reach 34.5 percent in total defrosting process. The RHCD can not only improve performance of food preservation but also save energy efficiently.