Steady-state Simulation And Performance Research Of A Thermosyphon And Mechanical Refrigeration Hybrid Cabinet-cooling System For 5G Base Station

With the development of the 5G communication technology,a single base statio n has accommodated more communication equipment,and the power of the equipment has greatly increased.5G base stations have faced prominent difficulties of decreasing cooling energy consumption and ensuring the working safety of the communication equipment.Thermosyphon is widely used in base station cooling system because of it can make full use of free cooling.So that the thermosyphon has high energy saving potential.However,thermosyphon can only work in cool season,mechanical refrigeration systems are indispensable in hot season for auxiliary cooling.In recent years,many scholars have developed different forms of hybrid cooling system which couples a thermosyphon with a mechanical refrigeration system and carried out research on it.Based on a new type of hybrid cabinet-cooling system,the dynamic and steady-state performance of the cooling system are analyzed through field measurement and steady simulation,so as to exert its energy saving furtherly.Firstly,a new type of hybrid cabinet-cooling system which couples a thermosyphon with a mechanical refrigeration system is developed.By comparing the characteristics of the previous hybrid cooling system with it,the innovation of the form of coupling in this system is pointed out,and the working pri nciple and the system form are introduced in detail.Secondly,through the field study,the dynamic performance and the equipments’thermal safety in transition season are explored.The air distribution and the energy efficiency of the system are also anal yzed.The results show that the cooling system can ensure the safety of the equipment under normal mode,and its power usage efficiency is 1.59.In thermosyphon mode,its PUE is 1.31.When the cabinets are placed paralleled,opening one side of the cooling system can not only realize fault backup,but also realize the effect of energy saving.However,the start-up temperature of the mechanical refrigeration and the air volume of the fan still need to be further optimized.Finally,the steady heat transfer model of the hybrid cooling system is established,and the predicting accuracy of this model is verified through test.Through simulation,the optimal refrigerant charge of thermosyphon is explored,and then the working performance under different outdoor t emperature is simulated to determine the applicable range of outdoor temperatures under three operating modes that are thermosyphon mode,dual mode and the refrigeration mode.The working performance of the system under three operating modes is also analyz ed.By simulating the performance of the hybrid cooling system under different air volume of heat exchangers,the optimal air volume under three operating modes is determined.The results show that when the difference between indoor and outdoor temperature is greater than 18℃,the system works in thermosyphon mode.The optimal filling refrigerant charge is between 1.6-1.8kg,and the optimal air volume of both evaporator and condenser is 3000 m~3/h.When the difference between indoor and outdoor temperature is between 6℃and 18℃,the system works in dual mode.The optimal air volume of both evaporator and condenser is 2000 m~3/h.When the difference between indoor and outdoor temperature is less than 6℃,the system works in refrigeration mode,and the optimal air volume of both evaporator and condenser is1500 m~3/h.