Research On Energy Saving And Cooling Of The Tower Crane Jacking Hydraulic System

In recent years,with the rapid development of China’s economy,high-rise and even super high-rise buildings rise.Because of its advantage in construction height,tower crane has become the first choice of modern construction machinery.Jacking mechanism is an important mechanism to realize automatic height change of tower crane,and hydraulic system is usually used as power and control source.However,in the later period of continuous jacking operation,oil temperature in the hydraulic system is often too high,which not only affects the jacking performance,but also causes the waste of energy.Nowadays,with the energy crisis and environmental pollution becoming more and more serious,countries around the world have started to implement the development concept of energy conservation and emission reduction.Therefore,it is of great significance to research the energy saving and cooling of jacking hydraulic system of tower crane.This paper takes the jacking hydraulic system of a certain type of tower crane as the research object,aiming at the problem that the pressure loss of hydraulic oil is sent into the system in the form of heat energy to raise the system temperature during jacking operation,the simulation analysis is carried out and the energy-saving cooling scheme is designed.By analyzing the working principle and process of tower crane jacking hydraulic system,the thermodynamic model of jacking hydraulic system is built by using the relevant components in AMESim software such as hydraulic,Thermal hydraulic,signal,THCD and Thermal library.Simulation conditions are set for different stages of tower crane jacking,and the thermal model is verified by calculating the heating and cooling power of the system with the knowledge of thermodynamics.The thermal model is used to simulate under the given simulation conditions,and the simulation results show that:(1)When the environment temperature is 25℃,the system temperature reaches 92℃,after 6 standard nodes of continuous jacking,which is beyond the normal operating temperature range of construction machinery oil of 50℃～80℃.(2)Through the simulation of different factors affecting the jacking hydraulic system temperature,it can be seen that the excessive oil temperature is caused by insufficient system heat dissipation under the condition of natural heat dissipation.Therefore,it is necessary to add a cooler to the jacking hydraulic system.By comparing the common coolers in the hydraulic system,it is determined to use the forced air-cooled radiator to cool the hydraulic system.This paper designs a new energy-saving cooling tank,starting from the concept of energy conservation and emissions reduction development of national advocacy,based on the seebeck effect and thermoelectric principle.The tank generates electricity by taking advantage of the temperature difference between oil and the environment,forming a continuous current to drive the fan for air-cooling and heat dissipation.Controlling the temperature rise of thejacking hydraulic system without additional power,and ensure the normal operation of the jacking system,and the secondary utilization of waste heat energy is realized.Through the simulation analysis of the cooling capacity of the energy-saving cooling system by AMESim software,it can be seen that the application of air-cooled radiator can ensure that the system can work within the suitable range of 60℃～70℃.It indicates that the cooling capacity of the air-cooled radiator is good.The feasibility of the energy-saving cooling design in this paper is verified by the experiment of the self-made energy-saving cooling tank model.Through the research on energy saving and cooling of jacking hydraulic system,this paper provides reference for the research of other construction machinery,and has certain practical value.