| Recent years have witnessed a rapid expansion of both the distribution and the number of communication base stations with the speedy development in mobile communication equipment. Meanwhile, energy saving in the communication base stations has also been gaining increasing attention because energy consumption by air conditioning system takes up about 30% to 45% of total energy consumption and is still on the rise in the construction and operation of communication systems. Traditionally, the whole machinery room in the base station is the cooling object, which consumes quite a large amount of power. Nowadays, some equipment cabinets are designed as total closed structures with air-conditioner mounted on the roof. Compared with the open structure, power consumption by equipment cabinets with such design are lowered greatly. IT equipment is vulnerable to overheating and dust is one of the factors resulting in overheating. Therefore, they are usually set in enclosed machine rooms to achieve dust prevention. Those machinery rooms with more reasonable integrated design are more practical, advanced, expandable, manageable and maintainable.This paper conducts an investigation on the equipment cabins with total closed structure and roof-top air conditioner in the data room in a certain communication company. Numerical simulation on roof-top air conditioner and simulation on thermal environment through the CFD commercial software FLUENT are performed to attempt to gain accurately the operational environment in the machine room. The investigation mainly is concerned with the following three aspects.First of all, the inner environmental temperature standard of the data rooms is obtained by referring to materials available and the outside temperature is also determined through an analysis of the factors influencing the simulations. Based on the structure and parameters of the roof-top air conditioner, the air-conditioning system and each of its components are numerically simulated through C Language to get its performance and supply air temperature. In addition, numerical simulation results show that the whole system is appropriate to the model of individual components.Secondly, in order to examine the influence of outlet air temperature on inlet air temperature, UDF is programmed by resorting to C Language. Meanwhile, a simplified physical model of the communication base station is established after field measurement and appropriate Continuity Equation, Momentum Conservation Equation, Energy Conservation Equation, k-s Equation, and Boundary Conditions and Initial Conditions are employed to carry out the numerical simulation calculation on the thermal environment in the base station through the simulation software CFD. Then the airflow velocity field and temperature field distribution in the base station are figured out when the influence of the inner temperature on the inlet air temperature becomes stable by utilizing the program UDF. From the results of simulation, air flow organization in the data room is not reasonable.Finally, through the numerical simulation analysis on roof-top air conditioner, the performance of the air-conditioning system and the influence of indoor and outdoor temperature change on the performance of air-conditioning system are identified. Numerical simulation results show that with the indoor temperature rising, the evaporation temperature, the condensation temperature, and the energy efficiency ratio also increase and with the outdoor temperature rising, the condensation temperature increases and the energy efficiency ratio decreases, but the evaporation temperature is not obvious. |
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