Numerical Investigation into the Air Flow Distributions of the Air Conditioning System in the Modular Data Center

Abstract

Data center plays an increasingly important role in everyday life. As data center is becoming more and more powerful, energy consumption is also increasing dramatically. The air conditioning system occupies at least 50 percent of the total energy consumption. Therefore, delicate analysis on the air conditioning system could help to reduce energy consumption in data center. An advanced Finite Volume Method with RNG k−ε model and convective heat exchange model is used in this paper to study the airflow and the temperature distribution of modular data center under different arrangements. Specifically, the calculation formula of convective heat transfer coefficient for plate flow is adopted to simplify analysis; and fans on the back of racks are simplified to be walls with a certain pressure jump. Simulations reveal that, in the case where air conditioners are arranged face-to-face, the temperature distribution on the back of racks is not uniform, and local high temperature points emerge near the side wall of air conditioners. By analyzing the distribution of air flow and temperature, geometric model is optimized by using a diagonal rack arrangement and drilling holes on the side wall. In the same energy consumption situation, the overall maximum temperature of the optimized model is reduced by 2.3 • C compared with that of the original one, and the maximum temperature on the server surface is reduced by 1 • C. Based on the optimized model, the effect of the hot aisle distance on the temperature distribution is studied. By simulating four different cases with various distances of hot aisle of 100cm, 120cm, 130cm and 150cm, it is found that the temperature is generally lower and distributed more evenly in the case with 120cm hot aisle distance. This demonstrates that the distance of hot aisle has an effect on temperature.

CFD Investigation of Vehicle’s Ventilation Systems and Analysis of ACH in Typical Airplanes, Cars, and Buses

“…The base mesh and set-up of the discrete model was done according to the recent studies on aerosol transmission [33,[66][67][68]. To solve the Navier-Stokes equations in the simulation model, the k−ε turbulence method was used as the performance has been verified in similar case studies [68][69][70][71][72]. For simulation, we used a detailed 3D-CFD model in the steady condition, and for the CFD analysis, we used the ANSYS Fluent package.…”

The Role of HVAC Design and Windows on the Indoor Airflow Pattern and ACH

“…For decreasing the error and uncertainty in the mesh, the details of the models are simplified, particularly for the human bodies, as recommended in previous studies [93,94]. The turbulence method of k−ε has been selected for the simulation since the performance was verified in similar case studies [95][96][97][98][99]. For decreasing the simulation error, the suggested methodologies in the previous studies have been considered for airflow pattern simulation [100], and for the discrete modeling, the recent studies on aerosol transmission have been considered [93,97,101,102].…”