Thermal design of a Base Transceiver Station using Flow Network Modeling

The objective of the present study was to perform thermal analysis for the design of a Base Transceiver Station (BTS) outdoor frame, which consists of a PCB rack, an ATM switch unit, a RF amplifier unit, two RF filters and a rectifier. The electronic components are completely isolated from the outside ambient air. The primary objective of the analysis was to package all these units into a compact portable cabinet with effective cooling strategies for outdoor environmental conditions. The Flow Network Modeling (FNM) technique was used for the thermal analysts from conceptual design through the final design. At the conceptual design phase, flow network models were built to examine different packaging concepts and to generate new design proposals by identifying the problem areas of the examined design concepts. A highly integrated heat exchanger/BTS frame design concept was developed after iterations of this process. At the detailed design stage, FNM analysis was used for the placement of units, for necessary air baffling and flow balancing and for the design of the heat exchanger. The results of system-level FNM analysis were also used in the unit-level analysis using Computational Fluid Dynamic (CFD) technique. The use of NFM technique benefits this design in its ability to provide quick system-level modeling and problem solving. A CFD analysis for the BTS frame with detail heat exchanger and heat sink models, which are critical for the design, requires tremendous modeling effort and computational time and is not feasible nor necessary at the early design stage. Use of FNM shortened the design process significantly.