Design and development of a passively cooled remote outdoor cabinet

In many electronics/telecommunication applications, switching/signal-processing equipment is commonly placed in outdoor cabinets. The housed equipment generates heat that is while keeping the air temperature inside the cabinets within prescribed limits for optimum performance. Furthermore, the enclosure, being outdoors, receives full solar irradiation, creating an extra heat load that must be handled. Although most cabinets are sufficiently large to allow for active cooling systems, smaller cabinets must meet thermal requirements by passive means only, thus imposing unique restrictions. One way to effect such requirements is to use natural convection and solar radiation shields. The focus of this paper is to present results on experimental and numerical studies used in the design, development and testing of an outdoor cabinet that would operate in full solar loads without the input of power. The cabinet features a unique natural convection heat sink that is shrouded for higher efficiency. This heat sink was especially designed by Teltrend and MJM Engineering to meet the thermal requirements for the cabinet. The enclosure was fully simulated using Icepak^TM, a CFD software package by Fluent, Inc., to ascertain the thermal performance of the heat sink and that the cabinet met thermal requirements. In house tests were conducted using simulated solar loads in a temperature-controlled chamber to corroborate the CFD simulations and the thermal design. Results show that the heat sink effectively removes the heat from the cabinet without using fans. Furthermore, the cabinet as a whole meets the thermal requirement