Use of a water plenum and thermosiphon to control peak temperature in outdoor cabinets

Tests conducted at a Bellcore thermal test facility demonstrate that the temperature in a typical 12-ft/sup 3/ unpowered telecommunications power supply cabinet, with 3 inch thermal insulation and a 20 gallon water plenum and thermosiphon, can be held to between 30 and 80 degrees F. The upper limit of 80 degrees F was not exceeded even after a week of sunny days and peak outdoor temperatures approaching 95 degrees F. In wintertime tests, water temperature did not go below 32 degrees F, and the air temperature inside the cabinet did not go much below 30 degrees F. There was enough water to prevent complete freezing. These measured results tracked well with predicted inside temperatures determined using a previously developed thermal model and support the use of the model to predict results in other climates and for other cabinet parameters, such as size and amounts of insulation. >