Redundant Heat Exchanger Scheme for Closed Loop Air-to-Liquid Cooling System
Original Publication Date: 2004-Sep-07
Included in the Prior Art Database: 2004-Sep-07
A redundant air-to-liquid heat exchanger scheme for use in a closed loop air cooling system for electronic units is described. The scheme utilizes two air-to-liquid heat exchangers that may be rotated into the air flow path as required. A single motor with belts driving a pulley on each heat exchanger is used to swing the heat exchangers in and out of the air flow path. Each heat exchanger is supplied cooling liquid from a separate source.
Redundant Heat Exchanger Scheme for Closed Loop Air -to-Liquid Cooling System
A redundant heat exchanger scheme is disclosed for use in a closed loop air-to-liquid cooling system such as described in Ref. 1. In a system of this type, air is circulated in a closed loop through a compartment housing heat dissipating electronics units and then through an air-to water heat exchanger, as shown in fig. 1. All of the heat dissipated is rejected to cooling water flowing through the heat exchanger and no heat is exhausted to the room air.
Air flow loop Front cover
While this approach is advantageous it is dependent on a continuous flow of cooling water through the air-to-liquid heat exchanger. A loss of cooling water for any reason will cause air temperatures within the enclosure to rise and could make it necessary to shut-down the computer. In larger server installations high availability (i.e. percentage of time the computer is operating) is a major requirement and unplanned shut-downs cannot be tolerated. To meet such requirements a totally redundant and independent supply of cooling water may be provided to the air-to-liquid heat exchanger. To take advantage of a dual source of water two separate and independent water flow paths would have to be built in to the heat exchanger. This would double the number of tubes and require increased fin surface area. The air flow pressure drop across this larger heat exchanger would be greater and adversely impact the total flow of air, decreasing the amount of air flow over the heat dissipating electronics.
The redundant heat exchanger scheme disclosed herein solves the problem by utilizing two conventional air-to-liquid heat exchangers with each being fed by a separate and independent supply of cooling water. Each heat exchanger is supported on its own shaft and is capable of being rotated into the air flow stream when required. The heat exchanger that is rotated into the air flow stream removes the system heat load from the air while the other remains in a standby...