| 摘要 |
A method and apparatus for removing moisture from within an electronics enclosure is provided. In particular, dehumidification is accomplished by removing air from the enclosure, cooling the air thereby causing condensation of water vapor from the air, then heating the dehumidified air and returning the heated and dehumidified air to the enclosure. A single heat pump provides cooling and heating functions, effectively recouping heat extracted from the air to be cooled, and transferring the extracted heat to the air prior to its return to the enclosure. In this manner, electronics within the enclosure may be operated at temperatures below the dew point of ambient air surrounding the enclosure, without requiring a thermally insulated enclosure. Devices are provided to collect and purge condensate from the system, either in a continuous or periodic manner. Embodiments employing conventional vapor compression cycle heat pumps and thermoelectric heat pumps are described. A defrost cycle is provided to eliminate frost that may accumulate on the heat exchanger associated with the heat pump normally cold element. Defrost is accomplished by reversing heat pump polarity, heating the normally cold element. Control mechanisms and logic are provided to automate system operation. In preferred embodiments, dehumidification and defrost modes are activated by a controller monitoring the dew point within the enclosure, and the air pressure at the normally cold element. Dehumidification is performed intermittently, when the enclosure dew point exceeds a set point. Substantially sealing the enclosure against ingress of ambient air reduces the system's operational duty cycle.
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