Pressure Sensitive Bypass Defrost System

a bypass defrost and pressure-sensitive technology, which is applied in the field of defrost arrangement of air exchange ventilators, can solve the problems of increasing pressure drop and building up, and achieve the effects of limiting the depressurization effect, increasing pressure drop, and maintaining the heating capacity of the heat exchanger

US20070084586A1Inactive Publication Date: 2007-04-19IMPERIAL SHEET METAL
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Patent Information

Authority / Receiving Office
US · United States
Patent Type
Applications(United States)
Current Assignee / Owner
Publication Date
2007-04-19
Estimated Expiration
Not applicable · inactive patent

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Abstract

A heat recovery ventilator defrost system utilizing a bypass section which supplies warm air in both channels of the heat exchanger to accelerate defrost, continue some ventilation of stale warm air, and recirculate a portion of the stale air flow, so as to warm incoming cold fresh air. When the system is in defrost mode, warm exhaust air to be expelled enters an exhaust inlet port and into an exhaust plenum. Because the air being exhausted (by way of the exhaust fan) through the exhaust plenum is under a positive pressure, the stale air will still be sucked out through exhaust passageway into discharge plenum, but also through the passive non-motorized bypass section into inlet plenum. Further, because fresh air continues to be drawn into inlet plenum, due to the positive pressure, the warm stale air which has passed through the bypass section (flap) into inlet plenum is then drawn through the heat exchanger along the inlet passageway into supply plenum, and out through supply port into the enclosure or dwelling. In this way, the heat recovery ventilators defrost system of the present invention supplies warm air in both channels of the heat exchanger.
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Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to air exchange ventilators for admitting fresh air into an enclosure while exhausting stale air. More particularly, this invention relates to a defrost arrangement for air exchange ventilators which include a heat exchanger to extract heat from the stale air and transfer it to the incoming fresh air, and which introduces warm air in both channels of the heat exchanger to accelerate defrost, continue some ventilation of stale warm air, and recirculate a portion of the stale air flow at mild temperatures as opposed to the lower temperatures of incoming fresh air.

[0003] 2. Description of the Related Art

[0004] Highly energy efficient buildings are generally designed to avoid uncontrolled intake and out-take of air. As some air exchange is necessary to remove stale air and replace it with fresh air, it is desirable in winter to first remove heat and or energy from the stale air and replace it wi...

Examples

Embodiment Construction

[0028] The present invention provides a defrost arrangement for air exchange ventilators which includes a heat exchanger to extract heat from the stale air and transfer it to the incoming fresh air, and which introduces warm air in both channels of the heat exchanger to accelerate defrost, continue some ventilation of stale warm air, and recirculate a portion of the stale air flow at mild temperatures as opposed to the lower temperatures of incoming fresh air. In conventional systems, during the defrost mode the fresh air motor shuts off, and warm stale air is used to defrost the heat exchanger. This air is then totally expelled outdoors which can contributes to the depressurization within the dwelling or building. With reference to FIGS. 1 and 4, incoming fresh air is admitted into the air exchange system at (2) to flow through an inlet passageway (4), which is then passed through the heat exchanger (6), to flow (8) into an enclosure. Exhaust air to be discharged from the enclosure...