Flexible heat and moisture transfer system

Abstract

A heat and moisture transfer system may include a flexible heat and moisture exchanger in fluid communication with an environment control unit and an enclosed space. The flexible heat and moisture exchanger may include at least one flexible water vapor-permeable membrane, and may be configured to pass air streams simultaneously in different directions in adjacent subchannels formed by the membrane.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Patent Application Ser. No. 61 / 682,232, filed Aug. 11, 2012, which is hereby incorporated by reference.INTRODUCTION[0002]Mechanically heated or cooled and ventilated buildings and other structures require that some portion of fresh make-up air be added continuously to the total volume of circulated air to keep the space fresh, comfortable, and healthy. A corresponding portion of the air which has already been heated or cooled to the desired supply conditions must be exhausted, resulting in a loss of heat energy and a corresponding reduction in the heating or cooling efficiency of the system conditioning the air in the spaces. Heat exchangers are sometimes used in the exhaust air and makeup airflow paths of these systems such that heat is transferred between the two airstreams according to the temperature differential, leaving less cooling or heating to be performed by the mechanical sys...

AI Technical Summary

Benefits of technology

[0006]In a first example, an environmental control system may include an environmental control device having a supply air inlet and a conditioned air outlet in fluid communication with an enclosed space; and a flexible heat and moisture exchanger including a flexible shell enclosing an interior channel, and a flexible, water vapor-permeable barrier disposed within the interior channel, the barrier partitioning the interior channel into a plurality of separate subchannels such that a first subchannel is in fluid communication with an atmosphere external to the enclosed space and with the supply air inlet, and a second, adjacent subchannel is in fluid communication with the external atmosphere and with the enclosed space; wherein the exchanger is configured to receive a supply air stream flowing in a first direction through the first subchannel, and to receive an exhaust air stream flowing simultaneously in a second direction through the second subchannel.

Problems solved by technology

A corresponding portion of the air which has already been heated or cooled to the desired supply conditions must be exhausted, resulting in a loss of heat energy and a corresponding reduction in the heating or cooling efficiency of the system conditioning the air in the spaces.

Good heat exchange is generally possible with these materials, but moisture exchange cannot easily be performed.

However, water absorbed by the paper from condensation, rain, or moisture present in the air can lead to corrosion, deformation, and mildew growth, and, hence, deterioration of the paper exchange film.

The nature of moisture exchange requires a very large surface area in contact with the gas stream, and, consequently, total heat exchangers are often very large in size when compared to heat-only exchangers.

A disadvantage of such porous composite film is that it also permits the exchange of substantial amounts of air between the gas streams, as well as particles, cigarette smoke, cooking odors, harmful fumes, and the like.

From the point of view of building indoor air quality, this is undesirable.

In order to prevent this contamination of make-up air, the pore volume of a porous film is preferably no more than about 15%, which is difficult and expensive to achieve uniformly.

Furthermore, a porous film made to a thickness of 5 to 40 micrometers in order to improve heat exchange efficiency tears easily and is difficult to handle.

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