Plate-type heat exchanger

#This invention relates to a plate-type exchanger and more particularly, to a plate-type heat exchanger wherein the plates comprise a polymer membrane having enhanced moisture transfer properties.

#Heating, ventilation and air conditioning (HVAC) systems typically recirculate air, exhaust a portion of the re-circulating air, and simultaneously replace such exhaust air with fresh air. In order to maintain an air temperature and humidity level within a certain space at or near a set point, it is desirable to condition the fresh air the temperature and humidity level set point. Unfortunately, the temperature and humidity of fresh air often differ substantially from those of the set points. For example, during hot and humid periods, such as the summer months, the incoming fresh air typically has a higher temperature and/or humidity level than desired. Additionally, during cold and/or dry periods, such as the winter months, the incoming fresh air typically has a lower temperature and humidity level than desired. The HVAC system must, therefore, condition the fresh air before introducing it to the room.

#HVAC systems are typically designed according to the worst climatic conditions for the geographic area in which the HVAC system will be located. Such worst case climatic conditions are referred to as a cooling and heating “design day.” Conditioning the fresh air during such extreme climatic conditions creates a significant load on the HVAC system. System designers, therefore, typically design the HVAC system with sufficient capacity to maintain the set point during the design day conditions. In order to create the required capacity, the HVAC system may include oversized equipment. Alternatively, as discussed in U.S. Pat. No. 4,051,898, which is hereby incorporated by reference, in order to reduce the load on the HVAC system, system designers often incorporate ventilators within the HVAC system. Reducing the ventilation load on the HVAC system decreases its capacity requirements, which, in turn, allows the designers to specify smaller sized equipment, thereby leading to a more efficient design.

#FIG. 1 illustrates a ventilator comprising a prior art plate-type heat exchanger having a plurality of alternating counter flow passageways therein.

#FIG. 2 illustrates a plurality of ionomer membrane plates for constructing a plate-type heat exchanger.

#FIG. 3 illustrates the plurality of ionomer membrane plates illustrated in FIG. 2 along with spacer bars located along two sides of each plate for spacing apart the plates and sealing the passageways therebetween.

#Referring to FIG. 2, there is shown a plurality of plates 20 spaced apart from one another to form passageways (i.e., gaps or spaces) between the plates 20. The plates 20 are constructed of an ionomer membrane, which has a high moisture transfer characteristic. An ionomer membrane shall mean a membrane composed of an ion containing polymer, such as a sulfonated polymer membrane or a carboxylated polymer membrane that is capable of transferring moisture from one of its sides to the other. A sulfonated polymer membrane shall mean a layer of polymer comprising a sulfonated ion (SO3−/+) within its chemical structure. The sulfonated ion (SO3−/+) is typically located within the side chain of a polymer having a perfluoronated or hydrocarbon backbone structure. Examples of a generic chemical structure for a sulfonated polymer membrane comprising a perfluoronated backbone chemical structure includes the following:

#wherein, m and n are comparable variables;

#Moreover, examples of commercially available sulfonated polymer membranes having a perfluoronated chemical structure include those membranes manufactured by W. L. Gore & Associates, Inc., of Elkton, Md. and distributed under the tradename GORE-SELECT and those perfluoronated membranes manufactured by E. I. du Pont de Nemours and Company and distributed under the tradename NAFION.