Patent Application
20070277542
The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:
While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.
HVAC systems according to the present invention have a variety of advantages over conventional systems. Not only do these systems provide for better control of a two-zone or multi-zone space, these systems are less expensive to install than conventional systems. In addition, retrofits of existing systems are also possible by merely adding a damper and a desired number of temperature detecting elements.
A temperature detecting element, also known as a temperature element, is typically a thermocouple or a thermistor. A thermocouple or thermistor may be placed in each zone and wired back to the HVAC controller. More than one thermocouple or thermistor may also be placed in each zone for closer control of the temperature in the zone. It is important to note that in various embodiments of the present invention, these temperature elements need not be thermostats, i.e., they need not be temperature controllers. They are merely detecting elements, detecting a nearby temperature and reporting the temperature to the HVAC controller. If it is desired, remote temperature elements in communication with the controller and not requiring wiring may be used instead. These temperature elements may communicate with the controller via an infrared link or a wireless radio-frequency (RF) link.
The controller receives signals from the temperature sampling devices and uses these signals, a temperature set point, and a control algorithm stored in the controller or in a memory attached to the controller, to automatically turn on heating or cooling from the HVAC system and to adjust the position of the damper. A variety of control algorithms may be used in deciding the position of the damper, and how the damper control is integrated with the furnace/air conditioning controls. For example, the purpose of having a two-zone control is to equalize the temperatures in the zones. That is, the control algorithm may attempt to equalize the temperatures in the zones within a certain range, e.g., ±two degrees F. In one embodiment, if the temperature elements within the two zones are within two degrees of each other, say 70° F. and 72° F., the controller will make no adjustments to the damper.
In this embodiment, the algorithm may be designed so that if the temperature difference is three degrees or more, and the HVAC fan is running, the damper position will adjust a certain amount to route more air to the level requiring additional heating or cooling. The algorithm should be integrated with the control system for the furnace/air conditioner, which will decide whether additional cooling or heating for both zones is required upon reaching a certain differential from the set point. Any desired algorithm, such as a proportional, integral and derivative (PID) algorithm, may be used to control the damper position and thus to adjust the relative temperatures of the zones.
A diagram outlining this HVAC control scheme is depicted in
Embodiments are not limited to the ones already described. For example, if the zones are large, or if one zone is large, more than one temperature element may be located in a zone.
The control algorithm may use the temperatures and the temperature differences in each zone in any desired manner. For instance, the algorithm may average the two temperatures on each floor or zone and make damper adjustments based on the averages. Control over the system temperature may be kept tighter if the algorithm uses the extremes of the temperature differences to adjust damper position. In such an embodiment, there is only one thermostat controlling the temperature set point. The temperature elements in this embodiment are not thermostats and do not independently control a temperature. The control system accepts inputs from a plurality of temperature elements and uses these inputs to calculate whether heating or cooling is required, and also to calculate a desired position of the damper. The control system then activates heating, cooling, or an adjustment of the damper position.
A preferred embodiment of an HVAC system is disclosed in
Embodiments are not limited to two zones. The advantages of the present discovery may be embodied in systems with more than two zones. An example with three zones is depicted schematically in
Furnace plenum 56 is preferably mounted atop furnace 52. First damper 57, mounted atop plenum 56, splits the flow of air between first floor or zone 54a and second and third floors or zones 54b, 54c. Second damper 58 is mounted downstream and further splits the air stream between second and third floors 54b, 54c. The positions of the dampers are controlled by controller 51 using temperature signals received from temperature elements 55a, 55b, 55c located in each of the floors or zones. The position of damper 58 is controlled primarily by the difference between the temperatures of elements 54b, 54c. The position of damper 57 is controlled primarily by the difference between the temperature of element 55a and the remaining temperature elements.
System 50 uses only a single HVAC temperature setting to control multiple zones. System 50 controls the temperature of the multiple zones, automatically balancing the temperatures of the zones, by using at least one temperature element in each zone, and a number of dampers that is equal to the number of zones, less one damper. As noted above, more than one temperature element may be used if the individual zones are large, or if only one zone is large and a closer degree of control over the damper(s) that control the flow of air to that zone.
All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to practicing the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
