Evaporator coil bypass device for HVAC System
A bypass device to seasonally bypass an evaporator coil in a building's HVAC system to improve efficiency and reduce dust accumulation. The bypass device comprises one or more bypass diverters around an evaporator coil in an HVAC system, wherein bypass doors may be manipulated so as to close the air path through the evaporator coil and force air to flow through bypass diverters instead. The bypass doors are adjustable using control arms and may be maintained in either a flow-through or bypass position, so as to permit the air flow to travel through the evaporator coil, or bypass the coil, as the operator chooses. The control arms may alternatively be manipulated by a motor and connected to the thermostat so as to automatically select the appropriate position depending on the settings of the thermostat.
This application claims priority of U.S. Provisional Application No. 61/195,162, filed Oct. 3, 2008, under Title 35, United States Code, Section 119(e).
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates generally to HVAC systems and specifically to a bypass device for an air conditioning or evaporator coil in an HVAC system.
2. Description of the Prior Art
In northern climates, residential HVAC systems often employ both central air conditioning and heating. Evaporator coils from the central air conditioning are typically installed in a fixed position in the ventilation system above the furnace. The air is forced through the evaporator coil, causing a considerable amount of drag and static air pressure build-up. This is unavoidable in the summer when the intent is to cool the air. In the winter, however, when residential HVAC systems heat the air passing through, the presence of the evaporator coil in the airstream is unnecessary. The drag and static pressure build-up caused by its presence results in reduced efficiency in two ways: the blower motor must work harder to produce the same throughput, and the air circulation throughout the residence is reduced. This reduced efficiency results in fewer air changes per hour, which increases the rate at which a room's set temperature is reached.
Furthermore, the coil, when cooling in the summer, becomes moist due to condensation and accumulates dust. For optimal performance, the coil must be cleaned approximately every three years, depending on the degree of use the coil sees. If not removed, the dust causes additional drag on the airflow, as well as potentially causing allergies in the building's occupants.
In order to reduce drag of the air passing through the coil during the winter, some homeowners remove the coil from the ventilation system. This can be quite inconvenient, requiring a significant know-how and often the signature of an HVAC professional supervising the work. It can also be dangerous, since the coil may leak as a result of the manipulation thereof, releasing toxic refrigerant gas into the building and atmosphere.
Some inventions intending to maintain a constant air-supply pressure have inserted a bypass and damper between the air supply outlet of the HVAC unit and the return air intake of such a unit to cause a recirculation of a quantity of air which may have been closed off by zone dampers or the like and to approximate a more uniform air supply pressure to the various zones. In much of the prior art, the bypass damper has been controlled by an air pressure sensor, a velocity sensor or a barometric-type sensor associated with the air supply outlet of the HVAC unit. In U.S. Pat. No. 4,487,363, for instance, the bypass damper is modulated according to the current drawn by the fan motor of the HVAC unit. In U.S. Pat. No. 6,085,834 a variable damper is used in order to regulate the volume of air that is to be conditioned, which operates based on the characteristics of the outside ambient air.
The above-mentioned systems are intended to maintain a consistent outflow of air pressure from the system and are not intended to increase efficiency of the system by reducing drag by circumventing the air-conditioning coil. In fact, there has been little attention paid in the prior art to satisfying this need. There is therefore a need for an evaporator coil bypass device to increase efficiency of an HVAC system by reducing drag and static air pressure, and reducing unwanted odors, when the evaporator coil is not in use.
SUMMARY OF THE INVENTIONIt is the object of this invention to provide a bypass to seasonally bypass an evaporator coil in a building's HVAC system to improve efficiency and reduce dust accumulation. The bypass device comprises one or more bypass diverters around an evaporator coil in an HVAC system, wherein one or more adjustable doors may be manipulated so as to close the air path through the evaporator coil and force air to flow through bypass diverters instead. The one or more adjustable doors are adjustable using control arms and may be maintained in either a flow-through or bypass position, so as to permit the air flow to travel through the evaporator coil, or bypass the coil, as the operator chooses. The control arms may alternatively be manipulated by a motor and connected to the thermostat so as to automatically select the appropriate position depending on the settings of the thermostat.
It will now be convenient to describe the invention with particular reference to one embodiment of the present invention. It will be appreciated that the figures relate to one embodiment of the present invention only and are not to be taken as limiting the invention.
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
With reference to
A person skilled in the art would also know that the invention may be implemented using a one or more bypass diverters and a corresponding number of upper doors and lower doors. The bypass diverters 40, 50 are shaped in such a way as to guide the airflow around the evaporator coil without impeding its flow. A person skilled in the art would also know that the bypass diverter may be formed in the semi-trapezoidal shape shown, with or without rounded corners, or as a half-cylinder smoothed shape for facilitating laminar airflow, or any number of other functional shapes.
The position of the first and second lower doors determines which path is taken by the airflow. In summer mode, the airflow is channeled through the evaporator coil, before being distributed through the building ventilation system. In winter mode, the bypass units are engaged so as to divert the air flow around the evaporator coil. Bypassing the evaporator coil in winter has several benefits for the ventilation system: (1) it reduces air drag since the evaporator coil is intended for maximum contact with the through-channeled air, thereby necessarily causing drag on the airflow; (2) the evaporator coil accumulates dust as a result of this surface area, which causes unpleasant odors, and bypassing said coil in the summer reduces these odors.
With further reference to
With further reference to
The control arm levers 82 and 84 may be manipulated manually or may be controlled by a first and a second servo motor, which would be operatively connected with the control arm levers 82 and 84, as would be familiar to one skilled in the relevant art. The motors may further be interconnected with a building's thermostat, so that it automatically chooses the appropriate position for the control arm levers, depending on the thermostat settings. In another embodiment of the present invention, actuators will open the first and second lower doors if a mechanical failure occurs in the servo motors operatively connected to the first and second lower door.
In another embodiment of the present invention, an access door is positioned within the ventilation system in order to allow access to the air conditioning coil and the addition of a control panel would be known by a worker skilled in the relevant art. In another embodiment of the present invention, actuators will open the first and second lower doors if a mechanical failure occurs in the electrical
Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing description and associated drawings. Therefore, it is understood that the invention is not to be limited to the specific embodiment disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.
Claims
1. A bypass device, positioned within a ventilation system having a evaporating coil comprises:
- one or more bypass diverters;
- one or more adjustable doors;
- wherein said doors may be adjusted to divert airflow through the one or more bypass diverters, substantially preventing air flow through the evaporating coil.
2. The bypass device according to claim 1 further comprising one or more manual control arms operatively connected to the one or more adjustable doors
3. The bypass device according to claim 1 further comprising one or more servo motors operatively connected to the one or more adjustable doors.
4. The bypass device according to claim 1 wherein the one or more adjustable doors comprises:
- a first upper door and a second upper door; and
- a first lower door and a second lower door.
5. The bypass device according to claim 4 wherein the first and second lower door have heat resistant rubber lips.
6. The bypass device according to claim 4 wherein the first lower door is shorter than the second lower door.
7. The bypass device according to claim 4 wherein the first and second upper door are gravity operated and the first and second lower doors are manually operated.
8. The bypass device according to claim 4 wherein the first and second upper doors are gravity operated and the first and second lower doors are operated by one or more servo motors operatively connected to a furnace.
9. The bypass device according to claim 4 wherein the first and second upper doors are gravity operated and the first and second lower doors are operated by servo motors operatively connected to a building's thermostat.
10. The bypass device according to claim 4 wherein the bypass diverters have semi-trapezoidal shapes.
11. The bypass device according to claim 4 further comprising a first manual control arm operatively connected to the first lower door and a second manual control arm lever operatively connected to the second lower door.
12. The bypass device according to claim 4 further comprising a first servo motor operatively connected to the first lower door and a second servo motor operatively connected to the second lower door.
Type: Application
Filed: Oct 5, 2009
Publication Date: Apr 22, 2010
Inventor: Sylvain Castagne (Gatineau)
Application Number: 12/587,255
International Classification: F28F 27/02 (20060101); F28F 1/10 (20060101);