Evaporator coil bypass device for HVAC system

Abstract

 It is an object of the present invention to provide 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.

Description

Field of the Invention

[0001] 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.

Background of the invention

[0002] 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.

[0003] 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.

[0004] 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.

[0005] 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. Patent 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. Patent 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.

[0006] 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 invention

[0007] It 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.

Brief Description of the Drawings

[0008] 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.

Figure 1 is a cutaway perspective view of the air-conditioning bypass device according to one embodiment of the present invention; and

Figure 2 is a cutaway side view of the air-conditioning bypass device, according to one embodiment of the present invention.

Detailed Description of the Drawings

[0009] 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.

[0010] With reference to Figure 1 and according to one embodiment of the present invention, the air-conditioning bypass device is positioned on top of a furnace 10 within a residential ventilation system 20 with central air conditioning, around the air-conditioning evaporator coil 30. The evaporator coil 30, with a generally triangular prismatic shape, is located in the path of the air flow, in the main channel 100 of the ventilation system 20. The present embodiment consists of a first and a second bypass diverter 40, 50, extending as a semi-trapezoidal extension from the side of the ventilation system 20, one bypass diverter on either side of the evaporator coil 30. Adjustable doors comprising of a first lower door 62 and a second lower door 64 are pivotally mounted along the lower vertices of the air conditioning coil, to which they are connected by means of a control arms. The control arm 70 is connected to control arm lever 82, which may be manually manipulated to control the flow of air through the evaporator coil 30 and bypass diverters 40, 50, and which are designed so as to lock as each extreme of movement of the first lower door 62 is reached. The control arm lever 82 may be unlocked with operator intervention and the control arm 82 and 94 cannot unintentionally release. The control arm lever 84 controls the second lower door 64 with a control arm (not shown) similar to control arm 70. The first upper door 92 and the second upper door 94 are made of a light material and mounted on piano hinges 95 so that they may easily pivot as a result of airflow. In another embodiment, the first and second upper doors are not present at all. In further embodiments, other means known to persons skilled in the art may be used to prevent the air flow, once having passed the evaporator coil by means of the bypass device, reversing into the air conditioning coil.

[0011] 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.

[0012] 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.

[0013] With further reference to FIGS. 1 and 2, the position of the first lower door 62 and the second lower door 64 is adjusted by means of control arm levers 82 and 84 which project through the wall of the ventilation system 20 and may be adjusted manually or by a motor such that they may be oriented in either summer or winter position. In summer mode the air conditioning is engaged and the evaporating coil is used, so the airflow is directed to flow through the coil. By moving the control arm levers 82 and 84 in an upper motion, the first lower door 62 and the second lower door 64 are positioned so as to close off a first and a second lower bypass diverter ports 105, 110 on either side. This near-vertical position of the first lower door 62 and the second lower door 64 directs the air flow from the furnace 10 through the evaporator coil 30. By the force of the upwardly-channeled air flow, the first upper door 92 and the second door 94 are pushed up, rotating on piano hinges 95, into a vertical position by the airflow to close off a first and a second upper bypass diverter ports 125, 130 on either side, together directing the air through the main channel 100 to be distributed into the building ventilation system.

[0014] With further reference to FIGS. 1 and 2, and according to one embodiment of the present invention, in winter mode the first lower door 62 and the second lower door 64 are adjusted by the operatively connected control arm lever 82 and control arm lever 84 wherein by turning the operatively connected levers 82 and 84 in a downward motion, so that the lower doors are rotated to meet in the middle of the main channel and open the first and second lower bypass diverter ports 105, 110 on either side. Meeting in the middle of the main channel 100, the lower doors together form a "V"-shape, so as to direct the air flow from the furnace into the bypass diverter ports 105, 110, and preventing any air flow from entering the evaporator coil 30 in the main channel 100. The lower doors may form a substantial air flow seal simply by meeting in the middle, or in other embodiments they may have heat-resistant rubber lips which meet, or they may effect a seal using a lip, wherein the first lower door is slightly shorter than the second lower door, and the second door containing a metal folded lip at the end which catches the slightly shorter first lower door. The control arm levers 82 and 84 lock in this lower position, in that they do not release without operator intervention. The air then passes through the first and second bypass diverters 40, 50 after which it re-enters the main channel 100 by means of the first and second upper bypass diverter ports 125, 130. In passing from the first and second upper bypass diverter ports 125, 130 into the main channel 100, the air flow pressure causes the first upper door 92 and the second upper door 94 to be pushed flat on the upper sides of the evaporator coil 30. The first and second upper door 92 and 94, rotating by means of piano hinge 95, is of sufficient size to substantially cover its respective upper side of the evaporator coil 30. The upper doors are also held to the evaporator coil 30 by means of gravity, and prevent air flow out of the upper bypass diverter ports 125, 130 from reversing into the air conditioning coil 30, which is effectively isolated from the air flow by means of the winter position of said upper doors 90. In winter mode, due to the position of the first and second lower doors 62 and 64, there is no airflow through the air conditioning coil, resulting in more efficient air flow throughput as well as lower dust accumulation of the air conditioning coil, reducing the need for cleaning.

[0015] The control arm levers 82 and 84may 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.

[0016] 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

[0017] 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:

i) one or more bypass diverters

ii) 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. A bypass device according to claim 1 further comprising one or more manual control arms operatively connected to the one or more adjustable doors

3. A bypass device according to claim 1 further comprising one or more servo motors operatively connected to the one or more adjustable doors.

4. A 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. A bypass device according to claim 4 wherein the first and second lower door have heat resistant rubber lips.

6. A bypass device according to claim 4 wherein the first lower door is shorter than the second lower door.

7. A 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. A 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. A 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. A bypass device according to claim 4 wherein the bypass diverters have semi-trapezoidal shapes.

11. A 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. A 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.

Drawing