CA2708756C

CA2708756C - Method and kit for passively equalizing air pressures within a house and/or air pressure inside a house with air pressure outside a house

Info

Publication number: CA2708756C
Application number: CA2708756A
Authority: CA
Inventors: Bernie Melanson
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-06-30
Filing date: 2010-06-30
Publication date: 2015-11-24
Anticipated expiration: 2030-06-30
Also published as: CA2708756A1

Abstract

A method equalizes air pressures within a house and/or air pressure inside a house with air pressure outside a house utilizing an auxiliary duct. The auxiliary duct transfers air from a higher pressure area to a lower pressure area causing the two areas of differing pressure to equalize.

Description

METHOD AND KIT FOR PASSIVELY EQUALIZING AIR PRESSURES WITHIN A HOUSE
AND/OR AIR PRESSURE INSIDE A HOUSE WITH AIR PRESSURE OUTSIDE A HOUSE
FIELD OF THE INVENTION
The present invention relates to Heating, Ventilation and Air Conditioning (HVAC) technologies.
In particular, the present invention relates to a method of equalizing air pressures within a house and/or air pressure inside a house with air pressure outside a house utilizing an auxiliary duct connected to an existing exhaust stack of a combustion appliance, such as, for example, a furnace or water heater tank.
BACKGROUND OF THE INVENTION
Generally, a house is heated in cold climates by way of a furnace in which a combustible product, such as, for example, natural gas, oil or wood/coal is combusted in a combustion chamber and the heat produced is moved throughout the house in a number of different ways.
The combustion byproducts escape from the combustion chamber and outside of the home by way of an exhaust pipe connected to a flue or a chimney or the like. To control the combustion rate and ensure efficient combusting conditions in the combustion chamber, secondary air flow is provided to the exhaust pipe by way of a duct that intersects the exhaust pipe having a swinging type damper to control the secondary air flow through the duct.
A phenomenon called "negative pressure" is created in a house that lacks a readily available source of fresh air and is caused by having more air exit the house than is being replenished.
Some of the sources of having too much air exit the house are exhaust fans operating and combustion appliances. Another cause of this phenomenon is from heated air rising in the house and creating a negative pressure on lower levels.
Another cause of negative pressure is the imbalance between inside air pressure and outside air pressure from wind. Wind blowing on the windward side of a house causes a region of positive pressure and a region of negative pressure on the leeward sides parallel to the flow.

In certain situations where the inside pressure of the house drops, for example by the negative pressure phenomenon, or the heat of the combustion byproducts is insufficient to maintain the outward flow of the byproducts through the flue or chimney, it is possible for the flow to reverse and the combustion byproducts be released into the house, this phenomenon is known as "back drafting".
A draft is created in an exhaust stack by the buoyancy of the combustion byproducts, a different draft is created in the house due to the differences in temperature between the air inside the house and the air outside the house. The warmer air inside the house tends to rise since it is less dense and warmer than the air outside the house.
The tendency of the warmer house air to rise results in air pressure differences at various levels in the house. The air pressure in lower levels of the house will be less than the atmospheric pressure. The air pressure in upper levels of the house will be higher than the atmospheric pressure, since the rising air pushes against the ceiling and accumulates. At a certain location between the higher air pressure area and lower air pressure area, the air pressure will be equal to the atmospheric pressure.
The equal atmospheric pressure point is called the "neutral pressure plane".
The variation in air pressure at different levels of the house is called the "stack effect". The taller the house is, the greater the stack effect will be. The stack effect in a house can make a considerable difference in the venting and performance of combustion appliances such as a furnace or water heater tank.
Accordingly, there exists a need for a method of easily and efficiently equalizing air pressures within a house and/or air pressure inside a house with air pressure outside a house and to reduce the effects of the stack effect. Prior art methods and devices have not adequately addressed this problem.
United States Patent No. 4,633,768, issued January 6, 1987 (Benson) discloses a device that comprises a supplemental ventilation apparatus. In one of the embodiments, the invention discloses the ventilation system for a gas burner furnace comprising the conventional central

2 flue for combustion gases release and an inlet air tube which introduces outside air into the furnace.
Canadian Patent No. 1,175,721, issued October 10, 1984 (Newell) discloses a method for increasing the efficiency of a heating system that comprises a furnace, an exhaust pipe to remove the combustion gases extending from the combustion chamber of the furnace to the exterior of the building and an auxiliary duct intersecting the exhaust pipe to permit air to flow from the interior of the building to the exhaust pipe. The flow through the auxiliary duct is controlled in part by a damper and additionally, shut-off valves.
United States Patent No. 4,920,866, issued May 1, 1990 (Hoban) discloses an improved combustion arrangement meant to prevent the back draft in a flue due to the negative pressure in the house. The invention deals with the back draft by adding an additional duct connected to the flue through a nozzle arranged to inject air into the flue in forward direction. Before being injected into the flue, the air is heated and then forced into the flue by a fan.
Canadian Patent No. 681,043, issued February 25, 1964 (Field) discloses a furnace system utilizing separate flue pipes for introducing combustion air and exhausting smoke at the exterior of a building. Field also discloses a cap structure for used at the exterior ends of the flue pipes.
United States Patent No. 4,262,608, issued April 21, 1981 (Jackson) discloses an assembly of powered exhaust flue and preheated combustion air supply for use in association with a heating furnace so that the flue gases are exhausted to the outside while a balanced combustion air supply is pulled inside. The exhaust pipe is concentrically positioned within the outside air intake pipe. Both the exhaust and the air intake pipes are controlled by dampers. The flow of exhaust gases and fresh intake air is controlled by means of fans installed inside the two pipes.

3 SUMMARY OF THE INVENTION
The present invention provides a method of equalizing air pressures within a house and/or air pressure inside a house with air pressure outside a house to reduce the effects of the stack effect utilizing an auxiliary duct connected to the existing flue chimney and intake air from another area. The present invention also provides a kit to perform the method.
As an aspect of the present invention, there is provided a method to install a system for equalizing air pressures within a house. The method comprises the steps of affixing an auxiliary air supply means to an existing exhaust stack of an existing combustion device located in an area with an air pressure that is lower than an atmospheric air pressure and supplying the auxiliary air supply means with air via an aperture located in an area with an air pressure that is equal or higher than the atmospheric air pressure. Preferably, the method comprises the step of controlling an air flow through the auxiliary air supply means by way of a damping means.
As another aspect of the present invention, there is provided a kit for carrying out the method as described above. The kit comprises a series of duct for supplying air via an open end of the series of duct from an area of air pressure that is equal or higher than an atmospheric air pressure, a means for affixing an other end of the series of duct to an existing exhaust stack and a damping means for controlling a flow of air through the series of duct. Preferably, the kit comprises a directional damper for controlling a flow of air through the series of duct.
Also preferable, the kit comprises a one way directional vent for ensuring that air flows only into the open end of the series of duct.
As another aspect of the present invention, there is provided a system for passively equalizing air pressures within a house, the system comprising: a passive auxiliary air supply means affixed to an existing exhaust stack of an existing combustion device located in an area with an air pressure that is lower than an atmospheric air pressure; and a passive aperture located in an area with an air pressure that is equal or higher than the atmospheric air pressure to passively supply the passive auxiliary air supply means with air.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention will be further described, by way of example, with reference to the accompanying drawings, in which:

4 Figures la and lb are perspective views of a standard natural gas fueled furnace and water heater tank;
Figure 2 depicts a house affected by the stack effect; and Figure 3 depicts a house using the method and/or kit according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A better understanding of the present invention and its objects and advantages will become apparent to those skilled in this art from the following detailed description, wherein there is described only the preferred embodiment of the invention, simply by way of illustration of the best mode contemplated for carrying out the invention. As will be realized, the invention is capable of modifications in various obvious respects, all without departing from the scope and spirit of the invention. Accordingly, the description should be regarded as illustrative in nature and not as restrictive.
Figures la and lb show a standard natural gas fueled furnace (1) and water heater tank (2).
Typically, a furnace (1) has a return register (3), a supply register (4), a gas supply line (5), an exhaust stack (6), and a secondary air flow (7). The gas supply line (5) provides fuel for the furnace (1), the fuel combusts in the combustion chamber (not shown) of the furnace (1) and heats the air in a heat exchanger (not shown) that is sucked in from the return register (3), the heated air is then blown out of the supply register to provide heat to rest of the house.
Combustion by products, such as, for example, carbon monoxide, escape from the combustion chamber via the exhaust stack (6).
Similarly, a water heater tank (2) has a cold water inlet (8), a hot water outlet (9), a gas supply line (5), an exhaust stack (6), and a secondary air flow (7). The gas supply line (5) provides fuel for the water heater tank (2), the fuel combusts and heats the water in the water tank (3), the heated water is then available to be used throughout the house. Combustion by products escapes via the exhaust stack (6).

5 Now referring to Figures 2 and 3. The exhaust stack (6) is connected to a flue or chimney (10) which allows combustion byproducts from the furnace (1) or water heater tank (2) to be released through an exterior wall and out of the house. Generally, combustion in the furnace (1) or water heater tank (2) is sufficient to generate an updraft through the flue or chimney (10) so that the combustion gases are drawn away from the furnace (1) or water heater tank (2) to sustain combustion and to ensure that no combustion byproducts remain in the house.
Figure 2 depicts a house (11) having a combustion appliance (12) that is affected by the stack effect. The arrows denote warm inside air rising in the house (11) and the pressure gauges denote relative air pressures in the house (11) and outside the house (11), a clockwise movement of the needle represents a higher relative air pressure and a counter-clockwise movement of the needle represents a lower relative air pressure. As can be seen in figure 2 the upper area of the house (11) has a relative air pressure that is higher than the outside atmospheric pressure and the lower area of the house (11) has a relative air pressure that is lower than the outside atmospheric pressure. At a point between the higher air pressure and the lower air pressure the air pressure inside the house (11) is equal to the outside atmospheric air pressure, i.e. the neutral pressure plane.
Figure 3 depicts a house (13) having a combustion appliance (12) that is using the method and/or kit according to the present invention to reduce the stack effect. As can be seen in figure 3, the air from areas of higher relative pressure (above the neutral pressure plane) is being drawn down into the auxiliary air supply means (14) via an aperture (15) into the areas of lower relative pressure (below the neutral pressure plane). Accordingly, if the air is drawn from upper areas of the house (13), the air pressure in the upper areas of the house (13) is lowered and the air pressure in the lower areas of the house (13) is increased, thus the air pressures in the house (13) are more closely equalized to that of the outside atmospheric pressure and the stack effect is reduced. If the air is drawn from outside the house (13), the air pressure in the lower areas of the house (13) is increased, thus the air pressures in the house (13) are more closely equalized and the stack effect is reduced.

6 The method according to the present invention provides for an auxiliary air supply located inside the house and/or outside the house to reduce the effects of the air pressure variation, i.e. the stack effect, and prevent back drafting, The method broadly comprises the steps of 1) affixing an auxiliary air supply means (14) to an existing exhaust stack (6) of an existing combustion device located in an area of lower relative air pressure (below the neutral pressure plane), (2) supplying the auxiliary air supply means with air from an aperture (15) located in an area of higher relative air pressure (above the neutral pressure plane). Since air located in a higher relative air pressure area will flow freely to an area of lower relative air pressure this will create an escape for the air in the higher relative air pressure are and balance the two different air pressures.
The method according to the present invention may further comprise the step of controlling the air flow through the auxiliary air supply by way of a damping means (16). This ensures that the air can only flow out of the house in one direction and not into the house.
An embodiment of the present invention was installed and tested in a house.
Two 6" aluminum round ducts were connected to the exhaust pipes of a furnace and a water heater tank and sealed with aluminum duct tape, the two aluminum round ducts are connected together with a 6"
aluminum T round duct, the duct was then ran through the house to the uppers levels of the house and into the attic. In general, the attic of a house is vented to the outside and thus will have the same air pressure. The duct was held in place in the ceiling with a duct thimble.
Temperature tests were conducted at various spots on the duct. The outside air temperature was at -15 C. At a point 18" below the ceiling the temperature was measured to be -12 C and at the point where the auxiliary air supply is affixed to the exhaust pipe the temperature was measure to be -0.2 C. This means that the cold air flowing down the auxiliary air supply is warmed up approximately 15 C before it reached the connection point. This shows that air is indeed being drawn down into the lower air pressure areas and is equalizing the air pressure in the house as a result of the fresh air originating from the attic.
A kit is also provided for performing the method as described herein. The kit may broadly comprise adequate duct to reach from an existing exhaust stack to a desired area of higher air

7 pressure, duct tape for sealing the duct, duct insulation, flexible duct, a duct thimble, a vent or a directional vent (17, and a damper.
Optionally the air that is flowing from the area of higher relative air pressure to the area of lower relative air pressure may be outputted into the area of lower relative air pressure. Optionally the air that is flowing from the area of higher relative air pressure to the area of lower relative air pressure may be vented outside the house via the exhaust stack (6), the flue or chimney (10) or outside the house directly.

8

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A system for passively equalizing air pressures within a house, the system comprising:
a passive auxiliary air supply means affixed to an existing exhaust stack of an existing combustion device located in an area with an air pressure that is lower than an atmospheric air pressure; and a passive aperture located in an area with an air pressure that is equal or higher than the atmospheric air pressure to passively supply the passive auxiliary air supply means with air.

2. The system according to claim 1 further comprising a passive damping means for allowing an air flow through the passive auxiliary air supply means.

3. The system according to claim 1 or 2 wherein the passive aperture is located inside the house.

4. The system according to claim 1 or 2 wherein the passive aperture is located outside the house.

5. The system according to any one of claims 1 to 4 wherein the passive auxiliary air supply means are ducts.

6. The system according to any one of claims 2 to 5 wherein the passive damping means is a directional damper.

7. The system according to any one of claims 1 to 6 wherein the passive aperture is a one way directional vent.