Ventilation – Having inlet airway – Including automatic control means
Reexamination Certificate
2000-03-06
2001-09-04
Joyce, Harold (Department: 3749)
Ventilation
Having inlet airway
Including automatic control means
C454S255000, C454S239000
Reexamination Certificate
active
06283851
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to make-up air equipment. More specifically, this invention relates to equipment which provides make-up air and the control of such equipment.
Make-up air equipment supplies additional outside air to a building space. Make-up air is needed when an exhaust producing appliance within the building is operated. This make-up air equipment keeps the building from becoming depressurized. If depressurization of the building occurs, potentially dangerous situations may exist. Most importantly, spillage and back drafting of combustion by-products can occur—a very hazardous situation. This is generally true of all fossil fuel appliances like furnaces, water heaters, and wood burning equipment, etc.
In addition to the potentially hazardous situation mentioned above, an imbalance between the indoor and outdoor pressure can create uncomfortable conditions for the building occupants and can negatively impact the building structure. As is well known, air will move from spaces with a higher pressure to spaces with a lower pressure. Small openings in the building envelope allow for air to move through the wall to the lower pressure side. Depending on the indoor and outdoor temperature and dew point conditions, this may lead to condensation occurring within the wall and eventually to a degradation of the building structure. Imbalanced air pressures can also make doors and windows difficult to open and close and, in some cases prevent them from being held open or closed as desired. Consequently, it is desirable to utilize appropriate equipment to maintain indoor pressure equal to outdoor pressure.
Make-up air equipment generally consists of a fan and damper arrangement, sometimes utilizing a heater to condition outdoor air prior to delivery indoors. However, a control system does not presently exist for automatically adjusting the amount of make-up air to maintain neutral indoor air pressure (relative to outdoors). As a result, make-up air systems typically are manually controlled by simply turning a switch on or off. Such systems are often not turned on when needed, and do not respond to variable demand when, for example, multiple exhausting devices are used simultaneously. Other present make-up air systems may be interlocked with exhausting devices, but still lack the ability to respond to variable demand.
SUMMARY OF THE INVENTION
The invention is directed to providing a system and method for optimizing the control of makeup air systems. The invention would allow balanced airflow rates; namely the make up air volume brought inside the building would substantially equal the air volume exhausted from the building.
A control system for a make-up air apparatus (use in a controlled building space) includes a first sensor for sensing the operation of a first appliance within a building space. The appliance, when operational, causes air to be exhausted from the controlled building space. The first sensor for the make-up air apparatus communicates a first signal to a controller when the first appliance is activated. The controller can then use this information to control a make-up apparatus. A link allows the controller to render the make-up air apparatus operational when appropriate.
The control system monitors the air flow requirements between the controlled building space and an environment outside of the controlled building space such as to ensure a predetermined balance of the pressure of air within the controlled building space and the environment outside of the controlled building space. These airflow requirements are determined by monitoring each appliance within the controlled space which causes air to be exhausted. The make-up air apparatus includes a blower, a back-flow damper and a preheater to provide make-up air when necessary. Further, an air temperature monitor senses the outside air temperature and the preheater is activated at a predetermined temperature. A power supply activates a blower motor within the make-up air apparatus causing a blower to draw air into the building space. The motor speed and preheater operation is determined in response to at least one of the temperature data monitor and/or the pressure imbalance caused by the operation of at least one exhaust producing appliance.
In a preferred form of the invention there is a second sensor associated with a second appliance. The controller receives a second signal from the second sensor when the second appliance is operational. This indicates that the second appliance is withdrawing air from the controlled space. This information allows the control system to appropriately account for the effects of both the first and second appliance. Additionally, multiple sensors could be incorporated into the system, depending upon the number of exhaust producing appliances within the controlled space.
The appropriate motor speed is continually determined and adjusted, thereby adjusting the blower to regulate intake of air into the controlled building space. When an exhaust producing appliance is deactivated, a sensor associated with the appliance sends a signal to the control system. When all of the exhaust producing appliances within the controlled space are deactivated, the control system will deactivate the blower and preheater and close the back-flow damper. Alternatively, if at least one of the exhaust producing appliances continued to be operational, the make-up air apparatus would continue to operate.
In one form, the appliance is hardwired to the control system allowing the appliance to directly signal the control system regarding its operation. In another form a remote sensor such as a current sensor relay is used to determine the operational condition of the appliance. In this embodiment, the sensor is connected to the control system and is responsible for sending appropriate signals. In yet another form a wireless sensor is used. In this configuration, these wireless sensors (e.g. radio frequency (rf.) sensors) produce signals indicative of the appliance operation and relay these signals between an appliance and the control system.
It is the object of the present invention to provide control of make-up air by monitoring the operation of all exhaust producing appliances within a controlled space. This monitoring then allows control of the make-up air apparatus in order to provide a pressure balance in the controlled space.
It is a further object of the present invention to monitor the operation of a plurality of exhaust producing devices and appropriately control the make-up air system to react to variable levels of exhaust. That is, it is an object of the present invention to control make-up air in response to the operation of multiple exhaust producing devices, which will produce variable levels of exhaust.
The foregoing and other objects, features, and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments which makes reference to several drawing figures.
REFERENCES:
patent: 4401261 (1983-08-01), Brown
patent: 4773311 (1988-09-01), Sharp
patent: 5131887 (1992-07-01), Traudt
patent: 5462485 (1995-10-01), Kinkead
patent: 5720658 (1998-02-01), Belusa
patent: 5846128 (1998-12-01), Kramer
Kensok Timothy John
Smith Timothy John
Terlson Brad Alan
Boles Derek S.
Honeywell International , Inc.
Joyce Harold
Leonard Robert B.
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