Heat exchange – With timer – programmer – time delay – or condition responsive... – Having heating and cooling capability
Reexamination Certificate
2001-11-05
2004-04-27
Ford, John K. (Department: 3743)
Heat exchange
With timer, programmer, time delay, or condition responsive...
Having heating and cooling capability
C165S211000, C165S216000, C165S217000, C165S244000, C236S049300, C236S00100H, C236S00100H
Reexamination Certificate
active
06725914
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to HVAC (heating, ventilating and air conditioning) systems, and more particularly relates to systems and methods for delivering air to areas of a building by the use of a dual duct system which converts to a multiple zoned single duct system at the delivery end.
2. Background Information
There are a number of ways of heating rooms within a commercial building, but one method currently in use is the use of a double duct system. In a double duct system, one duct delivers cool air from a cool air source such as an air conditioning unit, and another duct delivers warm air from a heater. The two ducts are routed to each room or heating and cooling zone of a building. At the room or heating and cooling zone, the cool air and warm air are mixed according to the temperature needs of that specific room or zone. Thus, each room or zone has two ducts delivered into a mixing chamber, and it also has two dampers which open and close both ducts to deliver the right amount of hot and cold air to achieve the desired temperature of air for delivery to the room or zone. A computer can be utilized and a method called variable air volume (VAV) can be utilized so that each room gets the desired volume and temperature of air it requires, and the temperature of the cold air and the hot air is adjusted to best meet the needs of all of the rooms.
A disadvantage of a conventional dual duct system is that it is expensive to install, because two complete ducting systems must be delivered to each room or zone to be heated or cooled, and two computer controlled VAV dampers are required in each room or zone to be heated and cooled. If similar performance could be achieved while having only one duct routed to each room or zone, then significant savings could be achieved in the cost of ducting, dampers, mixing chambers and the labor involved in installation. Energy savings could be achieved in a system in which the conditioned air is generally not mixed from hot or cold air.
SUMMARY OF THE INVENTION
The invention is a double duct changeover HVAC system, which provides a simple, and effective means for economically controlling the temperature and air flow in buildings. The system utilizes two conditioned air sources. In one configuration of the system, one conditioned air source provides warm air, and the other conditioned air source provides cool air. Certain advantages are achieved if one or both of the conditioned air sources also have the ability to produce hot or cold air depending upon the demands of the heating and cooling zones. Air from the first and second conditioned air source is blown by a fan into a first and second main duct system. However, unlike the prior art, these two duct systems, which typically would contain air of different temperatures, are not ducted directly into each room or heating and cooling zone. In this description, it is to be understood that a room is a heating and cooling zone, but several rooms can also make up a single heating and cooling zone. When a “room” is referred to, what is meant is a heating and cooling zone.
In one configuration of the invention, a building or floor to be heated is divided into exterior exposures. This would typically be four exterior exposures, representing the four sides of the building, but more than four exterior exposures are also possible if certain areas of the building experienced unique sun or wind exposure. In general, all of the heating and cooling zones or rooms within a particular exterior exposure would be subjected to similar exposure to the sun, shade of the building, wind exposure and other exterior environmental factors. For instance, all of the heating and cooling zones on a north facing side of building would be in one exterior exposure, and they would generally be subjected to similar sun exposure and heat loss. Similarly, all the rooms or heating and cooling zones on the south side of a building could also be in the same exterior exposure. Those rooms would be expected to have similar exposure to sun and heat loss to each other, but could be quite different from the environmental conditions found on the north facing exterior exposure.
In the double duct changeover HVAC system of the invention, air from the first conditioned source and the second conditioned air source is available for each exterior exposure. This can be by ducting branches of the first and second main duct system extending toward each of the four exterior exposures of the typical installation. At some point, near the edge of a particular exterior exposure, the ducts of the first main duct system and the second main duct system would terminate in a Y or T connection and proceed from that point as a single duct. Air through this single duct would be distributed to each of the heating and cooling zones of that particular exterior exposure. Exterior exposure dampers are present in each terminus of the first main duct system and the second main duct system. The exterior exposure dampers variably open or close to regulate the air flowing from each of the first main duct system and the second main duct system, and to control the temperature of air delivered to each room.
However, the individual heating and cooling zones within the exterior exposure would also inevitably have different air flow quantity needs. Achieving the right temperature in any particular heating and cooling zone, when air of a uniform temperature is delivered to each of the exterior exposures, can be accomplished by the system of the invention.
Each of the heating and cooling zones have a sensor for determining the air flow into the room or heating and cooling zone, and the temperature of the room or heating and cooling zone. Based upon the heating and cooling needs of each room, a damper at each room would open or close to deliver the right volume of air to each room to achieve the desired temperature and airflow. The temperature of air to be delivered to each exterior exposure would be determined by a sampling of all of the temperature sensing devices from each of the rooms of the exterior exposure. A value would be arrived at by calculation in a computer, and the selected temperature of air would be mixed at the exterior exposure dampers of each exterior exposure. The volume of that air would be calculated by the computer, and each heating and cooling zone damper would variably open to admit the calculated volume of the air from the distribution duct system into each room.
It is possible that the heating and cooling needs of one particular room of an exterior exposure would have incompatible needs from the other rooms of that exposure. For instance, one room could need cool air, while the other eight rooms needed hot air. In such a circumstance, the computer would sample all of the temperature sensing sites and determine the needs for all of the sites. When an incompatibility is detected, the computer calculates a split delivery schedule of air to rooms with conflicting needs. For instance, for a period of time, the exterior exposure dampers of one exterior exposure would mix air so that heated air goes to the eight rooms which need heated air. During that time, the zone damper in the room which needed cool air would close or go to a minimum setting, and a minimum or none of the warm air would be delivered to that room. After a period of time, the computer would change the mix of hot and cold air at the exterior exposure dampers for the exterior exposure, and send cool air into the distribution duct system for that exterior exposure. At the same time, the heating and cooling zone dampers for the rooms which needed warm air would close or go to a minimum setting, the zone damper for the rooms needing cold air would open, and the cool air would only go to the room which needed cool air. If several rooms needed cool air, each of their heating and cooling zone dampers would adjust to deliver the right amount of cool air to each one to achieve the proper temperature. After a period of time, the heating
Dykas Frank J.
Ford John K.
Nipper Stephen M.
Shaver Robert L.
LandOfFree
Double duct changeover HVAC system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Double duct changeover HVAC system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Double duct changeover HVAC system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3269770