This unit relates to an air handling system for a building and, in particular, such a system employing one or more induction units adapted to mix two air flows.
A variety of air handling systems for both large and small buildings are already known in the air handling industry. Air handling systems both for residential and commercial buildings can include the use of a central heating system that includes a fan unit capable of blowing heated air through air ducts that deliver the air to the various rooms of the building. When this system is used in conjunction with a central air conditioner, it is also capable of providing cool air to the various rooms through the air ducts. A relatively large fan is generally required for a large commercial or industrial building. Air silencers can be installed on both the inlet side and outlet side of these large fans to reduce the noise levels created by the operation of such fans.
It is also known to provide so called induction units that employ the venturi effect to mix together both return air from a building and primary air. The two air flows are mixed in a mixing chamber located adjacent an elongate air plenum with a primary air inlet at one end. Tapered nozzles extend into the mixing chamber and are connected to a wall of the air plenum. The return air from serviced space enters the mixing chamber which is flanked by the induction unit""s coils on one side and the other sides of the enclosure of the unit. There is an opening on the heat exchanger side of the enclosure for entry of the return air. These units can typically be mounted on a wall of a room with the air plenum section located near the floor and the air outlet located at the top of the unit. Such induction units have at least several advantages including the ability to operate at very low noise levels since they do not employ any fans or similar air circulating devices. They can also be used in conjunction with both high pressure as well as low pressure air duct systems and they provide for a reasonably efficient mixing of the primary air and the return air.
Systems for delivering treated air to a room through an outlet located in the ceiling are already known. For example, U.S. Pat. No. 4,672,887 which issued Jun. 16, 1987 to Fred Sproul Sr. describes an air delivery system located above a horizontal ceiling in a dwelling. The air duct system delivers treated air to a valance/diffuser air system that can be located adjacent one wall of the dwelling. The conditioned or treated air is forced into the air delivery system by a blower of a conditioning unit such as a forced air furnace. At the wall the air is initially distributed lengthwise along an elongate horizontal chamber and then distributed through apertures in a downwardly direction. However, this known system does not use air induction units for mixing return air and primary air. In this known system the return air system is located beneath the floor of the dwelling.
More recent U.S. Pat. No. 5,577,958 issued to Mitsubishi Denki Kabushiki Kaisha in November, 1996 describes a ceiling-embedded cassette type air conditioner located above a decorative grate or panel through which return air can pass. A blower is located centrally in this air conditioner and it forces the return air through two or more heat exchangers located on the perimeter of the blower. The conditioned air is returned to the room through two or more outlets located at the ceiling level. Air directing plates can be positioned in the air outlets and these can direct the outflowing air to flow into the room at an angle to the horizontal. This known air conditioning system does not employ any induction unit that relies on the venturi effect and, because it employs a blower, it will be quite noisy when it is operating.
In commonly assigned U.S. Pat. No. 6,213,867 issued Apr. 10, 2001, there is described a venturi type air distribution system which is designed to be mounted in a ceiling of a room. In this known system, there are two induction units each of which has an air mixing section forming an air mixing chamber and an air plenum section mounted at an upper end of the air mixing section. Air nozzles extend into the air mixing chamber and are mounted on a side of the air plenum section. The air mixing section has an air outlet in the form of a slot formed at a lower end thereof and a side air inlet for permitting return air to flow through a side of the air mixing section. These two induction units are mounted so that each air mixing section extends at a substantial acute angle, such as an angle of about 45 degrees, to the ceiling during use of the system. With the use of these two units, the return air is drawn by a venturi effect created by the nozzles into each air mixing chamber and the two units are capable of delivering a mixture of primary air and return air through the air outlets to the enclosed space.
It is an object of the present invention to provide an improved air handling system for a building which employs four induction units forming a rectangular induction unit assembly and which is capable of mixing return air and primary air efficiently and quietly.
It is a further object of the present invention to provide an improved air handling apparatus for a building which comprises four induction units forming a rectangular or square assembly, can be manufactured and installed at a reasonable cost, and can be operated and maintained at a low cost.
According to one aspect of the invention, an air handling system for a building having a horizontally extending ceiling and an enclosed space comprises an induction unit assembly having four induction units for mounting adjacent the ceiling. Each of these units has an air mixing section forming a relatively long air mixing chamber, and an elongate horizontal extending air plenum section mounted adjacent an upper end of the air mixing chamber and having a primary air inlet formed therein, and air nozzles extending into the air mixing chamber and mounted on an upper side of the air mixing section. The air nozzles each have an inlet end located at the upper side and adapted to receive primary air from the air plenum section. The air mixing section has an air outlet formed at a lower end thereof and a side air inlet for permitting air to flow through a side of the air mixing section and into the air mixing chamber. The induction unit assembly is substantially rectangular or square in plan view. Each of the induction units is located on a respective one of the four sides of the assembly. Supporting members are provided to mount the induction units so that each air mixing section is located adjacent the ceiling during use of the system in the building. Also during use of this system, the return air is drawn by venturi effect created by the nozzles into each air mixing chamber. The induction units are capable of delivering a mixture of primary air, that passes through their plenum sections and the nozzles, and return air through the air outlets to the enclosed air space.
Preferably a heat exchanging coil unit is mounted adjacent to the side of each air mixing section so that the return air flowing through each side air inlet first passes through the respective coil unit in order to be heated or cooled thereby.
According to another aspect of the invention an air handling apparatus for a building having enclosed space includes four induction units adapted for mounting in a ceiling of the enclosed space and forming four sides of an induction unit assembly which is substantially rectangular or square in plan view. Each induction unit includes an air plenum section with a primary air inlet, an air mixing section connected to the air plenum section and forming an air mixing chamber which in transverse, vertical cross-section is elongate, and a series of air nozzles mounted on one side of the air mixing section and extending into the air mixing chamber. Each air mixing section has an air outlet in an end thereof spaced from the air plenum section and a side air inlet for permitting return air to flow through a side of the air mixing section in the region of the nozzles. Supporting members are provided to mount the induction unit assembly at or near the ceiling so that each air mixing section as seen in transverse, vertical cross-section extends at an angle of about 90 degrees to the ceiling during the use of the apparatus. Also, during use of this apparatus, the return air is drawn by venturi effect created by a fast flow of primary air from the nozzles into each air mixing chamber. The induction units are capable of providing air flows comprising a mixture of the primary air and return air at the air outlets.
According to still another aspect of the invention, an air handling system for a building having a ceiling and an enclosed space below the ceiling includes four induction units adapted for mounting adjacent the ceiling and forming four sides of an induction unit assembly which is substantially rectangular in plan view. Each of these units has a primary air intake section and an air mixing section that, during use of the system and when viewed in transverse, vertical cross-section extends downwardly at an angle of approximately 90 degrees to the ceiling to an air outlet formed at the lower end of the air mixing section. Each air mixing section also has a side air inlet for permitting return air to flow through a side thereof into an air mixing chamber of the induction unit. Supporting members are also provided for mounting the rectangular induction unit assembly so that the assembly is located adjacent the ceiling during use of the system in the building. During use of this system, the return air is drawn by a venturi effect into each air mixing chamber and the induction units are capable of delivering a mixture of primary air, taken from the primary air intake section, and return air through the air outlets to the enclosed space.
In one preferred embodiment, each primary air intake section comprises an elongate, horizontally extending air plenum mounted at an upper end of the air mixing chamber and having a primary air inlet formed in one end thereof.
According to yet another aspect of the invention, the invention comprises the combination of a building structure having an enclosed space and an air handling system capable of providing a mixture of primary air and return air to this enclosed space. The combination comprises a horizontal extending ceiling and walls forming the building structure and defining the enclosed space and four air induction units mounted adjacent the ceiling and forming an induction unit assembly which is substantially rectangular in plan view with each induction unit located on a respective side of the rectangle. Each induction unit has a primary air intake section and an air mixing section that, as seen in transverse cross-section, extends downwardly at an angle of about 90 degrees to the ceiling to an air outlet formed at a lower end of the air mixing section. Each air mixing section also has a side air inlet for permitting return air to flow through a side thereof into an air mixing chamber of the induction unit. Supporting frame members mount the induction units adjacent the ceiling. During use of this system, the return air from the enclosed space is drawn by a venturi effect created by each induction unit into the air mixing chambers and the four induction units deliver the mixture of primary air and return air through the air outlets to the enclosed space.
In one preferred embodiment, the induction units are about equal in size and the induction unit assembly is square in plan view.