AIR CONDITIONING WITH MIXING DUCT

• US 3,823,870 A
• Filed: 12/27/1971
• Issued: 07/16/1974
• Est. Priority Date: 07/14/1970
• Status: Expired due to Term

• Current Assignee: Robert B. Chandler
• Original Assignee: Robert B. Chandler
• Inventors: Chandler, Robert B.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US05/212,593
• Time in Patent Office: 932 Days
• Field of Search: 98/38,4D 236/49
• US Class Current: 236/49.3
• CPC Class Codes: F24F 1/00075 receiving air from a central station
• CPC Class Codes: F24F 1/01 in which secondary air is induced by injector action of the primary air
• CPC Class Codes: F24F 2221/02 combined with lighting fixtures
• CPC Class Codes: F24F 2221/14 mounted on the ceiling
• CPC Class Codes: F24F 3/048 with temperature control at constant rate of air-flow

Abstract

An air conditioning system and method of operating an air conditioning system wherein conditioned primary air is transmitted to a plenum chamber in a terminal unit, which terminal unit may be positioned for example, directly within a space to be conditioned or supported above a suspended ceiling in a space to be conditioned. A portion of the primary air is utilized to pass through nozzles and establish primary air flow in a mixing duct, which flow may induce and mix with a flow of secondary air to constitute supply air for discharge into a space to be conditioned. The supply air may comprise solely primary air or selectively variable volumes of primary air and secondary air, which secondary air may include selectively variable volumes of air recirculated from the space being conditioned and, if appropriate, air from the plenum chamber formed by a suspended ceiling in the space to be conditioned. Additionally, an air handling or terminal unit according to the invention may include a casing connected to a source of primary air for providing a constant flow of primary air and a selectively variable flow of primary air, means for selectively introducing and mixing a flow of secondary air with the constant flow of primary air, the secondary air comprising selectively volumes of recirculated air from the space and, if appropriate, volumes of air drawn from the plenum chamber defined by a suspended ceiling in the space to be conditioned and a control means for controlling the thermal capacity of supply air for the space, the supply air including the primary air from the constant flow and, selectively, volumes of additional or by-pass primary air and secondary air.

Claims

1. In a terminal unit for an air conditioning system for controlling the condition of air in a space comprising:

a. casing means, b. a continuous end to end mixing duct means through said casing means having an inlet for air to be induced from said space and an outlet for delivering supply air from said casing means into said space to be conditioned, c. means on said casing means for connecting said terminal unit to a source of conditioned primary air, d. a primary air plenum in said casing means in communication with the conditioned primary air delivered to said terminal unit, e. said primary air plenum having induction means for introducing a constant relatively small proportion of the conditioned primary air into the mixing duct to induce a flow of air from said space into the inlet of said mixing duct and a flow of supply air from the outlet for said mixing duct into the space to be conditioned, f. by-pass means in said casing means in communication with the conditioned primary air and connected to the mixing duct for delivering a supply of damped conditioned primary air into the mixing air duct at a point spaced from and independent of the induction air delivered by The means to introduce induction air into the mixing duct, g. damper means connected in said by-pass means including, a perforated means and a reciprocable means to uncover varying portions of said perforated means to effect damping of the conditioned primary air and to vary the volume of conditioned air by-passed through said by-pass means, and h. means responsive to changes in the thermal requirements of the space to be conditioned for actuating said damper means to regulate the conditioned primary air to be delivered by said by-pass means into the mixing duct relative the volume of air induced from the space through the inlet to the mixing duct and the conditioned primary air for induction whereby a constant volume of supply air including a ratio of by-pass conditioned air and induced space air is delivered by the terminal unit to provide the necessary thermal capacity for meeting the cooling requirements of the space to be conditioned.

2. In a terminal unit as claimed in claim 1 wherein, a. the by-pass means is operatively connected to the primary air plenum at one end and has an outlet communicating with the mixing duct at the said spaced point, and b. the means responsive to the condition of the air in the space includes, a normally closed damper means disposed in the bypass means, and an actuator for moving said damper means as a function of the variations in the thermal requirements of the space to be conditioned.

3. In a terminal as claimed in claim 2 wherein, a. said casing means has means forming an opening therein to provide communication between the mixing duct and a source of air outside said terminal unit, and b. second damper means operatively associated with the means responsive to changes in thermal conditions of the space to be conditioned and disposed to normally maintain said opening closed whenever conditioned primary air is being by-passed into the mixing duct, c. said second damper means operable in association with the means responsive to uncover the opening to changes in thermal conditions of the space to be conditioned to actuate the opening means for delivery through said opening of varying volumes of outside air relative to the volume of air induced from the space to modulate the temperature of the air from the space and to provide a constant volume of conditioned supply air through said mixing duct outlet including, a ratio of primary air, outside air, and induced space air to obtain the necessary thermal capacity for meeting the heating requirements of the space to be conditioned.

4. In a terminal unit as claimed in claim 3 wherein said second damper means is positioned in the terminal unit to simultaneously and selectively vary the opening of the inlet for the mixing duct and opening for outside air in the casing.

5. In a terminal unit as claimed in claim 3 incuding, a. means mounted adjacent said opening for heating the outisde air which passes through the opening into the mixing duct, and b. means for controlling delivery of heating media to the heating means.

6. In a terminal unit for an air conditioning system for controlling the condition of air in a space comprising:

a. casing means, b. mixing duct means in said casing means having an inlet for air to be induced from said space and an outlet for delivering conditioned supply air from said casing means to said space, c. means in said casing means for connecting said terminal unit to a source of conditioned primary air, d. a primary air plenum in said casing means in communication with conditioned primary air delivered to the casing means having nozzle means for introducing a constant relatively small proportion of the conditioned primary air into the mixing duct to induce a flow of conditioned supply air from said mixing duct through said outlet into the space, e. by-pass means in said casing means in communication with the conditioned primary air delivered to the terminal unit and connected to the mixing duct for delivering a supply of damped conditioned primary air into the mixing duct at a point spaced from and independent of the induction of air delivered by the nozzle means, f. means in said casing providing an opening between said mixing duct and a source of outside air, and g. means responsive to the changes in the thermal requirements of the space to be conditioned to selectively and alternativerly regulate the relative mixture of conditioned by-pass air, the outside air and air from said space entering the mixing duct whereby a constant volume of conditioned supply air is delivered from the mixing duct through said outlet into the space to meet the thermal requirements for selectively and alternatively cooling and heating said space as may be required.

7. In a terminal unit as claimed in claim 6 including, a. means mounted adjacent the means forming the opening in the casing means for heating air passing therethrough, and b. means to control the operation of said heating means.

8. In a terminal unit as claimed in claim 1 wherein, a. the mixing duct is U-shaped in cross-section and forms a space on one side of said casing means in communication with the space to be conditioned, b. the primary air plenum is adjacent the mixing duct to permit the means for introducing induction air to the mixing duct to be disposed medially between the inlet and the outlet for the mixing duct, c. the by-pass means includes, a by-pass chamber, and passage means passing on the side of the primary air plenum remote from the mixing duct, and d. and passage means having an outlet at the point in the mixing duct spaced from the means for introducing induction air into said mixing duct.

9. In a terminal unit as claimed in claim 8 wherein the outlet of the passage means is downstream from the means for introducing induction air into said mixing duct.

10. In a terminal unit as claimed in claim 1 wherein, a. said mixing duct means includes a plurality of spaced passage means, b. each of said spaced passage means having an inlet and an outlet in communication with the space to be conditioned, c. said primary air plenum includes a plurality of spaced primary air plenum sections equivalent to the number of spaced passage means, and each of the spaced sections of the primary air plenum have induction means operatively disposed in a given one of said spaced passage means for inducing a flow of air through said passage means, d. said by-pass means includes a plurality of spaced by-pass passages, each operatively associated with a given one of the spaced passage means of the mixing duct means.

11. In a terminal unit as claimed in claim 10, wherein, a. the spaced passage means include a T-shaped casing forming a plenum means operatively associated with the outlet for each respective passage, b. said casing means has a T-shaped central section housing the portions of the inlet ends of the spaced passage means of the mixing duct means, and the operatively associated primary air plenums and by-pass means therefor, and c. a single damper means is disposed in said T-shaped central casing common to the plurality of spaced by-pass passages.

12. In a terminal unit as claimed in claim 1, wherein, a. the mixing duct means is disposed about the perimeter of the casing means, b. said by-pass means includes an annular convoluted passage disposed inwardly of the primary air plenum, and said convoluted passage has an inlet in communication with said primary air plenum and an outlet in communication with the mixing duct means, c. said means responsive to the condition of the air in the space includes a damper disposed centrally in said casing for operative association with the inlet for the annular convoluted passage to maintain said inlet normally closed, and means for actuating the damper to open said inlet.

13. In a terminal unit as claimed in 12 wherein the outlet for the annular convoluted passage by the by-pass means is disposed to communicate with the spaced point on the mixing duct between the point where the induction air enters the mixing duct and the induced air from the space enters the mixing duct.

14. In a terminal unit as claimed in claim 1, wherein, a. the mixing duct means is disposed about the perimeter of the casing means, b. said by-pass means and said primary air plenums are connected independently of each other to the source of conditioned primary air, c. said by-pass means includes an annular convoluted passage disposed inwardly of the primary air plenum, and said annular convoluted passage has an inlet in communication with the source of conditioned primary air and an outlet in communication with the mixing duct, d. said means responsive to the condition of the air in the space includes, a damper disposed centrally in said casing for operative association with the inlet for the annular convoluted passage, and normally maintain said inlet closed, and means for actuating the damper to open said inlet.

15. In a terminal unit as claimed in claim 14 wherein the outlet for the convoluted passage of the by-pass means is disposed to communicate with a spaced point in the mixing duct between the point where the induction air enters the mixing duct and the induced air from the space enters the mixing duct.

16. In a terminal unit as claimed in claim 14 wherein the mixing duct includes, a. guide vanes, and b. means forming a structure inwardly of the outlet for the mixing duct.