Variable air volume air conditioning system

• US 4,540,118 A
• Filed: 04/11/1984
• Issued: 09/10/1985
• Est. Priority Date: 04/11/1984
• Status: Expired due to Fees

• Current Assignee: R J Reynolds Tobacco Company (R. J. Reynolds Tobacco)
• Original Assignee: R J Reynolds Tobacco Company (R. J. Reynolds Tobacco)
• Inventors: Lortie, Richard P., Adams, William R.
• Primary Examiner(s): Bennett, Henry
• Application Number:
  US06/599,074
• Time in Patent Office: 517 Days
• Field of Search: 236/44, 236/44 C, 236/44 R, 62/176.4, 62/171, 62/309, 165/19, 261/DIG. 34, 261/26, 261/28
• US Class Current: 236/44.00C
• CPC Class Codes: F24F 2011/0006 using low temperature external supply air to assist cooling
• CPC Class Codes: F24F 3/0442 with volume control at a constant temperature
• CPC Class Codes: F24F 3/153 with subsequent heating, i.e. with the air, given the required humidity in the central station, passing a heating element to achieve the required temperature
• CPC Class Codes: Y10S 261/34 Automatic humidity regulation

Abstract

A variable air volume air conditioning system is disclosed which is capable of accurately controlling temperature and humidity levels in a conditional zone while achieving significant economy of operation.

Claims

1. A variable air volume air conditioning system for maintaining a conditioned zone at predetermined temperature and humidity levels comprising in combination

(a) a chamber having an entrance end provided with separate modulated damper means for admitting outside air and return air into the chamber and an exit end for delivering conditioned air to a supply air duct carrying conditioned air to said conditioned zone,

(b) spray means positioned within the chamber intermediate the entrance and exit ends for spraying sufficient quantities of water into air moving through said chamber to deliver conditioned air to the supply air duct that is substantially saturated with water vapor and is adjusted to a predetermined temperature,

(c) moisture eliminator means positioned within the chamber intermediate the spray means and said exit end for removing droplets of water entrained in the conditioned air,

(d) variable capacity fan means for moving controlled volumes of air through said system per unit of time,

(e) sensing means for monitoring the dew point of the conditioned air delivered to the supply air duct and control means associated therewith for modulating the damper means which admit outside air and return air into the chamber,

(f) modulated supply air damper means located at the terminus of the supply air duct for admitting conditioned air into said conditioned zone,

(g) heating means disposed in the supply air duct adjacent to the supply air damper means for heating the conditioned air,

(h) temperature sensing means located in the conditioned zone and control means associated therewith for regulating said heating means and modulating said supply air damper means in response to temperature changes in said conditioned zone, and

(i) pressure sensing means located in the supply air duct and control means associated therewith for modulating the capacity of said variable capacity fan and for regulating the quantity of water injected into the air by said spray means as the air moves through said chamber.

2. The system of claim 1 wherein said chamber is provided with a sump in which a plurality of water is maintained for supplying water to said spray means and in which excess spray water is collected, said sump being provided with means for heating and cooling the quantity of water maintained therein.

3. The system of claim 2 wherein the sensing means for monitoring the dew point of the conditioned air comprises a temperature sensor positioned in the quantity of water maintained in the sump and control means associated with said temperature sensor for regulating the means for heating and cooling the quantity of water in the sump and for modulating the separate damper means which admit outside air and return air into the chamber.

4. The system of claim 2 wherein the sensing means for monitoring the dew point of the conditioned air comprises an absolute humidity sensing device adapted to sample continuously the conditioned air delivered to the supply air duct and control means associated with said humidity sensing device for regulating the means for heating and cooling the quantity of water in the sump and for modulating the separate damper means which admit outside air and return air into the chamber.

5. The system of claim 2 wherein said spray means includes at least two spray nozzle assemblies, separate spray water pumps delivering water to each of said spray nozzle assemblies and control means which provide for operation of only one of the spray water pumps and its associated spray water assembly during periods of low demand on the system.

6. The system of claim 2 wherein said chamber is provided with a baffle plate positioned in the path of the air moving through the chamber, the location of said baffle plate being immediately upstream of said spray means.

7. The system of claim 1, 2, 3, 4, 5 or 6 wherein the supply air duct is provided with a plurality of terminuses for delivering conditioned air to a plurality of conditioned zones, each of said terminuses having a modulated supply air damper means associated therewith which is responsive to a temperature controller and temperature sensing means located in the conditioned zone.

8. The system of claim 7 wherein at least one of said terminuses is provided with heating means, said heating means being disposed within the supply air duct downstream of said supply air damper means.

9. The system of claim 7 wherein said temperature controller possesses proportional with integral or integral with derivative control capabilities.

10. A method for controlling at predetermined levels the temperature and humidity of air in a conditioned zone comprising the steps of

(a) establishing a flow of air through an air treating system that delivers conditioned air to the conditioned zone, said system including an air washer, a supply air duct and a variable capacity fan for moving variable volumes of air through the system per unit of time,

(b) spraying a controlled quantity of water into the air as it moves through the air washer to produce a stream of conditioned air that is substantially saturated with water vapor,

(c) controlling the dew point temperature of the conditioned air leaving the air washer by regulating the flow of return air withdrawn from the conditioned zone and outside air into the air washer and by adjusting the temperature of the water sprayed into the moving air,

(d) controlling the flow and heating of conditioned air passing from the supply air duct into the conditioned zone in response to signals from a temperature sensing device located in the conditioned zone,

(e) varying the quantity of water sprayed into the moving air and the volume of air moving through the system per unit of time in response to signals from a pressure sensing device disposed in the supply air duct.

11. The method of claim 10 wherein the dew point temperature of the conditioned air leaving the air washer is controlled by a temperature sensor and controller which maintains the temperature of the water sprayed into the moving air at predetermined levels.

12. The method of claim 10 wherein the dew point temperature of the conditioned air leaving the air washer is controlled by a device which monitors the absolute humidity of the conditioned air delivered to the supply air duct.

13. The method of claim 10, 11 or 12 wherein the conditioned air passing through the supply air duct is directed through a plurality of terminuses into a plurality of conditioned zones in response to signals from a temperature sensing device located in each of said conditioned zones.

14. The method of claim 13 wherein the conditioned air directed through at least one of said terminuses is heated in response to signals from a temperature sensing device located in the conditioned zone that is receiving conditioned and heated air from at least one of said terminuses.