Air Conditioner Units with Improved Make-Up Air System

Abstract

An air conditioner unit and methods of operating the same is provided. The air conditioner unit may include a refrigeration loop having a variable speed compressor, an electronic expansion valve, an indoor heat exchanger, and an outdoor heat exchanger. An indoor fan and an outdoor fan may be configured to urge air through the indoor and outdoor heat exchangers, respectively. A bulkhead may be disposed between the indoor heat exchanger and the outdoor heat exchanger to define an indoor portion and an outdoor portion of the unit. A vent aperture may be defined in the bulkhead, and the indoor and outdoor fans may be configured to urge make-up air from the outdoor portion through the vent aperture to the indoor portion. In addition, an auxiliary fan may be disposed within the vent aperture to provide additional “boost” make-up air, and a heating bank may be used to heat make-up air if desired.

What is claimed is: 
     
         1 . An air conditioner unit for conditioning an indoor space, comprising:
 an outdoor heat exchanger assembly disposed in an outdoor portion and comprising an outdoor heat exchanger and an outdoor fan;   an indoor heat exchanger assembly disposed in an indoor portion and comprising an indoor heat exchanger and an indoor fan;   a compressor configured for circulating a refrigerant between the outdoor heat exchanger and the indoor heat exchanger;   a bulkhead disposed between the outdoor heat exchanger and the indoor heat exchanger along a transverse direction, the bulkhead defining the indoor portion and the outdoor portion;   a vent aperture defined in the bulkhead;   a damper positioned proximate the vent aperture and configured to move between an open position where the outdoor portion is in fluid communication with the indoor portion and a closed position where the damper blocks the vent aperture to prevent fluid communication between the outdoor portion and the indoor portion; and   a controller configured to open the damper and operate the indoor fan at less than full speed when a negative pressure condition is sensed to force make-up air out of the air conditioner unit.   
     
     
         2 . The air conditioner unit of  claim 1 , further comprising an auxiliary fan disposed at the vent aperture and configured to sense when there is a negative pressure condition in the indoor portion. 
     
     
         3 . The air conditioner unit of  claim 2 , wherein the controller is further configured to operate the auxiliary fan to force additional make-up air out from outdoors into the indoor space if the negative pressure condition is sensed and a boost mode is activated. 
     
     
         4 . The air conditioner unit of  claim 3 , wherein a make-up air flowrate when the boost mode is deactivated is about 25 cubic feet per minute and the make-up air flowrate when the boost mode is activated is about 50 cubic feet per minute. 
     
     
         5 . The air conditioner unit of  claim 1 , wherein the compressor is a variable speed compressor, the air conditioner unit further comprising:
 an electronic expansion valve configured to control the expansion of the refrigerant before it reaches the indoor heat exchanger; and   a humidity sensor disposed within the indoor portion,   wherein the controller is configured to operate the variable speed compressor, the outdoor fan, and the indoor fan at less than full speed and to operate the electronic expansion valve responsive to a speed of the variable speed compressor when an indoor humidity level sensed by the humidity sensor is above a predetermined humidity threshold.   
     
     
         6 . The air conditioner unit of  claim 5 , wherein the predetermined humidity threshold is greater than or equal to 55%. 
     
     
         7 . The air conditioner unit of  claim 1 , further comprising:
 a temperature sensor disposed within the indoor portion proximate the vent aperture to sense a temperature of make-up air; and   a heater bank positioned within the indoor portion,   wherein the controller is configured to activate the heater bank if the sensed temperature of the make-up air from the outdoors is below a predetermined temperature threshold.   
     
     
         8 . The air conditioner unit of  claim 7 , wherein the predetermined temperature threshold is a set point temperature of the air conditioner unit. 
     
     
         9 . The air conditioner unit of  claim 1 , wherein the damper is driven by an electric motor. 
     
     
         10 . The air conditioner unit of  claim 1 , wherein the controller is configured to close the damper when the negative pressure condition is not sensed. 
     
     
         11 . A method for providing make-up air from the outdoors through an air conditioner unit into an indoor space, the air conditioner unit having an indoor portion with an indoor heat exchanger and an indoor fan, an outdoor portion with an outdoor heat exchanger, a bulkhead positioned along a transverse direction between the indoor portion and the outdoor portion, the bulkhead defining an aperture between the indoor portion and outdoor portion the method comprising:
 determining whether a negative pressure condition exists within the indoor portion of the air conditioner unit and, if a negative pressure condition exists, then
 opening the damper and operating the indoor fan at less than full speed to force make-up air through the air conditioner unit and into the indoor space. 
   
     
     
         12 . The method of  claim 11 , wherein the air conditioner unit further comprises an auxiliary fan positioned adjacent to the vent aperture, and wherein the negative pressure condition is determined by sensing the rotation of the auxiliary fan. 
     
     
         13 . The method of  claim 12 , further comprising activating a boost mode so as to operate the auxiliary fan and force additional make-up air out through the air conditioner unit and into the indoor space if the negative pressure condition is sensed. 
     
     
         14 . The method of  claim 13 , wherein a make-up air flowrate when the boost mode is deactivated is about 25 cubic feet per minute and the make-up air flowrate when the boost mode is activated is about 50 cubic feet per minute. 
     
     
         15 . The method of  claim 11 , further comprising:
 providing a humidity sensor disposed within the indoor portion that is configured to measure the indoor humidity level and, if an indoor humidity level is above a predetermined indoor humidity level threshold, then
 operating a variable speed compressor, an outdoor fan, and the indoor fan at less than full speed, and 
 operating an electronic expansion valve based on a temperature differential across the indoor heat exchanger. 
   
     
     
         16 . The method of  claim 15 , wherein the predetermined humidity threshold is greater than or equal to 55%. 
     
     
         17 . The method of  claim 11 , further comprising:
 sensing a temperature of the make-up air using a temperature sensor disposed within the indoor portion proximate the vent aperture; and   activating a heater bank if the sensed temperature of the make-up air is below a predetermined temperature threshold.   
     
     
         18 . The method of  claim 11 , further comprising closing the damper when a negative pressure condition is not determined. 
     
     
         19 . An air conditioner unit for conditioning an indoor space, comprising:
 an outdoor heat exchanger assembly disposed in an outdoor portion and comprising an outdoor heat exchanger and a variable speed outdoor fan;   an indoor heat exchanger assembly disposed in an indoor portion and comprising an indoor heat exchanger and a variable speed indoor fan;   a variable speed compressor configured for circulating a refrigerant between the outdoor heat exchanger and the indoor heat exchanger;   an electronic expansion valve configured to control the expansion of the refrigerant before it reaches the indoor heat exchanger;   a bulkhead disposed between the outdoor heat exchanger and the indoor heat exchanger along a transverse direction, the bulkhead defining the indoor portion and the outdoor portion;   a vent aperture defined in the bulkhead;   a damper positioned proximate the vent aperture and configured to move between an open position where the outdoor portion is in fluid communication with the indoor portion and a closed position where the damper blocks the vent aperture to prevent fluid communication between the outdoor portion and the indoor portion; and   a controller configured to open the damper and operate the variable speed compressor, the electronic expansion valve, the indoor fan, and the outdoor fan to induce and condition make-up air that passes through the vent aperture.   
     
     
         20 . The air conditioner unit of  claim 19 , further comprising an auxiliary fan disposed at the vent aperture and configured to force additional make-up air out from outdoors into the indoor space if a boost mode is activated.