Hvac roof curb retrofit

Abstract

A ventilation adapter unit or roof curb retrofit is provided for reducing energy costs in operating a building ventilation system. The unit is disposed between a traditional HVAC unit and a surface of the building, and has a plurality of internal passageways including a return air passageway, a discharge air passageway, and a supplemental discharge air passageway. Air entering the discharge air passageway from the HVAC unit is selectively routed into the supplemental discharge air passageway, where it is cooled by a cooling panel according to the position of a damper in the discharge air passageway. The cooling panel receives chilled fluid from a chiller, such as an ice storage system that operates a refrigeration unit during off-peak hours. Regardless of whether the air is routed through or around the damper, the air is then discharged from the retrofit unit and into the building.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A ventilation adapter unit for a building ventilation system, said adapter unit comprising:
 a main housing defining an inner chamber, said main housing including first and second end portions, said first end portion configured to engage an exterior building surface associated with the building ventilation system, and said second end portion configured to engage a powered ventilation unit of the building ventilation system;   a plurality of interior walls dividing said inner chamber into a plurality of passageways including (i) a return air passageway open at both said first and second end portions of said main housing, (ii) a discharge air passageway open at both said first and second end portions of said main housing, and (iii) a supplemental discharge air passageway having an inlet portion in fluid communication with said discharge air passageway near said open second end portion of said main housing and an outlet portion in fluid communication with said discharge air passageway near said open first end portion of said main housing;   a heat exchanger disposed in said supplemental discharge air passageway; and   a damper disposed in said discharge air passageway between said first and second end portions of said main housing and positionable between an open position and a closed position;   wherein when said damper is in the open position, a flow of discharge air is permitted to pass from the powered ventilation unit through said second end portion of said main housing and substantially directly out through said first end portion of said main housing, and when said damper is in the closed position, the flow of discharge air is directed into said supplemental air passageway, through said heat exchanger, and out through said first end portion of said main housing.   
     
     
         2 . The ventilation adapter unit of  claim 1 , wherein said damper is oriented along a diagonal with a first end portion located proximate said first end portion of said main housing and a second end portion located proximate said second end portion of said main housing. 
     
     
         3 . The ventilation adapter unit of  claim 2 , wherein said plurality of interior walls comprises a first interior wall positioned between said damper and said inlet portion of said supplemental discharge air passageway, and wherein said first interior wall defines a generally triangular opening at said inlet portion of said supplemental discharge air passageway. 
     
     
         4 . The ventilation adapter unit of  claim 1 , wherein said heat exchanger comprises a cooling panel in fluid communication with a chiller. 
     
     
         5 . The ventilation adapter unit of  claim 4 , further in combination with the chiller, wherein said chiller comprises an ice storage unit. 
     
     
         6 . The ventilation adapter unit of  claim 4 , further comprising a controller, wherein said controller is operable to selectively actuate said damper to the closed position and to activate the chiller to thereby circulate chilled fluid through said cooling panel. 
     
     
         7 . The ventilation adapter unit of  claim 6 , wherein said controller is operable in response to at least one chosen from (i) a thermostat located in a room of the building, (ii) a real time clock, and (iii) a chiller status signal. 
     
     
         8 . The ventilation adapter unit of  claim 7 , wherein said controller is further operable to selectively energize a blower and an air conditioner of the powered ventilation unit. 
     
     
         9 . The ventilation adapter unit of  claim 8 , wherein said controller is operable to simultaneously (i) energize the blower of the powered rooftop ventilation unit, (ii) de-energize the air conditioner of the powered rooftop ventilation unit, (iii) actuate said damper to the closed position, and (iv) activate said chiller. 
     
     
         10 . A roof curb retrofit unit comprising:
 a main housing comprising perimeter walls that cooperate to define an inner chamber, a lower portion for engaging a roof curb, and an upper portion for engaging a powered rooftop ventilation unit;   a plurality of interior walls dividing said inner chamber into a plurality of passageways including (i) a return air passageway open at both said upper and lower portions of said main housing, (ii) a discharge air passageway open at both said upper and lower portions of said main housing, and (iii) a supplemental discharge air passageway having an inlet portion in fluid communication with said discharge air passageway near said open upper portion of said main housing and an outlet portion in fluid communication with said discharge air passageway near said open lower portion of said main housing;   a cooling panel disposed in said supplemental discharge air passageway between said inlet and outlet portions thereof, said cooling panel configured to permit a flow of air therethrough and to remove heat from the air; and   a damper disposed in said discharge air passageway between said upper and lower portions of said main housing, wherein said damper is configurable between an open position and a closed position;   wherein when said damper is in the open position, a flow of discharge air is permitted to pass from the rooftop ventilation unit through said upper portion of said main housing and substantially directly out through said lower portion of said main housing, and when said damper is in the closed position, the flow of discharge air is directed into said supplemental air passageway, through said cooling panel, and out through said lower portion of said main housing.   
     
     
         11 . The roof curb retrofit unit of  claim 10 , wherein said main housing comprises a bottom panel attached to said perimeter walls, said bottom panel defining openings only at said return air passageway and at said discharge air passageway. 
     
     
         12 . The roof curb retrofit unit of  claim 11 , wherein said damper is oriented along a diagonal relative to a horizontal plane, and comprises an upper end portion proximate said upper portion of said main housing and a lower end portion proximate said lower portion of said main housing. 
     
     
         13 . The roof curb retrofit unit of  claim 10 , wherein said plurality of interior walls comprise a first interior wall positioned between said damper and said inlet portion of said supplemental discharge air passageway, and wherein said first interior wall defines a generally triangular opening at said inlet portion of said supplemental discharge air passageway. 
     
     
         14 . The roof curb retrofit unit of  claim 10 , wherein an entirety of the flow of discharge air entering said discharge air passageway passes through said damper or said cooling panel. 
     
     
         15 . The roof curb retrofit unit of  claim 10 , wherein said cooling panel is in fluid communication with a chiller. 
     
     
         16 . The roof curb retrofit unit of  claim 15 , further comprising a controller, wherein said controller is operable to selectively actuate said damper to the closed position and to activate the chiller to thereby circulate chilled fluid through said cooling panel. 
     
     
         17 . The roof curb retrofit unit of  claim 16 , wherein said controller is operable in response to at least one chosen from (i) a thermostat located in a room of a building on which said roof curb retrofit unit is mounted, (ii) a real time clock, (iii) a chiller status signal. 
     
     
         18 . The roof curb retrofit unit of  claim 17 , wherein said controller is further operable to selectively energize a blower and an air conditioner of the powered rooftop ventilation unit. 
     
     
         19 . The roof curb retrofit unit of  claim 18 , wherein said controller is operable to simultaneously (i) energize the blower of the powered rooftop ventilation unit, (ii) de-energize the air conditioner of the powered rooftop ventilation unit, (iii) actuate said damper to the closed position, and (iv) activate said chiller. 
     
     
         20 . A method of operating a roof curb retrofit unit, said method comprising:
 directing return air from a building interior to a return air passageway of the roof curb retrofit unit;   directing the return air from the return air passageway to a powered rooftop ventilation unit coupled to the roof curb retrofit unit;   passing the return air through a blower of the powered rooftop ventilation unit to convert the return air to discharge air;   directing the discharge air from the powered rooftop ventilation unit to a discharge air passageway of the roof curb retrofit unit;   closing a damper that is disposed in the discharge air passageway to thereby direct the discharge air (i) into an inlet portion of a supplemental discharge air passageway of the roof curb retrofit unit that is in fluid communication with the discharge air passageway, (ii) through a cooling panel disposed in the supplemental discharge air passageway, and (iii) out of the roof curb retrofit unit through an outlet portion of the discharge air passageway;   opening the damper to thereby direct the discharge air through the damper and directly to the outlet portion of the discharge air passageway so that the discharge air substantially bypasses the supplemental discharge air passageway; and   circulating a cooling fluid through the cooling panel when the damper is closed.