Self-contained pre-manufactured air unit for installation on a roof of a building

Abstract

A self-contained pre-manufactured air unit for installation on a roof of a building and method of operation thereof has a relief passage for connection to a building to receive relief air from the building when air pressure within the building exceeds a pressure of ambient air. The relief passage is independent of an air circulation system and is located to exhaust relief air over the condenser coil to ambient air through at least one condenser fan, thereby decreasing a temperature of a refrigerant in the condenser coil.

We claim: 
     
         1 . A self-contained pre-manufactured air unit for installation on a roof of a building, for circulating air through the building, the unit comprising a housing having a blower therein, a condenser coil containing refrigerant and a compressor, a first passage to supply air to the building, a second passage to receive return air from the building, the blower connected to circulate air into and out of the building through the first passage and the second passage respectively, the blower and the first passage and second passage comprising an air circulation system that is located in a second portion of the housing, a relief passage for connection to the building to receive relief air from the building when air pressure within the building exceeds a pressure of ambient air, the relief passage being independent of the air circulation system and located to exhaust relief air over the condenser coil to ambient air through at least one condenser fan, thereby decreasing a temperature of the refrigerant, the relief passage and at least one condenser coil located in a first portion of the housing. 
     
     
         2 . The air unit as claimed in  claim 1  wherein the first portion of the housing is ambient air accessible to an area of the relief passage to allow ambient air to mix with relief air and to flow over the condenser coil. 
     
     
         3 . The air unit as claimed in  claim 2  wherein the first portion of the housing is open to ambient air near the relief passage. 
     
     
         4 . The air unit as claimed in  claim 1  wherein the condenser coil is one selected from the group of a heating coil, a cooling coil and a heating/cooling coil. 
     
     
         5 . The air unit as claimed in  claim 1  wherein a compressor for the coil is located in the second portion of the housing. 
     
     
         6 . A method of operating a self-contained pre-manufactured air unit for installation on a roof of a building, the unit comprising a housing having a blower therein a condenser coil containing refrigerant and a compressor, a first passage to supply air to the building, a second passage to receive return air from the building, the blower connected to circulate air into and out of the building through the first passage and the second passage respectively, the blower, the first passage and second passage comprising an air circulation system, a method comprising locating a relief passage for connection to the building to receive relief air from the building when air pressure was in the building exceeds a pressure of ambient air, locating the relief passage to be independent of the air circulation system and to exhaust relief air over the condenser coil to ambient air through at least one condenser fan to decrease a temperature of the refrigerant locating the coil in a first portion of the housing and locating the first passage, the second passage and the blower in a second portion of the housing.