Evaporator with integrated heating element

Abstract

An evaporator coil includes a conduit having an interior passageway that provides a pathway for a flow of refrigerant. An outer wall of the conduit forms a channel having a longitudinal opening. The channel extends lengthwise adjacent to the interior passageway. The channel contains an electrical heating element that is in thermal contact with the conduit. The electrical heating element periodically provides heat to defrost the evaporator coil during an evaporator defrost cycle. The electrical heating element may be coupled directly to the channel or be housed within a second conduit that is at least partially contained within the channel.

1 . An evaporator coil comprising:
 a conduit having an interior passageway that provides a pathway for a flow of refrigerant and an outer wall that forms a channel having a longitudinal opening, the channel extending lengthwise adjacent to the interior passageway; and   an electrical heating element in the channel and in thermal contact with the conduit, the electrical heating element periodically providing heat to defrost the evaporator coil during an evaporator defrost cycle.   
     
     
         2 . The evaporator coil of  claim 1 , wherein the electrical heating element is coupled to the channel. 
     
     
         3 . The evaporator coil of  claim 2 , wherein the electrical heating element is coupled to the outer wall by a thermally conductive adhesive or by a weld between the electrical heating element and the channel. 
     
     
         4 . The evaporator coil of  claim 1 , further comprising a second conduit at least partially contained within the channel, wherein the electrical heating element is contained within the second conduit. 
     
     
         5 . The evaporator coil of  claim 4 , wherein the second conduit has an outer wall that is contoured to fit in the channel. 
     
     
         6 . The system of  claim 5 , further comprising a medium in the second conduit that facilitates heat transfer between the electrical heating element and the second conduit. 
     
     
         7 . The evaporator coil of  claim 4 , wherein the first conduit and the second conduit are formed from different materials. 
     
     
         8 . The evaporator coil of  claim 1 , wherein the electrical heating element is a resistive heating element. 
     
     
         9 . The evaporator coil of  claim 1 , wherein the first conduit and the second conduit are extruded. 
     
     
         10 . The evaporator coil of  claim 1 , wherein the conduit has longitudinal and curved portions and the channel extends substantially the full length of the conduit. 
     
     
         11 . The evaporator coil of  claim 1  in an evaporator that is part of a refrigeration system having an evaporator defrost cycle, wherein the evaporator coil has an inlet portion configured to interface with a first conduit of a refrigeration system, and an outlet portion configured to interface with a second conduit of a refrigeration system. 
     
     
         12 . The system of  claim 11 , wherein at least one of the first conduit of the refrigeration system and the second conduit of the refrigeration system has a tapered channel that corresponds to one of the channels in the evaporator coil. 
     
     
         13 . The system of  claim 12 , further comprising a controller that controls the refrigeration system to alternate between operation of the refrigeration system and an evaporator defrost cycle. 
     
     
         14 . An evaporator coil comprising:
 a first conduit having an interior passageway that provides a pathway for a flow of refrigerant and an outer wall that forms a channel having a longitudinal opening, the channel extending lengthwise adjacent to the interior passageway;   a second conduit having an interior passageway that provides a pathway for an electrical heating element, the second conduit at least partially contained within the channel of the first conduit; and   an electrical heating element in the second channel, the electrical heating element periodically providing heat to defrost the evaporator coil during an evaporator defrost cycle.