Single exchanger hvac unit and power machines using the same

Abstract

Disclosed embodiments include HVAC systems, and power machines incorporating the same, which utilize an improved exchanger configuration in which the two separate heating and cooling exchangers of conventional systems are replaced with one composite exchanger. The composite heating and cooling exchanger includes nested heating and cooling tubes. The configuration of the tubes can be used to improve conductive efficiency in transferring heat energy to conductive fins, as well as to improve convective efficiency by increasing dwell time of air passing through the exchanger. The disclosed composite exchanger allows for a reduction in the overall exchanger package size package used in an HVAC unit.

What is claimed is: 
     
         1 . A composite exchanger for a heating, ventilating and air conditioning (HVAC) system in a power machine, the composite exchanger comprising:
 a plurality of cooling tubes configured to be coupled to a source of a cooling material and to selectively allow the cooling material to travel in an interior of each of the plurality of cooling tubes;   a plurality of heating tubes configured to be coupled to a source of heating material and to selectively allow the heating material to travel in an interior of each of the plurality of heating tubes; and   a plurality of conductive fins in contact with the plurality of cooling tubes and the plurality of heating tubes to conductively transfer heat energy between the plurality of cooling tubes and the plurality of heating tubes;   wherein the plurality of cooling tubes and the plurality of heating tubes are positioned in a nested arrangement.   
     
     
         2 . The composite exchanger of  claim 1 , wherein the cooling tubes and the heating tubes are nested such that the composite exchanger has alternating rows of cooling tubes and heating tubes. 
     
     
         3 . The composite exchanger of  claim 2 , wherein tubes of a first row of cooling tubes are arranged laterally between a first end and a second end, and wherein at least one tube of a first row of heating tubes is staggered laterally relative to cooling tubes in the first row of cooling tubes. 
     
     
         4 . The composite exchanger of  claim 1 , wherein the plurality of heating tubes and the plurality of cooling tubes are arranged into a first row having a first set of tubes selected from the plurality of heating tubes and the plurality of cooling tubes and a second row having a second set of tubes selected from the plurality of heating tubes and the plurality of cooling tubes, wherein tubes in the first row are arranged laterally between a first end and a second end of the composite exchanger, and wherein at least one of the tubes in the second row is staggered laterally relative to the tubes in the first row. 
     
     
         5 . The composite exchanger of  claim 1 , wherein the plurality of conductive fins are oriented perpendicularly with respect to the plurality of cooling tubes and the plurality of heating tubes. 
     
     
         6 . The composite exchanger of  claim 1 , wherein the plurality of cooling tubes and the plurality of heating tubes are arranged into a plurality of rows each having sets of tubes selected from the plurality of heating tubes and the plurality of cooling tubes, wherein tubes in multiple of the plurality of rows are arranged laterally between a first end and a second end of the composite exchanger, and wherein the tubes in multiple of the plurality of rows are staggered laterally relative to tubes in others of the plurality of rows. 
     
     
         7 . A heating, ventilating and air conditioning (HVAC) system in a power machine, the HVAC system comprising:
 a source of cooling material;   a source of heating material;   a fan; and   a composite exchanger, comprising:
 a plurality of tubes including a first group of tubes coupled to the source of cooling material for selectively receiving cooling material therein and a second group of tubes coupled to the source of heating material for selectively receiving heating material therein; 
 a plurality of conductive fins in contact with the plurality of tubes to conductively transfer heat energy between the first group and the second group of tubes; and 
 wherein the first group of tubes and the second group of tubes are positioned within the composite exchanger in a nested arrangement; and 
   wherein the fan is configured to force air into the composite exchanger across the fins.   
     
     
         8 . The HVAC system of  claim 7 , wherein the plurality of tubes are arranged into rows including a first row of tubes having tubes from one of the first group and the second group of tubes and second and third rows of tubes having tubes from the other of the first group and second group of tubes, wherein the first row is adjacent to the second row and the third row. 
     
     
         9 . The HVAC system of  claim 8 , wherein at least one of the tubes in the second row of tubes is staggered laterally with respect to the first row. 
     
     
         10 . The HVAC system of  claim 9 , wherein at least one of the tubes in the second row of tubes is staggered laterally with respect to the third row. 
     
     
         11 . The HVAC system of  claim 9 , wherein the plurality of conductive fins are oriented perpendicular to the plurality of cooling tubes and the plurality of heating tubes. 
     
     
         12 . A power machine comprising:
 an operator compartment; and   a heating, ventilating and air conditioning (HVAC) system configured to provide conditioned air to the operator compartment, the HVAC system comprising:
 a source of cooling material; 
 a source of heating material; 
 at least one operable input device manipulable to select a heating mode and a cooling mode; 
 a fan; and 
 a composite exchanger having a plurality of tubes arranged in a plurality of rows with each tube coupled to one of the source of cooling material and the source of the heating material and such that one of a plurality of conductive fins is in contact with the plurality of tubes to conductively transfer heat energy between the plurality of tubes coupled to the cooling material and the plurality of tubes coupled to the heating material. 
   
     
     
         13 . The power machine of  claim 12 , wherein the plurality of conductive fins are oriented perpendicularly with respect to the plurality of tubes. 
     
     
         14 . The power machine of  claim 12 , wherein at least one of the rows in the composite exchanger is laterally staggered with respect to another row. 
     
     
         15 . The power machine of  claim 12 , wherein the plurality of rows are arranged into at least one row of tubes that are each coupled to the source cooling material and at least one row of tubes that are each coupled to the source heating material. 
     
     
         16 . The power machine of  claim 15 , wherein the rows are nested such that the composite exchanger has alternating rows of tubes coupled to the cooling material and tubes coupled to the heating material. 
     
     
         17 . The power machine of  claim 12 , wherein multiple of the plurality of conductive fins of the composite exchanger are in contact with the plurality of tubes to conductively transfer heat energy between the plurality of tubes coupled to the cooling material and the plurality of tubes coupled to the heating material.