Integrated hydronic heating and refrigerant cooling heat exchanger

Abstract

The disclosed technology includes devices and systems for air handling units used in heating ventilation and air conditioning (HVAC) systems. The disclosed technology can include a unitary heat exchanger structure configured to be positioned in an airflow path of an HVAC system and comprising a refrigerant heat exchanger coil and a hydronic heat exchanger coil. The refrigerant heat exchanger can include a refrigerant flow path configured to (i) receive a refrigerant circulated through the refrigerant heat exchanger coil and (ii) facilitate heat exchange between the refrigerant and air directed across the refrigerant heat exchanger coil. The hydronic heat exchanger coil can include a water flow path configured to (a) receive water circulated through the hydronic heat exchanger coil and (b) facilitate heat exchange between the water and air directed across the hydronic heat exchanger coil.

What is claimed is: 
     
         1 . A unitary heat exchanger structure for a heating, ventilation, and air conditioning (HVAC) system, the unitary heat exchanger structure comprising:
 a refrigerant heat exchanger coil and a hydronic heat exchanger coil, the unitary heat exchanger structure configured to be positioned in an air flow path of the HVAC system;   the refrigerant heat exchanger coil comprising:
 a refrigerant flow path configured to (i) receive a refrigerant circulated through the refrigerant heat exchanger coil and (ii) facilitate heat exchange between the refrigerant and air directed across the refrigerant heat exchanger coil; and the hydronic heat exchanger coil comprising: 
 a water flow path configured to (a) receive water circulated through the hydronic heat exchanger coil and (b) facilitate heat exchange between the water and air directed across the hydronic heat exchanger coil. 
   
     
     
         2 . The unitary heat exchanger structure of  claim 1 , wherein the refrigerant heat exchanger coil comprises a first tube having a first cross-sectional area and the hydronic heat exchanger coil comprises a second tube having a second cross-sectional area, the second cross-sectional area being greater than the first cross-sectional area. 
     
     
         3 . The unitary heat exchanger structure of  claim 1 , wherein the refrigerant heat exchanger coil is configured to be in a downstream position relative the hydronic heat exchanger coil when the unitary heat exchanger structure is installed in the HVAC system. 
     
     
         4 . The unitary heat exchanger structure of  claim 1 , wherein the hydronic heat exchanger coil is configured to be in a downstream position relative the refrigerant heat exchanger coil when the unitary heat exchanger structure is installed in the HVAC system. 
     
     
         5 . The unitary heat exchanger structure of  claim 4 , wherein the hydronic heat exchanger coil is configured to reheat the air passed through the refrigerant heat exchanger coil. 
     
     
         6 . The unitary heat exchanger structure of  claim 1 , wherein the unitary heat exchanger structure comprises a microchannel heat exchanger. 
     
     
         7 . The unitary heat exchanger structure of  claim 6 , wherein the refrigerant heat exchanger coil and the hydronic heat exchanger coil are interlaced. 
     
     
         8 . The unitary heat exchanger structure of  claim 6 , wherein the refrigerant heat exchanger coil comprises a first flat tube having a first cross-sectional area and the hydronic heat exchanger coil comprises a second flat tube having a second cross-sectional area, the second cross-sectional area being greater than the first cross-sectional area. 
     
     
         9 . The unitary heat exchanger structure of  claim 8 , wherein the hydronic heat exchanger coil comprises a turbulator. 
     
     
         10 . The unitary heat exchanger structure of  claim 1 , wherein the unitary heat exchanger structure further comprises a plurality of fins connecting the refrigerant heat exchanger coil and the hydronic heat exchanger coil, the plurality of fins configured to facilitate heat exchange between the refrigerant and air and the water and air. 
     
     
         11 . An air handling unit for a heating, ventilation, and air conditioning (HVAC) system, the air handling unit comprising:
 a housing;   an air inlet;   an air outlet;   an air moving device configured to move air from the air inlet, through the housing, and out the air outlet; and   a unitary heat exchanger structure disposed at last partially within the housing, the unitary heat exchanger structure comprising:
 a first heat exchanger coil configured to receive refrigerant and facilitate heat exchange between the refrigerant and air directed across the first heat exchanger coil by the air moving device; and 
 a second heat exchanger coil configured to receive water and facilitate heat exchange between the water and air directed across the second heat exchanger coil by the air moving device. 
   
     
     
         12 . The air handling unit of  claim 11 , wherein the first heat exchanger coil comprises a first tube having a first cross-sectional area and the second heat exchanger coil comprises a second tube having a second cross-sectional area, the second cross-sectional area being greater than the first cross-sectional area. 
     
     
         13 . The air handling unit of  claim 11 , wherein the first heat exchanger coil is positioned in an airflow path downstream of the second heat exchanger. 
     
     
         14 . The air handling unit of  claim 11 , wherein the second heat exchanger coil is positioned in an airflow path downstream of the first heat exchanger. 
     
     
         15 . The air handling unit of  claim 14 , wherein the second heat exchanger is configured to reheat the air passed through the first heat exchanger coil. 
     
     
         16 . The air handling unit of  claim 11 , wherein the unitary heat exchanger structure comprises a microchannel heat exchanger. 
     
     
         17 . The air handling unit of  claim 16 , wherein the first heat exchanger coil comprises a first flat tube having a first cross-sectional area and the second heat exchanger coil comprises a second flat tube having a second cross-sectional area, the second cross-sectional area being greater than the first cross-sectional area. 
     
     
         18 . The air handling unit of  claim 16 , wherein the second heat exchanger coil comprises a turbulator. 
     
     
         19 . The air handling unit of  claim 16 , wherein the first heat exchanger coil and the second heat exchanger coil are interlaced. 
     
     
         20 . An HVAC system comprising the air handling unit of  claim 11 , the HVAC system further comprising a tankless water heater configured to supply heated water to the second heat exchanger coil.