System and method for controlling air temperature in an appliance

Abstract

An apparatus and method for controlling air temperature in an appliance. The apparatus includes an air cooling unit disposed in an airflow path and an air heating unit disposed in the airflow path and fluidically coupled to the air cooling unit by a refrigerant. The apparatus also includes a de-heater fluidically coupled to the air cooling unit and the air heating unit by the refrigerant to controllably dissipate heat from the refrigerant.

1 . An apparatus comprising: 
 an air cooling unit disposed in an airflow path;    an air heating unit disposed in the airflow path and fluidically coupled to the air cooling unit by a refrigerant; and    a de-heater fluidically coupled to the air cooling unit and the air heating unit by the refrigerant to controllably dissipate heat from the refrigerant.    
   
   
       2 . The apparatus of  claim 1 , wherein the heat is controllably dissipated from the refrigerant such that an airflow following the airflow path is prevented from exceeding a determined temperature.  
   
   
       3 . The apparatus of  claim 1 , wherein the apparatus further comprises: 
 a blower to generate an airflow along the airflow path; and    a drum to contain at least one article for drying, the drum positioned to receive the airflow.    
   
   
       4 . The apparatus of  claim 3  further comprising a controller coupled to the air cooling unit, the air heating unit and the de-heater to control an exchange of heat between the airflow and the refrigerant.  
   
   
       5 . The apparatus of  claim 4 , wherein the apparatus further comprises a first air sensor positioned at an inlet of the drum to sense air temperature at the inlet of the drum and configured to send a signal indicative of the air temperature at the inlet of the drum to the controller.  
   
   
       6 . The apparatus of  claim 4  further comprising a bypass valve to cause at least a portion of the airflow to controllably bypass the air cooling unit.  
   
   
       7 . The apparatus of  claim 4 , wherein the apparatus further comprises a second air sensor positioned at an outlet of the air cooling unit to sense air temperature at the outlet of the air cooling unit and configured to send a signal indicative of the air temperature at the outlet of the air cooling unit to the controller.  
   
   
       8 . The apparatus of  claim 4 , further comprising: 
 a compressor fluidically coupled to the air cooling unit, the air heating unit, and the de-heater to compress the refrigerant; and    an expansion chamber fluidically coupled to the air heating unit to receive the refrigerant from the air heating unit to provide expansion and cooling of the refrigerant.    
   
   
       9 . The apparatus of  claim 8 , wherein the air heating unit comprises a condenser fluidically coupled to the de-heater to receive the refrigerant exiting from the de-heater, the condenser further in thermal connection with the airflow to transfer heat from the refrigerant to the airflow; and 
 wherein the air cooling unit is an evaporator fluidically coupled between the compressor and the expansion chamber to receive the refrigerant exiting from the expansion chamber, the evaporator further in thermal connection with the airflow to transfer the heat from the airflow to the refrigerant, wherein the refrigerant exiting from the evaporator is circulated back to the compressor.    
   
   
       10 . The apparatus of  claim 9  further comprising a fan coupled to the de-heater to provide a second airflow to cool refrigerant passing through the de-heater.  
   
   
       11 . The apparatus of  claim 10 , wherein operation of the fan is controlled by the controller such that the compressor can operate continuously during heat dissipation from the refrigerant.  
   
   
       12 . The apparatus of  claim 11 , further comprising a thermocouple positioned at an outlet of the de-heater to sense temperature of the refrigerant at the outlet of the de-heater and configured to send a signal indicative of the temperature of the refrigerant at the outlet to the controller.  
   
   
       13 . A method for controlling air temperature in an appliance, the method comprising: 
 disposing an air cooling unit in an airflow path designed to carry an airflow;    disposing an air heating unit in the airflow path and fluidically coupling the air heating unit to the air cooling unit by a refrigerant; and    disposing a de-heater and fluidically coupling the de-heater to the air cooling unit and the air heating unit by the refrigerant to controllably dissipate heat from the refrigerant.    
   
   
       14 . The method of  claim 13 , wherein the heat is controllably dissipated based at least in part upon a temperature of the refrigerant.  
   
   
       15 . The method of  claim 13  further comprising: 
 in the air heating unit, transferring heat from the refrigerant to the airflow to heat the airflow; and    in the air cooling unit, transferring heat from the airflow to the refrigerant to cool the airflow, wherein the refrigerant exiting from the air cooling unit is compressed to further heat the refrigerant.    
   
   
       16 . In an appliance, a method comprising: 
 defining an airflow path to carry an airflow for drying articles within the appliance;    defining a refrigerant flow path to circulate a refrigerant in a closed loop such that the refrigerant acts at least in part to both heat and cool the airflow; and    controlling temperature of the refrigerant such that the airflow does not exceed a determined temperature.    
   
   
       17 . The method of  claim 16  further comprising: 
 generating the airflow;    removing heat from the airflow to create a cooled airflow by exposing the airflow to the refrigerant having a first state;    adding a controlled amount of heat to the cooled airflow to create a heated airflow by exposing the cooled airflow to the refrigerant in a second state; and    providing the heated airflow to the articles in the appliance.    
   
   
       18 . The method of  claim 17  further comprising: 
 cooling the refrigerant to a first temperature;    flowing the refrigerant through an evaporator positioned in the airflow path to cool the airflow;    heating the refrigerant to a temperature that does not exceed the determined temperature; and    flowing the heated refrigerant through a condenser to heat the airflow.    
   
   
       19 . The method of  claim 18 , wherein heating the refrigerant to a temperature that does not to exceed the determined temperature comprises: 
 compressing the refrigerant;    flowing the heated refrigerant through a second condenser;    determining whether the temperature of the heated refrigerant is equal to or exceeds the determined temperature; and    controllably generating a secondary airflow and directing the secondary airflow toward the second condenser to remove heat from the refrigerant when the temperature of the heated refrigerant is equal to or exceeds the determined temperature.    
   
   
       20 . The method of  claim 19 , wherein cooling the refrigerant comprises allowing the compressed refrigerant to expand in volume.  
   
   
       21 . The method of  claim 19 , wherein the second condenser operates to remove super heat from the refrigerant.