Frosting dehumidifier with enhanced defrost

Abstract

A dehumidifier apparatus comprises a housing having an air inlet for receiving incoming air, an air outlet spaced therefrom for allowing the air to exit from the housing, the housing being configured to provide an interior air passageway connecting the air inlet to the air outlet; an air mover mounted within the air passageway for moving the air through the air passageway from the air inlet to the air outlet; a compressor mounted in the housing for compressing a refrigerant; an evaporator located within the air passageway for evaporating the refrigerant during a dehumidifying cycle, and thereby cooling air flowing through the evaporator and causing water in the air to condense on a surface of the evaporator; a condenser for condensing the refrigerant during the dehumidifier cycle, the condenser being located in the air passageway downstream of the evaporator in series with the evaporator; refrigerant flow lines configured to allow for a flow of the refrigerant between the compressor, the condenser, and the evaporator; and a defrosting cycle system for performing a defrosting cycle during a frosting condition of the evaporator, wherein during the defrosting cycle the flow of the refrigerant is reversed, causing the evaporator to condense the refrigerant and the condenser to evaporate the refrigerant. The compressor and the air mover are configured to run continuously during the dehumidifying cycle and the defrosting cycle.

1 . A dehumidifier apparatus, comprising:
 a) a housing having an air inlet for receiving incoming air, an air outlet spaced therefrom for allowing the air to exit from the housing, the housing being configured to provide an interior air passageway connecting the air inlet to the air outlet;   b) an air mover mounted within the air passageway for moving the air through the air passageway from the air inlet to the air outlet;   c) a compressor mounted in the housing for compressing a refrigerant,   d) an evaporator located within the air passageway for evaporating the refrigerant during a dehumidifying cycle, and thereby cooling air flowing through the evaporator and causing water in the air to condense on a surface of the evaporator;   e) a condenser for condensing the refrigerant during the dehumidifying cycle, the condenser being located in the air passageway downstream of the evaporator in series with the evaporator;   f) refrigerant flow lines configured to allow for a flow of the refrigerant between the compressor, the condenser, and the evaporator; and   g) a defrosting cycle system for performing a defrosting cycle during a frosting condition of the evaporator, wherein during the defrosting cycle the flow of the refrigerant is reversed, causing the evaporator to condense the refrigerant and the condenser to evaporate the refrigerant; and   h) wherein the compressor and the air mover are configured to run continuously during the dehumidifying cycle and the defrosting cycle.   
   
   
       2 . The dehumidifier apparatus defined in  claim 1 , wherein the defrosting cycle system comprises:
 a) a reversing valve located in the refrigerant lines for reversing the flow of the refrigerant during the defrosting cycle, thereby causing the   At 53° F., 51% RH: Defrost time was 2 minutes out of every 30 minutes normal run time, for a total cycle time of 32 minutes. Defrost time was 6.7% of run time. Water removal was 28% of its standard rating.   It can be seen from the above test results that a dehumidifier made in accordance with the subject invention has both a lower defrost time and a higher water removal rate than both of the prior art dehumidifiers having conventional defrost systems.   While the above description includes a number of exemplary embodiments, it should be apparent to one skilled in the art that various modifications can be made to the embodiments disclosed herein, without departing from the present invention, the scope of which is defined in the claims. evaporator to condense the refrigerant and the condenser to evaporate the refrigerant;   b) a detector for directly or indirectly detecting the presence of frost on the evaporator; and   c) a controller electrically coupled to the detector and the reversing valve for operating the reversing valve so as to reverse the flow of refrigerant when the temperature reaches pre-determined values.   
   
   
       3 . The dehumidifier apparatus defined in  claim 2 , wherein the detector comprises a sensor for directly or indirectly sensing the temperature of the refrigerant in the evaporator. 
   
   
       4 . The dehumidifier apparatus defined in  claim 1 , wherein the air inlet has bypass holes configured to allow a pre-selected portion of the incoming air to enter a bypass passageway that bypasses the evaporator and joins the air passageway upstream of the condenser. 
   
   
       5 . The dehumidifier apparatus defined in  claim 4 , wherein the pre-selected portion of the incoming air falls in a range of about 5-25% of the incoming air. 
   
   
       6 . The dehumidifier apparatus defined in  claim 1 , wherein the refrigerant flow lines comprise a discharge line allowing refrigerant to flow between the compressor and the reversing valve, a condenser line allowing the refrigerant to flow between the reversing valve and the condenser, a refrigerant metering device allowing the refrigerant to flow between the condenser and the evaporator, an evaporator line allowing the refrigerant to flow between the evaporator and the reversing valve, and a suction line allowing the refrigerant to flow between the reversing valve and the compressor. 
   
   
       7 . The dehumidifier apparatus of  claim 1 , wherein the compressor is located in the air passageway downstream of the condenser. 
   
   
       8 . The dehumidifier apparatus defined in  claim 1 , comprising a drain pan located under the evaporator for collecting the water that has condensed on the surface of the evaporator. 
   
   
       9 . The dehumidifier apparatus defined in  claim 1 , comprising a passive air pre-cooler for cooling the incoming air before the air passes through the evaporator. 
   
   
       10 . The dehumidifier apparatus defined in  claim 9 , wherein the passive air cooler comprises an air-to-air heat exchanger located within the air passageway, the air-to-air heat exchanger having a first pre-cooling air pass upstream of the evaporator and a second pre-heating air pass downstream of the evaporator. 
   
   
       11 . The dehumidifier apparatus defined in  claim 10 , wherein the housing is an upright enclosure having a top end and a bottom end, the air inlet being positioned near the top end of the enclosure and the air outlet being positioned near the bottom end of the enclosure, and wherein the passive air cooler is located directly below the air inlet, the evaporator is located horizontally adjacent to the passive air cooler, and the air passageway is configured to redirect the air exiting the first air pass of the air pre-cooler by about 270 degrees into the evaporator. 
   
   
       12 . The dehumidifier apparatus defined in  claim 11 , wherein the condenser is located below the evaporator, and the air passageway is configured to redirect the air exiting the second pass of the air pre-cooler by about 90 degrees downwardly towards the condenser. 
   
   
       13 . The dehumidifier apparatus defined in  claim 12 , wherein the air mover comprises a blower located below the condenser, the blower being configured to direct the air towards the air outlet. 
   
   
       14 . The dehumidifier apparatus defined in  claim 10 , comprising a drain pan located under the evaporator and the air pre-cooler for collecting the water that has condensed on the evaporator and the air pre-cooler. 
   
   
       15 . The dehumidifier apparatus of  claim 1 , comprising a handle extending backwardly from a back side of the top end of the housing, and a pair of spaced wheels mounted on an axle extending from the back side of the bottom end of the housing, and wherein the evaporator and the condenser are configured within the housing so that the housing may be transported by holding the handle and pivoting the housing backwardly on the wheels without causing gravity drainage of refrigerant from the evaporator to the condenser. 
   
   
       16 . The dehumidifier apparatus of  claim 15 , wherein the evaporator is mounted above the condenser, and the refrigerant lines include a capillary tube having a portion that extends above the top of the evaporator, and wherein the condenser is mounted below the evaporator, with a tilt upward from front to back to prevent drainage of the refrigerant from the condenser to the compressor when the housing is pivoted backwardly on the wheels. 
   
   
       17 . A dehumidifier apparatus, comprising:
 a) a housing having an air inlet for receiving incoming air, an air outlet spaced therefrom for allowing the air to exit from the housing, the housing being configured to provide an interior air passageway connecting the air inlet to the air outlet;   b) a blower mounted within the air passageway for moving the air through the air passageway from the air inlet to the air outlet;   c) a compressor mounted in the housing for compressing a refrigerant,   d) an evaporator located within the air passageway for evaporating the refrigerant during a dehumidifying cycle, and thereby cooling air flowing through the evaporator and causing water in the air to condense on a surface of the evaporator;   e) a condenser for condensing the refrigerant during the dehumidifier cycle, the condenser being located in the air passageway downstream of the evaporator in series with the evaporator;   f) refrigerant flow lines configured to allow for a flow of the refrigerant between the compressor, the condenser, and the evaporator;   g) a reversing valve located in the refrigerant lines for reversing the flow of the refrigerant during a defrosting cycle, thereby causing the evaporator to condense the refrigerant and the condenser to evaporate the refrigerant;   h) a temperature sensor for sensing the temperature of the refrigerant in the evaporator; and   i) a controller operatively coupled to the temperature sensor and the reversing valve for operating the reversing valve so as to reverse the flow of refrigerant when the temperature reaches pre-determined values.   
   
   
       18 . The dehumidifier apparatus defined in  claim 17 , wherein the controller is operatively coupled to the blower and the compressor and is configured to enable the compressor and the blower to run continuously during both the dehumidifying cycle and the defrosting cycle. 
   
   
       19 . The dehumidifier apparatus defined in  claim 17 , wherein the air inlet has bypass holes configured to allow a pre-selected portion of the incoming air to enter a bypass passageway that bypasses the evaporator and joins the air passageway upstream of the condenser. 
   
   
       20 . The dehumidifier apparatus defined in  claim 17 , comprising a passive air pre-cooler for cooling the incoming air before the air passes through the evaporator, wherein the passive air cooler comprises an air-to-air heat exchanger located within the air passageway, the air-to-air heat exchanger having a first pre-cooling air pass upstream of the evaporator and a second pre-heating air pass downstream of the evaporator.