Laundry Dryer with a Heat Pump System

Abstract

Laundry dryer, with a heat pump system, said heat pump system comprises a refrigerant circuit ( 10 ) for a refrigerant and an drying air stream circuit ( 12 ) for the drying air stream, wherein the refrigerant circuit ( 10 ) includes a compressor ( 14 ) with variable output, a first heat exchanger ( 16 ), variable expansion means ( 18 ) and a second heat exchanger ( 20 ) connected in series and forming a closed loop, the drying air stream circuit ( 12 ) includes the first heat exchanger ( 16 ), the second heat exchanger ( 20 ), a laundry treatment chamber ( 22 ) and at least one air stream fan ( 24 ), the refrigerant circuit ( 10 ) and the air stream circuit ( 12 ) are thermally coupled by the first heat exchanger ( 16 ) and the second heat exchanger ( 20 ), the first heat exchanger ( 16 ) is provided for heating up the air stream and cooling down the refrigerant, and the second heat exchanger ( 20 ) is provided for cooling down the air stream and heating up the refrigerant, wherein a control unit ( 38 ) is provided to adjust the variable expansion means ( 18 ), wherein the control unit ( 38 ) is adapted to adjust the variable expansion means ( 18 ) in response to at least a compressor quantity representative of the operation of the compressor ( 14 ) and/or in response to the drying cycle selected by the user, wherein said quantity is at least one of the following rotational speed of the compressor ( 14 ), supply current/voltage frequency of the compressor motor, absorbed power or current of the compressor ( 14 ).

1 . A laundry dryer with a heat pump system, said heat pump system comprises a refrigerant circuit ( 10 ) for a refrigerant and an drying air stream circuit ( 12 ) for the drying air stream, wherein
 the refrigerant circuit ( 10 ) includes a compressor ( 14 ) with variable output, a first heat exchanger ( 16 ), variable expansion means ( 18 ) and a second heat exchanger ( 20 ) connected in series and forming a closed loop,   the drying air stream circuit ( 12 ) includes the first heat exchanger ( 16 ), the second heat exchanger ( 20 ), a laundry treatment chamber ( 22 ) and at least one air stream fan ( 24 ),   the refrigerant circuit ( 10 ) and the air stream circuit ( 12 ) are thermally coupled by the first heat exchanger ( 16 ) and the second heat exchanger ( 20 ),   the first heat exchanger ( 16 ) is provided for heating up the air stream and cooling down the refrigerant, and   the second heat exchanger ( 20 ) is provided for cooling down the air stream and heating up the refrigerant,   wherein a control unit ( 38 ) is provided to adjust the variable expansion means ( 18 ),   characterized in, that   the control unit ( 38 ) is adapted to adjust the variable expansion means ( 18 ) in response to at least a compressor quantity representative of the operation of the compressor ( 14 ) and/or in response to the drying cycle selected by the user, wherein said quantity is at least one of the following:   rotational speed of the compressor ( 14 ),   supply current/voltage frequency of the compressor motor   absorbed power or current of the compressor ( 14 ).   
     
     
         2 . Laundry dryer according to  claim 1 , wherein the control unit ( 38 ) is adapted to monitor or determine at least one of the compressor quantity and to operate the variable expansion means ( 18 ) accordingly. 
     
     
         3 . Laundry dryer according to  claim 2 , wherein the control unit ( 38 ) is adapted to receive signals representative of at least one of the compressor quantity or the control unit ( 38 ) is adapted to receive signal representative of predetermined parameters, which are the basis for the determination of at least one of the compressor quantity. 
     
     
         4 . Laundry dryer according to any of the preceding claims, wherein the control unit ( 38 ) is adapted to set the variable expansion means ( 18 ) to a reduced lamination work, when the at least one of the compressor quantity is high or starts to increase or increases, the control unit ( 38 ) is adapted to set the variable expansion means ( 18 ) to an increased lamination work, when the at least one of the compressor quantity is low or starts to decrease or decreases. 
     
     
         5 . Laundry dryer according to  claim 1 , comprising at least one drying cycle, in which the compressor ( 14 ) operates at different outputs, and/or comprising different drying cycles, wherein the at least one of the compressor quantity is constant or substantially constant in each drying cycle, but different from drying cycle to drying cycle, wherein the control unit ( 38 ) adjusts the variable expansion means ( 18 ) according to the drying cycle selected by the user. 
     
     
         6 . Laundry dryer according to  claim 5 , wherein the control unit ( 38 ) is adapted to set the variable expansion means ( 18 ) to a reduced lamination work according to an increasing of the at least one of the compressor quantity for the selected drying cycle and to set the variable expansion means ( 18 ) to an increased lamination work according to a decreasing of at least one of the compressor quantity for the selected drying cycle. 
     
     
         7 . Laundry dryer according to  claim 5  or  6 , wherein the control unit ( 38 ) actuates the compressor ( 14 ) to increase the at least one of the compressor quantity according to the selected drying cycle, and automatically actuates the variable expansion means ( 18 ) to a reduced lamination work, further wherein the control unit ( 38 ) actuates the compressor to decrease the at least one of the compressor quantity according to selected drying cycle, and automatically actuates the variable expansion means ( 18 ) to an increased lamination work. 
     
     
         8 . Laundry dryer according to any of the preceding claims, wherein the variable expansion means ( 18 ) comprise at least two capillary tubes ( 28 ,  30 ), wherein at least one of said capillary tubes ( 28 ,  30 ) is switched or switchable by at least one valve ( 26 ;  32 ,  34 ;  36 ). 
     
     
         9 . Laundry dryer according to  claim 8 , wherein the expansion means ( 18 ) comprises at least two parallel series of a capillary tube ( 28 ,  30 ) and a corresponding on-off valve ( 32 ,  34 ) in each case, wherein the capillary tubes ( 28 ,  30 ) have different lengths and/or different cross-sections. 
     
     
         10 . Laundry dryer according to  claim 8 , wherein the expansion means ( 18 ) comprises at least two serial capillary tubes ( 28 ,  30 ), wherein at least one of the capillary tubes ( 28 ,  30 ) is bypassed by an on-off valve ( 36 ). 
     
     
         11 . Laundry dryer according to any of the preceding  claims 8 - 10 , wherein the capillary tubes ( 28 ,  30 ) have different lengths and/or different cross-sections. 
     
     
         12 . Laundry dryer according any of the preceding  claims 8 - 10 , wherein the capillary tubes ( 28 ,  30 ) have the same lengths and cross-sections. 
     
     
         13 . Laundry dryer according to any of the preceding  claims 8 - 12 , wherein the expansion means ( 18 ) comprises two capillary tubes ( 28 ,  30 ) and a three-way valve ( 26 ), wherein the capillary tubes ( 28 ,  30 ) are alternatingly switchable by the three-way valve ( 26 ) and the capillary tubes ( 28 ,  30 ) have different lengths and/or different cross-sections. 
     
     
         14 . Laundry dryer according any of the preceding  claims 1 - 7 , wherein the expansion means ( 18 ) comprises at least one lamination valve including a variable opening degree, so the pressure drop at said expansion means ( 18 ) is adjustable. 
     
     
         15 . The laundry dryer according to any one of the claims, wherein the control unit ( 38 ) is provided for adapting the lamination work at the expansion means ( 18 ) to a warm-up phase and a steady state phase of the process of the heat pump system, wherein the warm-up phase corresponds with a higher lamination work and the steady state phase corresponds with lower lamination work.