Household Appliance For Drying Objects

Abstract

In order to obtain satisfactory energy efficiency and environmental compatibility, a household tumble dryer ( 1 ) is proposed that includes a drying chamber ( 2 ) adapted to accommodate therein objects ( 3 ) to be dried. A first circuit is provided for impinging the drying chamber ( 2 ) with a drying medium ( 4 ). The dryer further includes a heat pump ( 5 ) with a second circuit for circulating a heat exchange medium. The first and second circuit are coupled in a heat exchanging manner. The heat exchange medium is of a hydro-fluoro-olefine type.

1 . A household appliance for drying objects, in particular laundry, comprising a drying chamber adapted to accommodate therein the objects, and a first circuit for impinging the drying chamber with a drying medium in a circulating manner, and further comprising a heat pump with a second circuit for circulating a heat exchange medium, wherein the first and second circuits are coupled in a heat exchanging manner, and wherein the heat exchange medium is of a hydro-fluoro-olefine type. 
     
     
         2 . A household appliance according to  claim 1 , the hydro-fluoro-olefine comprising a tetra-fluoro-propene, in particular 1,1,1,2-tetra-fluoro-propene and/or 1,1,1,3-tetra-fluoro-propene. 
     
     
         3 . A household appliance according to  claim 1 , wherein a critical temperature of the heat exchange medium lies in a range from 90° C. to 115° C. 
     
     
         4 . A household appliance according to  claim 1 , wherein a critical pressure of the heat exchange medium lies in a range from 25 to 40 bar. 
     
     
         5 . A household appliance according to  claim 1 , wherein the nominal heat of vaporization at the boiling point of the heat exchange medium lies in a range from 160 to 215 kJ/kg. 
     
     
         6 . A household appliance according to  claim 1 , wherein the global warming potential index of the heat exchange medium lies in a range from 1 to 15. 
     
     
         7 . A household appliance according to  claim 1 , wherein the heat exchange medium has at least one of a lower flammability level of about 6.2 Vol % and an upper flammability level of about 12.3 Vol %. 
     
     
         8 . A household appliance according to  claim 1 , wherein the heat exchange medium has at least one of a minimum ignition energy of more than 3000 mJ and a burning velocity of about 1.5 cm/s. 
     
     
         9 . A household appliance according to  claim 1 , wherein the heat pump has a nominal cooling power between about 500 W and 3,500 W. 
     
     
         10 . A household appliance according to  claim 1 , wherein the heat pump comprises an evaporator heat exchanger for transferring heat from the drying medium to the heat exchange medium, and wherein the appliance is adapted such that in operation a nominal evaporator heat exchanger inlet temperature of the drying medium is at least about 30° C. 
     
     
         11 . A household appliance according to  claim 1 , wherein the heat pump comprises a liquefier heat exchanger for transferring heat from the heat exchange medium to the drying medium, and wherein the appliance is adapted such that in operation a nominal liquefier heat exchanger outlet temperature of the drying medium is 100° C. at the most. 
     
     
         12 . A household appliance according to  claim 1 , wherein the first circuit for the drying medium forms a closed-loop circuit. 
     
     
         13 . A household appliance according to  claim 2 , wherein a critical temperature of the heat exchange medium lies in a range from 90° C. to 115° C. 
     
     
         14 . A household appliance according to  claim 1 , wherein a critical pressure of the heat exchange medium lies in a range from 30 to 35 bar. 
     
     
         15 . A household appliance according to  claim 1 , wherein a critical pressure of the heat exchange medium lies in a range from 33 to 34 bar. 
     
     
         16 . A household appliance according to  claim 1 , wherein the nominal heat of vaporization at the boiling point of the heat exchange medium lies in a range from 175 to 200 kJ/kg. 
     
     
         17 . A household appliance according to  claim 1 , wherein the global warming potential index of the heat exchange medium lies in a range from 2 to 8. 
     
     
         18 . A household appliance according to  claim 1 , wherein the global warming potential index of the heat exchange medium lies in a range from 4 to 6. 
     
     
         19 . A household appliance according to  claim 1 , wherein the heat pump has a nominal cooling power between about 1,500 W and 3,500 W.