Kitchen extractor hood with thermal energy recovery

Abstract

The kitchen extractor hood ( 110 ) is provided with means ( 38 ) for generating a first flow (A, B) of a gaseous mixture taken from the internal environment ( 51 ) in which the hood ( 110 ) is located and releasing it into the external environment ( 52 ). The hood ( 110 ) is also provided with means ( 28 ) for generating a second flow (C, D) of a gaseous mixture taken from the external environment ( 52 ) and/or from the internal environment ( 51 ) and releasing it into the internal environment ( 51 ), as well as with means ( 10 ) for recovering part of the thermal energy contained in the first flow (A, B) and transferring it to the second flow (C, D). The means ( 10 ) used to recover thermal energy comprise a recovery device ( 14 ) comprising in turn a heat exchanger of the heat pipe type ( 16 ), featuring an evaporation section ( 14 E) dealing with the first flow (A, B) and a condensation section ( 14 C) dealing with the second flow (C, D).

1 . A kitchen extractor hood ( 110 ), comprising a first suction device ( 38 ) for generating a first flow (A, B) of a gaseous mixture taken from an internal environment ( 51 ) in which the hood ( 110 ) is located and releasing it into the external environment ( 52 ), a second suction device ( 28 ) for generating a second flow (C, D) of a gaseous mixture taken from at least one of the external environment ( 52 ) or from the internal environment ( 51 ) and injecting it into the internal environment ( 51 ), a thermal energy recovering part ( 10 ) contained in the first flow (A, B) and transferring thermal energy to the second flow (C, D), wherein the thermal energy recovery part ( 10 ) comprises a heat recovery device ( 14 ) comprising a heat exchanger of a heat pipe type ( 16 ), having an evaporation section ( 14 E) for the first flow (A, B) and a condensation section ( 14 C) for the second flow (C, D), and upstream, with reference to the second flow (C, D), of the condensation section ( 14 C) there are provided second flow (C, D) filters, and wherein the heat recovery device ( 14 ) based on the heat pipe exchanger ( 16 ) comprises:
 a plurality of equal pipes ( 16 ), arranged parallel to but spaced from each other, the pipes ( 16 ) each being hermetically closed at two ends thereof and containing a refrigerating fluid in the saturation condition;   a diaphragm ( 22 ) perpendicular to and not interrupting the pipes ( 16 ), which separates the first flow (A, B) from the second flow (C, D), separating the evaporation section ( 14 E) from the condensation section ( 14 C) of the heat exchanger ( 14 ).   
     
     
         2 . A hood ( 110 ) according to  claim 1 , wherein the thermal energy recovering part ( 10 ) contained in the first flow (A, B) also comprises a second heat recovery device ( 15 ) comprising a crossflow heat exchanger, in which the second flow (C), upstream with respect to the condensation section ( 14 C), laps an outside of an exhaust duct ( 34 ) in which the first flow (B) passes through downstream with respect to the evaporation section ( 14 E), the exhausted duct ( 34 ) having walls thereof made of a good heat conductor material. 
     
     
         3 . The hood ( 110 ) according to  claim 1 , wherein the first ( 38 ) and the second ( 28 ) suction devices respectively are mounted upstream or downstream, with reference to the direction of the respective flow (A, B; C, D) thereof, respectively of the evaporation section ( 14 E) and of the condensation section ( 14 C) of the heat recovery device ( 14 ) based on the heat pipe exchanger ( 16 ). 
     
     
         4 . The hood ( 110 ) according to  claim 1 , wherein upstream, with reference to the first flow (A, B), of the evaporation section ( 14 E) there are provided the first flow (A, B) filters of the type used in hoods. 
     
     
         5 . The hood ( 110 ) according to  claim 1 , wherein the second flow (C, D) is intercepted by a shutter ( 40 ) which is closed whenever it is not desired to have thermal energy recovery or during summer operation of the hood ( 110 ). 
     
     
         6 . The hood ( 110 ) according to  claim 1 , wherein a position of the diaphragm ( 22 ) is determined as a function of a ratio between volumetric rates of the first flow (A, B) and of the second flow (C, D), of a thermal exchange surface of the heat exchanger ( 14 ), and of a tilt of the pipes ( 16 ) of the latter. 
     
     
         7 . The hood ( 110 ) according to  claim 1 , wherein the pipes ( 16 ) are arranged in a plurality of superimposed ranks. 
     
     
         8 . The hood ( 110 ) according to  claim 1 , wherein, in order to increase a thermal exchange surface, the heat recovery device ( 14 ) based on the use of heat pipe ( 16 ) comprises a sequence of fins ( 24 ) equally spaced from each other and perpendicular to the pipes ( 16 ), such as not to interrupt their continuity. 
     
     
         9 . The hood ( 110 ) according to  claim 1 , wherein the heat recovery device ( 14 ) is removable. 
     
     
         10 . The hood ( 110 ) according to  claim 1 , wherein the refrigerating fluid contained in the pipes ( 16 ) is of the type used in refrigerators. 
     
     
         11 . The hood ( 110 ) according to  claim 1 , wherein there are provided means for varying a tilt of the pipes ( 16 ) of the heat recovery device ( 14 ).