Arrangement in a heat recovery unit

An arrangement in a heat recovery unit adapted for installation in a cooking cupboard or the like space in a dwelling, the unit having within a casing a lamella heat exchanger placed on one corner edge such that two of its surfaces face upwards and two face downwards, said surfaces being the defining surfaces of the openings of passages through the heat exchanger, which has its end walls oriented in vertical planes, whereby said heat exchanger is adapted for heating outside or fresh air serving as supply air by removing heat from exhaust air departing from the dwelling, characterized in that four vertical wall portions, together forming a cross in horizontal section, are adapted above the heat exchanger and connect to it such that two of the wall portions follow a boundary line between both said upwardly facing defining surfaces on the heat exchanger while both the other of the wall portions respectively divide the same defining surfaces so that the four wall portions form four chambers, the heat exchanger having three additional boundary lines between adjacent defining surfaces with each boundary line making a sealing connection with the contiguous wall of the casing, the first chamber constituting an inlet chamber for the exhaust air from the dwelling, the second an outlet chamber for such exhaust air cooled in the heat exchanger, the third an inlet chamber for untreated supply air in the form of fresh or outside air and the fourth an outlet chamber for the supply air heated in the heat exchanger, whereby the heat recovery unit is upwardly connectable to necessary ducting to and from separate rooms in the dwelling and to and from the outside air the heat exchanger also being air-tightly sealed against the casing with its end walls sealingly engaging against the back and front of the casing, whereby said heat exchanger, which is formed as a unit and is insertable and removable by opening or removing the front, is divided into two portions, each of which has a cross-streams relationship between supply air and exhaust air and has its passages for supply air and exhaust air disposed in series with the corresponding passages of the other portion.