| 摘要 |
Method and device for defrosting of an evaporator (1) in a heat pump (2), in connection to an air handling unit (9), and where the air handling unit (9) comprises a controllable heat recovery device (10). The heat pump (2) comprises a refrigerant system (3) with a refrigerant (4) and at least one compressor (5), at least one condenser (6), at least one first expansion valve (7) and at least one evaporator (1). Further the heat pump (2) comprises at least one four-way valve (8) which is arranged in the flow direction after the compressor (5) and before the condenser (6), and the four-way valve (8) is arranged to shift flow direction of the refrigerant (4) in the refrigerant system (3), whereby the refrigerant (4) is sent to the evaporator (1) instead of the condenser (6) without passing the expansion valve (7). The heat recovery device (10) is arranged to recover energy from a first air stream (11) and transfer it to a second air stream (12), and the evaporator (1) is arranged in the first air stream (11), in the flow direction after the heat recovery device (10), and the condenser (6) is arranged in the second air stream (12), in the flow direction after the heat recovery device (10). The invention is characterized by that when frost formation occurs in the evaporator (1), the temperature of the refrigerant (4) through the evaporator (1) is increased, simultaneously as the heat recovery device (10) is down regulated, whereby a simultaneously heating of the evaporator (1) is accomplished, both from inside by the increased temperature of the refrigerant (4), and from the outside by the passing first air stream (11), which temperature increases when the heat recovery is decreased, and thereby the evaporator (1) is defrosted. |
