摘要 |
A method for controlling a supply of refrigerant to an evaporator (2) of a vapour compression system (1), such as a refrigeration system, an air condition system or a heat pump. The opening degree of the expansion valve (3) is controlled on the basis of an air temperature, Tair, of air flowing across the evaporator (2), and in order to reach a reference air temperature, Tair, ref. The opening degree is set to the calculated opening degree, overlaid with a perturbation signal. A temperature signal, S2, representing a temperature of refrigerant leaving the evaporator (2) is monitored and analysed. In the case that the analysis reveals that a dry zone of the evaporator (2) is approaching a minimum length, the opening degree of the expansion valve (3) is decreased. This provides a safety mechanism which ensures that liquid refrigerant is prevented from passing through the evaporator (2). |