Patent ID: 8100167

Claim:
A method for detecting an abnormality of a heat exchanger exchanging heat between a first fluid flow of a refrigerant flowing in a conduit and a second fluid flow flowing along a flow path, said conduit and said flow path each having an inlet and an outlet, said method comprising the steps of: establishing at least one parameter representative of the temperature conditions of the heat exchanger; establishing a second fluid inlet temperature; establishing a parameter indicative of an expected heat exchange between the heat exchanger and the second fluid; calculating an estimated second fluid outlet temperature; and employing the estimated second fluid outlet temperature for evaluating the heat exchange between the first and second fluids by comparing the estimated second fluid outlet temperature, or a parameter derived therefrom, with a reference value; the calculating step further comprising establishing the estimated second fluid outlet temperature from at least one parameter representative of the temperature conditions of the heat exchanger, the second fluid inlet temperature and the parameter indicative of the expected heat exchange; establishing a first heat rate of the first fluid using a specific enthalpy change of the first fluid across the heat exchanger, the specific enthalpy change being obtained from the group consisting of a log p, h-diagram of the refrigerant, a p,h-chart of the refrigerant, a p,h-table of the refrigerant, and an equation of state for the refrigerant; using the estimated second fluid outlet temperature to establish a second heat rate of the second fluid; and evaluating an energy balance of the second heat rate of the second fluid by comparing the second heat rate of the second fluid to the first heat rate of the first fluid.