Determining the heat flow emanating from a heat transporting fluid

A method for determining the heat flow (dQ/dt) emanating from a heat transporting fluid (12), which is a mixture of at least two different fluids, and which flows through a flow space (11) from a first position, where it has a first temperature (T1), to a second position, where it has, due to that heat flow (dQ/dt), a second temperature (T2), which is lower than said first temperature (T1), said method comprising the steps of:

• a) measuring the differential temperature (ΔT) between said first temperature (T1) and said second temperature (T2);
• b) measuring the speed of sound (vs) within said heat transporting fluid (12) at a predetermined location of said flow space (11) in the vicinity of said first and/or second position;
• c) measuring the absolute temperature (T) of the heat transporting fluid (12) at said predetermined location;
• d) measuring the volume flow (dV/dt) at said predetermined location;
• e) determining from said measured absolute temperature (T) and said measured speed of sound (vs) the mixing ratio of said heat transporting fluid (12);
• f) determining from said measured absolute temperature (T) and said determined mixing ratio of said heat transporting fluid (12) the density and the specific heat of said heat transporting fluid (12);
• and
• g) determining from said measured differential temperature (ΔT), said measured volume flow (dV/dt), said determined density and said determined specific heat the heat flow (dQ/dt) emanating from said heat transporting fluid (12).