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Psu is the thermal power supplied to the radiator and equals the net difference between the incoming and leaving heat flows as illustrated in figure below. The heat emission Pemission is described by means of the exponential relationship between the radiator performance and the logarithmic mean temperature difference
according to the 2 equations below. The exhaust temperature of the radiator changes according to the supplied thermal power and the heat emission. The exponent nrad in the equation below determines the characteristic of the used end-unit. In case of a radiator it is (1,2 ... 1,34) and a convector (1,25 ... 1,45).
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