kappa] = the effect of the

mean temperature difference between stations B1 and H7;

flowing] = log

mean temperature difference under flowing conditions

lm]) is the logarithmic mean temperature difference, [A.

Figure 5 the variation of logarithmic mean temperature difference with velocity of air passing through the evaporator with different test conditions for R22 and M20 refrigerant mixture.

2]/K) HC Hydrocarbon HFC Hydroflurocarbon k Thermal conductivity (W/m/K) L Length of the tube (m) LMTD Logarithmic mean Temperature difference (K) m mass flow rate [m.

The heat transfer equation, using the

mean temperature difference to each independent tube applied to pure cross-flow type heat exchangers (Domanski 1989), is shown below.

Plateflow is said to offer true countercurrent flow, maximizing

mean temperature difference between the fluids.

For the calculation of the heat transfer, a new equation is used to calculate the mean temperature difference under consideration of the dissipation.

The definition of the heat transfer coefficient based on the logarithmic or arithmetic mean temperature difference between the melt flow and the barrel wall is no longer useful for the flow field inside the screw channel because of the temperature rise of the melt due to dissipation.

In this work a model is developed to calculate the mean temperature difference under consideration of the dissipation.

The

mean temperature differences between top and bottom varied by freezer capacity.

In the analysis of transfer functions, Fahlen (3) has motivated the use of arithmetic instead of logarithmic

mean temperature differences ([theta] is used for temperature difference between two media and [DELTA]t for temperature change of one medium).