Heat Balance Calorimetry


Heat Balance Calorimetry :

It is difficult to quantify jacket Q losses in this kind of calorimetry. This fact makes difficult its utilisation. An alternative approach for measuring the heat generated within the reactor is to determine the total heat balance of the cooling/heating liquid circulating through the jacket: Qtrans=mliq ?cp, liq ?(TJ,in- TJ, out) where cp,liq is the specific heat capacity of the jacket liquid. In this case, Qtrans is independent of both heat exchange area and heat transfer coefficient. However, it depends on the circulation rate liq of the jacket liquid. Heat losses at the outer jacket wall directly influence the heat balance of the circulating liquid. Heat balance calorimetry is relatively slow and insensitive compared to heat flux calorimetry because of the small temperature difference TJ,in ? TJ,out. This also leads to stricter requirements with respect to the accuracy of temperature measurements. To achieve 0.5 W resolution, it is necessary to measure the temperature with an accuracy of about 0.001 K (compared to 0.05 K in heat flux calorimetry for the same resolution). Under typical conditions, energy resolution in heat balance calorimetry is on the order of 2 W, compared with 0.5 W in heat flux calorimetry. 

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