Cooling heat duty curve

Fig. 5. Simple heat-exchange network where stream C is heated, and streams A and B are cooled (a) schematic (b) temperature—cumulative duty curve...

Using the grand composite curve, the loads and temperatures of the cooling and heating duties and hence the COPhp of integrated heat pumps can be readily assessed. 

The mean temperature differential (MTD), given true cocurrent or countercurrent flow, is independent of the type of apparatus and is easily calculated. A straightforward calculation gives the amount of heat that must be removed to cool the gas to any given temperature inside the exchanger. This information is often displayed in a duty curve, such as that of Fig. 9.3. This is a companion to the example given below, and it shows the temperature of the gas as a function of the percentage of the total... 

S) For vaporizing or condensing service, n heating or cooling curve is required, listing temperature, pressure, weight fraction of vapor (or vapor and liquid flow rates in th/hr) and physical properties of vapor and liquid at various equal increment of heat duty,... 

Figure 12.31 Heating and cooling curves of an intermittent duty motor...

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