TOTAL AREA TARGETINGIn this part we will explore ways to predict the total area of a network without the need to explore specific designs. Because A=Q/(U*∆Tml), one can calculate the area easily in the following situation. TQ∆Tml=TH1TH2TC1TC2(TH1-TC2)-(TH2-TC1)(TH1-TC2)(TH2-TC1)ln∆H
TOTAL AREA TARGETINGSince area=Q/(U ∆Tml), the composite curve diagram provides one way of estimating the total area involved. Isolate all regions with a pair of straight line sections and calculate the area for each. Cooling water Heating utility, steam or furnace. A1A4A5A6A3A2The above scheme of heat transfer is called VERTICAL HEAT TRANSFER∆HT
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EXERCISECalculate the values of Q in each interval and estimate the corresponding area. Use U= 0.001 MW m-2 oCFurnace (300 oC)Obtain the totalarea estimateCooling Water 230180140202502008040∆T= ∆TminPinchQ1Q2Q6Q3Q4Q5∆HT