Question

Hot water is often carried by copper pipes in residential homes. Say that we have water flowing from a hot water tank to the shower, and that when the water enters the (pure copper, k = 386 W/m-C) copper pipe (ID = 3/4”, OD = 7/8”), it has Tin = 108 F = 42.2 C. The ambient air temperature is Tout = 19 C. The inner heat transfer coefficient hin = 150 W/m2-C, while hout = 13 W/m2-C. We can at this point calculate the amount of heat loss per length of pipe, q1 = Q1 / L. Now let’s say that we decide to add 1/8” hair felt insulation (k = 0.038 W/m-C), which will give a new heat flux q2 = Q2 / L. What is the ratio of q2 / q1, near the hot water tank where Tin = 42.2 C

Answer 1

DATE Copeen tu otal h2 A2 ohesehish' hs hout side HT.C. 13 w mc Aainside asca of tube inside ious of ube3 22 , 225mm 2 A2 Outside arta-of-tube 0223.87 X16 끄 し2 i m ( As given basis, heat toss per unit length 12 2 -14 4177 W Aaaitian f insulatien insulation insulation - an (73 2) 2 TLKinsulation

DATE.. insulation on L. , 014285 m (0,014285/0·01111 ) 5て53