PROSETANSE PENGHEMATAN ENERGI PANAS YANG DI TRANSFER MELALUI PIPA BERD/NDING TIPIS TANPA CAT DAN DENGAU LAPISAN CAT

Abstract

Pipe Transporting 4 fluid are lagged for threereasoris : a. To reduce transfer and los of energy b. To Prevent The fluid freezing c. To safeguard personnel If to safe guard is the reaason for lagging, then minimal amount of insulation is applied, consitent with safety considerations. For reason to reduce transfer and loss of energy and prevent the fluid freezing, the whole life cycle cost should be considered : i.e., the savings Affected by reducing the energy losses and cost of insulation should be compared. Lagging is applied, sufficient to Produce a credit balance. Energy loss depends on : - The difference in temperature between the steam inside and the air outside the pipe - the pipe thickness The velocity of the steam in the pipe - The state of the air surrounding the pipe (srill or in motion) - condition of the steam (saturated or super heated) The loss of energy take place partly by convection, but mainly by radiation. It is greater when the steam is flowing through the pipe and not quiescent. If saturated steam is used, A film of water is deposited on the inside of the pipe. This aids the transfer of energy, and more energy cost as A result. The fact that the use of superheated steam permits A. Reduction of temperatur without depositing moisture account for some of the ecomo my attending its use. In the majority of cases of heat transmision that arise in engineering practice, heat flows from some medium through a solid retaining wall into some other medium. Percentage saving of energy due to lagging is : Energy loss (unlagged) - Energy loss (lagged) Energy loss (unlagged)