Pipe Insulation Economies

Abstract

Pipe Insulation Economies is a computer program written in IBM basic to simplify the economic insulation thickness for an insulated pipe. Many articles have been written on this subject, from simple nomographs to a small book written in 1976 by the Federal Energy Administration, called "Economic Thickness for Industrial Insulation (ETI)." This paper is meant to fall somewhere between these extremes without sacrificing the accuracy necessary for economic considerations. Within this text, insulation is dealt with not as a material but as a method to slow heat transfer. To simplify the various mechanisms by which heat is transferred, the variable "thermal conductivity" is used. This is modeled for average insulation temperature. Another variable which has caused problems in the past is the ambient air film coefficient, or surface resistance. This program deals with this coefficient by making an initial assumption, then using an iterative process to refine the actual values before making the economic calculations. The program will use the input data to determine first of all the heat loss in BTU per hr/ft. of pipe. Using this result the lowest annual cost, therefore the most economical insulation thickness, is determined.