Abstract :
Under no-flow conditions, the energy required to maintain a given temperature on a pipe line is directly proportional to the product of the line temperature above ambient and the time that the temperature is maintained. Since outside ambient temperature varies as a sine curve about the average temperature, the amount of heat required is also continuously changing. On a line traced to prevent freezing manually, controlled, or uncontrolled, steam will expend over 700 percent more energy to maintain the temperature than will electric tracing. With flow in the pipe, the heat wasted by steam can be even greater since the flowing material acts as a heat sink. Since the flow conditions affecting heat loss vary greatly, each installation must be calculated separately. It is quite possible that a steam tracer will expend energy at its maximum rate under conditions that would not require any heat. Steam tracing is more efficiently used on lines requiring a temperature approaching that of the tracing steam.
