The second question is: What type of energy is being saved? The two main classes
are thermal energy (heat, which may be provided either directly from a fired heater or
indirectly in steam or some other heat transfer medium) and electric power. Many sites
have steam at several different pressure levels, so it is important to identify which level is
impacted. In some cases, the steam demand is impacted at more than one pressure level,
as illustrated in the isomerization splitter example earlier in this chapter.