Returning condensate to the boiler operation is great step toward improving energy efficiency. But how do you know if the costs are justified? An example can demonstrate the process. Table 1 shows the operating criteria for a typical operating steam system.
For the purposes of this example, assume no condensate returned to the boiler plant. In that case:
- (hc - hm)
= Energy Loss per Pound
(180.33 - 23) = 157.33 BTU/lb Energy Loss per Pound
- 44,000 lbs of steam = 44,000 lbs of condensate (90 percent Return) =
- 39,600 lb x 157.33 (BTU/lb) = 6,230,268 BTU
- 6.230268 x $15.30 = $95.32 per hour
- $95.32 x 8,760 (hours/year) = $835,003.20 per year
The above is calculated with no condensate being returned to the boiler, but most industrial plants are returning at least a small percentage of condensate. Each plant should evaluate the cost of failing to return condensate and set forth a roadmap for returning condensate.