Electric Drive Radiator Fan Controls Produce Big Savings

Posted on Posted in Prime Power Articles

Electric Drive Radiator Fan Controls

Electric Drive Radiator Fan Controls – Integrated into Paralleling Switchgear

So… I’m selling a power system with a modern, emissions friendly diesel or natural gas generator set.  Boy, have the cooling requirements on these monsters changed over the last 20 years! It used to be the coolant circuit was the coolant circuit – end of story. Now, there are 2 cooling circuits. One for jacket water and one for aftercooler. And each has their own thermal demand needs. Okay, normally this is no problem. I just run all the fans all the time. But…. now I have a job where I’m trying to eek out some extra efficiency percentage points. I don’t need all the fans running all the time. Those are parasitic losses I can’t live with constantly. What do I do now? Call Leman Engineering. We offer smart electric drive radiator fan controls that can vary fan speed or stage fan motors on and off to optimize overall generator set efficiency. And, we’ll treat these two cooling circuits like they were our own. No red-headed step children here!

Potential Savings

There are two markets – standby (emergency) power and prime power.  Prime power means the generator is the sole source of electrical power and runs all the time power is needed.  For example at a rock crusher, this might be 8 hours a day.  At other sites, this is 24 hours a day.  Standby, where essentially the generator never runs, doesn’t justify the investment.  The savings equate to kW-hr savings.

 Diesel generator

7 gallons fuel per 100kW-hr.  Cost of fuel = 7 gallons x $4 = $28 per 100kW-hrs.  On a larger machine (1-2MW), it may use 50kW of radiator power.  Intelligent rad controls can cut parasitics in half.  So that is 25kW of savings.  On a continuous basis, that may be $7 per hour.  Over a month (continuous), that may equate to $5,000 in fuel savings.

Natural gas generator

Similar math, except natural gas may be 1/3 the cost of diesel fuel.  So savings is now $1,500/month-ish.  The thing with natural gas machines is they tend to require more cooling per output kW.  So where the above case might be true for 1-2MW diesels, this swings down to 500kW on the low end for natural gas machines.

The cost of intelligent radiator controls over dumb radiator controls may be a $2500 to $4000 premium.  So on a continuous site, pay back should be 4 months or less.  On an 8 hr/day site, this should be < 1 year for payback.

Next Steps

Let’s talk about how integrating electric drive radiator fan controls into your paralleling switchgear panels might save your customers money!