Case Study - Ferndale Grain

Business description:  Animal feed processor in Whatcom County.

Original air compressor:  75-hp fixed speed rotary screw.  Data logs revealed this compressor was using 75% of its full load kilowatts to produce 35% of its air capacity.

New air compressor:  67-hp variable speed rotary screw.  Data logs confirmed this compressor uses 45% of its full load kilowatts to produce 45% of its air capacity.

Projected savings:  255,953 kilowatt hours per year, or $20,220.29 at $.079 per kilowatt hour.  (Actual savings were closer to $24,000 per year).

Project cost:  $42,023.75

Power company grant:  $21,899.00

Net cost (not including savings on power consumption):  $20,124.75

Estimated ROI:  1 year (customer reported that actual payback was less than one year.

Details:

Ferndale Grain is a Whatcom County processor of animal feed and in 2001 was a not-so-proud owner of an oil-belching 75-hp air compressor.  Running their operation 24/7 meant that they were spending lots of bucks on expensive compressor oil and maintenance.  Actually, the compressor was not at fault; it was a good machine, just not the optimal machine for this application.

An associated problem was acidic compressor oil being transported down stream.  The maintenance manager reported that he was repairing some stuck or corroded downstream valve almost daily.

Air Compressor Service recommended a newer-technology variable speed air compressor and suitable filtration.  We installed data loggers for a week to capture power consumption data.  Analysis revealed that the 75-hp air compressor was using 75% of its full load kilowatts to produce 35% of its air capacity.  This is a very inefficient ratio.

The new variable speed rotary screw air compressor and its accompanying filters has saved Ferndale Grain approximately $24,000 per year on power bills and it eliminated the constant repair of downstream valves.  According to Curt, the plant manager, the actual return on investment for this project was less than one year.

Could your company benefit from this kind of investment payback?  The first step to finking out is to give Air Compressor Service a call, 888-846-5101.

Case Study - Edco, Inc

Business description:  Steel fabricator in Skagit County.

Original air compressor:  40-hp fixed speed rotary screw.  Data logs revealed this compressor was using 78% of its full load kilowatts to produce 55% of its air capacity.

New air compressor:  30-hp variable speed rotary vane.  Data logs confirmed this compressor used only 49% of its full load kilowatts to produce 61% of its air capacity.

Projected savings:  68,600 kilowatt hours per year, or $4,802.00 at $.07 per kilowatt hour.

Project cost:  $37,993.00

Power company grant:  $18,996.50

Net cost (not including savings on power consumption):  $18,996.50

Estimated ROI:  3.96 years

Details:

Edco, Inc. is a steel fabricator located in Skagit County.  In 2006, one of our system specialists noted that Edco’s rotary screw air compressor was an oily mess.  This is an indicator that the machine may be too large for its application.  Sometimes a fixed speed rotary screw is sized to meet a daily peak demand of short duration.  Unfortunately, the remainder of its operating time is spent producing more air than is needed and belching oil each time it goes off-load.

Our system specialist met with the owner, Mark, and explained the probable cause of the expensive, oily mess.  Mark decided that it would be wise to at least let us prepare an operating profile to accurately assess the situation.

We installed data loggers on the compressor and recorded its electrical power use for seven days.  Then we installed a variable speed rotary compressor and collected data on it for seven days.  The results showed that the 40-hp fixed speed rotary screw was using 78% of its full load kilowatts to produce 55% of its air capacity.  The 30-hp variable speed machine used 49% of its full load kilowatts to produce 61% of its air capacity.  This represents a large savings in power consumption which is a direct result of the variable speed technology that allows the compressor motor to slow down when air demand decreases.

The estimated annual power consumption for the existing fixed speed compressor was 137,100 kilowatts.  Estimated annual power consumption for the variable speed machine was 68,500 kilowatts.  At $0.07 per kilowatt hour, annual savings with the variable speed technology came to $4,802.00.

Based on these measurements, Puget Sound Energy awarded Edco, Inc. a grant for $18,996.50 to help buy the new system.  The combined grant and savings on Edco’s monthly power bill yielded an estimated payback period of 3.96 years. 

Realized savings were even greater, because our expert systems specialist also installed a larger air storage tank that reduced the frequency that the variable speed compressor has to start up.

What happened to the 40-hp oily monster?  We cleaned it up and it is now serving ably as a backup unit for when the variable speed is down for maintenance.

What was Mark’s reaction?  At decision time, “Why wouldn’t I do this?  It makes perfect sense.”  Upon installation, ”It’s so quiet!”