Industrial Utility Efficiency

# Printing Facility Reduces Air Demand

### Printing Facility Reduces Air Demand and Avoids a \$34,000 Capital Expenditure ### Introduction This article will focus on a compressed air system assessment done at a printing facility in Canada. The energy costs at the time, in Manitoba, were \$0.025 per kWh and the installation was of just 65 horsepower of air compressors.  The compressed air demand was very high on the system which was causing pressure problems and as a result the company was planning the purchase of a new 50 hp air compressor and air dryer to meet demand.

 "Total energy savings were \$23,800 per year." - Ron Marshall, CET, CIM, Manitoba Hydro The portion of the system assessment we will review is the work done to understand the demand profile and constituents of compressed air demand. The results were significant in that they not only reduced air demand, but more importantly in this case, helped the facility NOT to have to purchase an additional air compressor. Purchasing an additional air compressor would have created an unnecessary \$34,000 capital expenditure. Further to this,  the study also helped identify and eliminate electrical demand caused by an boiler style humidification system and avoid proposed air powered humidification load being placed on the compressed air system. Due to space limitations, this article focuses only on the “constituents of demand” segment of the compressed air system assessment.

### Constituents of Compressed Air Demand

The plant had two lubricated rotary screw type compressors and refrigerated dryers installed; one 50 horsepower (hp) and one 15 hp unit.  In general, the piping system consisted of a mixture of loop and radial feeds appearing to be adequately sized, in most instances, based on pressure logger data collected during the study.

A detailed end use assessment was performed to determine the makeup of the compressed air demand. Some of this demand was deemed as "inappropriate use" that could be reduced or eliminated by applying efficiency measures. The following is a constituents of demand table which takes into account the potential reductions in air demand identified during the plant study. The demand reductions were to be achieved by reducing blowing and by eliminating existing humidification load and other poor air demands.

A further examination of existing electric boilers operating throughout the plant showed that their total energy consumption was 486,900 kWh per year.  These systems were slated for conversion to compressed air powered nozzles. Replacing them instead with a high-pressure water system was projected to eliminate future compressed air cosumption by 59,000 kWh and avoid further compressed air demand.  Total energy savings of the final conversion would be worth an estimated \$30,000 per year – plus the cost avoidance of adding a new air compressor. ### Energy Savings and Cost Avoidance Reducing the constituents of demand played an important role in reducing the compressed air energy consumption by 115,000 kWh. Replacing the boiler system with a high-pressure water system saved 482,900 kWh. Total energy savings were \$23,800 per year.  Deferring the purchase of the new air compressor avoided a \\$34,000 capital expenditure.

Note: Savings due to conversion of the existing units are included in the air system calculations

### Conclusion

Many owners of compressed air systems with less than 100 horsepower of installed capacity do not think they can achieve substantial savings with a compressed air system assessment.

Whenever a “smaller” system is at its’ limit and a new compressor purchase is being planned, we highly recommend a system assessment before making any decisions.  This printing facility received an unexpectedly positive result from the assessment, which helped their financial performance.

® Manitoba Hydro is a licensee of the Trademark and Official Mark.

For more information visit the Compressed Air Challenge® website or contact Ron Marshall, Marshall Compressed Air Consulting, tel: 204-806-2085, email: ronm@mts.net.