Compressed air dryers:
August 10th 2009 Innovative technology saves energy and maintenance costs
With immediate effect, users of heatless adsorption dryers can benefit from reduced energy and maintenance costs. The new Ultrapac Classic range from Donaldson makes it possible. This generation of dryers has undergone further development and has new components, which significantly reduce costs. This is in an area of operation where the life-cycle costs of the system soon exceed the initial investment costs of decisive importance.
The Ultrapac Classic range is now equipped as standard with the new Donaldson ultrafilter compressed air filters that comply with ISO 12500-1. In just over a year these energy saving filters have become a well-established product for use in compressed air treatment: due to the filter’s optimised air flow and the effective, applicationspecific filter media, the differential pressure decreases by up to 50 %.
The following example, which is based on a mediumsized Ultrapac Classic dryer, type ALD 850 or MSD 850 illustrates the savings that are made: These dryers are fitted with energy-saving filters (size 1100), producing a lower differential pressure compared to conventional filters (125 mbar less). As a result the power consumption of the compressor is reduced by 1.125 kW.
Based on 8,000 operating hours per annum and a price of 0.08 €/kWh of electricity, this amounts to an annual saving of 720 €.
Using the new filter, energy is particularly saved during drying, in the pre- and after filtration stages. The ease of maintenance has been considerably improved. Both the pre-filter, a coalescing filter from the M range, as well as the V-type after-filter help to reduce service costs due to a longer filter life, while at the same time, their high retention rates increase operational safety. The most economic time for filter replacement is signalled by an LED in the display. During filter exchange another advantage becomes apparent: the filter housing is equipped with a bayonet lock and can be removed easily. This enables the filter to be replaced simply and quickly.
The entire Ultrapac Classic dryer range now takes advantage of this optimised filtration technology. With respect to control technology the standard version, in which case the desiccant regeneration takes place in fixed cycles, is different to those types of dryers that are controlled according to the dew point. Using Ultraconomy control, the dew point values of the treated compressed air at the outlet of the dryer are continually measured and evaluated. The desiccant is only regenerated when a preset dew point has been reached, based on the actual water loading.
The following example shows the possible energy savings that can be made using Ultraconomy control (which is also recommended for retrofitting to other manufacturers’ heatless adsorption dryers). A dryer, designed for 100 m3/h at 35 °C inlet temperature and 7 bar (g) operating pressure, uses approximately 15 m3/h of regeneration air during a fixed cycle. At an average compressed air requirement of 60 %, an average inlet temperature of 30 °C and average pressure of 7.2 bar, the water load still only amounts to approximately 45 % of the maximum value. On average, the dryer with loaddependent control now uses only 6.75 m3/h, therefore saving 8.25 m3/h. Depending on the compressor’s type and condition, this is equivalent to a power consumption of 1 kW. At a full-cost price of 0.02 €/m3 of generated, compressed air and 8,000 operating hours per year, this gives an annual saving of about 1,320 €.
The Ultrapac Classic dryers are available in three ranges, for volume flows from five to 1,000 m3/h. With their compact design and economical operation, these heatless adsorption dryers are a proven “all-in-one” treatment system, suitable for a wide variety of applications.
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