Dew point is pivotal for compressed air

Refrigerated drying is ubiquitous in Finland and abroad. It is suitable for every size of plant, big and small. Refrigerated dryers are cheap to purchase, maintain and use. Their technology is simple, and the quality of compressed air sufficient for many processes. The pressure dew point in refrigerated drying is more than +3 °C.

Adsorption dryers are a good choice for producing extremely dry compressed air. Adsorption technology can achieve a better dew point than refrigeration, but more energy is spent due to the need for regeneration. Adsorption drying can achieve a pressure dew point of -20, -40 or even -70 °C. With appropriate dew point control, drying can be more energy-efficient, but the chosen regeneration technology also greatly impacts energy consumption.

For example, the air-regenerated Parker MX adsorption dryers used in Sarlin compressed air solutions are rock solid, dead simple and competitively priced. On average, these models consume 10 per cent of the dryer’s air capacity for regeneration (up to 20 per cent at the start of the regeneration cycle) – an important consideration for dimensioning compressors.

The Parker Antares tandem dryers use both refrigeration and adsorption technology. The Antares dryers are more expensive to purchase compared to conventional adsorption dryers, but their operating costs are lower. The need for regeneration is kept low by the refrigeration drying, leading to lower overall energy consumption. The Achilles heel of tandem dryers is their more sensitive technology compared to conventional models.

We have also installed many vacuum-regenerated adsorption dryers for our customers. They use negative pressure and heat for regeneration, produce high-quality compressed air, and are energy-efficient. Vacuum regeneration technology consumes no compressed air, and only needs 30 per cent of the energy of regular adsorption dryers. This translates to significant annual energy savings, but the cost of the equipment is manifold.

We have a long history with vacuum-regenerated FST DTS series adsorption dryers, and we are now expanding our selection with Parker WVM dryers. The DTS and WVM dryers are especially suited for applications that consume more than 100 kilowatts of compressed air.

Our energy-saving models also include Parker HOC dryers. These consume no compressed air nor external energy: they only use the compressor’s waste heat. The challenge for these devices is their complex technology. Their future challenges may also include limited compressor compatibility because most adsorption dryers can accept multiple compressors each.