COM-DRY hybrid refrigeration and adsorption dryers have been designed to continuously separate water vapour from compressed air, thereby reducing the dew point. The drying process consists of two stages. First, a refrigeration dryer removes a large majority of the water and reduces the dew point to PDP +3°C. A further dew point reduction (down to PDP -70°C) is achieved by an adsorption dryer. This dryer is simpler to operate than a conventional heat-regenerated adsorption dryer. At the same time, there is an average compressed air loss of just 4.6%.