Hybrid Cooler HK The hybrid water cooler is a patented process and product of E.W. Gohl GmbH. It distinguishes itself through an environmentally friendly method of operation due to the combination of the advantages of wet-dry cooling. Due to the control being dependent on the cooling load, a saving of additional water of up to 75% is achieved as compared with the pure wet cooling. Plume formation is not an issue for the hybrid cooler. In addition, it is very safe to use in the winter and extremely easy to maintain due to its low construction height. This and many other advantages make the decision easy for our customers.