Client: DESY
Type of works: retrofit of existing cooling towers using 15 Jaeggi hybrid dry coolers.

The DESY Hamburg facility had multiple cooling needs including the PETRA III X-Ray, the DESY II experimental circle particle accelerator and its magnetic circuits, and the facility’s centrifugal chillers. To meet these diverse demands the company installed fifteen Jaeggi hybrid dry coolers in various sizes with an aggregate cooling capacity of 25MW (5,687 evaporative tons).

Using state-of-the-art Jaeggi technology, closed-loop cooling cycles were created to minimize fouling, reduce cleaning, improve efficiency and reliability ,and reduce water costs. The majority of the towers installed were standard configuration coolers with heat exchangers made of copper tubing and aluminum fins.

One unique unit, however, was equipped with both the heat exchanger tubing and fins made of aluminum.

The research center uses only fresh water with no antifreeze in their cooling towers, so Jaeggi hybrid dry coolers were specially modified to safely operate under these requirements. Therefore, motorized dampers on the suction side and fan shutters on the discharge side were installed on all units.

For optimal water conservation and reduced operating cost, the heat exchangers of the hybrid dry coolers were connected in series of dry and wet mode. This configuration allowed for a very precise set point control and for a dry mode operation up to 25°C outside air temperature.
This limited the annual need to operate in wet mode to a maximum of approximately 200 hours.

Individual operation for DESY’s 15 units is handled by the HybriMatic^® single-cooler control with Siemens components. All units are subordinate to the HybriMaster^® control. Jaeggi’s proprietary control technology allows the Jaeggi hybrid dry coolers installed at the DESY Research Center to use up to 80% less water and significantly less energy than traditional towers. DESY has reduced their operating costs while improving the efficient use of resources.