THE European Union’s F-Gas Directive goes into effect in July 2007. Among other things, it stipulates that refrigeration and air conditioning facilities be regularly maintained and checked for leak tightness by qualified personnel. All service work must be continuously documented and traceable. The object of these regulations is to reduce the emission of greenhouse gases.
“Numerous operators, contractors and component manufacturers are already setting a good example by favouring natural refrigerants such as ammonia, carbon dioxide and hydrocarbons,” comments Monika Witt, chair of Eurammon, the European Initiative for Natural Refrigerants. 'This is especially sensible when dealing with building air conditioning, since no one wants to live without air conditioned rooms anymore. The increased energy demands associated with air conditioning may be met with facilities that use natural refrigerants. Their great efficiency makes them a good choice here.'

Economy as the deciding factor

One leading German sweets manufacturer has taken a very forward-looking approach. The company erected a new production building on its factory premises in Halle/Westfalen. Following a detailed cost effectiveness analysis, the manufacturer decided to air condition the premises using an ammonia system. At the heart of the facility installed by Dresen + Bremen are four variable-speed rotary screw compressors with a total output of 2.8MW. Plate heat exchangers, operating with gravity fed ammonia, are used with propylene glycol as a secondary refrigerant. The evaporation temperature is 3°C, the condensation temperature 33°C. The waste heat from the rotary screw compressors is used to heat process water, The cooling plant is housed in a steel engine room on the roof of the production hall.

The Baden-Württembergische Landesbank in Stuttgart, Germany has been continually upgrading its air conditioning system since the late 1990s. At the moment, eight Grasso liquid ammonia chillers supply cold water at 6°C in summer and 12°C in winter. The water is used to air condition the office space and cool the mainframe computers. The refrigeration machines are located on the top floor of the main building, while the Evapco evaporative condensers are mounted on the roof of the technology centre. Compact construction limits the ammonia charge per chiller to approximately 300kg. One special feature of this cooling facility is free cooling. Those parts of the facility containing ammonia are housed in gas-tight cubicles and are monitored by sensors. The facility has a total refrigeration output of over 15MW.

Cooling office buildings

Roche Products, a global health care corporation, relies on a combination of ammonia and hydrocarbons. Its pharmaceuticals division, where products used in the prevention, diagnosis and treatment of disease are produced, is located at its 22,000m2 UK headquarters in Welwyn Garden City. Star Refrigeration supplied two 930kW ammonia chillers which are mounted on the roof of the building to provide air conditioning for the offices.

In the summer the ammonia chillers can offset part of their heat rejection load by using borehole water pumped through an ancillary heat exchanger. This reduces the discharge pressure of the condensers and effectively increases the facility’s efficiency. Three additional chillers run on hydrocarbons and cool the computer server rooms, with refrigeration output of 130kW each. All five chillers are equipped with alarms and sensors to monitor leaks.

The 5,000m2 Saab headquarters in Linköping, Sweden uses four, remotely-sited, 2MW liquid ammonia chillers supplied by York Refrigeration. The administrative buildings are supplied with cold energy via an extensive network of pipes that conduct cold water at 8°C (summer) and 12°C (winter). This allows for keeping all rooms at a pleasant temperature of 20°C to 23°C regardless of the time of year.

A future-proof investment

“The experiences operators, contractors, and suppliers have gained with natural refrigerants, are positive down the line,' says Eurammon’s Monika Witt. 'They represent an easy-to-handle, environmentally friendly solution in refrigeration and climate technology. But above all, natural refrigerants are a safe investment. No matter how the European Union’s review of the F-Gas Directive turns out, natural refrigerants won’t be affected.”

Eurammon

+49 (0)69 6603-1277