Retrofitting air conditioning system with a free cooling chiller

Several concerns including inefficient energy use and growing maintenance costs initiated the need for a chiller replacement at Business Park Vienna, Austria. Having been installed for a long period, and being one of the largest energy consumers in a multi-story building, the existing air-cooled chiller did not operate efficiently under part load conditions such as non-business hours air-conditioning.

The project owner hired Kaltra to review all available options for chiller replacement. Energy analysis and evaluation of ambient conditions existing at the site identified substantial energy savings if the building owner could replace current chiller with free cooling one. Free cooling chiller takes advantage of low external ambient conditions to reduce compressor runtime, saving a significant amount of energy and cutting carbon emissions. The overall lifecycle savings were highest with the Lightstream Freecool chiller when considering energy and maintenance costs over the lifetime of the chiller. This variable speed free cooling chiller exactly matches the capacity under a wide range of loads and temperatures, with mechanical cooling reduced to a minimum.

The pre-retrofit capacity of the chiller was 750kW while the new chiller has a capacity of 900kW, allowed additional areas to be cooled by air conditioning system.

Kaltra provided a turn-key design and startup services, with free cooling chiller installed within the original footprint on the building’s roof. The company worked in tight cooperation with the building owner throughout, providing technical support at every stage of the project.

Performance since project commissioning has resulted in significant energy improvements. Energy analysis of the 3 months before and after project completion shows 80% electricity savings on the chiller.