chiller, control, variable speed scroll
For a couple of years already, variable speed compressor technology has become a standard for residential heating and cooling applications. Indeed, as a response to increasing performance requirements, small capacity variable speed scroll compressors optimized for heating and cooling applications were released and progressively adopted on the market. In January 2018, the first tier of the Ecodesign Directive (2009/125/EC) requirements defined for commercial AC chillers will enter into force across European Union. The application of this new regulation will most likely drive the European commercial AC market toward a similar direction than the residential market and a more intensive adoption of the variable speed technology, especially for systems below 400kW rating cooling capacity. This paper presents integrated solutions targeting efficient implementation of variable speed technology in commercial water chillers, allowing system manufacturers to face new regulatory challenges. The considered solution integrates multiple configurations of variable speed and fixed speed scroll compressors, variable frequency drive, electronic expansion valve and control. Compressors envelopes management and protection as well as superheat control capabilities are presented. Seasonal performance simulations have been realized according to EN14825 to quantify the gain of variable speed technology. Laboratory testing has been performed to develop and qualify the considered solution. Testing on a real Air-to-Water chiller has also been realized to fine-tune the control and measure the achieved efficiency levels.