Influence of a leak on a liquid cooling chiller performances working with a non-azeotrope mix.

The F-Gas regulation (2014) requires gradual decrease of GWP for all refrigerants which allows the development of new blends placed on the market. Many of these blends have an important glide, which is propitious for a modification of the composition in the circuit (evaporator, condenser, leakage…).

The composition of circulating blend becomes a major parameter in the comprehension of results for any study. Thus, a non-intrusive method for composition measurement was developed. This method is based on online optical measurement with a Fourier Transform Infra-Red spectrometer. After a careful calibration and setting up a statistical model based on sample spectra, the measurement of composition is nearly real time.

For this study, a chiller working with blend R-455A is used for a series of leakages and recharges, in parallel the performance and composition is measured between each step. For the R-455A in this set-up with direct expansion, the compositions and the performances stayed constant. Although the study is still in its beginning, the results obtained are encouraging.