Tests find under performance in CO2 gas coolers

FRANCE: Eurovent Certification has found wide discrepancies of up to 31% between the manufacturers’ claimed performance and its own test results of uncertified CO2 gas coolers. 

The Paris-based independent certification body found deviations between claimed and expected performance across all capacity ranges of 48 uncertified products. Using data sheet analysis, the study compared the claimed heat rejection of the gas coolers under several market operating conditions.

Products were chosen from a sample of uncertified manufacturers, active within the European market and with a range of capacities from ≤50kW to >250 kW. 

The lowest found deviation showed a 12% underperformance and a 23% average underperformance across all 48 products. 

Europe has seen a sharp rise in CO2 refrigeration systems and, while the problem of underperformance is not exclusive to CO2 gas coolers, Eurovent Certification says the current technology is less mature than the HFC counterparts it is replacing. 

Also, the self-assessment of expected performance and the testing of heat exchangers is complex, with a high range of variables impacting on performance. Added to this, says Eurovent Certification, CO2 has its own unique properties, which require a unique testing process and correction factors to achieve accurate results. 

“This makes CO2 systems particularly vulnerable to discrepancies between expected and declared performance data,” it says. 

Eurovent Certification evaluated the claimed heat rejection performance at standard condition A5 (SC20) and conditions C5, C3 and C2, which relates to products installed in central and northern European climates.

“All players in the refrigeration industry need access to accurate and precise product performance data. However, declared data is not always correct,” Eurovent Certification states in a new white paper Broken Trust – energy efficiency and the refrigeration industry.

“There is no legal requirement to have performance data independently or impartially verified, and so manufacturers can conduct their own product performance assessments and tests. Self-assessment testing facilities, test equipment calibration, processes and procedures can vary from manufacturer to manufacturer, allowing for bias and disparity in declared data.”