Raising the Bar in Compressor Efficiency
Following the market release of the eDrive range of compressors in 2025, Unicla engineers have continued with extensive testing and product improvements.
A recently completed comparative test to measure the potential gains in isentropic efficiency in the eDrive range has revealed a significant and higher than expected outcome.
The test compares the capacity, performance and efficiency of a new eDrive UD150 to a traditional Unicla belt-drive (oDrive)150 series compressor. The results show that the eDrive UD150 achieved an isentropic efficiency of 82%, an improvement of 24% over the standard 150cc oDrive (belt-driven) model, which measured 66%. Capacity is also improved with an increase of 18.2%.
Technical Director Mark Mitchell said, “from the outset, we wanted our new eDrive compressors to be high performers in tough conditions such as mining, rail, off-highway machinery and transport refrigeration. Our strategy for cooling the electric motor and the compressor is based on our patented air-cooling system that uses a unique thermal jacket over the stator housing, and a special compressor crankcase with cooling fins and an enlarged sump. This latest test, which has been made possible since the completion of our new calorimeter a few months ago, has revealed these excellent results.”
The immediate advantages for HVAC engineers and system integrators are reduced heat load on the condenser and a cooler running compressor to reduce oil fatigue and stress on other components.
These efficiency benefits, in combination with Unicla eDrive firmware, eConnect and eControl, deliver extended life expectancy and reduced life cycle costs (LCC), as well as reduced life cycle climate potential (LCCP).
Test details
The compressor was set up on the new calorimeter at the Unicla SuperTest facility in Australia.
The testing conditions of the calorimeter were set at standard JIS conditions for mobile AC compressor testing, which is 1.81 bar (gauge) suction pressure and 15.2 bar (gauge) discharge pressure, with a 10 K superheat and 5 K subcooling at 1850 rpm.
Results
The graph shows the p-h diagram of the refrigeration cycle of the UD150 on the calorimeter. The testing conditions and results are shown in tables 1 and 2. The compressor capacity is 5.37 kW, the condenser capacity 7.17 kW, and the cooling capacity 5.26 kW. The isentropic efficiency is calculated to be 82% using Equation 1:
Comparing the results
