Danish OEM Advansor has launched an energy-saving ultra-low superheat module for CO2 (R744) refrigeration racks.
The new ultra-low superheat module is developed to allow evaporators to run with very low superheat settings without risking liquid CO2 returning to the compressors. This can raise the evaporation temperature by 4–5°Kelvin, resulting in energy savings of around 10%.
However, depending on the climate and what other technologies are used, the ultra-low superheat module can help deliver even higher energy savings of up to 30%, thus providing the “most energy efficient solution on the market,” Advansor contends in a LinkedIn post. The warmer the ambient climate, the higher the potential savings.
Advansor has been selling the module since 2021 in an ejector-only version. Now the module has been fully optimized for the various applications and is available both with and without ejectors, according to Lisette Lykke Hansen, Strategic Marketing and Digitalization Manager with Advansor.
The Advansor module consists of a suction accumulator, internal heat exchanger and an optional ejector. “The suction accumulator is used to capture any liquid coming back from the evaporators and to separate gas from the liquid,” Advansor said on its website.
The internal heat exchanger’s main function is to evaporate and superheat the gas and liquid CO2 coming from the suction accumulator. A secondary function is to subcool the liquid line, which results in less mass flow and reduces the pressure drop. “The ejector is used to empty the suction accumulator of liquid, and if using a gas ejector, also to move flash-gas from MT compressors to parallel compressors,” Advansor said.
The module can give an additional 7–8% cooling capacity, and if combined with Advansor’s ejector technology the system will provide an additional 5% of energy savings. The ultra-low superheat is designed as a separate module to ensure the most flexibility in placement. The module is available for racks with more than 100kW (28.4TR) cooling capacity, and is available with Danfoss or Eckelmann controllers. It is only available to order together with a rack.
The increased efficiency the module provides can also save significant amounts of money, and the return on investment is around two years, according to Advansor.
A customer that has already opted for an ultra-low superheat module is French retailer Carrefour. They added it to a solution with an Advansor CO2 Cubig rack. The Cubig rack has a 2+1×3 compressor set up and ejector technology. The system delivers 140kW at -8°C (39.8TR at 17.6°F) evaporation temperature, and 30kW at -36°C (8.5TR at -32.8°F).
The combination of the ultra-low superheat module with the Cubig rack enabled the store to save 30% in energy and also reduced the need for defrost by 75%. The combined system has a COP of 4.65.
The high COP is compared to 3.75 for a system with booster solution, 3.98 with booster and parallel compression and 4.18 with parallel compression and high pressure ejectors, according to Advansor.
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