ESK Schultze: extended oil management range for transcritical CO₂ units

ESK components for subcritical applications have been used in the past by manufacturers, system installers and universities for CO₂ pilot refrigeration systems and laboratories. In Denmark, Norway and Finland, ESK-oil control systems for parallel compressor operation work successfully with CO₂ in both supermarket and food freezers applications. Based on this long experience with subcritical CO₂ systems, ESK Schultze has been offering oil management components for transcritical applications since 2007. Continuously working on new developments, ESK Schultze has now extended its transcritical oil management system with new oil reservoirs, oil level regulators, pressure valves as well as new suction line accumulators.

ESK Schultze’s solutions for transcritical applications

The oil management system for transcritical CO₂ units includes the following components:

• Oil separators for transcritical CO₂ application series BOS2-CDH (see previous articles)
• Oil reservoirs for transcritical CO₂ application OSA-5-CDH and OSA-12-CDH (new, see details below)
• Suction Line Accumulators for transcritical CO₂ application FA-12U-CDH, FA-16U-CDH, FA-22U-CDH (new, see details below)
• Oil level regulators for transcritical applications, ERM2-CDH (pre-series)
• Pressure valve RV-CDH-2F-2,5 (pre-series)

All units are designed and manufactured according to European Pressure Vessel Directive.

Oil Reservoirs for transcritical CO₂ application

Any refrigerant trapped within the oil in the oil reservoir is boiled-off and the oil is cooled and kept available. ESK-oil reservoirs for transcritical CO₂ application are available with 5 litre and 12 litre volume and equipped with three sight glasses without float ball. The pipe connection for the oil inlet / outlet are designed as welding and Swagelok pipe connection. The connections for the safety valve, the electronic level control and for the filling operation are designed as NPT screw connections.

Basic specifications

• Max. admissible operating pressure: 130 bar
• Admissible operating temperature: -10 to 100°C
• Test pressure: 185 bar
• Design according to AD-rules
• Excellent reliability + quality
• Easy installation

Suction Line Accumulators for transcritical CO₂ application

ESK suction line accumulators protect the compressor against liquid hammer and its subsequent damage.

Basic specifications

• Max. admissible operating pressure: 100 bar / 75 bar
• Admissible operating temperature: -10°C to 100°C / -10°C to -50°C
• Test pressure: 145 bar
• Design according to AD-rules
• Suction line accumulators are made of stainless steel
• Excellent reliability + quality
• Easy installation

Future transcritical projects

Right now, ESK Schultze is developing an electronic oil level regulator and a pressure valve in order to offer a complete oil management system for transcritical CO₂ units. First pilot installations are already working with a complete oil regulation system.

ESK Schultze’s solutions for subcritical applications

Since 2004 ESK Schultze has been successfully developing and selling subcritical R744 components for refrigeration, air conditioning and heat pumps. These solutions are already proven and established on the market and include the following components:

• Oil separators
• Suction line accumulators
• Filter driers
• Strainers
• Oil reservoirs
• Oil level regulators
• Discharge line mufflers for Ps = 45 bar

The product range for CO₂ subcritical application has been extended by the new CDM series. The components of this series, such as oil separators, oil reservoirs or filter driers, are suitable for a max. operating pressure of 60 bar. More information will be published soon on R744.com.

About ESK Schultze

ESK Schultze GmbH & Co.KG was founded in 1960 as a commercial enterprise. Since 1984, the company has been developing and manufacturing components for the refrigeration, air-conditioning and heat pump industry under the brand name ESK.