An advanced domestic industrial refrigeration CO₂ cascade system with danfoss contribution

Friday, June 1, 2012

Together with you for the green journey

Designed for Yantai FengRun Logistic company, Danfoss offered an advanced industrial refrigeration solution to ensure the smooth operation of a recent installed NH3/CO2 cascade system. Through this proved automatic control solution, this project has achieved customer’s requirement as “fully automated engine control room with minimal human supervision”.

Yantai FengRun project in China adopted a leading CO2 cascade system, which provides cooling to the processing and storage of canned fruit. 

Considering that the project is located in downtown, the customer major priorities were set on achieving both efficiency as well as safety.Standing as the pioneer and leader of industrial refrigeration solutions based on natural refrigerant such as ammonia and CO2, Danfoss offered a comprehensive solution package including Danfoss flagship valves and controls to operate demanding high pressure and low temperature conditions. Aiming to achieve ‘the balance between social responsibility and corporation development’ by the efficient solutions, Danfoss continues offering well proven advanced technologies and reliable products to contribute with the development of the Chinese refrigeration industry.

System safety design

Since it is located in the downtown, the project is applied with a common solution in European countries as NH3/COcascade system for considering the safety factor to strictly limit the ammonia charge. The NH3/CO2 system features, one high temperature system and one low temperature one. As a result, ammonia can be reduced to 10% of the total charged used in standing alone of the ammonia systems, which ensure a more safe environment for the cold storage and food production. ON the CO2 side, Danfoss valves rated at a MWP (Maximum Working Pressure) of 52 bar made it ideal to fulfil the plant design conditions. Under the high pressure conditions, the system was furnished with the modular valve stations, like Danfoss ICF control solution and ICV industrial control valve, to ensure a good operation, and simplify the maintenance and service of the system.

System stability design

As required by the customer as "fully automated engine room", the precise liquid level control solution that Danfoss provided can guarantee a good stability for the system. Liquid level control is considered key to offer a stable and reliable liquid feed and exert a big influence on the operation and efficiency of the system. Due to the low dielectric constant of the CO2 refrigerant and the complex condition in the liquid separator, traditional capacitive level probes are not accurate and present erratic readings during operation. Danfoss newly introduced liquid level sensor AKS 4100(U) has been applied in this project, and achieved a precise and reliable liquid level reading by its new TDR (Time Domain Reflectometry) technology. As a result, the system can control opening of the Danfoss ICM motorized valve to enlarge the setting range of the capacity. Meanwhile, this arrangement is more flexible and compact, and easy for the remote control, which is the precondition of the unattended station.

System economical design

For the efficiency saving consideration, the project is installed with CO2 compressor (manufactured by Yantai Moon) to operate the hot gas defrosting. Successfully applied in the solution, Danfoss ICM series motorized valve is used to control the defrost process from hot gas supply and suction line pressure equalization once the sequence is terminated. FengRun's NH3/ CO2 cascade system is in a smooth operation, and the system already reduced electricity usage for refrigeration by around 10% every year for the company.

Danfoss industrial refrigeration national sales manager Mr. Yan Lixin has expressed "I'm proud of the successful cooperation that Danfoss automatic control solution on the Yantai FengRun project. As a leading company in CO2 refrigeration technology, Danfoss would like to share its rich experience and cases from Europe to Chinese partners. I can clear see that CO2 solutions will have a good future in China refrigeration related industries, and we Danfoss will contribute more to this field with info sharing, project instruction, system guidance and product supply."

Danfoss industrial refrigeration national sales manager Mr. Yan Lixin, the project owner of Yantai FengRun project

As a kind of greenhouse gas, the reduction of the CO2 discharge can release the greenhouse effect. Meanwhile, CO2 as a natural refrigerant applying in the refrigeration field bears a long history. Compared with the traditional refrigerant, CO2 can represent the trend of the future refrigeration as its environmental and safe factors. 100 years ago, CO2 has once applied in the ice machine. A century later, CO2 has re-entered people's view based on its excellent advantages.

To promote CO2 as a natural refrigerant and achieve the "Twelfth five-year" plan of energy saving and emission reduction, Danfoss industrial refrigeration offered two series of "CO2 road show" to the Chinese peers in late 2011 and early 2012. Two phases of road show routed over 15 cities with over thousands attendees, Danfoss also successfully promote their solutions in energy saving, safety and environmental friendly of CO2 refrigerant through this event.