Againity’s key to secure a green and clean future with ABB PLCs and drives

Againity’s story begins small, with the dreams of just one man: David Frykerås. With the sole purpose of harnessing the energy lost in industrial processes, he founded Againity – a company that found a way to convert hot water into electricity and district heating with 99% system efficiency.

Their patented design of the Organic Ranking Cycle (ORC) turbines can harness low-temperature heat and convert it into renewable, local, and weather-independent electricity. The heat source can vary, ranging from hot water boilers at heating plants to excess heat generated during industrial processes. Temperature differences as low as 30 degrees Celsius are sufficient for this particular type of ORC turbine to generate electricity. Againity’s ORC turbine system is built in modules from 100kWe up to 560kWe.

State-of-the-art technology in every turbine system

Againity invests in high-quality products, knowing that a single malfunctioning gadget can topple an entire system. ABB’s reputation for cutting-edge products and excellent technical support paved the way for a complete ABB automation portfolio. ABB supplied almost all components in Againity’s ORC turbine systems, ranging from low-voltage products to drives, ABB Jokab Pluto safety Programmable Logic Controller (PLCs), and AC500 PLC with CP600 Human Machine Interface (HMI) products. ABB’s products synergize perfectly, making a complete ABB portfolio the obvious choice.

Two AC500 PLCs are used in the turbine application. One is used for modularity, upgrading previously installed turbines, as well as for data acquisition and secure cloud connectivity. The main PLC controls the ORC generator. The PLCs process approximately 200 signals.

The AC500 Central Processing Unit (CPU) needs to consider numerous parameters to meet the power grid specifications and align the turbine to the grid during start-up. The machine relies on Modbus TCP as its primary communication protocol. It facilitates data exchange between the two AC500 CPUs and connects other components in the cabinet, such as ABB drives, level switches, and other essential equipment.

The machine is equipped with ACS380 machinery drives and ACS580 general purpose drives that control the speed of motors powering water pumps for optimal flow in the overall process. In some applications, an ACS880 regenerative industrial drive is connected to a specially designed ABB motor that acts as a generator driven by the turbine that generates electricity. One CP600 control panel is installed for local operations, and all machines are integrated into the existing on-site SCADA solution, from where most of the supervising is done.

The AC500 acting as a gateway provides real-time data from the machine to a proprietary cloud solution through MQTT protocol. It reads data from the main PLC, drives, and other essential components. All data is processed by the cloud gateway PLC, resulting in data packages that consist of 200 floating-point values. The packages are transmitted to the cloud once per second and are available for further analysis.

“Cyber security is an important aspect in these applications,” Rickard Haglund explains, “and ABB’s PLCs provide the highest level of security.”

Reliable operation of all machine components is of immense importance, as ideally, the turbine should never come to a complete stop. Instead, the components can limit their performance to prevent a shutdown in case the hot water supply runs out. The AC500 CPU makes good use of its integrated floating-point unit as it continuously performs advanced thermodynamic calculations in 6th degree polynomial to guarantee optimal and continuous turbine operation while monitoring over- and underheating.

Rickard adds: “ABB’s programming software provides tools to simplify the programming. The ability to download programming changes online is an important aspect for us. It can be done during operation, and the machines don’t have to be stopped.”

Consequently, Automation Builder is the perfect tool for Againity’s ORC turbines. Advanced calculations are programmed in structured text, and the main program in Continuous Function Chart (CFC), which offers an overview of the entire process.

Againity’s ORC turbines can be deployed in various settings. In treatment plants with residual gas, district heating stations, and many more. Today, there are numerous Againity turbines in operation in Sweden, Norway, Finland, Poland, Estonia, Lithuania, and Greenland.