The Heat-to-Power Solution

Subsidiary Specifications

Access Energy, a subsidiary of Calnetix Technologies, sells and services highly efficient and reliable Thermapower™ Organic Rankine Cycle (ORC) systems for identified waste heat sources within industrial applications, such as solar thermal, geothermal, incineration, oil and gas production and fuel cells. ORC systems convert the waste heat into electric power without risking the customer’s production or process.

Solution

Utilizing Calnetix’s existing technologies and design support, a state-of-the-art Organic Rankine Cycle (ORC) system was developed for the purpose of recovering heat from industrial processes. The Carefree Integrated Power Module™ (IPM) is the main component of the closed loop waste heat recovery system that utilizes heat input with temperatures of 180°F (82°C) or higher to generate up to 167 hp (125 kW) of electricity, and this feature differentiates Access Energy from all other waste heat recovery systems. It consists of a high-speed turbine expander and three proprietary technologies from Calnetix – a high-speed permanent magnet generator, low loss magnetic bearings and power electronics in one sealed unit. The Thermapower unit is controlled by an advanced programmable logic controller (PLC), with proprietary control algorithms. This allows for optimal heat utilization at widely different heat source conditions. Magnetic bearings were chosen for this application because of their high reliability, long life, and ability to operate directly in the working fluid a refrigerant without lubrication.

Challenges

There were several challenges on multiple fronts for this end-user product that would span all different types of waste heat applications. One such challenge was the hermetic sealing of the IPM. Since the ORC uses a special fluid for its closed loop cycle, it was paramount that the fluid was not allowed to leak out of the system, even in small quantities. Also, there was no allowable environmental ingress. To achieve this, Calnetix designed a truly seal-less in-line turboexpander generator, also referred as Carefree™ IPM. The Carefree™ IPM has no rotating seals that could compromise the system’s integrity, and this required careful optimization of the active magnetic bearing system with the expander wheel design and the flow path. Another challenge was to make the system work with a variety of evaporator and condenser configurations, so it could adapt to different heat sources. The controls of the system and the sensor configurations were specially designed to be able to achieve a wide range of physical choice of components, topologies and heat-transfer methods.

Global acceptance of the system necessitated the system to be configurable to meet the grid connectivity requirement of individual countries. Special control and hardware features in the Vericycle™ power electronics were designed to enable the individual functionalities. The design has been proven via the wide regional acceptance and installation of the units worldwide, including marine vessels.

In terms of modularity, the system integration team at Calnetix took into account not only industry's best practices and norms, but also the ability of the system to be “manufactured in parts” with local or application-specific content and still have the essential features and capabilities of the system intact. This resulted in a highly modular system that distributors and end-users can configure at site to achieve optimum economical results in each application.

Results

Access Energy has been able to minimize and, in some instances, remove the system’s mechanical and electromechanical losses in a compact modular design. This includes:

• The elimination of a gearbox
• The use of a highly efficient radial inlet expander turbine and generator
• The use of magnetic bearings - no friction and increased reliability
• The use of optimized power conditioning

Access Energy has also formed global partnerships to provide customers with product or regionally focused technical and sales support, streamlining the purchase and installation of Thermapower® and Hydrocurrent® ORC products:

• Daiichi Jitsugyo has exclusive rights to manufacture and market the Thermapower ORC product line for land-based applications in Japan
• Tokyo Boeki Machinery has the rights to manufacture and commercialize the Hydrocurrent product in the global maritime industry
• Daesung Hi-Tech has been appointed by Access Energy as a distributor of the Thermapower ORC125MT system for fuel cell applications in Korea
• Mitsubishi Heavy Industries is a distribution partner for the Hydrocurrent ORC 125EJW shipboard heat recovery system for the global maritime industry