Projects // ZIM ORC

ZIM ORC

ZIM ORC is developing a small power plant for the production of electricity, heating and cooling from exhaust heat. The result is a two-stage Organic Rankine Cycle turbine that produces electricity from waste heat in a particularly efficient way, which makes it economically feasible. The scope of the project contemplates building a fully functional small power plant prototype.

Climate change, the need to minimise CO2 emissions and the finite availability of fossil fuels are all driving the undisputed need for maximising the exploitation of waste heat for the production electricity, heating and cooling. The ZIM ORC project, supported by the German Federal Ministry for Economic Affairs and Energy (BMWi) seeks to develop an efficient and economically viable double-staged ORC-facility for the generation of electricity from waste heat. Organic Rankine Cycle (ORC) turbines can efficiently generate direct mechanical work and electricity from low temperature heat. The scope of the project contemplates building a fully functional small power plant prototype. UAS Dortmund is developing the electrical and communication networks and the brain of the installation for optimal demand-based power and thermal control. The University of Paderborn is responsible for the thermodynamic design, Smart Mechatronics GmbH for the control engineering, and Lütkemüller GmbH and Heim Precision Technology GmbH for the mechanics and turbines.

The design of the power plant is based on a number of exchangeable modules—figure 1 illustrates these modules from right to left. Module 1 represents the direct evaporator; module 2, the high temperature system (up to 300°C); module 3, the low temperature system (up to 110°C); and module 4, the condenser. The modular design makes adapting for different waste heat profiles possible; systems can be built with one or two ORC turbines. The system can be configured to work with waste heat input starting at 500 kWth. Currently available solutions require far greater thermal input for economic feasibility.

Development of demand-based control systems for the two-stage installation is particularly challenging. For this purpose, a hierarchical management and control system, based on the Operator-Controller-Module (OCM) from the University of Paderborn is being developed. Control of the first level depends on Paderborn University's thermodynamic data for the various mass cycles, as well as on the thermodynamic behaviour of the devices in the system. Regulation of the second level control circuits comes from a Model Predictive Controller (MPC) and is based on Matlab/Simulink modelling. Level 3 of the OCM model is the communication network and control centre of the machine. It is implemented as a reflective operator for process control and error handling and can automatically correct faults or carry out a controlled shut down if necessary. Finally, level 4 as the cognitive operator contains the self-learning optimisation programme, designed to optimise economic operation of the whole system under varying conditions and with due consideration for maintenance cycles and costs.

The target markets of this technology can be found wherever there is waste heat above 300 °C with more than 300 kWth of power. These levels of available heat are common in biogas power plants and in industry, as well as in solar thermal power generation. The development goal is to generate additional electricity from waste heat at "better than grid parity". This means, 1 kWh from waste heat must cost no more than 0.12 €/kWh, including all costs and without subventions, and with a payback period of less than six years. The prototype will become operational in the spring of 2016, and will be subject to testing and optimisation until the autumn of the same year.

Information on funding and further project participants

Funding code: KF3338401ST4 FH-Dortmund
KF2795210ST4 FH-Dortmund

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