Energy efficiency Heat
Energy efficiency Heat recovery From machine to system solution Double-stage compressed air packages with heat recovery Lothar Stoll Energy balance of a typical dry running single-stage screw compressor Thanks to open system integration, modular basic components as well as variable mechanical and electronic interfaces, the oil-free doublestage AERZEN screw compressors of the 2C series offer the highest functional adaptability for different drive and control concepts. In combination with customised systems for heat recovery, the individually designed compressed air packages become real energy savers and are part of a system solution. A large amount of heat energy is generated during the production of compressed air. If this process heat is recovered by means of heat recovery for further operating processes such as water heating, drying processes or preheating of burner air, considerable energy savings, emission and cost reductions can be achieved. With high-performance compressor technology and customised heat recovery systems, AERZEN offers just the right answer. The result: maximum resource efficiency and cost-effectiveness. One example are the 2C series doublestage screw compressors with heat recovery from the RKR Gebläse und Verdichter GmbH, a 100 % subsidiary of AERZEN and the specialist for double-stage compressor solutions within AERZEN Group. These double-stage compressor solutions are turned into an innovative system solution of the customer application by the AERZEN customer 20 GREEN EFFICIENT TECHNOLOGIES 2023
Energy efficiency Heat recovery Fig. 1: The traditional machine perspective focuses "only" on the inlet and outlet conditions (All images: AERZEN) consulting and engineering competence of RKR. One application in practice First of all, everything revolves around the application and use case, in this example the use of dry compressed air in the quenching and tempering process of steel production. A clear understanding of the application and the conditions of use, especially the different environmental conditions and operating points in the operating/annual cycle, is crucial. This shows that in addition to the machine-specific operating situation, such as full and partial load, the system existing outside of the compressor technology, for example a seasonal connection of refrigeration dryers or absorption dryers, must also be considered in a superordinate manner. From compressor to system solution While the traditional machine perspective focuses “only” on inlet and outlet conditions, understanding the application is a MUST for the system solution. Only a few key data apply to the machine as a black box, as the diagramme shows. In the system, on the other hand, other perspectives and requirements are coming along - namely the customer’s overall process and, in doing so, the aim of using the thermal energy contained in the compressed gas as a source for heating process water. So, it is no longer exclusively about a gas at the transfer point of the machine (see diagramme machine perspective), but rather about the question of how the greatest possible thermal energy can be supplied to an overall system, i. e. a process. An artifice for innovation A large part of the electrical drive energy in air-cooled or water-cooled oil-free compressors is bound in the gas flow as heat. Now the trick: the temperature increase of up to 200 K resulting from the multi-stage compression of the gas is used to bring a water-cooling circuit to the highest possible temperature level, while at the same time ensuring that the gas is kept at a maximum outlet temperature of 40 °C for the customer process. This provides further added value, as the gas is also made available to the downstream dryer at an optimum inlet temperature for drying. http://hydrogen.jumo.info You‘re on the safe side with JUMO JUMO offers sensor and automation solutions for such devices as electrolyzers, fuel cells, storage tanks, and synthesis plants. In doing so we support the production of green hydrogen and its use in the various application areas. As a result, we move the energy transition forward and develop solutions for the future.
