High temperature heat pumps in Austria: Demonstration and application examples

Austrian industry consumed 385 PJ of final energy in 2016 [1]. Approximately 25% thereof were covered by natural gas. It was used for industrial applications that are relevant for heat pumps, such as space heating and air conditioning, steam generation and industrial ovens. Space heating and air conditioning are typical fields of applications for heat pumps. Industrial ovens comprise all kinds of ovens ranging from low-temperature applications, such as drying to high-temperature processes, such as sintering. Steam generation also covers a broad range of temperatures. Both applications are therefore partially relevant for heat pumps. The integration of heat pumps into industrial processes is still in a rather early diffusion phase in Austria despite the large technical potential according to the national technology and implementation roadmap for heat pumps. This roadmap was developed in a comprehensive participatory stakeholder process and was published in 2016. It is based on the strengths of the Austrian heat pump sector and the users´ needs. Industrial processes were identified as one of four main fields of applications for heat pumps. The recommendations for research and development institutions comprise the implementation of model solutions and pilot systems, heat pumps for higher supply temperatures and new concepts to enable widest possible market penetration. [2] Three application examples of high temperature heat pumps are presented, covering the food industry, metal industry and utilities. All examples are brown-field installations, where the heat pumps were integrated into existing processes to recover waste heat from different sources, such as flue gas condensation, chillers and cooling water. In these examples, the heat provided by the heat pumps is fed into district heating grids. The supply temperatures range from 78 - 95°C, the heating capacities from 4 - 40 MW. These heat pumps were commissioned in the last four years, also reflecting the increasing spread of industrial heat pumps in Austria. European legislation aiming at an increase in renewables in electricity supply and reduction of CO2 emissions, as well as further development of the technology according to the needs of industrial applications are important drivers to spread heat pumps in industry. Current research activities focus on high temperature heat pumps, new refrigerants and efficiency measures, as well as holistic planning approaches for industrial sites. Among other projects, DryFiciency, an H2020 project, is presented in more detail. Two heat pump demonstrators are developed, constructed and operated in a real industrial environment. They are closed loop compression heat pumps operated on OpteonMZ supplying up to 400 kW heat at 160°C. The heat pumps are integrated in industrial drying process in two Austrian companies, Agrana Stärke GmbH (starch drying) and Wienerberger AG (brick drying). The heat pumps are currently about to be commissioned. Then, extensive monitoring of the operation will start to evaluate efficiency and other important process parameters, as well as stability of refrigerant and lubricant when exposed to high temperatures. There is increasing demand for industrial heat pumps in Austria, as they allow for waste heat recovery, efficiency increase and electrification and will therefore play a major role in the future energy system. With heat pumps that deliver high temperature heat up to 160°C, a larger range of applications in industry can be covered. To satisfy the needs of industry, high availability and short payback periods are required. It is therefore essential to come up with reliable and cost-efficient solutions for the technological challenges for high temperature heat applications, such as temperature resistant materials and components. Successful demonstration projects are an important basis to establish trust in new technologies and for further roll out.