Constant power production with an organic Rankine cycle from a fluctuating waste heat source by using thermal storage K. Couvreur 1 , J. Timmerman 1 , W. Beyne 2 , S. Gusev 1 , M. De Paepe 2 , W.D. Steinmann 3 , and B. Vanslambrouck 1* 1 Department of Flow, Heat and Combustion Mechanics, Ghent University – UGent, Graaf Karel de Goedelaan 5, 8500 Kortrijk, Belgium 2 Department of Flow, Heat and Combustion Mechanics, Ghent University – UGent, Sint-Pietersnieuwstraat 41, 9000 Gent, Belgium 3 Institute of Technical Thermodynamics, German Aerospace Center (DLR), Pfaffenwaldring 38-40, 70569 Stuttgart, Germany * Corresponding author: Bruno.Vanslambrouck@Ugent.be Abstract In energy intensive industries, organic Rankine cycle (ORC) systems can significantly increase energy efficiency and reduce carbon emissions by converting low- and medium- temperature waste heat to electricity. However, fluctuations in waste heat availability can negatively affect the operation of an ORC unit. By integrating intermediate thermal energy storage these fluctuations can be mitigated and part-load operation of the ORC unit can be avoided. This paper describes the design of a test rig to investigate combined LHS ORC systems and the set-up of future experiments. The test rig consists of a 110 kWh latent heat storage (LHS) system, connected to a 250 kWe heater and a 11 kWe ORC unit. For optimal integration and operation of LHS systems, effective operating strategies and methods to monitor the state of charge (SOC) need to be composed. Keywords: waste heat recovery, organic Rankine cycle, thermal energy storage, latent heat storage. Introduction In 2013, 25% of the total energy consumption of the European Union could be allocated to the industry sector. In 2014, 20% of the greenhouse emissions originated from manufacturing processes [1]. A considerable amount of the industrial primary energy (20 – 50%) is lost in forms of low grade waste heat in large scale thermal systems [2]. However, by exchanging this waste heat between thermal processes or converting it to electricity, fossil fuel consumption and related emissions can be decreased. The recovered energy can be either reused directly in the same industrial site where it is produced, or it can be fed in a distribution network. Waste heat to power (WHP) systems such as ORC create opportunities to increase the energy efficiency in energy intensive industries and reduce emissions [3]. Typically, in WHP applications, two phase power cycles are frequently used to recuperate waste heat. Waste heat is recuperated and transferred to a working fluid of which the properties are adapted to the waste heat source temperature. Subsequently mechanical energy is generated in an expander coupled to an electric generator. Common and well developed power cycles include steam Rankine cycle, ORC and Kalina cycle. The ORC is considered as a viable technology for converting low- and medium-temperature heat to electricity for which it is difficult to apply the normal steam Rankine cycle [4, 5]. The working fluid is an organic fluid with a low boiling temperature, lower latent heat and a small specific volume compared brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Ghent University Academic Bibliography