Abstract
For the implementation of existing optimisation potentials in industry, commerce and district heating, it is important to expedite the reduction of waste energy and consequently of the primary energy demand as well as CO2 emissions and additionally to integrate renewable energy technologies. To reach these goals, complex optimisation principles are needed, due to the fact that heat and cold demand and availability vary in time and need to be aligned also including continuous as well as batch processes which can be found in all industry. For this reason heat and cold storages are indispensable and necessary for increasing the resource and energy efficiencies in complex energy systems.
It has been proven that the pinch analysis is a very suitable method for the design of an optimised overall energy system. This has been shown for renewable energy integration at total sites (Varbanov and Klemeš, 2010) and specifically for solar thermal integration (Brunner et al., 2008). Recently the approach has been applied for energy efficiency and renewable energy integration in breweries (Muster-Slawitsch et al., 2011). Several authors worked with algorithms including batch processes and storages in the pinch analysis but until now no software tools for the purpose of designing complex storage systems under practical considerations are available. To close this gap, the tool SOCO (Storage Optimisation Concepts) has been developed that is able to plan and design complex storage systems on the basis of real life process data coming from the industries, commerce and district heating businesses (Fluch et al., 2012). The application enhances possibilities of demand reduction (heat integration), increases the measures on energy efficiency and boosts the implementation of economically and technically reasonable renewable energy technologies (focus on solar process heat). Included in SOCO is a Pinch Analysis on the basis of real life data with varying heat load profiles and the possibility to create heat exchanger networks. Based on the illustration of the residual load profile with its different temperature levels the best possible way of integrating renewable energy technology can be shown. Furthermore, one of its main topics is the design of storage systems with regards on the heat exchanger network, previously calculated within the pinch analysis, and with regards on the possibility to implement renewable energies. Therefore, the storage itself is simulated using a node model adapted for storages with a fixed level and a varying level. Based on these simulations SOCO optimises the amount, style, dimension and design of the storage systems as type of storage, insulation, connections, charging and discharging of the storages.
Within the project data of 10 storage systems have been evaluated and out of these three detailed case studies have been performed (two integrated in a production process, one storage system of a district heating network). It can be stated that based on the evaluation of the status quo significant optimisation can be reached by an optimised combination of processes with heating and cooling demand, an optimised storage management including the control systems and the charging and discharging strategies and an optimised design of the storage itself. The thereby achievable increase of efficiency of the storage and respectively the increase of the total energy efficiency in the production process is up to 20 %.
It can be stated that the developed SOCO tool is a very useful software and methodology for the optimisation of energy efficiency in industry, commerce and district heating. The user is able to design the status quo and based on real data the developed algorithms for heat integration including the storage system and management suggest an optimised solution with the target of energy efficiency and integration of renewable energy sources.
