Evaluation of optimisation potentials of a solarassisted DEC-system at the town hall of Gleisdorf

The latest technology-roadmap for solar cooling reports that 21 solar thermal cooling systems are documented in Austria, whereof only 3 are desiccant evaporative cooling systems (DEC-systems). Due to this low number of solar cooling systems, the gained experience with the operation and system design is still limited. The goal of this work is to develop a validated model of a DEC-system as well as to analyse optimization measures to gain know-how for future systems. As basis for the modelling, the DEC-system at the town hall Gleisdorf was used. As simulation environment, TRNSYS 17 was chosen, because of the experience with this software and the available libraries, which provide a good basis for modelling a DECsystem. For the development of the simulation model, the system was divided into 3 subsystems, which were validated with monitoring data individually (subsystems: solar system, storage, DEC-system). The modelling of the storage has demonstrated that the model is of limited use for long time simulations, due to software problems. Therefore, this model could not be used for the simulation of the entire system. For the other subsystem, a sufficient accurate model has been developed. Subsequently, 3 optimization measures were determined. Based on these measures, 4 variants have been simulated and the impacts on the supply air temperature along with the regeneration temperature have been analysed. The simulations have shown that even the applied modifications cannot ensure that the set point temperature for the supply air is reached at any time. The measures reduce the duration of temperature violations by around 21 %. However, the set point cannot be reached in 16 % of the time. Regarding the regeneration temperature, the simulations have confirmed that the temperature is too low to ensure a full regeneration of the sorption wheel. However, by implementing a change of the hydraulic connection or a larger heating coil, an increase of the temperature can be realised. Thus, it is possible to counteract the odour without significant changes for the system.