Bachelor's thesis Steffen Brill

 

Analysis of the dynamic behaviour of micro-scaled combined heat and power units and heat pumps

The production of electricity based on renewable energies will steadily grow in the future. This will cause increasing fluctuations in the electricity grid on the local level, which needs to be balanced. Hence new concepts will be developed. One interesting opportunity is a clever demand side management of grid-connected heating devices. Therefore, heating devices, which produce heat by also producing electrical power or by consuming electrical power will operate net driven on the basis of a residual electrical load profile.

In this work, the dynamic behaviour of different grid-connected heating devices is analysed. The capability of the systems to operate in part-load, as well as the transient response characteristics are examined. Also, the start-up and shut-down characteristics are considered. Special attention is paid to minimum time durations, which the heating devices have to run after it was turned on and has to rest after it was turned off.

With those aspects, a dynamic model is created, which is intended to be used in whole-building simulation programs. To identify the impacts of the consideration of those dynamic aspects, some simulations are accomplished and the results are compared with simulation results of existing models. Furthermore, the impacts of a changed operation strategy and the share of photovoltaics are analysed.

It is shown, which dynamic aspects have a significant influence on yearly whole-building simulations, whether it is useful to implement the dynamic aspects in the models at all and if the simulation time interval needs to be changed. In the future models, which account the dynamic behaviour of, the in this work considered, gridconnected heating devices can be used for whole-building simulations.