Digital Twin for Heat Pump Systems

Description of a holistic approach consisting of numerical models and system platform

Abstract

Numerical building simulation is a tool that has been used intensively for years to analyse systems engineering in buildings. In the past, the focus of the development work was increasingly on the creation of detailed partial models and the coupling to other simulation programs, which was called co-simulation in the professional world. The development work regarding the coupling of building and plant simulation programs with programs of the numerical flow simulation is to be mentioned here. Currently, the coupling to measurement technology is pushed more strongly, whereby the focus is seen on the parallel use of the numerical model to a real system. This development is called "digital twin" of components or subsystems in power engineering. The following article addresses this development and would like to describe the system concept of a digital twin using the example of a heat pump technology. Based on the characterization of a special use case, the digital twin will first be divided into the development phase, field test phase, and deployment phase of heat pumps. Different model accuracies of the digital twin are assigned to the individual phases. In a second step, the different models for the component’s compressor, heat exchanger, expansion valve, and the necessary piping are described. The coupling to a building simulation program is also part of the article. Furthermore, an essential point is the interaction with a cloud platform, in which the comparison between measured values and values from the digital twin takes place. Here, the focus is on the data exchange formats and the additional analysis tools that were used in the system concept. The paper concludes with a demonstration of an example under laboratory conditions within the Combined Energy Lab (CEL) of the TU Dresden.