Low order thermal network models for dynamic simulations of buildings on city district scale

• A low order thermal network model based on the VDI 6007-1 has been implemented.
• Preprocessing tools for parameterization simplify the model handling.
• The implementation has been verified on test cases given in the VDI 6007-1.
• A comparison to the widely used ISO 13790 showed good results.
• The simulation of a city district use case achieved good compliance.

Dynamic building models can be a valuable part of integral energy system models at city district or urban scale, if parameterization and computation times do not exceed a practical limit. Low order thermal network models are able to represent a thermal zone by thermal resistances and capacitances with low computational costs. Yet, the widely used first-order model of ISO 13790 is only validated for a monthly time step. Following a similar approach, the Guideline VDI 6007 proposes a second-order model explicitly for transient simulations. Thus, the aim of this paper is to show how a building model based on this guideline performs in dynamic building performance simulations, compare its results to those of the ISO 13790 model, and evaluate its suitability for city district simulation.To this end, we implemented both building models from Guideline VDI 6007 and ISO 13790 in Modelica. We verified the VDI-model by simulating 12 test cases given in the guideline. To compare both models we defined a test case which evaluates the influence of outdoor air temperature on indoor air conditions. The VDI-model was subsequently used to simulate the buildings of a research campus as a performance test on city district scale. We parameterized the campus using building archetypes depending on four basic values.In all tests, the VDI-model proved to be a suitable solution for city district applications. Even so, defining suitable boundary conditions is of high importance and uncertain parameters like the periodic depth of penetration are subject to further investigations.