oemof Workshop on Modeling Heat Pumps

oemof Workshop on Modeling Heat Pumps#

Welcome to the documentation of the oemof session at the 2nd International workshop on “Open Source Modelling and Simulation of Energy Systems”. The workshop has been developed by Francesco Witte and Patrik Schönfeld at the German Aerospace Center (DLR), Institute of Networked Energy Systems.

You will learn how to use and apply the two most know oemof libraries, i.e. oemof.solph [1] and TESPy [2], in the context of modeling heat pumps in energy system analysis. If you would like to add more contents you are welcome to open a pull request on the repository.

Abstract#

Since the implementation and operation of heat pumps is considered one of the major key-elements for the decarbonization of the heat sector. Modelling these for energy system analysis, which usually applies linear or mixed integer programming, has thus become a well-known task in various temporal and spatial model scopes. Even in a linear program the model can integrate a varying COP as function of ambient and heating temperature curves by pre-calculating the Carnot COP and assuming an efficiency factor. To account for more detail in the model, for example minimum part load or part load variable COP, a mixed integer formulation is required. However, this implementation also requires more technical information on the heat pumps performance at varying conditions. Such data can be retrieved from literature sources or databases, e.g. hp_lib [3] which provides a good overview on general performance parameters for heat pump models of many manufacturers. However, using these sources falls short in case the part load performance or temperature ranges should be assessed, which are out of the industry standard scope, for example in novel research applications. A dedicated thermodynamic simulation model can fill this gap.

Structure of the Tutorial and Teaching Method#

In this tutorial researchers and modelers will therefore learn to

  • model heat pumps in linear and mixed integer linear programs,

  • calculate the heat pump’s performance in a dedicated thermodynamic model, and

  • how to combine these methods in order to improve the representation of a heat pump in the energy system model.

The software applied in the tutorial session will be oemof-solph as energy system optimization tool and TESPy as thermodynamic modelling framework. Both are part of the popular open energy modelling framework oemof.

Conceptually, the tutorial is divided in three learning steps:

  • To pick up the participants, a broadly known approach on modelling heat pumps with respective pre-calculation of the Carnot COP and assumption of a constant efficiency factor is applied in oemof.solph in the first step.

  • Second, a simple thermodynamic model of the 4-component heat pump is built using TESPy and the respective parameters required in the first step of the tutorial are calculated and then transferred to the oemof.solph model.

  • The two known approaches are then combined and extended in the third step: The TESPy model will be modified to enable calculation of the COP in part load operation within the full range of heat source and heat sink temperature values. The oemof.solph model will employ a piece-wise linear approach to model different efficiency values at different part load operation ranges. Finally, the information from the non-linear thermodynamic model are linearized and transferred to the oemof.solph model.

Preconditions for Participants#

It is recommended, that participants have basic knowledge on modelling linear and mixed integer problems as well as using Python. Furthermore, an understanding of a heat pump’s components and its physical properties are useful. While not required, it is possible to self-prepare specifically for the frameworks used in this tutorial with numerous examples available on the respective documentation websites.

Acknowledgements#

We would like to give a special Thank You to the awesome oemof community, which - independently of institutions - has been able to put out some amazing libraries for energy modelers word wide.

This work was funded by the German Federal Ministry of Education and Research (BMBF) in the project Wärmewende Nordwest (grant number 03SF0624L).

LICENSE#

MIT License

Copyright (c) 2023 Francesco Witte, Patrik Schönfeldt

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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