Ground Storage Heat Transfer with Non-Linear Features Modeled in the Frequency Domain
2008 (English)Conference paper (Other academic)
The strategy chosen in the present work is to use standard finite element software which gives the possibility touse triangular elements and to run different physical models in parallel and with interaction between the models.This creates possibilities of rational solution of large thermal field problems. The modern finite elementsoftware gives the user the possibility to create macros or scripts for administration of calculations giving thepossibility within the software environment to convert real time data into Fourier series, run the solution for alarge set of frequencies and to carry out the inverse transformation of the results to time series. By separation ofthe ground heat flow and the duct heat balance a technique for the introduction of variable air flow is developed.The use of the technique is demonstrated for annual ground heat storage in a duct under a building. As shown bythe examples in the paper the new tools for finite element modeling of different processes opens up a new fieldof opportunities in the treatment of problems within building physics. An advantage is that the solution forvarious processes can be interlinked and the high level script formalism gives the possibility to implement thefield problems in the treatment of whole systems in a rational way. In the paper it is shown how the frequencydomain solution for heat transfer can be implemented into existing finite element software and how the solutioncan be combined with constant mass flow in pipes and ducts. It is furthermore outlined and demonstrated howthe treatment of variable mass flow can be carried out in reasonable time utilizing advanced iterative solutions.
Place, publisher, year, edition, pages
2008. 79-86 p.
Buildings, ground heat storage, finite element, modelling, frequency domain, variable mass flow
IdentifiersURN: urn:nbn:se:kth:diva-80769OAI: oai:DiVA.org:kth-80769DiVA: diva2:496710
8th Symposium on Building Physics in the Nordic Countries. Copenhagen, Denmark. June 16-18 2008
QC 201205142012-02-102012-02-102012-05-14Bibliographically approved