Lumped-element model: Difference between revisions

Revision as of 11:49, 29 March 2016

Revision as of 02:18, 9 April 2016

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The simplifying assumption in this ___domain are:

* all heat transfer mechanisms are linear, implying that radiation and convection are linearised for each problem;

Using Lumped Element Models (LEMs) to represent the building thermo-dynamics does not offer the same accuracy than more complex numerical methodologies such as EnergyPlus and IES <VE>; however, it allows to perform dynamic simulation of buildings with reduced computational cost. The simulation suite CitySim by Darren Robinson uses LEMs, what reduce greatly the computational times of performing the simulations. This allows to perform stochastic analysis and urban simulation.

Several publications can be found that describe how to generate LEMs of buildings. In most cases, the building is considered a single thermal zone and in this case, turning multi-layered walls into Lumped Elements can be one of the most complicated tasks in the creation of the model. Ramallo-González's method (Dominant Layer Method) is the most accurate and simple so far.<ref>Ramallo-González, A.P., Eames, M.E. & Coley, D.A., 2013. Lumped Parameter Models for Building Thermal Modelling: An Analytic approach to simplifying complex multi-layered constructions. Energy and Buildings, 60, pp.174-184.</ref> In this method, one of the layers is selected as the dominant layer in the whole construction, this layer is chosen considering the most relevant frequencies of the problem. In his thesis,<ref>Ramallo-González, A.P. 2013. Modelling Simulation and Optimisation of Low-energy Buildings. PhD. University of Exeter.</ref> Ramallo-González shows the whole process of obtaining the LEM of a complete building.