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Mechanical Engineering Commons

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Technological University Dublin

Finite-difference

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Full-Text Articles in Mechanical Engineering

International Energy Agency Bestest For Ground Coupled Heat Transfer, Joel Neymark, Ron Judkoff, Michael Crowley Sep 2008

International Energy Agency Bestest For Ground Coupled Heat Transfer, Joel Neymark, Ron Judkoff, Michael Crowley

Reports

The objective of this project is to assess the accuracy of building energy analysis tools that have incorporated detailed models for predicting ground-coupled heat transfer related to floor slab and basement constructions. An executive summary is to be found in the main report.


Improved Direct Solver For Building Energy Simulation, Michael Crowley, Saleem Hashmi Jan 2000

Improved Direct Solver For Building Energy Simulation, Michael Crowley, Saleem Hashmi

Articles

Finite difference methods, when applied to the differential equations modelling energy flows in buildings, give rise to a system of non-linear difference equations. A frequently used direct solution method involving linearization is analysed and a related method proposed. These and one other connected method are compared using a building related test problem prepared for this purpose. The proposed numerical method is found to produce least error, about 30% less than the commonly used method, and it is recommended for inclusion in building energy simulation software. A fundamental method for estimating the pre conditioning period of a building, arising from the …


Evaluation Of Implicit Numerical Methods For Building Energy Simulation, Michael Crowley, Saleem Hashmi Jan 1998

Evaluation Of Implicit Numerical Methods For Building Energy Simulation, Michael Crowley, Saleem Hashmi

Articles

The stability of numerical methods used for finite-difference thermal modelling of buildings is discussed. A known instability in a commonly used process is described and alternative numerical methods with suitable stability properties are identified. With a view to selecting the optimum numerical method, the building energy simulation problem is characterized mathematically and appropriate implicit solvers are compared on the basis of accuracy and computational effort using a building related test problem prepared for this purpose. A recently developed numerical method with the necessary strong stability is found to possess higher computational efficiency than methods frequently used in this application and …