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Technological University Dublin

Series

2000

Stiff systems

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Full-Text Articles in Engineering

Development Of Exponential-Fitted Numerical Methods For Building Energy Simulation, Michael Crowley, Saleem Hashmi Jan 2000

Development Of Exponential-Fitted Numerical Methods For Building Energy Simulation, Michael Crowley, Saleem Hashmi

Conference papers

Simulation of energy flows in buildings is computationally intensive. Consequently, improvements in computing power and algorithm efficiency can always be utilized. Commonly used implicit solvers require extensive matrix processing while standard explicit methods have limited stability and progress in very small time increments. In this work, a number of stable numerical methods are examined which are explicit in nature and therefore do not require the use of matrices. One such algorithm and two proposed developments of it are assessed using a building related test problem prepared for this purpose, and their performances are compared with that of an efficient implicit …


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 …