Computer modelling

Computer modelling

As well as developing and supporting the School, thermal model HTB2, computer modelling facilities are offered in the areas of CFD (Fluent and inhouse codes), Lighting (Radiance, Superlite), Regional energy and pollution (EEP), and computer based design aid tools.

Environmental Design Software

The school has developed a number of computer based design aid tools for use by our students. These have no warranty and limited support.

Thermal Comfort Meter Version 1.1

Thermal Comfort Meter allows the complex thermal comfort model, as proposed by P.O.Fanger and as adopted for ISO 7730, to be explored.

The interaction between the user and the calculations through the screen display allow the student to observe the interaction of environmental conditions and occupant comfort. The meter may be used to investigate the Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD) parameters for prescribed environmental conditions, or alternatively it may used to seek appropriate conditions for a target comfort criterion.

Two interfaces are available, the simple form provides a constrained choice of parameters, while the advanced form allows full access to all the parameters of the model. The help system provides a full explanation of each function and parameter. This runs under Windows 9x,NT and 2000.

HTB2: Thermal Simulation of Buildings

HTB2 is a software suite intended for the general purpose simulation of the energy and environmental performance of buildings. It is suitable for use within research, teaching and design environments. Based on a simple Finite Difference Heat transport model, it incorporates sub-models for;

  • fabric heat transport and thermal storage
  • internal and external thermal radiation exchange
  • the transfer of heat and moisture by ventilation and infiltration
  • heating and cooling plant and controls characteristics
  • incidental internal heat sources
  • occupant control and intervention.

Computer Modelling

  • Room air and radiant temperatures
  • comfort parameters
  • fabric temperatures
  • humidity levels
  • heating system use
  • ventilation rates
  • zone to zone energy flows

can all be determined from a simulation. Informed decisions based on the evaluation of the impact of design options on such performance indicators can be made.

Energy and Environmental Prediction (EEP)

The Energy and Environmental Prediction model (EEP) is a computer based modelling framework that quantifies energy use and associated emissions for cities to help plan to reduce carbon dioxide (CO2) and other emissions. EEP has been developed at Cardiff University since October 1994 with funding from the UK Engineering and Physical Sciences Research Council (EPSRC).

Model Structure

The EEP model is based on Geographic Information System (GIS) techniques and incorporates a number of sub-models to establish current energy use and CO2 emissions produced by domestic and non-domestic buildings, traffic and industrial processes for a city or region. Each sub-model uses UK Government accepted procedures to predict energy use and emissions with the exception of the traffic sub-model that has been developed using Spatial Analysis procedures. The model can predict the effects of future planning decisions from a whole city level down to a local level. The user can identify 'hotspots' of energy use and emissions that can be targeted to make environmental improvements. Each sub-model is linked through the GIS framework and can be accessed from a main menu screen. The EEP model uses an integrated approach that allows simultaneous appraisal of energy and pollution from one or a combination of built environment sectors. EEP is flexible enabling current sub-models to be updated as more accurate procedures are developed and as further sub-models are required.

Data Collection

Data for the model is collected from a variety of sources including maps, historical records and 'drive by' surveys. The EEP model acts as a database to store property based information that is collected. In order to plan and predict energy use to a high degree of accuracy a large amount of information is required. A 'rapid' data collection survey method has been developed to collect information to a satisfactory level unobtrusively, and within the time and staff resources available within local authorities budgets.

Data Presentation

The EEP model presents results in the form of thematic maps that highlight pollution or energy hotspots throughout a region. Results are presented to postcode level. These can be used to pinpoint areas of high energy use that can be targeted for improvement.

Application of the Model

The EEP model has been designed to be transferable to other cities worldwide. The model is directly transferable to UK cities. It was initially developed in Cardiff (Wales) and has been applied to Camden (England), Leicester (England), Belfast (Northern Ireland), Neath Port Talbot County Borough Council (Wales) and Newcastle (Australia). Neath Port Talbot County Borough Council is the first local authority area where the EEP model is being applied fully, this has led to further work to promote energy efficiency to owner occupiers.