BRE asset rating tool

A recent BRE research project to develop a prototype energy certification tool / asset rating calculator for non-domestic buildings has come into fruition. The work follows on from an earlier scoping study to determine the technical and user requirements and feasibility of developing such a tool to meet specifications in the EU Directive on the Energy Performance of Buildings.

Earlier work concluded that it would be possible, and desirable, to develop a building energy calculation tool based on dynamic simulation. As a result, the aim was to produce a demonstration version to show how it might operate in practice. The original intention at the start of the project was to generate a model that would provide an effective data entry interface for existing buildings. This would allow thermal and building service performance characteristics to be inferred from observable building features (e.g. the u-value of a wall from the building age, construction materials and wall construction type).

Since the project began, however, significant advances have been made to the calculation procedures based on the Design Builder software using Energyplus as the calculation engine. Whilst this tool provides the functionality required to calculate an energy performance rating, it is essentially a research tool and as such, the data input screens appear complex. Consequently, work on the demonstrator centred around developing a user friendly interface and on gathering information needed for the inference routines.

The BRE approach illustrates how (with recourse to inference procedures) the data input needed to calculate an energy rating can be minimized, whether based on dynamic simulation or a simplified method. The focus was very much on the minimum amount of information needed and the way this could be collected; how it might look in practice. Since, the difficulty lies in ascertaining what individual wall structures are like, the tool works by asking users what they DO know. The tool also demonstrates how this might be achieved by inviting the user to chose from a selection of pictures that are the best match for their building.

A data interface has been developed as a web based 'click thorough', which effectively demonstrates the likely data input requirements for generating energy performance ratings. The interface gives the look and feel of an on-line energy calculation assessment but is not connected to energy calculation engine. It does, nevertheless, give an idea on what such a tool might be like. It also generates a mock certificate that presents information in a way that could be audited. It is in effect, the management side of how certification could look.

The demonstrator can be accessed at www.solsticetrial.com/bestcert.