jm-eb-nd-cibse-ts-2016-v03.pdf (910.92 kB)

Real-world validation of climate-based daylight metrics: mission impossible?

Download (910.92 kB)
conference contribution
posted on 04.05.2016, 12:50 by John Mardaljevic, Eleonora Brembilla, Nafsika Drosou
One of the criticisms of metrics founded on climate-based daylight modelling (CBDM) is that they are unverifiable in practice. This criticism received some attention following the decision in 2013 by the Education Funding Agency to make CBDM and the useful daylight illuminance (UDI) metric a mandatory requirement for the evaluation of designs submitted for the Priority Schools Building Programme. Some of the difficulties related to the validation of CBDM metrics apply also to daylight factors. However, several other challenges need to be addressed and practical solutions found before any attempt at validation of CBDM metrics can be made. This paper identifies those challenges and describes a framework for the practical evaluation of daylighting performance in real world settings, and thus a basis for the validation of CBDM metrics. The task of validation requires a conflation of state-of-the-art techniques in measurement and modelling. Measurement techniques under consideration include high dynamic range imaging and ‘smart sensors’. A key obstacle to real world validation in, say, classrooms is that it is often not possible to rely on measurements of illuminance taken on the horizontal plane because such locations are rarely free from disturbance during normal use. It becomes necessary therefore to measure illuminance at more reliable locations (e.g. walls) and use these as a proxy for illuminance performance on the horizontal. The relation between wall and desk performance is space-specific and can be determined using CBDM. The first steps towards practical application of this framework are described.

Funding

Ms. Brembilla acknowledges the support of the EPSRC and industrial partner Arup (London, UK), and Ms. Drosou the support of the EPSRC LoLo Doctoral Training Centre in Energy Demand.

History

School

  • Architecture, Building and Civil Engineering

Published in

CIBSE Technical Symposium

Citation

MARDALJEVIC, J., BREMBILLA, E. and DROSOU, N., 2016. Real-world validation of climate-based daylight metrics: mission impossible? Presented at: CIBSE Technical Symposium 2016, 14th-15th April 2016, Heriot-Watt University, Edinburgh.

Publisher

Chartered Institute of Building Services Engineers (CIBSE)

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Acceptance date

14/04/2016

Publication date

2016

Notes

This is a conference paper.

Publisher version

Language

en

Location

Edinburgh

Exports

Logo branding

Exports