jm-eb-nd-cibse-ts-2016-v03.pdf (910.92 kB)
Real-world validation of climate-based daylight metrics: mission impossible?
conference contribution
posted on 2016-05-04, 12:50 authored by John MardaljevicJohn Mardaljevic, Eleonora Brembilla, Nafsika DrosouOne 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 SymposiumCitation
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
2016-04-14Publication date
2016Notes
This is a conference paper.Publisher version
Language
- en