the influence of thermochromic glazing parameters on ... · climate conditions • tc glazing...
TRANSCRIPT
2
The Influence Of Thermochromic Glazing Parameters On Energy Saving And Comfort
Criteria Using Moment-independent Measure
Arthur Ah-Nieme
PhD candidate, M.Sc.Eng in Building SciencePIMENT Laboratory /University of La Réunion
3 Context
Global Warming
Building sector
Building envelope
performance (Pérez-Lombard and al.,
2008)
Transparent
surfaces (Bülow-Hübe, 2001)
4 Context
Windows is important to provide:
• An exterior view
• Daylight
Windows play an essential role in Architecture (Carmody et al., 2004)
And also to:
• Thermal and phonic insulation
• Solar control
• Air quality control
• Security
5
Vanadium Dioxide: 𝑉𝑂2• Thermochromic properties
(Morin, 1959)
• Transition temperature : 68°C (Granqvist, 2016)
• Doping with other metals :➢ In Li and al., 2012 :
• Increase of the visible transmittance
• Increase of the solar modulation
➢ In Dietrich and al., 2015 : • Decrease of the transition
temperature
Thermochromic Glazing (TC)Has the capability to modulate its thermo-optical properties dynamically and
reversibly when a change in its temperature occurs
Literature review
• In Saeli and al., 2010 : (Cairo, Palermo, Roma)▪ ~30-40 % of energy savings in comparison to a
simple clear glazing
• In Liang and al., 2015 : (London, Guangzhou)▪ Diminution of the cooling need
▪ ~10-15 % of energy savings in comparison to a double glazing
▪ Decrease of glare occurrence
• In Costanzo and al., 2016 : (Catania, Milan, Paris)▪ ~10% of discomfort time (Top>26°C) in
comparison to a double glazing
▪ ~25% of energy savings (max for hottest climate)
▪ Decrease of glare occurrence and improvement of illuminance distribution
6
• TC glazing for building application:
• Has to be doped with other metals to improve its properties• Transition temperature
• Visible Transmittance
• Solar modulation
• Has a potential to (Hoffmann et al., 2014)
• Reduce energy consumption
• Improve thermal and visual comfort
• Has a real efficiency for hot climates
Thermochromic Glazing (TC)
Literature review
7 Aim of the study
Identify the influence of thermochromic glazing parameters for hot climates using dynamic building simulations and sensitivity analysis techniques
❖ Thermal and daylighting simulations with EnergyPlus (DOE, 2010)
❖ Sensitivity analysis method with a Python code with the SAlib (Usher et al., 2016)
❖ Analysis on several indexes
❖ Study on 4 locations (hot tropical climates)
Saint-Denis
Chennai
Weipa
Townsville
Tropical savanna climate (Kottek and al., 2006)
8 Methodology
Hypothesis: (office building)▪ Dimensions: 6m x 5m x 3m▪ Glazed surface exposed to solar radiation and wind▪ Other surfaces are adiabatic▪ No exterior obstructions
▪ Occupation: (Hoffmann et al., 2014)
▪ 8am to 5pm
▪ activity: 240 W (2 people)
▪ Electric equipment loads: 150 W/person
▪ Artificial lighting: 8 W/m²
▪ If 𝐸𝑟𝑒𝑓𝑠 < 300 lux (CIE, 2002)
▪ Air conditioning :▪ 𝑇𝑠𝑒𝑡 = 24°𝐶
▪ Flow rate: 20 Τ𝑚3 ℎ per person
Simulations performed over an entire year
9 MethodologyThermochromic glazing model in EnergyPlus (DOE, 2010)
𝜏
T (° C)
𝜏𝑚𝑎𝑥
𝜏𝑚𝑖𝑛
∆𝜏
Ts
Δ𝑇𝑠
Initialize 𝑇𝑇𝐶𝑡
Find 𝜏𝑡+1
Solve heat balance and photometric model
𝑇𝑇𝐶𝑡+1
Number of states = 5
10 Sensitivity analysis
INPUT VARIABLES SYMBOL RANGE UNIT PROBABILITY
Building Orientation BO 0-360 ° Continuous; Uniform
Window to Wall Ratio WWR 5-99 % Continuous; Uniform
Insulation Thickness 𝜃𝑖𝑛𝑠 0.01-0.7 m Continuous; Uniform
Weather File wea 1-4 - Discrete; Uniform
Switching Temperature 𝑇𝑠 5-70 °C Continuous; Uniform
Switching Temperature range ∆𝑇𝑠 1-50 °C Continuous; Uniform
Solar Transmittance Max 𝜏𝑠𝑜𝑙,𝑚𝑎𝑥 0.3-0.9 - Continuous; Uniform
Solar Transmittance range ∆𝜏𝑠𝑜𝑙 0.01-0.5 - Continuous; Uniform
Visible Transmittance Max 𝜏𝑣𝑖𝑠,𝑚𝑎𝑥 0.3-0.9 - Continuous; Uniform
Visible Transmittance range ∆𝜏𝑣𝑖𝑠 0.01-0.5 - Continuous; Uniform
Number of states state 2-20 - Discrete; Uniform
Moment-independent measure (Borgonovo, 2007)
𝛿𝑖 =1
2𝑬𝑋𝑖 න 𝑓𝑌 𝑦 − 𝑓𝑌|𝑋𝑖 𝑦
Distribution and sampling of the parameters
Simulation of each parameters set
𝐼
Analysis of Delta on the output
4096 simulations
11
Energy consumption index
• Sum of the final energy consumed in one year
• Cooling and artificial lighting
Normalized output indexes
Model Outputs
Thermal comfort index (Costanzo and al., 2016)
• % of time when the temperature is below 26°𝐶
Visual comfort index (David and al., 2011)
• % of time when the illuminance reference points are between 300 and 2000 lux
12 Results
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Insulation thickness
Switching temperature range
Visible transmittance range
Number of states
Visible transmittance max
Switching temperature
Solar transmittance range
Weather File
Solar transmittance max
Orientation
Window-to-Wall Ratio
delta
Iec
Ith
Iv
τ
T (°C)
𝜏𝑚𝑎𝑥
𝜏𝑚𝑖𝑛
∆𝜏
Δ𝑇𝑠
Ts
Energy index
Thermal index
Visual index
Delta Moment measure analysis
13
• Filtering model outputs according to a criteria
• Sorting given inputs by glazing size (small, medium, large)
Distribution of input parameters
Results
Output distribution Input distribution after filtering
14
Energy consumption: [0; 0.40]
Distribution of input parameters
Results
WWR[5% - 35%[
WWR[35% - 65%[
WWR[65% - 99%]
𝑇𝑠 [°C]𝜏𝑠𝑜𝑙,𝑚𝑎𝑥 Δ𝜏𝑠𝑜𝑙
Fre
quency
15
Visual comfort : [0.70; 1]
Distribution of input parameters
Results
WWR[5% - 35%[
WWR[35% - 65%[
WWR[65% - 99%]
𝑇𝑠 [°C]𝜏𝑣𝑖𝑠,𝑚𝑎𝑥 Δ𝜏𝑣𝑖𝑠
Fre
quency
16 Limitations and drawbacks
• The TC glazing model used in EnergyPlus
▪ Step function : not representative of the real thermal behaviour (Mlyuka and al., 2009)
• The geometry and building configuration
• The input uniform probability
17 Conclusion
• Impact of several input variables on several model outputs
• Designers should pay attention to
▪ The glazing area size
▪ Building orientation
▪ Climate conditions
• TC glazing parameters values to obtain the best suitable scenario
• New data that lead to more accurate design strategies for low-energy office building in cooling-dominated climates
• Results could also serve as guidelines for the improvement of TC thin coating materials
▪Solar transmittance
▪Visible transmittance
▪Transition temperature
18 Future works
• Study of the optimal parameters that reduce energy and improve
comfort using optimization techniques
• Study of this method using passive cooling and natural ventilation for
office buildings in hot tropical climates
• Need to add new input, such as air flow rate and new output indexes
19
Thank you for your attention
20 BibliographyBorgonovo, E., 2007. A new uncertainty importance measure. Reliab. Eng. Syst. Saf. 92, 771–784. doi:10.1016/j.ress.2006.04.015
Bülow-Hübe, H., 2001. Energy Efficient Window Systems. Effects on Energy Use and Daylight in Buildings. Lund University, Sweden.
Carmody, J., Selkowitz, S., Lee, E., Arasteh, D., Willmert, T., 2004. Window systems for high-performance buildings. Norton New York.
CIE, S., 2002. 008/E: 2001: Joint ISO/CIE Standard: Lighting of Work Places–Part 1: Indoor [incl. Technical Corrigendum ISO 8995: 2002/Cor. 1: 2005 (E)]. Vienna Austria Comm. Int. L’Eclairage.
Costanzo, V., Evola, G., Marletta, L., 2016. Thermal and visual performance of real and theoretical thermochromic glazing solutions for office buildings. Sol. Energy Mater. Sol. Cells 149, 110–120. doi:10.1016/j.solmat.2016.01.008
David, M., Donn, M., Garde, F., Lenoir, A., 2011. Assessment of the thermal and visual efficiency of solar shades. Build. Environ. 46, 1489–1496. doi:10.1016/j.buildenv.2011.01.022
Dietrich, M.K., Kramm, B.G., Becker, M., Meyer, B.K., Polity, A., Klar, P.J., 2015. Influence of doping with alkaline earth metals on the optical properties of thermochromic VO2. J. Appl. Phys. 117, 185301. doi:10.1063/1.4919433
DOE, U., 2010. Energyplus engineering reference. Ref. EnergyPlus Calc.
Granqvist, C.G., 2016. Recent progress in thermochromics and electrochromics: A brief survey. Thin Solid Films. doi:10.1016/j.tsf.2016.02.029
Hoffmann, S., Lee, E.S., Clavero, C., 2014. Examination of the technical potential of near-infrared switching thermochromic windows for commercial building applications. Sol. Energy Mater. Sol. Cells 123, 65–80. doi:10.1016/j.solmat.2013.12.017
Li, S.-Y., Niklasson, G.A., Granqvist, C.G., 2012. Thermochromic fenestration with VO2-based materials: Three challenges and how they can be met. Thin Solid Films, 7th International Symposium on Transparent Oxide Thin Films for Electronics and Optics (TOEO-7) 520, 3823–3828. doi:10.1016/j.tsf.2011.10.053
LIANG, R., WU, Y., WILSON, R., 2015. Thermal and visual comfort analysis of an office with thermochromic smart windows applied, in: Proceedings of International Conference CISBAT 2015 Future Buildings and Districts Sustainability from Nano to Urban Scale. LESO-PB, EPFL, pp. 71–76.
Mlyuka, N.R., Niklasson, G.A., Granqvist, C.G., 2009. Mg doping of thermochromic VO2 films enhances the optical transmittance and decreases the metal-insulator transition temperature. Appl. Phys. Lett. doi:10.1063/1.3229949
Morin, F.J., 1959. Oxides Which Show a Metal-to-Insulator Transition at the Neel Temperature. Phys. Rev. Lett. 3, 34–36. doi:10.1103/PhysRevLett.3.34
Pérez-Lombard, L., Ortiz, J., Pout, C., 2008. A review on buildings energy consumption information. Energy Build. 40, 394–398. doi:10.1016/j.enbuild.2007.03.007
Saeli, M., Piccirillo, C., Parkin, I.P., Binions, R., Ridley, I., 2010. Energy modelling studies of thermochromic glazing. Energy Build. 42, 1666–1673. doi:10.1016/j.enbuild.2010.04.010
Usher, W., Herman, J., Whealton, C., Hadka, D., xantares, Rios, F., bernardoct, Mutel, C., Engelen, J. van, 2016. SALib/SALib: Launch! doi:10.5281/zenodo.160164
21 Questions and discussions
?