Tools for Integrated Design ID seminar October Christian Hviid Industrial PhD-student Birch & Krogboe

Agenda Tools package LightCalc Technicalities Glazing and shading input from WIS Combined BuildingCalc and LightCalc Technicalities Controls: daylight, glare (blænding), temperature iDbuild Parameter variations Tool for integrated design Live show

Complexity Room

Tool development BuildingCalcLightCalc Thermal simulation Daylight simulation BuildingCalc + LightCalc iDbuild Integrated Design of Buildings

Development objectives Room level Quick and intuitive input Accuracy comparable with much more advanced programs High calculation speed Facilitates consequence-guided design process

Look and feel

LightCalc Capabilities Daylight on room level Standard overcast sky or weather data Accepts material input from user or from Window Information System (WIS) database European glazing and shading products A quick tool for daylight design Limitations One room model, one window

Skies Sky subdivision Up-side down sky for ground reflectance The Perez sky model is a mix of clear, intermediate, and overcast sky created directly from weather data.

Technicalities L: patch luminance (lm/m 2 Sr) ΔS: solid angle (Sr) ξ : incidence angle σ: visible proportion of sky patch τ: transmittance I: direct normal irradiance (W/m2) η: beam luminous efficacy (lm/W) Ray-tracing Radiosity B: radiosity E: emitted energy R: reflectance F: form factor

WIS input

WIS input 2 WIS report For 10 slat angles – 10 reports

New database entry

Glazing and shading database

Case

Daylight factor lux outside and 200 lux inside is a DF 2% A standard for measuring daylight friendly design

LightCalc – overcast day Calculation time: ~1min on Pentium M 1.8Ghz With overhang Without overhang

Validation Relative error: ~30%

LightCalc – sunny day Without blinds With blinds at cut-off angle

Validation Relative error: ~20% Relative error: ~10%

BuildingCalc + LightCalc Capabilities Energy consumption on room level Separate ventilation, heating, cooling, lighting Indoor thermal climate Hourly values for daylight Multiple possible system controls daylight, glare, temperature, natural ventilation A tool for integrated daylight and thermal design Limitations One room model, one window

Technicalities Thermal node model Temp. in the wall Wall surface temp. Air temp. Ext. temp. Heat gain to air Heat gain to building structure

Shading control Overhang, blinds, screens Slat angle, β Outside Inside Slat distance, d Slat width, w Profile angle, p Cut-off angle

Glare control Glare is almost directly related to the amount of daylight the occupant receives in the eye A threshold of 20% means that 20% will be disturbed

Control flow Is it too hot and/or too much light? Shading is lowered Blinds are adjusted to cut off angle Simulation hour t yes Is it still too hot? Simulation hour t+1 yes no Excess temperatures If specified: 1.Windows are opened 2.Ventilation is increased 3.Cooling is started

BC+LC results

Hourly values 1st week of January Integrated values

Validation

iDbuild Capabilities Systematized parameter variations using BC+LC Presentation of variation results Limitations Still too slow

Parameter 2 Parameter 1 Method – setup Variation 1 Variation 2 Reference Parameter 3 Variation 1 Variation 2 Reference Lower value Higher valueReference value No of simulations: Reference systems Var.1 systems Var.2 systems

Method – work flow Decide on a reference Decide on which parameters we would like to change Enter values for variation 1 and variation 2 Click simulate Evaluate results Repeat with new reference if desired

Method – results Results Param.1Param.2Param.3 Var.1 Refer. Var.2 Var.1Var.2 Refer. One parameter variation

Case

4x6x3 m room with 2 persons Window height (above working plane) Shading 1.2m 2.0m 1.6m Dbl glz Variation 1 Variation 2Reference Dbl glz w/ ext blinds Dbl glz w/ AntiSun Cooling Mechanical Night cooling No cooling

Evaluation settings What should we measure the results up against? Winter: 21-23C Summer: C 1.5 L/s pr m2

Window parameters

Cooling parameters Mechanical cooling

Results – glazings Clr dbl glz Ext blinds AntiSun

Energy and comfort

Results – window height

Results – cooling Mech. None Night

Energy and comfort Cooling is required in winter to keep temperature below 23C…

Final results

Conclusion on case For the specified indoor climate parameters: Use external shading Use window height of 1.2m And handle the overheating with night cooling The sum ≠ one parameter + another param. Achieving low-energy class 2 for offices is not easy, but this is the only way for no extra costs… Is a temperature range of 2°C for indoor class I not too strict with regards to energy?

Limitations Mixing multiple parameter variations requires multiple references If the effect of two variations are opposite, it is invisible before another reference has been made System variations have to be made separated from the rest of the variations ( in line for changes… )

Additional info Prerequisites Installation of runtime libraries ~100MB Or Matlab technical programming language We are now in version but are constantly improving Version 2.6 is expected to be faster