Tools for Integrated Design

ID seminar 24-26 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

Architecture

Energy

Daylight

Indoor climate Room

Tool development

BuildingCalc LightCalc

Thermal simulation Daylight simulation

BuildingCalc + LightCalc

iDbuildIntegrated 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

145

1

cos coss i i i suni

E L S I

n

jijjiii FBREB

1

L: patch luminance (lm/m2Sr)ΔS: solid angle (Sr)ξ : incidence angleσ: visible proportion of sky patchτ: transmittanceI: direct normal irradiance (W/m2)η: beam luminous efficacy (lm/W)

Ray-tracing Radiosity

nnnnnnnnn

n

n

E

E

E

B

B

B

FRFRFR

FRFRFR

FRFRFR

::

1...

:...::

...1

...1

2

1

2

1

21

22222212

11121111

B: radiosityE: emitted energyR: reflectanceF: form factor

WIS input

WIS input 2

WIS reportFor 10 slat angles –10 reports

New database entry

Glazing and shading database

Case

Daylight factor

100ext

in

E

EDF

10000 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

Clear double glazing

0

5

10

15

20

0 1 2 3 4 5 6

Distance from window [m]

Day

lig

ht

fact

or

[%] Radiance

LC 0.5x0.5m

Relative error: ~30%

LightCalc – sunny day

Without blinds With blinds at cut-off angle

Validation

0

2000

4000

6000

8000

10000

12000

14000

0 1 2 3 4 5 6

Distance from window [m]

Illu

min

ance

[lu

x]

Rad,illum

BC/LC tool

0

100

200

300

400

500

600

700

800

900

0 1 2 3 4 5 6

Distance from window [m]

Illu

min

ance

[lu

x]

Radiance

BC/LC tool

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 airHeat 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/ortoo much light?

Shading is lowered

Blinds are adjustedto cut off angle

Simulation hour t

yes

Is it still too hot?

Simulation hour t+1

yes

no

no

Excesstemperatures

If specified:1. Windows are opened

2. Ventilation is increased3. Cooling is started

BC+LC results

BC+LC results

BC+LC results

Hourly values1st week of January

Integrated values

Validation

iDbuild

CapabilitiesSystematized parameter variations

using BC+LCPresentation of variation results

LimitationsStill too slow

Parameter 2

Parameter 1

Method – setup

Variation 1 Variation 2ReferenceParameter 3

Variation 1 Variation 2Reference

Reference

Lower value Higher valueReference valueNo of

simulations:

1

3

5

Referencesystems

Var.1systems

Var.2systems

Method – work flow

Decide on a reference

Decide on whichparameters

we would like to change

Enter values forvariation 1 and variation 2

Click simulate

Evaluate results

Repeat with newreference if desired

Method – results

Results

Param.1 Param.2 Param.3

Var.1Refer. Var.2

Var.1 Var.2Refer.

One parameter variation

One parameter variation

Case

Case

4x6x3 m room with 2 persons

Window height(above working plane)

Shading

1.2m 2.0m1.6m

Dbl glz

Variation 1 Variation 2Reference

Dbl glz w/ext blinds

Dbl glz w/AntiSun

Cooling MechanicalNight

coolingNo cooling

Evaluation settings

What should we measure the results up against?

Winter: 21-23CSummer:

23.5-25.5C

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.

NoneNight

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

PrerequisitesInstallation of runtime libraries

~100MBOr Matlab technical programming

language We are now in version 2.5.1 but are

constantly improving Version 2.6 is expected to be faster