The role of simulation tools in design process

Teet TarkHevac OÜ

Chairman of the Board

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– El

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ics

HVAC

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1800…1980 1970…1995 1990…2010 2000…

Calc

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ons

Draw

ings

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Building Information Model

2100…

• Probably none of us can imagine how to design the building without the use of computers and specialized software

• Are there many Engineers and Architects nowadays, who would be able to design the building without the use of computers?

What shouldn't be forgotten and what should be considered

• Does the person performing the simulation actually knows the logics and principles of the particular software, its default values and how reliable are the results?

• The person performing the simulation should have the fundamental knowledge in this field.

• The simulation software should not be a “black box” where the user only enters the initial data and after a while gets the results. The user has to understand what is the reason for particular simulation outcome, what influences the results?

• Among the designers, one quite common answer to the question “How did you get this value?” is “This was calculated in XXX software.” However, if someone doubts in the calculation results due to them not being realistic, then those who performed the calculation defend their position believing that the calculation is right, because the results was obtained thanks to simulation software.

Simulation results depend on the performer, his skills, approach etc.

-20,6 % -33,6 %

Results interpretation

XXX YYY0.0

20.0

40.0

60.0

80.0

100.0

120.0100.8 96.6

EPV

Design Company

EPV,

kW

h/(m

2.a)

XXX YYY0.02.04.06.08.0

10.012.014.016.018.020.0

11.6

5.7

6.1

10.1Cooling electricitySpace heating

Design Company

Com

pone

nt o

f EPV

, kW

h/(m

2.a)

1,04 times

0,6 times

2 times

How reliable are the results obtained with the simulation software ?

Measured room temperature

How reliable are the results obtained with the simulation software ?

Design Examination 0

500

1000

1500

2000

2500

1670

2100

Cool

ing

load

, W

Designer’s simulation software:• Depending on the simulation model location (including Tallinn), the software applied

solar radiation reduction coefficient (clearness of sky) 0.75.• The cooling load design considered the calculation at the date set to the most sunny

day and the duration of sunny period was 2 days. Though, in real environment the duration of the sunny period is significantly longer, the building structure manages to warm up more than expected and this produces a higher cooling load.

The software manual had no information about the settings described above. Therefore, the designer could not even know that.

The cost of the additional cooling equipment was ca 50 000 €. Insurance refused to compensate the damage.

SOFTWARE LICENSE AGREEMENT

The software company is never liable for anything: read the license agreement

The results of the calculations for the building being designed depending on the software being used

0

10

20

30

40

50

60

Space heating Space cooling

Net e

nerg

y co

nsum

ptio

n, k

Wh/

(m2*

a)

BV2

IDA-ICE

Riuska

Bsim

VIP Energy

Source: H. Voll, T. Tark 2010. Energiatõhususe miinimumnõuete tõendamise ja selle kontrolli võimekuse tõstmine

B I MBuilding Information Modelling

IThe "I" is commonly forgotten

A common understanding of BIMpurpose is:• 3D visualisation• Structure and HVAC interference

check• Structure voids/openings position

evaluation• Equipment and materials

quantification/schedules

Discipline specific software interoperability

Building refurbishment

• Integrated B I M application is rather problematic– The digital surveying may produce only the 3D model of the

visible parts– In example, there is no information about wall construction:

• What are the wall layer materials?• Where are the reinforcement bars located?• Where are lintels located?

– Building services designer cant do much with the visual information, he is more interested, for example, in:

• Equipment parameters, materials, mark of equipment, what is inside the electrical panel, control and automation etc.

Summary• The increase of the calculations accuracy• Acceleration of the design process• Evaluation of various design performance• Design optimization• Results visualization• The person performing the simulation should have the

fundamental knowledge in this field• The simulation software should not be a “black box” • The risks should be assessed, the responsibility should be

considered