i | P a g e

A COMPARATIVE OF INNOVATIVE ENERGY MODELLING

AGAINST CONVENTIONAL METHODS AND THE USE OF BIM TO

ASSIST IN IMPLEMENTING

By

David Austin

1102747

Architectural Design Technology

School of Technology

University of Wolverhampton

Supervising Officer: Dr David Heesom

Date January 2015

ii | P a g e

Presented in partial fulfilment of the assessment requirements for the above award.

This work or any part thereof has not previously been presented in any form to the

University or to any other institutional body whether for assessment or other purposes.

Save for any express acknowledgements, references and/or bibliographies cited in the work,

I confirm that the intellectual content of the work is a result of my own efforts and no other

person.

It is acknowledged that the author of any project work shall own the copyright. However,

by submitting such copyright work for assessment, the author grants to the University a

perpetual royalty-free license to do all or any of those things referred to in section 16(i) of

the Copyright Designs and Patent Act 1988. That is, to copy the work; to issue copies to the

public; to perform or show or play the work in public; to broadcast the work or to make an

adaption of the work.

i

UNIVERSITY OF WOLVERHAMPTON

ABSTRACT

A comparative of innovative energy modelling against conventional methods and

the use of BIM to assist in implementing

By David Austin

Supervising Officer: Dr: David Heesom

School of Technology

With strategies such as the 2025 construction strategy and 2016 building information

modelling target being recently developed, it has emphasised the focus on overcoming

inefficiencies in relation to energy usage both in the manufacturing and running of projects.

Inevitably this has led to scrutiny in achieving the optimisation of energy efficiency in a

design, this optimisation requires extensive design and analysis at the conceptual stage to

ensure the best solution is concluded avoiding unnecessary cost from post design

alterations.

This study investigates advancements of energy modelling against conventional methods to

present an overview of how the methodology that forms the basis of each study has evolved

to coincide with the advancements in technological resources available. Direct analysis is

used to compare the ‘traditional’ methods with the emerging approaches. The concluding

verdict of this analysis illustrates that within the construction industry the use of the new

ii

innovations offer a more practical and effective option. These options allow quick and

accurate analysis to be achieved in a less time and cost intensive method. These methods

over time will inevitably evolve as the technology available does to ensure even quicker and

cheaper solutions that will offer further in-depth extensive analysis.

iii

ACKNOWLEDGMENTS

The author wishes to express sincere appreciation to Dr David Heesom for his assistance in

the preparation of this manuscript.

iv

TABLE OF CONTENTS

Abstract .........................................................................................................................................i

Acknowledgements ................................................................................................................. iii

Table of contents ..................................................................................................................... iv

Table of figures......................................................................................................................... vi

Section 1: Introduction ........................................................................................................... 1

1.1: A general overview of the advancements of the BIM process ............. 1

1.2: Historical advancements of BIM and energy modelling ........................ 2

1.3: The future of energy modelling within BIM ............................................. 4

1.4: The importance of energy modelling within the initial ......................... 5

design stages

1.5: Aims & objectives ............................................................................................ 6

1.4: Organisation of the report ............................................................................. 7

Section 2: Wind tunnels vs computational fluid dynamics ............................................ 8

2.1: Introduction......................................................................................................... 8

2.2: Wind tunnel studies ........................................................................................... 9

2.3: Wind tunnel studies-the methodology ....................................................... 11

2.4: Computational fluid dynamics studies ....................................................... 13

2.5: Computational fluid dynamics-the methodology .................................... 13

2.6: A comparative analysis of wind tunnels & CFD’s .................................. 16

v

Section 3: Heliodon vs geo-located solar studies ........................................................... 18

3.1: Introduction .............................................................................................................. 18

3.2: Solar studies-the methodology ............................................................................ 19

3.3: Solar studies-the advantage of its use ................................................................ 21

3.4: Heliodon studies ...................................................................................................... 22

3.5: Geo-located solar studies ...................................................................................... 24

3.6: A comparative analysis of heliodon’s & geo-located solar studies ........... 27

Section 4: Conclusion ............................................................................................................ 29

4.1: The use of CFD’s for wind utilisation .............................................................. 29

4.2: The use of geo-located solar studies for solar utilisation ............................. 30

Bibliography ............................................................................................................................. 32

Appendix A. ............................................................................................................................. 36

vi

TABLE OF FIGURES

Figure Page

1: Glodon BIM overview ....................................................................................................... 1

2: BIM and the building lifecycle .......................................................................................... 2

3: The flow of air in an urban area ..................................................................................... 11

4: An example of a wind tunnel used for Chifley Square, Australia ......................... 13

5: An example of a vector plot representing a turbulent flow .................................. 16

around a sphere

6: An example of a x-y plot representing the temperature in .................................... 16

comparative to wind speed

7: An example of a solar path diagram representing the sun ...................................... 21

path over a 6 month period

8: An example of a typical heliodon ................................................................................. 24

9: An example of a geo-located solar study analysing solar ........................................ 27

radiation, shadowing and exposure

1

S e c t i o n 1

INTRODUCTION- A GENERAL OVERVIEW OF HOW THE BIM

PROCESS COINCIDES WITH ENERGY MODELLING

A general overview of the advancements of the bim process

It is often conceived that BIM is simply specialised software that has frequently been used

predominantly in the Engineering discipline with only recent adoption by other members of

the Construction industry, e.g. Architects and Contractors (Heesom. 2014.) However as

shown in both Figure 1 & 2 it is much more than a software package that is used to design,

it is in fact a workflow process that relies entirely on full collaboration of all disciplines.

Figure 1: Glodon BIM overview (Glodon. n.d)

2

This process covers all aspects of the design process to allow full production of all necessary

documents from conceptual design through to fabrication documents and finally an

Operation & Management database. As this flow progresses through the stages, relevant

documentation will be produced at each stage to reflect the revised RIBA plan of work

(2014).

Historical advancements of bim and energy modelling

As described by Bergin and Quirk (2012) the BIM process story is a ‘Rich and Complex’

one which consists of various key roles within it. As stated within the article the first

conceptual prospect of BIM was anticipated by Englebert (1962) where in his paper

‘Augmenting Human Intellect’ he described the future being a person designing on a screen

with elements that could be projected to a 3D model, both allowing for evaluations and

adjustments to suit. During the following 60 years there were vast advancements from the

Figure 2: BIM and the

building lifecycle

(Hegedus. 2012)

3

initial concept that was presented by Englebert which have both lead to a structured work

flow as well as the creation of various software’s.

Whilst the BIM process was being developed there were also developments in Building

Energy Modelling. Building Energy Modelling can be traced back to 1925 with the

development of foundation algorithms such as Nessi and Nisolle’s Response Factor

Method which was the initial model for heat flow, however it was not until the 1960’s with

various documents produced by Mitalas and Stephenson that this method was used for

studies in heat transfers through walls which was the starting point of energy modelling

studies (Haberl & Cho. 2004).

In 1959 the American Society of Heating, Refrigerating and Air-Conditioning Engineers

(ASHRAE) was formed as a body in the United States that have pursued the optimisation

of mechanical services. During the 1960’s the body dedicated vast amounts of resources to

create computerised systems for both building management and calculations of air

conditioning, these later formed procedures for the calculations of heating and cooling.

Following the completion of these procedures there was the First International Building

Performance Simulation Conference that led to the development of substantial steps in

software development including the creation of packages such as TRNSYS (1975), Bentley

BIM (1997) and Revit (2010). These packages have enabled energy modelling to occur on a

computer interface as opposed to the standard ‘hands on’ approach previously used. This

4

was further enhanced with the development of gbXML file formatting in 2000 to allow the

information to be transferred around the design group when needed, following the basic

principle of collaboration in BIM between disciplines as previously discussed (Haberl &

Cho. 2004). An in-depth timeline portraying the history of Building Energy Modelling can

be found in Appendix A.

The future of energy modelling within bim

BIM has already become a common practice within the construction industry with it being

extensively used prior to the Level 2 BIM requirement issued in the Government

Construction Strategy (BIS. 2011). Although energy modelling is widely used already it has

not been enforced as a requirement, therefore the majority of new builds do not do

extensive model analysis but instead use conventional design methods that save energy

instead of further exploring whether this can be improved.

As large international companies such as HOK, Arup and Kier start to adapt BIM fully and

with companies such as Autodesk supporting the energy analysis side of modelling, it

appears to a realistic expectation that in the near future companies will be using the energy

analysis tools on all projects ranging from a small residential build to a high rise office

building.

5

The importance of energy modelling within the initial design stages

It is considered that by 2025 the construction market will grow by over 70 %, (DECC.

2013) with this substantial growth it will directly correlate with an increase in carbon

emissions, however it has been also been stated by the DECC that there is a target of 80%

reduction on carbon emissions by 2050 (DECC. 2013). In order to pursue this target it is

necessary for the construction industry to use innovative design methods that will both

reduce waste both during and post construction, as well as ensure high efficiency operation

of the building post to completion.

Energy modelling can be a key element to pursuing the emission target set by the

government as it is a process that can occur prior to formal decisions being made and can

present various options with their proposed outcomes in relation to energy usage, savings

and improvements. The use of methods such as wind and solar studies allow the design

team to analyse a concept over a set amount of time to see how it reacts to an accurate

portrayal of the environment it will be in and scrutinise where it can be improved before it

is taken to detailed design.

As stated in the Energy Efficiency Strategy ‘We estimate that through socially cost effective

investment in energy efficiency we could be saving 196TWH in 2020, equivalent to 22

power stations’ (DECC. 2012). Although the focal point for this initiative is the use of

innovative construction methods opposed to the initial design, it is essential to use energy

6

modelling at the forefront of the design to optimise the building from the beginning of the

concept.

7

Aims and objectives:

The aim and objectives for this report are outlined below:

Aim: The aim of this report is to explore emerging methods of energy modelling and their

effectiveness in comparison with conventional modelling methods whilst analysing a

building at concept stage.

Objectives: In order to meet the aims of the report the following items will need to be

analysed:

The importance of energy modelling methods and the theory behind the modelling

method

The ‘conventional’ methods of energy modelling analysis

The emerging methods that can be used as an alternative

A comparative study of the conventional method versus the emerging

Case studies analysing the effective implementation of the methods and their

alternatives

8

Organisation of the report

The report will consist of a comprehensive study of the following energy modelling

methods:

Wind tunnels vs CFD’s

Heliodon vs geo-location solar studies

U value calculators vs energy analysis modelling

Within these chapters there will be a thorough analysis of the methodology that has defined

these studies as well as a comparative study on their effectiveness in relation to the area of

study.

The results of the comparative study will form the basis for the design of Bilston Primary

School using the effective methodology discovered to influence the design in respect to

wind flow through the site, the orientation for solar influence and effective design for

energy efficiency.

9

S e c t i o n 2

WIND TUNNELS VS COMPUTATIONAL FLUID DYNAMICS

Introduction:

It was discovered in a study undertaken that out of a measure of 356 public buildings 50%

of these possessed improper ventilation which had a direct effect on the welfare of the

users. This was referred to as ‘Sick Building Syndrome (Wallingford, Carpenter. 1986).

Following this study it has become an important aspect to be considered in the design stage

with the implementation of Building Regulation Approved Document F to reinforce the

need for adequate ventilation with appropriate guidance in how to achieve this.

In addition to this document there are further readings in relation to sustainability that

discuss various aspects including ventilation, these further readings include various BRE

guides. As stated within the Design Quality Buildings: A BRE guide (BRE. 2006) designers

should consider the following aspects during the design process:

Occupants and passer-by are not subject to wind funneling effects

The structure of the building should be designed to withstand wind pressure, water

penetration and wind loading

10

The orientation of a building directly effects ventilation and natural light. Careful

consideration of this is key to comfort, avoiding deterioration and cost saving

Local effecting influences such as altitude, ground level, topography, speed and

direction of wind, season, location and terrain

These considerations if explored correctly inform the design process to create an effective

solution that will promote ventilation in and around the site.

During this design process the use of analytic methods for wind flows has been commonly

explored, especially in projects with high rise buildings and turbulent wind conditions. The

use of these methods have allowed the simulation of various wind conditions to be applied

to a mass to portray how elements such as vortex’s (a spinning formation of air) and wake’s

(an area of no movement behind an obstruction) would be effected by both varying

conditions and making alterations to the mass itself. In addition to this the systems used for

analysis allow for adjustments to be created to accurately mimic the site conditions correctly.

Wind tunnel studies

Wind tunnel studies have been predominantly used throughout the engineering discipline

with particular usage in automotive and aircraft design analysis. However between the

1940’s and 1950’s the use of this technology was first used in analysing the effects of wind

flow on a building using the typical wind profiling found in the atmosphere, uniform and

11

velocity profiles (Blackmore. 1997). Although this method had been used frequently in

other disciplines it was discovered in the 1960’s that the tunnels did not possess an accurate

portrayal of the atmospheric layer. This layer in the real world circulates 1km above the

surface and circulates around the circumference. As a building is erected it will penetrate the

layer and create a 3D flow to which fluctuates the results previously, the effect of this

penetration on the layer is shown in Figure 3 below. In order to recreate this, devices were

created to obstruct the flow and create the necessary accurate atmosphere (Lawson. 2001).

Figure 3: The flow of air in an urban area (Cengiz. 2013)

12

Lawson describes one of the functionalities of a wind tunnel investigation as a means of

testing pressures on a building (Lawson. 2001). However, wind tunnels offer much more

information including the data and visuals that are produced testing turbulences, velocities

(mean and fluctuating) and flows (Scanlan. 1978). These vital pieces of information can help

a designer understand the reasoning behind the results. As mentioned, one of the elements

that is measured during the investigation is the assessment of wind speeds at a pedestrian

level using either an Irwin Probe (a tube that measures the pressure differences from the

base to the top to calculate velocity) or Hot Wire Anemometer (2 thin pieces of wire that

run electric current through to measure the cooling that occurs when a flow passes

through). This study then allows measures to be implemented in the massing of the model

to tackle any issues of turbulent flow that may occur.

Wind tunnel studies- The methodology

The basic principle behind a wind tunnel is the use of large scale industrialised fans within a

tunnel environment to simulate the flow of wind that would be experienced in real world

situations. However due to the wind fluctuating in profile the use of flaps, shutters, grids

and fences are used to mimic the different profiles that may occur with adjustments being

controlled via specialised computer software (Scanlan. 1978), an example of a typical tunnel

can be seen in Figure 4. These simulations can then be transposed into either data or visuals

depending on the desired outcome required, for instance a smoke photo may be used to

13

show the flow of the wind where as a x-y plot may be used to show the fluctuation of

velocity (Tu, et. al. 2012).

Figure 4: An example of a wind tunnel used for Chifley Square, Australia (National

Instruments. N.D)

14

Although the use of wind tunnels has been perceived as an accurate solution to modelling,

with examples of uses including the development of aerodynamics for fighter jets, this is

often a perception that is not entirely correct. Due to the restriction in sizing for the tunnels

it is difficult to mimic the requirements for aspects such as the correct flow in relation to the

Coriolis Effect (the rotation of wind flow to compensate for the earth’s rotation and heat

flow) (Scanlan. 1978) and the creation of a correctly scaled velocity in respect to the scale

model used (Lawson. 2001). In addition to this the data produced for these simulations can

only run for a short duration not allowing full month or year analysis.

Computational fluid dynamic studies

Computational fluid dynamics (CFD) is a methodology that has been used throughout the

aerospace, automotive, biomedical, civil and environmental engineering disciplines. The

basic principle behind this simulation is the translation of mathematic fundamentals used in

wind tunnels to create virtual profiles that can be represented as flows in computer

simulation (Tu, et. al. 2012). These simulations are run for a time lapsed amount of time to

determine factors such as air velocity, flow rate, air pollution and thermal balancing within a

building (Athenitis, Santamouris. 1986).

Computational fluid dynamics- The methodology

Unlike the wind tunnels, the steps of creating a CFD revolve solely around the use of

computer software to create the geometry and meshing of the building before specifying the

appropriate physics and boundary layer to run simulations with. As mentioned previously

15

the use of a CFD method can allow for multiple testing to be simultaneously ran for various

scenarios, something a wind tunnel cannot do without multiple tests (Tu, et. al. 2012). In

addition to the creation of a simulation much like the wind tunnels there is also the

additional features that a CFD offers including the creation of a Dynamic Simulation Model

(DSM) to create time lapsed visualisations of the simulation for review including:

Vector Plots (Velocity presented in arrows for flow direction with size relative to

magnitude)

X-Y Plots (A chart representing various comparatives such as fluctuation in velocity,

temperature in comparison to wind speed as well as various others)

Flooded Contour (Much like a thermal image it portrays data in colour for severity)

Streamline Plots (A representation to show the wake recirculation zones)

Data Reports

Further to this there is also analysis that can be undertaken in a model on additional aspects

such as internal ventilation, temperature and CO2, something wind tunnels are unable to

produce (Jankovic. 2012).

16

Although there have been issues with CFD’s producing errors that may have looked correct

in the visuals but the data has not quantified correctly (Tu, et. al. 2012), the advantages have

by far outweighed the initial issues as the approach is adopted by construction. As described

in Computational Fluid Dynamics (Tu, et. al. 2012) the advantages include:

The ability to study specific terms within a fundamental equation to conclude why a

result has acted how it has

Simulate real fluid flows using a low cost and low time consuming method

Figure 5: An example of a vector plot

representing a turbulent flow around a

sphere (TVT. 2011)

Figure 6: An example of an x-y plot

presenting the temperature in

comparative to wind speed (UCLA. 2007)

17

Simulate various scenarios using the same model simultaneously

Creation of visualisations that are able to be reviewed by the team and presented

externally

Evaluation a range of parameters

Allow temperature to be shown in addition to the flow of the air

A comparative analysis of wind tunnels & CFD’s

Overall the essential methodology behind wind tunnels and CFD’s are the same with only

variations on the creation method of the model and the presentation of the results. With

this being said, CFD’s have followed the common trend of utilising an ever evolving

computer age which saw hand drawings develop to 2D and now 3D integrated design

methods. With this age it has allowed a time and cost consuming method of wind tunnels

be transformed into a simplified computer interface that summaries the decades of

development for the wind tunnel to allow a model to be created, tested, analysed and

adjusted in a much less cost and time consuming exercise.

In addition to this as the use of CFDs is still developing as they are adapted further by the

construction industry, and with computers becoming more capable of dealing with large

algorithms, the use of this method has great promise in becoming a more efficient and

predominant use for air flow studies as it offers more functionality in relation to various

studies that a wind tunnel cannot offer. However, much like the automotive industry the use

18

of wind tunnels will still be coincide with the computerised alternative as they both

complement each other and ensure a convergence in data.

19

S e c t i o n 3

HELIODOM VS GEO-LOCATED SOLAR STUDIES

Introduction:

The use of the sun as a guiding element for building position and orientation has been dated

back as far as the Classical Greek period (500-336 B.C) with observations being

documented by Socrates. During his time as a philosopher he noted that in the summer

seasons houses with a southern orientation would allow sun rays to penetrate the porches

whilst in the winter the sun would pass overhead and create a shaded area (Perlin. 2013).

These observations have developed over the following 2,500 years to create the principles

behind Passive Solar Design:

Orientation

Shading

Passive solar heating & cooling

Sealing the building

Insulation

Thermal mass

Glazing

20

Skylights

(Australian Government. 2013)

Each of these principles is an aspect that needs to be taken into consideration at the

concept stage of design to optimise the buildings utilisation of the sun throughout the year,

as stated within Introduction to Architectural Science: The Basics of Sustainable Design ‘To

effectively design the designers need to understand the movement of the sun and the energy

flow and has to handle it’ (Szokolay. 2003).

In order to assess whether the design has used the principles effectively, the use of solar

studies is required to measure the scheme and assess it in regards of areas that could be

improved. The use of solar studies has been extensively used throughout architectural

design for many years with it now becoming more predominantly used as sustainable design

has become a key aim within projects.

Solar studies-The methodology:

As previously mentioned the use of the sun’s rays as a method of natural lighting, heating

and shading has been commonly used since the Classical Greek period. As shown in Figure

7 the sun follows an orbiting path that varies according to the seasons, these variations see

the summer period sun path to be 23.45 degrees higher than the central line and 23.45

21

degrees lower than the central line in the winter period. This is a presented as a two labelled

curved lines in Figure 7. As shown, the winter line is a less curved line which translates to

less day light hours at a lower angle; whereas the summer line is more curved at a higher

angle presenting more solar rays exposure. These sun paths are presented in solar path

diagrams that are unique to each site as they coordinate the site longitude and latitude with

the date and timing.

Figure 7: An example of a solar path diagram representing the sun path over a 6

month period (System Site Buildings. 2010)

22

The solar path diagrams are then analysed to create the site environment, either manually or

digitally, before a model is tested, analysed, altered and tested again until the solution

resembles the objective sought for originally.

Solar studies-The advantages of its uses:

It has been observed that designers often rely on “rules of thumb” and their own

experience to make decisions on designs, however this can be misinformed and result in

errors (Lam.1999 cited Osser. 2007). Therefore the use of solar studies at the forefront of

the concept design is vital to ensure problems are discovered at an early stage to avoid issues

that can cost time and money, the use of these studies could potentially present where there

could be issues of glare to the users, inadequate lighting and shadowing.

An effectively designed building can both exploit the solar gains presented on the site whilst

ensuring the comfort of the users is maintained. As Hawke (1996) described, an effectively

orientated building ‘can receive sufficient amount of passive solar gain to offset the heat it

will lose’. In addition to the reduced need for heating due to the solar offset, the effective

design can also reduce the need for electric lighting which will in turn reduce the amount of

heat produced by these elements (Demetriou. n.d).

As mentioned previously the exploitation of these gains can also ensure the comfort of the

users, studies have shown that:

23

Good use of daylight and sustainable design can raise rate of production by 1%

Increase productivity, improve health, lower absentee rate, create better grades

Improve the moods of the users

(Krygiel, Nies. 2008)

Heliodon studies:

As mentioned earlier, the sun follows a certain path dependent on the date, time and

location, the use of a Heliodon can mimic this precisely to create a simulation of how the

sun will react to on the building and its surroundings. A Heliodon can vary in its

appearance; however the basic principles behind them are always the same. As shown in

Figure 8 it consists of a table that houses the scaled model; this is orientated correctly to

ensure the buildings true north corresponds with the tables true north, attached to the table

are 6 rows of lights (each row corresponding to a period of the year) which each have 12

lights representing the hours of the day that are light. As the light varies site to site the lights

are adjustable to account for the location of the site on the hemisphere.

24

The Heliodon has progressed over time with

the first models using a simple light that

allowed the table to revolve around it,

however over time this has seen the

development to a stationary table that has

revolving light units to mimic the seasons

and time. This has further progressed with

institutes such as MIT and EPFL creating advanced systems. MIT has developed an

automated tabled system that works using a control interface to mimic lighting conditions

of a location, time and date with camera facilities to document the findings (Osser. 2007).

EPFL have kept to the typical Heliodon with a static model, however they have created a

116th scale artificial sky ratification to mimic the sky conditions. Due to this environment

being so large it is capable to house larger models which can house sensors that can be

monitored and evaluated (Szokolay. 2003).

The use of a Heliodon as a tool in the solar studies on a building present various advantages

including:

They allow the user to move around the model in real time to see how it affects areas

Figure 8: An example of a typical

heliodon (HPD. 2008)

25

A crude model can be analysed for summer, winter and spring/fall far more

efficiently and affordability than its digital equivalent

The analog tools are generally more intuitive and transparent allowing people to use

them easier and comprehend the data

(Canadian Architect. n.d)

Although there are these advantages for the use of a Heliodon there are also disadvantages

that need to be considered:

Fragility needs to be considered for physical models as delicate pieces get attached

and removed and breakages can occur (Osser. 2007)

The Heliodon cannot replicate cloud cover which can affect effectiveness drastically

(Szokolay. 2003).

Over simplification based on mean temperatures used can conceal true detail

(Szokolay. 2003).

A compromise of size of the building to be tested as the building requires to be scaled

down to fit the facilities, this does not properly portray the intensity of light or heat

and does not fully show areas of concern (Cheung, Chung. 2001)

Geo-located solar studies:

Much like CFD’s geo-located solar studies revolve solely around the use of specialised

software’s, the use of these software’s can either replace or aid the typical manual Helidon’s

26

that have been used previously. These software’s include developments by various leading

producers including Bentley and Autodesk, unlike the Heliodon’s the use of the software

offer more extensive options of what can be analysed including:

Solar studies- Daylight and shadow effects over a short and long duration presented

as an animation

Solar radiation analysis- Study of solar radiation on selected surfaces

Conceptual Energy Analysis- Create an energy model for analysis of thermal zones

and adjustments based on results

Thermal analysis- Heat loss and gain, loading and comfort levels

Creation of vertical sky component’s to calculate adequate lux levels through

windowed areas

(Horvat, Wall. 2012)

The principle behind a digital solar study remains the same as the Heliodon; however the

technique behind the study is more advanced than the manual alternative and therefore

offers more in-depth and accurate analysis. Much like the Heliodon, a model needs to be

created that will be situated within a site area with the appropriate massing surrounding the

site, this remains the same with the digital alternative however as the interface has an infinite

drawing plane it is able to create a scale model of the site and building creating more

detailed and accurate results.

27

Upon completion of the model, much like the Heliodon, the conditions of the site are

created to mimic the daylight over a period of time. Unlike the Heliodon the software uses

Geostationary Satellite data to produce the weather simulations used, these data files can

account for issues such as aerosols, ozone deterioration, Rayleigh scattering and cloud

effects (Min-Yeom, Soo-Han. 2009). This sophisticated data allows future predictions to be

made over average assumptions which allow life time analysis to be achieved in a relatively

short period of time and effort (Jankovic. 2012).

Figure 9: An example of a geo-located solar study analysing solar radiation, shadowing

and exposure (SHC. 2012)

28

The use of Geo-located solar studies has been proven to be advantageous in the

development of a scheme with examples such as The Greenland National Institute. This

institution used a ‘rule of thumb’ approach when designing the scheme with large windows

being south facing to utilise the sunlight and theoretically the heat gain. Although, due to the

site being located in a cold climate the heat generated from solar gain did not equate to the

loss from using a poor insulating material such as glass (Szokolay. 2003). Issues such as

these would not have been picked up on a Heliodon simulation as this type of test would

solely focus on the light exhibited on the building yet if a computerised alternative was

produced it would have shown the issue prior to construction.

Although the use of the digital simulation offers many advantages over the manual former

method there are disadvantageous that need to be considered. The first main issue is the

time consumption that needs to be given into producing the model as each element needs

to be created individually in order for an accurate analysis on issues such as temperature

transference. This time consumption is completely dependent on the competence of the

user and the complexity of the scheme. Another issue that has become more relevant in

recent past is the inability of software’s to deal with complex surfaces, particularly curved

and shiny surfaces. These have seen issues such as glare not being correctly identified in

activity areas (Osser. 2007).

A comparative analysis of heliodon’s & geo-located solar studies

29

Although the use of a digital alternative is often perceived as a better solution for means of

simulations, the use of both methods presents both advantages and disadvantages. The use

of a physical model can be perceived as an easier method as it is a group of simple forms

orientated correctly with a preset apparatus presenting a visualisation. This being said the

results from this are limited to a simple visualisation whilst a digital counterpart could

present more in-depth analysis in respect to light, shade, energy analysis etc but take more

time to produce.

A study was undertaken by Osser that used both the method of a Heliodon as well as

Autodesk’s Ecotect on the same scheme. This study showed that the size and scale of the

model as a physical piece did not allow for a full thorough investigation, yet the use of

Ecotect allowed a comprehensive study with presentable data. Although this would seem to

show the digital alternative as the better option it was stated that due to the complexity of

the software it would require an experienced user or result in errors being made that would

affect all data produced (Osser. 2007).

In order to successfully test and present a project it will require both methods to be

undertaken, as stated by Osser and Raselin (2007) the use of a digital model and visuals are

hard to present to the cliental as they require explanation to interpret, whereas the Heliodon

allow the clients to walk around them and see firsthand the impact on the structure. The

ideal solution therefore would be to use a scale model for client presentation whilst creating

digital models for testing and calculating.

30

S e c t i o n 4

CONCLUSION

Following the study into the various aspects of design that should be analysed and the

effectiveness of the methods for analysis it has proven how essential the incorporation of

these test at the forefront of the design and how they can ensure errors are reduced that will

effectively save time and money.

The Use of CFD’s for wind utilisation:

The study of wind behaviour on an object is often perceived as something that is purely

focused at the design of automotive and aerodynamic projects, but without careful

consideration of this aspect on a building it could result in a number of issues such as

insufficient ventilation, excessive wind flow at pedestrian level or suction around edges

causing velocity.

In order to effectively implement good practice in relation to wind loading of the building

the scheme will be formed to optimise streamlining from a prevalent face and channel this

flow towards the natural ventilation channels that will be incorporated in the scheme. In

31

addition to this careful consideration will be taken to ensure there will be structures created

to ensure a wake for pedestrians as they flow around circulation paths.

To ensure the design optimises the utilisation of wind in a favourable manner the site will be

replicated using CFD software at an early stage and geo-located to ensure accurate portrayal

of the wind conditions upon completing of this. Options will be devised to evaluate the best

concept for creating natural ventilation and comfortable movement are the building. The

use of this software opposed to the wind tunnel alternative will allow more options to be

tested in a quicker and cheaper way.

The use of geo-located solar studies for solar utilisation:

Although the study of solar behaviour and utilisation on a site are often evaluated in

projects it is often not effectively implemented as designers base their ideas on ‘rule of

thumb’ theories. In previous schemes it has been known for a design to focus on utilising

the south orientation without consideration of heat loss creating walls that lose more heat

than create.

During the design of the concept aspects like these will be considered to ensure they are

avoided, instead the building will consist of an a array of various windows, both high and

low level, that will utilise the gains created on the fascia whilst maintaining a comfort level

within the structure. These windows will be coordinated with the ventilation stacks to

32

ensure that during both the winter and summer a comfort level is maintained that does not

require extensive mechanical assistance.

The use of a digital simulation to evaluate the effect of the sun on various designs will allow

a year round simulation to be achieved in a more realistic timeframe. In addition to this,

unlike the use of a Heliodon different conditions can be replicated that could occur such as

overcasting. By using this method the location of the windows can be defined based on how

the model reacts.

33

BIBLIOGRAPHY

Athienitis, A.S., M (1986) Thermal Analysis and Design of Passive Solar Buildings . 1st ed.

London: James & James.

Blackmore, P.A. (1997) Proceedings of the ICE - Structures and Buildings-The role of wind

tunnel testing in the design of building structures . 122(3) , pp. Dec 2014.

BRE (2006) Designing Quality Buildings . 1st ed. Watford: IHS BRE Press.

Business Innovation & Skills. . Government Construction Strategy. (2011) London:Cabinet

Office.

Canadian Architect Enclosure Design Tools-Analog Design ToolsAvailable at:

<http://www.canadianarchitect.com/asf/enclosure_design_tools/analog_tools/analog_to

ols.htm>.

Cengiz, C. (2013) The Flow of Air in an Urban Area . [online] .

Cheung, K.P, Chung, S.L (2002) International Journal on Architectural Science- A Table

Top Heliodon With A Moving Light Source for use in a Architects Office. , 3(2), pp. 51-60 .

Demetriou,P. (n.d) Simulation Software: A Tool for Passive Solar Design , n.d.

Englebart, D. (1962) Augmenting Human Intellect, .

Glodon, Glodon BIM Overview . [online] .

Haberl, J.C., S (2004) Literature Review of Uncertainty of Analysis Methods Texas Engineering

Experiment Station, Texas A&M University.

34

Hawkes, D. (1996) The Environmental Tradition-Studies in the Architecture of Environment . 1st ed.

London: E & FN Spon.

Heesom,D. Emerging Technologies BIM. 6AT016. Emerging Technology. October 2014,

University of Wolvehampton .

Hegedus, K. (2012) [online] .

HM Government. . Construction 2025. (2013) London:HM Government.

Hovart, M.W., M (2012) Solar Design of Buildings for Architects: Review of Solar Design Tools ,

T.41.B.3. SHC.

HPD, (2008) An Example of a Typical Heliodon . [online] .

Jankovic, L. (2012) Designing Zero Carbon Buildings-Using Dynamic Simulation Methods . 1st ed.

Oxon: Routledge.

Krygiel, E, Nies, B (2008) Green BIM­Successful Sustainable Design With Building

Information Modelling . 2nd ed. Canada: Wiley.

Lawson, T. (2001) Building Aerodynamics . 1st ed. London: Imperial College Press.

McGee, C. (2013) Your Home-Passive Design Australian Government.

National Intrsuments, An Example of a Wind Tunnel Used for Chifley Square, Australia . [online]

.

Osser, R. (2007) Development of two heliodon systems at MIT and recommendations for their use.

Unpublished MSC., MIT-Department of Architecture.

35

Perlin,J. (2013) Let It Shine: Solar Design in Ancient Greece

. Mother Earth News. Available at <http://www.motherearthnews.com/renewable-

energy/solar-design-in-ancient-greece-zbcz1312.aspx#axzz3NlZ1xRkj>.

Quirk, V. Quirk, Vanessa. "A Brief History of BIM / Michael S. Bergin" 07 Dec 2012. ArchDaily.

Accessed 15 Dec 2014. <http://www.archdaily.com/?p=302490>.

Scanlan, R.H. (1978) Wind Effects on Structures-An Introduction to Wind Engineering . 1st ed. John

Wiley & Sons.

SHC, (2012) An Example of a Geo-Located Solar Study Analysing Solar Radiation, Shadowing and

Exposure . [online] .

Systems Sites Buildings, (2011) An Example of a Solar Path Diagram Representing the Sun Path

over a 6 Month Period . [online] .

Szokolay, S. (2003) Introduction to Architectural Science-The Basis of Sustainable Design . 3rd ed.

Oxon: Routledge.

Tu, J., et.al (2012) Computational Fluid Dynamics . 2nd ed. Oxford: Elsevier.

TVT, (2015) An Example of a Vector Plot Representing a Turbulent Flow around a Sphere . [online] .

UCLA, (2007) An Example of a X-Y Plot Presenting the Temperature in Comparative to Wind Speed .

[online] .

Yeom, J. and Han, K. (2010) Improved estimation of surface solar insolation using a neural

network and MTSAT-1R data. Computers & Geosciences [online], 36(5), pp. 590-597 Available

36

at:<http://www.sciencedirect.com.ezproxy.wlv.ac.uk/science/article/pii/S00983004100005

67>.

Yeom, J. and Han, K. (2010) Improved estimation of surface solar insolation using a neural

network and MTSAT-1R data. Computers & Geosciences [online], 36(5), pp. 590-597 Available

at:<http://www.sciencedirect.com.ezproxy.wlv.ac.uk/science/article/pii/S00983004100005

67>.

37

APPENDIX A

33

A History of Building Energy Modelling (Haberl, J. Cho, S. 2004)