Checklist for Energy Simulation Input Data
How to use this checklist
This checklist serves as a reference guide and cookbook for collecting input data required for an energy
simulation of a generic building. It is aimed at a broad range of users and thusly requires no previous
experience or background in energy simulations.
The document is divided into three chapters: Checklist, Glossary, and Appendix. The checklist chapter
is sectioned into functional groups such as building structure, building envelope, building systems,
etc… However the checklist is NOT intended to be completed sequentially, on the contrary if for any
lack of data or if inapplicable, the user is recommended to proceed with other entries in the checklist.
Throughout the checklist the user will find boldfaced keywords. This indicates that an explanation and
a short description of the highlighted keyword is provided in the Glossary chapter. Moreover the short
description in the Glossary chapter might often contain a reference to one of the appendices. In the
Appendix chapter the user will stumble upon visual and graphical aid such as schematic examples,
charts, and drawings to help describe the specified requirement.
Map key:
1
BOLD ->
lookup in Glossary chapter
*
highly recommended but optional
->
Checklist
Assignment
Building Plans
Layout drawings
Section drawings
Façade drawings
*IFC files
Site Specification
Geographic Location
Shading and other peripheral objects
Topographical data
Building Envelope
External walls
Internal walls
Insulation
Roof
Underground / basement walls
Concrete Slabs
Description of Thermal Bridges
Infiltration data
Glazing
Detailed window and frame drawings
Glazing Specifications
Inner and outer curtain/blind specifications,
control set points, and operating schedule
Heating and Cooling Systems Type of central heating source
Return and Supply temperatures
Description of subunits, storage tanks, and
distribution system
Specification and set points for room heating
units
Specific Fan Power and Pump rating, *flow,
and efficiency
Operating schedule
Description of storage and pipe insulation
Installation capacity
Description and
Specification of Cooling
Systems
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Type of central cooling source
Return and Supply temperatures
Description of subunits, and distribution
system
Specification and set points of room cooling
units
Specific Fan Power and chiller/cooling tower
rating, *flow, and efficiency
Operating schedule
Description of storage and pipe insulation
Installation capacity
Design Schema
3
Ventilation System
Number and type of air handling units
Specific Fan Power and total air flow
Specification and efficiency of heat recovery
unit
Specification of Humidifier/Dehumidifier
unit
Air supply controller and set points
Fan Operating schedule
Number and Specification of exhaust fans
Design Schema
Zoning
Functional description of each HVAC zone
Occupant Capacity and Presence Schedule
Electronic equipment power rating
Illuminance Level
Building Facilities
Electrical rating and operating schedule for
elevators, external lighting, and other
installations
Installed capacity and control type of surface
heaters and drain heaters
Specification and efficiency of miscellaneous
compressors, pumps, fans, and storage tanks
Glossary
Air Supply Controller ...................................... 3
The supply of air into each room can be
controlled by different sensors that regularize
the flow. A common controller is the CO2
sensor, which can indicate the level of
occupancy present in a room and adjust the
flow rate accordingly. However the AHU can
also be controlled via a Passive InfraRed (PIR)
sensor, or by means of a Volatile Organic
Compounds (VOC) sensor, or simply through a
predetermined fixed schedule, etc… Therefore
it is important to specify the type of air supply
controller used in each room. Tip: This can be
done by manual inspection, through the
Building Management System, or by referring
to the ventilation schematics! See Appendix A
for a visual aid as to how to identify each
sensor by inspection.
Central Heating/Cooling Source ................ 2, 3
Each building has a central heating and cooling
supply source, but those differ from one
building to another. For instance a common
type of heating and cooling source in Sweden
is District cooling and District Heating, which
supplies hot and cold water directly to the
building from a nearby thermal plant or
substation. Another common type of central
cooling and heating system found in
standalone houses are boilers and chillers.
Each system behaves differently and has
different efficiency and capacitive rating.
Hence it is vital to accurately report on the type
of central heating and cooling system located
in the building.
Chiller/Cooling Tower .................................... 3
A chiller is a machine that makes use of
refrigerants to lower the environment
temperature through vapour-compression or
absorption cycles. Chillers can be very complex
and include multiple secondary cycles,
however we are mostly interested in the
overall rated power and the Coefficient of
Performance (COP) of the whole system. You
can locate this easily on the metal plated tag
placed on the chiller through manual
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inspection, or by looking up the technical
specifications directly from the manufacturer,
you can also attain a general idea concerning
the chiller performance by inspecting the
cooling schematics if they exist.
A cooling tower on the other hand resembles
essentially an evaporator, where water is
circulated with an overhead fan to cool the
water temperature to "near wet-bulb" through
evaporation. Similarly for our interest we
require only the Specific Fan Power and the
Coefficient of Performance (COP), which again
can be looked up in the technical specifications
provided by the supplier/manufacturer.
Control Type ................................................... 4
There are several types of controllers which
might be incorporated in a building. The most
common of which is a PI, or Partial Integrator
controller, and the bang-bang controller (also
known as the simple on/off controller). These
controllers dictate how the system behaves
once the sensor detects an event. For instance
a PI controller will insure a smooth startup and
shutdown period, whilst an on/off controller
will insure instant reaction time with several
fluctuations. Note that usually controllers have
a dead band limit, especially in the case of a
bang-bang controller, to limit the flunctuations
and avoid breakdowns.
Curtain/Blind .................................................. 2
Curtains and blinds play a vital role in blocking
solar radiation, preventing them from entering
rooms and causing discomfort or unwanted
heating loads. They can be placed internally,
externally, or even on both sides of a window.
Moreover these can be controlled either
manually, or automatically based on room
temperature, outdoor luminance, or by a
predetermined fixed schedule.
Design Schema ............................................... 3
Schematic designs are drawings provided by
consultants, manufacturers, designers, or
suppliers detailing in technical terms the
system at hand. Refer to Appendix B for a
sample schematics
Dimensioning .................................................. 2
Knowing the material thickness and area is
important for evaluating the heat transfer
through walls and surfaces. As such it is simply
not enough to specify the materials being used
in the building envelope, but the dimensions of
each layer is as important for simulation
purposes.
Drain Heaters.................................................. 4
In most Northern countries, drain heaters are
installed to prevent drain blockage in case of
ice forming in winter. This can utilize
substantial thermal energy that need be
accounted for in your simulation.
Efficiency......................................................... 3
Efficiency is evaluated as useful work output
divided by input power. This holds true for
electrical and mechanical systems, and implies
that the more efficient the system is the more
useful work you attain for a given amount of
input power. For thermal systems this term is
often replaced by Coefficient of Performance
which indicates not only the efficiency but also
provides insight on the operating conditions.
COP is evaluated as heating power supplied
divided by the work consumed. Both efficiency
and COP values can be found through the
technical
specifications
provided
by
supplier/manufacturer, or simply by manual
inspection of the metal plated tag on the
machinery.
Electronic Equipment ..................................... 3
The term electronic equipment includes all
devices plugged in a room, such as computers
and screens, projectors and routers, heavy
machinery, phones and personal devices, etc…
Tip you can use default values of electronic
equipment to estimate the overall power
rating per room!
Exhaust Fans ................................................... 3
The number of exhaust fans may not be
equivalent to the number of supply fans, even
though the ventilation system is designed to be
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balanced. This implies that we need to provide
the specifications of each exhaust fan along
with each supply fan specification. This
specification often includes Specific Fan Power
and operational schedule
Façade............................................................. 2
The building Façade describes the building's
exterior. This usually includes glazing,
balconies, decorative structures, and envelope
material. It is important for us to know the
orientation of each façade of the building, as
this plays a major role in infiltration,
ventilation, and heating requirements of the
building. Façade drawings are usually provided
by architects and consulting firms.
Flow ................................................................ 3
Volumetric flow may refer to air flow or liquid
flow rates. It is often very difficult to measure
these in building systems, as they require non
intrusive methods such as ultrasonic and
magnetic flow measurements in case of fluid
flow, which can be quite expensive to deploy,
and airflow meters in the case of gas flow
measurements, which are often unreliable.
Frame .............................................................. 2
Window frame plays an important role in
determining heat dissipation as well as
infiltration rate. Since the frame material
differs from that of the glazing, it will have a
different heat transmission rate.
Functional Description ................................... 3
Describing the activity that takes place in each
zone is an important task. This dictates generic
schedules, ventilation and heating/cooling set
points, as well as number of occupants.
Geographic ..................................................... 2
The longitude and latitude of the building helps
determine the correct adjusted weather data
file to use as well as the wind profile. Note
Google maps is your friend!
Glazing ............................................................ 2
Glazing is an important aspect of the façade.
It's specifications and properties determines
how much solar energy is transmitted and
absorbed by the building. See Appendix C for
an example of glazing specifications and
properties.
Heat Recovery Unit ........................................ 3
Heat recovery unit in an air handling system
comes in many forms. It can be an exchange
thermal wheel where return air with higher
temperature is mixed with cool supply air, or it
can take the form of a non mixing heat
exchanger such as a run around coil system.
Humidifier Unit ............................................... 3
A humidifier is sometime necessary in an air
handling unit to bring the relative humidity of
the supply air to an appropriate level, avoiding
dry air or a very humid environment. However
the process of adding in or removing moisture
from the supply air requires cooling and/or
heating of the supply air. This can lead to
significant energy consumption, and as such
must be modeled properly in your simulation.
HVAC Zone ...................................................... 3
An HVAC zone can include several
geometrically connected rooms. It describes all
rooms which entail the same inlet supply air
from the ventilation system. For instance a
single HVAC zone in extreme cases can include
the whole house, as is the case when there is
but a single supply inlet.
IFC ................................................................... 2
IFC stands for Industry Foundation Classes, and
is a type of neutral file format that encumbers
descriptive information of each zone along
with its geometric data. This tuple of
information allows the energy simulator not
only to model the geometric zones, but also
setup the system set points, and other
information that can speed up modeling. Tip:
Most CAD software can export drawings in IFC
format!
Illuminance Level............................................ 3
Luminance inside each zone is vital in
modeling, as it needs to ascertain a
standardized level.
Infiltration....................................................... 2
Infiltration is often one of the most difficult to
measure. Some buildings undergo proper
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pressurized testing and therefore infiltration
data would be readily available, however a
common alternative is to inspect opening seals
using an air flow meter.
Installation Capacity ...................................... 3
Installation capacity is often the result of sizing
activities, as such it sets the limits of the
building's system that can be justifiably tested
in an energy simulation. For instance to find
whether a heating room unit is sufficient for
maintaining thermal comfort in a selected
room, installation capacity of the whole
system must first be made known.
Insulation ........................................................ 2
Insulation is perhaps one of the most
influencing factors in a building's energy
demand. Thus accurately determining the
thickness and material specifications of the
envelope, pipes, and storage tank insulation is
vital to any simulation.
Layout ............................................................. 2
Layout drawings facilitate the sectioning of
each zone in your model. These are often
available and supplied by the architects. Refer
to Appendix D for a sample of a Layout
drawing.
Materials ........................................................ 2
Building materials not only define the heat
transfer rate of the envelope, but also denotes
how the building reacts and transitions from
one state to another. It is vital to properly
capture the material properties and
dimensions used throughout the building.
Refer to Appendix E for a sample on how to
report on material specifications.
Occupant Capacity ......................................... 3
Occupants are a source of humidity, heat, as
well as CO2 emissions. Hence it is important to
determine the designed occupancy capacity of
each zone to properly size ventilation and
cooling/heating loads.
Operating Schedule .................................... 2, 3
Building systems can attain different operating
schedules, it is therefore important to note
each up-to-date system schedule. This can be
done by inspecting the control schematic,
through manual inspection, or by consulting
maintenance and operations.
Peripheral ....................................................... 2
Peripheral objects, those casting shadows on
the building, can contribute to solar shading,
wind blocking, as well as air preheating. Thus
do not forget to include close structures in the
vicinity of your building model.
Pipe Insulation ................................................ 3
Pipe heat losses can become a significant
factor in reducing energy consumption. You
can account for this in your model by going
through manual inspection of the current
status of piping insulation.
Presence Schedule.......................................... 3
Occupancy presence scheduling can have a
dramatic impact on energy loads of a building.
However it is often difficult to capture the
stochastic nature of this presence. In energy
simulations you are able to input probabilistic
curves as your best guestimates, or a
predetermined fixed schedule. Tip: It is
advisable to add holiday schedules separate
from weekdays, as these tend to be very
different!
Pump Rating ................................................... 3
Pump power and efficiency is often a key
parameter in the performance of a mechanical
system. This is often the case in buildings
where pumps are not properly sized, or
operating in suboptimal conditions. It is
therefore important to take note of the
current operating schedule of these pump, as
well as the performance criteria.
Return/Supply Temperature...................... 2, 3
The supply temperature and return
temperature can be utilized to determine
overall heat/cooling power delivered to the
building. It is often easy to access this
information through measurement or through
consulting your source supplier.
Room Heating Units ....................................... 3
Room heat units come in different types and
forms. They can work through radiative,
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convective, conductive, or combination of the
latter three. Each type has it's own efficiency
and heats the room in a different manner, thus
it is important to note not only the heating
power but also the type of heating supplied
into each room. Refer to Appendix G for visual
aid in determining types of room heating units.
Section ............................................................ 2
Section drawings reveal material layering as
well as joint and structural information useful
to us in the modeling phase. Refer to Appendix
D for a sample Section Drawing.
Set Point ..................................................... 2, 3
Set points for building systems and controls are
often manually configured but poorly
managed and updated throughout the life
cycle of the building. Nonetheless these set
points dictate the performance of nearly every
system, whether it be ventilation or
cooling/heating, and it is therefore crucial to
have accurate representations of these set
points in the simulation process.
Shading ........................................................... 2
Aside from blinds and curtains, some buildings
contain shading in the form of balcony fins and
awnings. These greatly reduce the solar load in
rooms and thusly needed to be considered in
an energy simulation. Refer to Appendix F for
a visual aid of typical types of awnings.
Slabs................................................................ 2
What is usual referred to as concrete slabs,
often play a dominant role in thermal bridges
and material properties. Moreover some
buildings integrate slabs in concrete as a
means of cooling. Refer to Appendix J for a
sample on how to calculate overall material
property with presence of concrete slabs.
Specific Fan Power ......................................... 3
Specific Fan Power is a term to quantify the
energy efficiency of a fan which is evaluated as
electrical power input in relation to the
volumetric air flow through the fan. This in turn
implies that SFP is not constant for any given
fan, but will vary in accordance to the pressure
difference and the across volumetric air flow.
Storage ........................................................ 2, 3
Storage thermal tanks are often used to
provide large buildings with instant hot water,
especially on peak demand. However if ill
maintained these storage tanks might become
a major leak source of energy, and as such
proper insulation, accurate predictive
operational scheduling, and reasonable set
points and capacity are vital for achieving
optimal energy performance.
Subunits ...................................................... 2, 3
In larger buildings it is often the case that
subunits are installed to reheat, store and/or
redistribute heating/cooling load onto each
room. In many such cases, these subunits
become bottlenecks in the building system as
it is tedious and costly to maintain each
subunit. Hence they might become a source of
large discrepancy between your modeled
simulation and reality. To properly account for
this factor you need to take into account the
current specifications and performance of
each subunit.
Surface Heaters .............................................. 4
Surface heaters are usually utilized to defrost
pavings and slopes as a safety requirement,
and as such are also a significant source of
energy consumption.
Thermal Bridges.............................................. 2
Thermal Bridges act as highways for thermal
transmittance from the building to the outside
environment. However it is quite difficult at
times to evaluate the effect of thermal bridges.
8
However section drawings and a few thumb
rules can help you guestimate this effect in
your model. Refer to Appendix J for a sample
on how to compute overall U-value of a
Thermal Bridge
Topographical................................................. 2
The geographical location of the building helps
reveal the topography of the surrounding area.
This is vital for an energy simulation as to
determine the proper elevation of peripheral
obstacles and shades. Tip: You can easily grab
a topographical map from Google maps using
longitude and latitude data of the building!
Type of AHU ................................................... 3
Air handling units are composed of several
subunit components and can come in many
number of combinations of the latter subunits.
For instance a typical AHU is often composed
of an inlet fan, heat recovery unit with/without
air mixing unit, heating/cooling coil,
De/humidifier, outlet vent, and finally an
exhaust fan and exhaust vent.
Underground/Basement ................................ 2
Underground/Basement refers to walls of the
building that are in contact with soil/ground
which often takes on a constant temperature
profile. Moreover these facilities often have
different heating/cooling and ventilation
requirements, which implies they ought to be
considered and reported separately from
other rooms and facilities.
Appendix A – Common Air Supply Controllers
CO2 sensor takes measurement of CO2 emissions in a room with units of
ppm (particle per million). Normal background level is around 250-400
ppm. CO2 levels >5,000 ppm indicate toxicity levels.
Figure 1. CO2 sensor
VOC sensor takes measurements of organic gas chemicals that
Have high vapour pressure at room temperature, such as paints/coatings,
benzene, and aromatic compounds. These measurements also attain
ppm units, with varying toxicity levels for each compound.
Figure 2. Volatile Organic
Compounds sensor
PIR (Passive InfraRed) sensors are used for presence monitoring. Their
output signal is often a binary 1/0 value taken at specific time intervals.
Figure 3. Passive InfraRed
sensor with 110 deg scope
A Thermostat sensor is often a simple bimetallic wire strip which can be
used not only as a controller but also as a set point for room
Heating/Cooling
Figure 4. Room Temperature
Thermostats
9
Appendix B – Schematics & Technical Drawings
Air Handling Unit schematic example:
Figure 5. Air Handling Unit Schema
From this sample you can see a typical Air Hanling Unit, where supply air is controlled via a damper
as seen here:
Figure 6. Damper and controller
Tip: the sensor reading ST21 can help conclude the airflow schedule on the supply side of this AHU.
While the signal to the controller STXX (following the dashed line, representing wired extension) is
connected to a main switsh:
Figure 7. on/off switch
10
Tip: The switch implies that we have a simple bang-bang or on/off controller for the AHU, it also
shows the signal leading to the DUC or PLC (Programmable Logic Controller) represented by the
letter I. signal I is connected in turn to a switch SO11, implying a schedule based controller for the
AHU fans.
After the damper we find a filter on the supply air, along with a manometer (pressure meter) as seen
here:
Figure 8. Air filter and manometer
The filter causes a pressure drop in the ventilation duct, where further down the line the supply air is
mixed and preheated in the heat exchanger seen here:
Figure 9. Economizer with controlled flow dampers and temperature sensor
The heat exchange and mixing is controlled via the two latter dampers on the supply side through
the STXXX controller.
After which the supply air is further heated by a hot water heat exchanger seen here:
11
Figure 10. Pre-heater water to air
This causes the supply air to release its moisture content and as a result have a lower relative humidity,
as well as heats the cold air to the required set point temperature if necessary. Furthermore a cooling
exchanger via cold water is placed afterwards in order to regulate the air supply temperature, seen
here:
Figure 11. Pre-cooler water to air
Finally on the supply side we find a centrifugal fan with a three stage switch and a fuse box, fired up
by a switch along the same line as the primary switch for the AHU, as seen here:
Figure 12. Centrifugal fan with a three way switch and fuse box
Tip: The three stage switch on the centrifugal fan implies that the air supply controller is a step
controller and is thusly a CAV system (Constant Air Volume).
We also find a temperature air supply sensor as well as a smoke detector (in the case of fire) down
the line, represented here as:
12
Figure 13. Temperature and smoke detection sensor
Tip: The sensor measurements from GT11 is the actual air supply temperature to the room! Also GT11
regulates the heat recovery, heating, and cooling of the supply air via DUC signal RI shown above.
The same configuration is also seen in the air return line with an exhaust fan at the end of the line
represented by FFXX.
In summary the typical required information to input in your simulation in this example is the position
of the dampers with respect to time, the type of economizer (heat exchanger) in the heat recovery
unit as well as its efficiency, the percent of air mixing and recirculation, the set point temperatures
and capacity of the pre-heater and pre-cooler units (including defrosting settings), the set point
temperature of the air supply sensor (for both night set point and maximum set point), the fans’
operation schedules and controller type and specifications (VAV or CAV), and finally power
consumption and return temperature.
13
Central heating system schematics, an example:
14
Figure 14. Central Heating System consisting of a primary base load gas boiler circuit and a secondary peak load solar thermal circuit.
The schematic reveals two gas boilers in series, connected to a heat storage tank in a closed loop. The
flow is driven by two parallel pumps and managed by a separate controller. Furthermore the closed
loop has an expansion valve to ensure pressure release in case of high pressure build up along with an
air separator.
Moreover there is a secondary renewable heating system plugged to the same heat storage tank. The
closed solar heating system is managed by a separate controller and has two circulations (one flow to
the solar collectors, and another flow towards the storage tank). There is a cross-flow heat exchanger
to deliver the heat from the working media to the water in the heat storage tank, along with another
expansion tank to ensure safe pressure requirements in the closed circulation loop.
On the distribution side, we have two parallel pumps utilized to ensure high volume flow at a constant
pressure head for the building. While the storage tank itself is regulated via a water thermostat as
seen above.
To model this in your simulation you will have to report on the following parameters: set points of the
gas boilers along with performance criteria and efficiencies, the operating schedules of the pumps in
each of the two heat systems, the controller type and set points of each heating system, a description
on the piping and storage tank insulation, and the water thermostat set point and controller type
along with the thermal efficiency of the tank itself (noting down the supply and return temperatures
on the storage tank), the type and specifications of the solar collectors (see Appendix C for Glazing
properties).
Tip: Refer to the Control & Instrumentation schematics for a proper representation of scheduling and
control type. The control schema usually contains a narrative describing the controller actions, for
instance in the latter example we have from the control schematics the following description:
Figure 15. Control Schematics narration
15
Appendix C – Glazing & Frames
When reporting on glazing properties and specifications we need to know the following:
Figure 16. Solar radiation distribution across glazing
This diagram shows the total Incident radiation received at the outer surface of the glazing, this data
is not required to be reported upon, instead it is simulated in the model. However to realize the
properties of the glazing itself, you need to report of the Solar Reflectance (SR), Solar Absorbance, and
Solar Transmission (ST). Alternatively you can report on the total Solar Shading Coefficient (g) along
with one of the latter three parameters. Note that this is usually done for both light spectrums (the
near infrared “NIR” and the visible), since those two spectrums constitute an accumulative 95% of all
energy in the incident radiation. Below is an example of this:
Table 1. Glazing properties and specifications
This shows the product configuration, for instance (6X-16Ar-Y4) implying a 6mm of glazing type X along
with a 16 mm Argon gap and a 4 mm glazing type Y. Common configuration can be seen below, along
with the frame structure:
16
Figure 17. Glazing configuration along with frame
The figure shows from left to right: the two single, one double, one single and one double, one double
and one single, one tripple glazing configuration respectively. More over each single glazing can have
a low-e (low emmissivity coating) on either side (inner/outer).
Furthermore the type of configuration is displayed in the second column in order to separate between
for example a two single glazing configuration and a one double glazing configuration. Furthermore
the total U-value of the overall configuration is given in the third column, along with the total Light
Transmittance (Solar Transmittance in visible spectrum as a percentage value) and the Solar Shading
Coefficient. This information should be enough for our modeling purposes, however if a more detailed
glazing model is required, one can utilize each singleton U-value, Light transmittance, Light
Reflectance (Solar reflectance in visible spectrum), R index (fraction index going from air into glazing),
Solar Transmittance, and glazing density given in the table above.
It is important to note here that the overall U-value of the configuration does NOT include that of the
frame. The frame attains a separate heat transmittance property, and can act as a thermal bridge (see
Appendix K). Therefore don’t forget to report also on the frame material properties.
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Appendix D – Layout & Section Drawings
Section and Layout drawings contain valuable information that need to be obtained for simulation
modelling, however they come in many forms. Below is an example of a section drawing of an
apartment’s wall.
Figure 18. Wall section drawing
This shows the materials including insulation between the inner and outer walls. Moreover we can
see the material dimensioning through all neighbouring walls, floors, and the roof. Note that a
section drawing can also include the whole building such as the figure presented below:
Figure 19. Section drawing of an apartment
In this section drawing we are interested in the wall separation throughout the apartment and the
dimensioning of the apartment façade.
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Furthermore section drawings of whole buildings can also be used to superimpose other relevant
information such as air flow diagrams similar to the figure below:
Figure 20. Air flow diagram with HVAC Zones
Note that this section air flow diagram contains no material information, but it reveals HVAC zoning
details as well as inlet air distribution (denoted by left hand values: XX / ) and exhaust air outlets
(denoted by right hand values: / XX or sometimes by negative numbers). You can also visualize the
different box compartments of the Air Handling Units and distribution network.
Layout drawings on the other hand not only contain important geometric zoning and dimensioning
information, but can also reveal other data required for simulation such as in the site layout drawing
below:
Figure 21. Site layout drawing
19
Notice here that we can deduce the orientation of the building itself, due to the inclusion of a
reference North orientation in the lower right corner of the graph. Furthermore peripheral buildings
and shadings are also clearly visible in this layout.
20
Appendix E – Materials
Of the many properties a material attains and might be used to describe it with, for our simulation
purposes we are interested mainly in physical, thermal, and optical properties of the material at hand.
Hence when reporting on non-glazed building materials be sure to include the following (for glazed
materials refer to Appendix C):
Density (), thermal conductivity (k), emissivity (ɛ), physical dimensions (LxWxH), and specific heat
capacity (Cp). More often these latter parameters are enough to accurately portray the building
material in an energy simulation.
For windows and other glazed surfaces please refer to Appendix C on how to report their specifications
and properties.
Density,  (kg/m3)
2240 - 2400
21
Thermal conductivity,
k (W/mK)
0.3
Emissivity, ɛ (-)
0.85
Dimensions
(m.m.m)
X.Y.Z
Specific heat (KJ/Kg.K)
0.75
Appendix G – Room Heating Units
Heating elements in rooms rely on different physical phenomena to deliver their heat into the room.
One such method of heat transportation is through convection. A room convector heats up the air
around it, and relies on the rising advection of air to transport heat to other parts of the room. To
capitalize on advection, convectors are commonly placed low to ground level and under openings and
glazings.
Figure 22. A common type of convector
Figure 23. Common type of convector
Figure 24. Floor heating diagram, also relies on convection
Another type of heating element found in rooms is the radiator. A radiator relies, as its name suggests,
on thermal radiative energy to transport its heat to the surrounding environment. This implies that a
radiator transfers heat through electromagnetic waves throughout the room, as a result the thermal
radiative energy transfer is highly dependent on the temperature difference between the radiator
surface and the surrounding room, as well as on the viewing factor between the radiator and the
person in the room. Due to this, the radiator often is used for local targeted heating as opposed to
whole room heating.
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Figure 25. Infrared room unit heater
To model any of the latter units in a simulation, you will need to specify the main heat transfer mode
(convection or radiative), as well as the maximum capacity given in Watts and the set point
temperature of the device. Note: Even convectors, as those mentioned above, do in fact transmit
some of their heat through thermal radiation and conduction, however what is of interest is the
dominant mode of heat transfer in this classification process.
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Appendix H – Awnings
Awnings play a vital role in building shading and reducing solar loads in rooms at peak hours. It is
simple enough to note down the geometric configuration of the available awnings for modelling
purposes. Awning material and such can usually be neglected for simulation modelling purposes.
Figure 26. Common awnings types
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Appendix I – U-values & Slabs
Concrete slabs are very commonly used in any modern type construction, and often contain metal
rebars (for reinforcement and added flexibility) as well as metal T-bars and at times cooling coils, as
seen in the below section drawing:
Figure 27. Section drawing of a floor joint showing slabs & rebars
These additional materials have an important effect on a building’s energy performance, as is the case
with a thermal bridge (see Appendix K) and the case of reinforced concrete. Hence it is vital to report
on the type of concrete and its respective U-value.
U-value (Overall Heat Transfer Coefficient) of a material is defined as the inverse of the thermal
resistance of any given material (R), which in turn is given as the material length with respect to its
thermal conductivity (L/k).
Therefore, for instance the thermal conductivity of Portland cement (common concrete) is around
0.3 W/m.K, as such a 10 cm thick block of concrete has a thermal resistance of 0.010/0.3 = 0.033
m2.K/W and thusly has an overall heat transfer coefficient U = 30 W/m2K.
If several layers with different contact areas exist in a single configuration, you can use the following
to estimate the U-value of the whole material:
1 / UA = 1 / (1/A1h1 + dx/kA + 1/A2h2)
Where h is the thermal conductivity of each of the surrounding fluid media, k is the thermal
conductivity of the material itself and dx is the thickness of given material, while A1 and A2 represent
the surface contact area between the material and the fluid media surrounding it
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Appendix J – Thermal Bridges
Thermal bridges are often a major source of energy leaks in buildings, and as such should be properly
accounted in your simulation model. The reasoning behind this is simply due to the nature of a thermal
bridge acting as a highway for thermal heat transfer between the warmer building interior and the
colder exterior environment, as seen below:
Figure 28. Section diagram of a thermal bridge
To model this effect one needs to properly evaluate and detect thermal bridges in a building, and this
remains a major challenge. Thermal bridges need to be inspected by going through the section
drawings and focusing on joints, intersections, balconies, and any other type of connections that are
not well insulated and can act as a link to the outside environment.
Once a thermal bridge is identified, you need to indicate its linear thermal conductivity () or its point
thermal conductivity () depending on the geometric configuration of the thermal bridge, as shown
below:
Figure 29. Diagram showing the Heat transfer coefficient of the structure consisting of two line thermal bridges, and a single
point thermal bridge.
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For the example given above, to properly evaluate the overall heat transfer coefficient one needs to
know the line thermal conductivity 1 and 2 as well as the point thermal conductivity value 1.
Afterwards by simply adding U1A1 with 1L1, 2L2, and 1, you will obtain the heat transfer coefficient
of the wall, balcony, window, and door configuration.
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