ISO/TR 52120-2:2021

Energy performance of buildings — Contribution of building automation, controls and building management — Part 2: Explanation and justification of ISO 52120-1

This document contains information to support the correct understanding, use and adoption of ISO 52120‑1.

Performance énergétique des bâtiments — Impact de l’automatisation, de la régulation et de la gestion technique des bâtiments — Partie 2: Explication et justification de l'ISO 52120-1

General Information

• Status: Published
• Publication Date: 15-Dec-2021
• ICS: 91.120.10 - Thermal insulation of buildings
• Technical Committee: ISO/TC 205 - Building environment design
• Drafting Committee: ISO/TC 205/WG 3 - Building Automation and Control System (BACS) Design
• Current Stage: 6060 - International Standard published
• Start Date: 16-Dec-2021
• Completion Date: 16-Dec-2021

Relations

• Consolidates: ISO 247-1:2018 - Rubber — Determination of ash — Part 1: Combustion method
• Effective Date: 06-Jun-2022

Standards Content (Sample)

TECHNICAL ISO/TR
REPORT 52120-2
First edition
Energy performance of buildings —
Contribution of building automation,
controls and building management —
Part 2:
Explanation and justification of ISO
52120-1
PROOF/ÉPREUVE
Reference number
ISO/TR 52120-2:2020(E)
©
ISO 2020

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ISO/TR 52120-2:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
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Published in Switzerland
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ISO/TR 52120-2:2020(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 1
4.1 Symbols . 1
4.2 Abbreviated terms . 1
5 Method description . 2
5.1 Effect of building automation and control (BAC) and technical building
management (TBM) . 2
5.1.1 General. 2
5.1.2 Control accuracy. 2
5.1.3 Control function . 3
5.1.4 Control strategy . 4
5.2 Description of BAC functions . 5
5.2.1 General. 5
5.2.2 Heating control . 5
5.2.3 Domestic Hot Water supply control .10
5.2.4 Cooling control .12
5.2.5 Ventilation and air conditioning control .17
5.2.6 Lighting control .22
5.2.7 Blind control .24
5.3 Method 1 - Impact of BAC and TBM on the energy performance of buildings
(detailed method) . .24
5.3.1 Rationale .24
5.3.2 Time steps.24
5.3.3 Assumptions .25
5.3.4 Data input .25
5.3.5 Simplified input .25
5.3.6 Calculation information .25
5.4 Method 2 – Impact of BAC and TBM on the energy performance of buildings (BACS
factor method) .39
5.4.1 Rationale .39
5.4.2 Time steps.39
5.4.3 Calculation information .39
6 Method selection .40
7 Worked out examples .41
8 Information on the accompanying spreadsheet .42
Bibliography .43
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ISO/TR 52120-2:2020(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 205, Building environment design, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC
247, Building Automation, Controls and Building Management, in accordance with the Agreement on
technical cooperation between ISO and CEN (Vienna Agreement).
A list of all parts in the ISO 52120 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO/TR 52120-2:2020(E)

Introduction
The CENSE project, the discussions between CEN and the concerted action highlighted the high
page count of the entire package due to a lot of “textbook” information. This resulted in flooding and
confusing the normative text.
A huge amount of informative contents should indeed be recorded and available for users to properly
understand, apply and nationally adapt the EPB standards
The detailed technical rules in CEN/TS 16629 ask for a clear separation between normative and
informative contents:
— to avoid flooding and confusing the actual normative part with informative content;
— to reduce the page count of the actual standard;
— to facilitate understanding of the package.
Therefore, each EPB standard should be accompanied by an informative technical report, like this one,
where all informative contents is collected. See Table 1.
Table 1 — Position of this standard within the EPB set of standards
Over- Building Technical Building System
arching (as such)
Building
Domes- PV,
Submod- Descrip- Descrip- Descrip- Heat- Cool- Ventila- Humidifi- Dehumidifi- Light- automa-
tic Hot wind,
ule tions tions tions ing ing tion cation cation ing tion and
waters .
control
sub1 M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11
1 General General General
Common
terms and
defini- Building
2 tions; Energy Needs
symbols, Needs
units and
subscripts
(Free)
Indoor
Maximum
Applica- Condi-
3 Load and
tion tions
Power
without
Systems
Ways to Ways to Ways to
Express Express Express
4 Energy Energy Energy    x
Perfor- Perfor- Perfor-
mance mance mance
Building
Func- Heat
Emission
tions and Transfer
5 and con-    x
Building by Trans-
trol
Bounda- mission
ries
Building Heat
Occupan- Transfer
Distribu-
cy and by Infil-
6 tion and    x
Operating tration
control
Condi- and Ven-
tions tilation
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ISO/TR 52120-2:2020(E)

Table 1 (continued)
Over- Building Technical Building System
arching (as such)
Building
Domes- PV,
Submod- Descrip- Descrip- Descrip- Heat- Cool- Ventila- Humidifi- Dehumidifi- Light- automa-
tic Hot wind,
ule tions tions tions ing ing tion cation cation ing tion and
waters .
control
sub1 M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11
Aggre-
gation of
Energy Storage
Internal
7 Servic- and con-    x
Heat Gains
es and trol
Energy
Carriers
Building Genera-
Solar Heat
8 Partition- tion and    x
Gains
ing control
Load
Calculat- Building
dispatch-
ed Energy Dynamics
9 ing and    x
Perfor- (thermal
operating
mance mass)
conditions
Measured Measured Measured
Energy Energy Energy
10    x
Perfor- Perfor- Perfor-
mance mance mance
11 Inspection Inspection Inspection
Ways to
Express
12 BMS
Indoor
Comfort
External
Environ-
13
ment Con-
ditions
Economic
14 Calcula-
tion
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TECHNICAL REPORT ISO/TR 52120-2:2020(E)
Energy performance of buildings — Contribution of
building automation, controls and building management —
Part 2:
Explanation and justification of ISO 52120-1
1 Scope
This document contains information to support the correct understanding, use and adoption of
1)
ISO 52120-1 .
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 52120-1, Energy Performance of Buildings — Contribution of Building Automation, Controls and
Building Management — Part 1: Modules M10-4,5,6,7,8,9,10
EN ISO 7345, Thermal insulation — Physical quantities and definitions (ISO 7345:1987)
EN ISO 52000-1, Energy performance of buildings — Overarching EPB assessment — Part 1: General
framework and procedures
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7345, ISO 52000-1 and
ISO 52120-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Symbols and abbreviated terms
4.1 Symbols
For the purposes of this document, the symbols given in ISO 52000-1, in ISO 52120-1 apply.
4.2 Abbreviated terms
For the purposes of this document, the abbreviations in ISO 52120-1 apply.
1) Under preparation. Stage at the time of publication: ISO/DIS 52120-1:2020.
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5 Method description
5.1 Effect of building automation and control (BAC) and technical building
management (TBM)
5.1.1 General
The key-role of building automation and control and TBM is to ensure the balance between the desired
human comfort, which should be maximal, and energy used to obtain this goal, which should be
minimal.
The scope of BAC and TBM covers in accordance with their role from one side all technical building
systems (where the effect of the BAC is used in the calculation procedures) and from another side the
global optimization energy performance of a building.
We could identify several categories of controls:
— Technical building systems specific controls: these controllers are dedicated to the physical chain of
transformation of the energy, from generation to storage, distribution and emission. We find them
in the matrix starting with the Modules M3-5 to M9-5 and finishing with M3-8 till M9-8. We could
consider that one controller exists by module, but sometimes one controller does the control among
several modules. More often, these controllers are communicating between them via a standardized
open bus, such as BACnet, KNX or LON.
— BAC used for all or several technical building systems that do multidiscipline (heating, cooling,
ventilation, DHW, lighting) optimization and complex control functions. For example, one of them is
INTERLOCK, a control function that avoids heating and cooling at the same time.
— If all technical building systems are used in the building, we have (depending of the size of the
building) a technical building management system. Specific global functions are implemented here
and are necessary to reach the key-role mentioned above. Usually, in this case, an interrelation with
the building as such (Module M2) will occur, mainly to take in consideration the building needs;
for example, due to outside temperature, taking into account the inertia of the building when the
control will reach the set point in a room.
In a control system dedicated to a building, in this case BAC and TBM, we can distinguish three main
characteristics as described in 5.1.2, 5.1.3 and 5.1.4.
5.1.2 Control accuracy
Control accuracy is the degree of correspondence between the ultimately controlled variable and the
ideal value in a feedback control system. The controlled variable could be any physical variable such
as a temperature, humidity, pressure, etc. The ideal value is in fact the setpoint established by the user
(occupant) when he determines his level of comfort. It is clear that the entire control loop is concerned
with all the elements constituent, such as sensors, valves and actuators. The equipment itself is another
important element and usually specific equipment asks for a specific controller. For the energy carrier
hot water, an important issue is the balancing of the hydraulic circuits. For that purposes, balancing
hydraulic valves are need it.
The temperature control accuracy (CA) for a zone temperature is a key number that allows calculating
the additional energy needed for heating or cooling caused by the inaccuracy of zone temperature
control. The temperature control accuracy (CA) can be calculated from control variation (CV) and
control set point deviation (CSD) as described in the main text of EN 15500-1:2017. The compliance
with CA is also defined in EN 15500-1. This is an important input for EN 15316-2 and for EN 16798-7,
where the effect of the control for heating, cooling and ventilation is taken into account.
The same standard (EN 15500-1:2017) describes also the four operations modes that deal with the
levels of temperatures: comfort, pre-comfort, economy and frost/building protection. These four
predefined operation modes are parameters that could be set by the users (occupant) (e.g. the
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temperature allocated to each operation mode). These operations modes are important for the control
strategy used for intermittence, which will be described below.
5.1.3 Control function
The control function is the ability of a controller (or set of communicative controllers) to perform a
determined task(s). Usually the functions implemented in the controllers are parametric or freely
programmable. The functions could be performed by a single controller or by a set of communicative
controllers. A controller could perform several functions.
The control functions present in a BAC or TBM, are present in ISO 52120-1:—, Table 4. These functions
are organized in the matrix given by the modular structure of EPB standards. ISO 52120-1:—, Table 4
starts with heating emission, distribution, storage and generation (M3-5, M3-6, M3-7, M3-8) followed
by domestic hot water, cooling, ventilation and lighting (M9-5, M9-6, M9-7, M9-8). Each function
is described in detail, in accordance with the type (level) of the function: from the lower type (NO
AUTOMATIC CONTROL Type = 0) to most advanced types. For each function, an identifier that is the
software language for BAC and TBM is also defined, as the destination of the module where the control
function has its effect. An abstract from ISO 52120-1:—, Table 4 is given below as an example.
For practical reasons, four different BAC efficiency classes (A, B, C, D) of functions are defined both for
non-residential and residential buildings. This is the fastest way to specify a BAC or a TBM.
— Class D corresponds to non-energy efficient BAC. Building with such systems should be retrofitted.
New buildings should not be built with such systems.
— Class C corresponds to standard BAC.
— Class B corresponds to advanced BAC and some specific TBM functions.
— Class A corresponds to high-energy performance BAC and TBM.
A building is in class D: If the minimum functions to be in class C are not implemented.
To be in class C: Minimum functions defined in ISO 52120-1:—,Table B.1 are implemented.
To be in class B: Building automation function plus some specific functions defined in ISO 52120-1:—,
Table 4 are implemented in addition to class C. Room controllers are able to communicate with a
building automation system.
To be in class A: Technical building management function plus some specific functions defined in
ISO 52120-1:—, Table 4 are implemented in addition to class B. Room controllers should be able for
demand controlled HVAC (e.g. adaptive set point based on sensing of occupancy, air quality, etc.)
including additional integrated functions for multi-discipline interrelationships between HVAC and
various building services (e.g. electricity, lighting, solar shading, etc.).
In addition, the hydraulic system is properly balanced.
The functions assignment to the BACS efficiency classes is listed in ISO 52120-1:—, Table 5.
BAC functions with the purpose to control or monitor a plant or part of a plant which is not installed in
the building do not have to be considered when determining the class even if they are shaded for that
class. For example, to be in class B for a building with no cooling system no individual room control
with communication is required for emission control of cooling systems.
If a specific function is required to be in a specific BAC efficiency class, it is not required that this
function is strictly required everywhere in the building: if the designer can give good reasons as to
why the application of a function does not bring a benefit in a specific case then it can be ignored.
For example, if the designer can show that the heating load of a set of rooms is only dependant on the
outdoor temperature and can be compensated with one central controller, no individual room control
by thermostatic valves or electronic controllers is required to be in class C.
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A reference list of BACS functions to reach is defined in ISO 52120-1:—, Table 6. That table defines
the minimum requirements of BACS functions according to BACS efficiency class C of ISO 52120-1:—,
Table 5.
Unless differently specified this list is used for the following:
— to specify the minimum functions to be implemented for a project;
— to define the BACS function to take into account for the calculation of energy consumption of a
building when the BACS functions are not defined in detail.
— to calculate the energy use for the reference case in step 1 of the BACS efficiency factor method.
5.1.4 Control strategy
The control function is the method employed to achieve a given level of control to reach a goal. Optimal
control strategies deliver a desired level of control at a minimum cost (minimum energy demand).
A control strategy could consist of a control function or a group of control functions. Examples of a
control strategy implemented by a control function are optimum start, optimum stop, or night set back
described in EN 12098-1 and EN 12098-3. The timer function is described in EN 12098-5.
An example of a control strategy that is realized by a group of control functions is the control strategy
used by intermittence. This function uses several control functions, operation modes, optimum start-
stop and timer at the same time. All elements together are called either building profile or user pattern.
Usually, to implement such building profile, a TBM is a prerequisite.
The most important control strategy described and implemented in ISO 52120-1 is demand-oriented
control. Usually these strategies implement the sense of the energy flow (from generation to emission)
with flow of calculation (from building needs to delivered energy). Usually for this complex control
strategy, a TBM is necessary with a distributed specific control for each Technical Building System that
communicates in system architecture via a communication standardized bus such as BACnet, KNX or LON.
More clear, this demand-oriented control works as follows: When the comfort is reached in the emission
area, the controller from the emission sends the message to the controller in charge of distribution
to stop to distribute energy, then the controller in charge of distribution sends the message to the
controller in charge of storage to either store the energy or if the storage cannot store more energy,
then to send the message to the controller in charge of the generation to stop generating more energy.
Another important control strategy is the control strategy for multi generators either from the same
type (e.g. several boilers) or different types (e.g. a boiler and heat pomp) including also the renewable
energy sources. The strategy could be based as follow:
— Priorities only based on running time.
— Fixed sequencing based on loads only: For example depending on the generator's characteristics
(e.g. hot water boiler vs. heat pump).
— Priorities based on generator efficiency and characteristics: the generator operational control is set
individually to available generators so that they operate with an overall high degree of efficiency
(e.g. solar, geothermic heat, cogeneration plant, fossil fuels).
— Load prediction-based sequencing: The sequence is based on, for example efficiency and available
power of a device and the predicted required power.
The standards enabling to calculate the effect of BACS and TBM functions on energy consumption use
different approaches to calculate this impact. The approaches are described in ISO 52120-1:—, 6.4.2.
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5.2 Description of BAC functions
5.2.1 General
The numbers in italics refer to the numbers in ISO 52120-1:—, Table 4.
5.2.2 Heating control
1.1  Heating – Emission control
1.1.0  No automatic control
Description: No automatic control of the room temperature.
1.1.1  Central automatic control
Description: Central automatic control of temperature in rooms by means of heating, is acting either
on the distribution or on the generation. Heating control is performed without consideration of local
demand of different rooms, possibly by using one room as reference. This can be achieved, for example
by an outside temperature controller conforming to EN 12098-1 or EN 12098-3.
Target: To improve EP by minimizing emitted heat by emitters (e.g. radiators) or by air in the building
using central control of temperature and/or flow. This control may be based on outside temperature
and/or a reference sensor inside the building and assumes similar demands in different parts/rooms of
the building.
1.1.2  Individual room control
Description: Individual room control by thermostatic valves or electronic controllers. The individual
room control of heating temperature in rooms is performed either by thermostatic valves or local
(non-communicating) electronic control units. The individual control should/may be combined with
scheduler programs providing different operating modes.
Target: To improve EP by minimizing emitted heat by emitters (e.g. radiators) or by air in the building
using local control of temperature and/or flow in the rooms, thereby adapting to local demand, i.e.
different loads in different rooms.
1.1.3  Individual room control with communication
Description: Individual room control with communication between controllers and to BACS. Individual
control of temperature in rooms by means of heating, with communication between controllers and to
BACS, allows exchange of setpoints, demand and other status information.
Target: To improve EP by minimizing emitted heat by emitters (e.g. radiators
...