Controls for heating systems - Part 4: Optimum start-stop control equipment for electrical systems

This European Standard applies to electronic equipment which controls electrical heating. In this European Standard, equipments are tested to verify conformity with technical characteristics of the materials given by the manufacturer.
NOTE 1   It describes optimal start-stop heating functions. It does not include controls for storage functions and controls for lowest energy cost by controlling the charging of the heating system.
The particular equipment to which this European Standard applies covers both:
·   stand-alone start optimisers or start-stop optimisers, taking priority to the main controller during periods;
·   controllers which contain an integrated optimum start or an optimum start-stop control function;
·   Electrical equipment which includes this function, may includes other.
NOTE 2   Electrical heating systems able to be controlled by these devices (e.g.: direct heating, mixed heating systems including base and supplement, type of emitters, type of storage heating systems, floor heating�) are indicated in the technical documents of the manufacturer. Instructions to adapt the parameters of devices to the systems to which they apply are indicated in these documents. The optimum start-stop function can be integrated within a main control device such as an outside temperature compensated (OTC) controller. In this case the controller would be expected to meet both EN 12098-3 and this document.
It applies both to adaptive and fixed parameters control functions and sets minimum acceptable standards for functions, performance and documentation.

Mess-, Steuer- und Regeleinrichtungen für Heizungen - Teil 4: Ein-/Ausschaltoptimierer für Elektroheizungen

Diese Norm gilt für elektronische Einrichtungen zur Regelung von Elektroheizungen. In dieser Norm werden Einrichtungen geprüft, um die Übereinstimmung mit den technischen Daten der vom Hersteller vorgegebenen Werkstoffe festzustellen.
ANMERKUNG 1   Es werden die optimalen Ein-/Ausschaltfunktionen der Heizung beschrieben. Diese Norm umfasst nicht Mess-, Steuer- und Regeleinrichtungen für Speicherfunktionen und für die niedrigsten Energiekosten durch Gebührenlenkung für die Heizungsanlage.
Diese Norm gilt für spezielle Einrichtungen, die entweder
-   separate Geräte als Einschalt-Optimierer oder Ein-/Ausschalt-Optimierer sind, die gegenüber dem Hauptregler Priorität haben;
-   Regler mit integriertem Einschalt-Optimierer oder Ein-/Ausschalt-Optimierer sind;
-   Elektrische Einrichtungen sind, die diese Funktion umfassen, aber auch andere Funktionen ausführen können.
ANMERKUNG 2   Elektrische Heizsysteme, die durch diese Einrichtungen geregelt werden können (z. B. Direktheizungen, Mischheizungen einschließlich Grund- und Zusatzausrüstung, Heizkörper, Wärmespeicherheizungen, Fußbodenheizungen ) sind in den technischen Unterlagen des Herstellers angegeben. In diesen Unterlagen sind Anweisungen zur Anpassung der Kenndaten der Einrichtungen an die entsprechenden Systeme enthalten. Die optimale Ein-/Ausschalt-Funktion kann in eine Hauptregeleinrichtung, wie z. B. in einem witterungsgeführten Regler (OTC), integriert sein. Dann wird erwartet, dass der Regler sowohl EN 12098-3 als auch diesem Dokument entspricht.
Sie gilt sowohl für adaptive Regler als auch für Regler mit festen Parametern, und sie legt Mindestanforderungen für die Funktionen, das Betriebsverhalten und die Dokumentation fest.
Zusätzliche Funktionen, z. B.:
-   adaptive Funktionen,
-   tarifgeführte Funktionen zur Kostenreduzierung, die für komplexe Tarife von mehr als zwei Tarifgruppen anwendbar sind,
-   Funktionen, die andere Messungen und andere Parameter, die zusätzliche Parameter zur Folge haben, in Betracht

Régulation pour les systèmes de chauffage - Partie 4: Optimiseurs d'intermittences pour les systèmes de chauffage électrique

La présente Norme européenne s’applique aux équipements électroniques de régulation pour les systèmes de chauffage électrique. Dans cette Norme européenne, les appareils sont essayés afin de vérifier la conformité de leurs caractéristiques avec les spécifications données par le fabricant.
NOTE 1   La présente normeElle décrit les fonctions d’optimisation des l’ intermittences du chauffage. Elle ne traite pas des dispositifs de régulation des fonctions de stockage ni de ceux visant à minimiser le coût énergétique en régulant le chargement du des systèmes de chauffage à accumulation.
Les équipements concernés par la présente norme sont :
les optimiseurs autonomes de mise en marche démarrage ou de mise en marche et de mise àdémarrag le et d’arrêt, prenant le pas à certaines périodes sur le régulateur principal ;
oles régulateurs qui intègrent une fonction d’optimisation des intermittences (mise en marche ou mise en marche et à l’arrêtdémarrage ou démarrage et arrêt) ;
les équipements électriques intégrant cette fonction peuvent en comporter d’autres.
NOTE 2   Les systèmes de chauffage susceptibles d’être régulés par ces appareils (par exemple : chauffages directs, chauffages mixtes incluant base et appoint, types d’émetteurs, types de chauffage par accumulation, chauffage par le plancher….) sont indiqués dans les documents techniques du fabricant. Les instructions pour adapter les paramètres des appareils aux systèmes auxquels ils s’appliquent sont données par le fabricant dans ces documents. La fonction d’optimisation peut être intégrée à un dispositif de régulation centralisé comme, par exemple, un régulateur en fonction de la température extérieure (RFTE). Dans ce cas, il est recommandé que le régulateur soit conforme conforme à l’EN 12098-3 et au présent document.aux parties 3 et 6 de la présente norme (voir l’EN 12098-3, « Equipements de régulation en fonction de la température extérieure pour les systèmes de chauffage électrique »).
La norme s’applique aux éq

Regulacijske naprave za grelne sisteme – 4. del: Naprave za optimizacijo delovanja električnih sistemov na osnovi vklop-izklop

General Information

Status
Withdrawn
Publication Date
27-Sep-2005
Withdrawal Date
22-Oct-2013
Current Stage
9960 - Withdrawal effective - Withdrawal
Due Date
23-Oct-2013
Completion Date
23-Oct-2013

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SLOVENSKI STANDARD
SIST EN 12098-4:2006
01-marec-2006

5HJXODFLMVNHQDSUDYH]DJUHOQHVLVWHPH±GHO1DSUDYH]DRSWLPL]DFLMRGHORYDQMD

HOHNWULþQLKVLVWHPRYQDRVQRYLYNORSL]NORS

Controls for heating systems - Part 4: Optimum start-stop control equipment for electrical

systems

Mess-, Steuer- und Regeleinrichtungen für Heizungen - Teil 4: Ein-/Ausschaltoptimierer

für Elektroheizungen

Régulation pour les systemes de chauffage - Partie 4: Optimiseurs d'intermittences pour

les systemes de chauffage électrique
Ta slovenski standard je istoveten z: EN 12098-4:2005
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
97.120 Avtomatske krmilne naprave Automatic controls for
za dom household use
SIST EN 12098-4:2006 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 12098-4:2006
---------------------- Page: 2 ----------------------
SIST EN 12098-4:2006
EUROPEAN STANDARD
EN 12098-4
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2005
ICS 97.100.10; 97.120
English Version
Controls for heating systems - Part 4: Optimum start-stop control
equipment for electrical systems

Régulation pour les systèmes de chauffage - Partie 4: Mess-, Steuer- und Regeleinrichtungen für Heizungen - Teil

Optimiseurs d'intermittences pour les systèmes de 4: Ein-/Ausschalt-Optimierer für Elektroheizungen

chauffage électrique
This European Standard was approved by CEN on 1 August 2005.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European

Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national

standards may be obtained on application to the Central Secretariat or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation

under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official

versions.

CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,

Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,

Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels

© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12098-4:2005: E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN 12098-4:2006
EN 12098-4:2005 (E)
Contents
Page

Foreword ..................................................................................................................................................................3

Introduction..............................................................................................................................................................4

1 Scope ...........................................................................................................................................................6

2 Normative references .................................................................................................................................6

3 Terms and definitions.................................................................................................................................7

4 Functionality..............................................................................................................................................11

5 Graphical symbols and abbreviations.....................................................................................................16

6 Requirements ............................................................................................................................................16

7 Test methods.............................................................................................................................................24

8 Marking ......................................................................................................................................................28

9 Documentation..........................................................................................................................................29

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

---------------------- Page: 4 ----------------------
SIST EN 12098-4:2006
EN 12098-4:2005 (E)
Foreword

This European Standard (EN 12098-4:2005) has been prepared by CEN/TC 247 "Building automation control and

building management", the secretariat of which is held by SNV.

This European Standard shall be given the status of a national standard, either by publication of an identical text or

by endorsement, at the latest by March 2006, and conflicting national standards shall be withdrawn at the latest by

March 2006.

This European Standard is one of a series of product standards for "Controls for heating systems". It considers

Definitions, Functionality, Requirements, Test methods, and Documentation electrical heating controls with

optimum start or optimum start-stop functions. This European Standard consists of the following parts:

Part 1: Outside temperature compensated control equipment for hot water heating systems;

Part 2: Optimum start-stop control equipment for hot water heating systems;

Part 3: Outside temperature compensated control equipment for electrical heating systems;

Part 4: Optimum start-stop control equipment for electrical systems;
Part 5: Start-stop schedulers for heating systems.
No existing European Standard is superseded.

The position of this European Standard in the series of standards for mechanical building services is illustrated

below:
Mechanical building services
Ventilation and
Control for mechanical
Heating systems air conditioning
building services
systems
Individual zone Building management System neutral data
Controls for
control for products and systems for transmission for
heating systems
HVAC applications HVAC applications HVAC applications
Outside Outside
Optimum start- Optimum start-
temperature temperature
stop control stop control Start-Stop
compensated compensated
equipment for hot equipment for schedulers for
control equipment control equipment
water heating electrical heating systems
for hot water for electrical heating
systems heating systems
heating systems systems
Definitions Functionality Requirements Test methods Documentation
HVAC = Heating, Ventilation, Air Conditioning.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following

countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark,

Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

---------------------- Page: 5 ----------------------
SIST EN 12098-4:2006
EN 12098-4:2005 (E)
Introduction

Equipment which controls the heating supply in buildings according to outside and/or room temperature is

necessary to reduce the energy consumption and minimise energy cost of heating plants and maintain comfort

level.
Room thermostat Room thermostat
Emitter Emitter
Room Room
T T
temperature temperature
Outside Outside
temperature temperature
T T
Main electrical supply Main electrical supply
Tariff information Tariff information
Main controller Main controller

Figure 1 - Example of start-stop optimiser. It can control main electrical supply to the central, zone or room

level, it can send data to zone or room controllers

Fixed switching times for intermittent scheduling, may not lead to energy saving, minimum cost and comfort

optimisation. A start-stop optimiser schedules switching times in relation with measured variables and tariff (see

Figure 1). Its function brings a high level of energy saving without reduction of desired comfort. It can complete a

main controller like an outside temperature controller (OTC) according to EN 12098-3.

The optimum start-stop function is easy to programme because the user sets the time at which comfort conditions

should apply, rather than the switch-on or switch-off times of the plant.
Occupation Occupation Occupation
Scheduled
occupation
periods
OSS* function OSS* function OSS* function
Main Main Main
controller control. controller
Start function Stop Start function Stop Start function
Heating
operation
Room
temperature
04 8 12 16 20 24 4 8 12 16 20 24 4 8 Time
00 Hour of day
*OSS : Optimum Start - Stop
Figure 2 - Example of relation between occupation, heating and room temperature
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SIST EN 12098-4:2006
EN 12098-4:2005 (E)

NOTE 1 Optimum start-stop function is illustrated by Figure 2. Heating periods are different from scheduled occupation

periods. These differences, due to thermal inertia, depend mainly on heating loads related with temperatures differences. A

start-stop optimiser controls these switchings, using outside and/or room temperatures or their differences in relation to

setpoints.

Adaptive functions are easier to commission because they require fewer installation parameters to be introduced

and no readjustment.

Additionally, a tariff compensated start controller modify the beginning of the optimum start period with respect to

the electrical energy tariff time, as illustrated in Figure 3.
Tariff
Hight
price
Low
level
Nominal
occupation period
Schedule
occupation
periods
Main
controller
Start function Stop
Heating
operation
Room
temperature °C
24 4 8 12 16 20 24
0 0
Hour of day

Figure 3 - A tariff compensated optimiser shift the start period at the end of the lower tariff level period to

minimise cost

Included in this European Standard are the main equipment characteristics which assist in reaching these energy

saving, minimum costs and comfort objectives.
Characteristics which are directly tested include:
• accuracy of sensors;
• part load characteristics.
Characteristics which are required to be indicated by the manufacturer include:
• time constants.

Other characteristics of the equipment are tested indirectly by measuring responses dependent on them, for

example:
• differential;
• dead band.

NOTE 2 This European Standard, therefore, conforms to the requirements and objectives of the interpretative document n° 6

"Energy Economy and Heat Retention" relating to the Construction Product Directive (89/106/EEC).

---------------------- Page: 7 ----------------------
SIST EN 12098-4:2006
EN 12098-4:2005 (E)
1 Scope

This European Standard applies to electronic equipment which controls electrical heating. In this European

Standard, equipments are tested to verify conformity with technical characteristics of the materials given by the

manufacturer.

NOTE 1 It describes optimal start-stop heating functions. It does not include controls for storage functions and controls for

lowest energy cost by controlling the charging of the heating system.
The particular equipment to which this European Standard applies covers both:

• stand-alone start optimisers or start-stop optimisers, taking priority to the main controller during periods;

• controllers which contain an integrated optimum start or an optimum start-stop control function;

• Electrical equipment which includes this function, may includes other.

NOTE 2 Electrical heating systems able to be controlled by these devices (e.g.: direct heating, mixed heating systems

including base and supplement, type of emitters, type of storage heating systems, floor heating…) are indicated in the technical

documents of the manufacturer. Instructions to adapt the parameters of devices to the systems to which they apply are indicated

in these documents. The optimum start-stop function can be integrated within a main control device such as an outside

temperature compensated (OTC) controller. In this case the controller would be expected to meet both EN 12098-3 and this

document.

It applies both to adaptive and fixed parameters control functions and sets minimum acceptable standards for

functions, performance and documentation.
Additional functions, e.g.:
- adaptive functions,

- tariff compensated function, for cost optimisation applicable for more complex tariffs, including more than two

levels,

- function taking account other measures and other parameters introduced supplementary parameters

should be able to be the object of requirements and test method as complement to this European Standard.

Safety systems and heating control systems remain unaffected by this European Standard. The actuators are not

covered in this European Standard.
This European Standard does not cover heat emitters.
This control equipment can be connected to a data network.
Input and output signal can be processed by analogue or digital techniques.
2 Normative references

The following referenced documents are indispensable for the application 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.

EN 12098-1:1996, Controls for heating systems - Part 1: Outside temperature compensated control equipment for

hot water heating systems

EN 12098-3:2002, Controls for heating systems - Part 3: Outside temperature compensated control equipment for

electrical heating systems

EN 60529, Degrees of protection provided by enclosures (IP code) (IEC 60529:1989)

---------------------- Page: 8 ----------------------
SIST EN 12098-4:2006
EN 12098-4:2005 (E)

EN 60730-1, Automatic electrical controls for household and similar use – Part 1: General requirements (IEC

60730-1:1999, modified)

EN 60730-2-1, Automatic electrical controls for household and similar use – Part 2: particular requirements for

electrical controls for electrical household appliances (IEC 60730-2-1:1989, modified)

EN 60730-2-7, Automatic electrical controls for household and similar use – Part 2: Particular requirements for

timers and time switches (IEC 60730-2-7:1990, modified)

EN 60730-2-9, Automatic electrical controls for household and similar use – Part 2: Particular requirements for

temperature sensing controls (IEC 60730-2-9:2000, modified)

EN 60730-2-11, Automatic electrical controls for household and similar use – Part 2: Particular requirements for

energy controllers (IEC 60730-2-11:1993)
IEC 60038, IEC standard voltages
3 Terms and definitions

For the purposes of this European Standard, the terms and definitions given in EN 12098-1:1996 and the following

apply.
3.1
start-stop optimiser

control device which performs optimum start-stop functions, start function should be tariff compensated. It consists

of the electronic controller, sensors and output signals, but does not include the actuating equipment (see Figure 3).

Main Controller, e.g. : Outside Temperature Compensated
control equipement, according to EN 12098-3
Reference
Start-Stop
variables
Optimiser
Start-Stop-Optimiser, according to EN 12098-4
Set point
Priority
selector
References
Optimiser
variables
functions
Operating modes
Sensors
controller
Actuating
equipment
HEAT
emitters
HEAT
emitters
Figure 4 - Examples of control equipment for heating systems

It overrides signal(s) issued by a controller, from switch-off time to beginning of nominal occupation period. Start-

stop optimisers and control functions can be included in a single device.

The optimum stop function is optional; a start optimiser performs an optimum start function and a fixed switch-off

time function
---------------------- Page: 9 ----------------------
SIST EN 12098-4:2006
EN 12098-4:2005 (E)
3.2
optimum start

function, which controls the switch-on time such that the room temperature reaches the nominal room temperature

from a lower level (e.g. reduced or stand-by room temperature), at a predefined time

NOTE It can lead to switch to the maximal available power.
3.3
tariff compensated optimum start

added function to optimum start function for which the predefined time, ending the optimum start period should be,

either:
• beginning of nominal occupation period
• tariff rising time
automatically chosen with respect to the lowest user energy cost
3.4
adaptive optimum start

An added function to optimum start function, which recalculates the parameters used to determine the switch-on

time, based on variation of the measured room temperature as feedback information.

3.5
optimum stop

function controls the switch-off time, anticipates the end of nominal occupation period in reference to the room

temperature, such that the natural fall of the room temperature during nominal occupation period is kept within

acceptable limits satisfying comfort needs
3.6
adaptive optimum stop

added function to optimum stop, which recalculates the parameters used to determine the switch-off time, based on

variation of the measured room temperature as feedback information
3.7
actuating equipment

equipment providing the means by which the controller affects the heat emitters (according to EN 12098-3:2002,

3.2). See Figure 4
3.8
output signals
signals generated by the optimiser for either:
- heating power
- main controller characteristics heating curve
- temperature settings
3.9
reference variable(s) of the optimiser

for optimum start function: the outside temperature or the room temperature, or both, used to determine the switch-

on time, with or without other influencing variables. See 3.2.

For optimum stop function: the room temperature used to determine the switch-off time, with or without other

influencing variables. See 3.3
3.10
outside temperature

reference variable sensor measuring outside temperature of the building (according to EN 12098-3:2002, 3.6.).

---------------------- Page: 10 ----------------------
SIST EN 12098-4:2006
EN 12098-4:2005 (E)
3.11
nominal room temperature

resulting room temperature in the building arising in nominal operation of the controller. It is dependant on the

design of the heating system and can be different for individual rooms (according to EN 12098-3:2002, 3.8)

3.12
reduced room temperature

reduced room temperature compared with the nominal room temperature resulting from operation at a reduced set

point (according to EN 12098-3:2002, 3.9)
3.13
stand-by room temperature

room temperature resulting from switching off the heating (according to EN 12098-3:2002, 3.10)

Note 1 If frost protection function is active, stand by temperature should be accepted above freezing point.

3.14
beginning of nominal occupation period

user programmed time for which the expected nominal room temperature set point should apply

3.15
tariff rising time

time for witch the electricity cost rises. This information is sent automatically to the optimiser by the energy provider

3.16
switch-on time

point in time at which the controller starts up the heating or modifies the set point in order to reach the nominal

room temperature (according to EN 12098-3:2002, 3.12).

This time is automatically determined by the tariff compensated optimum start function.

The switch on time is a variable based on the user programmed beginning of nominal occupation period

3.17
end of nominal occupation period

The user programmed time for which the nominal temperature should decrease under the nominal room

temperature
3.18
switch-off time

point in time at which the controller switches off the heating or modifies the set point in order to reach the reduced

temperature (according to EN 12098-3:2002, 3.13)
This time is automatically determined by the optimum stop function.

For an optimum stop function, the switch-off time is a variable based on the user programmed end of nominal

occupation period
3.19
nominal occupation period
operating period during which nominal room temperature should apply
3.20
optimum start period

operating period between the switch-on time and the beginning of nominal occupation period

3.21
optimum stop period

operating period between the switch-off time and the end of nominal occupation period

---------------------- Page: 11 ----------------------
SIST EN 12098-4:2006
EN 12098-4:2005 (E)
3.22
reduced operation

operating period from the switch-off time up to the switch-on time, maintaining a reduced room temperature

compared with the nominal room temperature (according to EN 12098-3:2002, 3.15)
3.23
stand-by operation

operating mode in which the heating is switched off or subject to frost-protection room temperature control, if this

function is active (according to EN 12098-3:2002, 3.16)
3.24
manual operation

mode in which the controller is inactive and the actuating equipment can be manipulated manually (according to EN

12098-3:2002, 3.17)
3.25
frost protection function

optional function that prevents freezing inside the building (according to EN 12098-3:2002, 3.18)

3.26
energy prices ratio
P − P
2 1
EPR =
where
P is the low energy price
P is the high energy price
---------------------- Page: 12 ----------------------
SIST EN 12098-4:2006
EN 12098-4:2005 (E)
Room
High tariff Nominal occupation
temperature
anticipation period period
Time
A' (x) A' (o) A (x) A (o) B (x) B (o)
Tariff
High
Low
Time
A' (o)
Key
1 nominal room temperature
2 : reduced room temperature

3 : stand-by room temperature (e.g.: temperature reached by frost protection function)

A(o) - B(o): nominal occupation period
A(x) - A(o) or A’(x) – A’(o): optimum start period *
A(o): beginning of nominal occupation period (user programmed)
B(x) - B(o): optimum stop period **
A’(o): tariff rising time
B(x) - A(o) or B(x) – A’(o): priority to the start-stop optimiser
A(x) or A’(x): switch-on time (variable related to inputs)
A(o) - B(x) or A’(o) – B(x): priority to a main controller
B(o): end of nominal occupation period (user programmed)
A(o) – A’(o): high tariff period before nominal occupation
B(x): switch-off time (variable related to inputs)
* Influenced by outside and/or room temperature
** Influenced by room temperature
Figure 5 - Temperature-time curve
4 Functionality
4.1 Functional objectives
4.1.1 General

Optimum start-stop control equipment achieves high levels of energy saving by reducing, or preferably, switching

off heating systems and controlling optimum start heating period by taking account the thermal inertia of the

building and heating system, in such a way that the recovery to the nominal room temperature from a lower room

temperature is done in the minimum time. If an energy tariff rise occurs during or just before the optimum start

period, the energy cost is not as lower as possible. In such cases, energy cost should be lowered by an anticipation

of the beginning of the optimum start period by the tariff compensated optimum start function.

The start period duration and the controlled variable are relative to reference variable(s) which fall into three

classes:

Class A : reference variable is measured outside temperature (and temperature setpoints), with or without other

influencing variables. It is completed by tariff rising time input.
---------------------- Page: 13 ----------------------
SIST EN 12098-4:2006
EN 12098-4:2005 (E)

Class B : reference variable is measured room temperature (and temperature setpoints), with or without other

influencing variables. It is completed by tariff rising time input.

Class C : reference variables are measured outside and room temperature (and temperature setpoints), with or

without other influencing variables. It is completed by tariff rising time input.

Classes may be capable of more than one function. Table 1 shows those possibilities:

Table 1 - Classes
Tariff compensated Optimum Adaptive optimum start or
Classes Optimum stop
start start adaptive optimum stop
A optional yes no no
B optional yes optional optional
C optional yes optional optional
4.1.2 Optimum start (Class A , B , C )
e e e

The aims are to save energy minimise cost and satisfy comfort needs during nominal occupation period. This is

achieved by assuming the thermal behaviour of the heating plant and building, switching on and controlling the

heating plant, such that the room temperature rises rapidly from the stand-by or reduced level to its target level at

the start of the nominal occupation period or at the tariff rising time the optimum start period may be limited by

design or a user parameter.
4.1.3 Adaptive optimum start (Class B , C )
e e

An additional aim to optimum start is to make the control easy to use and apply to many applications with the

minimum of adjustment.

This is achieved by periodically modifying the characteristic optimum start curve, with knowledge of the dynamic

thermal behaviour of the heating plant and the building, to minimise the time error from the defined start time of the

nominal period. Adaptation may be permanently enabled or disabled and/or enabled for a specified number of

adaptation cycles or until an optimum condition is met.
4.1.4 Optimum stop (Class B , C )
e e

The aims are to save energy and maintain a comfort level before the end of a nominal occupation period. This is

achieved by assuming the thermal behaviour of the heating plant and building, switching off or reducing the heating

before the end of the nominal occupation period such that the room temperature does not fall below the nominal

room temperature. This lower level may be less than the achieved comfort level at the start and during the nominal

operation period. The maximum value of the optimum stop period may be limited by design or a user parameter.

4.1.5 Adaptive optimum stop (Class B , C )
e e

An additional aim to optimum stop is to make the control easy to use and applied to many applications with the

minimum of adjustment.

This is achieved by periodically modifying the characteristic optimum stop curve, with knowledge of the dynamic

thermal behaviour of the heating plant and the building, to produce an acceptable comfort level at the end of the

nominal occupation period and to maximise the switch-off time and/or the reduction in energy level. This end

comfort level may be less than the achieved comfort level at the start of the nominal occupation period. Adaptation

may be permanently enabled or disabled and/ or enabled for a specified number of adaptation cycles or until an

optimum condition is met.
NOTE Some other functions can be added to intermittent heating control function:
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SIST EN 12098-4:2006
EN 12098-4:2005 (E)

 allow comfort temperature to rise during a limited duration after start of occupancy, for comfort and/or cost saving

needs;

 automatically offset reduced room temperature level. When the heating load is near maximal power and abnormally

long optimum start times are required the reduced room temperature can be raised closer to the comfort

temperature;

 cold wall effect compensation. An averaging method of air and wall temperatures to allow for different structures;

 compensate for long unoccupied periods (or long periods at a reduced temperature) with a significant extra energy

input to achieve the specified temperature and time requirements. The long-term thermal behaviour of buildings can

often necessitate longer anticipation times than would normally be expected. Sometimes known as the Monday

morning effect.;

 a maximum optimum start period is generally regarded by the users and energy managers as a desirable

requirement;

 the model described in this standard takes into account two electrical price levels. Devices should include

algorithms adopted to three or more price (predictable) levels. These equipments should be adapted to specific

utilities prices.
4.2 Control equipment functionality
Optimum start
Optimum stop Energy prices: low Operation mode
parameters
parameters and high settings
Frost settings
Clock settings
Optimum stop
Optimum start
Adaptative Adaptative
function function
Tariff rising time
escclasses)
Ouput Signal(s)
Outside Sensor
Optimiser
(Class A ,C )
e e
Room Sensor
Status to
(Classes B ,C )
e e
controller
Other reference
variable
Figure 6 - Block schematic of optimum start–stop control equipment
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SIST EN 12098-4:2006
EN 12098-4:2005 (E)
4.3 Function block(s)
Class INPUTS OUTPUTS
Tariff rising time TT
B , C Room temperature............................ Real TR (Classes B, C
e e e e
only)
A , C Outside temperature......................... Real TO (Classes A, C
e e e e
only)
Other reference variables................. Real TX
Controlled variable............................ Real TW PO VAR Actuating
Actual Time...................................... Real t equipment
STATUS Boolean
PARAMETERS for separate
optimiser an
...

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