CEN/TR 16798-14:2017

SLOVENSKI STANDARD
01-julij-2018
1DGRPHãþD
SIST EN 15243:2007
(QHUJLMVNHODVWQRVWLVWDYE3UH]UDþHYDQMHVWDYEGHO5D]ODJDLQXWHPHOMLWHY
(1,]UDþXQ]DKODGLOQHVLVWHPH0RGXO03URL]YRGQMD
Energy performance of buildings - Ventilation for buildings - Part 14: Interpretation of the
requirements in EN 16798-13 - Calculation of cooling systems (Module M4-8) -
Generation
Energieeffizienz von Gebäuden - Lüftung von Gebäuden - Teil 14: Interpretation der
Anforderungen der EN 16798-13 - Berechnung von Kühlsystemen (Modul M4-8) -
Erzeugung
Performance énergétique des bâtiments - Ventilation des bâtiments - Partie 14 :
Interprétation des exigences de l'EN 16798-13 - Calcul des systèmes de refroidissement
(Module M4-8) - Génération
Ta slovenski standard je istoveten z: CEN/TR 16798-14:2017
ICS:
91.140.30 3UH]UDþHYDOQLLQNOLPDWVNL Ventilation and air-
VLVWHPL conditioning systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TR 16798-14
TECHNICAL REPORT
RAPPORT TECHNIQUE
June 2017
TECHNISCHER BERICHT
ICS 91.140.30; 91.120.10 Supersedes EN 15243:2007
English Version
Energy performance of buildings - Ventilation for buildings
- Part 14: Interpretation of the requirements in EN 16798-
13 - Calculation of cooling systems (Module M4-8) -
Generation
Energieeffizienz von Gebäuden - Lüftung von
Gebäuden - Teil 14: Interpretation der Anforderungen
der EN 16798-13 - Berechnung von Kühlsystemen
(Modul M4-8) - Erzeugung
This Technical Report was approved by CEN on 27 February 2017. It has been drawn up by the Technical Committee CEN/TC
156.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 16798-14:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 7
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 9
4 Symbols, subscripts and abbreviations. 9
5 Brief description of the methods and routing . 9
5.1 Output of the method . 9
5.2 General description of the methods . 9
5.2.1 Method A. 9
5.2.2 Method B. 10
5.3 Selection criteria between the methods . 10
6 Calculation method - Method A . 11
6.1 Output data . 11
6.2 Calculation time interval and calculation period . 11
6.3 Input data . 11
6.3.1 Source of data . 11
6.3.2 Product data — Product technical data . 12
6.3.3 System design data . 13
6.3.4 Operating conditions . 13
6.3.5 Constants and physical data . 13
6.4 Calculation procedure . 13
6.4.1 Applicable calculation interval . 13
6.4.2 Operating conditions calculation . 13
6.4.3 Energy calculation . 14
7 Calculation method - Method B . 14
7.1 Output data . 14
7.2 Calculation time interval and calculation period . 14
7.3 Input data . 14
7.3.1 Product description data (qualitative) . 14
7.3.2 Product technical data . 15
7.3.3 System design data . 15
7.3.4 Operating conditions . 16
7.3.5 Simplified input . 16
7.4 Calculation procedure . 20
7.4.1 Assumptions . 20
7.4.2 Possible origin of errors . 20
7.4.3 Possible iteration convergence problems . 20
8 Quality control . 20
9 Compliance check. 20
10 Worked out examples, method A — Example 1 . 20
10.1 Description . 20
10.2 Calculation details . 30
10.3 Observations . 30
11 Worked out examples, method B . 31
11.1 Example 1 . 31
11.1.1 Description . 31
11.1.2 Calculation details . 31
11.2 Example 2 . 31
11.2.1 Description . 31
11.2.2 Calculation details . 31
12 Validation of the calculation procedures . 32
Annex A (informative) Input and method selection data sheet — Template . 33
A.1 General . 33
A.2 References . 33
A.3 Method A . 33
A.4 Method B . 33
Annex B (informative) Input and method selection data sheet — Default choices . 34
B.1 General . 34
B.2 References . 34
B.3 Method A . 34
B.4 Method B . 34
Annex C (informative) Calculation examples . 35
C.1 Spreadsheets . 35
C.2 Method A, example 1 . 35
C.3 Method B, example 1 . 50
C.4 Method B, example 2 . 57
Annex D (informative) Illustrative Example of Estimation of Seasonal EER . 64
D.1 Introduction. 64
D.2 Load frequency distributions . 64
Bibliography . 68

European foreword
This document (CEN/TR 16798-14:2017) has been prepared by Technical Committee CEN/TC 156
“Ventilation for buildings”, the secretariat of which is held by BSI.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document supersedes EN 15243:2007.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
The necessary editorial revisions were made to comply with the requirements for each EPB Technical
Report.
This document has been produced to meet the requirements of Directive 2010/31/EU 19 May 2010 on
the energy performance of buildings (recast), referred to as “recast EPDB”.
For the convenience of Standards users CEN/TC 156, together with responsible Working Group
Convenors, have prepared a simple table below relating, where appropriate, the relationship between
the ‘EPBD’ and ‘recast EPBD’ standard numbers prepared by Technical Committee CEN/TC 156
“Ventilation for buildings”.
EPBD EN Recast EPBD EN
Title
Number Number
Energy performance of buildings – Ventilation for buildings –
Part 1: Indoor environmental input parameters for design
EN 15251 EN 16798-1 and assessment of energy performance of buildings
addressing indoor air quality, thermal environment, lighting
and acoustics (Module M1-6)
Energy performance of buildings – Ventilation for buildings –
Part 2: Interpretation of the requirements in EN 16798-1 –
Indoor environmental input parameters for design and
N/A CEN/TR 16798-2
assessment of energy performance of buildings addressing
indoor air quality, thermal environment, lighting and
acoustics (Module M1-6)
Energy performance of buildings – Ventilation for buildings –
Part 3: For non-residential buildings – Performance
requirements for ventilation and room-conditioning systems
EN 13779 EN 16798-3
(Modules M5-1, M5-4)
Energy performance of buildings – Ventilation for buildings –
Part 4: Interpretation of the requirements in EN 16798- 3 –
N/A CEN/TR 16798-4 For non-residential buildings – Performance requirements
for ventilation and room-conditioning systems (Modules M5-
1, M5-4)
Energy performance of buildings – Ventilation for buildings –
Part 5-1: Calculation methods for energy requirements of
ventilation and air conditioning systems (Modules M5-6, M5-
EN 15241 EN 16798-5-1
8, M6-5, M6-8, M7-5, M7-8) – Method 1: Distribution and
generation
Energy performance of buildings – Ventilation for buildings –
Part 5-2: Calculation methods for energy requirements of
ventilation systems (Modules M5-6.2, M5-8.2) – Method 2:
EN 15241 EN 16798-5-2
Distribution and generation
Energy performance of buildings – Ventilation for buildings –
Part 6: Interpretation of the requirements in EN 16798-5–1
N/A CEN/TR 16798-6 and EN 16798-5-2 – Calculation methods for energy
requirements of ventilation and air conditioning systems
(Modules M5-6, M5-8, M 6-5, M6-8 , M7-5, M7-8)
Energy performance of buildings – Ventilation for buildings –
Part 7: Calculation methods for the determination of air flow
EN 15242 EN 16798-7
rates in buildings including infiltration (Module M5-5)

Energy performance of buildings – Ventilation for buildings –
Part 8: Interpretation of the requirements in EN 16798-7 –
N/A CEN/TR 16798-8
Calculation methods for the determination of air flow rates in
buildings including infiltration – (Module M5-5)
Energy performance of buildings – Ventilation for buildings –
EN 15243 EN 16798-9 Part 9: Calculation methods for energy requirements of
cooling systems (Modules M4-1, M4-4, M4-9) – General
Energy performance of buildings – Ventilation for buildings –
Part 10: Interpretation of the requirements in EN 16798-9 –
Calculation methods for energy requirements of cooling
N/A CEN/TR 16798-10
systems (Module M4-1,M4-4, M4-9) – General

Energy performance of buildings – Ventilation for buildings –
EN 15243 EN 16798-13 Part 13: Calculation of cooling systems (Module M4-8) –
Generation
Energy performance of buildings – Ventilation for buildings –
EN 15243 CEN/TR 16798-14 Part 14: Interpretation of the requirements in EN 16798-13 –
Calculation of cooling systems (Module M4-8) – Generation
Energy performance of buildings – Ventilation for buildings –
N/A EN 16798-15 Part 15: Calculation of cooling systems (Module M4-7) –
Storage
Energy performance of buildings – Ventilation for buildings –
N/A CEN/TR 16798-16 Part 16: Interpretation of the requirements in EN 16798-15 –
Calculation of cooling systems (Module M4-7) – Storage
Energy performance of buildings – Ventilation for buildings –
EN 15239 and
EN 16798-17 Part 17: Guidelines for inspection of ventilation and air-
EN 15240
conditioning systems (Module M4-11, M5-11, M6-11, M7-11)
Energy performance of buildings – Ventilation for buildings –
Part 18: Interpretation of the requirements in EN 16798-17 –
N/A CEN/TR 16798-18
Guidelines for inspection of ventilation and air-conditioning
systems (Module M4-11, M5-11, M6-11, M7-11)

Introduction
The set of EPB standards, Technical Reports and supporting tools
In order to facilitate the necessary overall consistency and coherence, in terminology, approach,
input/output relations and formats, for the whole set of EPB-standards, the following documents and
tools are available:
a) a document with basic principles to be followed in drafting EPB-standards: CEN/TS 16628, Energy
Performance of Buildings — Basic Principles for the set of EPB standards [1];
b) a document with detailed technical rules to be followed in drafting EPB-standards; CEN/TS 16629,
Energy Performance of Buildings — Detailed Technical Rules for the set of EPB-standards [2]; and
c) the detailed technical rules are the basis for the following tools:
1) a common template for each EPB-standard, including specific drafting instructions for the
relevant clauses,
2) a common template for each technical report that accompanies an EPB standard or a cluster of
EPB standards, including specific drafting instructions for the relevant clauses, and
3) a common template for the spreadsheet that accompanies each EPB standard, to demonstrate
the correctness of the EPB calculation procedures.
Each EPB-standard follows the basic principles and the detailed technical rules and relates to the
overarching EPB-standard, EN ISO 52000-1 [3].
One of the main purposes of the revision of the EPB-standards is to enable that laws and regulations
directly refer to the EPB-standards and make compliance with them compulsory. This requires that the
set of EPB-standards consists of a systematic, clear, comprehensive and unambiguous set of energy
performance procedures. The number of options provided is kept as low as possible, taking into
account national and regional differences in climate, culture and building tradition, policy and legal
frameworks (subsidiarity principle). For each option, an informative default option is provided
(Annex B).
Rationale behind the EPB Technical Reports
There is a risk that the purpose and limitations of the EPB standards will be misunderstood, unless the
background and context to their contents – and the thinking behind them – is explained in some detail
to readers of the standards. Consequently, various types of informative contents are recorded and made
available for users to properly understand, apply and nationally or regionally implement the EPB
standards.
If this explanation would have been attempted in the standards themselves, the result is likely to be
confusing and cumbersome, especially if the standards are implemented or referenced in national or
regional building codes.
Therefore each EPB standard is accompanied by an informative technical report, like this one, where all
informative content is collected, to ensure a clear separation between normative and informative
contents (see CEN/TS 16629 [2]):
— to avoid flooding and confusing the actual normative part with informative content;
— to reduce the page count of the actual standard; and
— to facilitate understanding of the set of EPB standards.
This was also one of the main recommendations from the European CENSE project [5] that laid the
foundation for the preparation of the set of EPB standards.
This Technical Report
This Technical Report accompanies the suite of EPB standards on ventilation for buildings. It relates to
the European standard EN 16798-13, which forms part of a set of standards related to the evaluation of
the energy performance of buildings (EPB).
The role and the positioning of the accompanied standard in the set of EPB standards is defined in the
Introduction to the standard.
Accompanying spreadsheets
Concerning the accompanied standard EN 16798-13, the following spreadsheets were produced:
— EN 16798-13, Method A;
— EN 16798-13, Method B, example 1; and
— EN 16798-13, Method B, example 2.
In this Technical Report, examples of each of these calculation sheets are included.
1 Scope
This Technical Report refers to the standard EN 16798-13.
It contains information to support the correct understanding and use of this standard.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
NOTE More information on the use of EPB module numbers for normative references between EPB standards
is given in CEN ISO/TR 52000-2.
EN 14511 (all parts), Air conditioners, liquid chilling packages and heat pumps with electrically driven
compressors for space heating and cooling
EN 14825, Air conditioners, liquid chilling packages and heat pumps, with electrically driven compressors,
for space heating and cooling - Testing and rating at part load conditions and calculation of seasonal
performance
EN 16798-13, Energy performance of buildings — Part 13: Module M4-8 — Calculation of cooling
systems — Generation
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 16798-13 apply.
NOTE More information on some key EPB terms and definitions is given in CEN ISO/TR 52000-2.
4 Symbols, subscripts and abbreviations
For the purposes of this document, the symbols, subscripts and abbreviations as mentioned and given
in the accompanied EPB standard, EN 16798-13, apply.
More information on key EPB symbols is given in CEN ISO/TR 52000-2.
5 Brief description of the methods and routing
5.1 Output of the method
No additional information beyond the accompanied standard.
5.2 General description of the methods
5.2.1 Method A
The method is designed for an hourly calculation, based on the operational conditions and system
design possibilities. It covers the cooling generator calculation including multiple generators, the heat
rejection devices and its control, and includes the possibility of “free cooling” in form of bypassing the
generator and using the heat rejection device directly when the climate conditions allow for. Also, heat
to be rejected is offered as a potential heat to be recovered on the heating/domestic hot water side.
Three different generator types are distinguished: compression chillers, absorption chillers and a
“generic” type labelled “OTHER”, to cover e.g. the direct use of heat sinks like ground (boreholes),
ground water or surface water.
Three approaches are offered to calculate the compression chiller characteristics:
— characteristics based on EN 14825 values;
— characteristics based on one nominal EER (EN 14511 (all parts)); and
— unknown performance data.
For the heat rejection, dry, wet and mixed mode (hybrid) heat rejecters are covered as well as the use of
other heat sinks as ground, ground water or surface water, in association with the respective control
options.
5.2.2 Method B
The method is designed for an hourly or monthly calculation, based on the operational conditions and
system design possibilities. It covers the cooling generator calculation including the heat rejection and
includes the possibility of “free cooling” in form of bypassing the generator and using the heat rejection
device directly when the climate conditions allow for. Also, heat to be rejected is offered as a potential
heat to be recovered on the heating/domestic hot water side.
Two different generator types are distinguished: compression chillers, absorption chillers. Moreover,
direct-evaporating room air-conditioning systems are also applicable. See Method A for other systems,
such as, the direct use of heat sinks like ground (boreholes), ground water or surface water. Tabulated
or measured part-load data should be employed for the evaluation of the part-load behaviour.
For the heat rejection, dry, wet and mixed mode (hybrid) heat rejecters are covered.
The calculation includes the operation and control of multi generator set ups.
5.3 Selection criteria between the methods
The criteria for method selection are summarized in Table 1.
Table 1 — Criteria for method selection
Criterion Method Method
A B
System status
Existing cooling generation system x x
New cooling generation system x x
Availability of data
Detailed part-load data according to EN 14825 available x
Detailed part-load data according to EN 14825 not available x x
System type
Compression or absorption chiller systems x x
Multi-split room air conditioning systems  x
Other heat sinks (e.g. ground source heat exchanger, x
aquifer,)
Calculation interval
Hourly x x
Monthly  x
Bin method x
Climatic data/pre calculated factors
Factors in compliance with climate or calculated  x
Factors not in compliance with climate or not calculated x

6 Calculation method - Method A
6.1 Output data
No additional information beyond the accompanied standard.
6.2 Calculation time interval and calculation period
The method is designed for an hourly calculation interval.
Applications to any other calculation intervals and bins add complexity. An application in a bin method
structure is possible, if the load distribution to the temperature bins can be reasonably determined. An
example calculation for this, originating from EN 15243, is given in Annex D.
Refer to method B for longer calculation intervals.
6.3 Input data
6.3.1 Source of data
No additional information beyond the accompanied standard.
6.3.2 Product data — Product technical data
6.3.2.1 General
No additional information beyond the accompanied standard.
6.3.2.2 Compression chiller coefficients
6.3.2.2.1 Characteristics based on EN 14825 values
To model the characteristics based on EN 14825 values, a semi-physical/semi-empirical model (grey
box) model is used, which is designed to require a minimum of input to characterize a performance map
in the space of part load ratio and temperature lift. The model requires four coefficients C , C , C , and C
1 2 3 4
and a correction temperature difference Δϑ . The background and testing of the model is described in
corr
[6].
The determination of these values from supplier's data are described with Formulae (1) and (2). The
required supplier's data are the four values EER , used for the SEER calculation in EN 14825, in
A, B, C, D
association with the conditions of their measurement (Table 7 in the accompanied standard). These
data (but not the SEER value itself) are used as an input for this method.
The method to solve the equation system of Formula (1) for the five unknown variables C , C , C , C and
1 2 3 4
Δϑ is based on linear algebra, using the matrix inversion technique. It is implemented in the
corr
spreadsheet to this method of the accompanied standard (see Annex C, C.1).
Due to the unfavourable distribution of these four points for this purpose, a fifth EER value at an
operation point outside of the range is needed. This operational point can theoretically be freely chosen,
but is preferably the 50 % part load value at temperature conditions for the full load value. However,
since this value is not necessarily available, a default calculation for this is given with Formula (2). With
this formula the Δϑ becomes 0.
corr
It will be mandatory for manufacturers/suppliers as from the year 2018, to provide the SEER according
to EN 14825. Therefore, it can be expected that also the data of the four operation points will be
available and the method can be applied. In many cases they can be calculated with the software
provided by the manufacturer, which allows the calculation of the EER at different conditions. This is
even true for the 5th point.
Alternatively to this method, the performance can be described by interpolation of tabled values, if
more detailed data are provided.
6.3.2.2.2 Characteristics based on one nominal EER (EN 14511 (all parts))
Since the publication of the SEER values is not yet mandatory at the time of the publication of the
accompanied standard, an alternative calculation is offered, based on the nominal EER , obtained from
n
tests according to EN 14511 (all parts). See comment to Formula (19) below for the application in the
calculation.
6.3.2.2.3 Unknown performance data
In the absence of the EN 14511 test value, an EER value defined on a national basis following the
n
template given in Table A.2 can be used in the same way.
6.3.2.3 Absorption chiller characteristics
For the absorption chiller characteristic, a quadratic equation is used.
6.3.2.4 Other generator characteristics
Any generator, the performance of which can be described by a performance map generated by
interpolation of tabled values, can be covered in the calculation, using the generator type “OTHER”.
For generic generator types (type OTHER), a function f (ϑ ; ϑ ; f ) to describe the heat
l C;gen;out sk;l C;PL;l
extraction of the generator depending on the generation outlet temperature, the sink temperature and
the part load ratio, to be applied as a factor on the required cooling energy intake, is assumed. The exact
form of the function is not given and should be defined for specific cases. In the simplest case, this may
be a constant factor (e.g. representing a circulation pump consuming energy proportional to the
required cooling generation energy intake).
6.3.3 System design data
No additional information beyond the accompanied standard.
6.3.4 Operating conditions
No additional information beyond the accompanied standard.
6.3.5 Constants and physical data
No additional information beyond the accompanied standard.
6.4 Calculation procedure
6.4.1 Applicable calculation interval
See 6.2.
6.4.2 Operating conditions calculation
The operation conditions calculation defines the operational boundary conditions for the operation of
the generation systems. It includes the calculation of the condenser inlet temperature for dry and for
wet operation (Formula (3); both are needed to decide on the operation in case of hybrid heat rejection
devices), and of the generator outlet temperature, which is delivered by the generation system to the
cooling distribution system (Formula (4)). For compression and absorption chillers the evaporator
outlet temperature is set to that value (Formula (5)).
In Formula (4) the required generation outlet temperature is needed as an input value. This value is an
input variable originating from the module M4-1 standard. It might be expected that the issue of
controlling the generation outlet temperature, offering the options of constant or variable generation
outlet temperatures, would be given here. This is, however, covered in the module M4-1 standard,
because it is also involving the influence of, e.g. the storage charging/discharging operation.
Formula (6) is used to define the possibility of free cooling operation.
In Formulae (7) to (12), the operation of multiple generator settings is calculated, based on a given
priority for the different chillers. The priority is assumed to be an input from the module M10-12
standard, based on information on the required energy to be extracted, the number of generators and
the maximum hourly heat extraction of all generators, which is delivered as an output to that module.
In Formulae (13) and (14), the heat rejection operation is defined, depending on the heat rejection type
and its control. For air cooled condensers, the heat rejection circuit is not present, and the condenser
inlet temperature becomes the outdoor air temperature, if it is above the limit, which is an input
parameter. For all other types, there is a circuit, which ads a temperature difference for the heat
exchange and another one for the heat losses of the circuit (calculated in Formula (3)). For HYBRID heat
rejection devices, there are two control options for the switch between dry and wet operation: For the
TEMP option, a fixed outdoor temperature limit is used for the switch, independent of the energy to be
extracted. For the MAX_POWER option, the switch is only done if the sum of all generators cannot meet
the required energy to be extracted at dry conditions in the current calculation interval.
6.4.3 Energy calculation
In Formula (15), the total heat really extracted at the current calculation interval is calculated based on
all operational conditions. The heat input to the absorption chillers in this formula is an input from the
heating module M3-1 standard, which is a reaction of this module to the required heat input from
Formula (20).
The total heat potentially recoverable to be rejected or is calculated in Formula (16), and its proportion
which is potentially recoverable in Formula (17). This information is delivered as an offer to the
heating/domestic hot water modules, i.e. the module M3-1/M8-1 standard. Whether it is really
recovered, is an input from these modules and is taken into account in the heat rejection calculation in
Formula (26).
The required electric energy for the compression chillers and for the generic types of generators are
calculated with Formulae (18) to (20) and (24). In Formulae (20)a) and (20b) the compression chiller
characteristics from Formulae (1) and (2) is used. The approach in Formula (20)c), based on a nominal
EER from EN 14511 (all parts) or a default value, is a constant exergetic efficiency.
n
The required heat input for the absorption chillers from Formulae (21) to (23) is reported to the
module 3-1 standard as a request.
The auxiliary energy for the generation system consists of the three parts for the heat rejection device,
the heat rejection circulation pump and the control devices and is calculated in Formulae (25) to (28).
7 Calculation method - Method B
7.1 Output data
No additional information beyond the accompanied standard.
7.2 Calculation time interval and calculation period
The typical calculation intervals for this method are:
— hourly; or
— monthly.
Other calculation intervals can be applied, but their results might be questionable.
Dynamic effects are not taken into account. However, this procedure is suitable for dynamic simulations
especially in conjunction with thermal storages or detailed building and system simulations.
7.3 Input data
7.3.1 Product description data (qualitative)
The product description data comprises:
— refrigeration system type, REFR_TYPE;
— cooling generation system type, GEN_TYPE;
— compressor type, COMP_TYPE;
— compressor control type, COMP_CTRL_TYPE;
— room air-conditioning system zoning, AIR_CLG_RAC_ZONE_TYPE;
— air-cooled heat rejection, AIR_CLG_HEAT_REJ; and
— heat rejection system type, HEAT_REJ_TYPE.
These data are known from the component manufacturer's data sheets and are considered to be
constant during the lifetime of the respective system component.
7.3.2 Product technical data
The following technical data are usually obtained experimentally and provided by the manufacturer.
These are constant during the lifetime of the respective system component:
— nominal thermal power of the refrigeration unit, ΦC;gen;n;
— nominal thermal power of heat rejection system, Φ ;
hr;n
— nominal thermal power of hybrid heat rejection system in dry operation mode, Φ ;
hr;n;dry
— nominal energy efficiency ratio, EER ;
n
— nominal heat ratio, ζ ;
n
— ambient temperature for air-cooled system nominal energy efficiency ratio, ϑ ;
e;n
— reference ambient temperature for air-cooled systems, ϑ ;
e;ref
— internal temperature for air-cooled system nominal energy efficiency ratio, ϑ ;
i;n
— reference heat rejection inlet cooling water temperature, ϑ ;
C;wat;hr;in;ref
— nominal heat rejection outlet cooling temperature water, ϑ ;
C;wat;hr;out;ref
— specific electrical energy for heat rejection, p ;
hr;el
— specific electrical energy for distribution, p ;
dist;el
— evaporator temperature difference, Δϑ ;
evap
— condenser temperature difference, Δϑ ;
cond
— various coefficients describing the heat rejection performance, a , a , a , b , b ; and
0 1 2 0 1
— electrical power required for control, actors, sensors, etc., P .
ctrl;el;j
7.3.3 System design data
7.3.3.1 Process design
The design data of cooling generation systems is usually defined when the system is installed. The data
can be obtained from manufacturer's data sheets. These are:
— the cooling generation control, CLG_GEN_TMP_CTRL;
— the multiple cooling generator arrangement, CLG_GEN_ARR; and
— the heat rejection control, HEAT_REJ_CTRL.
7.3.3.2 Control
The control description data of cooling generation systems – the hybrid heat rejection control,
HBRD_HEAT_REJ_CTRL – varies with the time and their state is derived from measured conditions.
7.3.4 Operating conditions
The operating conditions data for this calculation procedure shall be obtained by measurements and
are depending upon the time. These are:
— required thermal energy to extraction by refrigeration unit, Q ;
C,gen,in,req
— required thermal energy for recovery, Q ;
C,gen,out,req
— cooling generation operation time interval, tC,gen,op;
;
— required cooling generation output temperature, ϑC;wat;req;out
— ambient air temperature, ϑ ;
e
— ambient air wet-bulb temperature, ϑ ;
e;wb
— part-load factor at particular part-load stage, f ;
C;PL;k
— energy efficiency correction factor, f ;
EER;corr
— free-cooling factor, f ;
hr;fc
— electrical free-cooling factor, f ;
hr;fc;el
— multiple-generator factor, f ;
C;mult
— electrical heat rejection part-load factor, f ; and
hr;PL;el
— absorption type system part-load value, PLVabs.
NOTE Both the free-cooling and electrical free-cooling factors are provided with a single default value in the
standard. Examples for annual values of various applications can be found in 7.3.5.
7.3.5 Simplified input
7.3.5.1 Part-load data
The default part-load factors for air- and water-cooled chiller systems with variable part-load control
other than by inverter (i.e. COMP_CTRL_TYPE = VARIABLE_OTHER) are given in Table 2. These figures
and also the corresponding ones in the companying standard are gathered from manufacturer’s data.
Table 2 — Part-load factors f for chiller systems
C,PL,k
System of
Part-load stage k
COMP_CTRL_TYPE = VARIABLE_OTHER
0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0
Air-cooled systems
Screw compressor with distributor valve
0,47 0,51 0,66 0,80 0,88 0,76 0,85 0,91 0,95 1,00
control
Water-cooled systems
Piston compressor with cylinder
0,44 0,54 0,62 0,70 0,76 0,82 0,88 0,92 0,96 1,00
disconnection
Piston or scroll compressor with hot-gas by-
0,30 0,33 0,43 0,52 0,61 0,70 0,78 0,87 0,93 1,00
pass control
Screw compressor with distributor valve
0,45 0,67 0,80 0,91 0,99 1,03 1,05 1,04 1,02 1,00
control
Centrifugal compressor with inlet throttle
0,50 0,72 0,84 0,93 0,99 1,01 1,03 1,02 1,01 1,00
control
7.3.5.2 Free-cooling factors
Illustrative examples for the free-cooling factors f and f are tabulated in Table 3 (alternative
HR;FC HR;FC;el
operation mode) and Table 4 (parallel operation mode in heat rejection system with integrated free-
cooling registers). The data in both tables have been obtained from hourly simulations assuming
German weather conditions.
Table 3 — Free-cooling factors for heat rejection systems in alternative operation mode
Kind of Tempera Free-cooling factors fHR;FC and fHR;FC;el in alternative operation mode
utilization tures
Dry heat rejection system Wet heat rejection system
in °C
Light-weight Massive Light-weight Massive
a b a b
construction construction construction construction
f f f f f f f f
HR;FC HR;FC;el HR;FC HR;FC;el HR;FC HR;FC;el HR;FC HR;FC;el
Office, side room 6/12 1,00 1,00
...