SIST ENV 12977-3:2002

SLOVENSKI STANDARD
01-november-2002
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Thermal solar systems and components - Custom built systems - Part 3: Performance
characterisation of stores for solar heating systems
Thermische Solaranlagen und ihre Bauteile - Kundenspezifisch gefertigte Anlagen - Teil
3: Leistunsprüfung von Warmwasserspeichern für Solaranlagen
Installations solaires thermiques et leur composants - Installations assemblées a façon -
Partie 3: Caractérisation des performances des dispositifs de stockage pour des
installations de chauffage solaire
Ta slovenski standard je istoveten z: ENV 12977-3:2001
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
91.140.65 Oprema za ogrevanje vode Water heating equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN PRESTANDARD
ENV 12977-3
PRÉNORME EUROPÉENNE
EUROPÄISCHE VORNORM
April 2001
ICS 27.160; 91.140.10; 91.140.65
English version
Thermal solar systems and components - Custom built systems
- Part 3: Performance characterisation of stores for solar heating
systems
Installations solaires thermiques et leur composants - Thermische Solaranlagen und ihre Bauteile -
Installations assemblées à façon - Partie 3: Caractérisation Kundenspezifisch gefertigte Anlagen - Teil 3:
des performances des dispositifs de stockage pour des Leistunsprüfung von Warmwasserspeichern für
installations de chauffage solaire Solaranlagen
This European Prestandard (ENV) was approved by CEN on 12 March 2001 as a prospective standard for provisional application.
The period of validity of this ENV is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the ENV can be converted into a European Standard.
CEN members are required to announce the existence of this ENV in the same way as for an EN and to make the ENV available promptly
at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the ENV) until the final
decision about the possible conversion of the ENV into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, 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
© 2001 CEN All rights of exploitation in any form and by any means reserved Ref. No. ENV 12977-3:2001 E
worldwide for CEN national Members.

Page 2
Contents
Page
Foreword . 3
Introduction. 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Symbols and abbreviations . 10
5 Store classification. 11
6 Laboratory store testing. 11
7 Store test combined with a system test according to ISO 9459-5 . 51
8 Test report . 51
Annex A (normative) Requirements for the numerical store model . 54
Annex B (normative) Store model benchmark tests . 56
Annex C (normative) Benchmarks for the parameter identification . 58
Bibliography. 60

Page 3
Foreword
This European Prestandard has been prepared by Technical Committee CEN/TC 312
"Thermal solar systems and components", the secretariat of which is held by ELOT.
According to the CEN/CENELEC Internal Regulations, the national standards
organizations of the following countries are bound to announce this European
Prestandard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany,
Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain,
Sweden, Switzerland and the United Kingdom.
The annexes A, B and C are normative.
Introduction
The test methods for stores of solar heating systems as described in this Prestandard
are required for the determination of the thermal performance of small custom built
systems as specified in ENV 12977-1.
These test methods deliver parameters, which are needed for the simulation of the
thermal behaviour of a store being part of a small custom built system.
NOTE 1 For additional information about the test methods for the performance characterization of
stores see
1 in Bibliography.
NOTE 2 With the test methods for stores given in prEN 12897:1997 only a few parameters are
determined in order to characterise the thermal behaviour of a store. These few parameters are not
sufficient for the determination of the thermal performance of small custom built systems as described in
ENV 12977-2.
This is due to the fact that the performance of thermal solar systems depends much more on the
thermal behaviour of the store (e. g. stratification, heat losses), as conventional systems do. Hence this
separate Prestandard for the performance characterisation of stores for solar heating systems is
needed.
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1 Scope
This Prestandard specifies test methods for the performance characterization of
stores which are intended for use in small custom built systems as specified in
ENV 12977-1.
Stores tested according to this Prestandard are commonly used in solar hot water
systems. However, also the thermal performance of all other thermal stores with water
as storage medium (e.g. for heat pump systems) can be assessed according to this
Prestandard.
The Prestandard applies to stores with a nominal volume between 50 and 3000 litres
and without integrated oil or gas burner.
2 Normative references
This European Prestandard incorporates, by dated or undated reference, provisions
from other publications. These normative references are cited at the appropriate
places in the text and the publications are listed hereafter. For dated references,
subsequent amendments to or revisions of any of these publications apply to this
European Prestandard only when incorporated in it by amendment or revision. For
undated references the latest edition of the publication referred to applies.
EN 12976-2:2000 Thermal solar systems and components - Factory made
systems - Test Methods
ENV 12977-2:2001 Thermal Solar Systems and Components – Custom Built
Systems – Test Methods
prEN 12828:1997 Heating systems in buildings – Design and installation of water
heating systems
prEN 12897:1997 Water supply – Specification for indirectly heated unvented
(closed) hot water storage systems
EN ISO 9488 Solar energy – Vocabulary (ISO 9488:1999)
ISO 9459-5 Solar heating – Domestic water heating systems – Part 5:
System performance characterization by means of whole –
system tests and computer simulation
3 Terms and definitions
For the purposes of this European Prestandard the following terms and definitions together
with EN ISO 9488 apply.
3.1
ambient temperature
mean value of the temperature of the air surrounding the store
3.2
charge
process of transferring energy into the store by means of an heat source

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3.3
charge connection
pipe connection used for charging the storage device
3.4
combistore
store used for both domestic hot water preparation and space heating
3.5
~

constant inlet temperature ( )
x,i
temperature which is achieved during charge (x=C) or discharge (x=D), if the mean
~

value over the period of 0,5 reduced charge / discharge volumes (see 3.34) is within
x,i
~
o
(  1) C

x,i
3.6
~


constant flow rate (V )
~


flow rate which is achieved, when the mean value V over the period of 0,5 reduced charge
~


/ discharge volumes (see 3.34) is within V 10 %
3.7
~
constant charge power (P )
C
charge power which is achieved, when the mean value P over the period of 0,5 reduced
C
~
charge volumes is within P  10 %
C
3.8
conditioning
process of creating a uniform temperature inside the store by
~
o
discharging the store with  = 20 C until a steady state is reached
D,i
NOTE The conditioning at the beginning of a test sequence is intended to provide a well defined
initial system state, i. e. an uniform temperature in the entire store.
3.9
discharge connection
pipe connection used for discharging the storage device
3.10
dead volume / dead capacity
the volume / capacity of the store which is only heated due to heat conduction (e. g.
below a heat exchanger)
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3.11
direct charge / discharge
transfer or removal of thermal energy in or out of the store, by directly exchanging the
fluid in the store
3.12
discharge
process of decreasing thermal energy inside the store caused by the hot water load
3.13
double port
a corresponding pair of inlet and outlet connections for direct charge / discharge of the
store
NOTE Often, the store is charged or discharged via closed or open loops that are
connected to the store through double ports.
3.14
effective volume / effective capacity
the volume / capacity which is involved in the heat storing process if the store is
operated in a usual way
3.15
electrical (auxiliary) heating
electrical heating element immersed into the store
3.16
external auxiliary heating
auxiliary heating device located outside the store. The heat is transferred to the store
by direct or indirect charging via a charge loop. The external auxiliary heating is not
considered as part of the store under test
3.17
( )
heat loss capacity rate UA
s,a
the overall heat loss of the entire storage device per K temperature difference
between the store temperature and the ambient air temperature
NOTE The heat loss capacity rate depends on the flow conditions inside the store. Hence a
stand-by heat loss capacity rate and a operating heat loss capacity rate are defined. If (UA) is
s,a
mentioned without specification, (UA) represents the stand-by heat loss capacity rate.
s,a
3.18
heat transfer capacity rate
the thermal power transferred per K temperature difference

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3.19
immersed heat exchanger
heat exchanger which is completely surrounded with the fluid in the store tank
3.20
indirect charge / discharge
transfer or removal of thermal energy into or out of the store, via a heat exchanger
3.21
load
the heat output of the store during discharge. The load is defined as the product of the
mass, specific thermal capacity and temperature increase of the water as it passes
the solar hot water system
3.22
mantle heat exchanger
heat exchanger mounted to the store in a way, that it forms a layer between the fluid
in the store tank and ambient
3.23
measured store heat capacity
the measured difference in energy of the store between two steady states on different
temperature levels, divided by the temperature difference between this two steady
states
3.24
measured energy (Q )
x,m
time integral of the measured power over one or more test sequences, excluding time
periods used for conditioning at the beginning of the test sequences
3.25
measured power (P )
x,m
power calculated from measured volume flow rate as well as measured inlet and outlet
temperature
3.26
mixed
state when the local store temperature is not a function of the vertical store height
3.27
model parameter
parameter used for quantification of a physical effect, if this physical effect is
implemented in a mathematical model in a way which is not analogous to its

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appearance in reality, or if several physical effects are lumped in the model (e. g. a
stratification number)
3.28


nominal flow rate ( V )
n
the nominal volume of the entire store divided by 1 h
3.29
nominal heating power (P )
n
the nominal volume of the entire store multiplied by 10 W/l
3.30
nominal volume (V )
n
fluid volume of the store as specified by the manufacturer
3.31
operating heat loss capacity rate (UA)
op,s,a
heat loss capacity rate of the store during charge or discharge
3.32
predicted energy (Q )
x,p
time integral of the predicted power over one or more test sequences, excluding time
periods used for conditioning at the beginning of the test sequences
3.33
predicted power (P )
x,p
power calculated from measured volume flow rate, as well as measured inlet
temperature and calculated outlet temperature. The outlet temperature is predicted by
numerical simulation
3.34
reduced charge / discharge volume
integral of a charge / discharge flow rate divided by the store volume
3.35
stand-by
state of operation in which no energy is deliberately transferred to or removed from the
store
3.36
stand-by heat loss capacity rate (UA)
sb,s,a
heat loss capacity rate of the store during stand-by

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3.37
steady state
state of operation at which at charge or discharge during 0,5 reduced charge /
discharge volume (see 3.34) the standard deviation of the temperature difference,
between store inlet and store outlet temperature of the charging / discharging circuit is
lower than 0,05 K
NOTE In cases of an isothermal charged store rather constant temperature differe
...