SIST EN 12977-3:2008
(Main)Thermal solar systems and components - Custom built systems - Part 3: Performance test methods for solar water heater stores
Thermal solar systems and components - Custom built systems - Part 3: Performance test methods for solar water heater stores
This European Standard specifies test methods for the performance characterization of stores which are intended for use in small custom built systems as specified in prCEN/TS 12977-1.
Stores tested according to this document are commonly used in solar hot water systems. However, also the thermal performance of all other thermal stores with water as storage medium can be assessed according to the test methods specified in this document.
The document applies to stores with a nominal volume between 50 l and 3 000 l.
This document does not apply to combistores. Performance test methods for solar combistores are specified in prCEN/TS 12977-4.
Thermische Solaranlagen und ihre Bauteile - Kundenspezifisch gefertigte Anlagen - Teil 3: Leistungsprüfung von Warmwasserspeichern für Solaranlagen
Diese Europäische Norm legt Verfahren zur Leistungsprüfung von Warmwasserspeichern (im Folgenden Speicher genannt) fest, die zur Verwendung in kleinen kundenspezifisch gefertigten Solaranlagen nach prCEN/TS 12977 1 bestimmt sind.
Speicher, die nach diesem Dokument geprüft sind, werden im Allgemeinen in solaren Warmwasseranlagen verwendet. Die Wärmeleistung aller anderen Warmwasserspeicher kann jedoch auch nach den Prüfverfahren dieses Dokuments bewertet werden.
Dieses Dokument gilt für Speicher mit einem Nennvolumen zwischen 50 l und 3000 l.
Dieses Dokument gilt nicht für Kombi Speicher. Die Verfahren zur Leistungsprüfung von Solar Kombi Speichern sind in prCEN/TS 12977 4 festgelegt.
Installations solaires thermiques et leurs composants - Installations assemblées à façon - Partie 3: Méthodes d'essai des performances des dispositifs de stockage des installations de chauffage solaire de l'eau
La présente Norme européenne spécifie des méthodes d'essai pour la caractérisation des performances des
dispositifs de stockage destinés à être utilisés dans de petites installations assemblées à façon, comme
spécifié dans la prCEN/TS 12977-1.
Les dispositifs de stockage soumis à essai conformément au présent document sont couramment utilisés
dans les installations solaires de production d'eau chaude. Toutefois, les performances thermiques de tous
les autres dispositifs de stockage thermique où l’eau est utilisée comme milieu de stockage peuvent
également être évaluées conformément aux méthodes d’essai spécifiées dans le présent document.
Le document s’applique aux dispositifs de stockage dont le volume nominal est compris entre 50 l et 3 000 l.
Le présent document ne s’applique pas aux dispositifs de stockage mixtes. Les méthodes d’essai relatives
aux performances des dispositifs de stockage solaires mixtes sont spécifiées dans la prCEN/TS 12977-4.
Toplotni sončni sistemi in sestavni deli - Neserijsko izdelani sistemi - 3. del: Določanje preskusnih metod za hranilnike toplote, ogrevane s soncem
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.HPThermische Solaranlagen und ihre Bauteile - Kundenspezifisch gefertigte Anlagen - Teil 3: Leistungsprüfung von Warmwasserspeichern für SolaranlagenInstallations solaires thermiques et leurs composants - Installations assemblées à façon - Partie 3: Méthodes d'essai des performances des dispositifs de stockage des installations de chauffage solaire de l'eauThermal solar systems and components - Custom built systems - Part 3: Performance test methods for solar water heater stores91.140.65Oprema za ogrevanje vodeWater heating equipment91.140.10Sistemi centralnega ogrevanjaCentral heating systems27.160Solar energy engineeringICS:Ta slovenski standard je istoveten z:EN 12977-3:2008SIST EN 12977-3:2008en,fr,de01-november-2008SIST EN 12977-3:2008SLOVENSKI
STANDARDSIST ENV 12977-3:20021DGRPHãþD
SIST EN 12977-3:2008
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 12977-3August 2008ICS 91.140.10; 91.140.65; 27.160Supersedes ENV 12977-3:2001
English VersionThermal solar systems and components - Custom built systems- Part 3: Performance test methods for solar water heater storesInstallations solaires thermiques et leurs composants -Installations assemblées à façon - Partie 3: Méthodesd'essai des performances des dispositifs de stockage desinstallations de chauffage solaire de l'eauThermische Solaranlagen und ihre Bauteile -Kundenspezifisch gefertigte Anlagen - Teil 3:Leistungsprüfung von Warmwasserspeichern fürSolaranlagenThis European Standard was approved by CEN on 15 May 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2008 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12977-3:2008: ESIST EN 12977-3:2008
EN 12977-3:2008 (E) 2 Contents Page Foreword.4 Introduction.5 1 Scope.6 2 Normative references.6 3 Terms and definitions.6 4 Symbols and abbreviations.10 5 Store classification.11 6 Laboratory store testing.12 6.1 Requirements on the testing stand.12 6.1.1 General.12 6.1.2 Measured quantities and measuring procedure.15 6.2 Installation of the store.15 6.2.1 Mounting.15 6.2.2 Connection.16 6.3 Test and evaluation procedures.16 6.3.1 General.16 6.3.2 Test sequences.17 6.3.3 Data processing of the test sequences.28 7 Store test combined with a system test according to ISO 9459-5.30 8 Store test according to EN 12897.30 9 Test report.30 9.1 General.30 9.2 Description of the store.30 9.3 Test results.31 9.4 Parameters for the simulation.32 Annex A (normative)
Store model benchmark tests.33 A.1 General.33 A.2 Temperature of the store during stand-by.33 A.3 Heat transfer from heat exchanger to store.33 Annex B (normative)
Verification of store test results.35 B.1 General.35 B.2 Test sequences for verification of store test results.35 B.2.1 Verification sequences from measurements on a store testing stand.35 B.2.2 Test sequences obtained during a whole system test according to ISO 9459-5.42 B.3 Verification procedure.42 B.3.1 General.42 B.3.2 Error in transferred energies.42 B.3.3 Error in transferred power.43 Annex C (normative)
Benchmarks for the parameter identification.44 Annex D (informative)
Requirements for the numerical store model.45 D.1 General.45 D.2 Assumptions.45 D.3 Calculation of energy balance.45 SIST EN 12977-3:2008
EN 12977-3:2008 (E) 3 Annex E (informative)
Determination of store parameters by means of “up-scaling” and
“down-scaling”.47 E.1 General.47 E.2 Requirements.47 E.3 Determination of store parameters.48 E.3.1 Thermal capacity of store.48 E.3.2 Height of store.48 E.3.3 Determination of heat loss capacity rate.48 E.3.4 Relative heights of the connections and the temperature sensors.48 E.3.5 Heat exchangers.48 E.3.6 Parameter describing the degradation of thermal stratification during stand-by.49 E.3.7 Parameter describing the quality of thermal stratification during direct discharge.49 Annex F (informative)
Determination of hot water comfort.50 Bibliography.51
SIST EN 12977-3:2008
EN 12977-3:2008 (E) 4 Foreword This document (EN 12977-3:2008) has been prepared by Technical Committee CEN/TC 312 “Thermal solar systems and components”, the secretariat of which is held by ELOT. 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 February 2009, and conflicting national standards shall be withdrawn at the latest by February 2009. 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 ENV 12977-3:2001. "Thermal solar systems and components — Custom built systems" consists of the following parts: prCEN/TS 12977-1: General requirements for solar water heaters and combisystems
prCEN/TS 12977-2: Test methods
EN 12977-3: Performance test methods for solar water heater stores
prCEN/TS 12977-4:
Performance test methods for solar combistores
prCEN/TS 12977-5:
Performance test methods for control equipment
NOTE The “prCEN/TS” standards are expected to become CEN/TS standards in the future. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 12977-3:2008
EN 12977-3:2008 (E) 5
Introduction The test methods for stores of solar heating systems as described in this European Standard are required for the determination of the thermal performance of small custom built systems as specified in prCEN/TS 12977-1. The test method described in this European Standard delivers a complete set of parameters, which are needed for the simulation of the thermal behaviour of a store being part of a small custom built thermal solar system. For the determination of store parameters such as the thermal capacity and the heat loss rate the method standardised in EN 12897 can be used as an alternative. NOTE 1 The already existing test methods for stores of conventional heating systems are not sufficient with regard to thermal solar systems. 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), than conventional systems do. Hence this separate document for the performance characterisation of stores for solar heating systems is needed. NOTE 2 For additional information about the test methods for the performance characterisation of stores, see [1] in Bibliography.
SIST EN 12977-3:2008
EN 12977-3:2008 (E) 6
1 Scope This European Standard specifies test methods for the performance characterization of stores which are intended for use in small custom built systems as specified in prCEN/TS 12977-1.
Stores tested according to this document are commonly used in solar hot water systems. However, also the thermal performance of all other thermal stores with water as storage medium can be assessed according to the test methods specified in this document. The document applies to stores with a nominal volume between 50 l and 3 000 l. This document does not apply to combistores. Performance test methods for solar combistores are specified in prCEN/TS 12977-4.
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 12828, Heating systems in buildings — Design for water-based heating systems EN 12897, Water supply – Specification for indirectly heated unvented (closed) storage water heaters EN ISO 9488:1999, 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 document, the terms and definitions given in EN ISO 9488:1999 and the following 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 a heat source 3.3 charge connection pipe connection used for charging the storage device 3.4 combistore one store used for both domestic hot water preparation and space heating SIST EN 12977-3:2008
EN 12977-3:2008 (E) 7 3.5 constant inlet temperature, x,i~ϑ temperature which is achieved during charge (x = C) or discharge (x = D), if the mean value x,i~ϑ over the period of 0,5 “reduced charge/discharge volume” (see 3.34) is within (x,i~ϑ ± 1) °C NOTE The symbol ”~” above a certain value indicates that the corresponding value is a mean value.
3.6 constant flow rate, V~&
flow rate which is achieved when the mean value of V~& over the period of 0,5 “reduced charge/discharge volumes” (see 3.34) is within V~&± V~& • 0,1 NOTE The symbol ”~” above a certain value indicates that the corresponding value is a mean value.
3.7 constant charge power, c~P charge power which is achieved when the mean value c~P over the period of 0,5 reduced charge volumes is within
c~P ± c~P • 0,1 NOTE The symbol ”~” above a certain value indicates that the corresponding value is a mean value.
3.8 conditioning process of creating a uniform temperature inside the store by discharging the store with D,i~ϑ = 20 °C until a steady state is reached NOTE The conditioning at the beginning of a test sequence is intended to provide a well-defined initial system state, i. e. a uniform temperature in the entire store. 3.9 discharge connection pipe connection used for discharging the storage device 3.10 dead volume/dead capacity volume/capacity of the store which is only heated due to heat conduction (e.g. below a heat exchanger) 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 SIST EN 12977-3:2008
EN 12977-3:2008 (E) 8 3.13 double port 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 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 overall heat loss of the entire storage device per K of the 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 an operating heat loss capacity rate are defined. If (UA)s,a is mentioned without specification, (UA)s,a represents the stand-by heat loss capacity rate. 3.18 heat transfer capacity rate thermal power transferred per K of the temperature difference 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 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 such a way that it forms a layer between the fluid in the store tank and ambient 3.23 measured store heat capacity measured difference in energy of the store between two steady states on different temperature levels, divided by the temperature difference between these two steady states SIST EN 12977-3:2008
EN 12977-3:2008 (E) 9 3.24 measured energy, Qx,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, Px,m power calculated from measured volume flow rate as well as measured inlet and outlet temperatures 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 appearance in reality, or if several physical effects are lumped in the model (e.g. a stratification number) 3.28 nominal flow rate, nV& nominal volume of the entire store divided by 1 h 3.29 nominal heating power, Pn nominal volume of the entire store multiplied by 10 W/l 3.30 nominal volume, Vn 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, Qxp 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, Pxp power calculated from measured volume flow rate, as well as measured inlet temperature and calculated outlet temperature NOTE 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 SIST EN 12977-3:2008
EN 12977-3:2008 (E) 10 3.36 stand-by heat loss capacity rate, (UA)sb,s,a heat loss capacity rate of the store during stand-by 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 temperatures of the charging/discharging circuit is lower than 0,1 K NOTE In cases of an isothermal charged store, constant temperature differences between the inlet and outlet temperatures of the discharge circuit may occur during the discharge of the first store volume before the outlet temperature drops rapidly. This state is not considered as steady state. 3.38 store temperature temperature of the store medium 3.39 stratified state when thermal stratification is present inside the store 3.40 stratified charging increase of thermal stratification in the store during charging 3.41 stratifier device that enables stratified charging of the store. Commonly used stratifiers are e.g. convection chimneys or pipes with radial holes 3.42 theoretical store heat capacity sum over all thermal capacities mi × cp,i of the entire store (fluid, tank material, heat exchangers) having part of the heat store process 3.43 thermal stratification state when the local store temperature is a function of the vertical store height, with the temperature decreasing from top to bottom 3.44 transfer time, tx,f time period during which energy is transferred through the connections for charge (x = C) or discharge (x = D). The transfer time is calculated over one or more test sequences, excluding time periods used for conditioning at the beginning of the test sequences 4 Symbols and abbreviations
Cs thermal capacity of the entire store, in J/K cp specific heat capacity, in J/(kg K) Pn nominal heating power, in W Px,m measured power transferred through the charge (x = C) or discharge (x = D) circuit, in W SIST EN 12977-3:2008
EN 12977-3:2008 (E) 11 Px,p predicted power transferred through the charge (x = C) or discharge (x = D) circuit, in W Qx,m measured energy transferred through the charge (x = C) or discharge (x = D) circuit, in J Qx,p predicted energy transferred through the charge (x = C) or discharge (x = D) circuit, in J tst time required to achieve a steady state, in s tx,f transfer time for charging (x = C) or discharging (x = D), in s ϑa ambient temperature, in °C ϑs store temperature, in °C ϑx,i inlet temperature of the charge (x = C) or discharge (x = D) circuit, in °C x,i~ϑ constant inlet temperature of the charge (x = C) or discharge (x = D) circuit, in °C ϑx,o outlet temperature of the charge (x = C) or discharge (x = D) circuit, in °C (UA)hx,s heat transfer capacity rate between heat exchanger and store, in W/K (UA)s,a heat loss capacity rate of the store, in W/K (UA)op,s,a operating heat loss capacity rate of the store, in W/K (UA)sb,s,a stand-by heat loss capacity rate of the store, in W/K Vn nominal volume of the store, in l nV& nominal flow rate, in l/h x~V& constant flow rate of the charge (x = C) or discharge (x = D) circuit, in l/h ∆ϑm mean logarithmic temperature difference, in K εx,P
relative error in mean power transferred during charge (x = C) or discharge (x = D), in % εx,Q
relative error in energy transferred during charge (x = C) or discharge (x = D), in % ρ density, in kg/m³ 5 Store classification Hot water stores are classified by distinction between different charge and discharge modes. Five groups are defined as shown in Table 1. SIST EN 12977-3:2008
EN 12977-3:2008 (E) 12
Table 1 — Classification of the stores Group Charge mode Discharge mode 1 direct direct 2 indirect direct 3 direct indirect 4 indirect indirect 5 stores that cannot be assigned to groups 1 to 4
NOTE 1 All stores may have one or more additional electrical heating elements. 6 Laboratory store testing 6.1 Requirements on the testing stand 6.1.1 General The hot water store shall be tested separately from the whole solar system on a store testing stand. The testing stand configuration shall be determined by the classification of hot water stores as described in Clause 5. An example of a representative hydraulic testing stand configuration is shown in Figure 1 and Figure 2.
The circuits are intended to simulate the charge and discharge loop of the solar system and to provide fluid flow with a constant or well controlled temperature. The full test stand consists of one charge and one discharge circuit. NOTE 1 If the store consists of more than one charge or discharge devices (e.g. two heat exchangers), then these are tested separately. The testing stand shall be located in an air-conditioned room where the room temperature of 20 °C should not vary more than ± 2 K during the test. Both circuits shall fulfil the following requirements: the flow rate shall be adjustable and stable within
±5 %; the working temperature range shall be between 10 °C and 90 °C; NOTE 2 A typical heating power of the charge circuit is in the range of 15 kW. the minimum cooling power in the discharge circuit shall be at least 25 kW at a fluid temperature of 20 °C; NOTE 3 A typical heating power of the discharge circuit is in the range of 25 kW. NOTE 4 If mains water at a constant pressure and a constant temperature below 20 °C is available, it is recommended to design the discharge circuit in a way, that it can be operated as closed loop or as open loop using mains water to discharge the store.
SIST EN 12977-3:2008
EN 12977-3:2008 (E) 13 the minimum heating up rate of the charge circuit with disconnected store shall be 3 K/min; the minimum available electrical heating power for electrical auxiliary heaters shall be 6,0 kW.
NOTE 5 The electrical power of the pump (P102) should be chosen in such a way that the temperature increase induced by the pump (P102) is either less than 0,6 K/h when the charge circuit is "short-circuited" and operated at room temperature (“short-circuited” means that no storage device is connected and SV102, V113, V115 and V116 are closed, see Figure 1) or an additional cooling device should be integrated in the circuit.
Key FF Flow meter HX Heat exchanger OP Overheating protection P Pump ST Store (belonging to test facility)
SV Solenoid valve TT Temperature sensor TIC Temperature indicator and controller V Valve Figure 1 — Charge circuit of the store testing stand The heating medium water in the charge circuit (see Figure 1) is pumped through the cooler (HX101) and the temperature controlled heaters (TIC106) by the pump (P101). A buffer tank (ST101) is used to balance the remaining control deviations. By means of the bypass (V107) the flow through the store can be controlled, it also ensures a continuously high flow through the heating section and therefore good control characteristics. With the solenoid valve (SV101) the heating medium can bypass the store to prepare a sudden increase of the inlet temperature into the store. The temperature sensors are placed near the inlet (TT101) and outlet (TT102) connections of the store; the connection to the store is established through insulated flexible pipes.
The charge circuit can be operated closed, under pressure (design pressure 2,5 bar, membrane pressure expansion tank and pressure relief valve (V109)) as well as open (valve (V108) open) with the tank (ST102) SIST EN 12977-3:2008
EN 12977-3:2008 (E) 14 serving as an expansion tank. A calibration of the installed flow meter (FF105) is possible by weighing the mass of water leaving the valve (V112). The installation is equipped with the usual safety devices, i.e. pressure relief valve (V117) and overheating protection device (OP101). The discharge circuit (see Figure 2) is constructed in a similar way. It includes two coolers – (HX201) and (HX202) – and a temperature controlled heating element (TIC206) with 5 kW heating power. The discharge circuit can either be operated in open circulation with water from the net or it can be operated in closed circulation. During open operation the water is led via the safety equipment (V201) and flows through the coolers, the heating section and the flow meter (FF205) into the store. The hot water leaving the store flows through the solenoid valve (SV201) and the valve (V210) into the drain. The valve (V212) is closed. For heating the water it is recommended to increase the flow through the heating section with the pump (P201) in order to improve the control performance; the additional volume flow
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