SIST EN 12977-2:2012
(Main)Thermal solar systems and components - Custom built systems - Part 2: Test methods for solar water heaters and combisystems
Thermal solar systems and components - Custom built systems - Part 2: Test methods for solar water heaters and combisystems
This European Standard applies to small and large custom built solar heating systems with liquid heat transfer medium for residential buildings and similar applications, and gives test methods for verification of the requirements specified in FprEN 12977 1.
This document also includes a method for thermal performance characterization and system performance prediction of small custom built systems by means of component testing and system simulation.
Furthermore, this document contains methods for thermal performance characterization and system performance prediction of large custom built systems.
This document applies to the following types of small custom built solar heating systems:
- systems for domestic hot water preparation only;
- systems for space heating only;
- systems for domestic hot water preparation and space heating;
- others (e.g. including cooling).
This document applies to large custom built solar heating systems, primarily to solar preheat systems, with one or more storage vessels, heat exchangers, piping and automatic controls and with collector array(s) with forced circulation of fluid in the collector loop.
This document does not apply to
- systems with a store medium other than water (e.g. phase change materials),
- thermosiphon systems,
- integral collector storage (ICS) systems.
Thermische Solaranlagen und ihre Bauteile - Kundenspezifisch gefertigte Anlagen - Teil 2: Prüfverfahren für solar betriebene Warmwasserbereiter und Kombinationssysteme
Diese Europäische Norm gilt für kleine und große kundenspezifisch gefertigte thermische Solaranlagen mit flüssigem Wärmeträgermedium, die für den Einsatz in Wohnbauten und ähnliche Anwendungsfälle vorgese-hen sind, und gibt Prüfverfahren für die Verifizierung der Erfüllung der in FprEN 12977 1 festgelegten Anfor-derungen an.
Dieses Dokument enthält auch ein Verfahren für die Charakterisierung der Wärmeleistung und die Vorhersage der zu erwartenden Anlagenleistung kleiner kundenspezifisch gefertigter Anlagen durch Bauteilprüfung und Anlagensimulation.
Darüber hinaus enthält dieses Dokument Verfahren für die Charakterisierung der Wärmeleistung und die Vorhersage der zu erwartenden Anlagenleistung großer kundenspezifisch gefertigter Anlagen.
Dieses Dokument gilt für die folgenden Typen kleiner kundenspezifisch gefertigter thermischer Solaranlagen:
- ausschließlich für die häusliche Warmwasserbereitung verwendete Anlagen;
- ausschließlich für die Raumheizung verwendete Anlagen;
- für häusliche Warmwasserbereitung und Raumheizung verwendete Anlagen;
- sonstige Anlagen (z. B. einschließlich Kühlung).
Dieses Dokument gilt für große kundenspezifisch gefertigte thermische Solaranlagen, hauptsächlich für solare Vorwärmanlagen mit einem oder mehreren Speichern, Wärmeaustauschern, Rohrleitungen und automati¬schen Reglern und einer oder mehreren Kollektorgruppen mit erzwungener Umwälzung des Fluids im Kollek¬torkreislauf.
Dieses Dokument gilt nicht für
- Anlagen, die ein anderes Speichermedium als Wasser verwenden (z. B. Material für Phasenumwand¬lung),
- Thermosiphon-Anlagen,
- integrierte Kollektor-Speicher(ICS)-Anlagen.
Installations solaires thermiques et leurs composants - Installations assemblées à façon - Partie 2: Méthodes d'essai pour chauffe-eau solaires et installations solaires combinées
La présente Norme européenne s’applique aux petites et grandes installations de chauffage solaire
assemblées à façon, à liquide caloporteur, utilisées dans les bâtiments résidentiels et applications similaires,
et il présente des méthodes d’essai permettant de vérifier les exigences spécifiées dans le EN 12977-1.
Le présent document comprend également une méthode de caractérisation des performances thermiques et
de prévision des performances des petites installations assemblées à façon à l’aide d’essais des composants
et de simulation de l’installation.
Par ailleurs, le présent document contient des méthodes pour la caractérisation des performances thermiques
et la prévision des performances des grandes installations assemblées à façon.
Le présent document s’applique aux types suivants de petites installations de chauffage solaire assemblées à
façon :
- installations pour la production d’eau chaude sanitaire exclusivement ;
- installations pour le chauffage des locaux uniquement ;
- installations pour la production d’eau chaude sanitaire et le chauffage des locaux ;
- autres (par exemple, y compris le refroidissement).
Le présent document s’applique aux grandes installations de chauffage solaire assemblées à façon,
principalement aux installations à préchauffage, munies d’une ou de plusieurs cuves de stockage, échangeurs
de chaleur, canalisations et dispositifs de régulation automatique, et d’un ou de plusieurs champs de capteurs
à circulation forcée de fluide dans la boucle de captage.
Le présent document ne s’applique pas aux :
- installations ayant un autre milieu de stockage que l’eau (par exemple, matériaux à changement de
phase) ;
- installations à thermosiphon ;
- installations à capteurs autostockeurs (ICS).
Toplotni sončni sistemi in sestavni deli - Neserijsko izdelani sistemi - 2. del: Preskusne metode za sončne grelnike vode in kombinirane sisteme
Ta evropski standard se uporablja za majhne in velike neserijsko izdelane sončne ogrevalne sisteme s tekočim sredstvom za prenos toplote za stanovanjske zgradbe in podobne uporabe ter določa preskusne metode za preverjanje zahtev iz standarda FprEN 12977-1. Dokument vsebuje tudi metodo za definicijo toplotne učinkovitosti in predvidevanje sistemske učinkovitosti majhnih neserijsko izdelanih sistemov s pomočjo preskušanja sestavnih delov in simulacije sistema. Poleg tega dokument vsebuje metode za definicijo toplotne učinkovitosti in predvidevanje sistemske učinkovitosti velikih neserijsko izdelanih sistemov. Ta dokument se uporablja za naslednje vrste majhnih neserijsko izdelanih sončnih ogrevalnih sistemov: sisteme za pripravo tople vode v gospodinjstvih, sisteme, namenjene le za segrevanje prostorov, sisteme za pripravo tople vode v gospodinjstvih in segrevanje prostorov ter druge sisteme (npr. vključno s hlajenjem). Ta dokument se uporablja za velike neserijsko izdelane sončne ogrevalne sisteme, predvsem za sončne predogrevalne sisteme, z eno ali več posodami za shranjevanje, toplotnimi prenosniki, ocevjem in samodejnim krmiljenjem ter kolektorskimi polji s prisilnim kroženjem tekočine v zanki kolektorja. Ta dokument se ne uporablja za sisteme, ki kot sredstvo shranjevanja uporabljajo druga sredstva namesto vode (npr. fazno spremenljive materiale), termosifonske sisteme in sisteme integralnega kolektorskega shranjevanja (ICS).
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Thermische Solaranlagen und ihre Bauteile - Kundenspezifisch gefertigte Anlagen - Teil 2: Prüfverfahren für solar betriebene Warmwasserbereiter und KombinationssystemeInstallations solaires thermiques et leurs composants - Installations assemblées à façon -
Partie 2: Méthodes d'essai pour chauffe-eau solaires et installations solaires combinéesThermal solar systems and components - Custom built systems - Part 2: Test methods for solar water heaters and combisystems91.140.65Oprema za ogrevanje vodeWater heating equipment91.140.10Sistemi centralnega ogrevanjaCentral heating systems27.160Solar energy engineeringICS:Ta slovenski standard je istoveten z:EN 12977-2:2012SIST EN 12977-2:2012en,fr,de01-julij-2012SIST EN 12977-2:2012SLOVENSKI
STANDARDSIST-TS CEN/TS 12977-2:20101DGRPHãþD
SIST EN 12977-2:2012
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 12977-2
April 2012 ICS 27.160 Supersedes CEN/TS 12977-2:2010English Version
Thermal solar systems and components - Custom built systems - Part 2: Test methods for solar water heaters and combisystems
Installations solaires thermiques et leurs composants - Installations assemblées à façon - Partie 2: Méthodes d'essai pour chauffe-eau solaires et installations solaires combinées
Thermische Solaranlagen und ihre Bauteile - Kundenspezifisch gefertigte Anlagen - Teil 2: Prüfverfahren für solar betriebene Warmwasserbereiter und Kombinationssysteme This European Standard was approved by CEN on 19 February 2012.
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 CEN-CENELEC 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 translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, 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, Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12977-2:2012: ESIST EN 12977-2:2012
EN 12977-2:2012 (E) 2 Contents Page Foreword .4Introduction .51Scope .82Normative references .83Terms and definitions .94Symbols and abbreviations . 105System classification . 126Test methods . 126.1Introduction . 126.2General . 126.3Materials . 136.4Components and pipework . 136.5Safety equipment and indicators . 156.6Installation . 166.7Initial operation, inspection and commissioning . 166.8Documentation . 176.9System performance (for small systems only) . 176.10Water wastage (for small systems only) . 177Optional performance test of small custom built solar heating systems . 177.1General . 177.2Test of the solar collector . 187.3Test of the water store(s) . 187.4Test of the control equipment . 187.5Determination of the hot water comfort . 187.6System simulation model . 197.7Long-term performance prediction . 197.8Presentation of performance indicators . 258Performance test report . 26Annex A (normative)
Reference conditions for performance prediction . 28A.1General . 28A.2Pipe diameter and insulation thickness . 30A.3Calculation of mains water temperature at reference location . 30A.4Space heating load . 31Annex B (normative)
Additional information regarding the calculation of the fractional energy savings . 37B.1Definition of a conventional reference water heating system . 37B.2Calculation of fractional energy savings for other conditions . 37Annex C (informative)
Short-term system testing . 39C.1General . 39C.2Instrumentation, data acquisition and processing . 39C.3Check of short-term system performance . 41C.4Short-term test for long-term system performance prediction . 44Annex D (informative)
Long-term monitoring . 51D.1General . 51D.2Evaluation chart . 52SIST EN 12977-2:2012
EN 12977-2:2012 (E) 3 D.3Monitoring equipment . 52D.4Data analysis . 52Annex E (informative)
Determination of water wastage . 53Bibliography . 54 Figures Figure 1 — Energy balance for one-store and two-store solar-plus-supplementary systems . 21Figure 2 — Comparison of the gross auxiliary energy demand of the solar heating system, Qaux, to the gross energy demand of the conventional heating system, Qconv . 22Figure 3 — Energy balance for solar only systems . 24Figure 4 — Energy balance for solar preheat systems . 25Figure C.1 — Principle of the short term system performance check: Check and intercomparison of useful energy gain . 41Figure C.2 — Principle of the short-term test and of the subsequent long term system performance prediction . 45Figure C.3 — Example of the predicted performance dependence on load level and irradiation for a solar domestic hot water heating system (see [8]) . 50 Tables Table 1 — Division for factory made and custom built solar heating systems . 6Table 2 — Symbols, definition and unit (1 of 2) . 10Table 2 — Symbols, definition and unit (2 of 2) . 11Table 3 — Presentation of system performance indicators for solar-plus-supplementary systems . 26Table 4 — Presentation of system performance indicators for solar-only and solar preheat systems . 26Table A.1 — Reference conditions for performance presentation (1 of 2) . 28Table A.1 — Reference conditions for performance presentation (2 of 2) . 29Table A.2 — External pipe diameter and insulation thickness for forced-circulation systems . 30Table A.3 — Data for calculation of the mains water temperature at the reference locations . 31Table A.4 — Space heating load file for Stockholm. 32Table A.5 — Space heating load file for Davos . 33Table A.6 — Space heating load file for Würzburg (1 of 2) . 34Table A.6 — Space heating load file for Würzburg (2 of 2) . 35Table A.7 — Space heating load file for Athens – Example to be updated . 36Table C.1 — Variables to be measured and corresponding maximum sampling intervals . 43Table C.2 — Variables to be measured during system test, and corresponding maximum sampling intervals . 46Table C.3 — Range of variations of the driving variables to be scanned during a test outdoors . 47Table C.4 — Permissible standard deviation for secondary collector parameters . 49 SIST EN 12977-2:2012
EN 12977-2:2012 (E) 4 Foreword This document (EN 12977-2:2012) 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 October 2012, and conflicting national standards shall be withdrawn at the latest by October 2012. 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 CEN/TS 12977-2:2010. 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, Croatia, 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, Turkey and the United Kingdom. SIST EN 12977-2:2012
EN 12977-2:2012 (E) 5 Introduction a) Drinking water quality In respect of potential adverse effects on the quality of drinking water intended for human consumption caused by the product covered by this document, it should be noted that 1) this document provides no information as to whether the product may be used without restriction in any of the Member States of the EU or EFTA, 2) while awaiting the adoption of verifiable European criteria, existing national regulations concerning the use and/or the characteristics of this product remain in force. b) Factory made and custom built solar heating systems EN 12976-1, EN 12976-2, EN 12977-1, EN 12977-2, EN 12977-3, EN 12977-4 and EN 12977-5 distinguish two categories of solar heating systems: 1) factory made solar heating systems; and 2) custom built solar heating systems. The classification of a system as factory made or custom built is a choice of the final supplier, in accordance to the following definitions. 1) Factory made solar heating systems are batch products with one trade name, sold as complete and ready to install kits, with fixed configurations. Systems of this category are considered as a single product and assessed as a whole. If a factory made solar heating system is modified by changing its configuration or by changing one or more of its components, the modified system is considered as a new system. Requirements and test methods for factory made solar heating systems are given in EN 12976-1 and EN 12976-2. 2) Custom built solar heating systems are either uniquely built or assembled by choosing from an assortment of components. Systems of this category are regarded as a set of components. The components are separately tested and test results are integrated to an assessment of the whole system. Requirements for custom built solar heating systems are given in EN 12977-1, test methods are specified in EN 12977-2, EN 12977-3, EN 12977-4 and EN 12977-5. Custom built solar heating systems are subdivided into two categories: i) large custom built systems are uniquely designed for a specific situation. In general, they are designed by HVAC engineers, manufacturers or other experts; ii) small custom built systems offered by a company are described in a so-called assortment file, in which all components and possible system configurations, marketed by the company, are specified. Each possible combination of a system configuration with components from the assortment is considered as one custom built system. Table 1 shows the division for different system types. SIST EN 12977-2:2012
EN 12977-2:2012 (E) 6 Table 1 — Division for factory made and custom built solar heating systems Factory made solar heating systems (EN 12976-1 and EN 12976-2) Custom built solar heating systems (EN 12977-1, EN 12977-2, EN 12977-3, EN 12977-4 and EN 12977-5) Integral collector-storage systems for domestic hot water preparation Forced circulation systems for hot water preparation and/or space heating/cooling, assembled using components and configurations described in a documentation file (mostly small systems) Thermosiphon systems for domestic hot water preparation Forced circulation systems as batch product with fixed configuration for domestic hot water preparation Uniquely designed and assembled systems for hot water preparation and/or space heating/cooling (mostly large systems)
NOTE 1 Forced circulation systems can be classified either as factory made or as custom built, depending on the market approach chosen by the final supplier. NOTE 2 Both factory made and custom built systems are performance tested under the same set of basic reference conditions as specified in EN 12976-2:2006, Annex B and in EN 12977-2:2012, Annex A. In practice, the installation conditions may differ from these reference conditions. c) Test methods and procedures for the analysis of large custom built solar heating systems Quality assurance is of primary importance for large custom built systems. The total investment cost for such systems is higher than for smaller ones, although the specific investment cost (i.e., per m² collector area) is lower. In several European countries, the potential of large custom built systems from the point of view of conventional energy savings is much larger than for smaller ones. Moreover, the return on investment is in many cases more favourable for large systems than for small ones. Hence, both the purchasers of large custom built systems and the governments are interested in efficient, reliable and durable systems, the thermal performance of which may be accurately predicted, checked and supervised. The test methods in this document provide a means of verifying the compliance of large custom built systems with the requirements in EN 12977-1. NOTE 3 Within the framework of the EU ALTENER Programme the project "Guaranteed Solar Results" (GSR) was addressing similar objectives in respect of quality assurance (see [7], [8]). Similar procedures and monitoring equipment were used as described in Annexes C and D. It might be necessary to update Annexes C and D at a later stage during a revision of this document when more expertise is available. As large custom built systems are by definition unique systems, only general procedures on how to check and supervise them may be given. An additional difficulty in the formulation of procedures is the fact that they have to be adapted to the dimension of the large custom built system considered, which may vary from typically 30 m² to 30 000 m² of collector area. Therefore, several possible levels of analysis are included (Annexes C and D). The objective of the two short-term system tests presented in Annex C is the characterization of system performance and/or the estimation of the ability of the system to deliver the energy claimed by the designer. In principle, two approaches for short-term system testing are referred to in this European Standard: 1) a simplified check of short-term system performance, carried out by intercomparison of the measured thermal solar system heat gain with the one predicted by simulation, using the actual weather and operating conditions as measured during the short-term test; SIST EN 12977-2:2012
EN 12977-2:2012 (E) 7 2) a short-term test for long-term system performance prediction. The performance of the most relevant components of the solar heating system is measured for a certain time period while the system is in normal operation. More detailed measurements encompass i) energy gain of collector array(s) and ii) energy balance over storage vessel(s). Inter-comparison of the observed and simulated energy quantities provides the indirect validation of collector and storage design parameters. The measured data within the collector array are also used for direct identification of the collector array parameters. As far the component parameters are verified, the long-term prediction of the system gain as well as the detection of possible sources of system malfunctioning are possible. Annex D describes a procedure for long-term monitoring as a part of the supervision of a large custom built solar heating system. The objectives of supervision may be: 3) the early recognition of possible failures of system components, in order to get the maximum benefit from the initial solar investment as well as to minimize the consumption of non-solar energy and the resulting environmental impact, 4) the measurement of system performance (solar gains or other system indicators), if requested by a contractual clause, e.g. guaranteed results. The long-term monitoring in Annex D is limited to the solar energy specific aspects, especially to the determination of the solar contribution to the total heat load. Instrumentation used in the long-term monitoring should be an integrating part of the system, a part included from the very beginning of the design process. If adequately foreseen, it may also be used for system adjustment at start time. SIST EN 12977-2:2012
EN 12977-2:2012 (E) 8 1 Scope This European Standard applies to small and large custom built solar heating systems with liquid heat transfer medium for residential buildings and similar applications, and gives test methods for verification of the requirements specified in EN 12977-1. This document also includes a method for thermal performance characterization and system performance prediction of small custom built systems by means of component testing and system simulation. Furthermore, this document contains methods for thermal performance characterization and system performance prediction of large custom built systems. This document applies to the following types of small custom built solar heating systems: systems for domestic hot water preparation only; systems for space heating only; systems for domestic hot water preparation and space heating; others (e.g. including cooling). This document applies to large custom built solar heating systems, primarily to solar preheat systems, with one or more storage vessels, heat exchangers, piping and automatic controls and with collector array(s) with forced circulation of fluid in the collector loop. This document does not apply to systems with a store medium other than water (e.g. phase- change materials), thermosiphon systems, integral collector-storage (ICS) systems. 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. EN 307, Heat exchangers — Guidelines to prepare installation, operating and maintenance instructions required to maintain the performance of each type of heat exchangers EN 806-1, Specifications for installations inside buildings conveying water for human consumption — Part 1: General EN 809, Pumps and pump units for liquids — Common safety requirements EN 1151-1, Pumps — Rotodynamic pumps — Circulation pumps having a rated power input not exceeding 200 W for heating installations and domestic hot water installations — Part 1: Non-automatic circulation pumps, requirements, testing, marking EN 1991-1-3, Eurocode 1 — Actions on structures — Part 1-3: General actions — Snow loads EN 1991-1-4, Eurocode 1: Actions on structures — Part 1-4: General actions — Wind actions SIST EN 12977-2:2012
EN 12977-2:2012 (E) 9 EN 12975-1:2006, Thermal solar systems and components — Solar collectors — Part 1: General requirements EN 12975-2:2006, Thermal solar systems and components — Solar collectors — Part 2: Test methods EN 12976-1:2006, Thermal solar systems and components — Factory made systems — Part 1: General requirements EN 12976-2:2006, Thermal solar systems and components — Factory made systems — Part 2: Test methods EN 12977-1:2012, Thermal solar systems and components — Custom built systems — Part 1: General requirements for solar water heaters and combisystems EN 12977-3:2012, Thermal solar systems and components — Custom built systems — Part 3: Performance test methods for solar water heater stores EN 12977-4:2012, Thermal solar systems and components — Custom built systems — Part 4: Performance test methods for solar combistores EN 12977-5:2012, Thermal solar systems and components — Custom built systems — Part 5: Performance test methods for control equipment EN 60335-1, Household and similar electrical appliances — Safety — Part 1: General requirements (IEC 60335-1) EN ISO 9488:1999, Solar energy — Vocabulary (ISO 9488:1999) ISO 9459-5:2007, Solar heating — Domestic water heating systems — Part 5: System performance characterization by means of whole-system tests and computer simulation ISO/TR 10217, Solar energy — Water heating systems — Guide to material selection with regard to internal corrosion 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 12975-1:2006, EN 12976-1:2006, EN 12977-1:2012, EN 12977-3:2012, EN 12977-5:2012, ISO 9459-5:2007 and EN ISO 9488:1999 apply. SIST EN 12977-2:2012
EN 12977-2:2012 (E) 10 4 Symbols and abbreviations Table 2 — Symbols, definition and unit (1 of 2) Symbol Definition Unit a1 heat loss coefficient at (ϑm – ϑa) = 0 W/(m² × K) Ac reference area of collector m² Cc effective thermal capacity of collector or collector array J/K Day day number of the year
Ds shift term for the calculation of mains water temperature at reference location
fsav fractional energy savings % fsol solar fraction % Gd diffuse solar irradiance on tilted plane W/m² Gg global solar irradiance (on horizontal plane) W/m² Gh hemispherical solar irradiance on tilted plane W/m² Hc hemispherical solar irradiation on collector plane MJ/m² Kατ incidence angle modifier
Qaux gross auxiliary energy demand of the solar heating system MJ Qaux,net net auxiliary energy demand of the solar heating system delivered by the auxiliary heater to the store or directly to the heat distribution system MJ Qconv gross energy demand of the conventional heating system MJ Qconv,net net energy demand of the conventional heating system MJ Qd heat demand MJ QL energy delivered at the outlet of the solar heating system MJ Ql store heat losses of the solar heating system MJ Ql,a store heat losses of the store heated by auxiliary energy (in case of a two-store-solar-plus-supplementary system) MJ Ql,s store heat losses of the store heated by solar energy (in case of a two-store-solar-plus-supplementary system) MJ Ql,conv store heat losses of the conventional heating system MJ Qohp heat diverted from the store as active overheating protection, if any
MJ Qpar parasitic energy (electricity) for the collector loop pump(s) and control unit MJ Qsav energy savings due to the solar heating system MJ Qsol energy delivered by the collector loop to the store MJ T* reduced temperature difference; T* = (ϑm – ϑa)/Gh m² × K/W (UA)hx heat transfer capacity rate of a heat exchanger W/K (UA)S heat loss capacity rate of the store of the solar heating system
W/K SIST EN 12977-2:2012
EN 12977-2:2012 (E) 11 Table 2 — Symbols, definition and unit (2 of 2) (UA)S,conv heat loss capacity rate of the store of the conventional heating system W/K UL overall heat loss coefficient of a collector or collector array W/(m² × K) cV& volume flow rate in collector loop l/h Vd demanded (daily) load volume l/d rcV& volume flow rate in circulation loop l/h sV& volume draw-off flow rate from storage l/h VS,conv store volume of the conventional heating system l v surrounding air speed m/s ∆ϑ average temperature difference induced by a heat exchanger K ∆ϑamplit average amplitude of seasonal mains water temperature variations on reference location K ∆η drop in system efficiency induced by a heat exchanger % ϑa collector ambient or surrounding air temperature °C ϑaverage yearly average mains water temperature
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.