BRITISH STANDARD Heating systems in buildings — Method for calculation of system energy requirements and system efficiencies Part 4-7: Space heating generation systems, biomass combustion systems ICS 91.140.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN 15316-4-7:2008 Incorporating corrigendum February 2010 BS EN 15316-4-7:2008 National foreword This British Standard is the UK implementation of EN 15316-4-7:2008 The UK participation in its preparation was entrusted to Technical Committee RHE/24, Central heating installations A list of organizations represented on this committee can be obtained on request to its secretary This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application Compliance with a British Standard cannot confer immunity from legal obligations This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2009 © BSI 2010 ISBN 978 580 70677 Amendments/corrigenda issued since publication Date Comments 31 March 2010 Correction to figures & BS EN 15316-4-7:2008 EUROPEAN STANDARD EN 15316-4-7 NORME EUROPÉENNE EUROPÄISCHE NORM November 2008 ICS 91.140.10 English Version Heating systems in buildings - Method for calculation of system energy requirements and system efficiencies - Part 4-7: Space heating generation systems, biomass combustion systems Systèmes de chauffage dans les bâtiments - Méthode de calcul des besoins énergétiques et des rendements des systèmes - Partie 4-7 : Systèmes de génération de chauffage des locaux, systèmes de combustion de la biomasse Heizungsanlagen in Gebäuden - Verfahren zur Berechnung der Energieanforderungen und Nutzungsgrade der Anlagen - Teil 4-7: Wärmeerzeugung für die Raumheizung, Biomasseverbrennungssystem This European Standard was approved by CEN on 30 September 2008 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 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 Management Centre has the same status as the official 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 STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: rue de Stassart, 36 © 2008 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members B-1050 Brussels Ref No EN 15316-4-7:2008: E BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Contents page Foreword Introduction Scope Normative references 3.1 3.2 Terms, definitions, symbols and units Terms and definitions Symbols and units 10 4.1 4.1.2 4.2 4.3 4.4 4.5 4.6 4.7 Principle of the method 11 Heat balance of the biomass combustion sub-system, including control of heat generation 11 Physical factors for biomass combustion sub-system ( biomass boiler ) taken into account 11 Calculation structure (input and output data) 12 Generation sub-system basic energy balance 13 Auxiliary energy 14 Recoverable, recovered and unrecoverable system thermal losses 14 Calculation steps 15 Using net or gross calorific values 15 Boundaries between distribution and generation sub-system 15 Biomass combustion sub-system calculation 16 Calculation method for boilers with automatic stocking 16 7.1 7.2 7.2.1 7.2.2 7.2.3 7.2.4 7.2.5 7.3 7.3.1 7.3.2 7.3.3 7.3.4 7.3.5 7.3.6 7.3.7 7.3.8 7.4 7.4.1 7.4.2 7.4.3 7.4.4 7.4.5 7.4.6 7.4.7 Calculation method for boilers with stocking by hand 16 Available methodologies 16 Operation periods 16 General 16 Heating up operation cycle 17 Boiler heating operation cycle 17 Cooling down operation cycle 17 Boiler non operation cycle 18 Case specific boiler efficiency method 18 Principle of the method 18 Input data to the method 19 Load of the boiler 20 Biomass boiler thermal losses 21 Total auxiliary energy 23 Recoverable generation system thermal losses 24 Fuel input 25 Operating temperature of the biomass boiler 25 Boiler cycling method 26 Principle of the method 26 Input data for the calculation method 28 Load factor 29 Specific thermal losses 29 Total thermal losses 33 Auxiliary energy 33 Recoverable system thermal losses 34 4.1.1 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) 7.4.8 Calculation procedure for a modulating biomass boiler (fan assisted) 34 Annex A (informative) Additional formulas and default values for parametering the case specific boiler efficiency method 35 A.1 Information on the method 35 A.1.1 Basic assumptions and intended use 35 A.1.2 Known approximations 35 A.2 Boiler efficiencies and stand-by heat losses 35 A.2.1 Default values for boiler efficiency at full load and intermediate load as a function of the boiler power output 35 A.2.2 Stand-by heat losses 36 A.2.3 Correction factor taking into account variation of efficiency depending on boiler average water temperature 37 A.3 Auxiliary energy 38 A.4 Recoverable boiler thermal losses 38 A.4.1 Auxiliary energy 38 A.4.2 Thermal losses (boiler envelope) 39 A.4.3 Default data according to boiler location 39 Annex B (informative) Additional formulas and default values for parametering the boiler cycling method 40 B.1 Information on the method 40 B.1.1 Basis assumptions and intended use 40 B.1.2 Known approximations 40 B.2 Default specific losses 40 B.2.1 Default data for calculation of thermal losses through the chimney with boiler on 40 B.2.2 Default values for calculation of thermal losses through the boiler envelope 41 B.2.3 Default values for calculation of thermal losses through the chimney with the boiler off 42 B.3 Default values for calculation of auxiliary energy 43 B.4 Additional default data for modulating burners 43 Annex C (informative) Storage systems for biomass combustion systems 45 C.1 General 45 C.1.1 Accumulator storage system 45 C.1.2 Load balancing storage system 45 C.2 Sizing of storage systems for biomass combustion systems 45 C.2.1 Sizing of the volume of the accumulator storage tank 45 C.2.2 Sizing of the volume of the load balancing tank 46 C.3 System thermal losses of storage systems 46 C.3.1 Thermal losses 46 C.3.2 Auxiliary energy of the circulation pump 47 Annex D (informative) Calculation procedure with an example for biomass boiler with stocking by hand - Case specific boiler efficiency method 48 Annex E (informative) Calculation procedure with an example for biomass boiler with stocking by hand (Cycling method) 50 Bibliography 53 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Foreword This document (EN 15316-4-7:2008) has been prepared by Technical Committee CEN/TC 228 “Heating systems in buildings”, the secretariat of which is held by DS 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 May 2009, and conflicting national standards shall be withdrawn at the latest by May 2009 This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association (Mandate M/343), and supports essential requirements of EU Directive 2002/91/EC on the energy performance of buildings (EPBD) It forms part of a series of standards aimed at European harmonisation of the methodology for calculation of the energy performance of buildings An overview of the whole set of standards is given in CEN/TR 15615 The subjects covered by CEN/TC 228 are the following: design of heating systems (water based, electrical etc.); installation of heating systems; commissioning of heating systems; instructions for operation, maintenance and use of heating systems; methods for calculation of the design heat loss and heat loads; methods for calculation of the energy performance of heating systems Heating systems also include the effect of attached systems such as hot water production systems All these standards are systems standards, i.e they are based on requirements addressed to the system as a whole and not dealing with requirements to the products within the system Where possible, reference is made to other European or International Standards, a.o product standards However, use of products complying with relevant product standards is no guarantee of compliance with the system requirements The requirements are mainly expressed as functional requirements, i.e requirements dealing with the function of the system and not specifying shape, material, dimensions or the like The guidelines describe ways to meet the requirements, but other ways to fulfil the functional requirements might be used if fulfilment can be proved Heating systems differ among the member countries due to climate, traditions and national regulations In some cases requirements are given as classes so national or individual needs may be accommodated In cases where the standards contradict with national regulations, the latter should be followed EN 15316 Heating systems in buildings — Method for calculation of system energy requirements and system efficiencies consists of the following parts: Part 1: General BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Part 2-1: Space heating emission systems Part 2-3: Space heating distribution systems Part 3-1: Domestic hot water systems, characterisation of needs (tapping requirements) Part 3-2: Domestic hot water systems, distribution Part 3-3: Domestic hot water systems, generation Part 4-1: Space heating generation systems, combustion systems (boilers) Part 4-2: Space heating generation systems, heat pump systems Part 4-3: Heat generation systems, thermal solar systems Part 4-4: Heat generation systems, building-integrated cogeneration systems Part 4-5: Space heating generation systems, the performance and quality of district heating and large volume systems Part 4-6: Heat generation systems, photovoltaic systems Part 4-7: Space heating generation systems, biomass combustion systems 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 United Kingdom BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Introduction This European Standard presents methods for calculation of the additional energy requirements of a heat generation system by biomass combustion in order to meet the distribution and/or storage sub-system demand The calculation is based on the performance characteristics of the products given in product standards and on other characteristics required to evaluate the performance of the products as included in the system This method can be used for the following applications: judging compliance with regulations expressed in terms of energy targets; optimisation of the energy performance of a planned heat generation system, by applying the method to several possible options; assessing the effect of possible energy conservation measures on an existing heat generation system, by calculating the energy use with and without the energy conservation measures The user needs to refer to other European Standards or to national documents for input data and detailed calculation procedures not provided by this European Standard Scope This European Standard is part of a series of standards on the method for calculation of system energy requirements and system efficiencies of space heating systems and domestic hot water systems The scope of this specific part is to standardise the: required inputs; calculation method; resulting outputs, for space heating generation by biomass combustion sub-systems (boilers) with stocking by hand, including control This European Standard is also intended for the case of generation for both domestic hot water production and space heating The case of generation only for domestic hot water production is treated in EN 15316-3-3 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 303-5, Heating boilers — Part 5: Heating boilers for solid fuels, hand and automatically stocked, nominal heat output of up to 300 kW — Terminology, requirements, testing and marking EN ISO 7345:1995, Thermal insulation — Physical quantities and definitions (ISO 7345:1987) BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) EN 15316-2-3, Heating systems in building — Method for calculation of system energy requirements and system efficiencies — Part 2-3: Space heating distribution systems EN 15316-3-2, Heating systems in building — Method for calculation of system energy requirements and system efficiencies — Part 3-2: Domestic hot water systems, distribution EN 15316-3-3, Heating systems in building — Method for calculation of system energy requirements and system efficiencies — Part 3-3: Domestic hot water systems, generation EN 15316-4-1:2005, Heating systems in building — Method for calculation of system energy requirements and system efficiencies — Part 4-1: Space heating generation systems, combustion systems (boilers) 3.1 Terms, definitions, symbols and units Terms and definitions For the purposes of this document, the terms and definitions given in EN ISO 7345:1995 and the following apply 3.1.1 space heating process of heat supply for thermal comfort 3.1.2 domestic hot water heating process of heat supply to raise the temperature of the cold water to the intended delivery temperature 3.1.3 heated space room or enclosure which for the purposes of the calculation is assumed to be heated to a given set-point temperature or set-point temperatures 3.1.4 system thermal loss thermal loss from a technical building system for heating, cooling, domestic hot water, humidification, dehumidification, ventilation or lighting that does not contribute to the useful output of the system NOTE Thermal energy recovered directly in the subsystem is not considered as a system thermal loss but as heat recovery and is directly treated in the related system standard 3.1.5 auxiliary energy electrical energy used by technical building systems for heating, cooling, ventilation and/or domestic hot water to support energy transformation to satisfy energy needs NOTE This includes energy for fans, pumps, electronics etc Electrical energy input to the a ventilation system for air transport and heat recovery is not considered as auxiliary energy, but as energy use for ventilation 3.1.6 heat recovery heat generated by a technical building system or linked to a building use (e.g domestic hot water) which is utilised directly in the related system to lower the heat input and which would otherwise be wasted (e.g preheating of the combustion air by flue gas heat exchanger) 3.1.7 total system thermal loss total of the technical system thermal loss, including recoverable system thermal losses BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) 3.1.8 recoverable system thermal loss part of the system thermal loss which can be recovered to lower either the energy need for heating or cooling or the energy use of the heating or cooling system 3.1.9 recovered system thermal loss part of the recoverable system thermal loss which has been recovered to lower either the energy need for heating or cooling or the energy use of the heating or cooling system 3.1.10 gross calorific value quantity of heat released by a unit quantity of fuel, when it is burned completely with oxygen at a constant pressure equal to 101 320 Pa, and when the products of combustion are returned to ambient temperature NOTE This quantity includes the latent heat of condensation of any water vapour contained in the fuel and of the water vapour formed by the combustion of any hydrogen contained in the fuel NOTE According to ISO 13602-2, the gross calorific value is preferred to the net calorific value NOTE The net calorific value does not take into account the latent heat of condensation 3.1.11 net calorific value gross calorific value minus latent heat of condensation of the water vapour in the products of combustion at ambient temperature 3.1.12 calculation step discrete time interval for the calculation of the energy needs and uses for heating, cooling, humidification and dehumidification NOTE Typical discrete time intervals are one hour, one day, one month or one heating and/or cooling season, operating modes, and bins 3.1.13 calculation period period of time over which the calculation is performed NOTE The calculation period can be divided into a number of calculation steps 3.1.14 external temperature temperature of external air NOTE For transmission heat transfer calculations, the radiant temperature of the external environment is supposed equal to the external air temperature; long-wave transmission to the sky is calculated separately NOTE The measurement of external air temperature is defined in EN ISO 15927-1 3.1.15 boiler gas, liquid or solid fuelled appliance designed to provide hot water for space heating It may (but need not) be designed to provide domestic hot water heating as well 3.1.16 combustion power product of the fuel flow rate and the net calorific power of the fuel BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Annex B (informative) Additional formulas and default values for parametering the boiler cycling method B.1 Information on the method B.1.1 Basis assumptions and intended use This method is intended for use with existing boilers, where data are declared according to relevant standards This methodology is based on a physical analysis of losses (indirect method) and takes into account two operating conditions: boiler in operation; boiler in non operation ( off or fire bed ) This methodology is suitable for modulating boilers in operation or in non operation All data given in this annex are based on net calorific values Hi If losses have to be calculated according to gross calorific value Hs, this has to be done in accordance with the procedure given in 4.6 B.1.2 Known approximations Losses through the chimney with boiler in non operation are not easily measured However, this loss factor has a reduced impact for new boilers with air intake closure at stand-by B.2 Default specific losses B.2.1 Default data for calculation of thermal losses through the chimney with boiler on Table B.1 — Default value of θgnr,w,m,test, P’ch,on and fcorr θgnr,w,m,test P’ch,on θi,brm,test fcorr °C % °C %/°C Atmospheric biomass boiler 70 14 20 0,045 Fan assisted biomass boiler 70 12 20 0,045 Description 40 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Table B.2 — Default value of exponent n Description Biomass standard boiler Heavy mass boiler cmass n kg/kW - to 0,1 >2 0,15 NOTE cmass in kg/kW is the ratio between the mass of the heat exchange surface between flue gas and water and nominal combustion power of the boiler B.2.2 Default values for calculation of thermal losses through the boiler envelope The default losses through the boiler envelope P'gnr,env are given by: Φ P' gnr ,env = c1 − c2 ⋅ log cmb 000 (B.1) where c1, c2 parameters given in Table B.3; Φcmb boiler nominal combustion power in W Table B.3 — Default value of parameters c1 and c2 c1 c2 % % Well insulated, high efficiency new boiler 1,72 0,44 Well insulated and maintained 3,45 0,88 Old boiler with average insulation 6,90 1,76 Old boiler, poor insulation 8,36 2,20 No insulation 10,35 2,64 Boiler insulation type Table B.4 — Default value of reduction factor kgnr,env, test room temperature θi,brm,test and installation room temperature θi,brm Boiler type and location kgnr,env θi,brm,test θi,brm - °C °C Boiler installed within the heated space 0,1 20 Atmospheric boiler installed within the heated space 0,2 20 Boiler installed within a boiler room 0,7 Boiler installed under roof 0,8 Boiler installed outdoors 1,0 External temperature 20 13 41 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Table B.5 — Default value of exponent m Description cgnr m kg/kW - The primary pump is always running The primary pump stops after the boiler turns to non operation 0,0 to 0,10 NOTE cgnr in kg/kW is the ratio between the total weight of the boiler (metal + refractory materials + insulating materials) and the nominal combustion power of the boiler B.2.3 Default values for calculation of thermal losses through the chimney with the boiler off Table B.6 — Default value of P'ch,off P’ch,off Description % Biomass fired boiler with the fan before the combustion chamber and automatic closure of air intake with burner off 0,2 Biomass fired boiler with the fan before the combustion chamber and no closure of air intake with burner off: Chimney height ≤ 10 m 1,0 Chimney height > 10 m 1,2 Atmospheric biomass boiler: Chimney height ≤ 10 m 1,2 Chimney height > 10 m 1,6 Table B.7 — Default value of exponent p Description cgnr p kg/kW - The primary pump is always running 0,0 The primary pump stops after the boiler turns to non operation Steel boiler Heavy mass boiler to 0,10 >3 0,05 NOTE cgnr in kg/kW is the ratio between the total weight of the boiler (metal + refractory materials + insulating materials) and the nominal combustion power of the boiler 42 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) B.3 Default values for calculation of auxiliary energy The default auxiliary power consumption Pbr and Ppmp are given by Px = c3 + c ⋅ Φ cmb /1 000 (B.2) where Φcmb is the boiler nominal combustion power in W Table B.8 — Default value of c3 and c4 for the calculation of electrical power consumption of auxiliary devices c3 c4 W W Biomass standard boiler 10 Fan assisted boiler 15 2,0 Description NOTE If there is no primary pump, then Ppmp = The part of the auxiliary energy which is recoverable for space heating frbl,aux is given by: f rbl , aux = − f rvd , aux (B.3) where frvd,aux is the recovered part of the auxiliary energy, which is transmitted to the distribution sub-system Default value of frvd,aux is given in Table B.9 along with default values of temperature reduction factor according to boiler location Table B.9 — Default value of temperature reduction factor bbrm and auxiliary energy recovery factor frvd,aux Boiler location Temperature reduction factor Auxiliary energy recovery factor bbrm - frvd,aux - Outdoors B.4 In the boiler room 0,3 Under roof 0,2 Inside heated space 0,0 0,8 Additional default data for modulating burners The default minimum combustion power of the boiler is given by: Φcmb,min = Φcmb · fmin (B.4) where 43 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) fmin parameter given in Table B.10; Φcmb boiler nominal (maximum) combustion power Table B.10 — Parameter fmin for modulating burners fmin Description - Fan assisted biomass boiler 0,5 Table B.11 — Default value of θgnr,w,m,test,min and P’ch,on,min θgnr,w,m,test,min P’ch,on,min °C % Atmospheric boiler 70 11 Force draught gas boiler 70 Description The default auxiliary power consumption Pbr,min is calculated with Equation (B.2) using: Φcmb,min instead of Φcmb; c3 and c4 given in Table B.12 Table B.12 — Default value of c3 and c4 for the calculation of electrical power consumption of auxiliary devices at minimum combustion power c3 c4 W W Biomass standard boiler 10 Fan assisted boiler 15 2,0 Description 44 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Annex C (informative) Storage systems for biomass combustion systems C.1 General C.1.1 Accumulator storage system According to EN 303-5, it is recommended to extend the boiler system with stocking by hand by an accumulator storage system, if the relation between the nominal heat output of the boiler Фgnr,nom and the design heat load Pbg,nom is greater than 1,5 The main objective of an accumulator storage system for the boiler is to: store the heat between the operation cycles; improve the heating comfort for the user A further objective is, as with a load balancing storage system, to improve the operation conditions regarding thermal efficiency and environmental impact as well An accumulator storage system comprises the following components: accumulator storage tank; distribution piping between the boiler and the accumulator storage tank, including circulation pump; control device C.1.2 Load balancing storage system The object of a load balancing storage system for boilers is to improve the operation conditions regarding thermal efficiency and environmental pollution by: reduction of the start and stop cycles during the operation of the automatic fired boilers; extension of the minimum running time between the start operation and stop operation Load balancing storage systems are used for boilers with automatic stocking The load balancing storage system comprises similar components as for an accumulator storage system, but the sizing of the storage tank is quite different C.2 C.2.1 Sizing of storage systems for biomass combustion systems Sizing of the volume of the accumulator storage tank The volume of the accumulator storage tank Vacc,ta is determined by: Vacc, ta = 15 × t gnr , on × Φ gnr , nom × (1 − 0,3 × Φ gnr , nom ) Pbg , nom (C.1) 45 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) where tgnr,on operation time of the boiler (h); Φgnr,nom nominal heat output of the boiler(s) (kW); Pbg,nom (design) heat load of the building (kW) Default value for the volume of the accumulator storage tank C.2.2 Vacc ,ta = 50 × Pbg ,nom (litres) (C.2) Sizing of the volume of the load balancing tank The volume of the load balancing storage tank Vlob,ta is calculated by: Vlob,ta = ( Qgnr,100 × tgnr,op,min × 14,33 ) / ∆θgnr,op,stst - Vgnr,he,med - Vpip,dis,he,med (C.3) where Qgnr,100 nominal heat output of the boiler(s) kW; tgnr,op,min minimum time between the start and stop of the operation cycle min; ∆θgnr,op,stst temperature difference between start operation and stop operation of the boiler K; Vgnr,he,med volume of the heating medium of the boiler litres; Vpip,dis,he,med volume of the heating medium of the distribution piping before control devices litres Default value for the volume of the load balancing storage tank C.3 Vlob ,ta = 25 × Pbg ,nom (litres) (C.4) System thermal losses of storage systems C.3.1 Thermal losses C.3.1.1 Thermal losses of the storage tank Calculation of the thermal losses of the accumulator or load balancing storage tank Qsto,ls,ta is similar to the calculation for storage tanks for domestic hot water Relevant values are given by: information by the manufacturer (standby value); calculation procedure according to the specification for storage tanks (see EN ISO 12241) C.3.1.2 Thermal losses of the storage piping Calculation of the thermal losses of the accumulator or load balancing storage piping Qsto,ls,pip is similar to the calculation for storage tanks for domestic hot water Relevant values are given by: information by the manufacturer (standby value); calculation procedure according to the specification for the domestic hot water storage piping 46 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) C.3.1.3 Total thermal losses The total thermal losses of the accumulator or load balancing storage system Qsto,ls are calculated by: Qsto,ls = Qsto,ls,ta + Qsto,ls,pip C.3.2 (C.5) Auxiliary energy of the circulation pump The auxiliary energy of the circulation pump Wsto,aux,pu is calculated by: Wsto,aux,pu = fcorr,ci × Φel,pu × tci (C.6) where fcorr,ci correction factor running time Default value fcorr,ci = 0,12 (-); Φel,pu nominal output of the circulation pump (kW); tci running time of the circulation pump (h) The recoverable auxiliary energy of the circulation pump Qsto,aux,pu,rbl is calculated by: where fsto,sys Qsto,aux,pu,rbl = Wsto,aux,pu × fsto,sys (C.7) factor considering the operation conditions of the storage system Default value for fsto,sys = 0,75 47 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Annex D (informative) Calculation procedure with an example for biomass boiler with stocking by hand - Case specific boiler efficiency method Description Advise Calculation Specific boiler data Type of biomass combustion system Standard boiler, constant boiler running temperature, no accumulating storage tank Type of control Modulating, fan assisted Nominal power ( 100 % load ) ФPn = 36,0 kW Full load efficiency based on test results Test value ηgnr,Pn = 88 % Intermediate part load Test value ФPint = 18,0 kW Intermediate part load efficiency Test value ηgnr,Pint = 90 % Θgnr,w,min = 60 °C Minimum boiler temperature Other input data: Energy supplied to the distribution system EN 15361-3-2 Qgnr,out = 000 kWh/ month Calculation period month, tgnr,tot = tci = 30 × 24 = 720 h Boiler location Inside boiler room Boiler room temperature Table A.8 Θi,brm = 13 °C Calculation procedure Θgnr,w,m = 65 °C Average water temperature in the boiler Correction factor for 100% load Table A.4 fcorr,Pn = 0,04 % / °C Boiler average water temperature at test conditiones Table A.4 Θgnr,w,test,Pn = 70 °C Corrected boiler efficiency at 100% load Equation (12) ηgnr,Pn,corr = 88,0 + 0,04 × ( 70 - 65 ) = 88,2 % Corrected boiler thermal loss at 100% load Equation (13) Фgnr,ls,Pn,corr = ((100 – 88,2 ) / 88,2)) × 36 = 4,82 kW Correction factor for intermediate load Table A.5 fcorr,Pint = 0,05 % / °C Boiler average water temperature at test conditiones Table A.5 Θgnr,w,test,Pint = 70 °C Corrected boiler efficiency at intermediate load Equation (14) ηgnr,Pint,cor = 90,0 + 0,05 × ( 70 - 65 ) = 90,25 % Corrected boiler thermal loss at intermediate load Equation 15 Фgnr,ls,Pint,corr = ((100 – 90,25) / 90,25)) × 18 = 1,94 kW 48 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Thermal losses Parameters for fire bed (standby) operation Table A.3 c5 = 8,5 c6 = - 0,4 Thermal loss at 0% load (fire bed operation ) Equation A.3 Фgnr,ls,P0 = 36 × (8,5/100) × (36 000/1 000) Corrected boiler thermal loss at 0% load Equation (16), Boiler average power Equation (9) Фgnr,out = 000 / 720 = 8,33 kW Specific load ratio Equation (10) βgnr = 8,33 / 36 = 0,23 Power output at specific load ratio Equation (17) ФPx = 36,0 × 0,23 = 8,33 kW Boiler thermal loss at specific heat load Equation (18) Фgnr,ls,Px, = (8,33/18) × (1,94 – 0,77) + 0,77 Total boiler thermal loss Equation (20) Qgnr,ls = 1,31 × 24 × 30 = 943,2 kWh/month Recoverable boiler thermal losses Equation (28), A.4.2, A.4.3 Qgnr,ls,env,rbl = 0,77 × (1 - 0,3) 0,75 × 720 Parameters, power consumption of auxiliaries at intermediate load Table A.6 c7 = 0, c8 = 15, n = 0,48 Power consumption of auxiliary equipment at intermediate load Equation (A.6) Paux,Pint = + 15 x 18 Parameters, power consumption of auxiliaries at fire bed operation Table A.6 c7 = 15, c8 = 0, n = Power consumption of auxiliary equipment at fire bed operation Equation (A.6) Paux,P0 = 15 + = 15 W Power consumption of auxiliary equipment at specific heat load Equation (23) Paux,Px = 15 + ( 0,23 / (18,0 / 36,0)) × (60 – 15) Auxiliary energy Equation (22) Wgnr,aux = 35,7 × 720 + = 25,7 kWh/month Recovered auxiliary energy to the heating medium Equation 26, A.4.1 Qgnr,aux,rvd = 25,7 × 0,75 = 19,3 kWh/month Recoverable auxiliary energy to the heated space Equation (27), A.4.1, A.4.3 Qgnr,aux,rbl = 25,7 × (1 – 0,3) × 0,25 = 4,5 kWh/month Equation (1) Egnr,in = 000 - 19,3 + 943,2 = 923,9 kWh/month -0,4 = 36 × 0,085 × 0,238 = 36 × 0,002 = 0,73 kW Table A.3 Фgnr,ls,P0,corr = 0,73 × ((65 – 13)/(50)) 1,25 = = 0,73 × 1,05 = 0,77 kW = 1,31 kW = 291,1 kWh/month Auxiliary energy 0,48 = 60 W = 35,7 W Output data Fuel heat requirement Total system thermal losses Qgnr,ls,tot = Qgnr,ls + (Wgnr,aux - Qgnr,aux,rvd) = 943,2 + ( 25,7 – 19,3 ) = 949,6 kWh/month Total recoverable system thermal losses Monthly efficiency of the biomass boiler Equation (30) Qgnr,ls,rbl = 291,1 + 4,5 = 295,6 kWh/month ηgnr,m = - Qgnr,ls / (Qgnr,out + Qgnr,ls ) = – 943,2 / (6 000 + 943,2) = = - 0,136 = 86,4 % 49 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Annex E (informative) Calculation procedure with an example for biomass boiler with stocking by hand (Cycling method) Description Advise Calculation Specific boiler data Type of biomass combustion system Standard boiler, constant boiler running temperature, no accumulating storage tank Type of control Modulating, fan assisted Nominal power ( 100 % load ) Фcmb = Фref = 36,0 kW Minimum combustion power Test value Фcmb,min = 18,0 kW Volume burning chamber Test value Vcham = 146 litres = 0,146 m Specific heat loss through the chimney with boiler ON ( Flue gas loss ) at test conditions Table B.1 P’ch,on = 12,0 % Specific heat loss through the chimney with boiler OFF (flue gas loss) at test conditions Table B.6 P’ch,off = 1,2 % Average water temperature in the boiler at test conditions Table B.1 Θgnr,w,m,test = 70 °C Room temperature at test conditions Table B.1 Θi,brm,test = 20 °C Parameters for default heat losses through boiler envelope (well insulated and maintained) Table B.3 c1 = 3,45, c2 = 0,88 Specific heat loss through the boiler envelope Equation (B.1) P'gnr,env = c1 – c2 × ( log ФPn /1 000 ) = 3,45 – 0,88 × log36 = 3,45 – 0,88 ×1,556 = 2,1 % Other input data: Energy supplied to the distribution system EN 15316-3-2 Qgnr,out = 000 kWh/month Caloric net value ( log wood ) Hi,fuel = 850 kWh/rm Heat output each filling Фcham = Vcham × Hi,fue × (100 – P’ch,on – P’gnr,env) / 100 = 0,146 × 850 × ( – 0,12 – 0,021 ) = 232,0 kWh Interval of chamber filling tgnr,fill = 24 h Operation period ON (min load) tgnr,on = Фcham / Фcmb,min = 232,0 / 18 = 12,9 h Operation period OFF (fire bed) tgnr,off = tgnr,fill - tgnr,on = 24,0 – 12,9 = 11,1 h 50 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Calculation period month, tci = 30 × 24 = 720 h Chimney height 11,0 m Boiler location Inside boiler room Boiler room temperature Table B.4 Θi,brm = 13 °C Θgnr,w,m = 65 °C Running temperature of the boiler Calculation procedure Load factor during boiler ON (min load) Equation (33) FCgnr,on = 18,0 / 36,0 = 0,5 Load factor during boiler fire bed operation Equation (33) FCgnr,off = / 36,0 = Correction factor for P’ch,on Table B.1 fcorr = 0,045 % / °C Exponent for load factor Table B.2 n = 0,1 Specific thermal loss through the chimney with the boiler ON Equation (34) Pch,on = (12 + ( 65 – 70 ) × 0,045) × 0,50,1 Thermal loss through the chimney with boiler ON (reference load) Equation (39) Exponent for load factor Table B.5 m = 0,1 Reduction factor Table B.4 kgnr,env = 0,7 Specific thermal loss through the envelope at minimum load Equation (35) Pgnr,env = 2,1 × 0,7 × (65 – 13)/(70 – 20) × 0,5 Thermal loss through the boiler envelope at minimum load and fire bed operation Equation (41) Qgnr,env = ( 1,4 / 100 ) × 18 × 24 = 6,0 kWh/day Exponent for load factor Table B.7 p = 0,1 Specific thermal loss through the chimney with the boiler OFF Equation (38) Pch,off = 1,2 × ( 65 - 13 ) / ( 70 - 20 ) × 0,50,1 Thermal loss through the chimney with boiler OFF Equation (40) Qch,off = ( 1,2 / 100 ) × 18,0 × 11,1 = 2,4 kWh/day Total boiler thermal loss Equation (42) Qgnr,ls = ( Qch,on + Qch,off + Qgnr,ge ) × 30 Thermal losses = 11,0 % Qch,on = (11,0 / 100) × 18 × 12,9 = 25,5 kWh/day 0,1 = 1,4 % = 1,2 % = (25,5 + 6,0 + 2,4) × 30 = 017,0 kWh/month 7.4.6.2 Qgnr,ls,env,rbl = kWh/month Default values for the electric power consumption of auxiliary devices Table B.8 For tON c3 = 15 W c4 = 2,0 % For tOFF c3 = 15 W c4 = Specific electric power of the auxiliary equipment for tON Equation (B.2) Px,0N = 15 + 2,0 × ( 36 000 /1 000) = 87 W Specific electric power of the auxiliary equipment for tOFF Equation (B.2) Px,0FF = 15 + = 15 W Recoverable boiler thermal losses Auxiliary energy 51 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Total auxiliary energy Equation (43) Wgnr,aux = ( 87 × 12,9 + 15 × 11,1 ) × 30 = 38,6 kWh/month Recovered auxiliary energy Table B.9 Qgnr,aux,rvd = 38,6 × 0,8 = 30,9 kWh/month Recoverable auxiliary energy to the heated space Equation (44), B.3 Qgnr,aux,rbl = 38,6 × ( – 0,3 ) × ( - 0,8 ) Equation (1) Egnr,in = 000 – 30,9 + 017,0 = 5,4 kWh/month Output data Fuel heat requirement = 986,1 kWh/month Total system thermal losses Qgnr,ls,tot = Qgnr,ls + ( Wgnr,aux - Qgnr,aux,rvd ) = 017,0 + (38,6 – 30,9) = 024,7 kWh/month Total recoverable system thermal losses Monthly efficiency of the biomass boiler Equation (45) Qgnr,ls,rbl = + 5,4 = 5,4 kWh/month ηgnr,m = - Qgnr,ls / (Qgnr,out + Qgnr,ls ) = (1 – 017,0 / (6 000 + 017,0) = – 0,145 = 85,6 % 52 BS EN 15316-4-7:2008 EN 15316-4-7:2008 (E) Bibliography [1] Council Directive 92/42/EEC of 21 May 1992 about the efficiency requirements of the new gas or oil boilers [2] EN ISO 15927-1, Hygrothermal performance of buildings — Calculation and presentation of climatic data — Part 1: Monthly means of single meteorological elements (ISO 15927-1:2003) [3] ISO 13602-2, Technical energy systems — Methods for analysis — Part 2: Weighting and aggregation of energywares [4] EN ISO 13790, Thermal performance of buildings — Calculation of energy use for space heating and cooling (ISO 13790:2004) [5] CEN/TS 14588:2003, Solid biofuels — Terminology, definitions and descriptions [6] CEN/TS 14961, Solid fuels — Fuel specification and classes [7] EN 15603, Energy performance of buildings — Overall energy use and definition of energy ratings 53 BS EN 15316-4-7:2008 BSI - British Standards Institution BSI is the independent national body responsible for preparing British Standards It presents the UK view on standards in Europe and at the international level It is incorporated by Royal Charter Revisions British Standards are updated by amendment or revision Users of British Standards should make sure that they possess the latest amendments or editions It is the constant aim of BSI to improve the quality of our products and services We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover Tel: +44 (0)20 8996 9000 Fax: +44 (0)20 8996 7400 BSI offers members an individual updating service called PLUS which ensures 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