Heating systems in buildings - Energy performance of buildings - Overall energy use, primary energy and CO2 emissions

The purpose of this standard is to:
   collate results from other standards that specify calculation of energy consumption within a building;
   account for energy generated in the building, some of which may be exported for use elsewhere;
   present a summary on tabular form of the overall energy use of the building;
   specify calculation of primary energy consumption and carbon dioxide emission for the building as a whole;
   establish general principles for the calculation of primary energy factors and carbon dioxide emission factors.
This standard will provide:
a definition of system boundaries (e.g. building, installations, energy supply) and calculation periods;
general definition of the overall energy use (i.e. determine which services are taken into account within the system boundaries);
definition of energy terms (energy use, primary energy, etc.);
definition of the data interfaces with other standards in order to report the overall energy use of buildings;
general procedures for taking into consideration decentralised energy production based on renewable energy and CHP (combined heat and power production), e.g. to show how on-site energy generation offsets energy demand;
identification of the energy streams across system boundaries;
principles for assessing primary energy consumption and CO2 emission of buildings (i.e. principles for determining primary energy factors and carbon dioxide emission factors);
general principles for taking into account the interactions between the different energy uses (e.g. calculation of recovered losses and gains).
The objective of specifying the details of the energy performance calculation for a building is to:
- underline the particularity of a project (e.g. efforts made on bioclimatic design);
- show the strong and the weak points in the overall energy performance of the building and to highlight potential gains:
- distinguish between thermal uses and specific electrical uses;
- indicate the outputs required f

Heizsysteme in Gebäuden - Energieeffizienz von Gebäuden - Gesamtenergieverbrauch, Primärenergie und CO2-Emissionen

Der Zweck dieser Norm besteht in Folgendem:
Zusammenstellen und Ordnen der Ergebnisse weiterer Normen, in denen die Berechnung des Energieverbrauchs in einem Gebäude festgelegt wird;
Bestimmung der in einem Gebäude erzeugten Energie, die teilweise für den Verbrauch an anderer Stelle nach außen abgegeben werden kann;
Liefern einer tabellarischen Zusammenfassung des Gesamtenergieverbrauchs des Gebäudes;
Festlegung der Berechnung des Primärenergieverbrauchs und der Kohlendioxid Emissionen für das gesamte Gebäude;
Festlegung allgemeiner Grundsätze für die Berechnung der Primärenergiefaktoren und der Faktoren für die Kohlendioxid Emission;
Die vorliegende Norm bietet Folgendes:
-   eine Definition der Anlagengrenzen (z. B. Gebäude, Installationen, Energieversorgung) und der Berechnungszeiträume;
-   eine allgemeine Definition des Gesamtenergieverbrauchs (d. h. die Bestimmung der Leistungen, die innerhalb der Anlagengrenzen berücksichtigt werden);
-   eine Definition der energiebezogenen Begriffe (Energieverbrauch, Primärenergie usw.);
-   eine Definition der Datenschnittstellen mit weiteren Normen, um Angaben zum Gesamtenergieverbrauch von Gebäuden machen zu können;
-   allgemeine Verfahren zur Berücksichtigung einer auf erneuerbaren Energien und KWK (Kraft Wärme Kopplung) beruhenden dezentralen Energieerzeugung, z. B. um darzustellen, wie die Energieerzeugung vor Ort den Energiebedarf verändert;
-   Identifizierung von über die Anlagengrenzen hinaus verlaufenden Energieströmen;
-   Grundsätze für die Bewertung des Primärenergieverbrauchs und der CO2 Emissionen von Gebäuden, (d. h. Grundsätze für die Bestimmung von Primärenergiefaktoren und Faktoren für die Kohlendioxid Emissionen);
-   allgemeine Grundsätze für die Berücksichtigung der Wechselwirkungen zwischen den verschiedenen Energieverwendungszwecken (z. B. Berechnung der rückgewonnenen Verluste und Gewinne).

Systèmes de chauffage dans les bâtiments - Performance énergétique des bâtiments - Energie globale, énergie primaire et émissions de CO2

Ogrevalni sistemi v stavbah - Energijske lastnosti stavb - Splošna raba energije. osnovna energija in emisije CO2

General Information

Status
Not Published
Current Stage
4060 - Closure of enquiry - Enquiry
Due Date
28-Dec-2005
Completion Date
28-Dec-2005

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oSIST prEN 15315:2005SLOVENSKIseptember 2005

PREDSTANDARDHeating systems in buildings - Energy performance of buildings - Overall energy use, primary energy and CO2 emissions©

Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljenoReferenčna številkaoSIST prEN 15315:2005(en)ICS91.140.10

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMDRAFTprEN 15315July 2005ICSEnglish versionHeating systems in buildings - Energy performance of buildings -Overall energy use, primary energy and CO2 emissionsThis draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 228.If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations whichstipulate the conditions for giving this European Standard the status of a national standard without any alteration.This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other languagemade by translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the samestatus as the official versions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice andshall not be referred to as a European Standard.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36

B-1050 Brussels© 2005 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. prEN 15315:2005: E

prEN 15315:2005 (E) 2 Contents Page Foreword..............................................................................................................................................................3 Introduction.........................................................................................................................................................4 1 Scope......................................................................................................................................................5 2 Normative references............................................................................................................................6 3 Definitions and symbols.......................................................................................................................7 4 Principle of the method.......................................................................................................................10 5 Calculation of the primary energy and CO2 emissions....................................................................18 Annex A (informative)

Primary energy factors and CO2 emission factors................................................23 Annex B (informative)

Overview of the different parameters influencing the integrated energy performance of buildings....................................................................................................................24

prEN 15315:2005 (E) 3 Foreword This document (prEN 15315:2005) has been prepared by Technical Committee CEN/TC 228 “Heating systems in buildings”, the secretariat of which is held by DS. This document is currently submitted to the CEN Enquiry. 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.

prEN 15315:2005 (E) 4 Introduction This standard specifies a general framework for the assessment of overall energy use of a building and calculation of overall energy performance in terms of primary energy and CO2 emissions. Separate standards specify calculation of the energy consumption of services within a building (i.e. heating, cooling, ventilation, domestic hot water, lighting). In the present standard, these energy consumptions are considered for calcula-tion of the overall energy use. Allowance is made for energy that may be generated within, or on the surface of, the building, and which is used to offset fuel and power drawn from other sources. Electrical energy generated in excess of the instantaneous demand is considered, provided it is exported to the public supply for use elsewhere. A comprehensive approach is needed for appropriate evaluation of all options to improve the energy performance of buildings. The assessment is not limited to the building alone, but takes into account the wider environmental impact of the energy supply chain. From an assessment of overall energy use, building owners and policy-makers can gain an understanding of the relative merits of alternative options. The user shall refer to other European Standards or to national documents for input data and detailed calculation procedures not provided by this standard. Local values for factors needed to calculate the primary energy consumption and CO2 emissions should be defined in a national annex.

prEN 15315:2005 (E) 5 1 Scope The purpose of this standard is to:  collate results from other standards that specify calculation of energy consumption within a building;  account for energy generated in the building, some of which may be exported for use elsewhere;  present a summary on tabular form of the overall energy use of the building;  specify calculation of primary energy consumption and carbon dioxide emission for the building as a whole;  establish general principles for the calculation of primary energy factors and carbon dioxide emission factors. This standard will provide:  a definition of system boundaries (e.g. building, installations, energy supply) and calculation periods;  general definition of the overall energy use (i.e. determine which services are taken into account within the system boundaries);  definition of energy terms (energy use, primary energy, etc.);  definition of the data interfaces with other standards in order to report the overall energy use of buildings;

 general procedures for taking into consideration decentralised energy production based on renewable energy and CHP (combined heat and power production), e.g. to show how on-site energy generation offsets energy demand;  identification of the energy streams across system boundaries;  principles for assessing primary energy consumption and CO2 emission of buildings (i.e. principles for determining primary energy factors and carbon dioxide emission factors);  general principles for taking into account the interactions between the different energy uses (e.g. calculation of recovered losses and gains). The objective of specifying the details of the energy performance calculation for a building is to:  underline the particularity of a project (e.g. efforts made on bioclimatic design);  show the strong and the weak points in the overall energy performance of the building and to highlight potential gains:  distinguish between thermal uses and specific electrical uses;  indicate the outputs required from related standards, in which calculation of energy consumption of services within a building are specified. This work will be coordinated with CEN/TC TC 89, TC 156, TC 169, and TC 247.

prEN 15315:2005 (E) 6 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 ISO 7345, Thermal insulation - Physical quantities and definitions prEN wi 7, Heating systems in buildings - Method for calculation of system energy requirements and system efficiencies – Part 1: General prEN wi 8, Heating systems in buildings - Method for calculation of system energy requirements and system efficiencies – Part 2.1: Space heating emission systems prEN wi 9 part 2.2.1, Heating systems in buildings - Method for calculation of system energy requirements and system efficiencies – Part 2.2.1: Space heating generation systems, Combustion systems prEN wi 9 part 2.2.2, Heating systems in buildings - Method for calculation of system energy requirements and system efficiencies – Part 2.2.2: Space heating generation systems, Heat pump systems prEN wi 9 part 2.2.3, Heating systems in buildings - Method for calculation of system energy requirements and system efficiencies – Part 2.2.3: Space heating generation systems, Thermal solar systems prEN wi 9 part 2.2.4, Heating systems in buildings - Method for calculation of system energy requirements and system efficiencies – Part 2.2.4: Space heating generation systems, The performance and quality of CHP electricity and heat (incl. on-site and micro-CHP) prEN wi 9 part 2.2.5, Heating systems in buildings - Method for calculation of system energy requirements and system efficiencies – Part 2.2.5: Space heating generation systems, The performance and quality of district heating and large volume systems prEN wi 9 part 2.2.6, Heating systems in buildings - Method for calculation of system energy requirements and system efficiencies – Part 2.2.6: Space heating generation systems, The performance of other renewables heat and electricity prEN wi 9 part 2.2.7, Heating systems in buildings - Method for calculation of system energy requirements and system efficiencies – Part 2.2.7: Space heating generation systems, Biomass combustion systems prEN wi 10, Heating systems in buildings - Method for calculation of system energy requirements and system efficiencies – Part 2.3: Space heating distribution systems prEN wi 11 part 3.1, Heating systems in buildings - Method for calculation of system energy requirements and system efficiencies – Part 3.1: Domestic hot water systems, characterisation of needs (tapping requirements) prEN wi 13, Energy performance of buildings – Energy requirements for lighting prEN wi 14, Energy performance of buildings – Calculation of energy use for space heating and cooling – Simplified method prEN wi 17, Thermal performance of buildings – Calculation of energy use for space heating and cooling – General criteria and validation procedures prEN wi 20, Ventilation for buildings – Calculation methods for energy requirements due to ventilation systems in buildings

prEN 15315:2005 (E) 7 3 Definitions and symbols 3.1 Definitions For the purposes of this document, the definitions given in EN ISO 7345 and the following terms and definitions apply: 3.1.1 building net energy (useful energy) energy supplied by ideal energy systems (no system losses are taken into account) to provide the required services for heating, cooling, ventilation, domestic hot water and lighting. Recovered losses and gains are taken into account 3.1.2 building system technical equipments for heating, cooling, ventilation, domestic hot water and lighting 3.1.3 CO2 emission factor quantity of CO2 emitted to the atmosphere per unit of energy source (kg CO2 / kWh energy source) 3.1.4 CO2 annual emission factor (system-average for an entire year) emission factor calculated by estimating the total CO2 emissions during a year and dividing that figure by the total energy delivered over the year 3.1.5 CO2 marginal emission factor (average for an entire year) emission factor applied to multi-plant generation systems and depending on the plant merit order (priority order in which the plants are put into operation as demand changes), the size of the system and the demand pattern 3.1.6 calculation period time period (time step) considered for calculation of the energy losses and gains (e.g. month, day, boosted subperiod), ref. prEN wi 7 3.1.7 co-generation (building bound) combined generation of power (electricity) and heat, where heat delivery is restricted to the buildings. The total amount of heat to be delivered by the building bound co-generation unit can be determined unequivocal. Other cases of co-generation will be considered as district heating 3.1.8 cooling process of heat extraction for thermal comfort 3.1.9 delivered energy energy supplied to the building through the system boundary to satisfy the energy requirements for heating, cooling, ventilation, domestic hot water and lighting

prEN 15315:2005 (E) 8 3.1.10 energy carrier substance or phenomenon that can be used either to produce mechanical work or heat or to operate chemical or physical processes 3.1.11 energy demand energy to be delivered by an ideal energy system (no system losses are taken into account) to provide the required service to the end user (e.g. to maintain the internal set-point temperature of a heated space) 3.1.12 energy requirements energy supplied to the technical system (system losses are taken into account) to provide the required service. Energy requirements can be specified for each subsystem (e.g. distribution, storage) and express the energy supplied to the subsystem 3.1.13 energy supplied energy made available. Energy can be supplied at different levels (e.g. termed “net energy” or “useful energy” when made available to the consumer after final conversion to provide the required service) 3.1.14 net energy energy supplied by the energy systems to provide the required services, e.g. maintaining the building at the specified internal temperature, ventilating a space, lighting a space. Recovered losses and gains are taken into account 3.1.15 overall energy use of the building energy delivered to the energy systems for heating, cooling, ventilation, domestic hot water and lighting. The overall energy takes into account the delivered energy and the energy produced inside the building and delivered back to the market 3.1.16 primary energy energy that has not been subject to any conversion or transformation process (e.g. oil in the oil fields). Primary energy may be either resource energy or renewable energy or a combination of both 3.1.17 primary energy factor primary energy divided by delivered energy, where primary energy is the energy required to supply one unit of delivered energy of the same type, taking into account the primary energy required for extraction, processing, storage, transport, generation, transformation, transmission, distribution, and any other operations necessary for delivery of energy to the building in which the delivered energy will be used. Delivery operations may call for energy of various types (e.g., electricity, oil), and each of those should be given as primary energy using the appropriate primary energy factor 3.1.18 primary resource energy factor resource energy divided by delivered energy, where resource energy is the energy required to supply one unit of delivered energy, taking into account the resource energy required for extraction, processing, storage, transport, generation, transformation, transmission, distribution, and any other operations necessary for delivery of energy to the building in which the delivered energy will be used. Any renewable energy component of the delivered energy is ignored. Delivery operations may call for energy of various types (e.g.

prEN 15315:2005 (E) 9 electricity, oil), and each of those should be given as resource energy using the appropriate primary resource energy factor. 3.1.19 recoverable losses part of the losses from the heating, cooling, ventilation, domestic hot water and lighting systems, which may be recovered to lower the energy requirements 3.1.20 recovered loss part of the recoverable losses which are recovered to lower the energy requirements 3.1.21 renewable energy energy taken from a source which is not depleted by extraction (e.g. solar, wind) 3.1.22 resource energy energy taken from a source which is depleted by extraction (e.g. fossil fuels) 3.1.23 system technical equipment providing a required service (e.g. heating system providing the required service for heating) 3.1.24 utilisation factor fraction of recoverable losses or gains that can be recovered. 3.1.25 ventilation heat loss heat loss resulting from heating of the average amount of air per time unit that enters a building or part of a building in one way or another

3.2 Symbols and units For the purposes of this document, the following symbols and units (Table 1) and indices (Table 2) apply: Table 1 : Symbols and units Symbol Name of quantity Unit E emission kg f conversion factor - Q quantity of heat, energy kWh

prEN 15315:2005 (E) 10 Table 2 : Indices aux
auxiliary h
heating energy p primary
rb recoverable c
cooling i, j
indices rp primary resource CO2
CO2 in
input to system sc cooling system
sg generation system d
distribution l
lighting sh heating system elect
electrical n
net sv ventilation system
sw domestic hot water system g
generation out
output from system w domestic hot water

Principle of the method 4.1 Overall energy use - integrated energy performance of buildings

The integrated energy performance of buildings depends on:  the building envelope and required services expressed by the building net energy (building energy requirements, building losses, building gains);  the building systems (heating system, cooling system, etc) expressed by the energy streams across the system boundary. Renewables and energy production inside the building are taken into account;  the interaction between the building envelope and the building systems;  the choice of the energy carrier (fossil fuels, renewables). The performance of the energy chain situated outside the building and related to the energy sources is taken into account in calculation of the primary energy and the CO2 emissions. Figure 1 illustrates the elements influencing the integrated energy performance of buildings.

prEN 15315:2005 (E) 11

Figure 1 — Elements influencing the integrated energy performance of buildings (example).

The following assumptions apply for calculation of the integrated energy performance of buildings: a) System boundary The building envelope constitutes the system boundary. Inside the system boundary, only the defined uses (heating, cooling, ventilation, domestic hot water and lighting) are taken into account. Other uses like electrical consumption for household devices (TV sets, refrigerators, etc.) are not taken into account. Energy can be imported or exported through the system boundary. All the energy streams across the system boundary are identified. Some of these energy streams can be quantified by meters (e.g. gas, electricity, district heating and water) in case the system devices (boiler, chiller, cooling tower, etc.) are located outside the building envelope. If the system devices form part of the building system, they are considered to be inside the system boundary. For active solar energy systems, the generation devices (solar panels: thermal and photovoltaic) are considered as located just outside the system boundary. The auxiliary energy needed to supply the energy from the source (solar panel) to the building is considered inside the system boundary, but the incident solar radiation on the panels is not taken into account, because it does not cross the system boundary (see figure 2). Passive solar radiation (the incident solar radiation entering through the openings of the building) is taken into account because it crosses the system boundary.

prEN 15315:2005 (E) 12

Figure 2 — System boundary: Examples of energy streams across system boundary Assessment of energy performance shall not be limited to the buildings where the energy consumption takes place. A holistic approach calls for a framework that defines end-user savings as savings carried out along the entire energy chain (e.g. district heating and cooling). The performance of the energy chain situated outside the system boundary is taken into account in calculation of primary energy and CO2 emissions. b) Calculation period The objective of the calculation is to determine the annual overall energy use, primary energy and CO2 emission. This may be done in one of the following two different ways:  using annual data for the system operation period and performing the calculations using annual average values;  dividing the year into a number of calculation periods (e.g. months, weeks) and performing the calculations for each period using period-dependent values and sum up the results for all the periods over the year. c) Interactions between the building envelope and the building system - Calculation of recovered losses and gains The interactions between the different energy uses (heating, cooling, ventilation, etc.) are taken into account by calculation of recovered losses which could have a positive (e.g. heat) or negative (e.g. cooling) impact on the energy performance of the building. Two approaches are admitted for calculation of the building net energy (see figure 3):  a holistic approach considering all recoverable losses and gains (in the building part and in the system part). Calculation of the recovered losses for heating and cooling is defined in prEN wi 14. As the recoverable system losses depend on the building net energy, and the building net energy depends on the recovered system losses, an iteration is required:

prEN 15315:2005 (E) 13  calculate the building net energy, taking into account only the recovered losses and gains of lighting and passive solar radiation and internal losses and gains (ignore the recoverable system losses);  perform the system calculation and determine the recoverable system losses;  calculate again the building net energy, taking into account all recoverable losses and gains (in the building part and in the system part);  perform the system calculation again.  a simplified approach taking into account recoverable losses and gains excluding the recoverable losses of the heating, cooling, ventilation and domestic hot water systems. The recovered system heat losses are deducted from the loss of each considered part. This will avoid iterations:  calculate the building net energy, taking into account only the recovered losses and gains of lighting and passive solar radiation and internal losses and gains (ignore the recoverable system losses);  perform the system calculation and determine the recoverable system losses;  determine the recovered system losses (using a specific utilisation factor);  deduct the recovered system losses from the energy requirements of the subsequent system (e.g. fuel input) It is allowed to take into account other recoverable system losses (e.g. emission) when calculating the building net energy. For complex systems (e.g. heating and cooling installations) the holistic approach is recommended. NOTE: The simplified approach is already used in some national building regulations. The recovered system losses, e.g. for distribution, are calculated using a specific utilisation factor, taking into account the building net energy and only the recoverable system losses of the considered part. The recovered system loss is subtracted from the system loss. When calculating the recovered system loss for generation, the recovered loss is deducted from the fuel input without taking into account the generation efficiency.

Figure 3 — Calculation of recovered losses: holistic and simplified approach

prEN 15315:2005 (E) 14 d) Considering energy streams across the system boundary The conventions taken for calculation of energy streams across the system boundary are shown in figure 4. The renewable energy flows have to be specified. The building electricity production and the electricity consumption are considered separately. The electricity consumption is not deducted from the electricity production. The electricity production is considered with a negative value. NOTE: The electricity consumption is not deducted from the electricity production because consumption and production may not occur at the same time. The possibility should be given in the calculation method to take this into account, for example by applying different primary energy conversion factors for the consumption and the production.

CO2 emissions depend strongly on the considered time period. Simple deduction of the energy consumption from the energy production would not take this fact into account and would come out with a lower performance for alternative systems in feasibility studies. If the renewables are not taken into account when calculating the delivered energy, the contribution of the renewables will not be visible in the calculation.

Figure 4 — Energy streams across system boundary and decentralised electricity production conventions e) Calculation procedure and reporting

The calculation direction is from the losses to the source (e.g. from the building net energy to the primary energy). Specific electrical uses (lighting, auxiliary) and thermal uses are reported separately. The calculation procedure is in line with the definitions given in the European Performance Building Directive. The amount of energy is calculated by taking into account insulation, technical and installation characteristics and energy generation inside the buildings. An overview of the different parameters influencing the integrated energy performance of buildings, expressed as primary energy and CO2 emissions, is given in the tables of annex B.

prEN 15315:2005 (E) 15 4.2 Energy use and building net energy The total calculated energy use of a building shall comprise the energy used for the following purposes:  heating;  cooling;  ventilation;  domestic hot water;  lighting. Calculation of energy use and net energy shall be reported as shown in Table 3. The necessary inputs are (calculated according to the referenced prENs in Table 3): Qh

Heat demand for space heating Qnh
Net heat demand for space heating Qc
Energy demand for space cooling Qnc
Net energy demand for space cooling
Heat demand for domestic hot water Ql
Energy use for lighting
Table 3 : Energy use and building net energy
C1 C2 C3
Heating including ventilation Cooling including ventilation Domestic hot water
Lighting (specific electrical use)L1 Energy losses (or needs) of the building Qh
(prEN wi 14) Qc
(prEN wi 14) QW
(prEN wi 11)
(prEN wi 13) L2 Building net energy Qnh
(prEN wi 14) Qnc
(prEN wi 14) QW
(prEN wi 11)
(prEN wi 13)

4.3 Calculation of the energy streams across the system boundary Calculation of the energy streams across the system boundary is done in the following steps: a) report the system losses (thermal and specific electrical) without building generation devices (see 4.3.1); b) report the generation system losses (see 4.3.2); c) report the energy streams across the system boundary (see 4.3.2). NOTE: The energy requirements of the building distribution systems are determined at the connecting point of the building generation systems including renewables. This separation is useful, because supplied renewable energy cannot simply be subtracted from the heat demand. The heat demand does not take into account different system losses, which can be very important (e.g. domestic hot water distribution). The part of energy produced by solar systems should be calculated considering heat demand and the system losses (e.g. distribution) in order to obtain proper results.

prEN 15315:2005 (E) 16 4.3.1 System losses (thermal and specific electrical) without building generation devices The system losses shall be reported according to Table 4. The necessary inputs are (calculated according to the referenced prENs in Table 4): Specific electricity consumption: Qsh,aux

Auxiliary consumption of the heating system Qsv,aux
Auxiliary consumption of the ventilation system Qsc,aux
Auxiliary consumption of the cooling system Qsw,aux
Auxiliary consumption of the domestic hot water system

Thermal system losses If the simplified approach for calculation of the recovered system losses is chosen (according to 4.1 c)), then the thermal system losses indicated in Table 4 are the net system losses, because the recovered system losses have already been taken into account and are deducted from the thermal losses according to the specific standards. The thermal system losses are the sum of the emission losses, storage losses and distribution losses. Qsh

Thermal system losses of the
...

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