Bsi bs en 15316 3 3 2007 (2008)

untitled BRITISH STANDARD BS EN 15316 3 3 2007 Heating systems in buildings — Method for calculation of system energy requirements and system efficiencies — Part 3 3 Domestic hot water systems, genera[.]

This British Standard was

published under the authority

of the Standards Policy and

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.

Amendments/corrigenda issued since publication

EUROPÄISCHE NORM

ICS 91.140.10

English Version

Heating systems in buildings - Method for calculation of system

energy requirements and system efficiencies - Part 3-3:

Domestic hot water systems, generation

Systèmes de chauffage dans les bâtiments - Méthode de

calcul des besoins énergétiques et des rendements des

systèmes - Partie 3-3 : Systèmes de production d'eau

chaude sanitaire, génération

Heizungsanlagen in Gebäuden - Verfahren zur Berechnung der Energieanforderungen und Nutzungsgrade der Anlagen

- Teil 3-3: Trinkwassererwärmung, Erzeugung

This European Standard was approved by CEN on 18 August 2007.

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

C O M I T É E U R O P É E N D E N O R M A L I S A T I O N

E U R O P Ä IS C H E S K O M IT E E FÜ R N O R M U N G

Management Centre: rue de Stassart, 36 B-1050 Brussels

Contents

Foreword 4

Introduction 6

1 Scope 7

2 Normative references 7

3 Terms and definitions 7

4 Symbols, units and indices 10

5 Energy output of the domestic hot water generation sub-system 11

5.1 General 11

5.2 Domestic hot water systems with a single heat generator 11

5.3 Domestic hot water systems with multiple heat generators 12

5.3.1 General 12

5.3.2 Domestic hot water systems with different types of heat generators in a series configuration 12

5.3.3 Domestic hot water systems with multiple heat generators in a parallel configuration 12

6 Indirectly heated hot water storage vessel 13

7 Primary circulation pipes 14

7.1 General 14

7.2 Thermal losses by a simple estimation method 14

7.3 Thermal losses by a detailed calculation method 14

8 Direct heated domestic hot water generation devices 14

8.1 General 14

8.2 Heat generation systems in single-family dwellings 15

8.3 Heat generation systems others than for single-family dwellings 16

8.3.1 Oil and gas fired boilers 16

8.3.2 Direct gas fired domestic storage water heater 16

8.3.3 Direct electrical heated domestic storage water heaters 16

8.3.4 Alternative generators 17

9 Auxiliary energy 17

9.1 Total auxiliary energy consumption 17

9.2 Auxiliary energy consumption for primary circulation pumps 18

9.3 Auxiliary energy consumption for direct heated domestic hot water generation devices 18

10 Recoverable heat losses, recovered heat losses and unrecoverable heat losses 18

Annex A (informative) Calculation of thermal loss from a gas or oil fired boiler in systems other than for single family dwellings 20

A.1 Calculation of total boiler thermal loss 20

A.2 Calculation of heat loss during boiler operation 20

A.3 Calculation of stand-by heat loss 21

A.3.1 General 21

A.3.2 Average boiler temperature during a stand-by period 21

A.3.3 Load factor of a boiler 21

A.3.4 Auxiliary energy consumption for a boiler 22

A.3.5 Nominal output efficiency of a boiler 22

Annex D (informative) Thermal loss from an electrical heated domestic storage water heater (with

timed power on) 27 Bibliography 31

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 prCEN/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

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

Introduction

This European Standard is one of a number of standards that together describe methods for calculation of system energy requirements and system efficiencies related to domestic hot water systems In particular this European Standard specifies methods for calculation of the input energy requirements and energy losses of the generation units

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

Only the calculation methods are normative Values necessary to complete the calculations should be given in

a national annex

1 Scope

This European Standard is part of a set of standards covering the methods for calculation of system energy requirements and system efficiencies of heating systems in buildings In particular this standard is one of a number of standards dealing with domestic hot water systems

The scope of this specific part is to standardise the methods for calculation of:

 thermal losses from the domestic hot water generation system;

 recoverable thermal losses for space heating from the domestic hot water generation system;

 auxiliary energy of the domestic hot water generation systems

These values are input data for calculation of the overall energy use according to prEN 15603 and

EN 15316-3-2, Heating systems in buildings — Method for calculation of system energy requirements and system efficiencies — Part 3-2 Domestic hot water systems, distribution

prEN 50440, Efficiency of domestic electrical storage water-heaters

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply

3.1

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 1 This includes energy for fans, pumps, electronics etc Electrical energy input to a ventilation system for air transport and heat recovery is not considered as auxiliary energy, but as energy use for ventilation

NOTE 2 In EN ISO 9488, the energy used for pumps and valves is called "parasitic energy"

3.2

building

construction as a whole, including its envelope and all technical building systems, for which energy is used to condition the indoor climate, to provide domestic hot water and illumination and other services related to the use of the building

NOTE The term can refer to the building as a whole or to parts thereof that have been designed or altered to be used separately

3.3

calculation period

period of time over which the calculation is performed

NOTE The calculation period can be divided into a number of calculation steps

3.4

domestic hot water heating

process of heat supply to raise the temperature of the cold water to the intended delivery temperature

3.5

energy need for domestic hot water

heat to be delivered to the needed amount of domestic hot water to raise its temperature from the cold network temperature to the prefixed delivery temperature at the delivery point, not taking into account the technical building thermal systems

3.6

energy use for space heating or cooling or domestic hot water

energy input to the space heating or cooling system or the domestic hot water system to satisfy the energy need for space heating or cooling (including dehumidification) or domestic hot water, respectively

NOTE If the technical building system serves several purposes (e.g space heating and domestic hot water), it can be difficult to split the energy use into that used for each purpose It can be indicated as a combined quantity (e.g energy need for space heating and domestic hot water)

3.7

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 1 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 2 According to ISO 13602-2, the gross calorific value is preferred to the net calorific value

NOTE 3 The net calorific value does not take into account the latent heat of condensation

3.8

heating or cooling season

period of the year during which a significant amount of energy for heating or cooling is needed

NOTE The season lengths are used to determine the operation period of technical systems

3.9

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)

3.10

part load operation

operation state of the technical system (e.g heat pump), where the actual load requirement is below the actual output capacity of the device

3.11

recoverable system thermal loss

part of a 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

NOTE This depends on the calculation approach chosen to calculate the recovered gains and losses (holistic or simplified approach)

3.12

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

system thermal loss

thermal loss from a technical building system for heating, cooling, domestic hot water, humidification, dehumidification, or ventilation or lighting that does not contribute to the useful output of the system

NOTE 1 A system loss can become an internal heat gain for the building, if it is recoverable

NOTE 2 Thermal energy recovered directly in the subsystem is not considered as a system thermal loss but as heat recovery and directly treated in the related system standard

NOTE 3 Heat dissipated by the lighting system or by other services (e.g appliances of computer equipment) is not part

of the system thermal losses, but part of the internal heat gains

technical building system

technical equipment for heating, cooling, ventilation, domestic hot water, lighting and electricity production composed by sub-systems

NOTE 1 A technical building system can refer to one or to several building services (e.g heating system, space heating and domestic hot water system)

NOTE 2 Electricity production can include cogeneration and photovoltaic systems

3.17

technical building sub-system

part of a technical building system that performs a specific function (e.g heat generation, heat distribution, heat emission)

4 Symbols, units and indices

For the purposes of this document, the following symbols and units (Table 1) and indices (Table 2) apply

Table 1 — Symbols and units

t time, period of time s

Q quantity of heat, energy J

X coefficient of relative quantity of energy delivered

versus maximum energy stored -

Table 2 — Indices

amb ambiant ls loss p pipe

avg average max maximum sby stand-by

del delivered meas measured sol solar

dis distribution mn arithmetic mean st storage

e external nd need Tot total

em emission nom nominal ve ventilation

gen generation off off W domestic hot water

in input to system on on x indices

ind independent out output from system

int internal p primary

5 Energy output of the domestic hot water generation sub-system

5.1 General

The heat generator for a domestic hot water system shall provide the energy required for meeting the energy

need for domestic hot water and for compensating the losses in the other sub-systems (e.g distribution)

The energy requirement on the heat generator is given by:

ls p W ls st W ls dis W W

Q

If the heat generator or generators also provide space heating, the performance of the heat generator shall be

calculated separately for operation during the summer period, when there is no space heating demand, and

operation during the winter period, when both space heating and domestic hot water is being provided

5.2 Domestic hot water systems with a single heat generator

If a single heat generator is applied, the total generation output has to be provided from that heat generator

5.3 Domestic hot water systems with multiple heat generators

5.3.1 General

If more than one heat generator is applied to provide the required heat energy for domestic hot water, the

contribution from each heat generator is calculated on the basis of the nominal output of each individual heat

generator

If any or all of these heat generators have separate primary pipe circuits, the primary pipe losses and the

auxiliary energy consumption should be calculated separately for each circuit

5.3.2 Domestic hot water systems with different types of heat generators in a series configuration

If the domestic hot water is heated by different types of heat generators in a series configuration, the

contribution of each individual heat generator shall be determined Calculations are to be performed in the

sequence of application of the heat generators for energy generation

NOTE Normally it is assumed, that the domestic hot water can be heated by a maximum of three heat generators:

pre-heating by e.g solar panels, base heating and supplementary heating to meet the peak load

If heat energy is supplied to the domestic hot water system from other types of appliances (e.g exhaust air

heat pump, see EN 15450 and prEN 15316-4-2), only the remaining heat demand is covered by the

supplementary heat generator (e.g a boiler)

5.3.3 Domestic hot water systems with multiple heat generators in a parallel configuration

If more than one heat generator is applied in a parallel configuration to provide the required heat energy for

domestic hot water, the proportional contribution

α

nominal output of that unit to the total nominal output of the installation available for heating the domestic hot

water

out gen W

i W gen nom i

i nom gen W out

gen W i gen W

, , ,

, , , ,

, , , ,

For heating the domestic water, a number of heat generators (e.g solar panel, boiler, heat pump, or electrical

ancillary heating) can be available The total heat requirement for all loads shall correspond to the total heat

output of all heat generators:

∑

k j

Q

If more than one heat generator is applied, the total heat demand of the distribution system

Q

distributed amongst the available heat generators The calculations are to be performed independently for

6 Indirectly heated hot water storage vessel

The storage thermal loss from an indirectly heated hot water storage vessel can be obtained from the

stand-by heat loss of the vessel The total heat dissipated from the storage vessel over the time period considered is

quantified as a loss

The storage thermal loss is calculated from the stand-by heat loss with adjustment to actual temperature

difference as follows:

sby st W sby

st W

avg amb avg st W

, ,

,

,

,

) (

Q

The weekly, monthly or annual thermal losses are obtained by multiplying the thermal loss per day by the

appropriate number of days

The stand-by heat loss of the storage vessel has to be measured in accordance with a European Standard or

national standard, e.g EN 12897, appropriate for the vessel size and type The measured stand-by heat loss

is based on the actual temperatures during the period of operation The standard to be used for the

measurement shall be specified in a national annex

If the stand-by heat loss of the storage vessel is not available, a value can be calculated on the basis of an

equation of the form;

z st W sby

Values for the constanst x ,

y

z

The stand-by heat loss from older storage vessels can be estimated in a similar way, where values for the

constants x ,

y

z

stand-by heat loss based on storage volume and insulation type and thickness

If the hot water storage vessel is located within the heated space of the building, part of the storage thermal

loss may be recovered (see Clause 10)

Connecting pipes to the storage water heater may increase the storage thermal loss, particularly if the pipes

are not insulated These additional losses are caused by circulation set up in the connecting pipes between

the hot water in the storage vessel and cooler water in the pipes away from the vessel If these losses are to

be taken into account, the method shall be given in a national annex

7 Primary circulation pipes

7.1 General

Where the domestic hot water is supplied from an indirectly heated hot water storage vessel, the heat energy

is supplied from a separate heat generator The hot water storage vessel may be located adjacent to or remote from the heat generator

Thermal losses

Q

 a simple estimation method;

 a detailed calculation method

The hot water storage vessel may be incorporated into the heat generator appliance and thus the thermal loss

of the primary circulation pipes may be taken into account by the overall appliance efficiency measurements For gas appliances with a hot water storage vessel incorporated and intended to be installed in single family dwellings, measurements according to EN 13203-2 include the thermal loss of the primary circulation pipes

7.2 Thermal losses by a simple estimation method

A simple method for estimating the thermal losses from primary circulation pipes is to use a fixed representative value For application of this method, appropriate values shall be given in a national annex

7.3 Thermal losses by a detailed calculation method

For this detailed calculation method the methods for calculation of thermal losses from pipes given in

EN 15316-3-2 shall be followed for the primary circulation pipes

Calculation of the thermal losses from the primary circulation pipes should be based on the actual length of the pipes, if available If the detailed pipe network plan is not available, representative values for the pipe lengths can be applied These values shall be given in a national annex

8 Direct heated domestic hot water generation devices

8.1 General

Energy labelling legislation requires efficiency measurements to be obtained for domestic hot water heat generators to be applied in single-family dwellings These requirements are intended to be independent of the fuel source and heat generator type, and are therefore treated separately in 8.2

Where domestic hot water generation systems are installed in buildings providing multi-family accommodation

or in commercial buildings, the efficiency of the domestic hot water generation is based on the appliance performance standards appropriate for that appliance technology (see 8.3)

8.2 Heat generation systems in single-family dwellings

The domestic hot water generation efficiency for heat generation systems in single-family dwellings is

intended to be required to meet energy labelling legislation Standards developed to show compliance with the

corresponding directive are to incorporate test procedures against three common domestic hot water tapping

programs

The results of such tests provide domestic hot water generation efficiency based on each of the tapping

programs If the appliance is not intended to provide the domestic hot water requirement corresponding to all

three tapping programs, this is to be identified in the appliance specification, containing test results only for the

applicable hot water tapping programs

For this method, it is not necessary to have results from all three tapping programs The method is based on

an efficiency value corresponding to the average tapping program and either the higher tapping program or

the lower tapping program, depending on whether the domestic hot water energy requirement is above or

below the energy requirement corresponding to the average tapping program

The domestic hot water generation efficiency related to the actual domestic hot water use can be obtained by

linear interpolation as follows:

For domestic hot water use below the average, i.e

Q

< Q

< Q

) 042

, 21 (

* ) (

* 2 074 ,

* ) (

* 8 047 ,

Q

If

Q

< Q

Q

Q

If

Q

> Q

out

gen

8.3 Heat generation systems others than for single-family dwellings

8.3.1 Oil and gas fired boilers

The total thermal loss from a boiler is based on:

 nominal output efficiency

η

 stand-by heat lossQ W,gen,ls,sby;

 nominal heat output

Q

These values have to be determined by measurements, e.g in accordance with EU Directive 92/42, EN 304,

EN 297, EN 483, EN 656, EN 625 (for combination boilers), or EN 677 (for condensing boilers)

If measurements are not available, fixed default values shall be given Default values shall be provided in a national annex

The calculation method is given in Annex A

A national annex may specify default values if specific test results are not available

For older boilers, for which the efficiency and the stand-by heat loss may not be known, values may be given

in a national annex

8.3.2 Direct gas fired domestic storage water heater

The efficiency of a direct gas fired domestic storage water heater should be obtained from tests in accordance with EN 89

If no efficiency values are available, minimum values may be provided in a national annex These values should not be lower than the default values given in Annex B

The energy required to maintain the hot water temperature is assumed to be equal to the heat loss to the surroundings This value should be obtained from the test method specified in EN 89 and may be quoted by the manufacturer

If no value is available, a default value shall be used The default value is calculated on the basis of the maximum value specified in EN 89 for the maintenance energy requirement This is assumed to be 20 % less than the maximum value allowed

The calculation method is described in Annex B

For older systems, where the manufacturer’s data is not available and measurements cannot be made, the values to be used shall be given in a national annex

8.3.3 Direct electrical heated domestic storage water heaters

8.3.3.1 General

Electrical heated domestic storage water heaters may be heated continuously or heated for a defined period

of the day