Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols, units and indices
5 Domestic hot water system characteristics
5.1 General
5.2 Single zone and single system
5.3 Single zone and multiple systems
5.4 Multiple zones with single system
6 Distribution thermal losses
6.1 Total distribution thermal losses
6.2 Thermal losses from individual distribution
pipe section
6.2.1 General
6.2.2 Thermal losses from pipes based on dwelling
area
6.2.3 Thermal losses from pipes based on pipe
lengths and number of tappings per day
6.2.4 Thermal losses from pipes based on pipe
lengths and distribution efficiencies
6.2.5 Thermal losses from pipes based on pipe
lengths and tapping profiles
6.2.6 Thermal losses from pipes based on pipe
lengths and average temperature
6.2.7 Heat energy lost due to wasted hot water
6.2.8 Time periods
6.3 Thermal losses from circulation loop
6.3.1 General
6.3.2 Thermal losses from circulation loop based
on pipe length and a fixed value of heat loss
6.3.3 Thermal losses from circulation loop based
on a physical approach
6.3.4 Additional thermal losses from circulation
loop during periods of no circulation
6.3.5 Total thermal loss from circulation loop
6.4 Thermal losses due to accessories
6.5 User outlets
7 Auxiliary energy
7.1 Total auxiliary energy consumption
7.2 Auxiliary energy consumption for ribbon heating
7.3 Auxiliary energy consumption for pumps
7.3.1 General
7.3.2 Simplified method
7.3.3 Detailed calculation method
8 Recoverable, recovered and unrecoverable system losses
Annex A (informative) Calculation of thermal losses from pipes
based on pipe lengths and the number
of tappings per day
Annex B (informative) Calculation of thermal losses from pipes
based on pipe lengths and distribution
efficiencies
Annex C (informative) Calculation of thermal losses from pipes
based on pipe lengths and tapping profiles
Annex D (informative) Calculation of thermal losses from
circulation loop
D.1 Calculation of thermal losses based on pipe length
D.2 Thermal losses based on a detailed calculation method
D.2.1 General
D.2.2 Determination of length of pipe sections
D.2.3 Determination of heat transfer coefficients
D.2.4 Tabulated method for calculation of linear
thermal transmittance
D.2.5 Determination of average ambient temperature
D.2.6 Determination of average hot water temperature
of pipe section
Annex E (informative) Calculation of thermal losses from
user outlets
Annex F (informative) Calculation of auxiliary energy requirement
of a circulation pump
F.1 Simplified method for calculation of auxiliary energy
requirement of a circulation pump
F.2 Detailed method for calculation of auxiliary energy
requirement of a circulation pump
F.2.1 Hydraulic energy requirement
F.2.2 Hydraulic power required by the pump
F.2.3 Duration of the provision of domestic hot water
F.2.4 Pump performance coefficient
F.2.5 Intermittent pump operation
F.2.6 Expenditure value coefficient
F.3 Auxiliary energy recoverable factor
Bibliography