ISO 13675:2013 pdf download.Heating systems in buildings — Method and design for calculation of the system energy performance — Combustion systems (boilers)
4 Alignment of the parts of the heating system standards
4.1 Physical factors taken into account
The calculation method of the generation sub-system takes into account heat losses and/or recovery due to the following physical factors:
a) heat losses to the chimney (or flue gas exhaust) and through the envelope of the storage tank and the generator(s) during total time of generator operation (running and stand-by);
b) heat losses through the generator(s) envelope during total time of generator operation (running and stand-by);
c) auxiliary energy.
The relevance of these effects on the energy requirements depends on:
— type of heat generator(s);
— type of buffer tank(s);
— location of heat generator(s);
— type of buffer tank(s);
— part load ratio;
— operating conditions (temperature, control, etc.);
— control strategy (on/off, multistage, modulating, cascading, etc.).
4.2 Input quantities from other parts of the heating system standards
If a zone is heated and cooled in the same month, it shall be determined which occurred more often and the appropriate temperature used.
The daily operation is taken into account by the heating time (operating hours/period of duration), t H,op .
The assumption is made that there is always only one user. Where there are a number of different loads,a differentiation must be made between the individual requirements for each case.
Only if the useful heat demand Q H,dis,in > 1 kWh (in the calculation interval) is heating necessary.
4.3 Output quantities for other parts of the heating system standards
The calculation of the values takes place basically for the zones defined in ISO 13790.
If a number of parts of systems are contained in the various process domains then the values are to be added together for further analysis.
Here it is to be taken into account that the heating data are to be related to the gross calorific value.
In the following sections the thermal and auxiliary energy components of the different process domains are determined for further analysis.
4.4 Heat balance of the generation sub-system, including control of heat generation
Figure 1 shows the calculation inputs and outputs of the generation sub-system.
NOTE For commercial purpose, Figure 1 can be simplified by grouping the different type of losses.
Key
SUB Generation sub-system balance boundary
HF Heating fluid balance boundary (see Formula 1)
Q H,gen,out Generation sub-system heat output [input to distribution sub-system(s)]
E H,gen,in Generation sub-system fuel input (energyware)
W H,gen Generation sub-system total auxiliary energy
Q H,gen,aux,rvd Generation sub-system recovered auxiliary energy
Q H,gen,ls Generation sub-system total thermal losses
Q H,gen,ls,rbl Generation sub-system thermal loss recoverable for space heating
Q H,gen,ls,rbl,th Generation sub-system thermal loss (thermal part) recoverable for space heating
Q H,gen, rbl,aux Generation sub-system recoverable auxiliary energy
Q H,gen,ls,nrbl,th Generation sub-system thermal loss (thermal part) non recoverable
Q H,gen,nrbl,,aux, Generation sub-system non recoverable auxiliary energy
NOTE Figures shown are sample percentages.
where
E gen,in is the energy input of the generation sub-system (fuel input) (in the calculation interval), in kWh;
Q gen,out is the energy supplied to the distribution sub-systems (e.g. space heating and domestic hot water) (in the calculation interval), in kWh;
Q gen,aux,rvd is the auxiliary energy recovered by the generation sub-system (e.g. pumps, burner fan, etc.) (in the calculation interval), in kWh;
Q gen,ls is the thermal losses of the generation sub-system (e.g. through the chimney, generator envelope, etc.) (in the calculation interval), in kWh;
Q gen,ren is the regenerative energy contribution (in the calculation interval), in kWh.
NOTE 1 Q gen,ls takes into account flue gas and generator envelope losses, part of which may be recoverable for space heating according to location of the generator. See 5.2.2.
NOTE 2 Generally biomass boilers are not designed for controlling the emission part of heating systems.
NOTE 3 Q gen,ren is normally not used with boilers.ISO 13675 pdf download.ISO 13675-2013 pdf download
