BS/EN 15316-1-2017 pdf download.Energy performance of buildings — Method for calculation of system energy requirements and system efficiencies Part 1: General and Energy performance expression, Module M3-1, M3-4, M3-9, M8-1, M8-4.
5 Description of the methods
S.1 General description of the calculation method
5.1.1 CalculatIon direction
The calculation direction is from the energy needs to the source (e.g. from the building energy needs to the primary energy). The calculation direction is the opposite of the energy flow in the system.
If a priority is defined between services or sub-systems these services or sub-systems are calculated according to the priorities.
The calculation structure shall follow the actual structure of the heating systems.
Thermal energy and auxiliary energy used by the heating and 1)11W systems are calculated separately.
5.1.2 OperatIng conditions
lor each sub-system the operating conditions (e.g. temperatures, mass flows) are calculated according to the related operating conditions modules (see Annex C). The calculation of operating conditions takes into account controls (control identifier).
Only if’ the sub-systems arc separated by a node they can have dilicrent operating conditions.
The calculation in the heating, domestic hot water or other sub-system standards applies to a specific part of the technical system with its specific operating conditions (e.g. pipe length, temperatures, etc.).
In complex buildings with complex technical systems there are more specific parts because there are more than one heating system zone and therefore more than one emission, distribution and generation sub-systems. For a technical system with several load circuits it is necessary to know the specific operating conditions of each part (e.g. the demand in each load circuit and the corresponding temperatures) and to apply the sub-systems standards accordingly to each of them.
lnput versus output” naming is related to the energy flow.
The calculation direction is the opposite of the energy flow (an energy flow” input is a calculations output).
To make the distinction clear it is recommended to specify it (e.g. “floW’ input, calculation” output). The operating conditions may for each sub-system include:
— the supply temperatures 8X-Y•in/out•sup
— the return temperatures 0x;Y;in/out;iet
— the average temperatures t9X.yqn/ou.ayg;
5.13 Maximum heat supply and power check
Often emitters are oversized whilst generation devices may be sized on average power. Therefore it Is likely that the limitation of the power will not be on the emission sub-systems (an exception may be floor heating) but on the generation.
The maximum heat supply may also depend on the internal or external operating conditions (e.g. heat pumps).
For the monthly method and some special generators (like heat pumps) the bin niethod will be used to check if the generator is able to supply the requested heat. The needed running time to supply the heat will be compared to the effective bin time.
For the monthly method there should be a maximum average load (e.g. 70…80 %) because it Is not likely that the installation may run full load for the whole month.
For the hourly method, the check of the heat supply Is done for the emission and generation subsystem. Different possibilities arc given to deal with a lack of energy supply:
— to add the missing energy production to the sub-system output (emission, generation) of the next time step. lithe sub-system is not able to provide the requested energy after a defined number of time steps, then the calculation is stopped and the sizing of the generation sub-system should be reviewed by the designer,
— to calculate the variation of the Internal temperature.
If there is lack of energy supply, the calculation will re-boucle at the emitter output calculation with the heat supply requested at the emitter output mintis the difference of the requested energy supply and the maximum heat supply of the sub-system in the calculation interval.BS/EN 15316-1-2017 pdf download.

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