UK Part L2A 2010 DSM
Heating Seasonal eff.
You must set the seasonal efficiency of the heat source serving the system. If the design data is not
available, the default value can be used. This will compare unfavourably with the national system
efficiency.
As you work through the NCM wizard, you will notice the Heating SCoP at the bottom of screen will
change depending on your selections. The Heating SCoP defines the overall seasonal efficiency of the
heating system, including the heat source efficiency and the distribution losses. When you click “OK” and
then “Save and Apply NCM parameters”, these values will be applied to the main Apache Systems
window.
You can make changes to the heating efficiency directly in the Apache Systems window, however be
aware that if you change the generator seasonal efficiency in the Apache Systems window, the SCoP will
not change. You will also need to edit the SCoP so that the delivery efficiency stays constant. Note that
you cannot directly edit the delivery efficiency. You must edit either the generator seasonal efficiency or
the heating SCoP to edit the delivery efficiency.
UK Part L2A 2010 DSM Navigator
UK Part L2A 2010 DSM
Generator seasonal efficiency (GSE)
The seasonally averaged efficiency of the heat generator (eg boiler).
Heating delivery efficiency (HDE)
The seasonally averaged ratio of delivered heat to the output from the heat generator. This allows for
distribution losses and factors such as fan gain and imperfect control.
System co-efficient of performance (SCoP)
Seasonal coefficient of performance of the heating system. The ratio of delivered heating to total energy
used by the heating system. ‘Delivered’ means this figure includes an allowance for distribution losses.
Relation between heating system parameters:
The heating system parameters are related by
SCoP = GSE * HDE
UK Part L2A 2010 DSM Navigator