Building automation – impact on energy efficiency - Siemens ...

4.3.2 Factor-based calculation procedure of the BACS <strong>impact</strong>
on the energy performance of buildings (BACS
factor method)
General
The BACS factor method described here has been established to allow a simple
calculation of the <strong>impact</strong> of building <strong>automation</strong>, control and management functions
on the building’s energy performance. The following figure 2 illustrates
how to use this approach.
Remarks
Arrows (( ) illustrate only the calculation process and do not represent energy and/or mass flows
1) Delivered energy is the total energy, expressed per energy carrier (gas, oil, electricity etc.)
a) Thermal energy = overall energy use for heating, DHW, cooling, and ventilation
b) Electricity energy = overall energy use for auxiliary equipment and lighting
c) Specific energy use for heating, DHW or cooling
d) Specific energy use for auxiliary equipment or lighting
The BAC factor method gives a rough estimation of the <strong>impact</strong> of BACS and
TBM functions on thermal and electric energy demand of the building according
to the efficiency classes A, B, C and D. The BACS factor method is specially
appropriated to the early design stage of a building because there is no special
information needed about any specific control and <strong>automation</strong> function just the
recent (if it is an existing building) or reference building <strong>automation</strong> class and
the classification of the building as expected or predefined.
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