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

[4] is the delivered energy, represented separately for each energy carrier,
inclusive of auxiliary energy, used by heating, cooling, ventilation, hot water
and lighting systems, taking into account renewable energy sources and cogeneration.
This may be expressed in energy units or in units of the energyware
(kg, m³, kWh, etc)
[5] is renewable energy produced on the building premises
[6] is generated energy, produced on the premises and exported to the market;
this can include part of [5]
[7] represents the primary energy usage or the CO 2 emissions associated with
the building
[8] represents the primary energy or emissions associated with on-site generation
that is used on-site and so is not subtracted from [7]
[9] represents the primary energy or CO 2 savings associated with exported energy,
which is subtracted from [7]
The overall calculation process involves following the energy flows from the left to
the right of the model above.
The model above is a schematic illustration and is not intended to cover all possibilities.
For example, a ground-source heat pump uses both electricity and renewable
energy from the ground. And electricity generated on-site by photovoltaics
could be used within the building, it could be exported, or a combination of these.
Renewable energy sources like biomass are included in [7], but are distinguished
from non-renewable energy carriers by low CO 2 emissions. In the case of cooling,
the direction of energy flow is from the building to the system.
Energy demand and
supply model
The BAC functions according to EN 15232 are based on the energy demand and
supply model for a building as shown below.
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