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

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

AUTOMATIC CONTROL

1 HEATING CONTROL BT Reason for energy savings

1.3 Control of distribution network hot water temperature (supply or

return)

Similar function can be applied to the control of direct electric

heating networks

0 No automatic control The highest design temperature of all consumers is

continuously provided in distribution, resulting in

significant energy losses under part load conditions.

1 Outside temperature-compensated control

Action lower the mean flow temperature

2 Demand-based control

E.g. based on indoor temperature; actions generally lead

to a decrease of the flow rate

1.4 Control of distribution pumps in networks

The controlled pumps can be installed at different levels in

the network

Distribution temperature is controlled depending on the

outside (corresponding to the probable temperature

demand of the consumers). This reduces energy losses

under part load conditions.

Distribution temperature depending on the room

temperature (controlled variable). It considers heat

sources in the room as well (solar irradiance, people,

animals, technical equipment). Keeps energy losses under

part load conditions at an optimum (low).

0 No automatic control No savings, since electrical power for the pump is drawn

continuously.

1 On off control

To reduce the auxiliary energy demand of the pumps

2 Multi-stage control

To reduce the auxiliary energy demand of the pumps

3 Variable speed pump control

With constant or variable Δp and with demand evaluation to

reduce the auxiliary energy demand of the pumps

1.5 Intermittent control of emission and/or distribution

One controller can control different rooms/zones having

same occupancy patterns

Electrical power for the pump is drawn only as required –

e.g. during occupancy periods or in protection mode (frost

hazard).

Operating at a lower speed reduces power consumption of

multi-speed pumps.

8 a) With constant Δp: Pressure differential does not

increase at decreasing load when maintaining a

constant pressure differential across the pump. The

pump speed is reduced under part load conditions,

which lowers power consumption.

b) With proportional Δp: Pressure differential across the

pump drops as the load decreases. This provides

additional reductions in speed and electrical power

under part load conditions.

0 No automatic control No savings, since emission and/or distribution are

permanently in operation.

1 Automatic control with fixed time program

To reduce the indoor temperature and the operation time

2 Automatic control with optimum start/stop

To reduce the indoor temperature and the operation time

3 Automatic control with demand evaluation

To reduce the indoor temperature and the operation time

Savings in emission and/or distribution outside the

nominal operating hours.

Additional savings in emission and/or distribution by

continuously optimizing the plant operating hours to the

occupancy times.

The operating time and/or the temperature setpoint for

emission and/or distribution is determined based on consumer

demand. This can be accomplished via the operating

mode (Comfort, PreComfort, Economy, Protection).

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