Basic Documentation

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Siemens Universal controllers RMU710B, RMU720B, RMU730B CE1P3150en
Building Technologies Aggregates 03.10.2011
10.4.4 Monitor efficiency of heat recovery system
To activate this function, the relevant two inputs must be assigned.
Main menu > Commissioning > Extra configuration > Aggregates >
Heat recovery equipment >
Operating line Adjustable values / remarks
Efficiency measurement input 1 ---, N.X1, N.X2, ... , Room temperature,
Extract air temperature (only °C, 000.0,
0000)
Efficiency measurement input 2 ---, N.X1, N.X2, ... (only °C, 000.0, 0000)
Efficiency measurement input 1: Extract air or room temperature sensor
Efficiency measurement input 2: Extra sensor
The room temperature must be available in addition (see section 8.4 "Outside
temperature"
).
Operating principle
The efficiency of heat recovery is determined based on three measured
temperature variables. The calculated value is displayed at the operator unit. If the
efficiency is below the settable fault status message threshold (efficiency limit
value), a "Non-urgent message" is generated.
No. Text Effect
3111 HR efficiency
deviation
Non-urgent message, without plant stop; must
be acknowledged and reset
Efficiency may be reduced by faulty, fouled or incorrectly connected heat recovery
equipment.
The efficiency measured serves as an indicator and is not for determining the
absolute performance. It only provides an indication of the magnitude and of the
changes over the operating hours of the heat recovery equipment. The amount of
air delivered has a considerable impact on the efficiency measured. In the case of
speed-controlled fans, this measurement becomes fairly inaccurate since the
amounts of air effectively delivered cannot be determined.
Display of efficiency
During the periods of time where no valid efficiency is available (e.g. one of the
conditions is not satisfied, or there is no stable efficiency, as the system is not in a
stable state, etc.), the display shows "----".
If the efficiency cannot be calculated, no fault status messages are generated.
Select measuring arrangement
You can select between two different measuring arrangements for the sensors:
Main menu > Commissioning > Settings > .... or
Main menu > Settings > Aggregates > Heat recovery equipment >
Operating line Range Factory setting
Measurement
arrangement
Supply air, Exhaust air Exhaust air
Configuration
Explanation
Fault status messages
Note
Setting values