User Manual

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11.3 ERC control behavior
The best known, conventional control procedures for ERC are list below.
– Stg 1: Strategy Max ERC recovery ERC is fully controlled
– Stg 2: Strategy Temp. ERC is integrated in the temperature
sequence
– Stg 3: Strategy Hum. ERC is integrated in the humidity sequence
– Stg 4: Strategy Enthalpy. ERC is controlled to the supply air setpoint
enthalpy.
The air state after ERC depends on the selected strategy.
Figure 11-2
h,x diagram with schematic of the 4 strategies.
On the ERC lines, i.e. in the case of recirculated air on the line between the outside air and extract air,
all possible states for the mixed air are entered after mixed air damper control.
4 points on the line are special; they are the starting points for energy calculations.
Ex Extract air SpSu Supply air setpoint
x Steam content absolute T Temperature
Oa Outside air
Energy consumption is calculated based on air states 1 and 2 as per Figure 11-3
and the weighting factors to evaluate the energy of the strategies per strategy:
– State 2 is given by the supply air temperature and supply air humidity.
– State 1 can be determined for temperature and humidity based on the ERC
strategy and the effectiveness of the ERC.
– Calculation of energy costs considers the related air handling aggregates and
their specific costs. Involved aggregates result from the required change of state
and aggregate-specific, possible changes of state.
The strategies Stg 1 to Stg 4 (Figure 11-2) are displayed in DESIGO INSIGHT. For
inactive strategies, the setpoint for Sta 2 is used for calculation, see Table 3-7.