When the maximum value of heat demand at the input “HeatDemandIn” and the minimum supply temperature is less than SST-05, the heat demand transmitted to the heat generators will take the value zero.
If this heat demand exceeds the value SST-05 + 3K, the calculated system supply temperature setpoint is the highest value of the following signals:
This setpoint is increased by parameter SST-03, e.g. 5K, to compensate transmission losses. To prevent the system from heating up too fast the calculated setpoint is always ramped up with the increase rate, as defined by parameter SST-04. This setpoint is limited between the minimum and maximum system supply temperature values, respectively defined by parameters SST-01 and SST-02. The ramping up is shown in the next figure.
The effective heating setpoint is displayed at the output “DispEffHtgSp”.
ATTENTION:
When SST-01 is greater than SST05, there will always be an active heat demand and the strategy will keep the minimum system supply temperature. To save energy take care that SST-01 is alway less than SST-05 whenever possible.
Fig. 2. Heat demand setpoint ramp
Table 1. Parameter List
Description |
Value Range |
Default Value |
Unit |
SST-01: minimum supply temperature |
0...500 |
10 |
°C |
SST-02: maximum supply temperature |
0...500 |
90 |
°C |
SST-03: setpoint raise |
0...50 |
5 |
K |
SST-04: maximum setpoint increment per minute |
1...1000 |
25 |
K |
SST-05: minimum heat demand to start heat generators |
0...150 |
20 |
°C |