The heating circuit calculates the times for the beginning of pre-heat and cool-down optimization in advance. Because the time for optimized pre-heat varies from system to system even with the same temperature conditions, the heating circuit maintains a "model" of the building. The dead time and time constants for the building determine the dynamic behaviour of the model. Due to a strong non-linear behaviour, the heating circuit maintains two building models for pre-heating because it is necessary to distinguish between building characteristics after a short cool-down and after a long cool-down.
Fig. 23. Building model
The building dead times and time constants can be identified by monitoring the start-up progress and comparing the predicted room temperatures with the actually measured ones. The building module parameters will be corrected automatically during the pre-heating time. While enabled, the room model time constants are continuously improved at the end of every optimize start phase. After the dead time the building model constants will be estimated every 15 minutes. The identification is finished after the room temperature control starts. Before the new parameter set is validated, a plausibility check will be performed. .
Depending of the length of the un-occupancy time, the controller will adapt the respective parameter set.
The adaptation of the building model parameters can be done only if:
The adaptation is automatically disabled if one or more of the following conditions are true:
Table 24. Parameter List
Description |
Value Range |
Default Value |
Unit |
BMOD-01: dead time short (adaptive) |
1…60 |
5 |
min |
BMOD-02: time constant short (adaptive) |
30…1440 |
300 |
min |
BMOD-03: dead time long (adaptive) |
1…60 |
5 |
min |
BMOD-04: time constant long (adaptive) |
30…1440 |
600 |
min |
BMOD-05; building model adaptation enable 0 = disable 1 = enable 2 = new start |
0..2 |
1 |
- |