DAB Advanced Terminal Logic & Tuners

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[DAB Core Logic]
[DAB Damper Position]

Now that you understand how the damper position at the zone level is calculated it's time to understand a few additional concepts that can affect the actual output position of the damper.

| Normalization

In a DAB system, it is assumed that the system is constant volume and that when you are heating or cooling there is at least one zone with the largest load. The load in that space may be a 65% loop output or something which wouldn't calculate a 100% damper position by itself. Normalization is implemented here where all zones will add to their calculated damper position so that at least 1 damper is at 100% 

65% Loop output would give you roughly an 80% damper position. So if this was the highest calculated damper position but the other 4 zones on that system had damper positions of 55,65,70, and 75%.

Normalization Calculation Example:

Considering the 75% as the highest of the Damper position 

Normalization % = (100- Maximum Damper Position)*(100/ Maximum Damper Position)

 = (100-75)*(100/75)

=25*1.33

=33.33%

What would happen is you would add 33% of the actual Damper position to all damper positions to normalize them as follows:

• Normalized Damper position, for an actual Damper position 55% =((33.33*55)/100)+55=73.33%
• Normalized Damper position, for an actual Damper position 65% = ((33.33*65)/100)+65= 86.66%
• Normalized Damper position, for an actual Damper position 70% = ((33.33*70)/100)+70= 93.33%
• Normalized Damper position, for an actual Damper position 75% = ((33.33*75)/100)+70= 99.99%

| Minimum Overall Damper Position

This is another concept that will scale up the damper positions. Since DAB is installed on CAV systems and there is no implied pressure relief, we came up with a way to keep the average damper opening from being lower than is typically safe. This tuner is called targetCumulativeDamperOpening. 

weightedDamperOpening = (Zone1_damperPosition*Zone1_damperSize + Zone1_damperPosition*Zone1_damperSize+etc..)/(Zone1_damperSize+Zone2_damperSize+etc..)

If weightedDamperOpening < targetCumulativeDamperOpening then add 1% to all damper position until weightedDamperOpening > targetCumulativeDamperOpening

| Zone Priority

Zone priority is not used by the zone for zone-level calculations but is calculated per zone. This concept will be more important when we dive into the AHU control logic of DAB. 

Zone Priority (zoneBasePriority) has 4 levels each with a numeric value. Zone priority is a value set by the user to give a relative ranking of importance for each zone. 

• No Priority = 0
• Low Priority = 1
• Medium Priority = 10
• High Priority = 50

Zone Priority is the user setting, and zoneDynamicPriority is the actual zone priority used by the system and is important to understand. Here is the calculation for zoneDynamicPriority. 

zoneDynamicPriority = zoneBasePriority*((zonePriorityMultiplier)^(tempError/zonePrioritySpread))

Tuners

zonePrioritySpread = default 2

zonPriorityMultiplier = default 1.3

Zone Priority Example: Zone 1 temp is 76, and the desired temp is 70 with a default priority of medium. 
zoneDynamicPriority= 10*(1.3^((76-70)/2)) = 21.97

| DAB Terminal Tuners

Tuners are the features of the Airoverse system, which are a set of predefined parameters that can be modified or changed to customize and finely tune our system's functioning to cater to specific building types and specific customer needs.

Below are tuners applicable for DAB Terminal Profiles: