EnergyLevelSetpoint (FB)¶

FUNCTION_BLOCK EnergyLevelSetpoint

Selects the energy level releated setpoint of a building (part) or system part (like a HVAC plant powering a building).

The purpose of selecting an energy level is to optimize energy consumption.

EnergyLevelSetpoint differentiates between four levels with increasing energy demands:

“protection”
“economy”
“pre-comfort”
“comfort”

The “protection” energy level is using the minimum energy amount to prevent damage to the building fabric and the building technical installation. The building / system part is controlled using this level if temporarily out of use.

The “economy” energy level is an energy saving mode of a building or system part which is not occupied or not being used for longer periods (at night, weekend etc.). The “pre-comfort” energy level is an energy saving mode of a building or system part which is supposed to reach “comfort” level within a short period. The “comfort” energy level is the state intended for nomal usage of an occupied building.

VDI 3814 reference¶

EnergyLevelSetpoint is oriented towards VDI 3814 3.1 “Optimisation functions” “Energy Mode” (6.3.6.1), but is different in some aspects.

VDI 3814 “Energy Mode” (6.3.6.1) implies some aspects which at least give room for discussions:

room occupation state and window contact

Operation mode computation in room controllers is more complex than those two aspects. So EnergyLevelSetpoint doesnt provide those isolated aspects and leaves them up to a more complex room controller function block. Because of this there is no need for an output “current operation mode”.
hysteresis for building protection limit

The “no energy zone” between heat setpoint and cool setpoint is sufficient to ensure building protection and avoiding unneccesary energy consumption. Requesting a hysteresis does imply kind of two-position control - which is neither needed to request nor fully specified in VDI 3814 “Energy Mode”. So EnergyLevelSetpoint doesnt provide this and leaves this aspect up to a more complex room controller function block.
current setpoint

Providing just one current setpoint does imply single sequence control driven by this setpoint. Control algorithm tend to be more complex than this, multi-sequence-control is quiet often the default. So EnergyLevelSetpoint provides the current heat setpoint and cool setpoint.

InOut:

Scope	Name	Type	Initial	Comment
Input	`eLevel`	EnergyLevel		Energy level
	`rSetptHeatComfort`	`REAL`	21.0	Heat setpoint comfort level
	`rSetptCoolComfort`	`REAL`	23.0	Cool setpoint comfort level
	`rSetptHeatPreComfort`	`REAL`	19.0	Heat setpoint pre-comfort level
	`rSetptCoolPreComfort`	`REAL`	25.0	Cool setpoint pre-comfort level
	`rSetptHeatEconomy`	`REAL`	16.0	Heat setpoint economy level
	`rSetptCoolEconomy`	`REAL`	28.0	Cool setpoint economy level
	`rSetptHeatProtection`	`REAL`	10.0	Heat setpoint protection level
	`rSetptCoolProtection`	`REAL`	40.0	Cool setpoint protection level
Output	`rSetptHeat`	`REAL`		Current heat setpoint
Output	`rSetptCool`	`REAL`		Current cool setpoint