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Limitation of power consumption

Overview​

info

This feature is not supported by all heat pump series. Specifically, it is unavailable for Liquid/Water heat pumps and cascade systems.

This interface enables the implementation of power limitations in accordance with §14a of the German Energy Industry Act (EnWG). It allows dynamic capping of the heat pump's electrical power consumption.

Behavior during Limitation:​

  1. E-Heater: Will be reduced first, in product-specific possible steps.
  2. Compressor: If the limit is not yet reached after reducing the E-Heater, the compressor speed will be adjusted to meet the target.

Failsafe Behavior:​

In contrast to EEBUS integration, there is no dedicated failsafe for communication interruptions with this interface. The heat pump will automatically return to unlimited normal operation after 4 minutes without receiving any limitation values.

Configuration and Interface Claiming​

To prevent unintended behavior and interference from multiple clients, this Power Limitation API is designed as an exclusive interface. Before power limits can be set, the client must claim the right to use this interface.

Claiming Procedure:​

Send a POST request to the end point /system/powerLimitation with the following request body:

{
  "value": "setpoint"
}

In case an EEBUS device is already paired for power limitation or another client already claimed the power limitation interface, the request will be rejected with HTTP error code 409 (Conflict). In this case, the claim of the other client must be revoked or the EEBUS pairing must be disabled first. This shall ensure, that a §14a-compliant system is not accidentally disconnected.

Client identification is tied to the client token. If a new token is used, the claiming process must be repeated.

Revoking the Claim:​

To release the interface and indicate that a §14a-compliant system is no longer implemented via this API, send a DELETE request to the end point /system/powerLimitation/setpoint without any request body.

Further configuration of the power limitation functionality is not required.

Implementation Guidelines​

Observe the following points for correct integration:

  1. Check Claiming Status: If you receive an HTTP error code 403 (Forbidden) status code after claiming, the claiming was unsuccessful or was overridden by another client. In this case, you can try to repeat the claiming process.
  2. Cyclic Transmission: Limitation values must be sent cyclically. A cycle time of 2-3 minutes is recommended. This ensures that the heat pump does not remain unlimited in case of communication interruptions (see failsafe behavior, 4-minute timeout).
  3. Discrete Power Steps: The heat pump operates with discrete power steps. The backup heater usually has steps of 3 kW, while the compressor offers very fine steps (depending on operating conditions). The interface will select the next possible lower operating point below the set limit. If the limit falls below the compressor's lower modulation limit, the compressor will shut down.
  4. Unlimited State: A limit value of 65535 represents the unlimited state and can also be used in PUT requests to disable the limitation.
note

This interface is designed and intended exclusively for §14a-compliant system implementations and must not be used for other purposes. Use for other purposes overrides and ignores all comfort constraints defined by the end user and is classified as misuse.

Resources​

FunctionUnitreadwritedeleteHMI menu / Resources
Set claim on power limitation functions--x-Not in HMI
/system/powerLimitation
Power limitation of electric power consumption in extended EM role
(Also used as heartbeat for limit control)		Wxx-Not in HMI
/system/powerLimitation/setpoint
Revoke claim on power limitation functions---xNot in HMI
/system/powerLimitation/setpoint

Alternative interfaces​

SG-readyThe heat pumps support the SG-ready standard parallel. With a configurable digital input (on/off), an ESC (EVU) block signal in case of network load optimization. In the summer of 2025, "dimmen" will be an alternative option to "Heat pump blocking."
EEBUSAlternatively, the heat pumps with the Bosch Connect-Key K40RF and Buderus MX400 gateways support the EEBus standard and the EEBus use cases: Limitation of Power Consumption (LPC) and Monitoring of Power Consumption (MPC) in case of the network load optimization.