The excess of energy generation

SymBox – Your Excess Energy Optimizer


Our product “SymBox” is capable of connecting various smart home systems like KNX, LCN, EnOcean, Z-Wave, ModBus, WallBoxes, BACnet (and a lot more) which builds the foundation of one smart home solution that is able to control all devices in the home/building. For this project we want to present our “excess energy optimizer” combined with our “energy distribution” view that gives insight about energy consumption and available excess energy. The available excess energy will then be used in the best way possible or according to priorities that the owner/administrator has given. At any given moment, the owner/administrator can override the decision of the intelligent optimizer with simple controls in the visualization. The controls allow for the automatic mode and manually disabling the consumer or enabling the consumer to a chosen value.

The “excess energy optimizer” supports the following devices types: switchable, dimmable and EVs. Switchable and dimmable devices are probably straight forward in the usage – enable devices if enough excess energy is available. But, to be most effective, the optimizer prioritizes switchable devices first and then fills up the left excess energy with dimmable devices, which can be controlled with more granularity. EVs on the other hand need special care – at first, most EVs need at least 6A before charging can start. Then, if the wallbox supports it, we need to take care to switch from 1 phased charging to 3 phased charging. One interesting fact: Between 1 phased charging and 3 phased charging there is a gap in usage of 460W. Of cause we redirect this energy to another consumer and disable the consumer if we can switch to 3 phased charging. The math: (3*6A*230V) = 4140W; (1*16A*230V) = 3680W; 4140W – 3680W = 460W.

Another feature of the optimizer is support for additional conditions, that can be specified by the owner/administrator. Examples are maximum target temperatures, weekday/date/time restrictions or SoC targets (like max. 80%) for EVs. Unfulfilled conditions are shown in the visualization to clearly show why this consumer is not participating in the optimization at any given moment.

For our demo setup we partnered with Lingg&Janke – a long time KNX Member and renowned KNX manufacturer – which provided us with their KNX Secure eHZ interface to receive real time excess energy data from our meters and with their KNX Secure two channel high-load dimmer to be able to optimally use the excess energy with two heating elements. On the EV side we used an Alfen Wallbox that was connected through ModBus TCP. (This may have been any other manufacturer as well, that supports controlling the charging like ABL, Mennekes, KEBA, go e-charge, …). Everything is connected to our SymBox, which also has an integrated, certified KNX TP interface from Weinzierl. (At the moment we are in the process of certifying our SymBox also for KNX Data Secure)

Of cause any KNX device and non KNX device that is compatible with the SymBox can be added to the “excess energy optimizer” and even multiple EVs can be connected effortlessly. As a side note: We also support 2 phased charging, which is common for BMW motorcycles.

A demo of this project can be tested online:

List of screenshots:
1) View of the web visualization (also available as an app for iOS/Android)
2) View of the energy excess optimizer configuration
3) Used devices in our lab-experiment (The Alfen Wallbox is connected via network outside of the building)

Team name
Michael Maroszek
Team leader
Klaus Ott
Team member