Electronic systems for renewable energy sources, home automation

Example of energy savings

In the charts below there is possible to see the amount of self-consumed energy before and after WATTrouter CWx has been installed (WATTrouter M series use the same control mechanisms thus the result would be the same).

The controller was installed on 24th July 2010 in a house with just 2,0 kWp photovoltaic plant. In this house there live 2 people. There was only hot water boiler connected to WATTrouter's built-in triac output in 1st priority. CombiWATT was activated for this boiler. Normally the boiler run at night in this house because the electricity was cheaper (low energy price tariff). Further there was connected a dryer for wet rooms in the house on relay 1, 2nd priority. The consumption from grid at night (low tariff) decreased immediately. There was still some surplus energy which could not be used and thus let flow to public grid. Important is that daily power consumption in normal tariff did not increase.

The energy flows through main electricity meter decreased substantially in both directions. Money savings per year were equal to 70 EUR. It is obvious that money savings increase proportional to the PV-plant peak power, as well as proportional to the ability to consume the surplus energy.

In both charts HT stands for regular (higher price) electricity tariff and LT for low (lower price) electricity tariff.

Notes to following chart: In november 2010 there was electric heating connected to WATTrouter and CombiWATT was activated for this heating. In April 2011 this heating has been disabled. This heating explains higher consumption from power grid in these months.