Monitoring the energy consumption and usage in the family house

Hardware:	PC, Windows OS
Control stations:	Modbus, MySQL, Communication by OPC DA interface
Date of commission:	2010 - 2022

The system primarily monitors and controls the use of electricity generated by the PV plant. Based on the measured data of the PV plant's actual power output and consumption, the control system operates the SSR relays, which provides a defined power input to the heating elements in the HOT water storage tank. The system thus ensures maximum utilization of the electricity produced by the PV plant, so that the electricity consumption for the house, including the power input of the heating elements from the grid, is zero. The system also monitors the amount of hot water in the DHW storage tank to ensure that there is always enough hot water available. DHW heating at times when there is insufficient sunshine is provided from the distribution network and only at times of low tariff, which is also monitored.



The information about power consumption and production is measured by meters with MODBUS RTU communication or S0 pulse output. The meters are connected to the PLC, which is connected via LAN using OPC Server with SW SCADA PROMOTIC. PROMOTIC provides data visualization from the PLC and also stores these data into the MySQL database. The data from the MySQL DB is then used to display the power and performance profiles. The data is also further used to present consumption, production and profiles of electricity, water and gas on the website. Hot and cold water consumption measurement is provided by water meters with pulse output S0, which is also connected to the PLC. I have had this system including all recorded data in operation since 2010. A few years ago a gas meter was also connected to the system to measure gas consumption. After installing a larger DHW tank and condensing gas boiler, I am preparing to measure flue gas, heating and return water temperatures and DHW temperatures.