Leppäkosken Sähkö – a year of solar energy and energy savings
Issue 02-2019:
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Thanks to the use of solar energy, the replacement of heat exchangers and intelligent heating control using Micropelt actuators, the total energy consumption of the office building of the energy company Leppäkosken Sähkö in Finland has been reduced by almost 30 percent.
Multiple solar collectors and solar thermal panels were deployed on the office building in Ikaalinen in autumn 2017. The exceptional cold at the beginning of the year and the warm and sunny summer created the ideal conditions for the versatile testing and control of the solar and smart thermostat system.
The Leppäkosken Sähkö Group is a versatile energy company supplying electricity, district heating, natural gas, steam, compressed air and treated water.
Solar-heated district heating in abundance
From the end of April to the end of August, most of the office building’s heating and hot water was produced by solar thermal energy. The total amount of useful heat produced – about 23 MWh –corresponds to just over 8 percent of the annual heat demand of the office building. Only part of the solar thermal heat was utilized for the property’s own needs. In the spring and summer, all surplus solar heat was fed into the Ikaalinen district heating network.
The 5.7 kW electrical solar panel system integrated into the property’s electricity network and its 7.2 kWh electrical storage (battery) enable a technically efficient and flexible utilization of photovoltaic and spot electricity: Solar energy is utilized or the battery is discharged when spot electricity is expensive. The electrical storage is charged when the mains electricity price is cheap or with the solar power produced.
The final result of the Leppäkosken photovoltaic project was the development of a modern, versatile and fully automated photovoltaic and battery system that responds to the market price of electricity.
Energy consumption of the Leppäkosken office building in 2018 compared to 2017. MWh according to the scale on the left, average temperatures in °C marked with lines according to the scale on the right.
New heat exchangers for more energy efficiency
As part of improving the energy efficiency of the property, the 20-year-old heat exchangers were also renewed. At the beginning of the year, the company also replaced all the manual radiator thermostats (around 50 units) of the water heating system in the office building with Micropelt’s MVA004 remote-controlled smart thermostats. Based on the experiences from winter, spring, summer and early autumn, the smart thermostat surpassed all expectations in terms of reliability and controllability. Room and room-temperature control accuracy were excellent.
Temperature difference generates electrical energy
These self-powered actuators offer several advantages. Thanks to the built-in thermoelectric generator (TEG) for power generation, this actuator requires neither cables nor batteries. The intelligent MVA004 thermostat generates its electrical energy from the temperature difference between hot water and circulating room air.
Communication between the radiator actuator and room controller/controller or a Building Management Software (BMS) is via EnOcean’s standardized radio protocol. The intelligent thermostat is suitable for most water circulation heating systems and for large buildings in particular.
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