Solar electricity for self-consumption in the guest house "Green Island"

Solar electricity for self-consumption in the guest house "Green Island"

By implementing the planned improvements of the heating and electricity generation systems in the guest house "Zaļā sala", the energy efficiency of the buildings was significantly increased and the stability of the functioning equipment was ensured. The project is interesting in that it installed both a solar panel and a solar collector system at the same time.

Object type: Guest house
Location: Near Rezekne

Solar battery application: Electricity for own consumption, Microgenerator connection

Solar battery area: 23.5 m2
Number of solar batteries: 14 pcs.
Total power: 3.92kW
Type of photovoltaic panels: Monocrystalline glass / glass
Battery type: Saltwater batteries (with 100% discharge)
Battery capacity: 9kWh

Application of solar collectors: Water heating and heating support

Number of solar collectors: 6 pcs.
Solar collector area: 15.2 m2
Solar unit power: 10.9 kW

The system has been operating since 2017.

Solar battery system

Prior to the installation of the new solar system, the guest house consumed an average of 2,200kWh of electricity each month. As far as the company's operations and costs are formed mostly on four days of the week - Thursday, Friday, Saturday, Sunday, then it can be calculated that on average about 120-140kWh of electricity is consumed on these load days. Part of the electricity was consumed for heating water during the summer with electric water boilers, which is about 40kWh per day. The rest of the electricity consumption consisted mainly of kitchen costs, in which a convection oven 10 kW, a stove 14 kW, refrigerators 4 kW, etc. were operated. Equipment.

The currently installed solar system is able to produce as much as 30-40 kWh of electricity on a sunny summer day, which is partly diverted to direct consumption, but part is stored in electric batteries so that energy can be used on weekends when peak consumption.

Solar collector system

The hot water usage habits in the guest house are significantly different from the residential building. The company's main water consumption is on weekends, when social events are held. On the other hand, there is relatively little hot water consumption on the other days of the week.

Taking into account the specifics of the operation of this guest house, it was decided to install a relatively low-power solar collector system (10.9 kW), which was supplemented with two storage tanks with a total volume of 4 cubic meters. This ensures that heat energy is efficiently stored on relatively 'empty days' (Monday to Thursday) but used on those days of the week when the guest house is most busy (Thursday to Sunday), as various events are organized.

To ensure the accumulation of water in a bacteria-free environment, an accumulation tank was installed in which drinking water is heated using the so-called "flow principle".

With the help of the currently installed solar collector system, the hot water needs are fully met during the six warmest months of the year. This means that at least 50% of the costs associated with hot water preparation have been reduced. On the other hand, thanks to solar collectors, on average 65-70% of the total amount of hot water is provided free of charge.