Nowadays, the energy prices are high, and integration of solar energy into water heating system is almost a necessity.
Most households spend up to approx. 700 litres of fuel oil for water heating. The solar collectors can save up to 80% of the energy required for domestic hot water heating.
The system solution most often includes solar panels and a water heater. In practice, the most common variant is an installation of three solar collectors and a 300-litre water heater, which is sufficient for up to 6 people, if used economically.
In the winter, or when the solar energy is scarce, you can use the existing water heater or any other energy source (e.g. electricity or heat pump) as an additional source of heating water.
The advantages of STROJ water heating solar system
- Heat transfer fluid
There is no need to apply any antifreeze. Water is used as the heat transfer fluid in any season.
- System safeguards
The water is present in the solar collectors only when their temperature exceeds the temperature in the lower part of the water heater (buffer tank). In the event of heat loss, the water withdraws into a special combined expansion STROJ tank, increasing efficiency.
- Heat transfer fluid current resistance
The heat transfer fluid is water with low viscosity. To achieve lower resistance, we use water pipes of smaller diameters, which reduce the heat loss and increases water transfer efficiency.
- Overheating above 100 °C
In the event of a power failure, the water automatically withdraws from the solar panels into an expansion tank to avoid evaporation or freezing.
The combined expansion tank is optimised for use in STROJ heating system, and is patent protected. The open type expansion tank is responsible for creating pressure in the heating system, the accumulation of retreating water from the solar and heating system, and acts as a safeguard against overheating. It is located at least 500 mm above the upper level of the highest heater (radiator) and at least 200 mm below the lowest level of solar energy collector (SEC). The pump moves water through SEC and transports it through the combined expansion tank, from where the water returns to the water heater or furnace for central heating.
The operation of the combined expansion tank does not need any additional electricity supply. The water circulates through the system with the help of the system pump. If there is a risk of freezing of the heat transfer fluid (water without antifreeze), the water retreats to its designated space (expansion tank). The water also withdraws from SEC in the event of a negative temperature differences, and in case of extremely weak solar radiation. The tank must be large enough to receive any water flowing thorough SEC, and the pipeline leading to/from SEC.
The water retreats from the solar system whenever the conditions are unfavourable for the contribution of heat (no solar radiation, low temperatures, temperature in SEC is lower than the temperature in the boiler, etc.). Guaranteed positive difference in temperature allows for operation at favourable terms, which indirectly increases the effectiveness of the entire system.