Example:
Imagine a residential building with 45 residential units occupied by about 117 people. If the water consumption per person is on average 26,3 l per day, then the annual heat demand for hot water reaches 58 400 kWh per year.
The annual gain from 28 solar panels installed on such a building comes to 32 974 kWh. The annual cost at a price of 1, 54 CZK/kWh (price of gas as at 1. 8. 2011) works out as follows:
1. Without solar panels - 89 936 CZK
2. Using solar panels - 39 156 CZK
3. Annual saving (66 %) - 50 780 CZK
With 45 flats the saving per flat
is 1 129 CZK!
How much can be saved by using energy from the sun?
The amount of solar energy is so huge that even though the Earth intercepts less than 2 milliardths of the solar energy flux, about 1360 W/m2 reaches the boundary of the atmosphere. A part radiates back into the outer space, another part of the radiation is absorbed in the passage through the atmosphere and, in spite of that, about 1000 W/ m2 still falls on the Earth's surface. It is logical (and ecological) to capture this energy and use it as heat or electrical energy, and this is what Skanska co. is doing in the implementation of their environmental projects.
The amount of solar energy is so huge that even though the Earth intercepts less than 2 milliardths of the solar energy flux, about 1360 W/m2 reaches the boundary of the atmosphere. A part radiates back into the outer space, another part of the radiation is absorbed in the passage through the atmosphere and, in spite of that, about 1000 W/ m2 still falls on the Earth's surface. It is logical (and ecological) to capture this energy and use it as heat or electrical energy, and this is what Skanska co. is doing in the implementation of their environmental projects.
