Design and architectural conclusions
Polish design guidelines require the calculation of the demand for domestic hot water. 150 dm3/day/person, at 55°C. Western standards speak of equal demand 60 dm3/day/person, with a minimum temperature of 45°C.
Performing approximate calculations of the daily demand for hot water based on the Western standard, we get
4,4 x 60 dm³ = 264 dm³/d
Where:
4,4 = average statistical number of people in 1 household in dispersed housing conditions (rural and suburban).
The daily demand for heat will be
Q = 10,8 kWh/d
The capacity of the heat accumulator is determined taking into account e.g. daily water demand, surface area of collectors and method of emergency reheating. Typically, the capacity of the reservoir will be taken equal to 2- to the 3-day water demand or depending on 75 dm* of water per lm2 of collector surface, tj. 530 do 675 dm3 (For 8 do 9 m2 of collectors).
It is justified in theoretical studies, that increasing the surface area of the collectors above the calculated optimum has little effect on the degree of coverage of the demand for heat transferred by solar energy. Doubling of collector surface area z 8 do 16 m2 increases the supply of solar energy by only 5%.
As can be seen from the analyzes of many projects made for climatic conditions similar to those in Poland, surface area of collectors for hot water preparation. ranges from 6 do 14 m2 in single-family housing.
When designing hot water installations,. heated by solar energy, after determining the type of installation, additional source of heat and scheme of operation of the installation, the plumbing engineer and the architect have the following two specific problems to solve, essential to the architecture of the house:
— gdzie i jak rozlokować kolektory słoneczne,
— gdzie umieścić zasobnik ciepła występujący w większości schematów instalacji.
Considering the problem of collectors, whose area and angle of inclination are already known, we consider such a location, which will allow the collectors to be directed as precisely as possible towards the south, that in the hours from 8 up to 16°° they were not shaded. The southern orientation is optimal, but a slight deviation from the south direction is acceptable; np. for Canada, a 15° deviation gives a reduction of 3% absorbed energy, and 30° deflection reduces it by 10%. The inclination of the collectors in relation to the horizontal depends on the period, in which they are to obtain the maximum amount of energy. Solar systems for hot water preparation. can be designed and installed:
— w istniejących obiektach,
— w nowych obiektach, that will not use solar energy in any other way,
— jako integralna część systemu czynnego wykorzystania energii słonecznej do celów grzewczych i przygotowania c.w.u.