Environmental Engineering Reference
In-Depth Information
The energy gained by the incident solar radiation absorbed by the pool depends
on the pool surface area and the degree of absorption of the pool water and the
pool floor. The degree of absorption increases as the colour of the pool bottom
and walls darken from white over light blue to dark blue, as well as with increas-
ing water depth. Additional energy can be generated depending on the heat re-
leased by the swimmers; depending on the swimmer's movements, the heat capac-
ity is between 100 and 400 W per swimmer /4-2/.
Collector area
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Boiler
Fig. 4.12
Layout and energy flows of a solar open-air swimming pool heating system (see
/4-1/)
Any energy demand that goes beyond this energy generation has to be pro-
duced by the absorbers or another fossil fuel (e.g. natural gas) or renewable en-
ergy carrier (e.g. wooden pellets) driven heater. Considering a swimming period
of 130 days, between 540 and 1,620 MJ are required per square metre of pool
area. The absorber area should be between 50 and 70 % of the pool area in order
to achieve a mean temperature increase between 3 and 6 °C, depending on the
pool cover (e.g. /4-2, /4-3/).
Small systems.
In the past, the use of solar thermal systems in domestic house-
holds was limited mainly to solar-supported domestic hot water (DHW) heating.
The additional space heating support by a solar system, also called solar combined
system, is becoming increasingly significant. In Austria and Switzerland, 50 % off
all solar systems can be categorised as combined systems /4-12/, /4-13/.
For such systems it is important to consider that the energy demand for domes-
tic hot water is normally at the same level throughout the year; the demand for
space heating, however, is generally inversely related with the solar radiation
available.
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