Environmental Engineering Reference
In-Depth Information
−
Solar system (e.g. collector area and efficiency);
−
User requirements (constant room temperature or possible temperature fluctua-
tions of several degrees);
−
User goal (highest possible efficiency with large effort or good efficiency at
low costs) /4-6/.
As examples, Fig. 4.15 shows three types of system design. The left side of the
graphic shows a two-storage layout with a power-controlled automatic boiler. One
store is used to produce domestic hot water and the second to partly cover the
demand for space heating with solar energy. In this case, the water heated in the
boiler is directly fed into the space heating network (Fig. 4.15, left). If it is not a
power-controlled boiler (e.g. wood pellets) it would have to be integrated via the
space heating storage in order to achieve an increased running time and a mass
flow decoupled from the mass flow of the space heating system. External heat
exchangers are often used to charge the space heating store due to the larger col-
lector areas for solar combined systems.
Two stores with
oil or gas-fired boiler
Tank in tank storage with
solid fuel boiler
Single storage with inegrated
gas-condensing boiler
Collector
Collector
Collector
Space
heating
storage
Combistore
Solar-
controller
Solar-
controller
Domestic
hot
water
Dom.
hot
water
Solar-
controller
Domestic
hot
water
Gas-
condensing
boier
Dom. hot
water
storage
Cold
water
Cold
water
Dom. hot
water
storage
Cold
water
Main storage
(tank-in-tank)
Stratifying units
External
heat exchanger
Boiler
Fig. 4.15
Possible types of solar thermal systems to cover domestic hot water and space
heating demands (solar combined systems) (Dom. domestic; see /4-6/, /4-13/)
The system in the middle and the system on the right in Fig. 4.15 are variations
of single-storage systems. In terms of installation, they are easier to handle than
storage devices that are installed separately. The double heat transfer, however, is
a disadvantage (collector/storage and storage/domestic hot water heater).
The system in the middle in Fig. 4.15 is particularly suitable for solar systems
in combination with a comparable inert solid fuel boiler (e.g. wood heating
boiler). The domestic hot water pressurised tank is integrated into a larger heating
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