83/106
Siemens
Basic Documentation RVP360
CE1P2546en
Building Technologies
18 Function block: Solar d.h.w.
2017-07-24
18.3 Functions
18.3.1 Temperature differential ON/OFF solar
Operating lines 201 and 202 are used to set the temperature differential for switch-
ing solar d.h.w. charging on and off.
A certain temperature differential of collector and storage tank is required for charg-
ing; also, the collector must have reached the minimum charging temperature.
ON
OFF
SD
OFF
SD
ON
TLmin
TKol
Collector temperature
TSp
Storage tank temperature
ON/OFF Collector pump
TLmin Minimum charging temperature
SD
ON
Temperature differential ON
T
Temperature
SD
OFF
Temperature differential OFF
t
Time
The storage tank is charged when the collector temperature exceeds the current
storage tank temperature by the switch-on differential:
TKol > TSp + SD
ON
Storage tank charging is stopped when the collector temperature drops below
the switch-off differential:
TKol < TSp + SD
OFF
18.3.2 Minimum charging temperature
The collector pump is only activated when the collector reaches a minimum tem-
perature of 30 °C and when the required temperature differential is attained.
ON
OFF
TLmin 30 °C
TKol
Collector temperature
TLmin
Minimum charging temperature
ON/OFF Collector pump
T
Temperature
SD
ON
Temperature differential ON
t
Time
SD
OFF
Temperature differential OFF
Charging is aborted when the collector temperature drops below the minimum
charging temperature (even if the switch-on differential is reached):
TKol < TLmin
Charging is effected when the collector temperature exceeds the minimum charg-
ing temperature by the switching differential (SD
ON
– SD
OFF
) (and when the re-
quired switch-on differential is reached):
TKol > TLmin + (SD
ON
– SD
OFF
)