Sizing The Plate Heat Exchanger; Connection Of Solar Thermal Systems - Viessmann VITOCAL 300-G Technical Manual

Design information
For more detailed information regarding systems with swimming pool
water heating, see "Heat pump system examples".

Sizing the plate heat exchanger

28 °C 38 °C
22 °C 28 °C
External swimming pool for average water temperatures up to 24 °C.
A Swimming pool (swimming pool water)
B Heat pump (heating water)
Selection list, plate heat exchangers for swimming pools
Heat pump type
Single stage heat pump
BW 121
WW 121
BW 129
WW 129
BW 145
WW 145
Two-stage heat pump, both stages with the same output
BW+BWS 121+121
WW+BWS 121+121
BW+BWS 129+129
WW+BWS 129+129
BW+BWS 145+145
WW+BWS 145+145
Two-stage heat pump, stages with different output
BW+BWS 121+129
WW+BWS 121+129
BW+BWS 121+145
WW+BWS 121+145
BW+BWS 129+145
WW+BWS 129+145

3.14 Connection of solar thermal systems

The installation of a Vitosolic solar control unit enables a solar thermal
system to be controlled to provide DHW heating, central heating
backup and swimming pool water heating. The heat-up priority can be
selected individually at the heat pump control unit.
Via the KM BUS certain values can be checked at the heat pump con-
trol unit.
When there is a high level of insolation, all heat consumers can be
heated to a higher set value, thereby raising the solar coverage. All
solar temperatures and set values can be scanned and adjusted via
the control unit.
The operation of the solar thermal system will be suspended at col-
lector temperatures > 120 °C to prevent steam hammer inside the solar
circuit (collector protection function).
Solar DHW heating
The solar circuit pump starts and the DHW cylinder is heated up, if the
temperature differential between the collector temperature sensor and
the cylinder temperature sensor (in the solar return) is greater than the
start temperature differential set at the solar control unit.
VITOCAL 300-G
(cont.)
Output in kW
Flow rate in m
(for B15/W35) Swimming pool
31
41.2
63.6
62
82.4
127.2
72.2
94.6
104.8
Use only stainless steel heat exchangers (threaded) that are suitable
for potable water for heating swimming pool water.
Size the plate heat exchanger subject to the max. output and the tem-
perature specified for the plate heat exchanger.
Note
The flow rate calculated during sizing must be maintained during the
installation.
3
/h
Heat pump (heating water)
4.4
5.9
9.1
8.9
11.8
18.2
10.3
13.6
15.0
The heat pump will be prevented from heating the cylinder if the tem-
perature at the cylinder temperature sensor (in the DHW cylinder, top)
exceeds the set value selected at the heat pump control unit.
The solar thermal system heats the cylinder to the set value selected
at the solar control unit.
Note
For the aperture area that can be connected, see the "Vitosol" techni-
cal guide.
Solar central heating backup
The solar circuit pump and the circulation pump for cylinder heating
start, meaning the heating water buffer cylinder is heated up, if the
temperature differential between the collector temperature sensor and
the cylinder temperature sensor (solar) is greater than the start tem-
perature differential selected at the heat pump control unit.
3
2.7
3.5
5.5
5.3
7.1
10.9
6.2
8.1
9.0
VIESMANN
57