BA_OTE 3+4_Endkunde_EN_V03_20170726.docx
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17
Heat meter
The OTE control offers the possibility of recording the amount of heat the heat pump
gives off. The recording takes place using the classic heat meter method. The temperature
differential of the heat pump is continuously measured and the amount of heat calculated
with the flow rate.
Prerequisite for reproducible heat amounts is the calibration of the EC-pumps, the hy-
draulic balance in the system as well as the correct installation of the flow sensors.
This is to be carried out by the system partner/system installer in the course of commis-
sioning.
The
annual performance factor (APF)
for electrically driven heat pumps is the result of
the division of the amount of heat given off (displayed on the OTE) by the amount of elec-
tricity used (readable from the heat pump tariff meter)
APF =
)
(
)
(
e
Heizperiod
el
e
Heizperiod
th
W
Q
The end customer is to be informed by the system installer that for the calculation of the
APF to VDI 4650, normative values (comp. norm fuel consumption in cars) will be used.
Using these normative values, today's comfort demands will not be met!
The
measured APF
is essentially dependent on user behaviour and other factors and is
less than the
COP1
and the
APF as calculated to VDI 4650
1
COP =
C
oefficient
o
f
P
erformance: Heat pump's Performance factor, instantaneous value, COP ≠ APF
2
VDI 4650: Policy which defines the calculation procedure for annual performance factors
