Daikin Altherma 3 H MT ECH2O, Installer'S Reference Manual

Page: 219 / 304

10 | Configuration
Installer reference guide
219
EPRA08~W1 + ETSH/X(B)12P30+50EF
Daikin Altherma 3 H MT ECH₂O
4P663478-1 – 2021.07
▪ If Indirect (DHW + SH) is enabled: When boiler operation is more efficient
than heat pump operation (based on energy prices or primary energy efficiency)
the auxiliary boiler primarily provides heat for domestic hot water heating. If the
storage tank temperature is sufficient, the energy provided by the auxiliary boiler
is additionally used for space heating, either supporting the heat pump or
completely covering the building demand.
The switch-over between the heat pump system and the auxiliary boiler is based
on the following settings:
▪ [C‑03] and [C‑04]
▪ Electricity and gas prices ([7.5.1], [7.5.2], [7.5.3], and [7.6]) or PE factor [7-03]
[C‑03], [C‑04], T
calc
, and T
lim
For space heating switch-over: Based on the settings above, the heat pump system
calculates a value T
calc
, which is variable between [C‑03] and [C‑03]+[C‑04].
T
A
T
calc
[C-03]+[C-04]
3°C
[C-03]
a
b
T
A
Outdoor temperature
T
calc
Bivalent ON temperature (variable). Below this temperature, the auxiliary boiler will
always be ON. T
calc
can never go below [C‑03] or above [C‑03]+[C‑04].
3°C Fixed hysteresis to prevent too much switching between heat pump system and
auxiliary boiler
a Auxiliary boiler active
b Auxiliary boiler inactive
If the outdoor
temperature…
Then…
Space heating by the heat
pump system…
Bivalent signal for the
auxiliary boiler is…
Drops below T
calc
Stops Active
Rises above T
calc
+3°C Starts Inactive
# Code Description
9.C.3 [C-03] Range: –25°C~25°C (step: 1°C)
9.C.4 [C-04] Range: 2°C~10°C (step: 1°C)
The higher the value of [C‑04], the higher the
accuracy of the switch-over between the heat
pump system and the auxiliary boiler.
To determine the value of [C‑03], proceed as follows:
1 Determine the COP (= coefficient of performance) using the formula:
Formula Example
COP = (Electricity price / gas price)
(a)
×
boiler efficiency
If:
▪ Electricity price: 20 c€/kWh
▪ Gas price: 6 c€/kWh
▪ Boiler efficiency: 0.9
Then: COP=(20/6)×0.9= 3
(a)
Make sure to use the same units of measurement for the electricity price and gas price
(example: both c€/kWh).