ᐅ Optimization of the LWD 70A Heat Pump with Photovoltaic System

Created on: 3 Sep 2023 16:22
F
Fabian80
Hello everyone,
I’m a layperson and therefore looking for your advice.

I recently installed a 13.9 kWp photovoltaic system and now want to optimize my heat pump settings to work more efficiently with the solar system. It is an LWD 70A Alpha Innotec heat pump.

1) Adjust hot water settings with lockout times, suitable hysteresis and temperature/differential settings, and configure the electric heating element accordingly.
2) Reduce compressor pulses and optimize the heating system accordingly.

I would like to start with point 1, as I think this might be simpler. Do you have any recommendations?

Thank you very much for your help.

Heat Pump Commissioning: 09/03/2023 15:

System Status:
Heat Pump Type LD7
Software Version V2.88.3
Revision 9717
Control Panel 1003
Bivalence Stage 1
Operating Status ----

System Settings:
Utility Lockout without Backup Electric Heater (ZWE)
Room Controller No
Return Integration No
Mixing Circuit 1 No
Mixing Circuit 2 No
Mixing Circuit 3 No
Backup Electric Heater 1 Type: Electric Heating Element
Backup Electric Heater 1 Function: Heating and ...
Backup Electric Heater 1 Power: 6.0 kW
Backup Electric Heater 2 Type: None
Backup Electric Heater 2 Function: None
Backup Electric Heater 3 Type: None
Backup Electric Heater 3 Function: None
Fault without Backup Electric Heater
Domestic Hot Water Sensor 1
Domestic Hot Water Sensor 2 ZIP
Domestic Hot Water Sensor 3 with ZUP
Domestic Hot Water Sensor 4 Setpoint
Domestic Hot Water Sensor 5 with HUP
Domestic Hot Water + Heat Pump max 0.0 h
Pump Optimization Yes
Customer Access
Pressure Monitoring On
Heating Circuit Control Outside Temperature Dependent
Mixing Circuit 1 Control Outside Temperature Dependent
Mixing Circuit 2 Control Outside Temperature Dependent
Mixing Circuit 3 Control Outside Temperature Dependent
Heating with Mixing Circuit No
Electric Anode No
Heating Limit Yes
Parallel Operation No
Remote Maintenance No
Pump Optimization Time 180 min
Pump Efficiency Yes
Heat Quantity Cooling
Solar Control Temperature Differential
TDI Message Yes
Multi-Tank No
Backup Electric Heater Release 60 min
Hot Water Post-Heating No
Hot Water Post-Heating Max 5.0
Smart Grid No
Mixing Circuit 1 Control Fast
Mixing Circuit 2 Control Fast
Mixing Circuit 3 Control Fast

Temperatures:

Return Limitation 50.0°C (122°F)
Hysteresis HR 2.0 K
Max Compressor Boost 7.0
Backup Electric Heater Release -2.0°C (28°F)
Air Temperature Differential 7.0°C (45°F)
TDI Set Temperature 65.0°C (149°F)

Hot Water Hysteresis 2.0 K
Max Outdoor Temperature 40.0°C (104°F)
Min Outdoor Temperature -20.0°C (-4°F)
End Air Temperature Differential 6.0°C (43°F)

Setback down to -20.0°C (-4°F)
Max Flow Temperature 70.0°C (158°F)
Temperature Differential On 4.0 K
Temperature Differential Off 2.0 K
Max Storage Temperature Differential 70.0°C (158°F)
Heating Circuit Temperature Differential 2.0 K
Hot Water Temperature Differential 5.0 K
Min. Outside Temperature Flow Max.
Ground Floor Flow 62.0°C (144°F)
Max Hot Water Temperature 65.0°C (149°F)
Min Return Set Temperature 15.0°C (59°F)
Night Setback Heating Circuit 0.0°C (32°F)
Heating Limit:
Heating Limit 17.0°C (63°F)

Pump Efficiency:
Nominal Pump Efficiency 8.25 V
Minimum Pump Efficiency 8.25 V
Pump Efficiency Yes

Heat Quantity Cooling Priorities:
Domestic Hot Water 1
Heating 2

System Configuration:
Heating 1
Domestic Hot Water 1
Swimming Pool 0
Heating Curve Heating 34.0°C (93°F) 20.0°C (68°F)

Operating Hours Information:
Operating Hours Compressor 1: 5583 h
Compressor Pulses 1: 18619
Average Operating Time Compressor 1: 00:17
Backup Electric Heater 1 Operating Hours: 5 h
Heat Pump Operating Hours: 5583 h
Heating Operating Hours: 4738 h
Domestic Hot Water Operating Hours: 845 h

Temperature Information:
Flow 36.3°C (97°F)
Return 35.2°C (95°F)
Return Setpoint 15.0°C (59°F)
Hot Gas 40.9°C (105°F)
Outdoor Temperature 24.0°C (75°F)
Average Temperature 18.0°C (64°F)
Actual Domestic Hot Water Temperature 48.7°C (119°F)
Target Domestic Hot Water Temperature 48.0°C (118°F)
Heat Source Inlet 26.1°C (79°F)
Solar Collector 5.0°C (41°F)
Solar Storage 150.0°C (302°F)
External Energy Source 5.0°C (41°F)
Max Flow Temperature 70.0°C (158°F)
Compressor Suction 48.9°C (120°F)
Evaporator Suction 34.6°C (94°F)
Compressor Heating 60.5°C (141°F)
Superheating 28.9 K
Target Superheating 8.0 K

Yes = Yes

Shutdowns:
09/03/23 14:05 No Errors
09/03/23 08:21 No Errors
09/03/23 00:50 No Errors
09/02/23 18:35 No Errors
09/02/23 15:33 No Errors

Calibration:
NTC1 0.0
NTC2 0.0
NTC3 0.0
NTC4 0.0
NTC5 0.0
NTC6 0.0
NTC7 0.0
NTC8 0.0
B
Benutzer 1001
4 Sep 2023 04:57
Buchsbaum schrieb:

What do you mean by restricted hours? Heat when the sun is shining.
Of course I want to heat during the winter when the sun is shining. Or did you not understand how a heat pump works?
B
Buchsbaum
4 Sep 2023 07:25
In winter, the output of your photovoltaic system is close to zero—regardless of the type of modules installed or the size of your system. Let’s assume a typical system on a single-family home. The photovoltaic system might provide a few kilowatt-hours, but this can generally be neglected.

The number of sunny days from November to February is limited; we have had Novembers without any sun, plus snow and ice, shorter days, and the sun is lower on the horizon.

Since the highest electricity demand of a heat pump naturally occurs in winter, it requires the most power when photovoltaic generation is at its lowest. Therefore, heating with electricity is necessary.

I am genuinely curious how owners of heat pumps will respond to their high electricity consumption during a truly freezing winter. When outdoor temperatures remain around minus 20 degrees Celsius (minus 4 degrees Fahrenheit) for weeks, and the supply temperature has to be electrically boosted to 36°C (97°F). And whether 36°C (97°F) supply temperature is sufficient, even for well-insulated houses. This will certainly be interesting to see.

In recent years, winters have been mild. And if the argument about Norway comes up again—yes, it is much colder and darker there than here. But it must not be forgotten that a Norwegian pays only 4 cents per kilowatt-hour, whereas here it is around 40 cents.

That’s a factor of 10 more expensive. Heating electrically has never been efficient or cost-effective.
B
Benutzer 1001
4 Sep 2023 10:10
That’s why it’s better to schedule heating cycles during the day, as it is naturally warmer than at night. This usually results in a better coefficient of performance (COP). Also, if there is no snow on the panels, the photovoltaic system might still generate a few kilowatts.

And this is an on/off heat pump; its runtime of 17 minutes shows that it is not operating optimally.
K
KarstenausNRW
4 Sep 2023 10:43
Buchsbaum schrieb:

I’m actually curious to see how heat pump owners will react to the high electricity consumption of their heat pumps during a really freezing winter again. When it’s been minus 20 degrees Celsius (minus 4°F) outside for weeks.
Phew, I’m glad to live in Germany and feel the effects of global warming. Cold winters are becoming a thing of the past. There may still be regions where it gets cold for longer periods (for example, low mountain ranges), but experiencing minus 20 degrees Celsius (minus 4°F) over widespread areas during the day for weeks is no longer common.

Coldest winters in Germany: bar chart with years and negative temperatures


The severe cold spells you mentioned occurred in 1929 and 1956. According to the German Weather Service (DWD), such extremes happen roughly every 50 to 100 years during what is now a much warmer winter season.

Better head back to the local pub tonight. Your pub talk will probably be better received there without much questioning ;-)
F
Fabian80
15 Sep 2023 13:43
Hello,
what is the circulation pump called in the menu, and why should I turn it off or let it run once a day?
Should the optimization be switched off as well? Or is that the circulation pump? This is in connection with photovoltaic.

I have set water heating blocking times,

Blocked from Mon to Sun
16:30 to 9:30 (I have a photovoltaic system oriented to the east).
I set the hot water temperature to 46°C (115°F) with a 6°C (11°F) hysteresis.
I also adjusted the heating curve from 34 to 28.

What else do I need to set or should set?
Here are my current settings










































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































Commissioning

Heat pump

















15.9.2023

13:42







Serial number









KD index









Serial number









KD index





























IP









Subnet mask









Broadcast









Gateway



















System status:









Heat pumps

Type

LD7





Software version

V2.88.3







Revision

9717







Control panel

1003







Bivalence

Level

1





Operating status

----

















System

Setting:







Utility block (EVU lock)

none

ZWE





Room station

No







Integration

Return flow







Mixing circuit

1

No





Mixing circuit

2

No





Mixing circuit

3

No





ZWE1

Type

Electric heater





ZWE1

Function

Heating

and

Hot water

ZWE1

Power

6.0

kW



ZWE2

Type

No





ZWE2

Function

No





ZWE3

Type

No





ZWE3

Function

No





Error

none

ZWE





Hot water sensor 1

Sensor







Hot water sensor 2

ZIP







Hot water sensor 3

with

ZUP





Hot water sensor 4

Setpoint







Hot water sensor 5

with

HUP





Hot water + heat pump

max

0.0

h



Pump optimization

Yes







Access

KD







VD monitoring

On







Control

Heating circuit

Outdoor temperature dependent





Control

Mixing circuit 1

Outdoor temperature dependent





Control

Mixing circuit 2

Outdoor temperature dependent





Control

Mixing circuit 3

Outdoor temperature dependent





Boost heating

with

Mixing





Electric

Anode

No





Heating limit

Yes







Parallel operation

No







Remote maintenance

No







Pump optimization

Time

180

min



Efficiency pump

Yes







Heat quantity

Cooling circuit







Solar controller

Temperature difference







Message

TDI

Yes





Multi-storage

No







Release

ZWE

60

min



Hot water

Reheating

No





Hot water

Reheat

max

5.0

h

Smart

Grid

No





Control

Mixing circuit 1

fast





Control

Mixing circuit 2

fast





Control

Mixing circuit 3

fast















Temperatures

:







Temperatures:









Return flow limit

50.0°C (122°F)







Hysteresis

HR

2.0

K



TR

Increase

max

7.0

K

Release

ZWE

-2.0°C (28°F)





Temperature air cut-off

7.0°C (45°F)







TDI setpoint temperature

65.0°C (149°F)







Hysteresis

Hot water

6.0

K



Outdoor temperature

max

40.0°C (104°F)





Outdoor temperature

min

-20.0°C (-4°F)





T-LABT end

6.0°C (43°F)







Setback

up to

-20.0°C (-4°F)





Flow temperature

max.

70.0°C (158°F)





Temperature difference

On

4.0

K



Temperature difference

Off

2.0

K



Temperature difference

Storage

max

70.0°C (158°F)



TEE

Heating

2.0

K



TEE

Hot water

5.0

K



Minimum

AT

Flow temperature

max.

-7.0°C (19°F)

Flow temperature

Ground floor

62.0°C (143°F)





Max. hot water temperature

65.0°C (149°F)







Minimum

Return flow setpoint temperature

15.0°C (59°F)





Night setback

Heating circuit

0.0°C (32°F)















Heating limit:









Heating limit

17.0°C (63°F)

















Efficiency pump:









Efficiency pump

Nominal

8.25

V



Efficiency pump

Minimum

8.25

V



Efficiency pump

Yes







Heat quantity

Cooling circuit

















Priorities

:







Hot water

1







Heating

2

















System configuration

:







Heating

1







Hot water

1







Swimming pool

0

















Heating curves

Heating

28.0°C (82°F)

20.0°C (68°F)

0.0K











Information

Operating hours:







Operating hours

VD1

5588h





Impulses

Compressor

1

18645



Run time

Average

VD1

00:17



Operating hours

ZWE1

5h





Operating hours

Heat pump

5588h





Operating hours

Heating

4738h





Operating hours

Hot water

850h

























Information

Temperatures:







Flow temperature

28.7°C (84°F)







Return flow

28.0°C (82°F)







Return flow setpoint

19.6°C (67°F)







Hot gas

40.4°C (105°F)







Outdoor temperature

20.8°C (69°F)







Average temperature

14.8°C (58°F)







Hot water actual temperature

46.1°C (115°F)







Hot water setpoint temperature

46.0°C (115°F)







Heat source input

32.4°C (90°F)







Solar collector

5.0°C (41°F)







Solar storage

150.0°C (302°F)







External

Energy source

5.0°C (41°F)





Flow temperature

max.

70.0°C (158°F)





Suction

VD

41.0°C (106°F)





Suction evaporator

29.3°C (85°F)







VD heating

51.8°C (125°F)







Superheat

12.2

K





Superheat

Setpoint

8.0

K























Yes

=

Yes















Shutdowns:









14.09.23

22:05

none

Start



14.09.23

10:12

none

Start



13.09.23

21:38

none

Start



13.09.23

04:47

none

Start



12.09.23

13:40

none

Start























Calibration

:







NTC1



0.0





NTC2



0.0





NTC3



0.0





NTC4



0.0





NTC5



0.0





NTC6



0.0





NTC7



0.0





NTC8



0.0





































F
Fabian80
15 Sep 2023 13:58
One more addition: I use thermostats