Surplus management not ideal for single-phase heat pump

[CiNcH83]

Description

With the heat pump being single phase, min. power can only be set as high as 3,5 kW for surplus management. In case of a DHW Boost, the heat pump quickly reaches 3,4 kW, resulting in evcc switching between Boost and Normal frequently in the morning due to fluctuations in production and house loads.

There are several possible workarounds for that. One would be to make the heat pump 3-phase (even though it is not) and set min. power to 4,1 kW. Unfortunately there is nothing between 3,5 kW and 4,1 kW. Another one is to use the custom surplus mechanism and either increase the threshold or delay.

Steps to Reproduce

1. set min. power to 3,5 kW
2. wait for enough surplus
3. boost activated - heat pump quickly draws 3,4 kW

Configuration (YAML)

log: trace

Configuration (UI)

{
  "charger": [
    {"id":7,"name":"db:7","config":{"host":"192.168.1.15","icon":"bike","standbypower":"15","template":"tplink"},"deviceProduct":"TP-Link H-Series Smart Plug","type":"template"},
    {"id":4,"name":"db:4","config":{"password":"***","realm":"DE","template":"vaillant","user":"***"},"deviceProduct":"Vaillant SensoNET (API)","type":"template"}
  ],
  "circuits": "- name: main
  title: Hauptstromkreis
  maxCurrent: 35
  maxPower: 24150
  meter: db:1",
  "experimental": true,
  "influx": {"url":"","database":"","token":"","org":"","user":"","password":"","insecure":false},
  "interval": 15,
  "loadpoints": [
    {"id":5,"name":"db:5","batteryBoostLimit":100,"charger":"db:4","defaultMode":"pv","limitEnergy":0,"limitSoc":55,"maxCurrent":15,"meter":"db:6","minCurrent":15,"phasesConfigured":1,"planEnergy":0,"planPrecondition":0,"planStrategy":{"continuous":false,"precondition":0},"planTime":"0001-01-01T00:00:00Z","priority":0,"smartCostLimit":null,"smartFeedInPriorityLimit":null,"soc":{"poll":{"mode":"charging","interval":3600000000000},"estimate":true},"thresholds":{"enable":{"delay":60000000000,"threshold":0},"disable":{"delay":180000000000,"threshold":0}},"title":"aroTHERM plus"},
    {"id":8,"name":"db:8","batteryBoostLimit":100,"charger":"db:7","defaultMode":"off","limitEnergy":0,"limitSoc":0,"maxCurrent":1,"minCurrent":1,"phasesConfigured":1,"planEnergy":0,"planPrecondition":0,"planStrategy":{"continuous":false,"precondition":0},"planTime":"0001-01-01T00:00:00Z","priority":0,"smartCostLimit":null,"smartFeedInPriorityLimit":null,"soc":{"poll":{"mode":"charging","interval":3600000000000},"estimate":true},"thresholds":{"enable":{"delay":60000000000,"threshold":0},"disable":{"delay":180000000000,"threshold":0}},"title":"eBike Charger","vehicle":"db:9"}
  ],
  "meter": [
    {"id":2,"name":"db:2","config":{"baudrate":9600,"comset":"8N1","forceaccharging":"false","host":"192.168.1.12","id":1,"maxacpower":8000,"maxchargepower":"10000","modbus":"tcpip","port":502,"storageunit":"1","template":"huawei-sun2000","timeout":15000000000,"usage":"pv"},"deviceProduct":"Huawei SUN2000","deviceTitle":"SUN2000","type":"template"},
    {"id":1,"name":"db:1","config":{"baudrate":9600,"comset":"8N1","forceaccharging":"false","host":"192.168.1.12","id":1,"maxacpower":"0","maxchargepower":"10000","modbus":"tcpip","port":502,"storageunit":1,"template":"huawei-sun2000","timeout":15000000000,"usage":"grid"},"deviceProduct":"Huawei SUN2000","type":"template"},
    {"id":3,"name":"db:3","config":{"baudrate":9600,"capacity":5,"comset":"8N1","forceaccharging":true,"host":"192.168.1.12","id":1,"maxacpower":"0","maxchargepower":2500,"maxdischargepower":2500,"maxsoc":100,"minsoc":4,"modbus":"tcpip","port":502,"storageunit":"1","template":"huawei-sun2000","timeout":15000000000,"usage":"battery"},"deviceProduct":"Huawei SUN2000","deviceTitle":"LUNA2000","type":"template"},
    {"id":6,"name":"db:6","config":{"ski":"***","template":"eebus-mpc","usage":"charge"},"deviceProduct":"EEBus Verbraucher","type":"template"}
  ],
  "modbusproxy": [{"port":5021,"readonly":"false","settings":{"uri":"192.168.1.15:502","rtu":false}}],
  "mqtt": {"broker":"","user":"","password":"","clientID":"","insecure":false,"caCert":"","clientCert":"","clientKey":"","topic":"evcc"},
  "shm": {"vendorId":"","deviceId":"","deviceSerial":""},
  "site": {"title":"HEMS","grid":"db:1","pv":["db:2"],"battery":["db:3"],"aux":null,"ext":null},
  "tariff": [
    {"id":11,"name":"db:11","config":{"price":0.0643,"template":"fixed"},"deviceProduct":"Fixed Price","type":"template"},
    {"id":10,"name":"db:10","config":{"price":0.3,"template":"fixed"},"deviceProduct":"Fixed Price","type":"template"},
    {"id":12,"name":"db:12","config":{"template":"grünstromindex","zip":"***"},"deviceProduct":"Grünstromindex","type":"template"},
    {"id":13,"name":"db:13","config":{"ac":1000,"alphatemp":"-0.004","az":-10,"de":"0","dec":25,"dm":"0","efficiency":80,"interval":"1h","kwp":6.075,"lat":"***","lon":"***","rossmodel":"0.0342","template":"open-meteo"},"deviceProduct":"Open-Meteo","deviceTitle":"Steildach","type":"template"},
    {"id":15,"name":"db:15","config":{"ac":"1000","alphatemp":"-0.004","az":-10,"de":"0","dec":6,"dm":"0","efficiency":80,"interval":"1h","kwp":3.24,"lat":"***","lon":"***","rossmodel":"0.0342","template":"open-meteo"},"deviceProduct":"Open-Meteo","deviceTitle":"Flachdach","type":"template"}
  ],
  "tariffRefs": {"grid":"db:10","feedIn":"db:11","co2":"db:12","planner":"","solar":["db:13","db:15"]},
  "vehicle": [
    {"id":9,"name":"db:9","config":{"capacity":0.75,"icon":"bike","template":"offline","title":"CUBE Kathmandu"},"deviceProduct":"Generisches Fahrzeug (ohne API)","type":"template"}
  ]
}

Logs

I am attaching a log, illustrating the issue. There have admittedly been clouds passing through. But I have seen this behaviour even without clouds.

evcc.log

Version

v0.303.2 (9b7add3)

System

linux/arm64, CET +01:00

[CiNcH83]

While comparing the standard and custom surplus management modes for heat pump boosting, I realized that surplus seems to be calculated differently for the two modes...

standard: power consumption heat pump + battery charging + grid export
custom: battery charging + grid export

[andig]

With the heat pump being single phase, min. power can only be set as high as 3,5 kW for surplus management.

What makes you say so?

[CiNcH83]

Or do I actually have to set it here:

Seems like I am not educated well enough to properly set up surplus management?

[andig]

The latter is the static limit, the former the user override. Obviously, if you set a 15A static limit, the user will not be able to go above/below static limits.

@naltatis I notice that the user limits don't seem to honor the static limits- not sure why? Is this intentional?

[CiNcH83]

Thanks, got it. Not super intuitive though. One has to set the static limits to values that the heat pump doesn't even support just to be able to increase hysteresis...

I now set the static limits higher and can therefore also set min. power higher for surplus management.

Standard surplus management indeed seems better than custom as it also takes the current power consumption of the heat pump into consideration for surplus calculation.

[andig]

One has to set the static limits to values that the heat pump doesn't even support just to be able to increase hysteresis...

Can you elaborate? Static limits are the boundaries of user limits (or rather: should be). What exactly is the issue?

Standard surplus management indeed seems better than custom as it also takes the current power consumption of the heat pump into consideration for surplus calculation.

...which I keep repeat saying...

[CiNcH83]

Can you elaborate?

My heat pump supports 15A max. (3,5 kW). When a boost starts, it quickly reaches those 3,5 kW. So when boost starts at a surplus of 3,5 kW it happens a lot that boost is switched on and off multiple times due to missing hysteresis, also see attached log. When the log has been captured, clouds passed through. But I have seen this back and forth between boost on and off even without clouds due to varying house loads. I therefore set min. power to like 3,7 or 3,9 kW so this happens less frequently (with custom, I even increased the delays). And for that to happen I have to set static limits to values that the heat pump does not even support.

[andig]

due to missing hysteresis

We have configurable delays for that. Whats wrong with those?

[CiNcH83]

Thought those can only be changed for custom mode?

[naltatis]

@naltatis I notice that the user limits don't seem to honor the static limits- not sure why? Is this intentional?

We have not differentiation between user or static limits. Both places (loadpoint settings modal and config ui) should read/write to min|maxcurrent of the loadpoint.
@CiNcH83 Is this not the case?

[CiNcH83]

It is kind of weird. I first had to increase the current range in config ui to get more settings (>15A for single-phase) in the loadpoint ui. When I now set the desired min. power in the loadpoint ui for proper surplus management, the values also get set in the config ui.