Well this might be a coincidence but after upping my pressures my system is looking more stable today
https://emoncms.org/app/view?name=My%20Heatpump&readkey=e823421627534c76bd0db163b4e60a5c
Interesting data Chris.
It does look more stable.
I have to ask, where is the data coming from?
I am curious, how are you working out the heat being produced?
The sums don’t add up.
Just picked a couple of points from today, dt of 3c and flow of 6.9lpm is not the 3,370W of heat shown. Another one, dT of 4.7c with 6.9lpm flow shows heat produced of 8,798W.
I’m taking the power being used multiplied by the COP
COP is taken from the heatpump data ( espaltherma )
Flow sensor (litres per minute ) x 0.06 x 1.16 x leaving water temp - inlet water temp
Divided by
Inverter primary current x voltage / 1000
Data taken every 30 seconds
That doesn’t appear to be what it is doing?
Presumably inverter primary current is the compressor?
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ooh please inform me what seems to be wrong ,
the only figure which might be out of sink in the calculation is the voltage as this figure is taken from a sensor on my supply and the input power is a independent sensor from the espaltherma integration & is the power of the whole heatpump system
yes i think it is the compressor
what calculation are you both using and is my data consistently wrong ?
Hi Chris,
The first thing is that everybody in this discussion uses total electricity consumption of the heat pump so it includes the controls and the circulation pump. Your system shows as H4 so if it doesn’t include everything then that is not correct.
As far as the heat production shown, I don’t know what is wrong.
It is sometimes showing too little but generally too much based on the dT (flow - return temperature) and flow rate.
At the time of reply your data shows a dT of 3.9c, a flow rate of 7.1 lpm and heat produced of 3,714W
A dT of 3.9c at 7.1 lpm is actually 1,927W
Calculation (7.10 x 0.06 x 1.16 x 3.9)
Try it yourself.
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the power sensor does include everything on the heat pump so that should H4 ? i think
as for the calculation i need to look in to this , my guess is its the sinking of the power and the voltage as these are independent sensors from the heatpump i could change both of these to improve accuracy
ive just checked and these are only updating every minute where the esp altherma is updating every 30 seconds
do you think this could be the issue
I would guess that the problem is using the power consumption in the heat production calculation.
As soon as you look at your data there is clearly a problem, the heat production varies wildly even though the dT and flow rate are pretty steady. Just look at the heat production, huge peaks and troughs.
Through too many hours spent looking at heat pump data I know instantly from dT and flow rate what the heat output should be .
I just know that a dT of 4c at 7lpm is aboout 2,000W of heat.
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ah ok , so i am guessing i cant change this then as i dont think i have heat production from the espaltherma system
hi @Chris_Hill, do the numbers match in HA?
- name: "W Q Heating"
unique_id: "W Q heating"
state_class: measurement
#device_class: power
icon: mdi:radiator
#ΔQ = m° Cp ΔT.
#ΔQ = Rate of heat transfer (kW)
#m° = Mass flow rate (kg/s or LPS)
#ΔT = Temperature difference in Kelvin
#Cp = Specific heat at constant pressure (kJ/kg K) 4.184 J⋅kg−1⋅K−1.
state: >
{{ ((state_attr('sensor.esp_altherma','Flow sensor (l/min)')/60 | float * 4.184 * ((state_attr('sensor.esp_altherma','Leaving water temp. before BUH (R1T)') | float - state_attr('sensor.esp_altherma','Inlet water temp.(R4T)')|float) ) )
|round(2) * 1000) }}
attributes:
minute_counter: "{{ now().minute }}"
availability: "{{ ((states('sensor.flow_sensor_l_min')) | is_number) and ((states('sensor.leaving_water_temp_before_buh_r1t')) | is_number) and ((states('sensor.inlet_water_temp_r4t')) | is_number) }}"
- name: “COP”
unique_id: “espaltherma_cop”
unit_of_measurement: ‘COP’
state: “{% if is_state_attr(‘sensor.althermasensors’,‘Operation Mode’, ‘Heating’) %}
{{
((state_attr(‘sensor.althermasensors’,‘Flow sensor (l/min)’)| float * 0.06 * 1.16 * (state_attr(‘sensor.althermasensors’,‘Leaving water temp. before BUH (R1T)’) | float - state_attr(‘sensor.althermasensors’,‘Inlet water temp.(R4T)’)|float) )
/
(state_attr(‘sensor.althermasensors’,‘INV primary current (A)’) | float * states(‘sensor.myenergi_my_home_voltage_grid_2’)|float / 1000))
|round(2)
}}
{% else %} 0 {%endif%}”
yes the same in HA
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i am going to add this calc to my yaml code for heat produced , i will shout up when i have done it if you wouldn’t mind taking a other look after ive done it , it would be appreciated
What are these constants in the middle?
Neil has / 60 * 4.184 * which looks closer to the physics.
PS: for systems with 25% propylene glycol, the specific heat of the fluid is 4000 at 40°C.
Hi Chris,
I don’t know what is wrong, ESPAltherma is not my thing as you probably know 
But this clearly isn’t correct for many reasons.
I hope somebody can help you sort it out.
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Here is all three options including the one im using now which seems to be over reading
so looks like i can sort it out, thanks for pointing this out , the calculation does look like it is the issue as you previously mentioned
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as this s a live view of the sensors i have been monitoring it for 15 mins and im not getting the bouncing of the out put , so just need to bring all this together , when ive applied it to heat pump monitor i will mention it here and if you wouldent mind taking a look to see if the figures look better
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Hi @Chris_Hill,
Are you using ESPAltherma primary current in your calculations?
If this is so, this is the cause of the inaccuracies:
See here:
You will want to be getting a Heat Pump Power feed from another source (in my case, its the Myenergi setup I already had for the car charger)
Screen grab of the main point in the link:
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Hi Stephen,
Good shout.
The calculation looks correct but the heat output is clearly wrong.
It’s all beyond me so I can’t help other than identifying an issue.
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If using the ESPAltherma data, there is no Power metric, so others have tried using the current and voltage figures presented in the available data (and there are multiple which further muddies the water), but they (for reasons I do not understand) are so wildly different than a separate power meter, it is unusable even for non-MID monitoring IMO
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