Posted by: @iantelescope

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@jamespa 

 

House cooling:

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I disconnected the shorting wire at 1400 today while keeping the [+15:25] Water Law settings.

The Water Temperature operated between 24 and 30 C being set to operate between 25 and 30 C.

I left to go for an optical appointment returning at 1700.

The Water Temperature having dropped to 20 C by 1700 loosing much of the  house residual heat.

I then reset the [+15:25 ] to my original [+15:35] again without any house temperature increase.

Finally, I increased the Water Law offset to +3 C with the resulting leap in Temperature from 20 C to 36 C.

My Room , being still cold, I started a 600 Watt Electric fire finally reaching 22.5 C room temperature.

The power taken during this episode was :

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Showing no power consumed between 1500 and 1730.

Outside temperature still falling .....12.7 C.

 

Conclusion:

Any heating system must have sufficient power to increase the room Temperature in a reasonable time following a break in the energy supply.

A backup 1.5 kw Immerser heater element  inserted into the Buffer perhaps ?

 

 

 

 

 

 

 

Switching off and then raising the flow temperature to reheat is very inefficient and will cost you money.  Please don't do this.

Please leave your system on 24*7 with the flow temperature parameters provided by Derek, the thermostat shorting wire in place, all your trvs fully open, and the buffer tank out of circuit.  This, once the water law parameters are correctly tuned, is the most efficient way to operate and will give you the nice stable temperature you need

If the power fails by all means use a small electric heater to give a boost, or use the offset function for the flow temperature to turn it up temporarily.  Hopefully that is a rare occurrence.

Once the system is operating stably on weather compensation 25*7 we can look at whether any further tweaks are worthwhile.

Heat pumps need to be operated more or less continuously at the minimum possible flow temperature to give minimum cost.  Actually the same is true, albeit to a lesser extent, of modern condensing boilers, but unfortunately the industry in the UK is only now, and only partly, admitting this, having made a fortune out of selling us 'smart' controls which cost money and reduce comfort.

If the heat emitters are not sized correctly and more critically the system not balanced correctly you are wasting your time doing this.

What Derek suggested doing should have resulted in a stable system output unless the heatpump is way oversized resulting in cycling, or the energy is not being transferred to the emitters correctly. ( balance issue). 

Posted by: @johnmacleod10

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What Derek suggested doing should have resulted in a stable system output unless the heatpump is way oversized resulting in cycling, or the energy is not being transferred to the emitters correctly. ( balance issue). 

So far as @iantelescope has reported it did result in a stable temperature, more or less the value desired. 

Unfortunately @iantelescope  then turned the heat pump off for a while and then changed the WC parameters and reinstated the problem thermostat for reasons best known to himself.

We don't yet know whether the system is oversized, there are other issues obscuring it's performance detailed in the past 67 pages which Derek and and I have been trying to persuade Ian to rectify step by step.

@iantelescope

Switching off and then raising the flow temperature to reheat is very inefficient and will cost you money.  Please don't do this.

Please leave your system on 24*7 with the flow temperature parameters provided by Derek, the thermostat shorting wire in place, all your trvs fully open, and the buffer tank out of circuit.  This, once the water law parameters are correctly tuned, is the most efficient way to operate and will give you the nice stable temperature you need

If the power fails by all means use a small electric heater to give a boost, or use the offset function for the flow temperature to turn it up temporarily.  Hopefully that is a rare occurrence.

Once the system is operating stably on weather compensation 25*7 we can look at whether any further tweaks are worthwhile.

Heat pumps need to be operated more or less continuously at the minimum possible flow temperature to give minimum cost.  Actually the same is true, albeit to a lesser extent, of modern condensing boilers, but unfortunately the industry in the UK is only now, and only partly, admitting this, having made a fortune out of selling us 'smart' controls which cost money and reduce comfort.

@jamespa & @derek--m

!! Negative loss !!

My Energy loss for yesterday , incredibly, show an negative loss:

This Negative loss is caused by the release of the Energy stored within the Buffer tank.

The COP , as measured at the Heat Pump and the COP as measured at the start of the Radiator circuit, also show the Energy stored within the Buffer tank:

The negative loss , or the release of  energy stored within the buffer producing an output COP greater than the COP indicated by the Heat Pump itself!

Both COP Measurements, however,  show a drop in absolute values with the Thermostat shorted.

Power, as a function of time ,with the Thermostat shorted show :

The Later power runs with the Thermostat Short removed show:

The Buffer tank may have it's uses in providing a residual store of energy, both during, and after a power cut.

The Average Cycle and Run times were dominated by the Thermostat operation.

The reduction in Cycle Timing following the Shorting of the Thermostat is  shown in the previous days results..

Finally, the energy consumption , now confirmed by Octopus as ~10 Kw h, is:

I will ,today return to shorting of the Thermostat.

I have switched the buffer OFF.

I will return the results tomorrow , allowing for the large response times caused by the  limited power, 410 Watts,  supplied by the Heat Pump .

Posted by: @iantelescope

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I will ,today return to shorting of the Thermostat.

I have switched the buffer OFF.

I will return the results to-morrow , allowing for the large response times caused by the  limited power, 410 Watts,  supplied by the Heat Pump .

Thank you.

Please also reset the water law coordinates to the ones provided by Derek

Please do not switch the heat pump off if you go out or for any other reason (except emergency, obviously)

Please make sure all TRVs are fully open (if you need to close one in a bedroom to make it slightly cooler thats OK).

Once the house has stabilised please measure again the deltaT between flow (from the heat pump) at the input to the heat exchanger and flow (to the radiators) at the output of the heat exchanger so we can be certain what penalty this is currently causing.

Also, is the energy 'confirmed by Octopus' your total electricity consumption, or do they have a separate meter for the heat pump?

You are right that it will take a day to stabilise, that's perfectly normal.  In fact it may take even longer still for the fabric of the house to reach equilibrium.  Please do nevertheless check back here a couple of times in case we have any further thoughts/need to ask any further questions.

Buffer tanks do not store sufficient energy to cover a power outage of any material duration, the house fabric is your best energy store for this purpose.  The energy they store can however be useful in defrosting (when it gets colder!) but they need to be plumbed correctly otherwise they reduce efficiency.  

You cant yet make any deductions about COP given that the system has not been allowed to stabilise.  Please do as requested above, and then leave it alone for several days, otherwise any measurements of energy consumption are almost totally meaningless.  Hopefully you have a record of OAT also during the period.

@iantelescope

How are you measuring the Power as shown in the graph?

@iantelescope

Could you please clarify why your heat pump stopped functioning yesterday afternoon.

@jamespa & @derek-m

Samsung sensor Maps by Timothy Pont

@derek-m  Please look at the map of my Samsung with the Temperature Sensors added.

The Temperature sensors :

Sen1 = From Heat Pump

Sen2 = Heat Pump Return

Sen3 = Heat Exchanger Primary input

Sen4 = Heat Exchanger Primary output

Sen6 = Buffer Tank

Sen7 = Output to Radiators

Sen8 = Radiators Return

Sen9 = Sharky Water Meter Temperature Outgoing

Sen10 = Sharky Water Meter Temperature Return.

Power sensors

Sharky Power meter

Sharky Energy meter

Flow meters

Sharky flow meter on Radiators Secondary

ian

p.s. will somebody name a program running under linux enabling the production of proper piping diagrams .....not libreoffice

Posted by: @iantelescope

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p.s. will somebody name a program running under linux enabling the production of proper piping diagrams .....not libreoffice

 

Plus one for that, or even under windows for me.  I use Libreoffice but it's a pita for this purpose.

@iantelescope

Many thanks.

If possible could you please provide graphs for each sensor along with IAT and OAT graphs, over 4 hour periods.

If that is not possible could you please supply a table of readings for the above at reasonable time intervals, say every 10 minutes or so.

Such data would allow us to better understand what is happening within your system.

Did you keep warm last night?

I have always thought the volumiser should be plumbed in series with the secondary heat exchanger and not in parallel with it (as shown in @iantelescope diagram above). Am I missing something?