ASHP & triple glazing

[Fintray]

Did you go for the full mid metering? Any value in it?

I went MID metering as it is probably the most accurate available and will give you a true picture as to how your system is performing.

Thank you, I have asked for a price on the full bhuna.

The Openenergy monitor is MID metering.

[Stinsy]

Reading this today sent me back to the heat pump monitoring pages to have another look and its surprising to see how flexible some of the set points are. As an example we were advised that running a heat pump low and slow is the best way to get the optimum performance, but on the monitor pages you can see that some pumps with very low flow temps of 35 to 39 degrees and 5kW Hp don't perform as well as say a system with a 45 degree flow temp and an 11kW Hp - so what is making the mid range capacity heat pumps with higher flow temps outperform the smaller ones ?

Moxi

Maybe it is the local environment? I’ve read that HPs in drier areas are more efficient than this in a very damp area. Outdoor temperature varies a lot between Scotland and Cornwall too.

Is there any way to find more about those very-efficient systems?

[HML]

Reading this today sent me back to the heat pump monitoring pages to have another look and its surprising to see how flexible some of the set points are. As an example we were advised that running a heat pump low and slow is the best way to get the optimum performance, but on the monitor pages you can see that some pumps with very low flow temps of 35 to 39 degrees and 5kW Hp don't perform as well as say a system with a 45 degree flow temp and an 11kW Hp - so what is making the mid range capacity heat pumps with higher flow temps outperform the smaller ones ?

Moxi

There are loads of confounding variables and SPF isn't the be all and end all. (https://protonsforbreakfast.wordpress.c ... pointless/ for instance.)

One issue is defrosts. My heat pump is only just big enough and in cool damp weather (most of the winter) it defrosts frequently with a hit to SPF. A larger heat pump with a larger heat exchanger may defrost less frequently. Refrigerant makes a difference, R290 ones like the Vaillant Arotherm plus perform better at below 5C than most R32 heat pumps. Also those SPFs include hot water runs which are generally less efficient. A system with a lot of HW use is likely to perform worse than a system with low HW use.

A big factor is internal temperature. A system that runs at 19C is going to perform better than one that runs at 23C, all things being equal.

You need to look at systems very carefully in order to draw conclusions.

[Joeboy]

Reading this today sent me back to the heat pump monitoring pages to have another look and its surprising to see how flexible some of the set points are. As an example we were advised that running a heat pump low and slow is the best way to get the optimum performance, but on the monitor pages you can see that some pumps with very low flow temps of 35 to 39 degrees and 5kW Hp don't perform as well as say a system with a 45 degree flow temp and an 11kW Hp - so what is making the mid range capacity heat pumps with higher flow temps outperform the smaller ones ?

Moxi

There are loads of confounding variables and SPF isn't the be all and end all. (https://protonsforbreakfast.wordpress.c ... pointless/ for instance.)

One issue is defrosts. My heat pump is only just big enough and in cool damp weather (most of the winter) it defrosts frequently with a hit to SPF. A larger heat pump with a larger heat exchanger may defrost less frequently. Refrigerant makes a difference, R290 ones like the Vaillant Arotherm plus perform better at below 5C than most R32 heat pumps. Also those SPFs include hot water runs which are generally less efficient. A system with a lot of HW use is likely to perform worse than a system with low HW use.

A big factor is internal temperature. A system that runs at 19C is going to perform better than one that runs at 23C, all things being equal.

You need to look at systems very carefully in order to draw conclusions.

Excellent article (and post). I too am an idiot and particularly liked this paragraph,

"I think this result is both surprising and obvious. It’s counter-intuitive because in general a well-insulated home is easier to heat (with a heat pump or in any other way). But it is also quite obvious because the overall COP is the average of the DHW COP and space-heating COPs, and the more space heating that is performed, the better the expected COP."

[Joeboy]

Within that same post in the comments section I found this.

https://community.openenergymonitor.org ... d/21891/20

I should probably have read it through before committing to buy but now at least I have my.own cop of 2 based on worry & fretting to monitor.

[Joeboy]

I went MID metering as it is probably the most accurate available and will give you a true picture as to how your system is performing.

Thank you, I have asked for a price on the full bhuna.

The Openenergy monitor is MID metering.

Ah great, so I don't have a need to pony up for anything extra in the way of monitoring unless that's my thang?

Got this through from George,
"Robbie advised that we can provide you with the Open Energy Monitor and a connection to the web, at no extra charge. The 'full' OEM setup would necessitate another plumbed-in component, which would add cost and time, but if you're happy with the ability to compare SCOP online then that's no problem!"

[Joeboy]

Got this quote for an OEM add on

"Open Energy Monitor Level 3 Heat Pump Monitoring setup.
BUNDLE INCLUDES
MID approved Modbus Electricity Meter
MID approved M-Bus Heat Meter
emonPi Web-connected data logger WiFi & Ethernet connectivity
Modbus RS485 reader (for electricity meter(s))
M-Bus reader (for heat meter)
Power supply and cables
10yrs of free emoncms.org data logging
Supplied and installed - £654.06 (zero VAT when installed as part of the heat pump job)."

Am I correct in saying you went for the lite version Iain as part of the install rather than all the above ?

[Fintray]

Thank you, I have asked for a price on the full bhuna.

The Openenergy monitor is MID metering.

Ah great, so I don't have a need to pony up for anything extra in the way of monitoring unless that's my thang?

Got this through from George,
"Robbie advised that we can provide you with the Open Energy Monitor and a connection to the web, at no extra charge. The 'full' OEM setup would necessitate another plumbed-in component, which would add cost and time, but if you're happy with the ability to compare SCOP online then that's no problem!"

By the sounds of that reply they are not intending to install a heat meter which you need to be able to calculate the COP.
For the couple of hundred quid or so I would go for the full kit but that is purely your decision, it would be a pain to then decide to get it fitted later.

This is the full kit https://shop.openenergymonitor.com/leve ... le-emonhp/, I see they are using a different model of heat meter now which now works out cheaper than what mine cost.

Edit - Joe what you have noted in the previous post is what I installed.

[Joeboy]

The Openenergy monitor is MID metering.

Ah great, so I don't have a need to pony up for anything extra in the way of monitoring unless that's my thang?

Got this through from George,
"Robbie advised that we can provide you with the Open Energy Monitor and a connection to the web, at no extra charge. The 'full' OEM setup would necessitate another plumbed-in component, which would add cost and time, but if you're happy with the ability to compare SCOP online then that's no problem!"

By the sounds of that reply they are not intending to install a heat meter which you need to be able to calculate the COP.
For the couple of hundred quid or so I would go for the full kit but that is purely your decision, it would be a pain to then decide to get it fitted later.

This is the full kit https://shop.openenergymonitor.com/leve ... le-emonhp/, I see they are using a different model of heat meter now which now works out cheaper than what mine cost.

Edit - Joe what you have noted in the previous post is what I installed.

Cheers Iain, some Scaletrix set this is turning into!

Sorry about the heat meter dunt. You've been a great help, not sure I'd have stepped off the edge of indecision without you going first.
19 days to install commencing.

[Joeboy]

Still playing with the SH times and managed to end yesterday in profit.