New GSHP Efficiency?

markin

MikeJXE said:

MattMattMattUK the pipes were installed as slinkys. To you and me a 'slinky' is simply a coiled pipe acting as a heat collector laid in an array of 4no. 1m deep trenches x 60m long.

I don't know a single thing about heat pumps but I do know about trenches

Is 1m deep enough ?

I have worked in many trenches and you don't get any heat at 1 metre, heck water services have to be 75cm deep or they are liable to freezing 

I would have thought 2m or 2.4m would have been a minimum depth as I know it's much warmer there ? 

It did sound a little shallow to me but it must be ok as its getting an average COP of 3.96.

MikeJXE

markin said:

MikeJXE said:

MattMattMattUK the pipes were installed as slinkys. To you and me a 'slinky' is simply a coiled pipe acting as a heat collector laid in an array of 4no. 1m deep trenches x 60m long.

I don't know a single thing about heat pumps but I do know about trenches

Is 1m deep enough ?

I have worked in many trenches and you don't get any heat at 1 metre, heck water services have to be 75cm deep or they are liable to freezing 

I would have thought 2m or 2.4m would have been a minimum depth as I know it's much warmer there ? 

It did sound a little shallow to me but it must be ok as it's getting an average COP of 3.96.

A COP of 3.96 means nothing to me but walking down a 60m long 2m deep trench and feeling the warmth does 

Reed_Richards

kwoodberry said:

The house is large (~4000 sq ft) 

The EPC states the following:
The primary energy use for this property per year is 54-kilowatt hours per square metre (kWh/m2).

I presume the EPC figure is the annual usage, 54 kWh per sq. metre per year?  So what's that for the whole house?

MikeJXE

Reed_Richards said:

kwoodberry said:

The house is large (~4000 sq ft) 

The EPC states the following:
The primary energy use for this property per year is 54-kilowatt hours per square metre (kWh/m2).

I presume the EPC figure is the annual usage, 54 kWh per sq. metre per year?  So what's that for the whole house?

24,000 kWh

markin

Reed_Richards said:

kwoodberry said:

The house is large (~4000 sq ft) 

The EPC states the following:
The primary energy use for this property per year is 54-kilowatt hours per square metre (kWh/m2).

I presume the EPC figure is the annual usage, 54 kWh per sq. metre per year?  So what's that for the whole house?

371sqm = 20,034 kwh ?

MikeJXE

markin said:

Reed_Richards said:

kwoodberry said:

The house is large (~4000 sq ft) 

The EPC states the following:
The primary energy use for this property per year is 54-kilowatt hours per square metre (kWh/m2).

I presume the EPC figure is the annual usage, 54 kWh per sq. metre per year?  So what's that for the whole house?

371sqm = 20,034 kwh ?

Reed_Richards said:

kwoodberry said:

The house is large (~4000 sq ft) 

The EPC states the following:
The primary energy use for this property per year is 54-kilowatt hours per square metre (kWh/m2).

I presume the EPC figure is the annual usage, 54 kWh per sq. metre per year?  So what's that for the whole house?

Yeah much closer 20,034

markin

20,034 / 5 months of heating = 4006, so 1000 kwh a month at a Cop 4 ?

Cop 4 means 1kwh in 4kwh of heat out.

Reed_Richards

If it was 1000 kWh per month (for 5 months) that would be £340 month (for those 5 months) if you are on the SVT and that's just your space heating.

Then there's the hot water on top of that.  It would be interesting to know how much electricity that Plug and Glow heater is consuming.  If the hot water goes round the loop but comes back at less than 48 C it could still be on for most of the hours it is set for.      

matelodave

TBH its unclear that all this leccy is being used by the GSHP., without being able to differentiate what is using it all especially chucking some air conditioning in the external office plus what ever else is being used it's not necessarily fair to blame it onto the GSHP.

Unless there are some records of consumption before the HP was installed or it is possible to record the heating system power consumption then its all just speculation on what is using it all.

kwoodberry

Unfortunately, there are no historical records of consumption as the house is a new-build with a new electric meter. So the usage only really started end of June 2022 when we moved in (apart from the small consumption of lighting and charging trades power tools).

However, I did find the consumption of the GSHP. There's a small display under the main cover.

It reads 5193 kWh to date.

Bearing in mind, the GSHP was fitted new around April 2022, and was only really used from June to October for Domestic Hot Water, the space heating side of it has only really been running since late October 2022.

Would you say this is "as expected" consumption, or high, considering the leccy meter only reads 12352 kWh (as of yesterday)?

I will check the GSHP consumption screen weekly as I make the odd tweak, like reducing the amount of time the DHW is set to come on for.