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Author Topic: Ground Source Heatpump Power Consumption  (Read 11388 times)
dhaslam
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« Reply #30 on: April 14, 2014, 10:33:28 AM »

No mention of insulated floors even though I showed the guy the insulation and he took pictures. Also walls down as solid.

That confirms the need for  independent professionals to carry out assessments, otherwise they are pointless.    Although it would add to  the  expense  it is probably what you need  to arrange now  unless  you can  persuade  them to review their report. 

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Ted
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« Reply #31 on: April 14, 2014, 10:58:01 AM »

The deemed kWh for domestic GSHP is based on the EPC figure for the property adjusted by the SPF of the actual installation (given by the MCS installer). There is a worked example (but using ASHP rather than GSHP) here: https://www.ofgem.gov.uk/key-term-explained/seasonal-performance-factor-spf and more info here http://www.microgenerationcertification.org/images/MCS%20021%20-%20Heat%20Emitter%20Guide%20v1.0%202013.12.16.pdf
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marshman
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« Reply #32 on: April 14, 2014, 11:21:57 AM »

Thanks for the info Ted.

 So as I understand it if I take the EPC figure as is, get an MCS guy in to do all the calculations and come up with a SPF (say 3.2 for a GSHP)  do the math and come up with a SPF of 0.68

Taking the EPC figure of 30546kWh per year and the SPF I end up with  20771.28kWh

GSHP RHI of 18.8p / kWh

Gives an annual RHI payment of 3909.00 for 7 years.

The down side is I assume I have to have a GSHP sized to give that sort of insane heat output which will cost more?

One last question do I have to do anything else in terms of installing energy saving measures before installing the GSHP and claiming RHI?

Do I rigorously persue the EPC and try to get the figure down?

Thanks





S

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3.15kWpk (15xSharp ND210)/SB3000. & 3.675kWpk (15 x Suntech 245WD)/SB4000TL, 10kW GSHP driving Wirsbo underfloor heating from 1200m ground loops. 10' x 7' solar wall (experimental). Clearview 650 Wood Burning Stove. MHRV - diy retrofit. Triple glazing.
Ted
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« Reply #33 on: April 14, 2014, 11:36:46 AM »

You will also get something for the DHW heated by the GSHP. The only other thing you will need to do is to meet any loft and cavity wall insulation requirements if these are specified on your EPC. If you need to do these then you will need another EPC after the work has been carried out to certify that it has been done.
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« Reply #34 on: April 14, 2014, 12:13:06 PM »

You will also get something for the DHW heated by the GSHP. The only other thing you will need to do is to meet any loft and cavity wall insulation requirements if these are specified on your EPC. If you need to do these then you will need another EPC after the work has been carried out to certify that it has been done.

Thanks Ted,

On the EPC I can only see "Recommendations", nothing called "Requirements" can I assume that there is nothing I "MUST" do?

Roger
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Ted
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« Reply #35 on: April 14, 2014, 02:06:53 PM »

Yes, they are headed 'Recommended measures' on the EPC - but only the loft and cavity wall insulation items apply as requirements for the RHI.


* recommendations.png (30.25 KB, 731x162 - viewed 248 times.)
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AlanIOW
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« Reply #36 on: April 14, 2014, 05:12:25 PM »

Thanks for the info Ted.

 So as I understand it if I take the EPC figure as is, get an MCS guy in to do all the calculations and come up with a SPF (say 3.2 for a GSHP)  do the math and come up with a SPF of 0.68

Taking the EPC figure of 30546kWh per year and the SPF I end up with  20771.28kWh

GSHP RHI of 18.8p / kWh

Gives an annual RHI payment of 3909.00 for 7 years.

The down side is I assume I have to have a GSHP sized to give that sort of insane heat output which will cost more?

One last question do I have to do anything else in terms of installing energy saving measures before installing the GSHP and claiming RHI?

Do I rigorously persue the EPC and try to get the figure down?


Hi

The SPF for Heat Pump installations is calculated solely from the Radiator/UFH flow temp from the Heat Emitter Guide - http://www.microgenerationcertification.org/images/MIS_3005_Supplementary_Information_2_-_Heat_Emitter_Guide_v2.0_Print_Version.pdf

So if your flow temp is 40 Degrees with a GSHP you will be assigned an SPF of 4.1 [3.4 with an ASHP], this gives a correction factor of 0.756 for the Calculation of renewable heat = 23095kWh = 4341 a yr = 30,393 in total.

If you pursue a lower EPC figure, you may help your pride, but you will get less RHI. The only advantage of a lower EPC figure would be if you were selling your property, which you are obviously not.

Alan

PS Your EPC figure will have no bearing on the size of the heat pump, your MCS installer will work that out from heat loss calcs.
« Last Edit: April 14, 2014, 06:33:49 PM by AlanIOW » Logged

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dhaslam
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« Reply #37 on: April 14, 2014, 05:56:01 PM »

The only problem is that you will need to employ a magician  who can insert  the insulation in your "solid" walls and fit an  insulating block on the inner leaf.    It is no harm to  have a ground loop that is a bit oversize.   If the  GSHP has to be very large you should  be able to use a twin compressor model.  They keep down the starting amps  and  can run on a single compressor.   
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Heating  180,000 litre straw insulated seasonal store, 90X58mm tubes + 7 sqm flat collectors, 1 kW VAWT, 3 kW heatpump plus Walltherm gasifying stove
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« Reply #38 on: April 14, 2014, 09:26:11 PM »

The only problem is that you will need to employ a magician  who can insert  the insulation in your "solid" walls and fit an  insulating block on the inner leaf.

Why???  I already have cavity walls and the cavity is filled - it's just the "system" / assessor thinks that it is better/more accurate to report them as solid due to their "apparent construction" - if necessary I will cut a section out to prove it to them.  As I understand it the only requirement for RHI is you have a minimum of 250mm of loft insulation and cavity wall insulation.

Roger

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marshman
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« Reply #39 on: April 14, 2014, 09:31:59 PM »


Hi

The SPF for Heat Pump installations is calculated solely from the Radiator/UFH flow temp from the Heat Emitter Guide - http://www.microgenerationcertification.org/images/MIS_3005_Supplementary_Information_2_-_Heat_Emitter_Guide_v2.0_Print_Version.pdf

So if your flow temp is 40 Degrees with a GSHP you will be assigned an SPF of 4.1 [3.4 with an ASHP], this gives a correction factor of 0.756 for the Calculation of renewable heat = 23095kWh = 4341 a yr = 30,393 in total.

If you pursue a lower EPC figure, you may help your pride, but you will get less RHI. The only advantage of a lower EPC figure would be if you were selling your property, which you are obviously not.

Alan

PS Your EPC figure will have no bearing on the size of the heat pump, your MCS installer will work that out from heat loss calcs.

Thanks for that Alan, kind of confirms what I thought - I think my pride can live with it, though it is frustrating the system doesn't allow accurate reporting.

Spoke to a "local" installer who is awaiting his MCS paperwork and he said most of the right things and is coming down for a "quick" look next week. One thing he did say was that he had read that although the RHI was initially based on the deemed heat requirement from the EPC a heat meter would become necessary after 2015. He couldn't remember where he had read it but he was fairly adamant about it.

Roger
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3.15kWpk (15xSharp ND210)/SB3000. & 3.675kWpk (15 x Suntech 245WD)/SB4000TL, 10kW GSHP driving Wirsbo underfloor heating from 1200m ground loops. 10' x 7' solar wall (experimental). Clearview 650 Wood Burning Stove. MHRV - diy retrofit. Triple glazing.
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