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Replacing Worcester oil boiler with an ASHP

JulianC · 2021-03-30T18:15:26Z

I am replacing my 25/32 Worcester oil boiler with an ASHP Had discussions with many suppliers, a lot of whom wouldn't quote because we have 10mm pipe drops to each radiator, from 28mm loft pipes. Anyway: 201m2 bungalow. Built 2001. EPC rating of B after triple glazing, 300mm of loft insulation. We currently use between 1220-1500L of oil per annum. 100A incoming circuit. ASHP approved by DNO (Western Power). 20,500kWh of heating energy required. 3000kWh of hot water demand from the EPC. An energy loss calc and room by room heat demand has been undertaken. This has lead me to select Ecobubl from Winchester to undertake the work. They have proposed a Daikin Altherma 3H HT 18kW ASHP. Also a Mixergy 150L H/W tank - but we are also considering a standard cylinder with a large internal coil, to maximise the ASHP. And a 3kW immersion to use my 4kW of PV and Solic 200 electric diverter. Simple control system, using my current Nest. Had wondered about the Homely Energy control system, but I wonder if this adds complexity. Price is £13,700 for ASHP + Mixergy + buffer tank + installation and support for RHI. I should get back about £10k through RHI. I will take photos before, during and after installation which should be 12 April

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Air Source Heat Pumps (ASHPs)

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Morgan

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15/01/2022 3:24 pm

@julianc first time I saw mine do it I thought it had caught afire. Quite a shock before realising what was happening and the ‘smoke’ was actually steam. 😳

Retrofitted 11.2kw Mitsubishi Ecodan to new radiators commissioned November 2021.
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batalto

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15/01/2022 4:56 pm

Mine seems to defrost at roughly the same time every morning, after the showers and it's reheated the tank. Quite cool to see it steaming and then a huge plume of steam. Doesn't seem to take very long but clearly COP impacts. Yesterday we were just under a COP of 3 for all use - so not too bad

12kW Midea ASHP - 8.4kw solar - 29kWh batteries
262m2 house in Hampshire
Current weather compensation: 47@-2 and 31@17
My current performance can be found - HERE
Heat pump calculator spreadsheet - HERE

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JulianC

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Topic starter 29/01/2022 3:50 pm

Unbelievable numbers 😳

My Daikin thinks it’s used 2198kWh (actually it’s 2915kwh) and produced heating of 9102kWh

This gives a SCOP of 3.12. 👍 I’m pleased.

And this against an MSC predicted energy use of 4766kWh.

I can only roughly estimate the cost of this because I don’t know how much my solar PV has contributed and I don’t know the split between day and night tariffs.

Daikin Altherma 3H HT 12kWh ASHP with Mixergy h/w cylinder; 4kW solar PV with Solic 200 electric diverter; Honda e and Volvo EX30 Ultra Twin Performance electric vehicles with Myenergi Zappi mk1 & Ohme chargers

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batalto

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29/01/2022 6:28 pm

@julianc over what period?

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JulianC

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Topic starter 29/01/2022 10:47 pm

@batalto you have to go back to the beginning of my post 😊. Since April 22, 2021

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batalto

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30/01/2022 11:54 am

@julianc pretty good. Not too far from my own numbers. To the end of December we had used 3MW. I'll be really interested to see the total intensity, but the mild December might be hiding things, so I'll be taking with a pinch of salt

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JulianC

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Topic starter 02/03/2022 10:29 pm

We’ve used 550kWh in February or 19.6kWh/ day compared to a predicted 45.1kWh/day.

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Mars

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03/03/2022 1:37 pm

@julianc, that's very, very good. What's your target temperature across the property?

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JulianC

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Topic starter 03/03/2022 3:20 pm

So radiator water temp out is set at 54C. We heat home to 18.5C in the mornings rising to 20C at 5pm and 20.5C at 7:30pm. Set back to 10C at either 10:30 week nights or 11:30pm Friday and Saturday night (dirty stop outs that we are 😂)

Hot water temp is also 54C but think I will step both down a degree and see how we do

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JulianC

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Topic starter 11/03/2022 6:12 pm

£112 electric spend for February. This is my full electric usage including ASHP, cooking, home and two EVs.
Based on the Daikin data, I have a SCOP of 3.28. Which seems ok. And I’m at 58% of the electric consumption estimated by MCS model. So very happy

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JulianC

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Topic starter 15/04/2022 7:48 pm

£159 bill for March. 480kWh. New Octopus prices impacted the bill.
ASHP has used 4211kWh to date (1 week off a year). 14050kWh of heat gives SCOP 3.34. Predicted from MCS 7088kWh or 59.4%

So everyone energy rates have gone up. At my new rate, my annual electric charge would be £1179 for heating and hot water. So similar to current oil costs would cost me £1384 for 1500L of oil. Still saving.
We generated 21.3kWh of solar PV today that heated water and charged an EV (a bit). Based on the FiT this pays for all my electric costs = break even. I’m very lucky here.
I went to the formal opening of Ecobubl, the people who installed my Daikin, on Friday 8th, meet an eco geek hero in the process.

Happy Easter everyone

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Adam C

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17/04/2022 5:26 am

Hi Julian,

You got the meet the man! Sadly I only saw him at a distance at FC Live last year.

Quick question. Where are you getting your data for your Daikin SCOP numbers? I can see on my Altherma 3 some basic numbers but very hard to see a accurate SCOP. Have you managed to extract the data somehow from the Daikin unit or are you doing by another means?

Thanks.

Adam

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