Air Source heat Pump

[akaPABLO01]

So what would recommend for new build 170 s/m Bungalow , ? , how many meters of pipe do you need to put in the ground ?, would you put any solar panels on the roof ?

You’re probably looking at a 14kW unit heat pump. Depending on bathrooms and bed with en-suite maybe 270-300 litre cylinder. Ashp would work well, hp, cyl, 5 standard rad upgrade and install with rhi application £12,500 with up to £10,000 rhi. Yours may only pull in £7,500 at a guess?

Gshp, it depends on your soil type as to what number of slinkies go in the ground. We usually air on caution and use 1WmK. That’d be 6+ slinkies depending on how much heat loss is calculated and hp size to cope. These systems are extremely invasive on install, the digging and plant/pump room. So this install is rather more expensive. You should be seeing £25,000+ for install with a caveat: you do ground work. Return on rhi could see up to £30,000. Your return, maybe £20,000/£25,000 at a guess, depends on your epc.

This only looks at domestic rhi, a more popular approach would be to create district heating systems. To support hot water compliment it with solar thermal and twin coil cylinder. Payments are the made on hp size x 1314 (annual heat required) for tier 1 then tier 2 outside that. There are requirements involved such as shared heat pump(s).

I always recommend solar, get it installed especially new builds.

 

[akaPABLO01]

Nope, no backup required, pipes 4-5 ft underground so never reach - 20 down there, good installation in the house is critical tho if at those temps, we've got as low as - 8 for a few days and the house would drop 2 degrees over the day, that was with the heating only running at night, I would imagine if it had got any colder it would have had to run a bit during the day to top it up too.
I have 600m of pipe in the ground for a 250sqm house, would have got away with 500 but had the space

That isn’t enough pipe in the ground. What was you soil type ground conductivity /K?

 

[Pond digger]

So how much better is ground source over air?

I wonder if air source could be improved by pulling air through a mini poly tunnel when the sun’s out, and through an underground pipe at night? Perhaps there’s a graph that shows the effect of different air temps on running costs?

 

[Exfarmer]

The biggest problem with ASHP is the humidity of the air, which will condense on the vanes it is passing through.
If the air is dry as it will be below zero air temperature this condensation will not occur and performance can be quite efficient.
The problem though is in the air temperature range zero to 12 degrees, above this the condensation will just drain away and no problems are created.
However , in this mid range, which is typical temperatures in the period from October - April , the condensation will freeze on the vanes due to the circulating fridge gas being below zero. This ice has to be removed by running the system in reverse and the closer the outside air is to zero and the higher the humidity , the more this will occur, till it is running in reverse nearly as often as forward and effective heat production stops.
So it is not as simple as asking the question at what temperature do they become inefficient, with the right gas, I am sure you could run them at the south pole, with the wrong humidity they are a money pit.
Sadly my experience in Suffolk is they are great in Summer but horrendously expensive in winter
Prewarming the air by passing through polytunnel etc will certainly help,
there were grainstore roofs double skinned utilising the sun to pre warm air for grain drying

 

[Mur Huwcun]

So with GSHP will you need a boiler to have the house nice and warm as well to heat the water for the under floor heating if it gets down to -20 ?

Not on a new build, never. We have underfloor heating throughout the house here, half the house is original stone built and other half is 2017 new built. The floor in the new part never feels as warm as the old part as that room just does not need the heat. I would think a GSHP in a new max insulated house to be ideal. We.re on about £100 a month electricity use averaged over twelve months now for everything including the heat pump. It used considerably more in first few months which was worrying but has really settled now after second winter albeit its been a mild one. If you have the correct soil I would recommend to anyone especially as you have your own digger etc. We dug out trenches in a morning with a 13tonner and then backfilled them the next day and reinstated everything by the end of the day. Still haven’t properly reseeded the field but that’s a different story!!

 

[Speedstar]

Not on a new build, never. We have underfloor heating throughout the house here, half the house is original stone built and other half is 2017 new built. The floor in the new part never feels as warm as the old part as that room just does not need the heat. I would think a GSHP in a new max insulated house to be ideal. We.re on about £100 a month electricity use averaged over twelve months now for everything including the heat pump. It used considerably more in first few months which was worrying but has really settled now after second winter albeit its been a mild one. If you have the correct soil I would recommend to anyone especially as you have your own digger etc. We dug out trenches in a morning with a 13tonner and then backfilled them the next day and reinstated everything by the end of the day. Still haven’t properly reseeded the field but that’s a different story!!

Would it be it be better to dig the pipe in deeper than 1 meter would it work better at 2 meters ?

 

[Mur Huwcun]

Would it be it be better to dig the pipe in deeper than 1 meter would it work better at 2 meters ?

Apparently no, 1.2 is the norm plus anything over and you need shuttering to support the trenches .

We went down 6 or 7 feet in some places to try and keep the trench bottom fairly flat and avoid low spots in the run

 

[Speedstar]

Apparently no, 1.2 is the norm plus anything over and you need shuttering to support the trenches .

We went down 6 or 7 feet in some places to try and keep the trench bottom fairly flat and avoid low spots in the run

View attachment 800118

I thought you put the pipe in ,on a loop system ? Or can you do any way ?

 

[24/7 farming]

That isn’t enough pipe in the ground. What was you soil type ground conductivity /K?

Holy crap how much would i need!?, that covers near quarter an acre, pipes r in mostly a clay over sand kind of ground, not got figures to hand for calcs, but all was worked out at the time.

3yrs ago since installed and not run short of heat yet in a conventional cavity (200mm wide) block built house. heating and water cost is averaging 550€ last two years.

Single phase 12kv pump running most of time on night rate electricity except for heating water as required during day

 

[Exfarmer]

Holy crap how much would i need!?, that covers near quarter an acre, pipes r in mostly a clay over sand kind of ground, not got figures to hand for calcs, but all was worked out at the time.

3yrs ago since installed and not run short of heat yet in a conventional cavity (200mm wide) block built house. heating and water cost is averaging 550€ last two years.

Single phase 12kv pump running most of time on night rate electricity except for heating water as required during day

12 Kw pump takes some power, how much is that costing a year?

 

[24/7 farming]

12 Kw pump takes some power, how much is that costing a year?

That's its max, 40-50‰ all I ever seen it run at, thank god, cos it was run up to max after install and sounded like a small aircraft! Has soft starts and stops n all that jazz too. I did hav to get a heavier (16kw?) supply, I remember I had to tick the same box as for running a milking parlour! [emoji23]
Runs average 8 hours a day winter and less that one for summer just to heat water

 

[24/7 farming]

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[MrCatfire]

The first thing to consider getting a ashp or gshp is the fact is your house been designed or correctly upgraded on insulation? Any sales rep will tell you you can retrofit, fact is you can't unless you really spend thousands of pounds upgrounding your house.

 

[akaPABLO01]

The first thing to consider getting a ashp or gshp is the fact is your house been designed or correctly upgraded on insulation? Any sales rep will tell you you can retrofit, fact is you can't unless you really spend thousands of pounds upgrounding your house.

You’re a joker.

I’ve installed a farm house built 1700’s. Works fine with correct amount of loft installation. And if you have drafts then plug them.

 

[MrCatfire]

Just shows how little you know about ashp or gshp, that sentence if you have drafts just plug them says everything, you wally!

 

[akaPABLO01]

Just shows how little you know about ashp or gshp, that sentence if you have drafts just plug them says everything, you wally!

Calm down son. Why wouldn’t someone who is about to spend £10k not have a maintained home? You paint a picture of someone living in a cave if it’s not new build. Just means bigger pump and emitters treacle.

 

[jack6480]

I had the idea whilst pushing muck up the other day, why can’t a gshp be used in a muck pile??

 

[Home Farm]

We live in a rural area and recently installed an 18kW air source heat pump to switch from an oil boiler.


People have a lot of questions, so you can read about our system overview here: http://myhomefarm.co.uk/moving-from-oil-to-air-source-central-heatingor watch our overview video on YouTube:

We are now working on a video to see if our air source heat pump is efficient and whether it was worth the upgrade, which should be interesting. If you have any questions about pumps that we we will provide real life, honest answers.

 

[Home Farm]

A lot of the points raised above are spot on. A well insulated house is key to the efficiency of ASHPs. If your house leaks heat, ASHPs, from our initial experience, will not be effective.

 

[Mr Mackay]

I had the idea whilst pushing muck up the other day, why can’t a gshp be used in a muck pile??

Its just finding an really good way of siting the pipework in , or under the muck ,without wrecking it all afterwards, when the mucks done its heating ?
Probably a few people have tried it