Heat loss from pump to storage cylinder

[paulc313]

Afternoon Everyone,

 

We are going to purchase a ASHP for our self build. I have reservations about the noise from the pumps ( I work in Environmental Health and deal with noise complaint from them). Also my mum and dad just visited, staying in an Airbnb which had one and the you could hear it ticking over during the night which would really annoy me. I think I've found an alternative position that would make it inaudible but it is 25 metres away next to my father in laws workshop. We will be running a cable anyway from the workshop as were putting PV on the workshops roof to top up the hot water. I just wondered what the heat loss will be like with a 25 metre pipe that's well insulated, could anyone calculate this or know what it would be?

 

Thanks

 

Paul 

[Dreadnaught]

This was the pipe that was recommended for me to use in a similar situation. My ASHP will be about 15m from my plant room.

 

It is pricey at £50+ per metre. And it is big and fat too (125mm outer diameter) so, if it needs to turn vertical to enter you dwelling, it will need to be buried deep to obtain the radius bend (perhaps 800mm+).

 

http://www.buffertanks.co.uk/shop/microflex-duo-underground-insulated-pipe-kit-2m-32mm-outer

 

 

 

Edited August 3, 2020 by Dreadnaught

[ProDave]

Are you over thinking this?  What sort of noise issues have you really seen?

 

The main consideration, is with an ASHP all the noise is made by the outside unit.  So just position it where it will be least obtrusive?  Ours is at the end of the house behind the garage.  Even with the nearby bedroom window open you can't hear it, because it's round the corner and not very loud to start with.

 

Why do people perceive an ASHP as "noisy" yet are prepared to put up with an oil fired boiler with a burner roaring inside the house which is much more invasive?

 

I suspect some of the complaints you might have dealt with were perhaps old large units that don't have inverter drive?  they can start up with quite a clonk,. and only run at full speed or off.  A modern inverter driven ASHP will spend a lot of it's time just running gently not making much noise at all.

 

The biggest source of noise nuisance from ours, is the water circulating pump (that you have with any heating system)  that is the only thing you can hear inside the house but even so it annoys me so I just set the times so the heating is not on at night for a silent nights sleep.

[Russell griffiths]

I would agree with Dave your thinking of an ashp outside a poorly built double glazed (badly fitted) house, if you build your house correctly and make it nice and airtight and install stuff well it will not be a problem. 

 

My house is only half built and its silent inside, as you walk in the quite just hits you. 

I don’t think you need to worry. 

[Dan F]

27 minutes ago, Dreadnaught said:

This was the pipe that was recommended for me to use in a similar situation. My ASHP will be about 15m from my plant room.

 

It is pricey at £50+ per metre. And it is big and fat too (125mm outer diameter) so, if it needs to turn vertical to enter you dwelling, it will need to be buried deep to obtain the radius bend (perhaps 800mm+).

 

http://www.buffertanks.co.uk/shop/microflex-duo-underground-insulated-pipe-kit-2m-32mm-outer

 

 

 

 

I paid £22/m2 for Rauthermex 25+25/111mm DUO Pipe.  We are using it for ASHP flow/return, and put it under slab to avoid penetrations in wall and also because our plant room doesn't have an external wall.

 

Edited August 3, 2020 by Dan F

[Dan F]

 

(Page 17 of RAUTHERMEX manual)

[paulc313]

On 03/08/2020 at 16:54, ProDave said:

Are you over thinking this?  What sort of noise issues have you really seen?

 

The main consideration, is with an ASHP all the noise is made by the outside unit.  So just position it where it will be least obtrusive?  Ours is at the end of the house behind the garage.  Even with the nearby bedroom window open you can't hear it, because it's round the corner and not very loud to start with.

 

Why do people perceive an ASHP as "noisy" yet are prepared to put up with an oil fired boiler with a burner roaring inside the house which is much more invasive?

 

I suspect some of the complaints you might have dealt with were perhaps old large units that don't have inverter drive?  they can start up with quite a clonk,. and only run at full speed or off.  A modern inverter driven ASHP will spend a lot of it's time just running gently not making much noise at all.

 

The biggest source of noise nuisance from ours, is the water circulating pump (that you have with any heating system)  that is the only thing you can hear inside the house but even so it annoys me so I just set the times so the heating is not on at night for a silent nights sleep.

@ProDave Not overthinking this, it is a real and genuine problem. The airbnb my mum and dad have just lived in was built in 2016 with the ASHP sitting around 2 metres away from the ground floor windows and around 3-5metres from the 1st floor bedroom windows. You could hear it ticking over during the night with the windows closed. It wasn't loud but just an annoying noise when your trying to get to sleep. Re your point about the noise from oil fired boiler, I wouldn't put up with that either or even a gas boiler's pump. 

[pdf27]

If you want to put it a long way away, consider split units. Some of the Panasonic ones can be up to 50m long on the refrigerant lines, and the energy transfer is as a phase change rather than heat directly so losses should be small. It's more expensive - not a DIY job - but shouldn't be horrific.

[Thedreamer]

I have a mini air exhaust heat pump on our 260 litre hot water tank inside our house.

 

It sits in a cupboard within our utility room, but produces virtually no noise when the doors are shut.

 

Presumably the larger one that are outside for underfloor heating are much louder. 

 

I would think in a self build with triple glazing, airtight, modern heat pump it's not going to be an issue.

[SteamyTea]

If the new ASHP, that is heating a fairly new built house is noisy:

 

It is sized incorrectly

Is an old design ASHP

Is damaged/broken

 

17 minutes ago, Thedreamer said:

I have a mini air exhaust heat pump on our 260 litre hot water tank inside our house.

That would need a lot of unpicking when it comes to energy conservation.

Though the noise may well be acceptable, that is easy to check with a meter.

 

[ProDave]

55 minutes ago, pdf27 said:

If you want to put it a long way away, consider split units. Some of the Panasonic ones can be up to 50m long on the refrigerant lines, and the energy transfer is as a phase change rather than heat directly so losses should be small. It's more expensive - not a DIY job - but shouldn't be horrific.

But that puts the compressor, a large source of the noise, inside the house.

[Nickfromwales]

ASHP manufacturers have sat up and listened to this, and now you can get ‘super silent’ ASHP’s to suit. 
The Daikin split I worked alongside a while back was horrible, and a bit like a washing machine on spin, ?, no ta. Noisy, and vibrations a plenty. 
A well designed, well thought out installation will not be noisy, and you can direct the sound from the fan at a living barrier to absorb any residual noise from it too. 
You can make big mistakes about where to site this, from an acoustic nuisance PoV, so for eg avoid siting it at the end of a path between a wall and a building or you’re creating a natural ‘horn’ which will amplify the sound a lot. 
Put some thought in and you’ll be able to remove any nuisances   

Edited August 6, 2020 by Nickfromwales

[dpmiller]

4 minutes ago, ProDave said:

But that puts the compressor, a large source of the noise, inside the house.

 

sure about that?

[Nickfromwales]

https://les.mitsubishielectric.co.uk/latest-news/ultra-quiet-ecodan-takes-heat-pumps-to-the-next-level

[Nickfromwales]

 

Has a catchy tune so can’t be wrong ??

[Nickfromwales]

4 minutes ago, dpmiller said:

 

sure about that?

Very. Noisy pile of crap that I witnessed. If that was put in my house it would put out just as quickly. 
?

[ProDave]

Like I say you cannot lump all ASHP's together as the same.

 

My monoblock LG ASHP is very quiet and not a nuisance.  But earlier this year I fitted a 12Kw "no name" ASHP that has no inverter so direct online, full power or nothing.  It starts with one hell of a "clonk" and the lights in the house dip, the sort of thing the DNO's hate with the big start up current,. and when it's running it is very audible inside the house not least because of vibration transmitted through the pipes.

 

I also fitted a small ground source heat pump many years ago and that had the compressor unit in the utility room and that was very noisy as well.

 

So a small, inverter driven monoblock ASHP well sited outside and with properly done pipework so no noise transmitted through the pipes is what I would recommend.

[pdf27]

1 hour ago, ProDave said:

But that puts the compressor, a large source of the noise, inside the house.

Spec sheet says otherwise - the internal unit is always 28dB(A), outside units are between 55 and 69 dB depending on size and load. Remember that fridge compressors are essentially inaudible in modern fridges - my fridge makes a weird squeaking noise (fancy expansion valve?) but that's it. A well balanced sealed compressor should be all but inaudible.

 

Edited August 6, 2020 by pdf27

[ProDave]

Not my findings.  Our own fridge I find intrusively noisy, which is why I am not a fan of "kitchen / living" spaces.  I don't want to sit and watch tv in the same room as the fridge thank you.

[SteamyTea]

27 minutes ago, ProDave said:

Not my findings.  Our own fridge I find intrusively noisy, which is why I am not a fan of "kitchen / living" spaces.  I don't want to sit and watch tv in the same room as the fridge thank you.

My fridge is very quiet, and hardly comes on anyway.

Worked it out that it has an average of 5W usage, considering that the motor runs at 120 W, that would only be 1 hour every day.

 

Get a new fridge.

[Nickfromwales]

Not mine either.

I genuinely was shocked at how noisy the internal unit was. That was fitted in a basement and with good reason. There would be no way a customer would have accepted that inside the kitchen, the utility MAYBE....

Mono-block for me every time, and do away with the need for high temp delivery ( eg heat DHW off overnight 5p electric tariff ) and just use the HP for space heating. 

[ProDave]

1 hour ago, SteamyTea said:

My fridge is very quiet, and hardly comes on anyway.

Worked it out that it has an average of 5W usage, considering that the motor runs at 120 W, that would only be 1 hour every day.

 

Get a new fridge.

I wish fridges were sold like hifi, where you could see them in operation in a "listening room"  They are not. the best you get is a static display in a big warehouse.  I don't believe the spec sheet is anything to go by in reality.  It is not until you have bought it and got it home that you find it is noisier than you would like.  What are we supposed to do? Keep sending it back for a different make until you find a quiet one?

[Jenni]

2 hours ago, ProDave said:

I wish fridges were sold like hifi, where you could see them in operation in a "listening room"  They are not. the best you get is a static display in a big warehouse.  I don't believe the spec sheet is anything to go by in reality.  It is not until you have bought it and got it home that you find it is noisier than you would like.  What are we supposed to do? Keep sending it back for a different make until you find a quiet one?

 

At least the spec sheet for fridges/freezers have a decibel rating. I've been looking at ovens, and none of them even mention sound, though I'm aware they can be loud and varied. 

[Thedreamer]

8 hours ago, SteamyTea said:

 

That would need a lot of unpicking when it comes to energy conservation.

Though the noise may well be acceptable, that is easy to check with a meter.

 

 

Hi @SteamyTea can you expand on the energy conservation part?

 

To be honest I was unsure how this set-up would run before I moved in but it's working really well on very little power and seems to be very efficient.

 

I'll need to wait until a full year has passed before I can reflect fully on the installation.

 

[Thedreamer]

4 hours ago, ProDave said:

I wish fridges were sold like hifi, where you could see them in operation in a "listening room"  They are not. the best you get is a static display in a big warehouse.  I don't believe the spec sheet is anything to go by in reality.  It is not until you have bought it and got it home that you find it is noisier than you would like.  What are we supposed to do? Keep sending it back for a different make until you find a quiet one?

 

I appreciate everybody will have a different view on what is acceptable fridge noise, but can you not a get a feel from online reviews?