ASHP acoustic cover

[SteamyTea]

7 hours ago, joe90 said:

it was @SteamyTea that pointed out the COP figure drops in relation to relative humidity rather than temperature

Almost.  High humidity can cause frosting up of the units, but they are designed to cope with this.

The efficiency drop in cold weather is more to do with the higher water temperatures people want, rather than the lower amount of energy 'in the air'.  You get a quirk where the efficiency can seem to go very low if you calculate using the celsius or  fahrenheit scale, but that, magically, vanishes when you change to the kelvin scale.

 

24 minutes ago, Dave Jones said:

"My house is 10000m2 and only costs £1 a day and its never on for more than 1 minute etc etc "

WOW, you must have spent hours designing your gas system to be that good.

Oh, hang on a second, you made that up.

[dpmiller]

1 hour ago, Dave Jones said:

 

looking at the rep[ies, what did i tell you at the fanboys. "My house is 10000m2 and only costs £1 a day and its never on for more than 1 minute etc etc "

 

You'll only ever hear one side of heat pumps on here, have a good read up on the other side.

 

Boring.

[dpmiller]

1 hour ago, Dave Jones said:

 

looking at the rep[ies, what did i tell you at the fanboys. "My house is 10000m2 and only costs £1 a day and its never on for more than 1 minute etc etc "

 

You'll only ever hear one side of heat pumps on here, have a good read up on the other side.

 

Really Boring.

Edited July 30, 2021 by dpmiller

[PeterW]

1 hour ago, Dave Jones said:

 

looking at the rep[ies, what did i tell you at the fanboys. "My house is 10000m2 and only costs £1 a day and its never on for more than 1 minute etc etc "

 

You'll only ever hear one side of heat pumps on here, have a good read up on the other side.

No-one has said anything of the sort ..!! All the responses above give facts, house sizes and run costs. 
 

How about you quote the facts on your experience and it becomes more balanced ..??

 

@Moonshine ASHP isn’t for every scenario especially where there are high heat loads due to poor insulation etc. A lot of social housing had them fitted where previously they had storage heaters and the tenants saw significant increases in costs as they went from using electricity off peak to peak for heating when the ASHP was used during the day as a standard heating system with rads. It is most ideally suited to UFH as you can create a thermal store type load using the floor slab overnight (huge storage heater in effect) but rads do work. 
 

You get a lot of emotive type statements around the technology (look at this article for example https://utilityweek.co.uk/concerns-raised-over-headlong-rush-to-air-source-heat-pumps/) where if you read the first few paragraphs you find it’s not entirely true :

 

“They have high maintenance costs; they have a lot of moving parts that can go wrong; they are external; they make a lot of noise,”

 

OK - so, they aren’t high maintenance as there is very little to maintain. Cleaning the coils takes 5 minutes with an air line and that’s about it. Unlike a fuel boiler there are no combustion products to deal with so nothing to corrode. 
 

They have around the same or less number of moving parts to a gas boiler - modern gas boilers are complex beasts and have a lot of parts that are constantly high temperature cycled that causes fatigue. 
 

They are external is an odd statement and not sure why it’s a problem …!

 

And they make “a lot” of noise…. A WB 30i Combi has a sound rating of 50dB, the Mitsubishi Ecodan 8.5kW has a sound power rating of 58dB and a sound pressure of 45dB at 1m…. 
 

There are a lot of badly installed heat pumps that do cause issues and it is this that causes most of the problems. Just by siting a heat pump at 90 degrees to a wall for example rather than facing a neighbours wall in a narrow gap between two houses can substantially reduce noise and there are other basic install issues that cause problems further down the line such as not using flexible hoses or under sizing the units that will create a lot noiser installation both internally and externally. 

 

 

[JamesP]

Having lived with an Ecodan for over a year now it has used just over 4000 kWh for both DHW and heating.

This is for a very well insulated, air tight home with 5 adults.

Never run out of hot water and the noise this particular unit makes is not an issue. It is sited outside next to the wall of the house. 

I originally planned for it to be sited 15 metres away but the suppliers said its not necessary.

However in built up areas and in poorly insulated properties the results might be very different.

And yes the RHI did influence the decision to proceed with an ASHP.

 

Edited July 30, 2021 by JamesP

[Tony K]

@PeterW and @SteamyTea thanks for the detailed advice. My SB will be well insulated, have UFH and good (though not passive standard) air tightness. My research prior to commencement led me to conclude that an ASHP would be a good fit, and I though I remain of that view I can see from your replies that there is a level of detail beyond my understanding which may be critical to the success of the system.

 

Would you expect most good suppliers / installers to apply the level of attention to detail you describe, or is there merit in appointing someone to oversee the optimum configuration of the system? 

 

@Dave Jones you plainly feel differently to many others on this subject, but I've no reason to think you aren't saying it as you see it and trying to give me best advice, so thanks. 

[joe90]

18 minutes ago, Tony K said:

there is a level of detail beyond my understanding which may be critical to the success of the system.

What detail are you talking about? Despite being a retired small time builder I learnt soo much from members here that allowed me to design and instal my own so not rocket science. I really enjoyed the learning curve as well, ask away sunshine!

[SteamyTea]

5 hours ago, Tony K said:

Would you expect most good suppliers / installers to apply the level of attention to detail you describe

Good suppliers/installers yes.

I would expect them to spend several hours on doing a detailed heat loss analysis, which would include daily weather data from your nearest Met Office station.

You can do a lot of the calculations yourself, they are dull and boring to do, but not actually that difficult.  The MCS site used to have the methodology, that every installer was meant to apply, on it.  It is pretty good.

 

Regarding your UFH, how much insulation, and what type, are you fitting under it?

[Tony K]

50 minutes ago, SteamyTea said:

Good suppliers/installers yes.

I would expect them to spend several hours on doing a detailed heat loss analysis, which would include daily weather data from your nearest Met Office station.

You can do a lot of the calculations yourself, they are dull and boring to do, but not actually that difficult.  The MCS site used to have the methodology, that every installer was meant to apply, on it.  It is pretty good.

 

Regarding your UFH, how much insulation, and what type, are you fitting under it?

 

The slices of the cake go:

 

Ceramic tiles. 

Screed with UFH inside. 65mm.

PIR insulation 90mm

RC slab. 

[Tony K]

6 hours ago, joe90 said:

 really enjoyed the learning curve as well, ask away sunshine!

 

You might regret that act of kindness @joe90! 

[Temp]

Some reading...

 

Noise survey on 9 ASHP systems..

 

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/48204/3307-acoustic-noise-air-source-heat-pumps-1.pdf

 

Page 24 suggests some ASHP were 5db louder than the makers spec. Out of 9 sites only one was quieter than the makers spec.

 

On page 27 they calculate how far away you have to be (eg from neighbours) before the noise level fell below the limit for Permitted Development Rights (eg <42db). It ranged from 4 to 28 meters. More if they make "tonal" noise. In one case 45m.

 

The majority  of  the units  require a separation  distance  of  between 10 and  20m, which limits  their  potential  use  on  flatted developments.

 

 

 

 

[Dave Jones]

5 hours ago, Temp said:

Some reading...

 

Noise survey on 9 ASHP systems..

 

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/48204/3307-acoustic-noise-air-source-heat-pumps-1.pdf

 

Page 24 suggests some ASHP were 5db louder than the makers spec. Out of 9 sites only one was quieter than the makers spec.

 

On page 27 they calculate how far away you have to be (eg from neighbours) before the noise level fell below the limit for Permitted Development Rights (eg <42db). It ranged from 4 to 28 meters. More if they make "tonal" noise. In one case 45m.

 

 

 

 

 

 

 

 

Heresy! You are preaching to the converted here ......

[SteamyTea]

6 hours ago, Tony K said:

PIR insulation 90mm

Can you double that thickness?

[Moonshine]

6 hours ago, Temp said:

Some reading...

 

Noise survey on 9 ASHP systems..

 

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/48204/3307-acoustic-noise-air-source-heat-pumps-1.pdf

 

Page 24 suggests some ASHP were 5db louder than the makers spec. Out of 9 sites only one was quieter than the makers spec.

 

On page 27 they calculate how far away you have to be (eg from neighbours) before the noise level fell below the limit for Permitted Development Rights (eg <42db). It ranged from 4 to 28 meters. More if they make "tonal" noise. In one case 45m.

 

Interesting study, and I'll have a read through (only skimmed it for now), especially how the measurements correlate to the siting of the unit.

One point to note is 4 out of the nine were as per the manufacturers published data.

A flaw in the assessment of tonality is they have measured how tonal it is at one metre from the unit and assumed it will have the same tonality at a receptor some distance away. This does not happen in real life as the tonal elements reduce in  level at a distance, and are more easily masked by the ambient noise level at the receptor.

A key key point of how you assess acoustic characteristics of sound is what those charateriestics are at the receptor not the source (see BS4142:2014-A.1:2019).

So that 45m distance stated is flawed.

 

[PeterW]

7 hours ago, Temp said:

 

Page 24 suggests some ASHP were 5db louder than the makers spec. Out of 9 sites only one was quieter than the makers spec.

That document is 10 years old - yes they were noisier 10 years ago ! They were also less efficient and more likely to be non inverter drive. 
 

Worth having a quick look though this (other brands are available ..!) https://ultraquietecodan.co.uk

 

[PeterW]

8 hours ago, Tony K said:

 

The slices of the cake go:

 

Ceramic tiles. 

Screed with UFH inside. 65mm.

PIR insulation 90mm

RC slab. 

Not enough insulation under there for UFH and possibly borderline on building regs depending on the P/A ratio. 

[joe90]

My UFH insulation is 200mm ?

[A_L]

On 28/07/2021 at 23:14, Tony K said:

My own SB is small (100m2 single storey)

 

At 7m x 14m it will have a U-value of 0.17W/m² .K. Well below the maximum allowed by Part L1A (0.25, Table 2) but significantly more than the value used to calculate the TER for CO₂ emissions 0.13W/m² .K (Table 4) and you would have to upgrade elsewhere to compensate at probably poorer return.

 

150mm would give U = 0.12 W/m² .K 

[Tony K]

3 hours ago, PeterW said:

Not enough insulation under there for UFH and possibly borderline on building regs depending on the P/A ratio. 

 

It's approved by building regs already (full plans approved). Why would that be insufficient for UFH? 

 

2 hours ago, A_L said:

 

At 7m x 14m it will have a U-value of 0.17W/m² .K. Well below the maximum allowed by Part L1A (0.25, Table 2) but significantly more than the value used to calculate the TER for CO₂ emissions 0.13W/m² .K (Table 4) and you would have to upgrade elsewhere to compensate at probably poorer return.

 

150mm would give U = 0.12 W/m² .K 

 

It's an L shape, 5m wide if that makes a difference? 

[A_L]

54 minutes ago, Tony K said:

It's an L shape, 5m wide if that makes a difference? 

 

Not much, a symmetric 'L' is about 0.18W/m² .K

[puntloos]

Have we collectively figured out what the quietest ASHP is (both external AND internal?) - @zoothorn had a bit of a nightmare but the topic to me sounded more like the cylinder and connected pumps were at fault, not the ASHP itself?

 

My preference is indeed 'within regulations' (but if I place my ASHP in the place indicated it's going to be 7m away from the nearest window so even oldcrap jet engine ASHPs might fall below 43dB(regs) at 7m..)

 

Clearly it has to be inverter-based, and ideally new-ish so it can be switched from heating to cooling through the control system not with 'manual dip switches' (which I think is EcoDan's case.. not the end of the world but eh.. still somewhat annoying)

[puntloos]

Just checking in and noting that the Mitshubishi marketing board is perhaps a bit more enthusiastic than Nibe's 

 

Nibe F2020:

 

Ultraquietecodan:

 

[SteamyTea]

4 hours ago, Tony K said:

Why would that be insufficient for UFH

UFH runs at a higher temperature than ambient, and you can treat the ground as an infinite heat sink, with a mean heating season temperature of about 8°C.

You also have a lot of floor area.

Remember that U-Value is W/m²K, so a lot of area at a higher temperature means greater power going though it.

So imagine a wall of 10 m² and an inside air temperature of 20°C and an outside air temperature of 2°C, if the U-Value is 0.15 W/m²K, the losses will be 27W.

Now imagine a 10m² bit of floor, that is at 30°C and the ground is at 8°, with the same U-Value, the losses will be 33W.

[Gone West]

2 hours ago, puntloos said:

Nibe F2020:

IIRC that's the one my neighbours had and I couldn't hear it behind a 2m high solid fence and it was 2m the other side of the fence.

[puntloos]

38 minutes ago, Gone West said:

IIRC that's the one my neighbours had and I couldn't hear it behind a 2m high solid fence and it was 2m the other side of the fence.

I also hear good things on Nibe's control system.. but.. it uses R410A rather than R32 so the carbon footprint is pretty large. For now I suppose it might be my frontrunner but the ecodan is a close second. 

 

But then I found the Daikin - seems to be the best of most worlds. R32. Quietest. Just... 10m max pipe.. (to be fair this is the only brand even mentioning pipe length)

 

Given that I (plan to) have 3 phase I figured it would have benefits to use it for the ASHP.. but as far as I can tell the COP of the single-phase is actually better. Why would you ever want the 3phase one?

 

@pocster - from your evil eye image, it looks like you have this one. Do you know if it's easy to reverse cooling? Any downsides I should be aware of? How quiet are the indoor/outdoor parts day to day? Hot water is limited to 35C?

 

Edited July 31, 2021 by puntloos