Where best to site ASHP

[Chanmenie]

Hi

 

Can the ASHP experts please give me some guidance.

where would you suggest is the best place to site the ASHP, giving consideration to the neighbours 

but taking advantage of sunlight ( I assume using air warmed by the sun can be beneficial).

The boundary to the left is a 2.2m high leylandii hedge, so I would assume that would absorb some of the noise, the wall is approx 4m from the neighbours wall. 

 

did not want to site it in the rectangle area between lounge and kitchen as that’s going to be patio.

 

Also depending on where the best place is to site, how is it best to run the pipe work, construction will be insulated raft and Isotex ICF.

can I run the pipes through the raft / slab  in the EPS or should they go underneath the raft 

 

Thanks 

Mark

 

[SteamyTea]

There is no real advantage site an ASHP in sunlight, they are not solar panels.  They use the air, which does not change much in temperature, especially when it is drawn in by the fan.

 

[Chanmenie]

Yeah I get they are not solar panels, but I read somewhere that siting south facing was beneficial.

 

[dpmiller]

Slight benefit in defrosting perhaps.

[joe90]

1 hour ago, Chanmenie said:

I assume using air warmed by the sun can be beneficial)

I made that assumption, citing running one in the daytime (warmer air) against running at nighttime (E7) but was told it makes very little difference. ?‍♂️

[Chanmenie]

That’s handy to know, so no.loss of benefit if I face it down the garden away from the neighbours either side

[gramos]

, You have probably sited this by now , but ... would it be a good idea to place it  "downwind " , away from the house ?

This because of the noise they  can generate , as if it were sited upwind the noise would carry toward the house ?

 I  know thhis is apparent in siting of generators .

[Marvin]

If you use it for cooling in the summer then perhaps better out of the sun?

[SteamyTea]

9 minutes ago, Marvin said:

If you use it for cooling in the summer then perhaps better out of the sun?

The sun does not change the air temperature much.

You feel hot in the sun because you have 1100 W/m² of radiation hitting you.

[Marvin]

9 minutes ago, SteamyTea said:

The sun does not change the air temperature much.

You feel hot in the sun because you have 1100 W/m² of radiation hitting you.

Maybe, but on the EPDM flat roof on the south side of the bungalow there's definetly warmer air hitting me.

[SteamyTea]

15 minutes ago, Marvin said:

Maybe, but on the EPDM flat roof on the south side of the bungalow there's definetly warmer air hitting me.

Now get a large fan to blow that air away.

[Marvin]

I have no fans. Even my wife is not impressed.

[ReedRichards]

Where do the pipes from the heat pump need to get to?  Can you move the window that is partially obscured by the TV set (?) a little towards Oakcroft and put it the other side of that wall?

[ProDave]

Right at the front of the side wall would be my choice, i.e. facing about south west.

 

I think sun does make a difference, certainly here, when we get a cold spell the north side of the house becomes a permafrost in winter but the south side is definitely very much warmer, so probably less defrosting issues.

 

And although it may seem controversial to put it almost in the front garden (actually the side garden I am proposing)  people tend not to spend time in their front gardens so it keeps any noise away from yours and your neighbours back gardens.

[joth]

11 hours ago, ProDave said:

And although it may seem controversial to put it almost in the front garden (actually the side garden I am proposing)  people tend not to spend time in their front gardens so it keeps any noise away from yours and your neighbours back gardens.

This is a really good point. Front of the house also has road noise so putting the heat pump out front helps mask one with the other. 

I think it's only controversial because it's uncommon. Cycling around rural villages I see plenty of ugly oil and LPG tanks sat out the front of cute looking cottages. And ugly TV masts, satellite dishes and telegraph wires/poles.

It's just a matter of time for heat pumps to become common enough that people don't notice them so readily

 

 

[ReedRichards]

When people come to the house they would either say "Wow, an air conditioning unit" or "Ew, an ugly air conditioning unit" (I assume most people would not recognise an ASHP for what it   is).   If @jothis still finding big tanks ugly then it must surely be some decades before ASHPs fade from notice.

[SteamyTea]

5 minutes ago, joth said:

Front of the house also has road noise so putting the heat pump out front helps mask one with the other.

I have often thought that, and a lot of houses have the 'master bedroom' towards the back.

Though if the installation is properly designed, noise will not be a problem.

 

12 hours ago, ProDave said:

I think sun does make a difference, certainly here, when we get a cold spell the north side of the house becomes a permafrost

That is because there is no solar radiation hitting the frost, not because the air is cooler. 

 

I am not sure how ASHPs would be affected if they were exposed to regular high winds.  Apart from weathering, if the fan is working against the prevailing wind direction, that may impact performance.  Not sure if anyone has looked into this.  Probably a marginal difference as generally the strong winds are from the SW, and they are warm winds.

[joe90]

12 hours ago, ProDave said:

I think sun does make a difference, certainly here, when we get a cold spell the north side of the house becomes a permafrost in winter but the south side is definitely very much warmer, so probably less defrosting issues.

I tend to agree, mine is on the west side of the house so gets no sun in the morning when it’s been frosty and I am sure if it was on the east side the morning sun may help stop defrosting early in the morning as the sun would warm the metal a little.

[joe90]

11 minutes ago, SteamyTea said:

That is because there is no solar radiation hitting the frost, not because the air is cooler. 

But if the metal of the ASHP gets solar radiation surely the frost 0has less chance. My car is usually parked in the shade first thing in the morning and when frosty it lasts fir hours. I had to use the car early one morning so the previous night I moved it out of the shade of the house and by the time I left it was fully defrosted.

Edited January 24, 2022 by joe90

[TonyT]

12 hours ago, ProDave said:

Right at the front of the side wall would be my choice, i.e. facing about south west.

 

I think sun does make a difference, certainly here, when we get a cold spell the north side of the house becomes a permafrost in winter but the south side is definitely very much warmer, so probably less defrosting issues.

 

And although it may seem controversial to put it almost in the front garden (actually the side garden I am proposing)  people tend not to spend time in their front gardens so it keeps any noise away from yours and your neighbours back gardens.

That’s my plan, front garden consists of a driveway for 2 cars, 4 wheelie bin area plus space then steps/path  up to the house approx 3 metres height distance.

 

 

[SteamyTea]

29 minutes ago, joe90 said:

But if the metal of the ASHP gets solar radiation surely the frost 0has less chance. My car is usually parked in the shade first thing in the morning and when frosty it lasts fir hours. I had to use the car early one morning so the previous night I moved it out of the shade of the house and by the time I left it was fully defrosted.

The case of an ASHP has a mass of a few kilograms, and steel has a relatively low SHC,  around half that of air. (mild steel 0.51 kJ.kg^-1.K^-1)

It is also not the frost on the unit that needs defrosting, it is the moisture in the air that condenses and then fuses to the heat exchanger.

If you want to store energy in metal, try Beryllium, it has a SHC of 1.8  kJ.kg^-1.K^-1, less than half that of water.

There is a reason that ASHPs are not put in conservatories and lofts, they would suck all the energy out in a few minutes.

 

If you think about it, UFH delivers at about 20 W.m^-2, even a very dull day has solar power at >100 W.m^-2, it is why PV, even at only 20% efficiency, is so effective. 

[epsilonGreedy]

41 minutes ago, SteamyTea said:

even a very dull day has solar power at >100 W.m^-2, it is why PV, even at only 20% efficiency, is so effective. 

 

 

Surely this confirms what people observe, namely the ground on the sunny side of a building can be frost free when the shaded north side suffers a multi day permafrost at this time of year.

[epsilonGreedy]

59 minutes ago, SteamyTea said:

The case of an ASHP has a mass of a few kilograms, and steel has a relatively low SHC,  around half that of air. (mild steel 0.51 kJ.kg^-1.K^-1)

It is also not the frost on the unit that needs defrosting, it is the moisture in the air that condenses and then fuses to the heat exchanger.

 

 

A low heat capacity, high thermal conductivity metal case sounds like the perfect design to create a solar powered defrosting unit. As the case warms up it will radiate half its heat inside the case thus creating a micro climate to defrost the inner works of the ASHP.

 

I have long felt the claim that ASHP position is not affected by direct radiant heat from the sun to be dubious. One of a few established forum beliefs that needs to be challenged.

[Marvin]

4 hours ago, ReedRichards said:

When people come to the house they would either say "Wow, an air conditioning unit" or "Ew, an ugly air conditioning unit" (I assume most people would not recognise an ASHP for what it   is).   If @jothis still finding big tanks ugly then it must surely be some decades before ASHPs fade from notice.

Most people around here think its an air conditioning unit.

[joe90]

2 minutes ago, Marvin said:

Most people around here think its an air conditioning unit.

Not surprising as they look exactly the same!