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Air to Air : Air Source Heating

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BusyBumbleBee
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Air to Air : Air Source Heating

#239299

Postby BusyBumbleBee » July 25th, 2019, 5:29 pm

I installed 2 air source heating systems in my rambling house which has parts that the central heating system doesn't reach and one air to water system to supplement the central heating system which runs on wood. All work on (roughly) 1KWh in = 3 or 4 KWh heat output. So very 'green' and carbon saving and I am very pleased with them.

All of these are capable or 'reverse running' - i.e cooling as well as heating.

For the three or four days a year when we get unbearable heat (like now) This is a real boon - and does not actually cost a lot.

Itsallaguess
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Re: Air to Air : Air Source Heating

#239308

Postby Itsallaguess » July 25th, 2019, 5:42 pm

BusyBumbleBee wrote:
I installed 2 air source heating systems in my rambling house which has parts that the central heating system doesn't reach and one air to water system to supplement the central heating system which runs on wood. All work on (roughly) 1KWh in = 3 or 4 KWh heat output. So very 'green' and carbon saving and I am very pleased with them.


Very interesting BBB - any chance of a couple of links to the pumps and/or systems?

Cheers,

Itsallaguess

tikunetih
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Re: Air to Air : Air Source Heating

#239315

Postby tikunetih » July 25th, 2019, 6:17 pm

Thinking aloud:

Coastal regions, where I spend a fair amount of time, are usually milder in the winter, and so air source heat pumps might work well in such places during winter. But, the salty air takes it toll on a lot of equipment exposed to it...

Anyone here using air source heat pumps in a coastal location with experience to share?

BusyBumbleBee
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Re: Air to Air : Air Source Heating

#239320

Postby BusyBumbleBee » July 25th, 2019, 6:45 pm

Itsallaguess wrote:Very interesting BBB - any chance of a couple of links to the pumps and/or systems? Cheers, Itsallaguess

There are so many links I could provide you with that I almost don't know where to start. So I recommend this page

https://www.hitachi-hvac.co.uk/ranges/r ... nditioning
(there is a mass of info accessible from this page)

Which gives a range of Hitachi systems. They are mass produced and very reliable and can be (must be) installed by an air conditioning company. The actual units are quite cheap but installation costs more : maintenance is a matter of cleaning air filters every so often. Each unit comprises an internal unit and an external unit. Their real beauty is that they circulate the air so your feet are always warm in winter and you can run at a lower room temperature than if using a 'central heating system

A fair price for supply and installation of a 3 to 4 KWh output jobbie is £1200 - £1500 which will heat one or two rooms. They can be plugged into a 13 amp socket as they only use a maximum of 750 - 850 watts but it is better to have a dedicated connection to the ring main so some idiot doesn't just unplug it, they are usually controlled by a 'zapper'

There are many other suppliers - and the Japanese stuff is always good and much quieter in operation than others.

For bigger systems have a look here: https://www.daikin.co.uk/ I have one running a building I lease to a software company (16 employees) - and they love it. But you need a good, possibly 3-phase, supply for the bigger units

Come back to me if you need more answers

with kind regards - BBB

Itsallaguess
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Re: Air to Air : Air Source Heating

#239321

Postby Itsallaguess » July 25th, 2019, 6:47 pm

BusyBumbleBee wrote:
Come back to me if you need more answers


Thanks BBB - I was really only interested to see which specific pumps/systems you've had installed really.

Cheers,

Itsallaguess

BusyBumbleBee
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Re: Air to Air : Air Source Heating

#239322

Postby BusyBumbleBee » July 25th, 2019, 6:52 pm

tikunetih wrote:Thinking aloud: ... Coastal regions, where I spend a fair amount of time, are usually milder in the winter, and so air source heat pumps might work well in such places during winter. But, the salty air takes it toll on a lot of equipment exposed to it... Anyone here using air source heat pumps in a coastal location with experience to share?

Talk to the manufacturers - particularly the Japanese cos these are installed all along the North Norfolk Coast. The air to water systems are more expensive and there is more outside that can be vulnerable. They are not made in the same quantity as Air-To-Air
which are more conventionally know as air conditioning units - kind regards - BBB

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Re: Air to Air : Air Source Heating

#239331

Postby Dod101 » July 25th, 2019, 7:13 pm

Just what I need to worry about; air source (or for that matter any other kind of) heating. The current temperature is around 26C.

That is my problem, I worry when the temperature is about 3C. Then I have a woodburner and the problem disappears.

Dod

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Re: Air to Air : Air Source Heating

#239338

Postby todthedog » July 25th, 2019, 8:00 pm

I have had air to air ashp in 3 houses 3 countries where we have lived over the past 20 years.

We have installed Mitsubishi recommend for reliability

Finisterre very high humidity 30km from coast mild damp winters, old farmhouse, switching to wood burner in winter.

Sweden inland southern Sweden winter temps down to -15c in winter wood burner, neighbours used ashp all the year round. 70's house well insulated.

Wales just installed 3.5 kW ashp , small retirement bungalow 3km from coast delighted to be able to use air con powered by solar over the last few weeks. Installed cost £1300. Will probably use oil fired ch in depth of winter we will see!

Easy to use cheap to run.

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Re: Air to Air : Air Source Heating

#244862

Postby jaizan » August 16th, 2019, 6:32 pm

BusyBumbleBee wrote:I installed 2 air source heating systems in my rambling house which has parts that the central heating system doesn't reach and one air to water system to supplement the central heating system which runs on wood. All work on (roughly) 1KWh in = 3 or 4 KWh heat output. So very 'green' and carbon saving and I am very pleased with them.


Generally, electric costs about 3~4x the price of gas per KWh. So if you have mains gas as an alternative, there is unlikely to be any cost advantage with a heat pump.

Also, the efficiency of these air source heat pumps is worse at very low outside temperatures. I read the CoP can get down to about 1.5 in such conditions.

Also, they are only "green" if the electricity happens to be generated in an environmental friendly way, such as wind or nuclear. I suppose we just about have enough wind power for that to be the case in the UK, but maybe not so in backward coal burning countries (e.g. Germany).

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Re: Air to Air : Air Source Heating

#244879

Postby BusyBumbleBee » August 16th, 2019, 7:09 pm

jaizan wrote:Generally, electric costs about 3~4x the price of gas per KWh. So if you have mains gas as an alternative, there is unlikely to be any cost advantage with a heat pump {-- absolutely agreed - but we have no gas here : makes the gov't decision to ban gas in homes seem extremely bizarre--}.

Also, the efficiency of these air source heat pumps is worse at very low outside temperatures. I read the CoP can get down to about 1.5 in such conditions.{-- True - but at more normal temperatures (7 degrees C) they work well. Also remember that temperatures are often quoted at ground level and are higher at the intake level of these machines. You also need a backup system for low temperature conditions and I have 24KW of wood burner capacity available --}

Also, they are only "green" if the electricity happens to be generated in an environmental friendly way {-- simply not true in most cases (particularly for replacing night storage heaters): they save on average about two thirds of the electricity you would have used --}, such as wind or nuclear. I suppose we just about have enough wind power for that to be the case in the UK, but maybe not so in backward coal burning countries (e.g. Germany).


They can be considered "green" if they save electricity that was generated in any way. It's called energy saving which is as important a part of the Green Agenda as generating energy from renewable sources.

Overall I think I have saved more energy than most by using technologies such as this - my electricity bill is lower than it was before I started on the journey and my oil fired boiler has gone so I don't use any oil at all now. As I think I said before I cannot install solar panels for a variety of reasons and I can't install a wind turbine because of bats and the proximity of a television mast so this is the only route I can take. with kind regards - BBB

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Re: Air to Air : Air Source Heating

#244931

Postby jaizan » August 16th, 2019, 11:56 pm

BusyBumbleBee wrote:They can be considered "green" if they save electricity that was generated in any way.


Well obviously air source is greener than a resisitive electric heater, but that is not the best benchmark.

However, if you compare burning gas to heat at 90% efficiency, or burning gas to generate electric at 40% efficiency, then losing some of it in transmission and having a COP of 2.5 averaged over a season, then the net outcome of the both alternatives is similar.
If we compare the air to air with coal generated electric, it is worse than gas central heating.

BusyBumbleBee
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Re: Air to Air : Air Source Heating

#245006

Postby BusyBumbleBee » August 17th, 2019, 12:35 pm

jaizan wrote:Well obviously air source is greener than a resistive electric heater, but that is not the best (-- perfection is the enemy of the good - if we wait for the best then we will wait for ever as the planet destroys itself --} benchmark.

However, if you compare burning gas {-- but I have no gas so while I know all of this it ain't no use to me --} to heat at 90% efficiency, or burning gas to generate electric at 40% efficiency {-- BUT A combined-cycle power plant uses both a gas and a steam turbine together to produce up to 50 percent more electricity from the same fuel than a traditional simple-cycle plant. The waste heat from the gas turbine is routed to the nearby steam turbine, which generates extra power. So it runs at about 62% efficiency better methinks to look at increasing the efficiency here --}, then losing some of it in transmission and having a COP of 2.5 averaged over a season, then the net outcome of the both alternatives is similar.
If we compare the air to air with coal generated electric, it is worse than gas central heating {-- but I have no gas so while I know all of this it ain't no use to me --}.


Of course we could wait for the development of a Carnot engine or pocket sized Nuclear fission plant but what we are trying to do is to use practical solutions to reduce our carbon footprint - solutions that exist today and which can give proven benefits.

What I think we are trying to achieve is net zero but we are where we are, and definitely starting in the wrong place which makes it difficult or impossible to get to our intended destination.

The journey there (to net zero) is rather like this journey:
A genial Irishman, cutting peat in the wilds of Connemara, was once asked by a pedestrian Englishman to direct him on his way to Letterfrack. With the wonted enthusiasm of his race the Irishman flung himself into the problem and, taking the wayfarer to the top of a hill commanding a wide prospect of bogs, lakes, and mountains, proceeded to give him, with more eloquence than precision, a copious account of the route to be taken. He then concluded as follows: ‘Tis the divil’s own country, sorr, to find your way in. But a gintleman with a face like your honour’s can’t miss the road; though, if it was meself that was going to Letterfrack, faith, I wouldn’t start from here.’

kind regards - BBB

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Re: Air to Air : Air Source Heating

#245016

Postby doug2500 » August 17th, 2019, 1:09 pm

Mitsubishi do a couple of coastal protection models which only cost a fraction more than the standard ones.

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Re: Air to Air : Air Source Heating

#245043

Postby dspp » August 17th, 2019, 3:06 pm

jaizan wrote:
BusyBumbleBee wrote:I installed 2 air source heating systems in my rambling house which has parts that the central heating system doesn't reach and one air to water system to supplement the central heating system which runs on wood. All work on (roughly) 1KWh in = 3 or 4 KWh heat output. So very 'green' and carbon saving and I am very pleased with them.


Also, they are only "green" if the electricity happens to be generated in an environmental friendly way, such as wind or nuclear. I suppose we just about have enough wind power for that to be the case in the UK, but maybe not so in backward coal burning countries (e.g. Germany).


In 2018 renewables generated about 40% of Germany's electricity (https://e360.yale.edu/digest/renewables ... -last-week). The UK number for 2018 was about 35% (from memory).

So actually Germany is ahead of the UK in the migration to renewables for electricity, and has been for decades. In both countries the migration is moving quite fast at present which is a good thing. The next big steps will be transportation, and heating/cooling. The heating/cooling fraction will mean a very substantial migration to ASHP just as BBB has done in this case (well done BBB).

regards, dspp

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Re: Air to Air : Air Source Heating

#245152

Postby jaizan » August 18th, 2019, 12:10 am

Germany might have wind & solar, but they still generate 38% of their electric from dirty coal (in 2018), which is about as bad as you can get for the environment. Oddly enough, wind & solar is not 24-7.

Germany generated 242 TWh of power from coal in 2017 and the UK just 23TWh.

How the electricity is generated really matters & if you have a lot of it generated by coal, gas heating will be better for the environment than air to air.

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Re: Air to Air : Air Source Heating

#245203

Postby dspp » August 18th, 2019, 12:19 pm

jaizan wrote:Germany might have wind & solar, but they still generate 38% of their electric from dirty coal (in 2018), which is about as bad as you can get for the environment. Oddly enough, wind & solar is not 24-7.

Germany generated 242 TWh of power from coal in 2017 and the UK just 23TWh.

How the electricity is generated really matters & if you have a lot of it generated by coal, gas heating will be better for the environment than air to air.


I fully agree that coal is pretty dire in this respect, however they are working pretty hard to eliminate coal. And of course (rightly or wrongly) they switched the emphasis to prioritise shutting down the nuclear plant post-Fukushima so one can't have it both ways. Either way gets to pretty much the same destination in the end.

"On 26 January 2019, a group of federal and state leaders as well as industry representatives, environmentalists, and scientists made an agreement to close all 84 coal plants in the country by 2038. The move is projected to cost €40 billion in compensation alone to closed businesses. Coal was used to generate almost 40% of the country's electricity in 2018 and is expected to be replaced by renewable energy. 24 coal plants are planned to be closed by 2022 with all but 8 closed by 2030. The final date is expected to be assessed every 3 years."

https://en.wikipedia.org/wiki/Energy_in ... Coal_power
https://www.reuters.com/article/us-germ ... SKCN1PK04L


regards, dspp

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Re: Air to Air : Air Source Heating

#245220

Postby gryffron » August 18th, 2019, 1:16 pm

I too have looked at this as an option. From what I have read...

Efficiency of ASH is great down to about 5degC, below which it starts to drop off VERY quickly due to de-icing protocols, until about -10degC where it packs in completely. So it is very good heating, until you really need it!

So what are the majority of the UK supposed to do in such cases? Temperatures in UK don't very often get to -10degC, but are very commonly below 5degC on a winter's morning, when the heating is generally working hardest. Wood burners, or retreating to just the core parts of the house, aren't much of an option for the majority of households.

Gryff

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Re: Air to Air : Air Source Heating

#245261

Postby dspp » August 18th, 2019, 5:00 pm

gryffron wrote:I too have looked at this as an option. From what I have read...

Efficiency of ASH is great down to about 5degC, below which it starts to drop off VERY quickly due to de-icing protocols, until about -10degC where it packs in completely. So it is very good heating, until you really need it!

So what are the majority of the UK supposed to do in such cases? Temperatures in UK don't very often get to -10degC, but are very commonly below 5degC on a winter's morning, when the heating is generally working hardest. Wood burners, or retreating to just the core parts of the house, aren't much of an option for the majority of households.

Gryff


ASHP designed to deliver 'full' heating in such circumstances become pure electrical heaters, i.e. the heat pump part of the kit becomes useless. So for (say) 364 days of the year they get the benefit of a CoP that is (say) 3:1, and for (say) one day of the year they operate with a CoP of 1:1.

- dspp

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Re: Air to Air : Air Source Heating

#245300

Postby gryffron » August 18th, 2019, 8:54 pm

dspp wrote:ASHP designed to deliver 'full' heating in such circumstances become pure electrical heaters, i.e. the heat pump part of the kit becomes useless. So for (say) 364 days of the year they get the benefit of a CoP that is (say) 3:1, and for (say) one day of the year they operate with a CoP of 1:1.

Do they actually have a heater element? Oh, are you saying some systems do?
But it is sub 5degC many cold winter mornings. Even today with global warming et al. So it is certainly not going to be operating at full efficiency for 364 days of the year. Or even close. And the times when you need most heating it is least efficient.

Gryff - definitely sticking with gas, for now.

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Re: Air to Air : Air Source Heating

#245313

Postby fisher » August 18th, 2019, 10:01 pm

gryffron wrote:I too have looked at this as an option. From what I have read...

Efficiency of ASH is great down to about 5degC, below which it starts to drop off VERY quickly due to de-icing protocols, until about -10degC where it packs in completely. So it is very good heating, until you really need it!

So what are the majority of the UK supposed to do in such cases? Temperatures in UK don't very often get to -10degC, but are very commonly below 5degC on a winter's morning, when the heating is generally working hardest. Wood burners, or retreating to just the core parts of the house, aren't much of an option for the majority of households.

Gryff


I think you're being pessimistic about the efficiency. I have a NIBE 2040-16 ASHP which has been in for over 5 years. It works well for us and is economical. We have no access to gas so prior to this we had an oil boiler.

For this heat pump some COP examples are:
Cop of 4.65 to produce 35 degrees water when 7 degrees outside
Cop of 2.84 to produce 45 degrees water when 2 degrees outside
Cop of 2.42 to produce 45 degrees water when -7 degrees outside
Cop of 1.99 to produce 55 degrees water when -7 degrees outside
Cop of 1.89 to produce 45 degrees water when -15 degrees outside

At around 0 degrees and below outside we heat the radiator water to 50 degrees.

More NIBE statistics are available here:

https://www.google.com/url?sa=t&source= ... abGESOc78g


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