Firstly, thank you all for the replies so far.

When I have visited the USA I have stayed in hotels with a device
fitted under the window (therefore an outside wall). Most trips have
been in summer when such devices act as an air conditioner but in
winter they act as heaters. Are they a form of heat pump? The idea of
having such a dual purpose machine has some attractions.

On 05/04/2023 16:11, Graham Harrison wrote:
> Firstly, thank you all for the replies so far.
>
> When I have visited the USA I have stayed in hotels with a device
> fitted under the window (therefore an outside wall). Most trips have
> been in summer when such devices act as an air conditioner but in
> winter they act as heaters. Are they a form of heat pump? The idea of
> having such a dual purpose machine has some attractions.

heat pumps, fridges and air con all use the same principle
so a ?monoblock air-to-air system can do both heating and
cooling.

On Wed, 05 Apr 2023 16:11:45 +0100, Graham Harrison wrote:

> Firstly, thank you all for the replies so far.
>
> When I have visited the USA I have stayed in hotels with a device fitted
> under the window (therefore an outside wall). Most trips have been in
> summer when such devices act as an air conditioner but in winter they
> act as heaters. Are they a form of heat pump? The idea of having such a
> dual purpose machine has some attractions.

Yes they work both ways, this diagram is the cop versus temperature for an
air sourced heat pump:
https://ibb.co/bQLLzPp

On 05/04/2023 16:29, Smolley wrote:
> On Wed, 05 Apr 2023 16:11:45 +0100, Graham Harrison wrote:
>
>> Firstly, thank you all for the replies so far.
>>
>> When I have visited the USA I have stayed in hotels with a device fitted
>> under the window (therefore an outside wall). Most trips have been in
>> summer when such devices act as an air conditioner but in winter they
>> act as heaters. Are they a form of heat pump? The idea of having such a
>> dual purpose machine has some attractions.
>
> Yes they work both ways, this diagram is the cop versus temperature for an
> air sourced heat pump:
> https://ibb.co/bQLLzPp

Installation has to be considered. Those fitted under the window in
hotels are possibly only heating/cooling one room. For dual use central
heating would possibly have to be whole house air ducting.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

Graham Harrison <edward.harrisom.one@btinternet.com> wrote:
> Firstly, thank you all for the replies so far.
>
> When I have visited the USA I have stayed in hotels with a device
> fitted under the window (therefore an outside wall). Most trips have
> been in summer when such devices act as an air conditioner but in
> winter they act as heaters. Are they a form of heat pump? The idea of
> having such a dual purpose machine has some attractions.

They are, although they are not always designed to run in reverse (pumping
heat not cold into the room). For example they need defrost cycles when the
outdoor unit ices up. It doesn't take massive changes to make them
reversible, but it needs to be designed in. Additionally the efficiency of
a device designed primarily for cooling may not be as good in heating mode.

We would call them 'air to air heat pumps'. They have pluses and minuses
against traditional wet central heating.

Theo

alan_m <junk@admac.myzen.co.uk> wrote:
> On 05/04/2023 16:29, Smolley wrote:
> > On Wed, 05 Apr 2023 16:11:45 +0100, Graham Harrison wrote:
> >
> >> Firstly, thank you all for the replies so far.
> >>
> >> When I have visited the USA I have stayed in hotels with a device fitted
> >> under the window (therefore an outside wall). Most trips have been in
> >> summer when such devices act as an air conditioner but in winter they
> >> act as heaters. Are they a form of heat pump? The idea of having such a
> >> dual purpose machine has some attractions.
> >
> > Yes they work both ways, this diagram is the cop versus temperature for an
> > air sourced heat pump:
> > https://ibb.co/bQLLzPp

Beware that domestic ASHPs don't use R134a - they're mostly R290 or R32 (and
a few R700), with older ones being R410a. Every model of ASHP has different
COP performance. So your diagram is not very representative, although the
COP derating factor looks plausible.

> Installation has to be considered. Those fitted under the window in
> hotels are possibly only heating/cooling one room. For dual use central
> heating would possibly have to be whole house air ducting.

You can get multi-split systems, one outdoor box with multiple room units.
Just refrigerant pipework connecting them (+electrics and condensate drain).

US folks also have a/c units which fit in a window opening - they're leaky
and not very efficient, a bit like our portable a/c units.

Theo

I just wondered then, if a fridge would actually warm up the inside if you
put it into a really deep freeze like you might used to freeze co2.
Brian

--

--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
briang1@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
"Smolley" <s@home.net> wrote in message news:u0k44g$3ugm8$1@dont-email.me...
> On Wed, 05 Apr 2023 16:11:45 +0100, Graham Harrison wrote:
>
>> Firstly, thank you all for the replies so far.
>>
>> When I have visited the USA I have stayed in hotels with a device fitted
>> under the window (therefore an outside wall). Most trips have been in
>> summer when such devices act as an air conditioner but in winter they
>> act as heaters. Are they a form of heat pump? The idea of having such a
>> dual purpose machine has some attractions.
>
> Yes they work both ways, this diagram is the cop versus temperature for an
> air sourced heat pump:
> https://ibb.co/bQLLzPp

On 05/04/2023 17:20, Theo wrote:
> You can get multi-split systems, one outdoor box with multiple room units.
> Just refrigerant pipework connecting them (+electrics and condensate drain).
>

So can one of these splits run a unit with a coil in DHW tank to a low
temperature,say 40C? Which can be then boosted by an immersion?

> US folks also have a/c units which fit in a window opening - they're leaky
> and not very efficient, a bit like our portable a/c units.

The one we had fitted into a sash window and was a boon during the 40C
nights in Boston Massachusetts.

ajh <news@loampitsfarm.co.uk> wrote:
> On 05/04/2023 17:20, Theo wrote:
> > You can get multi-split systems, one outdoor box with multiple room units.
> > Just refrigerant pipework connecting them (+electrics and condensate drain).
> >
>
> So can one of these splits run a unit with a coil in DHW tank to a low
> temperature,say 40C? Which can be then boosted by an immersion?

No, they have no water interface to them. They're purely refrigerant lines
with fan-air heat exchangers at both ends. I've not seen DHW tanks with
refrigerant coils.

In the US they have separate heat pump water heaters, with either a single
tank+fan unit (installed somewhere like a garage in the South) or a water
tank with an external box (a bit like our ASHPs). They then use splits or a
ducted air system for space heating/cooling, so you can heat water and cool
the house at the same time.
https://www.youtube.com/watch?v=wt95SE2ogNI

You could I suppose fit a separate air2water ASHP for hot water in the UK if
you were going for room splits. They're not quite on the $1500 price point
of the US ones yet, though. Another issue is the US ones are designed for
heating water hotter than ours which are also designed for space heating
(hence different refrigerants).

> The one we had fitted into a sash window and was a boon during the 40C
> nights in Boston Massachusetts.

A lot of the world installs A/C without thinking about efficiency or
insulation, which explains why they spend so much on electricity.

Theo

On 10/04/2023 15:04, Theo wrote:
> ajh <news@loampitsfarm.co.uk> wrote:
>> On 05/04/2023 17:20, Theo wrote:
>>> You can get multi-split systems, one outdoor box with multiple room units.
>>> Just refrigerant pipework connecting them (+electrics and condensate drain).
>>>
>>
>> So can one of these splits run a unit with a coil in DHW tank to a low
>> temperature,say 40C? Which can be then boosted by an immersion?
>
> No, they have no water interface to them. They're purely refrigerant lines
> with fan-air heat exchangers at both ends. I've not seen DHW tanks with
> refrigerant coils.

Oh well that is what I wondered, a refrigerant coil in a DHW tank with
an immersion.

The thing is an air2water heat pump is three times as expensive as a
small air2air which would suit a house down to ~10C outside.

Ideally I would like air2water with underfloor and preheated DHW, making
use of off peak electricity in deepest winter but capital cost puts it
out for our old house.
>
> In the US they have separate heat pump water heaters, with either a single
> tank+fan unit (installed somewhere like a garage in the South) or a water
> tank with an external box (a bit like our ASHPs). They then use splits or a
> ducted air system for space heating/cooling, so you can heat water and cool
> the house at the same time.
> https://www.youtube.com/watch?v=wt95SE2ogNI

Yes seen them by Daiken and Valiant here.

>
> A lot of the world installs A/C without thinking about efficiency or
> insulation, which explains why they spend so much on electricity.

In my case A/C is only used a few days a year and that coincides with
high solar PV production.

Graham Harrison wrote:

> Firstly, thank you all for the replies so far.
>
> When I have visited the USA I have stayed in hotels with a device
> fitted under the window (therefore an outside wall). Most trips have
> been in summer when such devices act as an air conditioner but in
> winter they act as heaters. Are they a form of heat pump? The idea of
> having such a dual purpose machine has some attractions.

you can have reversible (as opposed to heat-only) ASHP, they are still
monobloc with only water connection going indoors, installer doesn't
need F-gas qualification, all the refrigerant stays outdoors and is
pre-filled.

The system as a whole would need solenoid valves and relays to control
which mode it's in and where the water flow goes to; in heating mode one
set of valves open to your HW cylinder and/or UFH, and be switchable to
cooling mode with another valve chilled water flows to wall mounted
fan/coil aircon unit.

Andy Burns <usenet@andyburns.uk> wrote:
> Graham Harrison wrote:
>
> > Firstly, thank you all for the replies so far.
> >
> > When I have visited the USA I have stayed in hotels with a device
> > fitted under the window (therefore an outside wall). Most trips have
> > been in summer when such devices act as an air conditioner but in
> > winter they act as heaters. Are they a form of heat pump? The idea of
> > having such a dual purpose machine has some attractions.
>
> you can have reversible (as opposed to heat-only) ASHP, they are still
> monobloc with only water connection going indoors, installer doesn't
> need F-gas qualification, all the refrigerant stays outdoors and is
> pre-filled.

Most water ASHP will actually do cooling too, but for historical
grant-related reasons some of them hide it by deleting sections of the UK
manual or hide it behind a setting. If you get the global manual it's all
documented there.

> The system as a whole would need solenoid valves and relays to control
> which mode it's in and where the water flow goes to; in heating mode one
> set of valves open to your HW cylinder and/or UFH, and be switchable to
> cooling mode with another valve chilled water flows to wall mounted
> fan/coil aircon unit.

Much like a regular heating system in fact. I'm thinking of adding another
zone for a fan coil, which would turn my system from S Plan to S Plan Plus.

Fan coils are a bit of a rare breed in the UK, although this is changing:
https://forum.buildhub.org.uk/topic/10658-fan-coil-units-for-use-with-a-cooling-ashp/

Theo

Theo wrote:

> Most water ASHP will actually do cooling too, but for historical
> grant-related reasons some of them hide it by deleting sections of the UK
> manual or hide it behind a setting. If you get the global manual it's all
> documented there.

Yes, I see that with some it's just a case of a pin header that needs a
resistor on a plug, presumably others would actually have the reversing
valve omitted for cost reasons?

>> The system as a whole would need solenoid valves and relays to control
>> which mode it's in and where the water flow goes to; in heating mode one
>> set of valves open to your HW cylinder and/or UFH, and be switchable to
>> cooling mode with another valve chilled water flows to wall mounted
>> fan/coil aircon unit.
>
> Much like a regular heating system in fact.

Other than not expecting a chilled flow from a combi!

> I'm thinking of adding another
> zone for a fan coil, which would turn my system from S Plan to S Plan Plus.
>
> Fan coils are a bit of a rare breed in the UK

Yes, one that I found last time I looked now says
"This product is not yet available"

Andy Burns <usenet@andyburns.uk> wrote:
> Theo wrote:
>
> > Most water ASHP will actually do cooling too, but for historical
> > grant-related reasons some of them hide it by deleting sections of the UK
> > manual or hide it behind a setting. If you get the global manual it's all
> > documented there.
>
> Yes, I see that with some it's just a case of a pin header that needs a
> resistor on a plug, presumably others would actually have the reversing
> valve omitted for cost reasons?

Most ASHP are a global product so are designed for markets where both
heating and cooling are used. There isn't much point in hobbling them for a
few bucks worth of components.

This one is 'designed for the UK' and maybe doesn't do cooling:
http://www.red-limited.com/uhe-heat-pump-products/

> > Much like a regular heating system in fact.
>
> Other than not expecting a chilled flow from a combi!

Just need to burn that magic anti-hydrogen :)

> > Fan coils are a bit of a rare breed in the UK
>
> Yes, one that I found last time I looked now says
> "This product is not yet available"

These look good, if a bit pricey:
https://coolenergyshop.com/collections/radiators-fan-coils

(going rate in Italy is about half that, but they're a PITA to order since
Brexit)

Theo

ajh <news@loampitsfarm.co.uk> wrote:
> On 10/04/2023 15:04, Theo wrote:
>
> Oh well that is what I wondered, a refrigerant coil in a DHW tank with
> an immersion.
>
> The thing is an air2water heat pump is three times as expensive as a
> small air2air which would suit a house down to ~10C outside.

How small is small? A small room a2a might be 9000BTU/hr or 2.7kW. Most
houses are going to need 2-4x that.

> Ideally I would like air2water with underfloor and preheated DHW, making
> use of off peak electricity in deepest winter but capital cost puts it
> out for our old house.

Depends on your sizing, but something like this is not far off boiler
pricing (especially oil boiler):
https://midsummerwholesale.co.uk/buy/samsung-heat-pumps/samsung-8kw-monobloc-heat-pump-AE080RXYDEGEU

> > In the US they have separate heat pump water heaters, with either a single
> > tank+fan unit (installed somewhere like a garage in the South) or a water
> > tank with an external box (a bit like our ASHPs). They then use splits or a
> > ducted air system for space heating/cooling, so you can heat water and cool
> > the house at the same time.
> > https://www.youtube.com/watch?v=wt95SE2ogNI
>
> Yes seen them by Daiken and Valiant here.

Ah, thanks I hadn't seen those. The Daikin one is quite hidden on their
site. Here is the Vaillant one:
https://midsummerwholesale.co.uk/buy/vaillant-heat-pumps/vaillant-arostor-200

(actually quite weedy: 700W input, COP=3.19, means output heat = 2.2kW)

Theo

On 10/04/2023 16:54, Andy Burns wrote:
> Theo wrote:
>
>> Most water ASHP will actually do cooling too, but for historical
>> grant-related reasons some of them hide it by deleting sections of the UK
>> manual or hide it behind a setting.  If you get the global manual it's
>> all
>> documented there.
>
> Yes, I see that with some it's just a case of a pin header that needs a
> resistor on a plug, presumably others would actually have the reversing
> valve omitted for cost reasons?

In a tradition water based CH heating with underfloor or radiators would
reversing the system and circulating cold water actually produce a
comfortable environment in summer? Radiators drop the the cooled air to
the floor and with underfloor piping you would get cold feet. You then
need to get this cold air to fully circulate in the rooms by using fans.

--
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alan_m <junk@admac.myzen.co.uk> wrote:
> On 10/04/2023 16:54, Andy Burns wrote:
>> Theo wrote:
>>
>>> Most water ASHP will actually do cooling too, but for historical
>>> grant-related reasons some of them hide it by deleting sections of the UK
>>> manual or hide it behind a setting.  If you get the global manual it's
>>> all
>>> documented there.
>>
>> Yes, I see that with some it's just a case of a pin header that needs a
>> resistor on a plug, presumably others would actually have the reversing
>> valve omitted for cost reasons?
>
> In a tradition water based CH heating with underfloor or radiators would
> reversing the system and circulating cold water actually produce a
> comfortable environment in summer?

I doubt it. You’d also get condensation dripping off the radiators. You
really need zone controlled fanned units (with condensate drains) to spread
the “coolth” properly I reckon.

Tim

--
Please don't feed the trolls

On 10/04/2023 17:12, Theo wrote:

> These look good, if a bit pricey:
> https://coolenergyshop.com/collections/radiators-fan-coils
>
> (going rate in Italy is about half that, but they're a PITA to order since
> Brexit)

I know of people who find the noise of a fan in a laptop or PC annoying
especially if they are the one not using the equipment so a fanned
solution may not be ideal for all.

I wonder how much those fanned radiators concentrate the dust to the
wall above/beneath the installation leaving black marks on the walls.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

alan_m <junk@admac.myzen.co.uk> wrote:
> On 10/04/2023 16:54, Andy Burns wrote:
> > Theo wrote:
> >
> >> Most water ASHP will actually do cooling too, but for historical
> >> grant-related reasons some of them hide it by deleting sections of the UK
> >> manual or hide it behind a setting.  If you get the global manual it's
> >> all
> >> documented there.
> >
> > Yes, I see that with some it's just a case of a pin header that needs a
> > resistor on a plug, presumably others would actually have the reversing
> > valve omitted for cost reasons?
>
> In a tradition water based CH heating with underfloor or radiators would
> reversing the system and circulating cold water actually produce a
> comfortable environment in summer? Radiators drop the the cooled air to
> the floor and with underfloor piping you would get cold feet. You then
> need to get this cold air to fully circulate in the rooms by using fans.

Rads don't work for cooling unless you mount them upside down. The cold
water goes from inlet to outlet without troubling the warmer water in the
rest of the rad, meaning only the bottom few inches are cold. When heating
you pump in hotter water at the bottom which rises, establishing a
convection cell. You'd only get that for cooling if the cold water went in
at the top forcing mixing with the warmer water inside.

UFH can work for cooling - the cold stone floor effect. You need to make
sure it's not cold enough to get condensation (or run a dehumidifier as
well). UFH plus ceiling fans might work nicely.

Theo

alan_m <junk@admac.myzen.co.uk> wrote:
> I know of people who find the noise of a fan in a laptop or PC annoying
> especially if they are the one not using the equipment so a fanned
> solution may not be ideal for all.

Any kind of air conditioning requires a fan. I suppose apart from just
dumping a block of ice in the middle of the room. Or maybe mounting cooling
radiators on the ceiling.

> I wonder how much those fanned radiators concentrate the dust to the
> wall above/beneath the installation leaving black marks on the walls.

No idea, but ask any user of an air conditioner in the rest of the world and
they'll tell you.

Theo

Theo wrote:

> Rads don't work for cooling unless you mount them upside down. The cold
> water goes from inlet to outlet without troubling the warmer water in the
> rest of the rad, meaning only the bottom few inches are cold. When heating
> you pump in hotter water at the bottom which rises, establishing a
> convection cell. You'd only get that for cooling if the cold water went in
> at the top forcing mixing with the warmer water inside.

You could pipe the radiators TBOE, but you'd need to reverse the pump
direction for cooling compared to heating.

Andy Burns <usenet@andyburns.uk> wrote:
> Theo wrote:
>
> > Rads don't work for cooling unless you mount them upside down. The cold
> > water goes from inlet to outlet without troubling the warmer water in the
> > rest of the rad, meaning only the bottom few inches are cold. When heating
> > you pump in hotter water at the bottom which rises, establishing a
> > convection cell. You'd only get that for cooling if the cold water went in
> > at the top forcing mixing with the warmer water inside.
>
> You could pipe the radiators TBOE, but you'd need to reverse the pump
> direction for cooling compared to heating.

I suppose that would work - not sure how difficult reversing would be. It
might work where there's hydraulic separation, but not if they're pumped
directly from the ASHP (which can't reverse). Maybe you'd need valves to
flip around the rad circuit, keeping the pump going forward.

Wouldn't be ideal even then, as you'd get condensation on the rads.

Fan coils are a better bet...

Theo

On 10/04/2023 21:29, Theo wrote:
> alan_m <junk@admac.myzen.co.uk> wrote:
>> I know of people who find the noise of a fan in a laptop or PC annoying
>> especially if they are the one not using the equipment so a fanned
>> solution may not be ideal for all.
>
> Any kind of air conditioning requires a fan. I suppose apart from just
> dumping a block of ice in the middle of the room. Or maybe mounting cooling
> radiators on the ceiling.
>
>> I wonder how much those fanned radiators concentrate the dust to the
>> wall above/beneath the installation leaving black marks on the walls.
>
> No idea, but ask any user of an air conditioner in the rest of the world and
> they'll tell you.

They have good fine filters. Never noticed any marks in either the UK or
Spain. My son has some in Qatar that are always on. Again not dust.
When you clean them you can get a lot of muck out of them....

>
> Theo

Dave

On Tue, 11 Apr 2023 05:36:32 +1000, alan_m <junk@admac.myzen.co.uk> wrote:

> On 10/04/2023 16:54, Andy Burns wrote:
>> Theo wrote:
>>
>>> Most water ASHP will actually do cooling too, but for historical
>>> grant-related reasons some of them hide it by deleting sections of the
>>> UK
>>> manual or hide it behind a setting. If you get the global manual it's
>>> all
>>> documented there.
>> Yes, I see that with some it's just a case of a pin header that needs
>> a resistor on a plug, presumably others would actually have the
>> reversing valve omitted for cost reasons?

> In a tradition water based CH heating with underfloor or radiators would
> reversing the system and circulating cold water actually produce a
> comfortable environment in summer?

Never noticed anyone doing that, so that's unlikely.

Tho that may be because hardly anyone but you poms use
water based CH heating with underfloor or radiators and
you lot don't really get many days when cooling is needed.

> Radiators drop the the cooled air to the floor and with underfloor
> piping you would get cold feet.

But I feel the heat more in my feet when I am sitting around
in the hottest weather and thats with bare feet which is what
I have right thru the spring, summer and autumn.

> You then need to get this cold air to fully circulate in the rooms by
> using fans.

Not necessarily with the anaemic hot spellsyou lot get.

You wanna try 10 days in a row of 48C max.

On Tue, 11 Apr 2023 05:46:50 +1000, alan_m <junk@admac.myzen.co.uk> wrote:

> On 10/04/2023 17:12, Theo wrote:
>
>> These look good, if a bit pricey:
>> https://coolenergyshop.com/collections/radiators-fan-coils
>> (going rate in Italy is about half that, but they're a PITA to order
>> since
>> Brexit)
>
>
> I know of people who find the noise of a fan in a laptop or PC annoying
> especially if they are the one not using the equipment so a fanned
> solution may not be ideal for all.

I have never heard of anyone here compaining about the
noise of the aircon or fans when its too hot to do without.

> I wonder how much those fanned radiators concentrate the dust to the
> wall above/beneath the installation leaving black marks on the walls.