240v power?

[TheBiscuits]

1 minute ago, dmr said:

Surely this is just basic heat pump stuff (in reverse)? and why a lot of people are now fitting heat pumps in place of central heating boilers. A good heatpump installation can put about 3kW of heat into a house for each 1kW of electricity that it uses.   An A/C just sends the heat the other way, in fact I believe some can work in either direction.

Yeah, that.

 

For some reason it's easier the other way, so you will often see a unit cited as 2.5kW cooling and 4kW heating for a 1.5 kW electrical input.  Maybe they just count the waste heat off the motor as being a boost to heating and a detriment to cooling!

3 minutes ago, jaime66 said:

Its green energy ....you need 1kw to run compressor 

 

 

From the canal water in this case actually. 

 

It's not magic, it's physics, but remember what Arthur C. Clarke said ...

 

"Any sufficiently advanced technology is indistinguishable from magic."

[Alan de Enfield]

30 minutes ago, jaime66 said:

All modern AC units run with inverter to power the compressor so no high amp draw on start up ....if they can build Pyramids  sure we can get a AC unit to work lol 

You don't see many pyramids on narrowboats either (wonder why ?)

 

Edited May 22, 2020 by Alan de Enfield

[TheBiscuits]

2 minutes ago, Alan de Enfield said:

You don't see many pyramids on narrowboats either (wonder why ?)

 

Too hot to build them without aircon ...

[WotEver]

35 minutes ago, dmr said:

Surely this is just basic heat pump stuff (in reverse)? and why a lot of people are now fitting heat pumps in place of central heating boilers. A good heatpump installation can put about 3kW of heat into a house for each 1kW of electricity that it uses.   An A/C just sends the heat the other way, in fact I believe some can work in either direction.

 

..................Dave

That still doesn't explain where the other 1.5kW comes from.

 

33 minutes ago, jaime66 said:

Its green energy ....you need 1kw to run compressor 

Nor does that.

[WotEver]

 

I can understand ground source heat pumps because they are extracting the heat from the earth. But an aircon pumps refrigerant around, and uses say 1kW to pump it around.  Therefore, it's a 1kW aircon...

[TheBiscuits]

4 minutes ago, WotEver said:

I can understand ground source heat pumps because they are extracting the heat from the earth. But an aircon pumps refrigerant around, and uses say 1kW to pump it around.  

 

Yep.

 

4 minutes ago, WotEver said:

Therefore, it's a 1kW aircon...

 

Nope.  It shifts 2.5kW of heat from the hotter side to the cooler side - virtually none of which is the supplied electrical power...

 

 

It's still not magic.  In this particular case it's a water source heat pump which works just like a ground source heat pump but runnier.  The extra energy comes out of the canal water.  See the new green district heating scheme in Birmingham for more details.

 

I'd love a well designed heat pump system that gives me 2.5kW of air conditioning or 4kW blown air heating at the flick of a switch on my boat - simple enough with a good coil under the baseplate - but I can't provide the continuous 1.5 kW of electricity to run it while CCing.

 

It wouldn't make financial sense to install one on shorepower with electricity at 15p/kWh either so I can't see a big market for these on boats!

Edited May 22, 2020 by TheBiscuits

[mrsmelly]

My son in law works for Princess yachts and I can probably get you 100k discount on one, they have air con fitted as standard.

[WotEver]

8 minutes ago, TheBiscuits said:

It shifts 2.5kW of heat from the hotter side to the cooler side - virtually none of which is the supplied electrical power...

Nahhh... that’s magic...

[OldGoat]

Thinking sideways -

 

There's only one canal type boat that I've ever seen with A/C and that's on the Thames with a girt big condener on the rear deck. I don't thin he runs it - the windows are often open.....

 

Last year we were stuck (hot) below Banbury and it was V.hot sunshine. Most unloeasant inside until we opend all the doors and ran my trusty ex mainframe radial fans to shift the air a bit. I think it was 31 degrees outside...

 

The KISS principle applies to most things - including boats. Make sure you've got good or better insulation in the first place. If no how about a huge awning over the whole boat??

[TheBiscuits]

1 minute ago, OldGoat said:

how about a huge awning over the whole boat??

 

A 60 ft pram hood?  Wash your mouth out!

 

[Alan de Enfield]

27 minutes ago, TheBiscuits said:

I'd love a well designed heat pump system that gives me 2.5kW of air conditioning or 4kW blown air heating at the flick of a switch on my boat - simple enough with a good coil under the baseplate - but I can't provide the continuous 1.5 kW of electricity to run it while CCing.

They are fairly common on 'blue-water boats'. One of the Cats we looked at had the Dometic system fitted

 

https://www.dometic.com/en-gb/uk/products/b2b/yacht-and-ship-design/yacht-and-boat-equipment/yacht-and-boat-air-conditioners/dometic-chc-_-21013#specifications

 

As you say, the problem is that it draws 8.5 amps on cooling and 9.9 amps on heating and has a 95 amp starting current

However, this is not a problem when you have an inbuilt water cooled diesel generator.

Edited May 22, 2020 by Alan de Enfield

[OldGoat]

Just now, TheBiscuits said:

 

A 60 ft pram hood?  Wash your mouth out!

 

What a brilliant idea - what's the quotation ' a blot on the faced of a well loved friend'.

Don't do it by halves...

I was thinking more of the booze tent at County Shows...

[TheBiscuits]

2 minutes ago, OldGoat said:

I was thinking more of the booze tent at County Shows...

That's my usual sort of place to go when it's too hot on the boat, or one of the old inns with three foot thick stone walls that are lovely and cool ...

 

 

7 minutes ago, Alan de Enfield said:

As you say, the problem is that it draws 8.5 amps on cooling and 9.9 amps on heating and has a 95 amp starting current

However, this is not a problem when you have an inbuilt water cooled diesel generator.

 

That's a pretty big genny to give 95A at 240V!  I see that the unit is quoted as being "for larger boats in the 45-70 ft/15-20 m range." - perfect for a narrowboat then ...

[dmr]

1 hour ago, TheBiscuits said:

Yeah, that.

 

For some reason it's easier the other way, so you will often see a unit cited as 2.5kW cooling and 4kW heating for a 1.5 kW electrical input.  Maybe they just count the waste heat off the motor as being a boost to heating and a detriment to cooling!

 

From the canal water in this case actually. 

 

It's not magic, it's physics, but remember what Arthur C. Clarke said ...

 

"Any sufficiently advanced technology is indistinguishable from magic."

I have pondered that if we ever take a long term mooring (with mains) then a heat pump working with canal water would be an attractive green way to heat the boat. From what I have read the issue is that you only get low grade heat, lots of it but at a low temperature, so need Huge radiators, and its no good unless you live in a well insulated house (boat).

 

If 12 volt fridges were not so costly a good solution would be to get lots of fridges on the boat and keep the doors firmly closed. ?

 

................Dave

[Slim]

1 hour ago, Alan de Enfield said:

As you say, the problem is that it draws 8.5 amps on cooling and 9.9 amps on heating and has a 95 amp starting current

However, this is not a problem when you have an inbuilt water cooled diesel generator.

Not so sure. Once chartered a yacht in Ireland with a/c and an inbuilt water cooled diesel generator. A heavy night in a Kerry pub (Guinness). Back on board it was really hot so fired up a/c and generator (we were on anchor). 3am whole crew came out of their comas and shouted for silence. Never fired it up again.

[David Mack]

1 hour ago, OldGoat said:

What a brilliant idea - what's the quotation ' a blot on the face of a well loved friend'.

...monstrous carbuncle...

 

[Prince Charles, 30 May, 1984

https://www.princeofwales.gov.uk/speech/speech-hrh-prince-wales-150th-anniversary-royal-institute-british-architects-riba-royal-gala]

[Detling]

3 hours ago, dmr said:

Surely this is just basic heat pump stuff (in reverse)? and why a lot of people are now fitting heat pumps in place of central heating boilers. A good heatpump installation can put about 3kW of heat into a house for each 1kW of electricity that it uses.   An A/C just sends the heat the other way, in fact I believe some can work in either direction.

 

..................Dave

True and that is the advert blurb. What isn't mentioned is that 1 unit of electric is about 3 times the price of gas of the same energy. The output water temp is about 35 to 40 degrees not the 60 from a gas boiler, so your radiators have to be double the size. I am in the process of refurbing a Victorian house and after investigation have bought a gas boiler and smaller radiators.

[ditchcrawler]

10 minutes ago, Detling said:

True and that is the advert blurb. What isn't mentioned is that 1 unit of electric is about 3 times the price of gas of the same energy. The output water temp is about 35 to 40 degrees not the 60 from a gas boiler, so your radiators have to be double the size. I am in the process of refurbing a Victorian house and after investigation have bought a gas boiler and smaller radiators.

I understand that is what makes it better for underfloor heating

[nicknorman]

9 minutes ago, Detling said:

True and that is the advert blurb. What isn't mentioned is that 1 unit of electric is about 3 times the price of gas of the same energy. The output water temp is about 35 to 40 degrees not the 60 from a gas boiler, so your radiators have to be double the size. I am in the process of refurbing a Victorian house and after investigation have bought a gas boiler and smaller radiators.

I think heat pumps are pretty good with underfloor heating, for which you don’t want a very high water circulation temperature and you have a very large area of “radiator”, aka the floor. Also worth bearing in mind that lots of people aren’t on mains gas, and delivered gas is quite a lot more expensive.

[ditchcrawler]

1 minute ago, nicknorman said:

I think heat pumps are pretty good with underfloor heating, for which you don’t want a very high water circulation temperature and you have a very large area of “radiator”, aka the floor. Also worth bearing in mind that lots of people aren’t on mains gas, and delivered gas is quite a lot more expensive.

And they are going to ban it anyway

[WotEver]

15 minutes ago, ditchcrawler said:

And they are going to ban it anyway

Only for new builds, and not for another 5 years.  If it happens.

[ditchcrawler]

12 hours ago, WotEver said:

Only for new builds, and not for another 5 years.  If it happens.

Funny old world, when I was but a young apprentice boy the Eastern Electricity Board would lay all the cabling on a new housing estate for free, up to every meter point on every house if the developer DIDN'T have any gas mains laid on the estate.

[David Mack]

39 minutes ago, ditchcrawler said:

Funny old world, when I was but a young apprentice boy the Eastern Electricity Board would lay all the cabling on a new housing estate for free, up to every meter point on every house if the developer DIDN'T have any gas mains laid on the estate.

My in-laws house was built in the 1960s on an estate without gas, and the central heating was oil fired. In the 70s the Gas Board would provide a gas connection to each property for free, if enough residents would sign up to take gas, which they did. And so the oil tank went. 

A couple of years ago I enquired about getting our house connected to gas - the existing supply pipe ends less than 100 yards away and has sufficient spare capacity - and they wanted to charge me £14,000. We decided to stick with oil!

[nicknorman]

15 hours ago, dmr said:

I have pondered that if we ever take a long term mooring (with mains) then a heat pump working with canal water would be an attractive green way to heat the boat. From what I have read the issue is that you only get low grade heat, lots of it but at a low temperature, so need Huge radiators, and its no good unless you live in a well insulated house (boat).

 

If 12 volt fridges were not so costly a good solution would be to get lots of fridges on the boat and keep the doors firmly closed. ?

 

................Dave

I’m a bit slow to come back on this one, but heat pump vs mains gas uses roughly the same amount of energy and hence costs roughly the same to run. A gas boiler Is perhaps 90% efficient. Although a heat pump only uses 1/3rd of the energy at the point of use, to generate that electricity required more than 3 times as much energy (Power station and distribution efficiency). So the overall energy consumption is much the same, but with much higher initial costs. The only green advantage of the heat pump is if the electricity is generated “greenly” by solar, wind etc. And even then it depends on whether you find littering the countryside with ugly wind turbines and solar farms to be “green”. Carbon output vs Environmental damage I guess.

[dmr]

5 minutes ago, nicknorman said:

I’m a bit slow to come back on this one, but heat pump vs mains gas uses roughly the same amount of energy and hence costs roughly the same to run. A gas boiler Is perhaps 90% efficient. Although a heat pump only uses 1/3rd of the energy at the point of use, to generate that electricity required more than 3 times as much energy (Power station and distribution efficiency). So the overall energy consumption is much the same, but with much higher initial costs. The only green advantage of the heat pump is if the electricity is generated “greenly” by solar, wind etc. And even then it depends on whether you find littering the countryside with ugly wind turbines and solar farms to be “green”. Carbon output vs Environmental damage I guess.

I find wind turbines and wind farms to be attractive, the tips of the blades appearing over the brow of a hill is particularly satisfying, and knowing that they are producing (possibly) pollution free energy is a bonus.

 

But then I also find power station cooling towers attractive and enjoy boating past the old bottle kilns in Stoke on Trent ?.

 

We need to massively reduce our use of fossil fuels and heat pumps can play a part in this.

 

From my electronics days a lot of effort was spent handling excess heat so using electricity to directly make things hot still feels wrong, spinning a motor is a much better idea.,

 

................Dave