Reverse cycle air con / heating info

[superheat6k]

As QUOTE by superheat6k

"I practice this subject for my living, and at home I recently fitted a condensing boiler, not an air source heatpump."


I am Agreed. The technology has not yet reached the efficiency / life span cost benefit needed.

Incidently, your username, I used a product called just that many moons ago, originally available on a floppy way back then, to calculate building heat loss, is that yours?

Superheat is the temperature of a gas above its saturation (boiling) point. In a fridge system 6K (6 degrees Kelvin or 6oC of absolute measurement) is the ideal temperature of the gas returning to the compressor to ensure no liquid refrigerant will enter the compressor.

As a compressor remanufacturer wishing to reduce warranties having every system to which we supply a remanufactured compressor operate at 6K superheat suction is close to heaven, as long as the customer has also renewed the contactor, but thats another story.

6 degrees of superheat is the standard setting for a conventional Thermostatic Expansion Valve, although we now run modern electronic valves at 5 or even 4K.

Well you did ask !

 

[Cathy*]

thanks Cathy.
Just checking, they seem to be a farming machinery firm, it's not some Ex tractor fan joke is it...

No, but I live with a tractor fan and they did talk tractors while doing the job. We originally contacted Mountbatten boathouse because they were listed somewhere as Cruisair suppliers. They don't do them anymore and told us to contact Ball and Ball as they always use them now for regassing. Our boat is 8 years old and the air con had stopped giving any heat. It cost us about £200 to have the 2 done. The water down here is showing 9 degrees on a dive computer and they're still working ok, Our Eberscher literature says the diesel heating will use .28 litres an hour on minimum so roughly 6 litres (£6) a day. The A/C is working out at less than £2.50 a day.

 

[lambohill]

Well you did ask !

Indeed I did!
And the wiser I am for it.

 

[Andrew M]

Well a good bit of googling and a couple of hours faff and I have hot air coming from each of the 5 head units

The valve in one was struck but it pushed across and down and seems to be working well now...

I have one thermostat that is reading 10 c above actual...trying to find a cruisair spares dealer in the UK seems like fun

I''ve discovered I've got one zone that won't push out any heat into 2 cabins, no fault code showing on that control panel so I'm wondering if it is a sticking valve, it probably hasn't been used in heat mode by previous owner for anything up to 5 or 6 years.

Did you resolve your heat valve by moving it by hand ? Most of the solutions I can see so far involve "whacking" it with a screwdriver handle.

Thanks,

Andy

 

[Nigelpickin]

We

I''ve discovered I've got one zone that won't push out any heat into 2 cabins, no fault code showing on that control panel so I'm wondering if it is a sticking valve, it probably hasn't been used in heat mode by previous owner for anything up to 5 or 6 years.

Did you resolve your heat valve by moving it by hand ? Most of the solutions I can see so far involve "whacking" it with a screwdriver handle.

Thanks,

Andy

Andy

A gentle tap didn't work so I used a flat head screwdriver snd pushed the lever across and down.
I'm on the boat in an hour or so, can take a picture if that's any help...let me know.

Regards
Nigel

 

[Andrew M]

Great, if you could do a pic that would be really helpful. Ours is a cruisair system.

Once you freed yours has it moved on it's own as it should or do you think it's a manual job until it gets replaced ?

Thanks,

Andy

 

[Nigelpickin]

Great, if you could do a pic that would be really helpful. Ours is a cruisair system.

Once you freed yours has it moved on it's own as it should or do you think it's a manual job until it gets replaced ?

Thanks,


Andy

Andy,

Teenager was on boat Saturday and reports all working well...but he is a teenager!
I'll let you know a before lunch and take the photo.

I'll run the system up in cold and then switch to heat....cheers.

 

[Nigelpickin]

Great, if you could do a pic that would be really helpful. Ours is a cruisair system.

Once you freed yours has it moved on it's own as it should or do you think it's a manual job until it gets replaced ?

Thanks,

Andy

http://i1173.photobucket.com/albums...9-412C-9B78-76C987795805.png_zpsj951mbsj.jpeg

Andy

Switch was ok today, link above to an image of the poptop actuator.

The lever needs a pretty stern push to the side and then lock in place by pushing down. I used a screwdriver for this as access is tight for me.

I would try using it a few times and see if it comes good.

FWIW I'm going to get a couple of spares and fit one when I'm up the coast later next month, just to see how it's done and to have in case the problem reoccurs....

Cheers

 

[Andrew M]

Brilliant, thanks Nigel, at least I know what to look for now.

Will give it a try when we're down there next.

Thanks,

Andy

 

[wonky]

Thread drift but anyone have experience of the water heating type of heating...radiators etc? Webasto do it.

 

[Bmc]

Hi guys . Looking for some advice please. Looking to fit Eberspacher air heating on my boat. Can I use my existing reverse cycle hot / cold ducting instead of installing additional ducting.

 

[Plum]

Hi guys . Looking for some advice please. Looking to fit Eberspacher air heating on my boat. Can I use my existing reverse cycle hot / cold ducting instead of installing additional ducting.

The air temperature from an eberspacher will be much higher than that from a heat-pump so you need to ensure the ducting can cope

 

[Grubble]

Make the most of AC anyway - the recent law revision (F Gas Directive review) governing what we can use mean that most available refrigerants we currently use will be non available over the next 10-15 years anyway, and the implications for this not just for boat cooling, but all cooling are not yet fully appreciated. The replacements the EU want us to use instead haven't all been invented yet, and for some applications it is unlikely safe non flammable gases will be available much after 2025. This isn't just the recently banned R22, but all gases with R134a in - effectively all R400 series gases.

With 2025 fast approaching, what did the industry invent to comply with the new regulations?

 

[jfm]

Also airco systems typically prioritise the cooling function over the heating function, and therefore the ducting squirts air into the top of a room, whereas you want heating ducting ideally to squirt warm air into the bottom of the room. Not a life or death point of course.

 

[superheat6k]

With 2025 fast approaching, what did the industry invent to comply with the new regulations?

Well it decided to mostly use R32, which is the higher pressure half of R410A. It has a lower GWP, but the sheer volume of R32 that is forecast to be used over the next few years will considerably exceed what the politicians are allowing us to use in terms of CO2 tonnes. Hence R32 is really an interim choice, but the other alternatives for heat pumps are not yet developed - despite Ed Milliband requiring us all to fit heat pumps to heat our homes.

I am due to retire - but I do foresee massive problems ahead for the entire concept of compression / expansion refrigeration and air-conditioning (including heat pumps). On one hand they want us to use heat pumps, on the other they are banning the fluids we need to achieve the desired tasks.

 

[Grubble]

Well it decided to mostly use R32, which is the higher pressure half of R410A. It has a lower GWP, but the sheer volume of R32 that is forecast to be used over the next few years will considerably exceed what the politicians are allowing us to use in terms of CO2 tonnes. Hence R32 is really an interim choice, but the other alternatives for heat pumps are not yet developed - despite Ed Milliband requiring us all to fit heat pumps to heat our homes.

I am due to retire - but I do foresee massive problems ahead for the entire concept of compression / expansion refrigeration and air-conditioning (including heat pumps). On one hand they want us to use heat pumps, on the other they are banning the fluids we need to achieve the desired tasks.

And R32 is backwardly compatible? I've got quite a few domestic aircon units between 10 and 1 years old, so the majority of them will have the previous standard.

For new build homes insulation requirements are going up, so then the heating/cooling needed will be lower - both will help meet the target of reducing carbon emissions from new homes by 30%. If heat pumps can't do it alone, then they will need to increase insulation.

We are going off topic now, but it is an interesting one.

 

[jfm]

Well it decided to mostly use R32, which is the higher pressure half of R410A. It has a lower GWP, but the sheer volume of R32 that is forecast to be used over the next few years will considerably exceed what the politicians are allowing us to use in terms of CO2 tonnes. Hence R32 is really an interim choice, but the other alternatives for heat pumps are not yet developed - despite Ed Milliband requiring us all to fit heat pumps to heat our homes.

I am due to retire - but I do foresee massive problems ahead for the entire concept of compression / expansion refrigeration and air-conditioning (including heat pumps). On one hand they want us to use heat pumps, on the other they are banning the fluids we need to achieve the desired tasks.

Interesting update sh6k - many thanks

 

[superheat6k]

And R32 is backwardly compatible? I've got quite a few domestic aircon units between 10 and 1 years old, so the majority of them will have the previous standard.

For new build homes insulation requirements are going up, so then the heating/cooling needed will be lower - both will help meet the target of reducing carbon emissions from new homes by 30%. If heat pumps can't do it alone, then they will need to increase insulation.

We are going off topic now, but it is an interesting one.

My own business specialises in retrofit of Air Con equipment, mostly water chillers.

Bad news I am afraid as far as backward compatibility of smaller split style equipment is concerned, but no doubt some folk will try it - expect early failures post retrofit.

R410A has no refrigerant for sensible retrofit without significant changes and likely a loss of machine capacity. R32 on its own is not compatible with R410A systems because the operating pressures and temperatures are significantly different (higher pressures).

R32 which is 50% of R410A (a blend of R32 & R125) also has no viable direct replacements, although there is a similar refrigerant R454B that is itself a blend (R32 69% plus R1234YF 31%), but thus far it is to early in use to be verified as a suitable replacement for R32.

There is a separate issue with R32, R454B and R1234YF (which is itself a close replacement for R134a but only in new or extensively upgraded equipment) are all partially flammable.

The separate issue is Global Warming Potential or GWP which is measured in CO2 tonnes equivalency where a GWP of 1 = 1kg equates in the atmosphere to 1 tonne of CO2.

GWP is the driving political consideration.

So consider these GWP ratings for gases commonly associated with boat borne AC and fridge equipment ...

R410A 2088 (blend - above)
R407C 1774 (blend widely used in equipment as a replacement for long banned R22)
R134a 1430 (mostly used for fridges and also car air con)
R32 675 (single molecule, A2L low flammability)
R513A 631 (a blend of R134a with R1234YF to emulate R134a, non flammable but lower GWP - mostly for larger equipment - we use it in water chillers)
R454B 467 (being used to provide a slightly lower GWP than R32 but I do not think is is suitable as an R32 replacement in the same equipment (I am still in the discovery process), A2L low flammability)
R1234YF 4 i.e. very low compared with the above list (mostly used in car air-con, A2L low flammability)

The major manufacturers of smaller kit for AC ashore are using R32, so expect most marine systems to follow.

But the sheer volume of R32 equipment coming onto the market, (not least domestic heat pumps) likely means the entire allowed CO2 tonnage for the entire industry will within a few years be taken up by R32 alone. We are no longer in the lead on this, but EU Politicians are only talking about more draconian phase down of refrigerants, so here there is a clear conflict in one environmental consideration (reducing CO2 in general) being at logger heads with another reducing (reducing refrigerant CO2 tonnage).

Boat use of AC and refrigeration is small beer in this discussion. No clear answers yet, but I am informed the chemical cupboard for new gases is now empty.

 

[John100156]

Aaaaah gone are the days/many years of using R12 for cold rooms and R22 for AC, with a squirt of R22 Dytel to help find minor leaks....... IIRC they found it was carcinogenic, I used it often!

 

[Grubble]

R410A 2088 (blend - above)
R407C 1774 (blend widely used in equipment as a replacement for long banned R22)
R134a 1430 (mostly used for fridges and also car air con)
R32 675 (single molecule, A2L low flammability)
R513A 631 (a blend of R134a with R1234YF to emulate R134a, non flammable but lower GWP - mostly for larger equipment - we use it in water chillers)
R454B 467 (being used to provide a slightly lower GWP than R32 but I do not think is is suitable as an R32 replacement in the same equipment (I am still in the discovery process), A2L low flammability)
R1234YF 4 i.e. very low compared with the above list (mostly used in car air-con, A2L low flammability)

The major manufacturers of smaller kit for AC ashore are using R32, so expect most marine systems to follow.

But the sheer volume of R32 equipment coming onto the market, (not least domestic heat pumps) likely means the entire allowed CO2 tonnage for the entire industry will within a few years be taken up by R32 alone. We are no longer in the lead on this, but EU Politicians are only talking about more draconian phase down of refrigerants, so here there is a clear conflict in one environmental consideration (reducing CO2 in general) being at logger heads with another reducing (reducing refrigerant CO2 tonnage).

Those numbers you have posted really are an eye-opener on the differences between the different gases - I had no idea the range was so huge (even between R410A and the 2025 spec R32 gas).

For your last point, I suppose you would have to do the calculation of how much CO2 is saved by heat pumps over their lifetime, versus the refrigerant tonnage. I know with my reverse-cycle air-con units the lower electricity usage is a big saving compared with using old-fashioned electric heaters, but how well that works in colder climates is another question. It's all very interesting stuff.