Air Com

[Adethefridge]

You're quite right
I just meant there is a very easy solution for a/c systems with the discharge above the water line...

 

[Portofino]

Yup. All comes down to choices and compromises, as ever. If you have space and budget you're better arguably with 2x 9 rather than 1x16, then those problems wouldn't stop you in a holiday. But dims of a 9 are virtually same as a 16 and you have to find space. I have 2x 60 compressors rather than 1x 120, and one has failed in the past, and the dual install allowed the show to go on. But as I say you have to make choices and compromises then hope you made the right choice

For Pete's boat it would be interesting to see whether a single 9k btu/hr unit that is inverter driven (like Portofino-itama's) could be run off a big inverter, possibly at 2/3rds output, during navigation

We have a 42 btu unit and it's silent .
Frigomar
Cost € 18 K
Others like " selfie S came in @ circa €12 K about €4 K / space fitted inc tax

Just driven down from Switzerland in the Bentley Gt some times 3 figure speeds to find a bottle of rose and
The boat the boat ( guaerdiene ) turn the fridge / AC on
Was 34 in IT

It makes a big diff the quality of A/ C -- with it
Do not scrimp Pete
And rose

 

[MapisM]

You're quite right
I just meant there is a very easy solution for a/c systems with the discharge above the water line...

Understood, sorry for the sarcastic comment, I was just following my train of thoughts...! :encouragement:
Anyhow, an easy and inexpensive fix it is for sure, but depending on the boat and the outlet position it might be a bit annoying in terms of accessibility, I suppose...

 

[petem]

Others will have an opposing view on this but I'd recommend having the raw water outlet just below the waterline, to prevent annoyance to neighbours at night.

Indeed that was the advice proffered by the guys that I spoke to this afternoon.

 

[petem]

And rose

Sorry, with a boat called Andiamo it's got to be Prosecco. Or better still Moretti.

 

[Adethefridge]

I'd check which refrigerant your new system is running on , & your happy with how long it will be available for as
Most refrigerants used today are being phased out some as early as 2025

 

[vas]

interesting discussion re back pressure.
I'm about to reconnect the aircon following the rebuilt, don't even remember where the outlet was, what I do know is that both inlet and outlet are now 60cm below waterline.
Bearing in mind the raw water circ pump is in a very sorry state, what sort of pump am I meant to buy for this task? Are there specific specs on throughput and output at -0.6 head?
Now idea how big the unit is in btu, guess 16K

cheers

V.

 

[jimmy_the_builder]

interesting discussion re back pressure.
I'm about to reconnect the aircon following the rebuilt, don't even remember where the outlet was, what I do know is that both inlet and outlet are now 60cm below waterline.
Bearing in mind the raw water circ pump is in a very sorry state, what sort of pump am I meant to buy for this task? Are there specific specs on throughput and output at -0.6 head?
Now idea how big the unit is in btu, guess 16K

cheers

V.

If the inlet and outlet are at the same depth below waterline - isn't it a zero sum for the pump in terms of back pressure?

 

[vas]

If the inlet and outlet are at the same depth below waterline - isn't it a zero sum for the pump in terms of back pressure?

would make sense, but then all the previous posters discussing backpressure would be wrong as in such cases I'd expect inlet to bo lower than outlet, so would have a negative backpressure

let's see what the experts have to say!

cheers

V.

 

[PowerYachtBlog]

Why 16k?. My Gobbi 335 SC which has a bigger interior then the 34 Targa needs 8k for the saloon forward cabin, and 4k for the midships cabin.

 

[petem]

Why 16k?. My Gobbi 335 SC which has a bigger interior then the 34 Targa needs 8k for the saloon forward cabin, and 4k for the midships cabin.

W, I'm not bothered about cooling the aft cabin but I did wonder if 12k might be sufficient to cool the forward cabin and the saloon. JTB quoted 16k for his T40 which is quite a big bigger than my boat which might support this theory.

I did read somewhere that too high a capacity can actually be a negative.

 

[superheat6k]

I started here to write a method of converting a small office /domestic split style AC system, but the killer is going to be the conversion work including buying / fitting a seawater compatible cooled condenser.

I couldn't keep the price (to me) below £4,000 for something that would be an experiment. Commercially I couldn't quote such a job for less than £6,000 and this doesn't allow much if anything for the commercial risk factor (warranty, risk, etc) that must also be factored in. By now a small chilled water system is appearing.

Worth while looking at Heron hill for small water cooled AC kit assuming you have worked out what will provide the chilled water (my chiller units are a little too large for this ~ 100 - 1500 kW). 16,000 BTUs/hr ~ 4.5 kW.

On the subject to refrigerants we have now seen the 7th consecutive month of prices rises between 10 - 20% each month R134a and 20 - 50% each month R410A. R407C sits between these two. The actual rise in R134a (which is what my business uses most of) is now 140% up since February. Not only this, but our major supplier cannot supply certain grades at all for the rest of this year, and this is before a 30% reduction in market volume from 2018 affecting all HFCs. They reckon the higher they push their prices the more they are selling !

No AC use HFCs below GWP 2,500 are being banned, they are simply being priced out of the market by an EU wide quantity limit based upon the equivalent CO2 tonnage of the specific refrigerant. This is an extremely complicated method of determining refrigerant environmental harm based upon the equivalent CO2 tonnage per kg.

What they (the EU Directive that is) haven't explained too loudly is that the HFO family of gases that will replace HFCs are generally at least moderately flammable, as are Hydro Carbon gases that have been around in smaller fridges for around a decade. If anyone tells you HC fridges don't catch fire - Grenfell Tower fire started in an HC fridge.

Boats are made of flammable plastic and carry lots of fuel and soft furnishings. Not sure I would want a fridge on fire onboard my boat !

 

[jimmy_the_builder]

W, I'm not bothered about cooling the aft cabin but I did wonder if 12k might be sufficient to cool the forward cabin and the saloon. JTB quoted 16k for his T40 which is quite a big bigger than my boat which might support this theory.

I did read somewhere that too high a capacity can actually be a negative.

Yep, just to clarify, the 16K on my T40 is for the front cabin and saloon only. Doesn't (and not designed to) cool the mid cabin.

 

[petem]

Thanks, I'm not fussed about cooling the aft cabin. Your boat must have at least 30% more volume in the forward cabin and saloon than mine.

 

[jimmy_the_builder]

Thanks, I'm not fussed about cooling the aft cabin.

Fair enough, although what I would say is that while it has been absolutely fine for the two of us, it's not much fun for guests (assuming you accommodate your guests in your aft cabin Pete...), and tbh if I was doing it again I would provide for the whole boat. Also - won't your syndicate partners have a view about the aircon?

 

[Adethefridge]

when I started using hoses to discharge below sea level I was concerned about putting a back pressure on the pumps ,
my logic was discharging water to air has far less resistance than discharging water through water regardless of depth ,how far can you spit under water ?
When I measured the difference in current drawn by the pumps it was in fact greater but only by a small amount and well within the full load current rated by the manufacturer of the pumps , running pressures/ amps drawn by the a/c units didn't change
Happy days...
We have 12k on our T37 copes well in the med , having said that it does take a few hours to pull down to temp

 

[Adethefridge]

I started here to write a method of converting a small office /domestic split style AC system, but the killer is going to be the conversion work including buying / fitting a seawater compatible cooled condenser.

I couldn't keep the price (to me) below £4,000 for something that would be an experiment. Commercially I couldn't quote such a job for less than £6,000 and this doesn't allow much if anything for the commercial risk factor (warranty, risk, etc) that must also be factored in. By now a small chilled water system is appearing.

Worth while looking at Heron hill for small water cooled AC kit assuming you have worked out what will provide the chilled water (my chiller units are a little too large for this ~ 100 - 1500 kW). 16,000 BTUs/hr ~ 4.5 kW.

On the subject to refrigerants we have now seen the 7th consecutive month of prices rises between 10 - 20% each month R134a and 20 - 50% each month R410A. R407C sits between these two. The actual rise in R134a (which is what my business uses most of) is now 140% up since February. Not only this, but our major supplier cannot supply certain grades at all for the rest of this year, and this is before a 30% reduction in market volume from 2018 affecting all HFCs. They reckon the higher they push their prices the more they are selling !

No AC use HFCs below GWP 2,500 are being banned, they are simply being priced out of the market by an EU wide quantity limit based upon the equivalent CO2 tonnage of the specific refrigerant. This is an extremely complicated method of determining refrigerant environmental harm based upon the equivalent CO2 tonnage per kg.

What they (the EU Directive that is) haven't explained too loudly is that the HFO family of gases that will replace HFCs are generally at least moderately flammable, as are Hydro Carbon gases that have been around in smaller fridges for around a decade. If anyone tells you HC fridges don't catch fire - Grenfell Tower fire started in an HC fridge.

Boats are made of flammable plastic and carry lots of fuel and soft furnishings. Not sure I would want a fridge on fire onboard my boat !

My stumbling bock is taking an inverter compressor,electronic expansion valve, pcb / thermistors etc and marrying them up to a water cooled condenser, I have a few R410 5kw splits in the workshop earmarked for the boat

 

[DavidJ]

Others will have an opposing view on this but I'd recommend having the raw water outlet just below the waterline, to prevent annoyance to neighbours at night.

I use two 12" lengths of plastic hose pushed into the outlets, they terminate just below the waterline
No water noise & no restriction on water pump pressure , just have to remember to remove them before taking the boat out

I converted my outlet this year to a through the bottom of the boat because of disturbing the the neighbours. I don't detect any decrease in performance and it's been really hot in Spain this year.

 

[jrudge]

Pete.

If doing it do it right and do the aft cabin as well.

On my t40 there was a 12k unit under stairs for saloon and aft and a 7k for front cabin.

 

[petem]

Fair enough, although what I would say is that while it has been absolutely fine for the two of us, it's not much fun for guests (assuming you accommodate your guests in your aft cabin Pete...), and tbh if I was doing it again I would provide for the whole boat. Also - won't your syndicate partners have a view about the aircon?

Of course I'll give them the options but the partner who had a T34 before for 5 years didn't have A/C at all and didn't miss it (nuts), the other guy is single and will probably only have guests very rarely.

As well as the cost factor, there's also space to be considered. Storage is already at a premium and a separate a/c ubit for the rear rear cabin would mean the loss of another storage area. I will investigate the option of a unit under the saloon sofa with outlets to the front cabin, saloon and rear cabin.

As ever, it's all about compromises when funds and space are limited.