Self Contained Reverse Cycle Air Conditioning Change Out

It's time to replace one of our AC/Heat units and I'm looking for product recommendations or warnings of problem brands. We need to replace a 24,000 BTU 220V unit and want the most energy efficient quietest unit that is reliable. Any brand user pros or cons would be welcome!

Spottsville said:

It's time to replace one of our AC/Heat units and I'm looking for product recommendations or warnings of problem brands. We need to replace a 24,000 BTU 220V unit and want the most energy efficient quietest unit that is reliable. Any brand user pros or cons would be welcome!

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efficient go for inverter technology this is super nice and now using from long time on building air conditioning so we have good return now.

Frigomar make it but sure you can find other brand

Inverter BLDC - SELF CONTAINED UNIT

Flagship Marine. Conventional reverse cycle air conditioning but the heat side is straight electric furnace. The unit is much more heavily built that the usual suspects. I just sold a boat with a 20 year old (problem free) Flagship system and promptly installed one in my new boat.

Mitsubishi Mini Split

Efficient , VERY efficient at heat ,multiple zones if desired and no seawater required.

101TUG said:

efficient go for inverter technology this is super nice and now using from long time on building air conditioning so we have good return now.



Frigomar make it but sure you can find other brand



Inverter BLDC - SELF CONTAINED UNIT

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I was not aware of this approach to HVAC. Very interesting. A quick Google search did not yield other brands.... I sent an email to Frigomar to see if they sell into US.
Thanks for info!
Norm

boatpoker said:

Flagship Marine. Conventional reverse cycle air conditioning but the heat side is straight electric furnace. The unit is much more heavily built that the usual suspects. I just sold a boat with a 20 year old (problem free) Flagship system and promptly installed one in my new boat.

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Flagship looks to be very well built but I don't know about using straight electric on the heat side. The 24k unit uses 4 kW for heat and 20 amps (ouch). Does have the advantage of no need for warm water to heat so can be used in winter with very cold water although that use is unlikely for me. We do use the heat side occasionally to warm the boat after a cool night to extend our season. The 20 amp draw is a limiting factor...

Thanks
Norm

FF said:

Mitsubishi Mini Split

Efficient , VERY efficient at heat ,multiple zones if desired and no seawater required.

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I can see how the mini split system could be good in some boat applications but for us the outside unit is a show stopper given we have 3 units on our boat and don't want the noise and hot air exhaust on deck.
Thanks
Norm

Norm, I would be looking at split units from Cruisair. The compressor and condenser where they belong in your big engine room. We have a Cruisair split unit 16,000 BTU that was on our Manatee when we bought it 8 years ago and looks to be maybe 1990 vintage still cooling and heating. We also had a Cruisair 16,000 BTU package unit added last year with the compressor sound enclosure added that is very quiet and compact.

"3 units on our boat and don't want the noise and hot air exhaust on deck."

In Europe they simply bolt them to the aft rail.

The Heat output is 3x to 5x what a toaster wire produces per KW.

boatpoker said:

Flagship Marine. Conventional reverse cycle air conditioning but the heat side is straight electric furnace. The unit is much more heavily built that the usual suspects. I just sold a boat with a 20 year old (problem free) Flagship system and promptly installed one in my new boat.

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How is it reverse cycle if the heat is straight electric furnace?

Norm,

We installed Webasto FCF units during our refit. Prices were great, and no complaints to date. Came with wireless remote controls which we don't use. We ran these heavily as liveaboards for one very cold winter and the usual hot and humid summer in Baltimore. Since we left on our extended Caribbean cruise, they are not being used nearly as much, so can't report long term info.

FF said:

"3 units on our boat and don't want the noise and hot air exhaust on deck."

In Europe they simply bolt them to the aft rail.

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That's interesting. Do you have any pictures of that?

How do the run the power and gas lines into the boat?

Capt.Bill11 said:

That's interesting. Do you have any pictures of that?

How do the run the power and gas lines into the boat?

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Oh just drape them along the rails with the carnival lights.

They must look like crap, sorry considering as they are not made for direct salt spray and look like Sanford and Son rejects bolted on to the back rails of a boat and cost near the same as a boat AC does (I have one cooling my garage/shop) no thanks. I don't care that some blokes in EU have no concern for looks, I do.

Hijack warning.

Air conditioning for almost free. This guy is a genius.

Spottsville said:

I was not aware of this approach to HVAC. Very interesting. A quick Google search did not yield other brands.... I sent an email to Frigomar to see if they sell into US.
Thanks for info!
Norm

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we install all ready 3 unit this is totally incredible technology, inverter start slowly the compressor no big A to start like old model

soon I can I'm going to change my chiller by inverter technology to run AC on solar panel.

Hugues

Saw the frigiomar chillers at the Miami boat show and I planned on adding one for underway use only off our house bank. Unfortunately the local distributor wasn't able to get one done on my schedule. Probably buy the unit and install it myself next year as I have already cleared space for it.

If you aren't looking for the new vfd high efficiency tech then the flagship marine gear is tough to beat as well.


Spell check via iPhone.

"I don't care that some blokes in EU have no concern for looks, I do."

That their dockside cost of electric is 3X to 5X what ours is might make them less concerned with the "Look".

This inverter tech IS the wave of the future ,when the boat assemblers learn to build it in , we will all delight in less power use, from the dock or the noisemaker.

BobH said:

How is it reverse cycle if the heat is straight electric furnace?

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The air conditioning side is reverse cycle. i.e. exchanges heat through the water.

SCOTTEDAVIS said:

Oh just drape them along the rails with the carnival lights.

They must look like crap, sorry considering as they are not made for direct salt spray and look like Sanford and Son rejects bolted on to the back rails of a boat and cost near the same as a boat AC does (I have one cooling my garage/shop) no thanks. I don't care that some blokes in EU have no concern for looks, I do.

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Of course you do Scottie, you have a beautiful boat.

Most water sourced reverse cycle heat fails to work when the water is about 40F.

The source water with heat removed freezes ,so a heater element is required .

Few folks get to 40F water so the inefficiency of the reverse cycle units is accepted.

Especially at a marina with "free " electric.

In the deep south most air cond is just air cond with no reverse cycle plumbing.

This is because the added plumbing reduces the air cond efficiency (which may be a 9 or 10 month requirement) enough that heating only a small percentage of the time is cheaper with a heat strip on a year long basis.

FF said:

In the deep south most air cond is just air cond with no reverse cycle plumbing.

This is because the added plumbing reduces the air cond efficiency (which may be a 9 or 10 month requirement) enough that heating only a small percentage of the time is cheaper with a heat strip on a year long basis.

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True and perhaps not at any added cost at all.

The owner and engineer at Ocean Breeze told me that the heat pump side really does not save over the strip heating option they sell (no difference in price). The units are designed to be a drop in replacement for all boat units and therefor he did not want any required electrical changes. He further stated that the reversing valve is a source of trouble and needs to be exercised several times a year and reduces the AC cooling efficiency by approximately 15%. The units will not provide enough heat to live aboard in the cold north winters but neither would reverse cycle units.

The nice thing about heat strips is that you are only using the unit fan and resistance strip so you can close the sea valve in the winter and water temp. does not change the heat output of the unit. The only sound from the units is the fan running as the compressor gets the season off (lasting longer) you can even have heat on the hard given the proper power.

The breaker size remains the same as it was explained to me that the energy requirements are both nearly the same.

For my use (here in the USA) and my needs, I have straight cool with heat strips. I installed 2 Ocean Breeze 16,800 BTU units and both run and cool well here in Florida during the hottest months and will both work with my 7K noisemaker with power left over to run the water heater.

Ocean Breeze uses only over the counter parts, relays, fans and compressors that can be purchased at any good AC supply house. No computer boards or fancy t-stats, in fact I used t-stats from Home Depot and one unit I can control from my smart phone using the internet.

boatpoker said:

The air conditioning side is reverse cycle. i.e. exchanges heat through the water.

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I thought "reverse cycle" meant you could get cool (AC) or heat out of a single unit.

I thought some marine ACs are not "reverse cycle" -- maybe that Flagship thing? -- and use a resistance solution (not raw water flow) to produce heat.

???


FWIW, a live-aboard boat neighbor had a new reverse cycle AC unit installed last year -- Dometic Vector Turbo -- and also had a resistance heat source added to that... so when outside water temps got too low or surrounding water even froze, they still had heat using the Vector Turbo blower fans and the same ducting system.


-Chris

"they still had heat using the Vector Turbo blower fans and the same ducting system.

And the heat cost 3 to 5 times the electricity of the Air Mini split style units.

If electric is "Free", that's fine , at 25c a KW it can add up in a winter aboard.

If resistance heat is used aboard the simplest style oil filled heaters do an OK job and are far more reliable than diesel fed truck and bus heaters repurposed for boat use.

FF said:

"they still had heat using the Vector Turbo blower fans and the same ducting system.

And the heat cost 3 to 5 times the electricity of the Air Mini split style units.

If electric is "Free", that's fine , at 25c a KW it can add up in a winter aboard.

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Yeah, but at least they knew what to expect, they needed a new reverse cycle AC anyway, and had the heating element all done at the same time because it was the easiest physical solution for that particular boat.

And they were on metered electric service (we all pay our own directly to the local utility), so they knew it was their dime.

It wasn't intended to be used all that often, just when the reverse cycle system couldn't draw enough heat from sea water. Like when the marina was frozen in.

I think I said they did it last year, but I mis-typed. It was the previous year, and it got them through the 2014/15 winter. Then this last winter, they took the boat south for the inter, NC or GA or somewhere like that. Maybe used their savings in electricity money to pay for the trip.

-Chris

101TUG said:

we install all ready 3 unit this is totally incredible technology, inverter start slowly the compressor no big A to start like old model



soon I can I'm going to change my chiller by inverter technology to run AC on solar panel.



Hugues

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Where do you buy your units? I have contacted a dealer in Fort Lauderdale but they are not providing a deliver price and I'm leary of them now.

Norm

Spottsville said:

Where do you buy your units? I have contacted a dealer in Fort Lauderdale but they are not providing a deliver price and I'm leary of them now.

Norm

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I think all of the air-cooled mini split systems I'm looking at use inverter technology.

SCOTTEDAVIS said:

The owner and engineer at Ocean Breeze told me that the heat pump side really does not save over the strip heating option they sell (no difference in price). He further stated that the reversing valve is a source of trouble and needs to be exercised several times a year and reduces the AC cooling efficiency by approximately 15%.

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HE LIED!

45+ years in HVAC I've never not seen or known a Rev Valve to fail. Many techs thought "bad Rev Valve" but it was usually relays or low refrigerant.

When in the heat cycle the compressor draws even less amps then when in the cooling cycle.

A 5 KW strip heater for example. can draw 20 amps on 240 volts

the strip heaters on Marine units have to be small enough to run on even less amps which means very small strip heaters.

compressor load of around 16,000 btu will draw less then 8 amps. you don't have to believe me, check the name plates and published ratings of the machines.

nearly all units are what ypeople think is "soft start" it's just how they
work.

I don't think any MFG uses the old reciprocating compressors anymore. Most if not all use "rotary or scroll" compressors.



Inverter tech is here to stay and taken a big foothold in the HVAC business.

Just one more note. Marine acs are not strange or unique. they are simple self contained water cooled units.

This what makes them "water cooled" It's called a "coaxial" heat exchanger. (tube in tube)

So basically the tube in a tube allows the condenser heat to be recovered and used when heating is needed? Do both condenser and evaporator sides go through those coaxial heat exchangers in marine chillers?

In heating cycle the heat ex actually becomes the evap and the evap becomes the condenser, large systems like high-rise blogs and possibly ships can use a closed or open loop with many units giving and taking heat from the water

Just curious...the 16K btu Webasto lists .....

http://www.defender.com/product.jsp?path=-1|2276179|2061076|2061077|2061083&id=3050539

Specifications:

Voltage: 115 Volts AC or 230 Volts ACCooling Capacity: 16,000 BTU/hHeating Capacity: 16,000 BTU/hRated Frequency:115 Volts AC = 60Hz230 Volts AC = 50/60HzRated Current (C/H):115 Volts AC = 11.2/12 Amp230 Volts AC = 5.6/5.6 AmpRefrigerant Charge: R410A (0.5kg)Comp. LRA:

Their running amps is up near what mine is ...they list 11. 2 cooling and 12 heating.....mine is 10.8 and a touch higher for heatingon my Marinaire unit.

My manual also says to switch from a/c to heat or vice versa every month to keep the reversing valve operational.

Curious your thoughts?