Technology [alternatives to traditional roof a/c units]

Topic: Technology [alternatives to traditional roof a/c units] (Read 1162 times) previous topic - next topic

Technology [alternatives to traditional roof a/c units]

August 11, 2017, 11:32:45 pm

Can we have a 13,500 btuh coach air conditioning system that uses less than 900 watts and will start on a 1000 watt invertor. You bet. You could run it while traveling, off of the Engine alternator, or a hybrid inverter. You could run it off of 15 amp circuit and plug-in cord. You may be able to boondock all night after you shut down the genset. You Could you downsize your genset because the starting in rush current or locked rotor amps are within 1 amp of full load current.

This technology has been around for almost ten years and it keeps improving. You can walk into home Depot, and buy this oriental hvac unit.

Newest technology in propeller fans (which we are running horrific efficiency stamped steel fans) has vastly
Improved, the already very efficient composite plastic fans have been improved by adding turbicles, and by preventing end vortex shedding. LG were able to achieve a 10% increase in flow, and a 20% decrease in hp. R&D in America is stuck.

We as coach owners are stuck with crap, until [alternatives] enter the market.

[updated topic title to be more descriptive - minor edit on one phrase based on member complaints - Michelle]

Re: Technology

Reply #1 – August 11, 2017, 11:37:53 pm

Like to have a link to a 13500 btu ac that would run off a 1000 watt inverter.

Re: Technology

Reply #2 – August 11, 2017, 11:58:46 pm

My shoulder just popped back in the socket after going fer the Big Dictionario to look up: Turbicles

You learn something new every 24 to 46 hours, doncha? I'm ok.

Re: Technology

Reply #3 – August 12, 2017, 02:40:32 am

Unfortunately RV air conditioners, are not available this way. Tried to attempt/convience the builders of Coleman RV a/c units to explore this option. I got no response. I have cornered their "engineers" at a restaurant close by me. They seemed very interested but no follow up call.

Re: Technology

Reply #4 – August 12, 2017, 09:00:44 am

If they are so easy to build profitably, go build them.

Re: Technology

Reply #5 – August 12, 2017, 09:18:25 am

Old Phart is obviously talking about ductless mini splits, and having installed several I agree, they are awesome. Head and shoulders above any other form of residential ac for efficiency, low cost, high quality, quietness but with their limitations of placement. AC contractors are often detractors as the equipment lends itself to self installation.

Like many others I have pondered installing one in the coach. I believe a company that wanted to develop retrofits could do well.

Re: Technology

Reply #6 – August 12, 2017, 10:13:42 am

Here's a good article on "tubercles":
Whale of an Idea - Design Engineering
7 year old article. I have never heard of these.
Names can be funny: "...Dr. Frank E. Fish, now WhalePower's president." What are the chances??

Re: Technology

Reply #7 – August 12, 2017, 10:33:38 am

Quote from: sedelange – August 12, 2017, 09:00:44 am

If they are so easy to build profitably, go build them.

I intend to attempt to build one this winter, to fit the standard roof opening. Profitable I doubt, at this point since I will be buying a completed unit and disassemble it to gain access to the inverter compressor, complex control boards, ecm fan motors, and electronic expansion valve. Airxcel is just mile down the road from me, maybe then they may wake up if I showed it to them.
America has forgotten about R&D and wonders what happened as their market share shrinks or disappears entirely.

Re: Technology

Reply #8 – August 12, 2017, 10:37:59 am

Are you going to use ceiling cassette style evaps?

Re: Technology

Reply #9 – August 12, 2017, 10:45:50 am

Modified mini-split systems [basement air] have been installed in coaches for 40 years or so [Prevost, Newell etc].
The compressor/condenser takes up a lot of room under the coach and because of the fan it needs, produces noise at ground level.
A motor home would require several zones or several units or an elaborate ducting system. The mini splits big enough to cool a motor home all require 220 volt service available on bus conversions and high end coaches, but not on most cheaper coaches.
The industry likes the roof top because they are cheap, easy to replace [they are throwaway] and do not take up any basement room.
A lot of the recent Newell's and bus conversions are being ordered from the factory with 3 or 4 or even 5 roof units because of the problems with basement air.

Re: Technology

Reply #10 – August 12, 2017, 11:25:25 am

Quote from: jcus – August 12, 2017, 10:45:50 am

A lot of the recent Newell's and bus conversions are being ordered from the factory with 3 or 4 or even 5 roof units because of the problems with basement air.

Thanks for the explanation, I'd wondered why I'd seen so many high liners lately with lotsa roof units!

Re: Technology

Reply #11 – August 12, 2017, 12:23:06 pm

Quote from: Chuck Pearson – August 12, 2017, 10:37:59 am

Are you going to use ceiling cassette style evaps?

I was looking into ceiling cassette units to retrofit my ACs but a couple of problems exist.

1. The dimensions of the ceiling cassettes are much larger than the standard 14x14 rooftop air opening. They are designed to fit into a standard 24x24 opening in a drop ceiling typical in a commercial building.
2. Ceiling cassettes are a minimum of 7" tall which would mean it would need some sort of weatherproof cover built over it on the roof.

I have pretty much given up on the ceiling cassette units and am looking at floor console units which mount low enough on the wall that it would fit underneath our windows.

Re: Technology

Reply #12 – August 12, 2017, 12:25:30 pm

I would get roof airs instead of basement air in a prevost and I would never get 4 slides so I could get over the road air as well.

Re: Technology

Reply #13 – August 12, 2017, 12:36:10 pm

1996 U270 Dual Central Air Conditioning

Re: Technology

Reply #14 – August 12, 2017, 01:13:52 pm

Quote from: rsihnhold – August 12, 2017, 12:23:06 pm

I was looking into ceiling cassette units to retrofit my ACs but a couple of problems exist.

1. The dimensions of the ceiling cassettes are much larger than the standard 14x14 rooftop air opening. They are designed to fit into a standard 24x24 opening in a drop ceiling typical in a commercial building.
2. Ceiling cassettes are a minimum of 7" tall which would mean it would need some sort of weatherproof cover built over it on the roof.

I have pretty much given up on the ceiling cassette units and am looking at floor console units which mount low enough on the wall that it would fit underneath our windows.

I am going to try the existing 14x14 holes, I believe it will take 2 evaporator coils and 2 condenser coils per unit to get the efficiency, so the roof unit shroud will grow longer and have to be fabricated. So two dead or used donor roof units per system. Or slice up the mini's coil and reconfigure it and resolder.

I would consider a multizone mini but where would you mount the condensing unit, and they require 220 power which would require a boost transformer. 220 power units are however available in higher EER. SEER ratings are horse poo generated by the marketing department, and adding majic factors, or omitting essential filters etc.

Re: Technology

Reply #15 – August 12, 2017, 01:28:42 pm

Quote from: Old phart phred – August 12, 2017, 01:13:52 pm

I am going to try the existing 14x14 holes, I believe it will take 2 evaporator coils and 2 condenser coils per unit to get the efficiency, so the roof unit shroud will grow longer and have to be fabricated. So two dead or used donor roof units per system. Or slice up the mini's coil and reconfigure it and resolder.

I would consider a multizone mini but where would you mount the condensing unit, and they require 220 power which would require a boost transformer. 220 power units are however available in higher EER. SEER ratings are horse poo generated by the marketing department, and adding majic factors, or omitting essential filters etc.

Where will you put the compressor/condenser units?

Re: Technology

Reply #16 – August 12, 2017, 01:37:58 pm

Quote from: Old phart phred – August 12, 2017, 01:13:52 pm

I am going to try the existing 14x14 holes, I believe it will take 2 evaporator coils and 2 condenser coils per unit to get the efficiency, so the roof unit shroud will grow longer and have to be fabricated. So two dead or used donor roof units per system. Or slice up the mini's coil and reconfigure it and resolder.

I would consider a multizone mini but where would you mount the condensing unit, and they require 220 power which would require a boost transformer. 220 power units are however available in higher EER. SEER ratings are horse poo generated by the marketing department, and adding majic factors, or omitting essential filters etc.

I initially considered a transformer but have since decided to use a 240 volt inverter. You can use a cheaper option like this 4000 watt AIMS unit or you can go the more expensive route by using two5000 watt 12v Victron Quattro units to create split phase 240v to power the mini split (probably could get by with the cheaper 3000 watt Victron Multi units also since inverter mini splits don't have the large start up current that non-inverter units have).

I would mount the condensing unit behind the driver's side rear tire that is currently occupied by my engine's air filter which would be moved to the rear engine bay opening like some Foretravels originally were set up. The small space requirements will limit the choices available in a multi-zone condensing unit though.

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Re: Technology

Reply #17 – August 12, 2017, 01:39:07 pm

In the extended fabricated roof shroud, coils in a vee arrangement top discharge.

Re: Technology

Reply #18 – August 12, 2017, 01:41:13 pm

The Aussies (AirCommand available in the US) Atwood looks like it has some of the features you require, mainly improved 3 stage air flow 330 CFM @ 66dB. It only requires 11.3 Amps / 1270 Watts ,BUT states needs 2000 watts starting (maybe less?). They also have many different technologies to choose.

Maybe MR B2 can chime in 'bout how much better he has it living "Down Under"

Dan

Re: Technology

Reply #19 – August 12, 2017, 01:46:13 pm

Coleman power saver 13.5 runs on 11.2amps and will start on most 2kw invertor generators

Re: Technology

Reply #20 – August 12, 2017, 01:48:23 pm

Quote from: rsihnhold – August 12, 2017, 01:37:58 pm

I initially considered a transformer but have since decided to use a 240 volt inverter. You can use a cheaper option like this 4000 watt AIMS unit or you can go the more expensive route by using two5000 watt 12v Victron Quattro units to create split phase 240v to power the mini split (probably could get by with the cheaper 3000 watt Victron Multi units also since inverter mini splits don't have the large start up current that non-inverter units have).

I would mount the condensing unit behind the driver's side rear tire that is currently occupied by my engine's air filter which would be moved to the rear engine bay opening like some Foretravels originally were set up. The small space requirements will limit the choices available in a multi-zone condensing unit though.

Removing the big muffler and replacing with a resonator will give you a lot of room behind the drivers side rear wheel.

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Technology

Reply #21 – August 12, 2017, 01:52:21 pm

Quote from: Old phart phred – August 12, 2017, 01:39:07 pm

In the extended fabricated roof shroud, coils in a vee arrangement top discharge.

So basically a more efficient rooftop unit?

Re: Technology

Reply #22 – August 12, 2017, 01:59:12 pm

Quote from: jcus – August 12, 2017, 01:52:21 pm

So basically a more efficient rooftop unit?

Yes, but after reading how much Jerry spent I may rethink. But then again it sounds like a fun project, and I can hide out in the garage all winter:)

Re: Technology

Reply #23 – August 12, 2017, 04:57:57 pm

The Dometic brochure I attached lists two split systems available for RV's. Would need a 240V/50 hz dedicated invertor.
Dometic aircommand heron 2.2 | Dometic - Mobile living made easy.

They ran around $1200. Can't guarantee they will ship to US.

Re: Technology

Reply #24 – August 12, 2017, 05:12:42 pm

Amazing that the inverter compressor takes AC single phase power, converts to DC power, and then converts back to achieve ac multiphase power to run the motor. Samsung's new compressor operates on six phase power IRC

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