More design ideas/questions
- Thread starter Mickldo
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whatcharterboat
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Far out Mick. I've been away for a week too and this thread's just plain exploded. BTW what's that yellow rig in the corner?
Have you seen the DCAirco units? Not cheap but are used on some new sleeper cab trucks here. They were also developed for cooling satellite communication equipment in remote areas using only solar power. They are a split system and normally mounted on the rear of a cab with the evapoarator fans inside. IIRC they come pregassed and have about 2.4 metres of interconnecting hoses. Call me if you want the reps contact in Brisvegas.
About the hybrid/lazy axle. I know Lexus are doing it with a 4wd now, so it would be interesting to sus that out. Also have a look at the Canter-based Eco-D Concept as well as the 2WD Hino. Only a concept but some great ideas. Saw a 10ton Hino 4x4 tour bus in Melbourne last week BTW. They must be very similar to the FSS 550 Isuzu.
We were involved with a project at work awhile ago developing a 4WD, 4WS vehicle with 4 hub motors. Very cool software controlling the direction and speed of each wheel as it cornered. Super efficient as far as transmission losses go. It could even crab sideways to park in a tight spot. If you seriously consider a hybrid drive, look at regenerative braking. This will further improve your efficiency.
Also I did a paper on "Alternative Transport" as part of some early qualifications in Renewable Energy Technology about 10 years ago, and I seem to remember researching a hybrid Hummer that was also driven with 4 hub motors and powered by a diesel genset charging a battery bank. It could obviously go into stealth mode/silent running and reduce its heat signature. Not that you would be worried about that but the hub motors were awesome for ground clearance. Don't know if it ever went into production.
BTW You coming down next weekend for the Noosa hillclimb?
Far out Mick. I've been away for a week too and this thread's just plain exploded. BTW what's that yellow rig in the corner?
Have you seen the DCAirco units? Not cheap but are used on some new sleeper cab trucks here. They were also developed for cooling satellite communication equipment in remote areas using only solar power. They are a split system and normally mounted on the rear of a cab with the evapoarator fans inside. IIRC they come pregassed and have about 2.4 metres of interconnecting hoses. Call me if you want the reps contact in Brisvegas.
About the hybrid/lazy axle. I know Lexus are doing it with a 4wd now, so it would be interesting to sus that out. Also have a look at the Canter-based Eco-D Concept as well as the 2WD Hino. Only a concept but some great ideas. Saw a 10ton Hino 4x4 tour bus in Melbourne last week BTW. They must be very similar to the FSS 550 Isuzu.
We were involved with a project at work awhile ago developing a 4WD, 4WS vehicle with 4 hub motors. Very cool software controlling the direction and speed of each wheel as it cornered. Super efficient as far as transmission losses go. It could even crab sideways to park in a tight spot. If you seriously consider a hybrid drive, look at regenerative braking. This will further improve your efficiency.
Also I did a paper on "Alternative Transport" as part of some early qualifications in Renewable Energy Technology about 10 years ago, and I seem to remember researching a hybrid Hummer that was also driven with 4 hub motors and powered by a diesel genset charging a battery bank. It could obviously go into stealth mode/silent running and reduce its heat signature. Not that you would be worried about that but the hub motors were awesome for ground clearance. Don't know if it ever went into production.
BTW You coming down next weekend for the Noosa hillclimb?
whatcharterboat
Supporting Sponsor, Overland Certified OC0018
A hybrid 4x4 that is, not the lazy axle.
Mickldo said:
I've thought along the same lines. http://www.masterflux.com/ has DC powered compressors of various sizes and input voltages. Looks like Danfoss now has specs online: http://compressors.danfoss.com/products/products_dc/r134a_12-24v_dc/index.htm
Mickldo
Adventurer
whatcharterboat said:Far out Mick. I've been away for a week too and this thread's just plain exploded. BTW what's that yellow rig in the corner?
Have you seen the DCAirco units? Not cheap but are used on some new sleeper cab trucks here. They were also developed for cooling satellite communication equipment in remote areas using only solar power. They are a split system and normally mounted on the rear of a cab with the evapoarator fans inside. IIRC they come pregassed and have about 2.4 metres of interconnecting hoses. Call me if you want the reps contact in Brisvegas.
About the hybrid/lazy axle. I know Lexus are doing it with a 4wd now, so it would be interesting to sus that out. Also have a look at the Canter-based Eco-D Concept as well as the 2WD Hino. Only a concept but some great ideas. Saw a 10ton Hino 4x4 tour bus in Melbourne last week BTW. They must be very similar to the FSS 550 Isuzu.
We were involved with a project at work awhile ago developing a 4WD, 4WS vehicle with 4 hub motors. Very cool software controlling the direction and speed of each wheel as it cornered. Super efficient as far as transmission losses go. It could even crab sideways to park in a tight spot. If you seriously consider a hybrid drive, look at regenerative braking. This will further improve your efficiency.
Also I did a paper on "Alternative Transport" as part of some early qualifications in Renewable Energy Technology about 10 years ago, and I seem to remember researching a hybrid Hummer that was also driven with 4 hub motors and powered by a diesel genset charging a battery bank. It could obviously go into stealth mode/silent running and reduce its heat signature. Not that you would be worried about that but the hub motors were awesome for ground clearance. Don't know if it ever went into production.
BTW You coming down next weekend for the Noosa hillclimb?
That yellow thing in the corner is a HPV we built for the boss's son. Chrome moly framed three wheeled recumbent trike. They race it in the Maryborough Technology Challenge. They race it for 24hrs around the school and whichever team does the most laps wins. They won the first year and have come second the past two years.
If you could PM me the reps details for that AC stuff it would be great.
I'll have to google the Lexus Hybrid. Interesting.
I'd love to build something with the hub motors but I reckon this one I'd like to keep as stock as possible (if that is possible with a hybrid
) so I would like to keep the stock rear axle and just add the electric motor to the diff area.I'll PM or ring you about the Hillclimb, I've got an engagement party Sat night so I am not sure if I will come down on Sat or Sun.
RParts has some info online including a forum for supporting their gear. They also sell a book on refrigeration systems. To bad they don't sell the newer large BD series compressors. I've thought that plumbing in a 350 in place of the engine A/C compressor. That would do the cab while driving. For the rear I'd have another one as part of the heating/cooling/air filtration system.Mickldo said:
Mickldo
Adventurer
Bogo said:
I had to call Seabreeze Industries today about a fridge for work. While chatting to the salesman I mentioned we built boats too. He asked if we were interested in AC for boats as they were agents for Cruisair air conditioning. He has sent me through all the tech info on them and he might give us a good deal on one for the new demo boat we are starting soon.
whatcharterboat
Supporting Sponsor, Overland Certified OC0018
Hi Mick. The Cruisair "DC Cuddy" looks to be far more flexible/applicable/adaptable than the DCAirco I mentioned. We had one in here yesterday on the back of a semi we repaired. After looking at it again I think it would just be too big for you.
The only other unit that I've seen here that might be suitable is the little roof top Waeco unit. But hey, the Cruisair sure looks great if the power consumption is OK.
John
The only other unit that I've seen here that might be suitable is the little roof top Waeco unit. But hey, the Cruisair sure looks great if the power consumption is OK.
John
Mickldo
Adventurer
whatcharterboat said:
The DC Cuddy looks good so far but it looks like it is designed to be sea water cooled. I wonder if it would be possible to plumb it into the water tank like we were discussing with the fridge?
From the specs on http://www.cruisair.com/sheets/L-2425D.pdf it draws 29Amps but I don't know what its duty cycle would be. I suppose that it would depend on the size of the room and the temp, amount of insulation, etc.
Interesting. Cruisair is part of Dometic. Dometic is a major maker of RV equipment including air conditioners and other appliances.
Stuff to ponder...
http://www.cruisair.com/sheets/L-2425D.pdf
Reading the specs on it it sounds like it runs off of 120VAC* generated from 12VDC. That hits efficiency right there. Also it requires water to dump the heat to. That is not an option for me.
* In the brochure they talk about being able to substitute in other inverters which leads me to think it is running at 120VAC. Dometic being US it is likely 120VAC but who knows.
A roof top DC Airco 4400 series unit uses only 30A @ 12VDC for 4400 BTUs cooling capacity. http://www.dcairco.com/DC4400.html Their 9000 BTU rooftop unit uses 50A @ 12VDC. http://www.dcairco.com/DC9000.html
Side by side info for the DC Airco units: http://www.dcairco.com/TRUCK-ENG.pdf The brochure even shows an off road RV with one on it.
If the split unit had longer hoses I'd consider it. I'd make my own enclosure at the back for the outside unit, and plumb the head to the front just behind the cab. As is I'm thinking of using the 9000 BTU unit as it will should have less than half the run time of the 4400 BTU unit and it uses only 81% of the energy used by the smaller 4400 BTU unit per BTU pumped. FYI: The DC Airco 9000 BTU unit uses 67% of the energy of the Cruisair 3500 BTU unit per BTU pumped. The only down side is you need batteries that can source higher current loads. That is a minor issue considering it is only 50 Amps versus 30 or 29 Amps for the smaller units.
Stuff to ponder...
http://www.cruisair.com/sheets/L-2425D.pdf
Reading the specs on it it sounds like it runs off of 120VAC* generated from 12VDC. That hits efficiency right there. Also it requires water to dump the heat to. That is not an option for me.
* In the brochure they talk about being able to substitute in other inverters which leads me to think it is running at 120VAC. Dometic being US it is likely 120VAC but who knows.
A roof top DC Airco 4400 series unit uses only 30A @ 12VDC for 4400 BTUs cooling capacity. http://www.dcairco.com/DC4400.html Their 9000 BTU rooftop unit uses 50A @ 12VDC. http://www.dcairco.com/DC9000.html
Side by side info for the DC Airco units: http://www.dcairco.com/TRUCK-ENG.pdf The brochure even shows an off road RV with one on it.
If the split unit had longer hoses I'd consider it. I'd make my own enclosure at the back for the outside unit, and plumb the head to the front just behind the cab. As is I'm thinking of using the 9000 BTU unit as it will should have less than half the run time of the 4400 BTU unit and it uses only 81% of the energy used by the smaller 4400 BTU unit per BTU pumped. FYI: The DC Airco 9000 BTU unit uses 67% of the energy of the Cruisair 3500 BTU unit per BTU pumped. The only down side is you need batteries that can source higher current loads. That is a minor issue considering it is only 50 Amps versus 30 or 29 Amps for the smaller units.
Just how much heat can be dumped into the water tank before the water boils or it is just to hot to dump any more? That's why I don't feel it is feasible for vehicle air conditioner use, vehicle refrigeration use for short durations is a possibility, but please run the numbers... Sure it is more efficient when the water is cool or mildly warm, but what about after tens of thousands of BTUs have been dumped into it? What about when the water supply is running low? For boats this isn't an issue as the water is drawn from and dumped overboard. The RV is self contained with a finite supply of water.Mickldo said:
For some numbers. Lets assume a 50 gallon (189 liter) tank of water that is full. It starts at 70F. For a 50F temperature rise it can only absorb 20,000 BTUs without radiating that heat somewhere. Some heat will leave the tank, but how much? Where will it go? Most water tanks are tucked under the chassis somewhere. Think about it.
In my mind it would be better to have larger coils so the refrigerant flow rate through them is slower and the refrigerant has more time to loose it's heat before being cycled again.
whatcharterboat said:
Waeco truck solutions: http://www.waeco.com/en/Stationary air conditioners for trucks.php
DC operation yet use an integrated inverter to power the compressor, 800W heat pumping capacity, roof and split mounted units. I haven't found how much power they use.
Some Waeco products also look to be handled by Dometic. It doesn't read as a buyout. http://www.dometic.com/enus/Americas/USA/Marine-Air-News/WAECO-Products-become-Dometic/
http://www.dometic.com/enus/Americas/USA/Marine/Refrigerators/Refrigeration/?productdataid=74663 is a small air/water cooled unit for refrigeration. I haven't yet found one sized large enough to air conditioning.
Dometic Truck
http://www.dometic.com/enus/Americas/USA/Truck/HVAC-Solutions/Battery-Powered-HVAC-Guide/
They use a 115VAC inverter to power the air conditioner. Their system includes a 2000W inverter/charger they have cleared as safe for their compressors. Cooling capacities of 7,000 and 10,000 BTUs. Both self contained and split units. They have some interesting notes on use. http://www.dometic.com/enus/America...ery-Powered-HVAC-Guide/Specifying-The-System/ On the other hand power use confuses me as they don't tell voltage to go with the Amps. If Amps is at the battery and 12V it is massivly better than the others. At 24VDC it is still better. On the other hand if it is at 115VAC then it is poor. The amount of batteries they spec makes me think it is poor. 4 group 31 AGM batteries has a useful capacity of around 320Ahours at a 50A draw (4 * 100Ahours * 80%). That gives their unit a draw of around 62Amps for the 7000 BTU unit. On the other hand, what voltage are they cutting it off at? They say the system won't drop it to low to start the truck so what percentage of the batteries are they really using? 80% is a good rule of thumb max depth of discharge for most deep cycle batteries. If they are only dropping to 60% then things look much better but it still isn't as good as the DC Airco direct DC powered units.
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dhackney
Expedition Leader
AirCon
I did a lot of research on 12VDC air conditioning back when I hoped to build a boat, and then a vehicle, that was 12/24VDC only.
The links for what I found are here: http://www.hackneys.com/mitsu/index-resources.htm
Scroll down for the Air Conditioning section.
There are 22 links for AirCon suppliers.
My favorite 12VDC AirCon solution was always Glacier Bay's DCBreeze. At the time I was doing the vehicle research (2006), they did not have their vehicle (non-marine) unit in production yet.
All the truck systems with any reasonable capacity that I was able to find all used inverters and 120VAC compressors.
I did a lot of research on 12VDC air conditioning back when I hoped to build a boat, and then a vehicle, that was 12/24VDC only.
The links for what I found are here: http://www.hackneys.com/mitsu/index-resources.htm
Scroll down for the Air Conditioning section.
There are 22 links for AirCon suppliers.
My favorite 12VDC AirCon solution was always Glacier Bay's DCBreeze. At the time I was doing the vehicle research (2006), they did not have their vehicle (non-marine) unit in production yet.
All the truck systems with any reasonable capacity that I was able to find all used inverters and 120VAC compressors.
dhackney
Expedition Leader
Bogo said:
Discharging deep cycle batteries, such as AGMs, lower than 50% on a consistent basis will dramatically shorten the service life of the battery.
For deep cycle battery bank capacity calculations use:
Total Amp Hour capacity
subtract 5% (most batteries will never fully recharge)
divide by half
subtract system inefficiency loss (resistance, electronics, etc.)
The remaining value is your actual, usable amp hour capacity of the batteries.
For instance:
1,000 amp hours of battery capacity
-5% (no total recharge)
= 950 amp hours
*50% = 475 amp hours
-6% (system inefficiency loss)
= 446.5 amp hours
In this example system, 1,000 amp hours of deep cycle battery capacity yields 446.5 amp hours of regular use capacity.
If that doesn't depress you enough, measure the 12VDC amps of a standard incandescent reading light or a 12VDC RV type florescent fixture. Just a few hours of reading at night can blow through 40-50 amp hours. Laptops can draw >20 amps @12VDC. A few hours writing your novel can easily drain more than 100 amp hours.
A compressor motor, such as that on an aircon system, is a big draw at 12VDC.
Electricity works on a relationship of watts divided by volts = amps. For a given load (amount of work), lower voltage = more amps.
For instance, a 100 watt load at 110 volts draws .91 amps. The same 100 watt load at 12 volts draws 8.3 amps.
If you think making all your heavy load systems 110 VAC and using an inverter to power them is the magic solution, remember that you are still drawing the inverter's energy from 12VDC batteries, plus you typically suffer 5-10% efficiency loss in the inverter.
This is the big flaw in all the OTR truck no-chassis-engine-idle-air-conditioning systems I found - they all use inverters and 120VAC compressors.
Also, keep in mind that air conditioning systems can develop startup head pressure that requires 2 to 3x their rated amp draw to overcome. You need LOTS of extra amp capacity to power an aircon system.
Unfortunately, with electrons, there is no free lunch.
If you use a lot of electrons like we do in our daily life of full time overlanding, you use a lot of battery amp hour capacity.
We have 840 amp hours of 12VDC AGM deep cycle capacity and that is usually barely enough for us. But, again, we use a lot of electrons. YMMV.
Our camper aircon is 120VAC, so we need to run our 120VAC genset to power it.
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