Roof mounted A/c on a hard top?

[OPCOM]

"Floor Mount A/C only evaporator with four round vents surrounded by Steel case for durability. Designed to sit between the seats, or the floor in the rear of a vehicle. The evaporator has four round louvers that can be pointed in all directions or closed off completely. The controls are located on the center of the unit. The evaporator has a three speed blower motor with a dual fan setup. The evaporator has approximately 310 CFM and 18000 BTU. The evaporator unit is compatible with R-134a and R-12 refrigerants.

The evaporator unit includes:

* Three speed blower motor
* Adjustable temperature thermostat
* Evaporator unit mounting hardware
* Expansion valve
* Drain tube
* Orings
* Two rubber grommets
* Available in 12 or 24 Volt

The evaporator unit measures: 13" wide x 9" deep x 19" tall

If you would like to add this unit to a complete kit please go to the complete kits page and select the make of your vehicle. In that selection we offer complete kits with "select an evaporator" option. Add this evaporator to your shopping cart, and select the kit for your make, add it to the cart and follow the directions for checkout.

This evaporator unit is manufactured in the U.S.A."


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18000 BTU is at the low end of the super-cold requirement for 100+ degree days, but it will be much better than a small unit and the air can be blown at the driver and passenger. That unit would fit between two driver seats.

To duct or not to duct, that is the question. There is also space under the existing companion seat. Quite a bit of space. Ducting would be necessary there. I'd thought about ducting up from there behind the seat, but when the seat is raised or lowered, the space there is diminished during that operation and round ducts might not work. Ducting can be done wit other units too.

Most people prefer the A/C to blow on them in a vehicle. This helps relieve the heat of the sunlight impinging directly on the occupants. The deuce cab is big enough, the main question is how one would run a pair of at least 3", preferably 4" ducts to the front, and then make a u-turn to the ocupants. Low resistance to airflow goes a long way to making the most of a blower. The dicts could be any shape, as long as the sross secional area was respected. The truck was never designed for A/C so even more creativity is necessary. Maybe overhead?

The best choices might be the evaporator between the seats or an underdash unit. I am not convinced of the BTUs of the underdash units. I've called that Nostalgic Air place and the guy beat around the bush, maybe he didn't know. But compare the size of that 18000 BTU machine to the typical underdash machine.

I hope D-man would chime in here and give us the part numbers for the compressor, condenser, and underdash evaporator/blower.

 

[OPCOM]

One option that has not been discussed is the interior roof mounted evaporator. Here are two:

UD-560 Overhead Roof Mount Evaporator Unit
approximately 540 CFM and 32,200 BTU.
The evaporator unit is compatible with R-134a and R-12 refrigerants.
The evaporator unit includes:
* Three speed blower motor
* Adjustable temperature thermostat
* Evaporator unit mounting hardware
* Expansion valve
* Drain tube & cork tape for hose fittings
* Orings
The evaporator unit measures: 31-3/4" wide x 14" deep x 6" tall
http://www.nostalgicairparts.com/air-conditioning/ud-560-overhead-roof-mount-evaporator-unit-484.php

UD-550 Overhead Roof Mount Evaporator Unit
approximately 510 CFM and 22,700 BTU.
The evaporator unit is compatible with R-134a and R-12 refrigerants.
The evaporator unit includes:
* Three speed blower motor
* Adjustable temperature thermostat
* Evaporator unit mounting hardware
* Expansion valve
* Drain tube & cork tape for hose fittings
* Orings
The evaporator unit measures: 26.5" wide x 12" deep x 5.5" tall
http://www.nostalgicairparts.com/air-conditioning/ud-550-overhead-roof-mount-evaporator-unit-483.php

Normally these are mounted at the rear, but why blow ait at the windshield?
How much vertical room is there in the cab ceiling above the top of the windshield glass? I can imagine this beast at the front blowing right at me. Would 6" of equipment at the front, right behind the windshield wiper motors, obstruct the view too much?

 

[Recovry4x4]

Cool suit?

 

[OPCOM]

Red Dot has some ceiling mount and back wall units as well. Different aspect ratio on them, one or another might be better or worse..
http://www.rdac.com/Pages/product_pages/units_index.html#

attached are some interior measurements of the M35A2 cab I just took. They are not perfect but are as good as I could do with a tape measure.

 

[OPCOM]

Cool suit?

haha talk to me when I get some armor! I guess I could just dump some ice down my britches.

 

[garp]

RedDot model r-9727. 24 volt, available with heat option. has the evap and condensor in one unit. they work really good in the construction/mining business. tough as nails too. Or find the unit from a Cat 988B/F or 992C/D. I have one and thinking it will fit under passenger seat, heat and a/c in one. But no condensor in that one.

 

[DoctorCheney223]

Will one of these mounted on the top of the cab of my M109 keep us cool in the 100+ degree Las Vegas heat?

I want to make it fun for the kids and not have them red-faced and minutes away from heat stroke while cruising around in the truck. This model has a 15,000 BTU capacity.

RV PARTS OUTLET



thanks,
Ron

 

[OPCOM]

It should keep it much cooler than 100+ degrees. If you are sealed up decently.
Note the pevious comment about positive air pressure at the very back of the cab in front of the box and how it might oppose the condenser air flow on that kind of unit. Those are intended to have few or no obstructions behind them.

 

[FireFighterHill]

Will one of these mounted on the top of the cab of my M109 keep us cool in the 100+ degree Las Vegas heat?

I want to make it fun for the kids and not have them red-faced and minutes away from heat stroke while cruising around in the truck. This model has a 15,000 BTU capacity.

RV PARTS OUTLET



thanks,
Ron

Bad thing is you would need a generator to run it. So not only the cost of it but the cost of buying and running a generator to power it. I think the best option is either a red dot rooftop unit. Or if your really handy like Mike you could do the same thing he did on the diablo build. Which is to modify the evap from another vehicle to work in the deuce and duct the vents.

 

[broman78]

we are over thinking this just do what this guy did. I won't be pretty but it will work. I was in Houston on Wednesday and I saw 108 in my rental. I feel sorry for the people without ac.

 

[jesusgatos]

Jesus,

Could you please share details of your installation. Pictures would be much appreciated.

Thanks,
Rick

Here are a couple of pictures that show how/where I mounted the RedDot R-5045 AC/heater that I am using in my M109 motorhome conversion project. I'm using this condenser, and I haven't even thought about what to do for a compressor yet. I've been talking to the people at RedDot and Sy-Klone about fresh air and recirculating air filtration and cabin pressurization systems though. I actually just sent some CAD files to their engineers today so they can help me decide how to duct everything in order to maximize performance. I never gave much thought to airflow and this kind of stuff before. I'll post more as I learn more and finish-up this project (at least the AC/heat part of it).

 

[m-35tom]

i put a/c on my unimog u1300. cab is much bigger, some insulation and is sealed very well. kysor roof cond/evap unit used $20, volvo compressor used $25 made 2 pulleys some a/c hoses and-----------cold enough but not for 100f days.
forget about kysor unless you get a super deal on complete system, parts are expensine, hard to get, and their service sucks. nothing ever in stock takes months to get stuff.

 

[73m819]

in cal, the D9 and 10 dozers that we had, had after market roof a/c, a compresser on the engine, a drain line, this mounted to the roof hatch , with all window cab, it was like a convection oven , the a/c would cool the cab cool enough to ware a long sleave shirt in 100deg

 

[papercu]

Red Dot already makes the units for HMMWV. One sold on ebay last week for 1800.00 . Wayne

 

[bgekky3]

Here is one way to do it.

 

[OPCOM]

Here are a couple of pictures that show how/where I mounted the RedDot R-5045 AC/heater that I am using in my M109 motorhome conversion project. I'm using this condenser, and I haven't even thought about what to do for a compressor yet. I've been talking to the people at RedDot and Sy-Klone about fresh air and recirculating air filtration and cabin pressurization systems though. I actually just sent some CAD files to their engineers today so they can help me decide how to duct everything in order to maximize performance. I never gave much thought to airflow and this kind of stuff before. I'll post more as I learn more and finish-up this project (at least the AC/heat part of it).

IIRC that unit has the plenum vane to direct air to either or both compartments. One in front of the unit as shown in the pic, and one behind the unit, would be into the cab in that pic. Nice!

 

[jesusgatos]

Yes, that's exactly right. The AC unit is going to be ducted forward into the cab. We're also doing some really cool stuff with fresh-air and recirculating air filters/pressurizers.

 

[Oldvw2]

Thinking out loud here - how about a semi truck APU?:
Kohler Power: 3APU-24V-HC: 3APU-24V-HC: 3APU-24V-HC: Idle Reduction: Mobile Generators
A lot of states are passing anti-idling laws so drivers are adding these so they can stay in the sleeper without running the engine. I have seen some at the docks at work and they are pretty small and quiet. They look to be expensive new (~6k) but maybe some are starting to show up in salvage yards....

 

[rchalmers3]

Warning: Thread ressurection in progress>>>>>

I thought I'd bring this old thread up in order to add a few thoughts and introduce a possible resource that may be of service to those of us who seek a solution to the heat we suffer in our hard top deuces. A major caveat: these thoughts of mine are pure opinion and are based on zero experience... I have not actually gone out and bought one of these units and put my money where my mouth is. Having said that, I encourage anyone who takes my ideas a bit further to post up your results and findings. Eventually a best method will arise from the mass confusion...

In all the threads I have encountered during my short time here on the forum, I have not seen or read of the resource I will mention. but before going further, let me explain my reasoning.

When it comes to adding complexity to what is a very basic truck, I aim to do so while installing minimal problems or adding a lot of maintenance. To my way of thinking, I would rather not utilize a split system that requires:
* the installation of a engine mounted compressor with complications to the drive belt system and bracket fabrication
* the plumbing of air ducts or hard lines to a floor or roof mounted evaporator
* the installation of a condenser forward of the radiator

I prefer to mount a unit on the hard top that is self contained, durable and requires only a dedicated 24v circuit to the roof unit with minimal space intrusion (2" or less) into the cabin.

The electrical demand of a self contained roof top system may require a modification to the alternator and regulator to accommodate the additional (6-12a) amperage load, but I believe that if needed the factory alternator can be worked on and made to produce the required output while retaining it's physical characteristics and mounting geometry. Thus the under-hood changes would be minimal. Most of the installation work would be to fabricate a front to rear roof support (shaped like an "H") that would carry the approximately 50-90lbs of weight of the roof unit. A 1.5" medium wall square tube chassis would be more than sufficient and could be designed and fabricated to fit inside the cabin to follow the contour of the roof skin and attach to the hard top rim for support.

Regarding the size of the unit and capacity to cool, I do not have enough experience to advise on the BTU requirements. That has been discussed but not determined as a certainty. Whether 10k, 20k or 30k BTU unit will cool a truck is a guess. As others have said, more is better..... I do believe that a roof mounted system is most likely to provide a pleasant atmosphere because the cold air can fall to the floor without a lot of blower noise. I have installed a few aftermarket under dash units and have been dismayed at the lack of performance of the circulation, both of the air coolness and volume and of the ability to direct the ducted air by aiming the vents. I believe a roof mounted unit is an elegant solution and will avoid the issues of blower noise and/or underwhelming performance.

Some years back I found a company that sold roof mounted units for use on NATO vehicles. Webasto was selling 24v "military" units to Mercedes Benz for mounting on Unimogs, and since I was playing with Unimogs, I thought it would be prudent to investigate the products they offered. See: Webasto ? Air-Conditioning Systems for Defense Vehicles

Well, the price stopped me. The smaller unit they then offered: "Compact Cooler 5" (see photo of the data sheet below) was listing at $5k out of Miami, plus freight to Costa Rica and import taxes..... The cooling capacity is specified at 5kw or 17k BTU, enough I thought for the confines of the Unimog 416. For additional cooling they also offered an 8kw (27k BTU) unit. But again, the entry fee.....

Fast forward to last night. Webasto has updated their website and no longer offers their military products online. You now have to contact them to see what they offer. In addition, their new "emergency vehicle" products are now offered as split systems: utilizing an engine driven compressor. But for those of you seeking, I have another resource: In California there is a company named "Expedition Imports" who claims to be a distributor for Webasto products. The owner of Expedition Imports is Scott Ingham and he once gave me a very favorable quote on a unit. You can find his company here: Expedition Imports Corporation Home

I hope this posting is of service to someone like myself who seeks relief from the heat, but unlike myself has sufficient financial resource to go forward with a unit and installation. Good day to all.

Rick

 

[ke5eua]

Without starting a new thread I am toying around with the idea of doing this to my 818. Has anyone actually done this? I am aware I will need to brace the roof, and I already have an inverter to handle the power needed.

I'm looking for prof of concept pictures that this has been done. I went to all the links and nothing definite.

I have explored the option of truck mounted a/c but since all my ham equipment is going inside the truck the option of running a small genset on the back deck or even just running of the inverter and playing on my radios during an event without running the big engine is a plus.

Forgot to add, roof weight will be between 72 - 108 lbs depending on which a/c I get. It's a toss up right now, most likely be the 72 lb one though.

Duo-Therm Brisk Air II 13.5K BTU

http://www2.dometic.com/enus/Americas/USA/RV-Products/climate/ac-display-page/?productdataid=107566

Then again, could go with the heat pump model with is 105 lbs.

http://www2.dometic.com/enus/Americas/USA/RV-Products/climate/ac-display-page/?productdataid=66936