| Author | Message | ||
| FAST FRED (63.233.189.68) Rating: N/A |
Yes folks the Red Dot Corp has introduced their R-6900 which produces "up to 10,000btu" of cooling using 12V or 24V. Haven't seen the unit , only the addvert for it. May just be a cheapo inverter and OTS unit , but it Could!! be a real DC unit! Might solve a problem for someone with a ton of batterys. FAST FRED | ||
| FAST FRED (65.154.177.20) Rating: N/A |
From Google R-6100 Air Conditioner Unit For heavy-, medium- and light-duty trucks, construction and agricultural cabs. The R-6100 is the ultimate rooftop air conditioner design. Red Dot went the extra mile in designing a lightweight, high-capacity unit with a styled low profile that fits the aerodynamic truck designs of today. A sloping front rides comfortably over center marker lights. This is a must when roof space is minimal or air shields are used. A low-profile plenum protrudes barely 1.5 inches into the cab and blends easily into the headliner, leaving ample headroom. Frigid, high-velocity air can be directed 360 degrees through the large diffusers located directly below the double blowers. Also featured is a cab air filter incorporated into the plenum. The heavy-duty design contains tube and fin coil construction, high-capacity receiver drier and Red Dot Trinary System protection switch. The Trinary switch extends condenser motor life and guards against component failure. Should the R-6100 ever need service, only two outside bolts need be removed to access any component. The R-6100 is perfect for most truck applications, especially COE's where space in the cab is limited. Options * Bug Screen (RD-4-4529-0P) * Winter Cover (RD-5-4718-0P) * Universal Roof Mount Kit (RD-2-1302-0P) Specifications BTU's: Cooling -- 16,000 BTU/hr with 36º F (4.7kw) refrigerant temp. and 80º F (26.7º C) wet bulb entering air Air Flow: 265 CFM (450 m3/h) Weight: 44 lbs. (20 kg) Condenser Coil: The coil is aluminum fin and copper tube construction. This material selection, which includes a tube of .022" (6 cm) wall thickness, results in an effective, lightweight, and rugged coil. Condenser Motor/Fan: The motor is a permanent magnet type selected for its extended life. The motor is sealed and a slinger ring and hub cap added for weather protection. The fan is aluminum with heavy duty spider and riveted blades. Current Draw: 33 amps @ 13.6 VDC (includes 4 amps for A/C clutch); 16.5 amps @ 27.2 VDC (includes 2 amps for A/C clutch) Models: R-6100-0 (12 VDC), R-6100-0-24 (24 VDC) Usual disclaimer , NO I dont own the Red Dot Co. FAST FRED | ||
| James Maxwell (Jmaxwell) (66.81.51.240)
Rating: N/A |
The specs are somewhat vague. Although no mention, I presume R-134. No mention of the compressor used other than the clutch power draw. Also no mention of the refrigerant lines to connect the compressor to this roof condenser/evaporator. The main defiency I see in the specs listed is the CFM delivery. 400cfm is considered standard ton and at 265 for 1 1/3ton unit, it is grossly under-rated. In the larger open space area of a bus interior, as opposed to the cab on a typical tractor, air distribution is going to be a problem. This is a common short-coming of roof airs; they are under capacity for the tonnage of a/c that the compressor and coils are capable of. This is not a new concept. Bluebird used them extensively in the early days of the Wanderlodge. They did not go over real great for two reasons. Low cfm capacity relative to the space involved and dealing with refrigerant lines from the engine compartment to the roof, which is a hugh problem when u consider the potential for leaks and the routing necessary to maintain proper refrigerant flow, which better be considered if u don't want to wipe out a compressor from lack of proper oil return and "slugging" on start-up. All of these inherant problems can be addressed, but the cost and complexity quickly approaches the point of being un-feasable. | ||
| gary Stadler (68.7.217.217) Rating: N/A |
Um... wait a minute... if an A/C has a "clutch", it's gotta be engine-driven, Nicht-War? I've never seen a hermetic electrical A/C compressor with a clutch.... 12x29 amps is 348 watts... about enough for a decent set of blowers, but nowhere near enough to power a DC compressor of any size... | ||
| Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A |
Looks like FF was dreaming again. Shure would be nice though. BTW, I would like to find one of the older A/C units like I used to see on some vans, I believe. The evaporator and condensor coils were mounted in a roof mounted enclosure about two feet square and about 10-12 inches high with an engine mounted compressor. I want to air condition my one ton Ford pickup and that would seem the ideal way to go. Anybody know where I could find something like that? Don't think I would like the price of the Red Dot unit even if some think I have mega bucks. LOL Richard | ||
| DonTX/KS (66.82.9.20)
Rating: N/A |
I still see them in truck junk yards Richard, some of the cube van types used them quite a while after the big trucks went to inside units. | ||
| Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A |
Yea Don, but here in West Virginia there is nothing that new in the junk yards. LOL Richard | ||
| DonTX/KS (66.82.9.11)
Rating: N/A |
I forgot. Do they even HAVE junkyards? Someone said to me that Subaru was concerned as to why their "Outback" model was not selling in West Virginia. They sent a representative there and found everybody in West Virginia ALREADY HAD a Subaru out back. So I am told. | ||
| Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A |
Right on, Don. The newest model in the local junkyard is early 80's. LOL Richard | ||
| FAST FRED (63.233.189.228) Rating: N/A |
Im guessing that the DC motor can not create the torque to start a system with much head pressure , hence the clutch to allow the compressor to start up then engage. These are simple stick them in the hole on top units (like RV stuff) and do not require the engine to operate for power. They would require a pretty big bat set to be very usefull. With DC only at a 33A draw would make it interesting to see how many 100A "converters " or 100A inverter chargers could keep the bat set charged. FAST FRED | ||
| Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A |
Fred, since the battery draw is only 29 amps plus 4 for the clutch, do you think this ia a completely self contained unit? It don't seem like 29 amps would run a very big compressor. I could not find anything in the literature that would indicate either, but it sounds like it is self contained. Richard | ||
| BrianMCI96A3 (65.40.154.171) Rating: N/A |
Fred, likes to ignore logic when it suits him, since there is no mention of a compressor motor or it's amperage draw in his spec sheet. I know, it's driven by air pressure! I'm guessing that since the cab of a truck is roughly the size of a closet, you could design a closet on the rear of your coach, bolt the R-6100 compressor to your engine and have the coldest closet in conversion history. Brian | ||
| gary Stadler (68.7.217.217) Rating: N/A |
END OF THREAD: For some reason, I seem to end a lot of threads  Maybe I'm just an old Kermuggeony ars.... Here is an email I just got from Red Dot. Nothing like asking the horses' mouth instead of arguing in the blind... What happened here in this thread is that "someone" (Fred?? oops) mistyped the model number on post # 2 and everything went downhill from there. Fred, I've now vindicated you!!!! All in all, GOOD JOB finding the R-6900 !! From the Horses' mouth: The R-6100 rooftop utilizes a engine driven compressor. The R-6100 has a capacity of 16,000 btu/hr and a maximum current draw of 33 amps at 12VDC. (NOW for the GOODIE) The new R-6900 is a complete, self contained system. The R-6900 has a capacity of 9,000 btu/hr and a current draw 18.6 amps at 12VDC including the self contained compressor. The R-6900 also has an adjustable battery level monitor for stationary, engine off operation, plus it cycles on and off for further power savings. I hope this helps. Gary P. Hansen Vice President of Engineering Red Dot Corporation | ||
| DonTX/KS (66.82.9.37)
Rating: N/A |
That is the way to do it Gary, thanks. | ||
| Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A |
9,000 btu plus the fans on 218 watts? I don't really think so. Thats about 1/4 hp. Maybe enough to run the blower on the evaporator and the fans on the condensor. Richard | ||
| gary Stadler (68.7.217.217) Rating: N/A |
Well Richard, if you can't believe the VP of the company, who you gonna believe? !! Maybe if you doubt them that much you oughta email them and ask lots of pointed questions, and report back to us. Here's their contact page: http://www.rdac.com/email.html I think that it's totally possible in this day an age that someone finally came up with an efficient technology. It's just a matter of time. No one could believe a cell phone would be possible 15 years ago... I can't imagine they'd lie to our faces... ....guess it ain't "end of thread" afterall!!! G | ||
| Pete RTS/Daytona (209.165.14.116)
Rating: N/A |
F/F is a wealth of 'misinformation' as usual...how about a little further research next time..or at least get the model no. right!! The self contained model is R-6900 and although their literature claims: 9000 BTU with 39 amps (not 18.6 as per stated above) at 12 VDC, a call to their engineer revealed that the cooling output (under ideal conditions) would be more like 7800 btu/hr. A good EER rating of 10 in a home A/C unit would mean about 10btu/hr output / kw input - 13 EER would equate to 13 btu/hr / Kw input. This unit's rating would calculate out to an EER of a unbelievable wooping 19btu/hr / kw input - if you use 9000btu / 39amps x 12v or a super efficient 16btu/hr / kw input if you use 7800btu / 39amps x 12 v Hmmmm... sounds too good to be true ????? .____________ /_][][]/___/[]__| 1989 RTS-II T70206 6V92-TA DDEC-II V731 4.10/24.5 *--O----------O--* Daytona FL.-Hard Beaches/Soft Women | ||
| Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A |
Gary, well it appears that we CAN NOT believe the VP of Engineering! His memo clearly states 18.6 amps at 12 volts. According to Pete the literature states 39 amps. Quite a whopping difference. Hard to believe a VP of Engineering would make such an error. He would only make it once if he were working for me! Common sense tells me that regardless of engineering technology increases and efficiency gains, you can not get 9,000 btu of cooling with only 18.6 amps. That is approximately 3/4 ton of air conditioning and would require approximately 3/4 hp to produce, not including the fans. I even question the claim of 7800 btu as the Engineer advised Pete. Sounds something like the old saw "last week I couldn't even spell Enjunier and now I are one". Richard | ||
| FAST FRED (63.234.20.237) Rating: N/A |
No doubt the VP gave the amps for their 24V model. The R 6100 was the spec sheet as copied from the Mfg. So, YES there is a 12V or 24V ALL DC air cond being made , exactaly as I reported. No doubt DML will be able to convince the VP that his company is not selling them as it "can't" work. For folks that can solve a problem with DC air cond , whose gona be first? Let us know how it works for your way , and ignore the usual naysayers& nabobs of negativism. FAST FRED | ||
| BrianMCI96A3 (65.40.154.171) Rating: N/A |
Gary... "No one could believe a cell phone would be possible 15 years ago..." REALLY? Well, maybe if they had been buried under a rock for a while. Dr. Martin Cooper of Motorola, (co-inventor of the cell phone) made the first cellular phone call, on a portable device, in April of 1973 The basic concept of the cellular phone was created in 1947 with the Bell Labs invention of radio phones for police cars. FCC restrictions on bandwidth(which changed in 1968)are the main reason cell phones didn't become commonplace until the eighties. By 1987, SEVENTEEN years ago, over a million people were subscribing to cellular phone service. By 15 years ago if you didn't own one yourself at the very least you saw one being used, and knew what it was...unless you'd been under a rock for a while... Brian | ||
| Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A |
Fred, I think you are exaggerating as usual. I never stated it could not work. I only indicated that the data the VP provided is erroneous. Of course it will work. You just need to be able to provide the necessary amount of power. And 18 amps at 12 volts, as he indicated, is definitely not enough power to provide 9,000 BTU of cooling. Richard | ||
| gary Stadler (68.7.217.217) Rating: N/A |
I do live under a rock.... in my Crown skoolie.... maybe Fred lives under the rock next to mine. If so I'd be happy to have him as a neighbor...we'd certainly get things done...and have a lotta laughs together... | ||
| BrianMCI96A3 (65.40.154.171) Rating: N/A |
Fred, now you are just nattering like Spiro Agnew! While I believe that a 12/24v a/c unit is entirely possible, the inaccuracy the specs given, and the dispute as to the ACTUAL numbers certainly weakens the argument. I agree with Richard... The VP of engineering's memo states that Red Dot's R-6900 self contained a/c unit draws 18.6 amps @12V while giving 9K BTU of cooling...YET, according to his memo and their own specs, the R-6100 which utilizes an ENGINE DRIVEN COMPRESSOR uses 33 amps @12V while giving 16K BTU of cooling. So, he's trying to tell us that a unit that does not drive it's compressor (the largest draw in the system) draws almost twice the amperage of a unit that does drive it's own compressor, while putting out well over half the BTU's I know, it's driven by air pressure! Brian | ||
| Gary Hansen (205.153.154.129)
Rating: N/A |
Gentlemen: Sorry for the miss-information on the current draw and capacity on the R-6900. I took it straight from our new product catalog. I didn't bother to check the drawings. Here are the actual performance numbers from our lab at 13.6 vdc at the connector: Ambient DewP AMPS EvapBtu/hr AirOutTemp SCFM COP 80F 59F 42 6640 55F 202 3.4 90F 65F 46 6558 64F 203 3.1 100F 72F 50 7069 71F 200 3.0 The current draw increases with the system pressures, ie. more work being done by the compressor. I hope this helps. Gary Hansen Red Dot Corporation garyhansen@reddotcorp.com | ||
| Gary Hansen (205.153.154.129) Rating: N/A |
I should mention that ambient is defined as the temperature of the air going into the evaporator. Since this is a recirculating air system, the current draw will be higher initially then drop. The 39 amp figure is a typical operating current figure after pull down and the cabin air temperature is in the 70s. Gary Hansen Red Dot Corp | ||
| Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A |
Gary, Thanks for the input. This sounds more reasonable to me. Can you provide the actual BTU provided based on the this information? Richard | ||
| Gary Hansen (12.229.197.218) Rating: N/A |
Richard: The evap btu/hr numbers listed in my earlier post are the actual btu capacities for the listed conditions. They are air side numbers. The true amount of heat being removed from the air. The table formatting got a little screwed up but the conditions are at 80, 90 and 100 degrees F. air entering the unit. The air out is the temperature of the air leaving the air conditioner. I am headed for the Mobile Air Conditioning Society convention in Orlando, so I will not be available to respond to any other posts till next week. Gary Hansen | ||
| JJJ (172.159.220.33)
Rating: N/A |
Thanks, Fred, Looks interesting, especially for a smaller enclosed area. A standard car alternator could keep up with the unit. JJJ | ||
| gary Stadler (68.7.217.217) Rating: N/A |
Phew!!! Can FF and I come out from under our rocks now? | ||
| Doug Dickinson (Dougd470) (65.161.188.11)
Rating: N/A |
Correction Police 2-way radio came out in the 30s as did mobile telephone service by the Bell system. One-way police radio dates back to the 20s. FWIW \ Doug St Louis MC9 | ||
| gary Stadler (68.7.217.217) Rating: N/A |
And get this: Do you know who holds the original patent on spread spectrum frequency hopping (the thing that makes cellphones even possible)... it's the actress Hedy Lamarr! She and a friend conceived the basic premise for spread spectrum communications, and patented it WAY before digital electronics or transistors even existed in commercial form! Of course they were so far ahead of the time that they didn't make a dime, but it's cool that the concept came from a pretty girl who didn't know a thing about electronics!!! http://www.ncafe.com/chris/pat2/ | ||
| BrianMCI96A3 (198.81.26.45)
Rating: N/A |
The conception of cellular phones began in 1947, when researchers looked at crude mobile (car) phones and realized that by using small cells (range of service area) with frequency reuse they could increase the traffic capacity of mobile phones substantially. However at that time, the technology to do so was nonexistent. You are right about Police car phones, I'd read another article the other day that credited Bell Labs with inventing the car phone in '47. Brian | ||
| Doug Dickinson (Dougd470) (65.161.188.11)
Rating: N/A |
I participated in a demonstration of cellular technology in the early 70s with a modified IMTS car phone. It was crude, but workable. I have a picture of an old car phone from the late 30s - consisted of 3 large boxes (tx, rx, power) in teh back seat area. Musta weighed a lot. I had an old single channel tube-type phone in 73 (MTS) and when you keyed the transmiter, the headlights would dim. So - this brings me back to the root subject - how can you get a ton of AC, or anything like it out of 8, 12, 16, or even 40 amps at 12VDC? I would be curious - that would be a breakthrough I would love to look into the technology. |