Frequently Asked Questions
Absolutely NOT! It seems too good to be true, but not if you think about it!
In our house in Southern NY, we have an air conditioner in the living room set to 70 degrees which we turn on when outside temperatures hit 80 (because the sun is streaming through our west-facing windows it gets hotter inside!) That's only a 10 degree temperature differential, but the air conditioner compressor is running 80-90% of the time because cold air is constantly spilling into the hall and the other rooms of the house and the heat gain through the windows is a lot. It cycles off sometimes, but a few minutes later it cycles right back on again (because there is no insulation or doors to keep that cold in place.)
Contrast this with our CoolBot Cooler, which is set to 38F degrees and it is regularly 90F out here. That's a 52 degree temperature differential! WOW! But the coolbot controlled air conditioner runs only about 10 minutes of every hour. The reason is that the room is small (11x17 inside), TIGHT and well insulated! There is no leakage, or heat gain from windows! Now... obviously when we load up a couple tons of field-hot watermelons... the air conditioner is running like it does in our house. Same when we have to open the door a lot to load in new produce. But once things cool down again (which is fast), it goes back to the 10 minutes per hour holding run time.
Yes! We have over 1000 mobile applications running CoolBots, on trucks, vans, box trucks, slide-in units in the back of pick-up trucks, boats and trailers. We've learned a lot over 7 years of mobile applications. Here's the GOOD, the BAD and then Critical "technique".
1) We were worried about the window type air conditioners not holding up to running over the road but they are running great, and the first ones went in in 2007. We even have boat application with people crashing through waves on commercial fishing and oyster boats and STILL no problem -- the same units have been running for years!
2) When people insulate well (a lot of them don't in mobile applications). It works great -- this is a big issue for us. People are trying to save every inch in their vehicles, so they often don't insulate well, or they don't insulate the floor of the vehicle and COLD SINKS... so then we have trouble until they insulate them correctly. See techniques, below.
3) We are super cheap and robust compared to other mobile cooling solutions.
4) You can run off the alternator on your vehicle IF you buy a 12,000 BTU air conditioner or smaller and an inverter (which can limit the size of your application or how cold you can get. For spaces up to 8x6 that are VERY well insulated, you should be able to hold 38F.) Otherwise it makes more sense to use a generator. More on this in the "BAD" section -- and inverter information in the "HOW TO" section.
1) A lot of people want to use RV air conditioners which we don't love for the following reasons:
a) They are REALLY expensive per BTU -- especially when you try to find one with a digital display. Dometic makes the original "BRISK" RV air conditioner which is digital... they have a sleeker looking one that is more expensive called the "Penguin" that's actually NOT as good for this application. So get the cheaper one (it's bigger on top which gives us more surface area to play with)
b) They are annoying to set up, because you are working over your head and up in a hole AND you can't see what you are doing... so it's hard to put our FIN sensor into place correctly and worse yet, if it falls our or ices over... you won't know unless you look with a mirror and flashlight.
c) Because of the VERY limited area that they are sucking and blowing out of (14x14) there is a BTU-transfer penalty of almost 30%... so... you buy a 15,000 BTU unit, but it only puts out 10-11,000 BTU's of cold! Which makes them even more ridiculously overpriced.
d) For all these reasons... even in vans, it's not so easy to get below 40F with an RV air conditioner.... In smaller spaces... maybe, yes... but... it's just weirdly harder than with a window unit which is of course SUPER easy to work with.
2) NC State has really detailed instructions on how to build a mobile cooler (the Pak N' Cool) with a CoolBot including mounting a window air conditioner in the side of a trailer... other people do this on vans and trucks as well (using window units). RV units are NOT as common. To learn more, click on the RESOURCES section at www.storeitcold.com and then click on COOLER CONSTRUCTION
3) We are not a great choice for people that need big mobile spaces cooler (like big box trucks) that run while they are driving because it's too expensive to run off your alternator and an inverter with bigger than a 12,000 BTU air conditioner. The people running larger trailers (we have people running 20 foot trailers on coolbots) generally run on GENERATORS and then 24,000 BTU air conditioner.
CRITICAL HOW-TO INFORMATION
1) For mobile applications we only recommend POLYISOCYANURATE rigid foam insulation OR sprayfoam (or a combination)
This is available in Lowes and Home Depot -- so it's super easy to get! It's kind of yellowish slightly... NOT the bright white stuff. That's EPS. That's bad. Polyisocynaurate has the highest r value per inch. Shoot for at least r20 if you are going down to 38F it has foil on one side. The foil has to always face the "hot" side.
2) Don't bother with radiantec(or other brands) bubble foil insulation if you are doing the foil with isocyanurate. It's extraneous
3) DO use Urethane sprayfoam like "great stuff"... NOT the latex version... that way you can cut the pieces and then catch the gaps with the Great Stuff. NC State's article an video demonstrates this really well.
4) Some people hire a spray foam installer to spray insulation in. Sometimes they tell you that they have amazing r-values per inch. They have just under r7 at BEST. so... make sure they do at least 3 inches if you go that route.4) You can use spray ADHESIVE/glue to hold rigid foam insulation in place... We use "3M high strength 90" adhesive which is freaky strong and available at home depot and lowes and probably amazon. 5) Don't forget to insulate the floor! Cold sinks. 6) If you want to run off your alternator and an inverter, you have to use an air conditioner that is 12,000 BTU's or less. That's fine for even smaller trucks. If you go bigger than that, even on larger vehicles, you have to UPSIZE your alternator (expensive) and upsize your inverter into non-commodity inverters that are tons more money. 12,000 BTU's can limit how cold your space is... Many people that have big box trucks or trailers instead switch to generators. 7) We really like the TRIPPLITE heavy duty inverters. They are a bit more expensive than some other brands, but we think they are terrific. You can buy them in many places... here's a link to Amazon:
In general you want an inverter that can surge to *at least* THREE TIMES the running watts that are listed on the air conditioner box (or the sticker on the side of the air conditioner). Other cheaper inverters definitely work for people. This one is just a bit more "heavy duty" which is nice if you'll be running it for a long time.
If you need more you'll have to use a humidifier, and there is no conflict with running a humidifier and a CoolBot. Simple/cheap vapor humifiers can even come with humidistats now on amazon.
If you need lower humidity, you'll have to use a dehumidifier -- which means you'll have to account for the extra heat that the dehumidifier puts out (which just means upsizing the air conditioner a little)
Even in Arizona people end up in that 80-90% humidity level. Outside it might be 25% RH, but when they open the door, and that hot (apparently dry) air cools comes rushing into the room and cools down by 50-60 degrees... that exact same air that OUTSIDE shows up as a RH of 25%, will now measure at 80-90% inside the cooler (colder air can hold much less moisture, so the humidity levels go way up.) Physics is phun.
The CoolBot is NOT just a thermostat! Check out the short "How It Works" section. And yes, the CoolBot does include a digital thermostat so you can set it to run at whatever temperature you want (down to 32 degrees).
We cover this at length in the "Who should NOT buy a CoolBot" portion of the website, but to summarize: A CoolBot system will NEVER freeze up, BUT it can not always be able to get you down to 32 degrees! If your door is being opened and closed a lot, 32 degrees is impossible (for us) to reach!! This is a problem with the physics of the small fan and transfer surface area in air conditioners A conventional walk-in cooler compressor can do it, but a CoolBot can NOT!"
Really, anything below 36F becomes difficult for the CoolBot to reach if fresh hot material is being put in the cooler and it's being opened and closed more than once every 10 minutes. We have hundreds of customers happily using Coolbots at 33-34 degrees, but it works because they open the doors only a few times a day. (Bars and pubs for example with secondary coolers or keg coolers that might be plumbed in). It's super easy for the CoolBot to cool down to 38 degrees and even 36-37 are not hard with normal use (but again, it's a stretch if you are opening and closing the door more often than every 10 minutes.)
Yes, it will definitely work even with the higher humidity. Florists and flower growers seem especially happy with the CoolBot. We are often told that the CoolBot allows for more humidity in the air which keeps the flowers better. We're pretty sure this is just an illusion. The flowers are happier, yes, but it's just because you have so much less air blowing around the room with one fan instead of four, so they aren't getting blown on and dried out that way as much.
For florists (and cheese-makers) that need to keep a lot of humidity in the room, it has been our experience that using a larger than recommended air conditioner is a good idea. The larger air conditioner means the compressor runs less often keeping more humidity in the room. If you undersize your air conditioner from our recommendations (as lots of people do to save money) it runs more often. You will probably reach your desired temperature BUT the air in your room is CONSTANTLY running over the cold fins and moisture is (constantly) condensing out. In a correctly sized system the air conditioner compressor is generally running less than 25% of the time (although the circulator fan might be running, but that doesn't cause dehumidification). Bigger systems might be running only 1/6th of the time with very little dehumidification.
No. It doesn't need to be because the CoolBot has it's own digital thermostat with dual temperature sensors. You just use that instead of the thermostat on your a/c unit. The CoolBot thermostat can be set to from 32-60 degrees (see above note that 32-35 degrees is hard to achieve unless you've oversized the air conditioner and aren't opening the door a lot)
THANKS! Unfortunately... no... you can't mount a/c unit's in a side-ways orientation on the ceiling, you'd have to build a sort of alcove on top... and that doesn't seem worth the trouble. You COULD use a "split a/c unit" but they are much more expensive than standard window a/c units and most require professional installation, so... it would seem like it makes more sense to stick with what you have. Another (seeming) option is one of the "portable a/c" units which use something that looks like a drier hose to vent the hot air out. We've had several people try these and they do NOT work, so don't waste your time. We've had some warehouses (and more than a few restaurants) mount the a/c units so they are blowing into the restaurant. This is great when it's cold out, but the extra heat that you throw into the place during the summer isn't so great! You have to double the size of the a/c cooling the room - so it's not just uncomfortable it's not a good decision from the perspective of "responsible energy use".
THIS IS A LONG ONE, but the summary answer is YES! INDEPENDENTLY VERIFIED!
Our original efficiency claims were based on an earlier study done by University of Georgia on cooler efficiency (that study has nothing to do with CoolBot it was just looking at where the energy use is in Walk-In's and they found that it was not the compressor as much as the fans). If you just think about the number of fans operating in a standard reefer unit (4-6 that are on ALL the time inside and an extra 1-2 outside) vs. the number in operation in a window a/c unit (there's just one and it doesn't have to be running all the time if you are in 'Energy Saver' mode) there's an immediate reduction in electricity use right there that is very significant. Obviously in both cases we are running similar sized compressors (in fact we up-size the compressors for coolbot installations so there is actually somewhat of an energy penalty if you JUST looked at compressor use) but the penalty is very small and the savings from the fans is HUGE, so there is an obvious net gain.
Several customers that had "conventional" walk-in units and replaced them with a CoolBot in the same physical box report a significant drop in their electric consumption. You can find this by googling around - one guy reports that he ditched his old walk-in compressor, TRIPLED the size of his cooler, and is running the same electric bill. The problem is that all these (wonderfully positive!) reports have their cooler electricity mixed in with their other electrical useage so it doesn't really give us an exact percentage number - just that "things are much better."
We've only had a few people report in where they could actually tell us how much they saved. The savings are HUGE (like 60%+ energy) savings but... the units that the CoolBot replaced were really old and probably not made or running very efficiently, so we look GREAT in comparison, but what if you compared us to a modern new compressor -- can it really be that much more efficient?
NYSERDA, (the NY State Energy Research and Development Authority) contracted for an independent analysis to see just how much more efficient the CoolBot is than a standard cooler. We were hopeful that FINALLY we would get an exact answer to this question.
The <35 page NYSERDA study confirms that the CoolBot works great and does not stress out the air conditioner or push it into unacceptable use cycles or pressures (which is another question that we get asked a lot) so that was nice. And... the end result of the summary is that the YES! CoolBot is more efficient than a conventional walk-in cooler. HOWEVER, this study was NOT done with a real walk-in cooler and a real coolbot-air conditioner!! It was done with a modeling program on a whole-house air conditioner that uses a different compressor type and two fan motors (instead of one), so... it's not really as useful as we would have liked (we wanted them to just measure watts spent on two comparable coolers.)
I know we shouldn't be complaining, but... even though we "won", we didn't win by much at all and it was only because of fan cycling. We don't feel like it's a fair study because the comparison was with a whole house air conditioner with a different style of compressor and multiple fan motors - change any of those factors and our own calculations are back to us being 25% more efficient at minimum compared to conventional modern walk-in units. Still, we are really grateful for this study, and we agree they carried it out in an independent and logical way. But... we're still waiting for someone to do a real-world side-by-side comparison!!
Yes! We now have thousands of meat folks including over 100 small commercial meat processing facilities using coolbots. Most of our meat folks are a few hunters who got together and invested in one. Obviously you have to size the a/c unit to the size of your walk-in cooler box as per our chart AND you have a walk-in cooler built to industry standard specifications (4" of styrofoam insulation in walls/floor/ceiling.) If you meet those requirements, the CoolBot will keep whatever your want (produce, flowers, meat, prepared food, dead bodies in mortuaries) at whatever you set it at down to 33 degrees. What the CoolBot can NOT do is: 1) Keep things frozen 2) Keep things cold when you have a substandard cooler or too small of an air conditioner.
I think because our units are so inexpensive, a surprising number of people try to approach the rest of the structure in an inexpensive way, too, so they build coolers with standard fiberglas-house insulation or even just use it to try to cool an uninsulated storage room. It won't work! The fiberglass actually DOES work for awhile, but outside humidity condenses in the walls making the insulation sag and filling it with mold and mildew. So... use the thousands of dollars you save buying a Coolbot to insulate your cooler with styrofom insulation (it's not THAT expensive!). We sell to a lot of hunters and hunting camps as well as people who make hamburgers and other meat-containing prepared foods and they have been very happy with the performance of the CoolBot.
Please see our section on what works and doesn't work. Floors are important for people cooling below 45 degrees because cold sinks and the ground always stays warm. By skipping the floor you've created an endlessly hungry "cold sink" that is sucking money out of your pocket in the form of electricity. The CoolBot will WORK without a floor, but it's going to cost you. Below 40 degrees if you are going to skip the floor you should size up a level on the a/c unit. For hunters only running the CoolBots in the fall... it's not going to pay to put in a floor because you don't run that many months of the year, but everyone else should (below 40.)
For people installing CoolBots on trailers you MUST have a 4" thick insulated floor or the CoolBot will never be able to keep up with the cold you are dumping down the highway.
Standard insulation is 4" thick styrofoam on walls, floor and ceiling.
Just as important as the floor is that you use tape, caulk or sprayfoam to seal up every edge and corner in your cooler. Even a 1/4"x2" hole dumps an ENORMOUS amount of cold (and your electricity $) into the environment.
(From a Virginia Flower Shop)
This is easy to fix, you just need to lower where you placed the CoolBot's frost sensor to where you see the ice first forming (With Samsung A/C units it's always the bottom left hand side of the fins).
[Note from Ron:] While I'm so happy that this is working for them, I feel like they are undersized on the size of their a/c for this application and probably have lower humidity than is ideal for floral coolers. If you are a florist wanting to run in "Medium" fan mode, then PLEASE size up a level on the A/C. Also, the display coolers with windows are VERY lossy, So consider sizing up again if you are running with a wall full of glass doors.
Obviously these folks are happy even given my concerns... I know we're overly cautious in our recommendations, but part of that is because we are used to having to cool a couple thousand lbs of field-hot veggies here on our farm and it takes a lot of BTUs the first few hours to GET them cold. They are getting cold flowers straight from their distributor... and they don't weigh all that much. Also, our cooler is under shade, but it'll be 90+ here in August. Their cooler is in an air conditioned store...
Also please note that MOST all the florists are running in high fan mode without a problem. One woman did make a deflector because she had a small cooler and she wanted the air to go in a different direction (it was nailing the flowers across the way). So consider the placement of your a/c unit when you install it so that it is blowing in a safer direction!
Yes. But you have to install multiple coolbots. Our biggest installation so far is 60x40 with high ceilings. It's a watermelon farm so they are doing a lot more mass than most people (but they don't need to get it as cold). We saved the guy tens of thousands of dollars. Someone also did a 40x40 installation for meat storage for the "Boar's Head" brand saving over $25,000 in installation costs alone (not to mention ongoing electricity savings). 20x20 installations are very common for us and require the purchase of two or three coolbots and 2-3 a/c units (depending on temperature and use and tons of product coming in if it needs to be cooled). We're still much cheaper AND when you can program some of the units to only kick on at peak loading. There is also safety in redundancy - multiple units means that even if one unit goes down you still have others running so you don't lose everything! STATISTICALLY speaking we are tracking very low failure rates, but that's not much comfort if you are one of the people that has a problem.
Yes as long as you have some ventilation into the space. We have a lot of basement cooler people now -- many of the people who do home wine cellars put them in their basements. That's super easy. Restaurants doing secondary coolers (that don't get opened as much) and keg coolers in bars are all common examples of commercial basement coolers.People worry about heat build up in the basement and the water that drips out the back of the air conditioners.
- Heat Buildup. This depends on how often you open the door *and* how cold you want the cooler to be. For wine cellar folks, it's not even noticeable. Wine cellar folks can get away with a cooler in a basement with no ventilation and not even notice most times. Even for restaurant folks it's surprisingly little. You should have two windows "a couple inches more than cracked open" for cross ventilation and you'll be fine even in the summer if it's a secondary cooler at 38F or above. Colder than that or more opening -- then still a couple windows is fine, but in the heat of summer, open them up more.
For folks that have just a single window it's will be warmer, but it's still not horrible. I visited someone's cooler where the backside was venting into a storage room that was 8x14 with just a single opening and while I didn't like the noise of the air conditioner on my head (we were in there for a long time) it never actually got very hot --hotter than outside, but not bad at all (but he said he didn't open the door even one time per hour.)
- Water dripping out the back of the air conditioner. For most people this is irrelevant. Put a bucket underneath just in case, but probably you will never have to empty it. Or maybe once a month if you live in a humid area. The water that drips out the back comes from the more moisture-laden air that comes in every time you open the door. It condenses on the fins, then is channeled to the back, and if ENOUGH water is collected it will drip out the back (otherwise it just evaporates). In a residential air conditioner, you get a LOT of condensate drip-drip-dripping out the backside because people are constantly coming in and out, and doors are rarely closed. But in an air conditioner used in a cooler, it's small and sealed up so you get very little water condensing -- it evaporates before it can drip out. Even a restaurant in Georgia that was worried about it wrote recently to say that he only has to empty it ever couple weeks even in summer. (It's a secondary cooler in his basement, not the primary)
- Gas fumes out the back of air conditioners. There are NO fumes whatsoever on the back of the air conditioner. It's a completely sealed system, so all that is produced is heat. You will feel some air, but it's just from the fan that is blowing air over the warm fins.
Although we have people that have the backside of the air conditioner into a sealed space with NO windows, I don't think that's a good idea. I'm writing so positively about how little water and heat is produced, and that's true, but "very little" is not the same as "nothing". You should be able to open up at least one window, or have a door that's getting periodically opened to vent the heat out unless you are wine-cellar user.
Also, think about the noise the back side of the air conditioner makes. I wouldn't want it in my living space.
Also, I noticed that there are air conditioners advertised that cool AND heat. Is that a better choice for me?
Okay, to answer your winter, cold question: What we do on our farm (we also require heating in the winter) is buy a little $12 space heater (not a radiant heater, only use one of one of the ones that *blows* hot air - that's important!) They are like $10-12 from Target or Walmart.
We plug it into a pass-through thermostat (you can buy them at FarmTek.com)... This is the one I like: DuroStat™ Portable Waterproof Prewired Thermostat Item# CR2045... it's about $52.00. Make sure you choose one that can be set for BELOW 40 degrees F!
There are cheaper ones (for $34) but then you have to wire them yourself (which is actually really easy... we just cut an extension cord in half and screwed it in and then caulked the holes)... which I'm not recommending because I'm not an electrician.
We set the COOLBOT 2-3 degrees warmer than the heater (so they don't overlap and fight with each other).
The little space heater barely has to run to keep the room warm.
It does NOT dry out the air (I think because it runs for so little time...just a few minutes per hour in total).
We don't recommend the "heating and cooling" air conditioners because they are so much more expensive than normal air conditioners. ALSO (the ones I've seen so far) aren't even automatic!!! So you have to set it to cool mode or heat mode... which is bad if you live in a place that has cold NIGHTS and warmer DAYS.