I know there are a few in the mining industry here. I'm only an operator but just researching. They just replaced the ac units with a new mine air system that just doesn't keep up in 80 degree weather. The unit says 10,000 btu/hr and 800 cfm. I'm curious what systems other mines use and how well they cool. I cook in the cab when loading facing the sun. Just today we finally got some big wigs to come sit in it and feel how inadequate they are. They were shocked so hopefully they do something about it. Our shovels will freeze you out in the summer but we have always fought them on the loaders to upgrade.
The problem is usually space constraints. In a shovel you have a large cab roof on which to mount a/c units so they can be quite large, also it's possible to mount external sunshades/canopies/louvres on shovels to keep the sun from shining into the cab so much. Generally on a loader the roof is the ROPS structure and can't be modified to install a/c evaporators plus the sunshade idea is a no go. Does the cab have tinted glass..? There was a thread on here a week or so ago about the latest tint films which go a long way to improving the cooling effectiveness of a/c units. TBH all we ever used was factory OEM a/c units, but they do take a major amount of maintenance to keep them at optimum efficiency. If the a/c evaporator is mounted in the machine radiator package (that's where they are on Cat & Komatsu) you will have the Devil's own job keeping it clean and efficient. This may give you some ideas -
We have brought the window tint up to them but it didn't gain any traction. Maybe it will this time. One thing I just thought of is they used to have two units. One was behind the seat and they took them out because they were hard to keep up. But those were the primary ones for a while since they let the other system stay inoperable.
They tested it today 45 at the evaporator and 58 out the vents. Pressures good everything like it should be. So something is undersized.
Are you getting too much heat gain from the machine? How hot is the floor? Hopefully there aren't any hydraulics run through the cab. I have zero experience with heavy equipment AC, just things that I'd look at. Those numbers are in the ballpark depending on how humid it is, how much condensate is draining out?
Low humidity and the most heat is coming from the windows. The front window is like 5 layers and feels like a magnifying glass. 58 out the vents isn't good enough when it's 100+ outside.
Maybe the specific film mentioned in that thread might be of use to you in your specific circumstances. I suggest you read the thread to which I posted the link and understand exactly what that film does. It might be your answer. I agree with you that 58 out of the vents is not going to work in 100+ ambient temperatures. It sounds to me like the company has replaced the OEM a/c with something that is either wrongly sized for the application or just plain inefficient.
That's been the conclusion of the mechanics too. I was told they opted not to buy the upgraded evaporator from the company also. Apparently joy global is going to send a refrigeration expert out to see how we can upgrade and fix the machines. I'm gonna retread the tint thread again and pass the info on.
Personally I would suggest to PM the OP from the film thread and ask him for some technical information or spec sheets. I realize he's quite a few states away from you (Al vs Ca) but that's nothing if you can get good info regarding something that will provide a solution for your problem.
Yeah I just PMed him this morning. Thanks nige
58 out of the vent, OK whats the entering temp of the evaporator?? are you getting a 15-20 temp drop across the coil?
Im not sure. The only other thing we checked was the temp of the evaporator was 46. i can't remember if the air is recycled from the cab or pressurized from the air filters.
Well they bought upgraded system for the cab evaporator and blowers. They weren't cheap but they needed them they are lucky it hasn't got real hot as both machines would be down. I'll share more after they install the systems.