Captain Goddammit wrote:... But this thread is about chilling a bus.
And my post detailed the types of A/C unit operation, so people can be aware of the choices they can make, instead of not being aware that they're making a choice, while providing some points on improving efficiency of operation.
> those single-hose freestanding units actually work quite well even though they shouldn't
"even though they shouldn't" is an example of "not technically correct".
There are many spaces that any of the above A/C unit types can cool well, if they're sized appropriately. Different types, or in different modes, have different efficiencies, both electrical and thermal. In a given cooling situation, it is possible that units of the same BTU rating and electrical efficiency, but of different types or modes, will result in one being able to do the job and the other can't. This is materially different from the incorrect "even though they shouldn't". Of course the turn-key solution is simply throw size and power at it: a large A/C unit and the power to run it.
I don't know if you were tired when you read and posted or if you've got your solution for the playa so you didn't give it full attention. If you want to understand, go back and read above. You've already got your turn-key solution that works for you on the playa, so you personally don't need to understand.
Not explained above, but only touched upon, is the difference in how an A/C unit fits in cooling a space vs. how a swamp-cooler cools a space. (This is completely different from how each produces their chilled air
.) That has been covered in the swamp-cooler thread many times, although the thread's emphasis is 1. how to build one that works well on the playa, and 2. how they produce chilled air. It's a very interesting difference (well, to me it is...), as understanding opens up methods of installation and use that provide more effective cooling inside a structure
If understanding how they chill a space interests you, go read. Hint (on a platter): if the hot air is expelled from the interior then you don't need super chilled air to mix with it to lower its temperature
. And further to how it works, and one of the available tweaks,
Again, this info is of no value to you with your existing turn-key solution.
Yes, if an A/C unit has enough BTU then it can overcool a space if you choose to do so. Unless the air coming out of the swamp-cooler is cooler than you'd ever want, then the swamp-cooler won't overcool that space. On the playa, some setups have a swamp-cooler overcooling their space somewhat, so they shut it off, have it on a timer or even a thermostat.
As for using a swamp-cooler on a large space like a bus, the success of doing that would depend on how passively heat resistant the bus is (forget it if lots of unsheilded windows; too large a heat gain, you'd have to be replacing the inside air too often). It's a balance of airflow of chilled swamp-cooler air, which results of a dwell time of that air within the structure as it flows through the structure, against how much heat is incoming to the structure and how much it will heat up the interior air before it is exhausted by fresh chilled incoming air from a swamp-cooler(s). If one's intended use of the bus precludes taking measures to minimize heat gain from the playa, then don't waste your time considering a swamp cooler (you'd need very large, or a number of large units, and you wouldn't be able to know if you got it right until you were on the playa
BUT, a small swamp-cooler can be an additional benefit to add to a bus
(or ____), even though it would not
be doing any meaningful cooling load: would you like to have the interior at a slight positive air pressure to minimize dust getting in while having the incoming swamp cooler air replacing interior dusty air (dust you tracked in and gets into the air) with fresh dust-free air?
A swamp-cooler is not a turn-key solution. You have to built it, install it on the playa (although you could
have it integrated to the bus) and monitor it & add water as required (or use a top off, which has to be monitored). But it has way fewer points of failure, significantly less noise, both inside and against your neighbours, isn't causing wear & tear on A/C or generator that are way more expensive, pushes dusty air out with dust-free air replacing it, while that air is comfortable cool, and happens to cost a fraction of an A/C solution.