Just the nature of A/C if you have near 30 coming out, the evaporator is likely lower than 30, almost has to be, at least near the expansion valve. And it will freeze up quick. A cubic yard of air (which the fan will push through right quick) can contain an ounce of water. You'll be producing a lot of water/ice that will lower or plug the airflow through the evaporator or shut the thermostat down right quick.
Another side affect, that many people ignore, is the really low humidity after the water is removed from the air. It will give you headaches and nose bleeds.
There are actually humidifiers to replace the moisture, even in automotive A/C's being produced
Your better off, increasing the volumn of air and keeping the air a little warmer than you'd think. Around 50 actually works well. Most automotive A/C's have a hard time lowering the temp 15-20 degrees, from the outside temp. But a larger volumn of cooled air, works just as well as a lower volumn of colder air.
Automotive A/C's usually cycle on and off, in a fairly short cycle. Using three or four controls, the *thermostat* (keeps the evaporator from freezing up), *low pressure switch* (which is multi function, but one of the functions is to keep the evaporator saturated in freon (along with the *expansion valve*). And sometimes a *high pressure switch*.
The nature of the beast, is that between say 80 and a 100 plus, where you'd use an A/C, the freon is pretty near the limits of it's designed parameters (at least on the high pressure side, the heat produced by the compressor, plus the outside heat, equals near the limit of it's design envelope).
The expansion valve, the HP (or watts or pumped volumn of the compressor) and the evaporator, along with the condensor are a set and the tables for the match are almost a century old. The biggest problem with an automotive unit, is the RPM's of the pump are constantly changing (and the volumn of pumped freon). At anything above idle there is a lot of waste going on, but really no controls for the volumn pumped, except turning the pump on and off.
A larger or faster fan for the evaporator could be benefitial. The next thing to try would be a slighter larger orifice in the expansion valve, along with increased air flow. If liquid freon ever finds it's way back to the compressor, bad things happen, so if you increase the freon flow to the evaporator, you have to increase the size or efficiency of the evaporator and/or the air flow through it. Without freezing the whole works shut. And/or possibly damaging the compressor.
I'm skeptical of an A/C unit producing 30 degree air and working well.
Clear as Mud?
