If the earth temperature is typically cooler in TX, as it is here in MN (about 45F year around), you may want to consider pouring your slab on top of 2" foam sheets. This will provide a thermal break and your slab will not be cool to humid air, condensing moisture. Pouring over a 4mil plastic sheating also creates a moisture barrier so the slab does not draw up ground moisture. Pouring over either tends to really slow down setup time and, as such, is not popular with some concrete finishers.
Unless you have something going on in your building that will be creating humidity, I can't see where any type of ventilation system will do anything for you. To the contrary, if the outdoor air is humid, you'll just be pulling humid air into the building. If you don't have any thermal break between your slab and the ground, then that humid air will be continually condensing on the slab as the air is being changed by the ventilation.
An insulated building will go along way to prolonging the life of your equipment, even if you don't heat or A/C the structure. We bought a foreclosure a few years ago for a second home, as my bride took a job 150 miles from our primary home. It had a two car attached garage that was uninsulated. It would stay, at best, maybe 10 or 15 degrees warmer than the outside air in the winter. The only real benefit it had in the winter was not having to scrape frost off the glass in the morning or brush snow off. In the summer, that garage was a sauna and in the dog days of summer was probably 20 degrees or more hotter than the outdoor temp, from the heat being generated by the roof. Those temperature extremes are really hard on equipment. For example, high temperatures cause plastics to age more rapidly and become brittle. We insulated the garage, sheetrocked, taped and painted it. We also added an overhead heater that we only utilized when working in the garage. The garage was typically a minimum of 30 degree warmer than the outside air in the winter, without operating the heater, and near the same temp or cooler than the outdoor air in the summer. The insulation alone made a huge difference. At a minimum, I suggest you research the cost to insulate the ceiling/roof.