Not sure if I'm reading your 'sealed room' idea correctly. I presume you will be venting the air conditioner and the 4 in 1 'air conditioner'? That 'water cooler' is more of a personal cooling effect device. Using water to cool air is a great idea - and its what I call a
swamp cooler - I have one on my house and it requires outside air moving over water soaked mats - the air is then routed into the house. It can reduce the outside air temp by about 25F. It requires dry air to work properly since in high humidity water doesn't evaporate as readily. Since I live in a high desert climate I can use it for 3-4 months of the year - and I do. Its working as I type this to cool my home - and ventilate the grow room. The 'waste' air pushes through my grow room and outside.
With that water cooler It a closed room the air would get saturated with humidity and any cooling effect will be lost. Get too much humidity in your grow room and you'll be fighting molds and mildews. Real plant killers. Ventilation is your friend when it comes to grow rooms.
You can't NOT have any ventilation - a truly closed room won't work. So...since you NEED outside air to make your air conditioner work - and the 'water cooler' won't likely do what you wish why not use the cool outside air to remove the heat? Its your cheapest option IMO.
Heat has to go somewhere. In as cool a climate as you live you're cheapest option is to use the cool climate you live in to your advantage and pull in the cooling air needed to cool the grow area then run it through a carbon filter and back outside. You will need outside air regardless of the 'sealed' room - heat will build up and depending on the lights you use - fast or slow - but it will build up.