Your only going to be able to remove as much heat from your living space as your heat rejection area, your garage floor, can expell. As mentioned above, the concrete holds heat very well. It is not a good heat tranfer medium.
If your plan works at 100% effientcy for some strange reason, then congradulations! The inside of your house will be the same temperature as it is outside!!! You could have just opened all the windows
Now there is a way to achieve coolingwith a plumbed concrete, but you need the a high exhaust point and a low air intake point and the whole building is designed around it. This is to avoid the dampnes. There is no fans involved. Oh and you need a production and injection water well.
Here is a building in penticton i drilled the wells for that is using this technology. At the bottom
http://www.penticton.ca/EN/main/depa...-building.html