Theoretically, the heat transfer from air in underground pipes to ground is possible.
Practically, as Moontanman pointed out, moisture removal is the problem, as well as pipe sizes, and air quality.
What you are trying to do is essentially geothermal system.I would suggest researching water cooled geothermal system. See, e.g.,
http://www.climatemaster.com/index/r...eothermal+Heat.
Instead of running loops of 18" steel pipes to supply 1750 CFM of air, underground; you may want to run 1" copper water loop. It is much cheaper.
If indeed the ground temp is 53deg F, then the system may work. The water coil in the fan will remove moisturesufficiently , I believe. (Instead of collecting moisture in underground pipes.) Water system is also less susceptible to bad air quality, since air is controlled within the house environment.
(Hire an Engineer to design it, whatever you decide to do.)
