transient heat transfer from borehole pipe to ground
 

hi everyone i am simulating a borehole thermal storage , 4 u pipe that are connecting to each other in series form , each of them are 42 m deep in ground (ground is cylinder in 50 m diameter and 60 meter depth ) and water flows in them , i am trying to calculate how much heat is dumped and extracted from ground in a whole year , the inlet temperature is calculated by udf from the calculated outlet temp and the building load and heat pump cop , now my question is this : since the flow in pipes are converged within 5 times steps and i want to simulate a large domain of ground in a whole year is it okay to make the time step as big as 3600 secs ?
note that my building load is hourly .

I wanted to chime in on your post about simulating a borehole thermal storage system. I don't know much about this kind of work. But now I'm applying to be an engineer, and I think that in a couple of years I'll be able to know more about this kind of work. But maybe experts will already be able to give me some advice?

Your project sounds really interesting! I think it's great that you're trying to calculate how much heat is dumped and extracted from the ground in a whole year. I'm not an expert in thermal simulations, but I think using smaller time steps is generally advisable for more accurate results. However, I understand that simulating a large domain of ground for a whole year can be computationally expensive. You might want to look into api 8c inspection services and maybe speak to a professional. Anyway, if you've done some testing and found that a time step of 3600 seconds gives you acceptable results, then it should be okay to use it.