It is Jan.25 and, though not the coldest day that my system is in direct sun, It is 25 deg. F outside and the solar loop of my Evacuated Tube system is at 110 deg. at 12:40 PM Plus, One question... Will I need to have a heat dump in the summer? I ran the system in late sept. and oct. with no issues. The heat exchanger tank is 40 gal. and directly tied to the 38 gal oil hot water heater.. There are 2 sections of the solar loop that are not insulated in a crawl space. This is aprox. 18 - 20 feet of 3/4 in copper not insulated. This is a 40 tube system.

as additional information, I should state that we have well water and it is usually 50 - 55 deg. F. The 40 gallon tank solar tank has a heat exchanger inside of it and it is connected to my 38 gallon oil fired hot water heater. Which, on sunny days, does not have to come on.... The thing that bothers me most in the winter time is the solar tank will be up past 95 deg F and then through the night it is chilled by the solar loop to keep it from freezing... I guess I could have looked into a drain back type of set up to lessen this waist of solar energy...

Your losses (including the freeze control losses) are primarily in your uninsulated piping that runs through the crawl space, not the insulated parts that run outside!  It needs to be the same high-temp stuff that's used on the rest of the solar run, but INSULATE IT ALREADY!

As for heat dumping- it' depends.  If it looks like it's going to be running hot and you're willing to fiddle with it, rotating some or all of the evacuated tubes to minimize solar gain isn't usually a huge task.  If you don't want to or can't, maybe...  your max gain period will likely be near the summer solstice (June 20ish), so your September performance isn't particularly relevant...