methanol seems to be the best in transfering heat and is the cheapest by far. i am waiting on a reply from a seller who uses glycol or ethanol as to wether he will use methanol instead. meth seems to get a bad rap when infact it is used the most as in your windshield washer fluid and every plane is deiced with it. glycol is used in prestone antifreeze and if you have a pet you know not to leave it around or they will lap it all up and of course die from kidney failure. dogs love the sweet taste of it. ethanol is a known carcinogen and does not evaporate like meth does ... well it will eventually but unlike meth with has a very fast evap rate. so does anyone use it and like it. meth over a 20 yr life span is significantly more cost effective than glycol also.

glycol is far less flammable. Ethanol and methanol are very dangerous during the filling process.

ethanol and methanol add no viscosity. Gasoline is highly flamamble during the filling proccess in your truck.
Eric

methanol is great and IMHO is the best for cost and vicosity (low temp) reasons . If pre-miked offsite, there is no flammability issues when on a customer site.

methanol is what we use, but I must correct one thing rik, glycol used in geo is food grad and non poisonous.
j

ethanol is a known carcinogen

Only if you are drinking your antifreeze. There is no measurable or expected carcinogenic burden from ethanol exposure in the workplace or in use as heat transfer liquid in geothermal heat pump systems.

I asked for my system to be filled with Methanol. It is working great. The loop calcs always favor Meth over glycol from what I saw. Glycol gets very viscous at low temps, but any system can be designed to work with either.

I have a two stage system with two loop pumps. I only run one pump on first stage and two on second stage. If I had glycol, I would not get enough flow with this set-up and would need to run both pumps all the time. This pumping energy adds up and should be considered in your overall system running costs. You may want to check if the pumping energy is included in the calcs. The Climatemaster calcs I got initially did not include the actual loop pumping energy. If I recall, each 26-99 Grunfos uses about 300 watts.

My system runs on 1st stage probably like 95% of the time, so Meth is saving me money. Only certain systems/loop combos will likely be able to take advantage of this 1/ 2 pump staging.

Some local codes do not permit Meth to be used as it is considered toxic. I don't really understand that as I hear it will neutralize and dissipate if there was a leak.

Good Luck!

For those that have experiance with the glycol based products.

Is there really a bacteria or goop that grows in the loop if the mixture is to little or exposed to something? Some of the waterfurnace literature mentions it briefly.
Eric

univ. of WI did a study and found you develop more leaks with glycol , less with ehtanol and none with methanol in geothermal. they are the ones stating that eth is a carcinogen in the study. it is long study but i think i saved it. if anyone wants to read it . i will post the url.

Please post the url. I find fault with the fluid type having anything to do with the frequency of leaks/ quality of fusion.
Eric

Having serviced glycol filled Amana HTMs I have seen this stuff leak out of virtually every gasket sealed joint.
While never through fusion joints, boiler men and geo guys have seen crusted up flow centers from this same seepage.
j

It may be from the University of New Mexico.

To get it, stick the exact phrase, below, in your Google and run it. The updated summary is the one with "AN UPDATE" in the title and the original study with all the gory details is the ASHRAE Research Project #908 link.

ANTI-FREEZE FLUID ENVIRONMENTAL AND HEALTH EVALUATION

If Ethanol is a carcinogen, then I'm done for...

My evening beverage of choice routinely contains 5-9% of the stuff!

Posted By acwizard on 07 Jul 2011 03:33 AM
glycol is far less flammable. Ethanol and methanol are very dangerous during the filling process.

Why not just use Coke or Pepsi, non-toxic and very refreshing.

Not once have I caught fire during my own evening "filling process"

Posted By waterpirate on 08 Jul 2011 06:31 AM
For those that have experiance with the glycol based products.

Is there really a bacteria or goop that grows in the loop if the mixture is to little or exposed to something? Some of the waterfurnace literature mentions it briefly.
Eric

Seen the slimy result of bacterial growth in loops...it was nasty! Plus you loose the antifreeze properties! And yes, gasoline is as dangerous to handle.

http://rp.ashrae.biz/page/rp-908.pdf that should take you to the study.

Methanol, It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor. Because of its toxic properties, methanol is frequently used as a denaturant additive for ethanol manufactured for industrial uses.

Ethanol, Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a solvent, and as a fuel. In common usage, it is often referred to simply as alcohol or spirits. It has a long history as a fuel for heat and light, and more recently as a fuel for internal combustion engines.