However, last clubnight mentioned a an interesting coolant, stating (I think) that this could be used instead of water in bikes' cooling systems to avoid boil-over when idling at traffic lights for example.
I turned to Strongbow and asked if it had the same thermal capacity as water and replied 'Yeah'. ~Well it doesn't. But at the time I didn't know better. My mind was blown, the only substance I knew of which had a higher thermal capacity than water was lithium, but apparently this coolant doesn't need water?!!
This has been playing on my mind so I cracked out my old cooling system notes from college and had a read through to try and refresh.
I've attached a whitepaper about a coolant additive ( Red Line Water Wetter ) which covers a lot of the theory which is quite interesting.
It goes on to say the differences in thermal conductivity between water, 50/50 and using WaterWetter and how quickly they could cool a material.
with WaterWetter required 3.2 seconds, water alone 3.7 sec, 50/50 glycol in water required 10.2 sec, and 100% glycol required 21 sec. Water alone required 15% longer, 50/50 glycol 220% longer, and 100% glycol required 550% longer.
And the effects different pressures on the cooling system can have.
. The boiling
point of water treated with Red Line using a 15 psi cap is 250°F compared to 265°F at 15 psi for 50% glycol. Increasing the pressure by 50% to 23 psi will increase the boiling point of water to 265°F
Water's great at what it does but it's key drawback is it's boiling point is below the optimum internal running temperature of the engine. It's problem is when water vaporises it loses its immense ability to absorb heat.
Redline's WaterWetter is an additive you can put into your 50/50 mix which significantly improves coolant's ability to transfer heat away from vital components by lowering the percentage of water which vaporises in the system, especially in pressurised systems.
Unfortunately although this product is amazing and worth using if you run a 50/50 mix it's not boil-over proof if you are sitting at the traffic lights or bogged down revving hard. So I did some Googling to try and find out more about this stuff that doesn't boil over!
Evan's Waterless Coolant, the coolant I think was mentioned at club night, is a newer technology. It's a synthetic liquid which has a boiling temperature of 180° and because it doesn't contain water, the fluid will not vaporise on contact with high temperature components like the cylinder head.
This means that, even though water has higher thermal conductivity, at high temperatures is where it excels in transferring heat away from the engine.
The hotter a material the faster rate at which heat is transfered. I.E. A radiator that is 121°C will dissipate up to 25% more heat than one at 104°C. So this has significant benefits over a conventional 50/50 mix and as long as you don't have your rads off frequently it would be well worth the investment.
Some considerations for using Evans:
+ Evans Waterless coolant is WAYYYY better than running a conventional 50/50 mix due to it's heat conductivity at high temperatures.
+ It doesn't boil over.
+ It has no water and therefore doesn't corrode components
+ Less pressure in the system at temps above 100°C
- It is more viscous so it requires more energy to pump and it will not circulate as quickly.
- Also it's lower thermal capacity means it's capacity to store energy in the form of heat from the engine and transfer it to the radiator will be lower; less thermodynamically efficient.
- The system must be completely flushed with a hygroscopic fluid first.
*A thermostatically controlled cooling system will self-regulate to stabilize the temperature based on the setting of the thermostat. But if your system doesn't have good enough flow rate might you be in trouble.
*Optimum engine running temps are important to prevent wear of vital components and achieve a good burn.
I'm undecided if I'm going to use Evans coolant myself but it looks good to me!
People who have the luxury of a rad' fan might be better off sticking with additives to have the best of both worlds.
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Thermal Capacity:
The measurable physical quantity that specifies the amount of heat energy required to change the temperature of an object or body by a given amount.
Thermal Conductivity:
The property of a material to conduct heat, specifically the rate at which it does so.
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