Using glycol in closed loops systems
Using glycol in closed loops systems
(OP)
I'm trying to find out how using 30% prop. glycol in my closed loop heating system will effect the output from my boilers, i.e. will I need to increase my boiler output due to the change in specific heat or not? If there is any rule of thumb out there I'd love to hear about that to. Thanks!





RE: Using glycol in closed loops systems
I assume from your post this is an existing system, what are you currently using in the closed loop system? Just water or some other glycol mixture?
RE: Using glycol in closed loops systems
RE: Using glycol in closed loops systems
This translates into a higher thermal resistance. At a fixed flow rate, this means that the delta between the heat source and heat sink must go up, assuming constant energy in.
TTFN
RE: Using glycol in closed loops systems
I suggest you to use the word heater instead of boiler
This link will give you specific heat of glycol solution at various concentrations.
www.lyondell.com/html/products/techlit/2516-V1-0703.pdf
Regards,
RE: Using glycol in closed loops systems
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Regards,
RE: Using glycol in closed loops systems
It is my understanding that boiler and heaters are the same thing, I ussually call heater to the small 30-50gl house hot water heater and other than thet is a boiler to me.
hot water boiler.
ER
RE: Using glycol in closed loops systems
RE: Using glycol in closed loops systems
I have to agree that it does get confusing. In my family home we had a Water Boiler that heated water for circulating hot water for heating. The system was changed out to steam heat and then we had Steam Boiler. Both were made by the same company.
The ususal definition is that in a boiler you allow the liquid, normally a single liquid, to vaporize by supplying the latent heat and providing a means to separate the vapor and liquid.
In a heater there is no attempt to vaporize the liquid and is even prevented from vaporizing. There are also exceptions to this as we have single effect evaporators where the steam chest that boils off water is called a heater instead of a reboiler because the bulk of the feed to the evaporator is only getting heated a few degrees.
The term reboiler is usually reserved for when you are using a heating medium, Steam, Hot Oil, etc, to vaporize a liquid or mixture of liquids. Though you can have reboilers that don’t allow the liquids to boil/vaporize in the reboiler, as on some distillation columns or evaporators.
This can get even confusing in one situation we have. We have direct fired boilers, primary, vaporizing a heating medium (Therminol) which in turn is used to vaporize Therminol in other smaller reboilers, secondary, used to regulate the temperature at specific points in a process. On the primary side we only use the latent heat of the vaporized primary Therminol as the condensate is returned to the primary boilers within a degree or so of the boiling point. In this system there is also a direct fired heater that just heats liquid Therminol which is then allowed to vaporize by means of a flash drum. The heater/flash drum system was installed to have a system with a larger turndown ratio than a vaporizing boiler.
It gets even more confusing as you go from industry to industry and country to country.
RE: Using glycol in closed loops systems
RE: Using glycol in closed loops systems
RE: Using glycol in closed loops systems
In regards to glycol, I design solar systems and use 40% glycol/water and I reduce my heat transfer by 15% to compensate.
RE: Using glycol in closed loops systems
If you have water pumps with packing seals they will begin to leak (quite a bit - like 1 drop every 5 seconds)if you change from 100% water to glycol/water. The circulating pumps must have mechanical shaft seals when using glycol/water.