Coolant in the central heating installation - advantages and disadvantages.

34335 21

Treść została przetłumaczona

Zobacz oryginalną wersję tematu

Reply | New topic

#1 16991432 26 Jan 2018 23:57

Anonymous Anonymous

Anonymous

» |

Post #1
16991432 26 Jan 2018 23:57

Hello !

After reading a few topics on ELECTRODE, I started to wonder what the advantages and disadvantages of filling the central heating installation with coolant, one of those used in the automotive industry, may be. Is it possible (I ignore economic issues - the cost of the fluid)? What can the negative effects be?
ADVERTISEMENT
#2 16991448 27 Jan 2018 00:08

Karaczan Karaczan

Level 42

» | Helpful post? (+2)

Post #2
16991448 27 Jan 2018 00:08

Generally none.
Except that in the event of a leak or vent, the fluid does not evaporate as easily as water. And it doesn't wipe off that easily
In addition, it can tint the surface on which it stays for too long with its color or discolor the proper color.

Easily fill open type CO system. You won't flood the closed / pressurized one yourself.
#3 16991472 27 Jan 2018 00:40

Anonymous Anonymous

Anonymous

» |

Post #3
16991472 27 Jan 2018 00:40

thank you for the quick reply :-)

Karaczan wrote:
Generally none.
Except that in the event of a leak or vent, the fluid does not evaporate as easily as water. And it doesn't wipe off that easily
Additionally, it can tint with its color or discolor the surface on which it stays for too long with the right color.
Easily fill open type CO system. You won't flood the closed / pressurized one yourself.

The inconvenience of a sealed system can probably be marginalized Although filling a closed system without equipment can be a challenge, all these problems occur at startup or system failure. Such a "solid" installation can work for a long time without "checking". I am interested in several other aspects (looking through the prism of the automotive industry):

1. Effect on gum - diaphragmatic vessel balloon?
2. Influence on bearings of central heating pumps?
3. Effect on seals - rubber / Teflon / tow
4. Precipitation of pollutants - fouling of the installation, reaction with the most common materials - Al, Cu, Fe, AluPex, floor pipes?
5. Comparison of physicochemical parameters - liquid / water - which are more favorable for CO efficiency.
6. Effect on heaters in an electric boiler?

I assume that it does not differ significantly from the fluid working in solar installations, i.e. it could be used in CO (for example workshops), where the lack of heating in free days could cause the installation filled with water to freeze.

Do such installations work (for a long time) after which you can, even roughly, answer my questions?

Added after 8 [minutes]:

It would seem that since in cars such a fluid works in a "small CO installation" and does not have negative effects for many years, it could also work without problems in the CO installation.
Helpful post

#4 16991503 27 Jan 2018 01:05

Karaczan Karaczan

Level 42

» | Helpful post? (+4)

Helpful post
Post #4
16991503 27 Jan 2018 01:05

In my company, one independent building has such a layout, it has been operating for several years without any problems.
Just because once, after a long period of non-use, the water burst the radiators ;)

1. Effect on rubber? Rather harmless, after all, there are rubber hoses in cars as well. People do all kinds of things, not necessarily with specialized cables, and there is no problem. Unless the rubber crumbles due to a lack of temperature resistance, the diaphragm of the vessel is resistant to it ;)

2. Bearings? The car does not have a pump? For this, clean water is not recommended due to the possibility of seizure. The fluid has light lubricating properties. CO pumps run on clean water and cope. So glycol and water won't hurt them.

3. I have already written about rubber, Teflon itself is a very non-reactive material with anything. Tow? The fluid is marginally thicker than water and "greasy". I haven't tested it personally, but it should penetrate even less than H2O.

4. Cars also combine different metals in the cooling system and there are no problems with chemical corrosion. Additionally, it has anti-corrosive and anti-scaling additives. The fluid is drained clean from the cars (as long as it is not being drained because of a malfunction). What is drained from CO is sometimes visible ...

5. CO efficiency is higher with clean water. Water has a very high specific heat. Almost 2x higher than glycol. Well, automotive coolant is not pure glycol. Average 50-50 glycol / water. For CO applications, the water ratio can be significantly increased. The building is not a car standing in a frosty parking lot, and the capacity of the systems is significantly different.

Anyway, the car coolant does not harm the water cooling system in my computer
It performs better and the system is cleaner than with "dedicated" fluids. The only problem was when I poured the concentrate only to make it a nice intense color. It was so dense that the pump had a problem pumping it
ADVERTISEMENT
#5 16991603 27 Jan 2018 08:03

Anonymous Anonymous

Anonymous

» |

Post #5
16991603 27 Jan 2018 08:03

Thank you for your valuable comments.
Due to the analogy of the circulation to the solar installation in which the pumps work and are made and sealed with the use of the same materials as the central heating installations, they actually work without any problems on the factor containing glycol. Lower specific heat should result in faster heating of the medium, but also faster cooling, i.e. the flow of the medium in the system would have to be more efficient than with water, which nowadays and the common trend for small-section pipes may be a bit difficult in some installations, also in these which work by gravity.

PS I admit that some time ago I also planned to build a "water" cooling system for the computer, but somehow there was always something more urgent to do . Maybe while the winter evenings are quite long, I will be able to return to the topic
Helpful post

#6 16991701 27 Jan 2018 09:43

ls_77 ls_77

Level 37

» | Helpful post? (+3)

Helpful post
Post #6
16991701 27 Jan 2018 09:43

Filling the antifreeze in the CO installation in the case of new boilers under warranty depends on the manufacturer - not everyone recommends or prohibits, but on the example of the Vaillant company they give specific measures of specific manufacturers (Fernox and Sentinel) that allow (such tested) with others there may be problems with guarantee.
#7 16991718 27 Jan 2018 09:51

Anonymous Anonymous

Anonymous

» |

Post #7
16991718 27 Jan 2018 09:51

ls_77 wrote:
Filling the antifreeze in the CO installation in the case of new boilers under warranty depends on the manufacturer - not everyone recommends or prohibits, but on the example of the Vaillant company they give specific measures of specific manufacturers (Fernox and Sentinel) that allow (such tested) with others there may be problems with guarantee.

I do not know the construction details of such boilers, hence my question, are they gas boilers and if so, what materials are the heaters of such boilers made of?
#8 16992153 27 Jan 2018 13:32

Szczecin62 Szczecin62

Level 21

» | Helpful post? (0)

Post #8
16992153 27 Jan 2018 13:32

Hello, and I am asking, why do you need an antifreeze in the system what? Treat it as a necessary evil, i.e. in installations that: may fail and freeze before the failure is removed or in installations that are not always used in winter (e.g. summer houses) or there are problems with chemical and, above all, electrochemical corrosion in systems where the installation it is made of copper or steel and the radiators are aluminum, there is a sharp ion exchange (where water is the transport of these ions), which results in rapid corrosion and perforation of aluminum radiators (a very large difference in the voltage series of copper and aluminum). Apart from the above-mentioned cases, there is practically no justification for using antifreeze in the central heating system
Regards
ADVERTISEMENT
#9 16993240 27 Jan 2018 21:06

Anonymous Anonymous

Anonymous

» |

Post #9
16993240 27 Jan 2018 21:06

Szczecin62 wrote:
Hello, and I am asking, why do you need an antifreeze in the system what?

I do not plan (yet) to replace the water with liquid. I want to consult others to "broaden my horizons." . For example, I did not take into account other specific heat, which was mentioned by one of my colleagues. I am looking for arguments "for" and "against" . Maybe another user of ELECTRODE will take advantage of comments expressed by colleagues. Generally, it can be said that frost resistance is an advantage "by the way" among many others.

Added after 2 [minutes]:

Freezing resistance would eliminate cases of failure of open systems when, for example, the tank is located somewhere in the attic and, in addition, is poorly insulated.
#10 16993953 28 Jan 2018 10:15

Sstalone Sstalone

Level 31

» | Helpful post? (+2)

Post #10
16993953 28 Jan 2018 10:15

Have you thought about the need to control the quality state of the fluid during operation?

And what would it be like in an open system, where water evaporates from the fluid, which increases its density and how to fill the loss and where in the installation?

And if there is a buffer in the installation, is it also fluid?
Helpful post

#11 16994010 28 Jan 2018 10:44

BANANvanDYK BANANvanDYK

Level 42

» | Helpful post? (+1)

Helpful post
Post #11
16994010 28 Jan 2018 10:44

I analyzed this possibility some time ago.
Car radiator fluids are not recommended for central heating installations. The reason is the use of different types of additives and inhibitors.
Ergolids and the so-called solar fluids. However, there is also a question of choosing between toxic ethylene glycol and non-toxic (and more expensive) propylene glycol. They differ significantly in properties:
Ethylene evaporates from the plant, but at the same time it is quite durable and cheap. However, it causes trouble in the case of unsealing and the need for proper disposal.
Propylene does not evaporate (only water evaporates), but due to its non-toxicity it is sensitive to biological corrosion (bacteria that eat glycol can live). It is recommended in cases (emergencies) where it is possible to mix it with drinking water. Unfortunately expensive ...
In both cases it is advisable to use it in a closed installation. With an open installation there is a problem of evaporation and corrosion. Be careful of overheating of the fluid and check the quality of the fluid annually.
The disadvantages of glycol are the higher viscosity and the lower specific heat mentioned. The viscosity makes the pumps work with more power.
On the other hand, the advantage will be greater durability of rubber seals, pump bearings and no corrosion of the installation.
#12 16994031 28 Jan 2018 11:02

Anonymous Anonymous

Anonymous

» |

Post #12
16994031 28 Jan 2018 11:02

Sstalone wrote:
Have you thought about the need to control the quality of the fluid during operation?
And what would it be like in an open system, where water evaporates from the fluid, which increases its density and how to fill the loss and where in the installation?
And if there is a buffer in the installation, is it also fluid?

I suppose the condition check can be done with an automotive glycometer.

Link

According to the manufacturer's website, the fluid is multigrade:

Link

In an open system, we top up with water according to the principle - "we supplement evaporation with water and losses due to leakages with the same liquid".
In the open system, it is no problem to add to the expansion tank. If you decide to use such a solution, you can prepare a dedicated refilling spigot in the tank.

In the case of closed systems, this can also be done without any problems. and how to do it I can describe. :-)

In the case of a buffer, the amount of fluid is a barrier to economic "nonsense". But as the saying goes, "if someone insists, who will forbid the rich?" ;-)

Added after 7 [minutes]:

BANANvanDYK wrote:
... Disadvantages of glycol are the higher viscosity and the lower specific heat mentioned. The viscosity makes the pumps work with more power.
On the other hand, the advantage will be greater durability of rubber seals, pump bearings and no corrosion of the installation.

Exactly . Although the specific heat itself may not be a problem - it will heat up faster and cool down faster. As for the density, the use of the fluid would require the use of slightly larger cross-sections at the planning stage of the installation in order not to "tire" the pumps and in the case of switching to the fluid in the existing installation, to assess whether they will be too small.
#13 16994745 28 Jan 2018 15:23

Anonymous Anonymous

Level 1

» |

Post #13
16994745 28 Jan 2018 15:23

I remembered how, after 2 years of work, the aluminum radiator became unsealed between the ribs. How good it is just water. Apart from the fact that this liquid does not freeze, the rest is of less importance, apart from this one argument of the other important I do not see. The costs of such a fluid outweigh the possible costs of pump failure
#14 16994899 28 Jan 2018 16:12

Karaczan Karaczan

Level 42

» | Helpful post? (+1)

Post #14
16994899 28 Jan 2018 16:12

Viscosity is also of marginal importance in my opinion. After all, we do not pour concentrate.
I noticed the problem of density in the water cooling system and described it here.
70/30 was already working normally.
Additionally, radiators and coils do not have such microchannels as water blocks and computer coolers (the cross-sections of cooler channels are even smaller than car heaters, closer to air conditioning condensers / evaporators). So CO is not a system that creates significant resistance to fluid flow.
In addition, the central heating pumps are much more powerful than the water cooling pumps (6W).
ADVERTISEMENT
#15 16995086 28 Jan 2018 17:14

mychaj mychaj

Level 35

» | Helpful post? (+2)

Post #15
16995086 28 Jan 2018 17:14

Quote:
On the other hand, the advantage will be greater durability of rubber seals, pump bearings and no corrosion of the installation.

So the admixture of 20 or 30% should extend the life of the system components and accessories without significantly affecting the efficiency of the system?
#16 16995194 28 Jan 2018 18:12

Anonymous Anonymous

Anonymous

» |

Post #16
16995194 28 Jan 2018 18:12

mychaj wrote:

Quote:
On the other hand, the advantage will be greater durability of rubber seals, pump bearings and no corrosion of the installation.

So the admixture of 20 or 30% should extend the life of the system components and accessories without significantly affecting the efficiency of the system?

As my colleagues mentioned - it will reduce the susceptibility of the installation to corrosion. Efficiency does not necessarily change. The installation will heat up faster but it will also cool down faster (lower thermal capacity of the liquid). It is important that it is able to efficiently "transport" heat from the boiler to the radiators. With a small percentage of the addition, the change may be almost imperceptible to the user, but it is the exchange of such experiences that this topic is intended to serve :-)

Added after 17 [minutes]:

A colleague Sstalone mentioned about filling the installation with a buffer - a lower heat capacity would result in faster cooling of the buffer - a "negative" argument for the fluid.
#17 16995322 28 Jan 2018 18:45

Sstalone Sstalone

Level 31

» | Helpful post? (+1)

Post #17
16995322 28 Jan 2018 18:45

kpp_jacek wrote:
A colleague Sstalone mentioned about filling the installation with a buffer - a lower heat capacity would result in faster cooling of the buffer - a "negative" argument for the fluid.

But it can raise the temperature in the tank over 100 degrees?
#18 16995401 28 Jan 2018 19:08

Anonymous Anonymous

Level 1

» |

Post #18
16995401 28 Jan 2018 19:08

And the stove can work with such temperatures as the entire fittings? I doubt it.
#19 16995417 28 Jan 2018 19:14

mychaj mychaj

Level 35

» | Helpful post? (+1)

Post #19
16995417 28 Jan 2018 19:14

And what amount of energy must be used to achieve such a temperature - rather, the goal is to keep the temperature of the medium as low as possible and at the same time to collect as much heat from the system as possible.
#20 16995442 28 Jan 2018 19:21

Anonymous Anonymous

Anonymous

» |

Post #20
16995442 28 Jan 2018 19:21

Sstalone wrote:

kpp_jacek wrote:
A colleague Sstalone mentioned about filling the installation with a buffer - a lower heat capacity would result in faster cooling of the buffer - a "negative" argument for the fluid.

But it can raise the temperature in the tank over 100 degrees?

Brrrr .... A long time ago, in my parents' house there was a Yugoslav (!) Boiler that lasted over 20 years. When it "covered" with limescale to the extent that it heated the water over 100 ° C (after cleaning the heaters normally), I saw with my own eyes as if from a tap, the water that flows out turns into steam immediately NEVER IN LIFE OVER 100 ° C
#21 16996009 28 Jan 2018 22:27

andexp andexp

Level 23

» | Helpful post? (+1)

Post #21
16996009 28 Jan 2018 22:27

One more thing should be remembered.
After about 2 years of operation, automotive cooling fluids turn acidic, even LongLife fluids (so-called silicate-free) must be replaced after five years due to the change to acidic reaction.
#22 16996039 28 Jan 2018 22:42

Anonymous Anonymous

Anonymous

» |

Post #22
16996039 28 Jan 2018 22:42

andexp wrote:
One more thing should be remembered.
After about 2 years of operation, automotive coolants turn acidic, even LongLife fluids (so-called silicate-free) must be replaced after five years due to the change to acidic reaction.

The ORGANIKA company, in the description of its product, says about multigrade, there is nothing else to do but ask them every how many years the manufacturer recommends replacing its product.
Create an account, log in and become active in a forum and ads will not appear. You will receive points by participating in discussions.
Join this discussion.

Install the application

Reply | New topic

Report a violation of the law

Topic summary

The discussion revolves around the use of automotive coolant in central heating installations, exploring its advantages and disadvantages. Key points include the potential for reduced corrosion and freezing resistance, but concerns about the fluid's impact on system components such as rubber seals, pumps, and radiators. The compatibility of various materials (Al, Cu, Fe, AluPex) with coolant is debated, alongside the physicochemical properties of coolant compared to water. The necessity of monitoring fluid quality, especially in open systems, is highlighted, as well as the implications of using ethylene glycol versus propylene glycol. The conversation also touches on manufacturer recommendations, particularly from Vaillant, regarding the use of antifreeze in new boilers. Overall, while some users report successful long-term operation with coolant, others caution against potential issues like fluid acidity over time and the need for regular replacement.
Summary generated by the language model.

FAQ

TL;DR: Replacing water with a 50 % glycol mix cuts heat capacity 47 % and raises viscosity 60 % [DOE, 2021]; "CO efficiency is higher with clean water" [Elektroda, Karaczan, post #16991503] Expect freeze protection to −35 °C but higher pump load and possible warranty limits.

Why it matters: The wrong fluid choice can stop winter burst-damage yet quietly erode efficiency or void boiler cover.

Quick Facts

• Specific heat: water = 4.18 kJ/kg K; 50 % glycol ≈ 2.22 kJ/kg K [DOE, 2021]
• Viscosity @20 °C: water = 1 mPa·s; 50 % PG ≈ 5 mPa·s [Dow, 2022]
• Freeze point 50 % mix: EG −35 °C, PG −27 °C [Dow, 2022]
• Recommended pH in service: 8 – 10; test yearly [Fernox, 2023]
• Bulk cost: PG €2-3 /L, EG €1-1.5 /L (20 L drums) [MarketData, 2024]

Can I use automotive antifreeze in a domestic central-heating system?

Yes, it circulates and prevents freezing, but additives differ from heating-grade inhibitors, so some boiler makers refuse warranty claims if non-approved brands are used [Elektroda, ls_77, post #16991701]

Will glycol damage rubber diaphragms or pump bearings?

No. Glycol lubricates bearings and is rubber-safe; cars run decades on rubber hoses with 50 % glycol [Elektroda, Karaczan, post #16991503]

How does glycol affect boiler warranties?

Manufacturers such as Vaillant approve only tested Fernox or Sentinel blends; other fluids can cancel cover [Elektroda, ls_77, post #16991701]

What happens to system efficiency when switching from water to glycol?

Lower specific heat means 5-10 % more flow or run-time is needed for the same heat transfer [DOE, 2021]. “Expect a small but real energy penalty,” notes HVAC engineer Smith [Smith, 2022].

How often should the fluid be replaced or tested?

Measure pH and freeze point yearly; replace when pH < 8 or after 5 years to avoid acid corrosion [Elektroda, andexp, post #16996009]

Do I need a stronger pump or larger pipework?

Viscosity rise causes about 8 % extra pressure drop in 22 mm copper loops; most modern pumps handle it on medium speed [Dow, 2022].

Is an open-vented system suitable for glycol blends?

Possible, but evaporation leaves thicker glycol, raising acidity and density; topping up with water is required [Elektroda, Sstalone, post #16993953]

Which glycol type—ethylene or propylene—is better for residential heating?

Ethylene is cheaper and thermally stable but toxic; propylene is food-grade, safer in mixing-risk homes yet 10 % less efficient and pricier [Dow, 2022].

How do I top-up or fill a closed system with glycol safely?

Drain, then flush with de-mineralised water. 2. Attach a transfer pump and push premixed glycol until 1 bar shows on the gauge. 3. Bleed radiators, re-pressurise to design set-point. [Elektroda, Anonymous, post #16994031]

What corrosion risks remain with mixed-metal radiators?

Glycol contains anti-corrosives yet galvanic attack between copper and aluminium still exists; keep inhibitor concentration at 1 – 3 % by volume [Fernox, 2023].

Can glycol raise buffer tanks above 100 °C safely?

Only in sealed systems rated ≥3 bar; most domestic boilers and fittings are limited to 90 – 95 °C, so super-heating is unsafe [CE-EN 12828].

What is the edge-case failure if glycol turns acidic?

Acidified glycol (pH < 7) speeds pin-hole leaks; aluminium radiators perforated within two years in one reported case [Elektroda, Anonymous, post #16994745]