Forums

Forums
Renewable Heating
Air Source Heat Pum...
Are antifreeze valv...
 
Notifications
Clear all

Are antifreeze valves essential for a glycol free ASHP system?

 
Page 1 / 2
Air Source Heat Pumps (ASHPs)
Last Post by AllyFish 2 years ago
20 Posts
8 Users
16 Reactions
5,567 Views
RSS
 Mike H
(@mike-h)
Reputable Member Member
Joined: 4 years ago
Posts: 200
Topic starter 13/02/2024 11:04 am  

During a recent upgrade to my 12kW Samsung ASHP set up, the glycol was removed as requested. I expected one or more antifreeze valves to be fitted, but I was told on good authority that these were not required. So I wondered if anyone had any views on the pros and cons of fitting antifreeze valves? If fitted, is one on the return flow sufficient or should there be one on the leaving flow too? Is anyone in the same position, having no glycol and no antifreeze valves?

I must admit to feeling a little anxious when all occupants of our three terraced cottages were away at the same time after Christmas, when it went very cold and any power cuts would have gone unnoticed!



   
👍
1
Quote
Mars
 Mars
(@editor)
Illustrious Member Admin
Joined: 5 years ago
Posts: 3805
13/02/2024 5:21 pm  

Great question. @heacol will know the answer.


Get a copy of The Ultimate Guide to Heat Pumps

Subscribe and follow our YouTube channel!


   
ReplyQuote
 Brendon Uys
(@heacol)
Noble Member Contributor
Joined: 4 years ago
Posts: 415
13/02/2024 5:39 pm  

According to Samsung, you either have to have antifreeze valves or glycol. As glycol will add 20%+ to your heating bill, it is not really an option. In reality, if you want top install them, 1 will suffice on the lower pipe, however, it is nearly impossible for ice to damage the Samsung unit as the internal connecting pipes are rubber, and will expand on freezing. 

It is up to you, I have about 600 units in the field, of all makes, and no glycol or antifreeze valves, and have not, in the last 15 years, had a single unit damaged by ice.

 



   
👍
1
ReplyQuote



 Mike H
(@mike-h)
Reputable Member Member
Joined: 4 years ago
Posts: 200
Topic starter 13/02/2024 10:39 pm  

@heacol Thanks Brendon, that is very helpful.



   
👍
1
ReplyQuote
Mars
 Mars
(@editor)
Illustrious Member Admin
Joined: 5 years ago
Posts: 3805
14/02/2024 9:09 pm  

@heacol I’ve also wondered how that worked. Will the system remain protected if there’s a big winter storm with temperatures below zero and power lines get taken down, and we’re without power for a few days. Wouldn’t that do some damage and wouldn’t stuff that shouldn’t freeze, freeze?


Get a copy of The Ultimate Guide to Heat Pumps

Subscribe and follow our YouTube channel!


   
ReplyQuote
 Brendon Uys
(@heacol)
Noble Member Contributor
Joined: 4 years ago
Posts: 415
15/02/2024 7:32 am  

@editor I am not saying the units will not freeze in some conditions, and I have seen many, however it is the design of the unit it'self that will determine if there is any damage. Units that have standard circulator pumps in them such as Valiant, Midea/Clivet and others are vulnerable as standard circulators can easily be damaged by freezing, some units with pumps like Panasonic are not affected as they have taken the time and effort to make their own pump. Units that have no pump, like Samsung and Mitsubishi, are not usually affected.

As I said, it is your choice. My choice is Panasonic hands down, it is so far ahead of the pack for many, many reasons.



   
ReplyQuote
Abernyte
 Abernyte
(@abernyte)
Honorable Member Member
Joined: 3 years ago
Posts: 247
15/02/2024 7:59 am  

Posted by: @heacol
↑

As glycol will add 20%+ to your heating bill,

Really? That is an enormous claim, citation required.  I am aware of talk around a small increase,  but 20% plus ( by how much plus) is astonishing.



   
ReplyQuote
 David I
(@david-i)
Active Member Member
Joined: 2 years ago
Posts: 4
16/02/2024 8:29 am  

@abernyte Difficult to get specific figures but I work on

Water 4.184kj/kg.K. 

Monopropylene glycol 3.884kj/kg.K (@30%)

Monoethylene glycol 3.712kj/kg.K. (@30%)

Pump at say 50W will cost 1p/hour to run, with glycol added 1.1p/hr.


I work for a manufacturer of heat pumps and boilers.


   
👍
1
ReplyQuote
Mars
 Mars
(@editor)
Illustrious Member Admin
Joined: 5 years ago
Posts: 3805
16/02/2024 8:36 am  

@david-i interesting. Thanks for sharing. So do you avoid glycol in systems too?


Get a copy of The Ultimate Guide to Heat Pumps

Subscribe and follow our YouTube channel!


   
ReplyQuote



Toodles
 Toodles
(@toodles)
Illustrious Member Contributor
Joined: 3 years ago
Posts: 2327
16/02/2024 10:08 am  

@editor No Glycol in our Daikin installation but we do have two antifreeze valves. When the ‘Boss’ came to do a little ‘snagging’, he was surprised (and I think, a little miffed due to their cost) that his installers had fitted them in both pipes rather than just one. I was rather pleased that they had fitted them in both as surely, if the pipes are both very cold, isn’t better that they both drain? (Or is not how this precaution is supposed to work perhaps?). (Daikin are coming today to carry out the first annual service) Regards, Toodles.


Toodles, heats his home with cold draughts and cooks food with magnets.


   
👍
1
ReplyQuote
 AllyFish
(@allyfish)
Noble Member Contributor
Joined: 3 years ago
Posts: 516
16/02/2024 11:25 am  

Anti-freeze valves provide some guarantee of a fail safe if the system is unpowered for a long period and all other forms of frost protection such as the unit pump circulating water and/or frost protection heating in the circuit fail. You are into double jeopardy however - a long power failure coincident with extreme prolonged low temperatures. Anti-freeze valves should be on both outdoor unit supply and return pipes at the lowest point. Glycol isn't really required in the UK provided external pipework is properly insulated and protected.

Glycol lowers the specific heat of water with increasing concentration, it's the renewable parallel of adding hydrogen gas to mains gas methane, which lowers the calorific value of the resulting blend. That's why using H2 for domestic heating is a dumb idea, aside from the cost of producing it and the safety issues it creates.



   
👍
3
ReplyQuote
Abernyte
 Abernyte
(@abernyte)
Honorable Member Member
Joined: 3 years ago
Posts: 247
16/02/2024 11:58 am  

Which does not get us anywhere near a 20% plus energy cost increase caused by using glycol.



   
👍
1
ReplyQuote
Page 1 / 2
Forum Jump:
  Previous Topic
Next Topic  



Share:

Join Us!

Podcast Picks

Latest Posts

Click to access the login or register cheese
x Powerful Protection for WordPress, from Shield Security
This Site Is Protected By
ShieldPRO →