Heating installation

[pipedesign]

I have two simple questions :

1. Is there a simple way to determin the volume of water witch is put in a heating installation (installation that contains copper pipes, aluminium radiators and some FCU) ?
Are there any values like : 20 liters of water per 1000W of instaled heating, or something like that ?
2. Is it ok if I use water mixted with glicol (antigel) so my water wont freez inside the pipes during a period when my instalation isn't working ? Is it expensive ? How many times do I have to change the mixture ?

Thank you very much ! It will realy help me if you could answer my questions ! Thanks again !

 

[TBP]

In Imperial measurement terms, if you assume a 20*F temperature drop on a hot water heating system, then a circulation rate of 1 USGPM will deliver 10,000 BTU/hr. If you want a higher delta-T, then you can circulate less water, or a lower delta-T, then you must circulate more.

Glycol can be added for those systems that could normally be exposed to freezing conditions, like intake air coils, remote locations where there could be a power failure or snowmelt. Normally, it's un-necessary. There's quite a large flywheel effect from the mass of hot water in the system, and it probably would have to be out of service for at least a day before freezing would be an issue. Glycol also requires some consideration, as the heat transfer is reduced, and there's the need to check the mixture yearly. It can degrade into the corrosive range. It's easily dealt with, but someone must remember to do it. This often gets overlooked. In addition, glycol will leak where water won't. Unless you really need glycol, avoid it.

 

[pipedesign]

Thanks a lot !
Your info helped a lot !

 

[stoov1]

If it is the VOLUME of water (GALLONS) in a hydronic system you are after not the GPM or flow rate, the best way is to take the linear feet of pipe in the system and find the volume based on diameter. Tables can be found in any piping handbook. This is the only acurate way because there is a dissonnect between the VOLUME of water in a hydronic system and the heating capacity of the system. Because things like distance between boiler and fine tubes and pump vary between designs. You need to add heat exchanger volume and air separators. and other coils. If you need preliminary estimates of header lines you can estimate the gpm as stated in the above response then find the size pipe you need to keep the velocity below 6 feet per second.

Glycol can be used at different concentrations to provide protection at different temperatures (talk to the Manufacturers). But, you may want to consider heat tape or steam tracing the pipe. The glycol solution should last for a long time if you have a closed system, but the system management should be in a preventative maintenance program. Larger systems have this automated but nothing is fool proof or simple. DO NOT provide an automatic refill in a Glycol system if the Glycol is not added at the same time. This can cause a dilution of the system and you can be vulnerable to freezing. Hope this helps

 

[pipedesign]

Thank you ! Yes it helps a lot !!!