ques regarding anitfreeze in a home heating hot water loop

[danny burstein]

Hi there.

I've asked three of the local Licensed and Insured Professional HVAC companies here and gotten an "err, umm, well.." response from them. Hence my post here to anyone still around.

The situation is that we've got a boiler (Lochinvar, if that matters..) that we installed about five years ago, replacing the old one and saving us plenty thanks to its much higher efficiency.

However, we've run into a problem (not directly related to the boiler).

One heating zone goes to a bathroom in the garage (the rest of the garage is unheated). We're in a _cold_ winter zone and what happened last year (20 degrees F below zero..) was that:

The house is well insulated. The garage isn't.

So the house got to 70 degrees and the thermostat shut off the boiler and the water pump.

It took (numbers made up here) an hour before the house dropped two degrees and the thermostat kicked back on. However, the garage, bathroom, and the heating loop there... froze a _lot_ sooner.

This led to the pipe in the garage bathroom freezing and cracking, and we know the rest of that story.

(Fortunately not tooooo much water damage).

Anyway, our plumber replaced that whole section of pipe with a brand new SlantFin segment.

The Licensed and Insured company suggested one way to prevent this in the future was to replace the water in the loop with..

--- ANTIFREEZE ---

Simple enough and makes sense. But then I asked the question that stumped him and two other local groups:

Is the antifreeze solution less effective at heat transfer, and if so, will this mean we'll be burning more fuel?

About two decades ago I spec'ed out a water cooled air conditioning system. (This was going to be inside a completely inaccessable interior room, so the only plausable way to cool it down was with a water cooled unit).

The spec sheets described the various options, but since we couldn't use a "once through" we looked at the various outdoor radiator cooling choices.

The info sheets had the various figures, BUT said that if using antifreeze, to derate the numbers by ten percent.

So... anyone know if this is still the case today, and if we'd have to make allowances for a hot water boiler?

Thanks muchly

_____________________________________________________ Knowledge may be power, but communications is the key [e-mail] [to foil spammers, my address has been double rot-13 encoded]

[PaxPerPoten]

On 9/7/2015 8:21 PM, danny burstein wrote: > Hi there. > > I've asked three of the local Licensed and Insured > Professional HVAC companies here and gotten an > "err, umm, well.." response from them. Hence my > post here to anyone still around. > > The situation is that we've got a boiler (Lochinvar, > if that matters..) that we installed about five years > ago, replacing the old one and saving us plenty thanks > to its much higher efficiency. > > However, we've run into a problem (not directly > related to the boiler). > > One heating zone goes to a bathroom in the garage (the > rest of the garage is unheated). We're in a _cold_ winter > zone and what happened last year (20 degrees F below zero..) > was that: > > The house is well insulated. The garage isn't. > > So the house got to 70 degrees and the thermostat > shut off the boiler and the water pump. > > It took (numbers made up here) an hour before the > house dropped two degrees and the thermostat kicked > back on. However, the garage, bathroom, and the > heating loop there... froze a _lot_ sooner. > > This led to the pipe in the garage bathroom freezing > and cracking, and we know the rest of that story. > > (Fortunately not tooooo much water damage). > > Anyway, our plumber replaced that whole section > of pipe with a brand new SlantFin segment.

If it is just pipe... It can be replaced with PX pipe that will not break when frozen. > > The Licensed and Insured company suggested one > way to prevent this in the future was to > replace the water in the loop with.. > > --- ANTIFREEZE ---

Actually the chemical placed in hydronic systems is a bit more then just antifreeze. regular antifreeze is extremely poisonous. Many hydronic systems have automatic feed water systems that top off the system when pressure falls..So that it never runs dry. That feed water comes from the domestic drinking water. While there is a one way valve in the system.. There can be some leakage back into the drinking water system. Thus possibly poisoning your drinking water. Also the chemical used enhances heat transfer and resists algae etc during non-heating seasons. Please confer with you contractor for solutions that best fit your system. > > Simple enough and makes sense. But then I asked the > question that stumped him and two other local groups: > > Is the antifreeze solution less effective at heat transfer, > and if so, will this mean we'll be burning more fuel?

The proper chemical made to be used in Hydronic systems will enhance heat transfer. The savings in actual heat dollars will be fairly small. Do not use Automotive Antifreeze in that system. > > About two decades ago I spec'ed out a water cooled > air conditioning system. (This was going to be inside > a completely inaccessable interior room, so the only > plausable way to cool it down was with a water cooled unit). > > The spec sheets described the various options, but since > we couldn't use a "once through" we looked at the > various outdoor radiator cooling choices. > > The info sheets had the various figures, BUT said that > if using antifreeze, to derate the numbers by ten percent.

Must have been a closed loop system...But 10% loss is a ridiculous wild assed guess. Do you really think the antifreeze in your automobile actually is less efficient at cooling(heat transfer) then water? Standard automotive antifreeze is actually a better transfer coolant then pure water. Do keep in mind that any chemical or antifreeze will eventually break down due to aging and decomposition from heat etc. Thus should be replace at timely intervals. > > So... anyone know if this is still the case today, and > if we'd have to make allowances for a hot water boiler? > > Thanks muchly > > _____________________________________________________ > Knowledge may be power, but communications is the key > [e-mail] > [to foil spammers, my address has been double rot-13 encoded]

[amdx]

Take a look at this Google search, several of these forums, figure out which ones are active and fit your topic, and ask your question.

I suspect most of them are going to have your answer. There are non hazardous antifreeze solutions.

Mikek