Posted by dances_with_barkadas on September 13, 2007, 11:46 am
> Nice units, wish we had condensing hot-water heaters here in the
> states.
ok, fine; just be careful of what else might get condensed. Say for
example, depending upon your fuel, amounts of sulphuric acid.
Posted by News on September 5, 2007, 4:53 am
> Also, they are required to be equipped with a pilot light sensor
> (generally using a thermocouple) which turns off BOTH and main burner
> valve and the pilot light gas feed if the pilot light were to be
> extinguished for any reason. The same is true for gas operated home
> furnaces.
In Europe pilotless ignition is pretty well the norm. Pilot only comes in
when the burner is called.
> Some states is the US also require a gas water heater to be equipped
> with a "vacuum breaker" valve on the water feed line, which allow air
> to enter the tank if a negative pressure were to develop in the water
> supply line. This can happen if a fire developes in the neighborhood,
> and the fire department is heavily pumping from nearby fire hydrants.
An anti-vacuum valve can be anywhere on the tank. Why on the incoming cold
mains pipe?
Posted by Don Young on September 5, 2007, 9:56 pm
>> Also, they are required to be equipped with a pilot light sensor
>> (generally using a thermocouple) which turns off BOTH and main burner
>> valve and the pilot light gas feed if the pilot light were to be
>> extinguished for any reason. The same is true for gas operated home
>> furnaces.
> In Europe pilotless ignition is pretty well the norm. Pilot only comes in
> when the burner is called.
>> Some states is the US also require a gas water heater to be equipped
>> with a "vacuum breaker" valve on the water feed line, which allow air
>> to enter the tank if a negative pressure were to develop in the water
>> supply line. This can happen if a fire developes in the neighborhood,
>> and the fire department is heavily pumping from nearby fire hydrants.
> An anti-vacuum valve can be anywhere on the tank. Why on the incoming cold
> mains pipe?
I would think it's to prevent siphoning of water from any part of the
househould plumbing back into the municipal supply lines.
Don Young
Posted by News on September 6, 2007, 8:47 am
>>
>>
>>> Also, they are required to be equipped with a pilot light sensor
>>> (generally using a thermocouple) which turns off BOTH and main burner
>>> valve and the pilot light gas feed if the pilot light were to be
>>> extinguished for any reason. The same is true for gas operated home
>>> furnaces.
>>
>> In Europe pilotless ignition is pretty well the norm. Pilot only comes
>> in when the burner is called.
>>
>>> Some states is the US also require a gas water heater to be equipped
>>> with a "vacuum breaker" valve on the water feed line, which allow air
>>> to enter the tank if a negative pressure were to develop in the water
>>> supply line. This can happen if a fire developes in the neighborhood,
>>> and the fire department is heavily pumping from nearby fire hydrants.
>>
>> An anti-vacuum valve can be anywhere on the tank. Why on the incoming
>> cold mains pipe?
> I would think it's to prevent siphoning of water from any part of the
> househould plumbing back into the municipal supply lines.
> Don Young
The correct way is a check valve on the incoming supply and an anti-siphon
valve at the top of the tank. If the check valve passed and a fire engine
sucked the water out of the house, the tank could implode. The anti-vacuum
valve prevents imploding.
I think this "vacuum breaker", creates an air gap so prevents the water
being sucked out of the tank if the check valve fails.
>
Posted by Jeff on September 1, 2007, 8:23 pm
dances_with_barkadas@yahoo.com wrote:
> reference:
>
> http://www.engineeringtoolbox.com/hydrogen-d_976.html
>
>
> Hydrogen has more than triple the heat-storage-capacity of water.
That would be in in weight, not volume.
Now calculate out out how many cubic feet of hydrogen it takes to
weigh the same as 1/3 cubic foot of water. Last time I checked water was
a lot heavier than hydrogen.
Jeff
> Safe storage of H2 in cylinders is a standard technology. But I don't
> see it being used for heat storage.
>
> Why not?
>
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> states.