Talk:Radiator
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Here are some other facts on how it works: Old cast-iron radiators, very often in Victorian splendor, stand guard over the chills of winter, and many homeowners hate to part with these beauties. Other homes have heating systems that literally disappear beneath the surfaces of the rooms as radiant panels. Just about anything is (and always has been) possible with hydronics.
Older cast-iron radiators, the sort used on "one-pipe" steam heat, have nipples only across the bottom portion of the individual radiator sections because steam is lighter than air. When the steam enters the bottom of a radiator it flows upward into the radiator sections, pushing the air from a vent.
Hot-water radiators, on the other hand, have nipples across both the upper and lower portion of the radiator sections. Even though hot water rises, it doesn't move as quickly as steam. The double set of nipples encourages better circulation of the hot water through the radiator.
Around 1905, when "two-pipe" steam became popular, contractors began to use hot-water radiators on their steam systems as well, and those old steam radiators with their single set of bottom nipples soon became obsolete. Several manufacturers continue to make freestanding cast-iron radiators with the upper and lower push nipples, however.
And some more information on its origins (originally found at http://news.bbc.co.uk/2/hi/europe/4359094.stm):
It is commonly claimed that the Romans invented central heating, but the Samara Heating company did some research which it said showed the radiator itself first appeared in 1855 in the then Russian capital, St Petersburg.
Its inventor, an ethnic German of Italian origin named Franz San-Galli, named it the "hot box" and patented it in Germany and the US.
[edit] Request for Specifics
I generally like this article, but I would appreciate more specifics.
Under "Automobiles," the article states:
"Between the engine and the radiator lies the thermostat, a temperature operated valve. It remains closed, restricting coolant flow, until the engine reaches the thermostat's activation temperature. This arrangement allows the engine temperature to be maintained in the ideal operating range." [Bolding added.]
What is the "ideal operating range" of temperatures? Do different types of engine (e.g. Gasoline, E85, Diesel, Propane/LPG, Natural Gas, Gasoline-Electric Hybrid) have different "ideal operating ranges"?
- For a standard petrol car engine the ideal operating temperature is around 82C. Does anyone know the power transfer capacity of a radiator? I roughly guess that it is 20kW / (80C - 20C) = 340W/K but I can't find any hard figures. --njh 01:21, 10 November 2006 (UTC)
Another point that seems unclear to me: is "ethylene glycol (a.k.a. antifreeze)" added only to ensure cold weather performance, or also to make heat transfer more efficient in any weather?
- I believe that Ethylene glycol and now Propylene glycol are used mainly to stop freezing. Boiling point elevation is more easily done with pressure valves, both chemicals reduce the water's heat capacity and increase the viscosity (reducing the conduction rate). They might help with wetting? --njh 01:21, 10 November 2006 (UTC)
Finally, it would be nice to add citations for the stated facts, as well as sources of additional information.
Thanks in advance for your help.—The preceding unsigned comment was added by 70.48.234.150 (talk • contribs).
- The 'ideal' temperature is a bit misleading, because engine temperature (like so many other engine parameters) is a compromise. A cooler engine will produce more power, while a hotter engine may have lower emissions. This is probably too in-depth for an article about radiators, so I'll change the 'ideal' into 'design' temperature.
- Also, the article seems to refer to the thermostat as either 'open' or 'closed', which isn't correct. The thermostat opens just enough to maintain the engine at the design temperature. How far it opens, depends on many factors (such as outside air temperature, air flow through the radiator and the amount of power (=heat) the engine is producing. I'll incorporate this into the article. -- Rpvdk 08:37, 19 October 2006 (UTC)
[edit] bleeding home radiators
I have hot water baseboard heating and need to bleed the radiators because I hear a lot of gurgling when the heating comes on. Should the heat be turned up or off when I bleed the radiators?Markhoffman 23:27, 1 January 2007 (UTC)
Perhaps not a Wikipedia topic? But always nice to help: Afraid I'm not entirely sure what you mean by 'baseboard' but to purge air from a rad that is always (in theory) water filled, it doesn't matter if the heat is on or off. The rad valve control should be open but ideally have the system pump turned off (goes off when heating is off) - the water pressure will expel the air. On some systems, having the pump on could theoretically cause air to be sucked in rather than expelled...
129.12.200.49 20:38, 3 February 2007 (UTC)
[edit] Convectors in houses are properly called radiators ...
... for the simple reason that if you say "radiator", people will know what you mean and if you say "convector" almost no one will. Good luck finding "convector repair" in the Yellow Pages(TM).
Whether "radiators" actually work by radiation is beside the point. I'll probably fix the article in a spare moment. -Dmh 22:40, 8 January 2007 (UTC)
