TL : DR
Smart Meter gives delayed readings? + Cost of running electric fan heater?
- Thread starter OM2
- Start date
Sponsored Links
- Joined
- 27 Jan 2008
- Messages
- 23,687
- Reaction score
- 2,669
- Location
- Llanfair Caereinion, Nr Welshpool
- Country
I have seem bread many times, what program was Einstein in?
Sponsored Links
- Joined
- 27 Jan 2008
- Messages
- 23,687
- Reaction score
- 2,669
- Location
- Llanfair Caereinion, Nr Welshpool
- Country
I agree in the main, does not matter what resistive method is used. Energy in = energy out. However this
simple cheap heater is not simple resistive, it also sends out infrared energy, this does not heat the air but passes straight through the air, and heats what it is aimed at, it has also many disadvantages, the heat can pass through most windows even if double glazed, and it is hard to automate control. As a result often they have multi bars, so user can select how many bars, and rarely have a built in thermostat.The fan heater also has both advantages and disadvantages like the infrared but not quite as bad, when it turns off, the user feels cool very quickly, and circulating air can mean warm air is pushed past cool surfaces, so with single glazed home more heat is lost through the glass, but it also like the infrared is fast heating the area, plus with a fan heater it can have thermostatic control sensing the heat of the returning air.
Although speed today is an essential part where we don't maintain the rooms at a temperature 24/7, the amount slower that a radiator can heat the room also gives a plus as it cools slower so giving a more constant heat. The water filled radiator supplied from a modulating boiler with a thermostatic radiator valve (TRV) which is electronic, with algorithms so it works out how soon to start heating the room, so it is warm at the time set, is likely the best way to heat the room, as it does not switch off/on but turns up/down so is just warm enough to maintain the room, as long as no other device turns off the boiler, then the boiler will modulate (turn down) also to reflect the demand, and only when down to its minimum setting will it initiate the mark/space ration (turning off and on) to further reduce output.
However the oil filled radiator (with built in thermostat) does have some of the benefits found in the ones supplied from the central heating, it will employ a mark/space ratio to keep the radiator just warm enough to maintain the room, the user is often unaware if using power or not, so does not feel cool immediately when it turns off. So it likely the best compromise.
I have not seem an electric powered oil filled radiator with algorithms built into it so it can be set on a timer to heat the room to a temperature by a set time, I see no reason it could not be built in the same as water type, but not found one. The TRV head with water type costs around £45 and are made in a high quantity. So it would likely add £75 to the cost of an oil filled radiator, which likely explains why the feature is not found.
However what I am saying is not all resistive heaters are the same, energy in = energy out yes, but how it delivers that energy also matters, there is a balance between speed and hysteresis, we don't want it to store too much heat, the storage radiator may have little hysteresis but it also heats the room when not required, and the infrared heater has far too high a hysteresis, and likely the oil filled radiator is the happy medium.
If it's not "simple resistive", what do you think it is - do you think its load includes an inductive or capacitive component?
I think/presume what you're trying to say is that it heats, partially or 'almost completely', by radiation (radiating IR) rather than by convection from a very hot source?
If you're talking about the IR radiation, that passes very poorly through ordinary glass. That's why greenhouses work - the glass lets UV light in, which heats things and hence causes them to radiate IR, but the glass won't let the IR out. You're into photography - if you've ever tried to take an IR photo through ordinary glass, you will know that it is essentially opaque to IR!
Kind Regards, John
agree in the main, does not matter what resistive method is used. Energy in = energy out. However this
I agree, apart from, as pointed out by John above. In fact our first ever electric heater, back in the 50's, was of that IR type as were almost all back then, so nothing new. From what I remember it had two bars, wire wound on some sort of ceramic former, which a massive switch on the rear and portable. It had very exposed live hot parts, just a narrow guard directly in front of the element, and large reflector behind it.
Most, many, all fireplace mounted units are/were of the IR variety, because neither fan nor oil filled would quite fit the bill in a fireplace. I cannot really comment further, not having seen such a heater in the home, for many decades - though I keep a portable version similar to Eric's photo and a couple of fan heaters around for emergencies.
Yep, I also remember them well (might even still have an example in cellar or attic). As you say, almost entirely IR heating, so I also remember us huddled round (very close) in front of it, with scolding hot faces and very cold backs
The elements did, of course, get 'red hot', and therefore could have done some convection heating, but they seemed to almost be designed to minimises the amount of convection that could occur!
We also had, in the 60s, a 'drip feed' paraffin heater, which was conceptually similar, with a wire mesh getting red hot and radiating heat - again, huddles of nearby people with hot fronts and cold backs! The more 'traditional' ('tall') types of paraffin heaters (which we also had) worked almost entirely by convection, since the hot parts (flame) were hardly visible (probably only through a very small inspection window)
Kind Regards, John
For practical purposes yes. Firstly it will be "non-inductively wound" (I suggest you Google it) and secondly, any capacitive or inductive component will change the power factor of the heater. However, as you don't pay for the imaginary power even though it has to be generated (again Google it) any capacitance or inductance in the heater is irrelevant to the amount you pay.
If you're suggesting that such an element will have significant inductive or capacitive reactance at 50Hz, then I disagree.
I know all that, without the need to do any Googling. However, didn't you realise that my question to eric was essentially sarcastically rhetorical? It surely is the case that the load presented by such an element will be almost entirely resistive, with the inductive and capacitive components being negligible at 50Hz - and that would remain the case even if it were not "non-inductively wound".
It seems that eric was trying to make a (valid) point about the difference between radiant and convected heating but for some reason made the statement that radiant heating is "not simply resistive".
Kind Regards, John
As with most things, it's not quite that simple!
Glass is opaque to mid to far IR, but it is quite transparent to near IR:
Although the drop off is quite extreme passed 1700nm (in the short-wave IR)
Flir cameras are sensitive to between 7 and 14µm.
For example, an IR remote control uses a wavelength of 940nm and this will easily pass through the glass panel of a media cabinet (it can also sometimes be viewed on phone cameras!).
Edit:
Just had a play!
IR heaters generally have an output between 500 and 3000nm, so there will be a partial loss of the IR through a window.
...and as for the "Greenhouse effect" in an actual greenhouse (see "Real greenhouses" section)...
Greenhouse effect - Wikipedia
Last edited:
No need, I am familiar with the term.
I have never ever come across a non-inductively wound domestic heater, and seriously doubt there would be a need for such. The inductive component will be miniscule.
Fair enough (and, as you say, few things are 'simple'!!) - I certainly don't claim to be an authority on such matters
Hmmm - well if that's true, it's certainly contrary to everything I've been taught and believed. Also, that presumably could not explain atmospheric/global "greenhouse effect", since I can't see how the presence of greenhouse gases in the upper atmosphere could/would 'reduce convection' (I must see what the wiki has to say about that!)....and as for the "Greenhouse effect" in an actual greenhouse (see "Real greenhouses" section)...
According to Wiki, the effect is due mostly to a reduction in convection. However, there are plenty of other sources that repudiate Woods findings!Greenhouse effect - Wikipedia
en.m.wikipedia.org
Kind Regards, John
- Joined
- 13 Mar 2019
- Messages
- 683
- Reaction score
- 161
- Country
You've surely sat the other side of a window on a sunny day before, so must intuitively know this isn't true.
You mean on the 'other side' from the sun? If so, then it's the UV radiation from the sun which passes easily through the glass and which warms you up (and hence causes you to radiate IR).
Kind Regards, John
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
