RichConley
Attack of the Killer Cute
It really doesnt matter. Theres only one place for the heat to go, and thats into the water, so the transfer efficiency/surface area really makes little difference.
-
******* To read about the changes to the marketplace click here
Heater physics question
- Thread starter Liam
- Start date
It really doesnt matter. Theres only one place for the heat to go, and thats into the water, so the transfer efficiency/surface area really makes little difference.
Yes.
Jim
Jim
clamm
Nothing to nobody
Isn't there a short spike in current draw during the transistion from off to on. If thats the case then its more efficient to run 1 because the transisition time would be less.
However, I really doubt this difference would show up on an electric bill.
I agree with others the best effort and bang for the buck when trying to increase heater efficiency is to get the ambient heat off the tube as quickly as possible. AKA...flow/circulation around the heater area.
However, I really doubt this difference would show up on an electric bill.
I agree with others the best effort and bang for the buck when trying to increase heater efficiency is to get the ambient heat off the tube as quickly as possible. AKA...flow/circulation around the heater area.
>Try not to be controversial. Not 100% electricity is turned into heat. A small fraction of the electricity is turned into magnetic field<
Okay. For my own curiosity, what % of the electricity are we talking about with an AC heater than ends up as a magnetic field? 0.1%, 1%, 10%?
Okay. For my own curiosity, what % of the electricity are we talking about with an AC heater than ends up as a magnetic field? 0.1%, 1%, 10%?
clamm
Nothing to nobody
if memory serves it can be calculated given the wattage and inductance of the heater element (coil). Its been a while...and I don't have the formula. I wouldn't think it would be too much.
Looks like there is more to it then that...here is a good site that describes how to calculate magnetic fields.
http://www.vias.org/physics/bk4_07_03.html
Looks like there is more to it then that...here is a good site that describes how to calculate magnetic fields.
http://www.vias.org/physics/bk4_07_03.html
Last edited:
I would be suprised if the heaters had any ferrous metal in them.
Jim
Jim
RichConley
Attack of the Killer Cute
Casey, even with that spike, its still all (well, probably 90%+) converted into heat, so it really doesnt matter.
As to getting heat off the tube, it doesnt matter. If the heat comes off the tube slower, the tube is just going to stay on a little longer than needed, and then slowly add heat. Longer heat transmission time is going to basically keep the heater from flicking on and off.
A heater thats better insulated is going to come on longer, but stay off longer. It still transmits heat when its off until it comes back down to the ambient temperature.
You guys are way overthinking this, it doesnt matter in any sort of practical way. Run 2 smaller heaters for safety reasons.
MarkO
...
Guys, arent we talking pennies here?
If you want to save money, heat the tank with lights, pumps and ballasts. It can be done. I prolly save $20 a month not using a heater at all.
I'm thinking of relocating my tank into a sunroom (which I need to build first
) and cutting back on artificial lighting, possibly eliminating it. If Calfo can propagate corals in Pittsburgh with no supplemental lighting, why not here?
If you want to save money, heat the tank with lights, pumps and ballasts. It can be done. I prolly save $20 a month not using a heater at all.
I'm thinking of relocating my tank into a sunroom (which I need to build first
) and cutting back on artificial lighting, possibly eliminating it. If Calfo can propagate corals in Pittsburgh with no supplemental lighting, why not here?
dave601m
Non-member
I like the idea of using lights to heat the tank: For the winter,I just shut down my cooling fan on the lights. I have 2x40's over a 16 bow, and now the heater only needs to run at night and a tiny bit during the day (room temp is stable 62). Tank is wrapped on two sides with fiberglass insulation. In summer, I'll take off the insulation and turn back on the fan. This is the first full month I've done it this way, and the tank is tiny anyways, but I'm still curious to see my elec bill, and if it helped at all.
I also insulated my 29 gal freshwater (which is in a nearly unheated room ~55degrees, so i expect huge savings here) And my 46 bow (normal output lights, Fish only). Between the three, I'm hoping for at least a 10 dollar per month drop.
I also insulated my 29 gal freshwater (which is in a nearly unheated room ~55degrees, so i expect huge savings here) And my 46 bow (normal output lights, Fish only). Between the three, I'm hoping for at least a 10 dollar per month drop.
Be careful about turning off you lights fan. It's not just about blowing warm air away from your tank but keeping the bulbs cool as well. Bulb temperature plays a big part in how long your bulbs (especially fluorescents) will last.
Ultimately, reducing the extra "wasted" heating energy for your tank in the winter isn't going to save you as much as you might think since the extra heat is just going to end up heating the room that the tank is in so your home heat doesn't have to work as hard. Sure, electrical energy is more expensive than say gas or oil but in the end you're probably only looking as something that's on the order of pennies vs. dollars/month. Managing heat in the summer time is a whole different story when you have AC fighting it out with an 80 degree tank with hundreds of watts of lighting all day.
Ultimately, reducing the extra "wasted" heating energy for your tank in the winter isn't going to save you as much as you might think since the extra heat is just going to end up heating the room that the tank is in so your home heat doesn't have to work as hard. Sure, electrical energy is more expensive than say gas or oil but in the end you're probably only looking as something that's on the order of pennies vs. dollars/month. Managing heat in the summer time is a whole different story when you have AC fighting it out with an 80 degree tank with hundreds of watts of lighting all day.
Fingolfin
Humble Christian
That's a good question. Without knowing the resistance/thermal resistance/coil diamter/number of turns of the heater, it's very difficult to estimate.
And you don't need ferrite core to generate the magnetic field. The purpose of ferrite is to serve as a reservoir of magnetic field. In this case, you really do not want to use ferrite in the heater core because it will reduce the amount of electricity converted into the thermal energy.
In the electrical engineering world, we call it Q factor.
Q = 2*pi*f*L/R.
where f is the operating frequency, L is the inductance, and R is the resistance.
Q factor represents the ratio of the energy stored versus energy dissipated when the electrical field passes a given device. In our heater application, we want a low Q device, i.e. minimum magnetic energy gets stored in the coil, and maximum electric energy gets dissipated, which is in this case turns into heat. Adding the ferrite to the core will only elevate the Q factor.
MarkO is right, we are talking about pennies here.
Actually, I got this crazy idea: what we should really do is to design a water proof case to hold the metal Hallide ballast then drop it in the tank. It would turn into a natural heater. Once the water temperature hits the target, you raise the ballast from the water. With some clever mechanical robot design, we can even automate it. The problem is that it won't work at all during the halide down time. Anyway, just a thought.
dave601m
Non-member
That is true - I didn't tihnk of shortening bulb life. The bulbs are still touchable because the hood is still vented - though they are definitely warmer. With the fan on, they're darn near room temperature, with out the fan, I can still grab one wiht my hand and not get burned.
As far as heating goes - the house is a constant 62 degrees, and has been since October when we fired up our heat. I agree with you that it won't make a huge difference in my two salt water tanks because it'll just reduce the furnace load - but our 29 is in an unheated room, so that won't affect the furnace, and it's a difference of about 78 degrees (tank) to about 55(room). That's where I'm hoping the savings will come into play most. 24 hrs a day/7 days a week of not having to have as much heat loss out of that tank should help.
As far as heating goes - the house is a constant 62 degrees, and has been since October when we fired up our heat. I agree with you that it won't make a huge difference in my two salt water tanks because it'll just reduce the furnace load - but our 29 is in an unheated room, so that won't affect the furnace, and it's a difference of about 78 degrees (tank) to about 55(room). That's where I'm hoping the savings will come into play most. 24 hrs a day/7 days a week of not having to have as much heat loss out of that tank should help.
That's a tough one with the tank in the unheated room. The >20 degree difference across the glass is a killer. If you could insulate that somehow, you'd probably see a big difference. Even a piece of cardboard when and where you don't need to see in would help. My Marco Rock curing tank in the basement is wrapped on 3 sides with cardboard (the box the rock came in to be exact) - 75G with one small heater and it stays at 80 no problem. There are also pieces on the top but that doesn't really fly for an actual live tank that needs lights.
dave601m
Non-member
it is insulated now, when I first moved it into that room, the 200W heater couldn't keep it above 72. I wrapped 3 sides and the top in extruded polystyrene insulation and some fiberglass behind it (a bit ugly, but effective). the next day the temp was up to 76 which is where i want it, and I'm sure the electric meter was spinning much slower. I can only imagine I must have had that poor 200W heater on at least 20 hrs a day if it couldn't even keep the tank up to the right temperature. I should have my electric bill this week to see if it actually helped 
clamm
Nothing to nobody
MarkO
...
Heh,
I guess it is what we do. I know I've got that penny wise pound foolish logic. I'm just trying to think outside the box here. My last months elec. bill was $260.00
OK, part of it was my Christmas lights, but still, that's almost exactly double what I paid in rent back in college.
Aquaman_68
too many gadgets to fail
Just to put the titanium heater oxidation to rest. I've been using titanium heaters for over 10 years (same one) No oxide yet!!!!!! As far as heaters & numbers!!!! It depends on the tank length. If you have 4 feet or better two heaters would be more effecient to tranfer the heat more even throughout the tank. (provided there is ample current & they are postioned in the right locations) Liam, FWIW...You need to start crunching numbers from the mfg on their listed usage ratings. That is how I purchase all my equipment & have been doing so from a very early stage in the hobby. You want to cut down on electric? Look in the area of pumps & lighting!!! Two of the biggest areas of consumption!!! BTW...Fans in a canopy are very very useful!!!!!
