High Efficiency Electric Heaters

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Hey Guys, been trying to google this answer for a while now, figured I'd post in here but it's been a long time.  Had to reset my password, I forgot it.  What a nice new site too, I kinda miss the brown old site but I'll deal with this... I don't have a choice right?

 

What the heck is the difference between a general purpose electric heater and a high efficiency heater?  According to thermodynamics, energy is conserved and I'd assume that's true no matter what.  Wouldn't any heater have the same efficiency?  If I plugged a resistor into my outlet at home, that should output the same power right?  In fact, most "high efficiency" heaters have an LCD and a fan...  I would think these are less efficient than a general purpose electric heater.  I'm calling a general purpose heater one of these "ceramic" heaters like this

http://www.menards.com/main/heat...

 

I am calling a high efficiency heater one of those big box things with the infrared in the front like this.  You know, the things with the infrared element in the front.

http://www.menards.com/main/heat...

 

Any ideas which is "better"?  Obviously ceramics are far cheaper to purchase.  Does infrared somehow create more heat than ceramic per watt?  No way according to my knowledge of physics.  Is this just a gimmick?  Could I just plug a resistor into my receptacle and get the same amount of heat out assuming the resistor is sized right?   Both heaters come with thermostats and weak little fans.    Ceramic heaters never claim any efficiency while the radiative ones have the word efficient all over their descriptions.  I don't get it at all, maybe someone here could explain it to me.  It's impossible to find an answer to this question on google; all I get is advertisements for buying them.

 

 

 

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Here is another example of something claiming to be "high efficiency" electric heater

 

http://www.globalindustrial.com/...

 

any idea what is going on here?

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I was always led to believe that "radiant" heaters heated the air in a room.

Infrared heaters give out infrared energy that organic objects, like humans, feel as heat - but only when you are in range of it's infrared energy.

I have no idea which is more efficient though. I guess it depends on how you measure the efficacy of the heater.

SpiderKenny
@spiderelectron
www.spider-e.com

 

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170W, 580 BTUs - figure that one out!

I dare say the efficiency is how well it transfers the heat into the surrounding air.

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Ok, that makes more sense, an infrared heater may not be efficient because it shoots the heat into a wall in its line of sight.  A more convective electric heater would keep the heat in the air in front of it local.  That actually makes sense.  I am heating a portion of my garage where I am growing coffee plants (don't ask... wife's idea)  and I want to spend as little money as possible.  I thought about simply hooking nichrome up to a PLC or uC to not even have to spend money but this may just radiate which I assume would just heat a wall to the outside.  Now it makes sense.  We don't want to use propane for the sake of health and such as we spend lots of time in there and we've heard propane heaters give off CO2 and CO and such.

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It wasn't electric, but the heater in my shop was very efficient. Instead of heating the air, it radiated IR. The air would be cool, but I would be warm. This lead to a strange effect: if you're cold, take your sweater off.

The largest known prime number: 282589933-1

In my humble opinion, I'm always right. 

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Russell, I would modify your definition further.

 

"the efficiency is how well it transfers the heat into the" intended target. Take for example an inductive cooktop. Air is not involved, but heating sure is.

Ross McKenzie ValuSoft Melbourne Australia

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What valuesoft says makes me sad as I spent 120 bucks and 4 hours buying and installing 10R (1in with reflective surfaces) insulation panels.  If I don't need to keep the air warm, I could have bought 2 or 3 cheap ceramic heaters and pointed them straight at the root balls and achieved a more cost effective solution.   I have been trying to heat the whole room, what a bad idea in retrospec

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Oh don't take what I say as anything other than an idle mind spinning on a topic.

 

If I was trying to grow coffee in the basement I would be studying the coffee plant more closely before worrying about heating efficiency. Does the plant flourish because its root ball is warm, or because its leaves and trunk are warm, or because of photosynthesis on its leaves or some combination or all three plus 20 others that my ignorant mind knows nothing about. I think more study is required.

 

PS..

 

A quick Google with "growing coffee in a hot house" produced http://gardendrum.com/2013/10/03...

and lots of others. Sounds like lots of work especially in your climate.

 

Surely cheaper to find a supplier of excellent coffee beans.

 

But best of luck.

 

Ross

 

 

Ross McKenzie ValuSoft Melbourne Australia

Last Edited: Tue. Jan 19, 2016 - 12:47 AM
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I found my high pressure sodium lamps generated enough heat to keep my horticulture experiment warm. I had to get hazardous area rated ones as I get explosive fumes from my lab experiments :)

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Haha yah, I am growing the coffee in the outdoor barn.  We get really cold in the winter like you pointed out.  My heater went dead and the room dropped to like 50 degrees!  

 

The reason for the coffee is me and my wife went to Costa Rica two years ago for our honeymoon and they have a brand of coffee over there called Cafe Brit.  We went to the area where they do the roasting and we grabbed a bunch of seeds and we went to another coffee place and had to get a bunch more seeds.  We had to sneak them onto the airplane and sneak them through customs.  We then brought them home and got some sprouted and our birds ate most of the seedlings!  We have two surviving coffee plants as basically the only memory of this trip besides our photos and a tee shirt my wife trashed in the gym.  Anyways, yah it gets too cold, I want to find a high tech low cost solution to this problem.  No where good in the house to grow these guys, basement ceiling is very low so we can't do it there.  In the house, a ballast with a light bulb would look really bad I guess.  I have 240 in the barn and it was the perfect place in the summer but now that winter is finally here, it is the cold which I am battling.  I put up the insulation and started buying heaters, they stink.  I don't want to have lights running in the house for all of eternity, the barn is just ideal (except for the frigid cold which has just beset me).  I'm going to get a Flir sent up from the headquarters pretty soon and see if I can insulate the room better or I am going to focus on a precision heating regimen.  Maybe some RTDs placed on the planters and some well aimed cheapo heaters.  Maybe wrapping the roots in a nichrome heating wire or something low cost.  

 

Only about another month or two to worry about this problem then I will be probably worrying about air conditioning a hot room!  We aren't doing this for the monetary gain, that's for sure.  Maybe we are going to start growing hops also to fully utilize the wasted light but that will be next month after we get the bee hives set up!

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I don't think it is wise admitting you possess and illegally imported plant matter on an open forum!

http://www.cbp.gov/travel/clearing-cbp/bringing-agricultural-products-united-states

If it were me, I'd be expecting a knock at the door.

 

As for heating:

https://en.wikipedia.org/wiki/Trace_heating

 

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Most of what I have read about growing in cold weather, stresses keeping the soil warm. Warming the air just allows the surrounding cold air to move in and displace it. No gain. Small waterproof heaters in the soil or wrapped around the pot and insulation wrapped around that would work. Soil moisture will evaporate much faster, so a moisture sensor and automatic watering might be needed. Very efficient.

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Kartman wrote:

I don't think it is wise admitting you possess and illegally imported plant matter on an open forum!

http://www.cbp.gov/travel/clearing-cbp/bringing-agricultural-products-united-states

If it were me, I'd be expecting a knock at the door.

 

As for heating:

https://en.wikipedia.org/wiki/Trace_heating

 

 

Don't worry: SWAT teams usually don't knock.

The largest known prime number: 282589933-1

In my humble opinion, I'm always right. 

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I ought to stay out of this, as I've created some absolutely terrible designs, thermally, over the years...

 

Torby's comment also made me laugh.

When responding to civil unrest, (riots), or shoot out in progress, (think bank robbery gone bad, etc), no warrants and no knocking are involved.

When serving high risk warrants, a "no-knock" warrant is pretty darn rare in my experience.

Other locations, other Judges, might operate differently.

 

Back to the subject at hand.

 

I would have thought the goal was to bring the "room" / enclosure / "mini-greenhouse" up to a stable temperature.

If one heats the plant's pot, and the air is cold, the pot will just radiate its heat to the air.

If one heats the air or the plant, and the pot and the table are cold, the pot and the table will be warmed by the heat in the air.

If the walls are poorly insulated, and the air and the plant and the pot are warm, they will just heat the walls...  (radiation, conduction, etc.)

 

Your goal, I would think, is to reach a steady state temperature within the growing environment.

 

The insulation on the walls is to slow the heat (energy) loss to the outer environment, and to contain the heat within the desired region.

 

We use a small 120V ceramic heater in the back of the helicopters when they are at the base to help keep the interior of the cabin warm, and hence also keep the drugs and batteries for all of the equipment warm.

Aircraft are light weigh and thin walled and lose heat to the environment easily, so it is a losing battle, but still overall effective in the main task.

 

I think, also, you will need to research the lighting requirements for your plants.

Think "grow lights", etc.

 

I neither grow, nor drink, coffee, but it will be interesting to see how your project progresses!

 

JC

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Around here we use heat pumps.  It is often more efficient to move heat with electric driven compressor.  The reversing valve swaps the condenser/evaporator flow so they will heat or cool.  Greater efficiency is possible with geothermal or large thermal storage pool.

It all starts with a mental vision.