Physicist's (slot) fire

I was looking around at making my fireplace use as efficient as possible and came across this:
http://www.texasfireframe.com/

Looks interesting...Does anyone have any experience with this contraption?  This was put forth as something better than a heat reflector, and better burning.

Further interesting-ness:  It got a write-up in time magazine:

http://www.time.com/time/magazine/article/0,9171,879592,00.html

And from some other dude, talking also to a book written by the creator:

http://grandpappy.info/bfire.htm

Also interesting:  The "Grate Wall of Fire"

http://www.gratewalloffire.com/

I just wish these things weren't so expensive! (True of the one slot fire one too)...

I see the common theme of trying to expose the coals to the front of the fireplace to maximize heat output.  Very interesting!

how about you do a rumford and not have to pay so much?

I've seen a little bit about that...  How is that accomplished?  I have a new-ish Magestic pre-fab fireplace, which looks a little bit like diagrams I've seen of the rumford design with the angled sides, but I don't know how it compares to the shallowness and choked flue design...

I am going to have to ask Erica to answer this question. mostly cause she can do english to english translation.

however i am going to try.
the angles of a rumford are such that the radiant heat is not blocked by the sides of the fire place. the breast and smoke shelf allow the fire place to only draft when in use by making a sort of air lock the throat is narrow and 2/3rds the width of the fire place to help accomplish this. your insert is most likely almost set up properly if it is post 1990. so all you really have to do is add a layer of brick to the back of it to get the insert to function like a rumford because the inserts have close to the correct angles but tend to be deeper then is good.
its easy to try cause all you need are bricks and you can stack them with no morter.  when you have a configuration that works right you will notice a few things. 1: the wood will burn completely with a very fine ash. 2: the heat will be able to be felt in a wide fan shaped area at about 10 feet. (most folks dont notice it beyond that distance but if you think about it you can feel a rumford at twenty feet; its darn near magical.) 3: when there is no fire you wont have any draft (this is assuming you are doing the throat as well as the fireplace area). 4: your fire wont smoke out the room. (expect the smoke out when you are trying diffrent configurations and take precautions).

remember this is fire and it asks that we be attentive and safe with it. the price of ignoring the safety precautions can be steep.

How much more are these than ordinary fire grates?

dont know Bubba how much are used bricks?

I would bet cheaper than the manufactured fire grate.

Here's a pic of the Rumford style fireplace angles:
http://www.carbon-pros.com/image/rumford-icon.jpg
from way down the page at http://carbon-pros.com/blog1/personal/

The 2 things I'd add to Ernie's explanation (ask for more re-explanations if you need them):

1) How do you know your heat is getting into the room? 
Think of the heat being sent out perpendicular to the flat walls.  (It's re-radiated in all directions, but as a rough average this is pretty workable).
So you arrange it so that from where the walls meet at the back corner, the perpendicular "swath" radiated by each brick wall does not run into the opposite corner, but beams out into the room.

2) Coal exposure:
There are a lot more ways to make a fire than stacking it in a grate.
The way I've seen Ernie make fires in a Rumford fireplace, time and time again, is to stack the wood in a V, like one corner of a split-rail fence, with the point of the V at the center of the back wall. 

If they burn too quick at the center, you can shove 'em further in from the cold ends.  But they generally burn pretty efficiently, not much smoke wasted, and many of the coals fall down into the center of the V instead of being hidden behind the wood.

If you think of the fire being placed at the focus of your reflector, instead of blocking itself, the heat-beaming properties are amplified amazingly.  And it heats that back wall (the "rounded breast") which in turn makes the draft excellent. 

You can get by with a smaller fire this way, and still get all the heating and viewing satisfaction.