This thing has moved to Youmagine: https://www.youmagine.com/designs/efficient-open-fireplace This is a design for an efficient open fireplace. It's based on classic British Victorian fitting into a brick chimney. This design is roughly based on a real Victorian cast-iron design, except that it has a number of enhancements and features. These are: All open fires are inherently inefficient (in terms of the energy of the fuel and the energy transferred to the room). The up-draft of heat up the chimney also tends to "suck" the air (and heat) out of the room and wastes it up the chimney. However, this open-fire design aims to increase the amount of "usable" heat from the burning fuel. It's probably not as good as a wood burning stove, but hopefully a lot better than an original Victorian fireplace.Just about all of the sizes, scales and tolerances are very forgiving. The Sketchup source file is included to make derivatives. The object is around 100mm square, so obviously needs scaling to make a model or for using as a building template.