The microwave oven is one of the most wondrous things ever devised. Take your leftovers out of the fridge, push a button, and two minutes later you're eating, in front of the TV.
My cabin doesn't have suitable power to operate one of those. So, I'm coming up with a workaround. I envision a very well-insulated oven, that is allowed to get super hot, say 600 Degrees or so. Heavy fire brick on the inside, so that it stays hot, hours after the fire goes out. Inside the oven, I would store cast iron skillets, blue schist stones and other heavy items that have a lot of thermal mass and can be used to cook food.
The idea, is to be able to grab something hot from the oven and quickly spread food along the hot surface, so that food can be heated up, without the need to start a fire.
I'm now going to stop writing this and conduct a simple test. I'm heating a small cast pan, to 400 degrees. It's a high-quality older one that is fairly thin. I imagine some of the big lumps of cast, like Lodge, would be even better at this, since they are heavy. I'm also heating a dinner plate, as a lid. It's a pretty regular one. I imagine using a heavy piece of stoneware, for greater thermal mass.
Fiddling, fiddling, fiddling, and I'm back.
I heated my small, cast pan and a relatively small dinner plate, to 400 degrees. I keep the fridge two degrees above freezing. Beef stew and potatoes were removed from the fridge and quickly spread along the pan, with more of it going onto the outer edge, since there is quite a bit of cast that rises above the food zone. I put the hot plate on top and then quickly covered everything with 2 kitchen towels and the shirt I was wearing. So, the thin layer of food had a 400-degree pan beneath, and a 400-degree lid. The pan was set on a wooden cutting board. Time to build the hay box.
After two minutes, the insulation was removed and the food stirred a bit, to make sure that all came in contact with the hot metal. This brought the meal to a nice comfortable temperature for eating. I ate right out of the pan, and left the plate wrapped in a towel. It was still pretty hot to the touch, when I finished. If the phone had rang, I would have put the lid back on and covered it with the towel again, to keep the meal warm. I'm all done now and the frying pan is cool enough to pick up, but certainly not cold. I'm claiming success.
Total time between placing food in the hot pan and starting to eat, was 3 minutes. I can live with that. That is similar to what happens with microwaves, without the hotspots. It was all heated pretty evenly.
Next, was a minor experiment with heating up a drink. This molasses and cocoa drink, was in the fridge. When poured into this small pan, and allowed to sit for 1 minute, it was somewhat too hot. I poured it back into the cold cup, and 30 seconds later, it was just right.
It would have been nice to test it with grilled cheese or some other item that does well with radiant heat. Cold oatmeal is what I had on hand.
Frying pans were both heated. I'm not sure how hot, but residue on the bottom of one of them started to smoke. I used a thin Corelle plate, to suspend the porridge on the upper rim of the smaller pan. Then the larger pan was placed over top, and everything covered with two kitchen towels. I did this right on the glass top of the stove, being careful to leave a gap, around the area right above the element. Didn't want to get a fire going. This has effectively created a little oven.
After 10 minutes, the porridge was warm, but not hot. There was plenty of stored heat in just the big frying pan, to get this much porridge bubbling. So, when radiant heat is wanted, such as when a fajita is being reheated, it's probably best to just place it in the already hot, brick oven.
Wow, Dale! This is a great idea, and an excellent way to make it easy to reheat food without a ton of hassle! The pictures make it easy to follow as well.
For folks living mostly on wood heat, this would be very easy of course. If a conventional wood stove, just stick your pan in the firebox when you're letting it die down. If an RMH, leave a little box in the mass and make a well-insulated door to close it off. Store a few pans/skillets in the box, let them warm up at the start of the day with the mass (maybe put them close to the exhaust pipe/heat riser to make sure they get nice and warm) then take them out like you did when you need to heat something up!
Lia gets it. The whole idea is to use the stored heat from an earlier fire, so that a fire doesn't need to be lit every time.
My experiments with blue schist Rock, we're quite successful. It took 3 minutes to make a perfect grilled cheese, when it was placed between two rocks that had been in the oven. An oven directly above the heat riser, could easily start off at six or seven hundred degrees. If given a thick layer of insulation, stuff could stay hot for many hours.
Suppose you have an oven like this, and the house is getting just a little cold, the door could be opened, so that the mass quickly loses heat. Get your fire going, and leave the oven open, until the house is just about warm enough again, then close it, so that more is being stored, and less is being immediately radiated into the room.
I have often thought that when I design and build an RMH for myself, I want to have something like your hay box idea incorporated into the design. I was thinking pizza oven (mmmmm...pizza... *drools*) where my other half could also bake breads and pies (mmmmm...pies...plural... *drools*), and I think this is a compatible idea.
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein
The horizontal bottom of the J tube, is the perfect spot for a pizza oven. Mine is made from dense firebrick that is good for absorbing and transferring heat. A sheet of thick steel, could rest on top of the bricks, to form a base, and to conduct heat toward the furthest edges, for even heating. It would need to be completely supported from beneath, by cob and firebrick. If made 8 inches high, it could accommodate a dutch oven size pot.
Pizza would rest on one of those ceramic trays. When you want to fry eggs or a steak, the pan could be placed right on the steel base, for quick heat transfer. Close the door for a couple minutes and you're cooking from top and bottom.
The top of a Thermal Mass, Rocket Fired Pizza Oven, would be quite hot. A perfect place to build a cob dome oven with some oven racks, salvaged from an old stove, set to hold plates, cups for hot drinks, and frying pans. This would be heated just by the heat leaving the top of the pizza oven. When nice thick stoneware plates are preheated, dinner doesn't get cold after 30 seconds. This would also make a great warming oven, when you aren't trying to zap things at microwave speed. If it's time for dinner and the plates are too hot, fling the doors open and heat the room. The warming oven could also be a good place to keep a pot of water, provided it's not allowed to get above boiling temperature. But, say it's sitting at 180. Transfer the pot to the lower oven, and you're making coffee 2 minutes later. That's what a microwave does.
It was really f---ing cold, during the three-day period when I build my stove. I got about one third of the way through and then decided the only way my hands were going to touch that clay again, was if it was warm. So I fired the thing, and kept it firing during the entire building process. I kept a 4-gallon pot of water, right on that portion of the j tube where I'm suggesting the pizza oven. It stayed nice and hot.
Companion Planting Guide by World Permaculture Association