Once we have large burners and monotube steam generators we can turn heat into another hot gas, which is steam, that contains a lot more heat that hot air. We need heat more than we need temperature because we need to fumigate the top foot of soil in order to grow plants. The problem is verticillium wilt, fusarium wilt, and macrophomina, as well as root knot nematodes, more commonly referred to as Meloidogyne. Fumigation also kills weed seeds. The problem is two-fold: political and chemical. The political problem is that methyl bromide is outlawed by a bunch of do-gooders who do not realize that four times as much bromide is put into the atmosphere by ocean waves as is put there by farmers using methyl bromide. Therefore agricultural usage is de minimus as far as ozone layers are concerned.
It is possible to fumigate soil with heat and the problem here is chemical because when organic matter is heated above 180 degrees F it changes into some compound that is not good. I took history in college and do not know what that compound is. If anyone can figure out how to inject high temperature and high pressure steam into the ground that will heat up all of the soil particles uniformly and for however many minutes is required to do the job we can make the world a better place. Some may ask about using hot water to do the job and this will work although the amount of water needed to soak a foot of soil and heat it up is huge, maybe several hundred times as much water that would be needed if it were turned into steam.
I see a machine that pulls hollow tines through the soil injecting high pressure steam a foot or so down. The tines are covered by a large box made of quarter inch diamond plate steel that skids along on top of the ground sealing in the steam so that when the high pressure steam gets going and large clumps of dirt and rocks are flying all over the place they will bounce off the metal box and not do any more damage. All of that kinetic energy will obviate the need for mechanical tillage, which usually is needed in the form of a rototiller or a spader. If someone can figure out how to not ruin the soil chemistry with the high heat we are in business. I will make money. The Ozone will be saved. Farmers will be able to grow strawberries again. And we will then be one small step away from steam powered tractors.