I am dumping some equations here I need now and then! The sections about 3-dimensional temperature waves summarize what is described at length in the second part of this post. Temperature waves are interesting for simulating yearly and daily oscillations in the temperature below the surface of the earth or near wall/floor of our ice/water […]Read More Heat Conduction Cheat Sheet
This is one of the perennial top search terms for this blog. Anticlimactic answer: Yes, because input and output are determined also by economics, not only by physics. Often readers search for the efficiency of a refrigerator. Its efficiency, the ratio of output and input energies, is greater than 1 because the ambient energy is […]Read More Can the Efficiency Be Greater Than One?
Why a Carnot process using a Van der Waals gas – or other fluid with uncommon equation of state – also runs at Carnot’s efficiency. Textbooks often refer to an ideal gas when introducing Carnot’s cycle – it’s easy to calculate heat energies and work in this case. Perhaps this might imply that not only must the […]Read More Consequences of the Second Law of Thermodynamics
I found this comprehensive research report: Energy Use in the Australian Residential Sector 1986–2020 (June 2008) (several PDFs for download, click the link Energy Use… to display them) There are many interesting results – and the level of detail is impressive: The authors modelled the energy used per appliance type, by e.g. factoring in how […]Read More Simulating Life-Forms (2): Cooling Energy
Some time ago I wrote about volumes of spheres in multi-dimensional phase space – as needed in integrals in statistical mechanics. The post was primarily about the curious fact that the ‘bulk of the volume’ of such spheres is contained in a thin shell beneath their hyperspherical surfaces. The trick to calculate something reasonable is […]Read More Entropy and Dimensions (Following Landau and Lifshitz)
I don’t venture into speculative science writing – this is just about classical statistical mechanics; actually about a special mathematical aspect. It was one of the things I found particularly intriguing in my first encounters with statistical mechanics and thermodynamics a long time ago – a curious feature of volumes. I was mulling upon how […]Read More Spheres in a Space with Trillions of Dimensions
Heat pumps for space heating are all very similar: Refrigerant evaporates, pressure is increased by a scroll compressor, refrigerant condenses, pressure is reduced in an expansion value. *yawn* The question is: Can a compression heat pump be built in a completely different way? Austrian start-up ECOP did it: They invented the so-called Rotation Heat Pump. […]Read More And Now for Something Completely Different: Rotation Heat Pump!