Category: punktwissen

Consequences of the Second Law of Thermodynamics

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…
The Heat Source Paradox

It is not a paradox – it is a straight-forward relation between a heat pump system’s key data: The lower a heat pump’s performance factor is, the smaller the source can be built. I would not write this post, hadn’t I found a version of this statement with a positive twist used in an advert!…
Things You Find in Your Hydraulic Schematic

Building an ice storage powered heat pump system is a DIY adventure – for a Leonardo da Vinci of plumbing, electrical engineering, carpentry, masonry, and computer technology. But that holistic approach is already demonstrated clearly in our hydraulic schematics. Actually, here it is even more daring and bold: There is Plutonium – Pu – everywhere…
Cooling Potential

I had an interesting discussion about the cooling potential of our heat pump system – in a climate warmer than ours. Recently I’ve shown data for the past heating season, including also passive cooling performance: After the heating season, tank temperature is limited to 10°C as long as possible – the collector is bypassed in…
Reverse Engineering Fun

Recently I read a lot about reverse engineering – in relation to malware research. I for one simply wanted to get ancient and hardly documented HVAC engineering software to work. The software in question should have shown a photo of the front panel of a device – knobs and displays – augmented with current system’s…
Simulating Life-Forms (2): Cooling Energy

I found an incredibly detailed research report by the Australian government – about energy use in private homes, by appliance and purpose. It confirms my reluctance to ‘predict’ cooling energy as usage of air conditioning depends strongly on life-style choices.
Entropy and Dimensions (Following Landau and Lifshitz)

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…
The Collector Size Paradox

Collector harvest does not change much if we only use half the collector. Perhaps counter-intuitive but explained by the characteristics of heat exchangers connected in series: Especially if one of the heat exchangers (in the tank or collector) is already much superior to the other one, it does not help to optimize the good one…
The Orphaned Internet Domain Risk

I have clicked on company websites of social media acquaintances, and something is not right: Slight errors in formatting, encoding errors for special German characters. Then I notice that some of the pages contain links to other websites that advertize products in a spammy way. However, the links to the spammy sites are embedded in…
Data for the Heat Pump System: Heating Season 2016-2017

I update the documentation of measurement data [PDF] about twice a year. This post is to provide a quick overview for the past season. The PDF also contains the technical configuration and sizing data. Based on typical questions from an ‘international audience’ I add a summary here plus some ‘cultural’ context: Building: The house is…
Tinkering, Science, and (Not) Sharing It

I stumbled upon this research paper called PVC polyhedra: We describe how to construct a dodecahedron, tetrahedron, cube, and octahedron out of pvc pipes using standard fittings. … In particular, if we take a connector that takes three pipes each at 120 degree angles from the others (this is called a “true wye”) and we…
Simulations: Levels of Consciousness

In a recent post I showed these results of simulations for our heat pump system: I focused on the technical details – this post will be more philosophical. What is a ‘simulation’ – opposed to simplified calculations of monthly or yearly average temperatures or energies? The latter are provided by tools used by governmental agencies…
Bing Says We Are Weird. I Prove It. Using Search Term Poetry.

Bing has done so repeatedly: In order to learn more about this fundamental confusion I investigated my Bing search terms. [This blog has now entered the phase of traditionally light summer entertainment.] Rules: _______________________ you never know my life and my work is life just about working please try to give a substantial answer element…
You Never Know

… when obscure knowledge comes in handy! You can dismantle an old gutter without efforts, and without any special tools: Just by gently setting it into twisted motion, effectively applying ~1Hz torsion waves that would lead to fatigue break within a few minutes. I knew my stint in steel research in the 1990s would finally…
Simulating Peak Ice

This year ice in the tank was finally melted between March 5 to March 10 – as ‘visual inspection’ showed. Level sensor Mr. Bubble was confused during the melting phase; thus it was an interesting exercise to compare simulations to measurements. Simulations use the measured ambient temperature and solar radiation as an input, data points…
Mr. Bubble Was Confused. A Cliffhanger.

This year we experienced a record-breaking January in Austria – the coldest since 30 years. Our heat pump system produced 14m3 of ice in the underground tank. The volume of ice is measured by Mr. Bubble, the winner of The Ultimate Level Sensor Casting Show run by the Chief Engineer last year: The classic, analog…
Where to Find What?

I have confessed on this blog that I have Mr. Monk DVDs for a reason. We like to categorize, tag, painstakingly re-organize, and re-use. This is reflected in our Innovations in Agriculture … … as well as in my periodical Raking The Virtual Zen Garden: Updating collections of web resources, especially those related to the…
Ice Storage Hierarchy of Needs

Data Kraken – the tentacled tangled pieces of software for data analysis – has a secret theoretical sibling, an older one: Before we built our heat source from a cellar, I developed numerical simulations of the future heat pump system. Today this simulation tool comprises e.g. a model of our control system, real-live weather data,…