They Shall Shine in the Dark

On February 24 I wrote: They shall shine in the dark. I use this sentence as a seed for Twitter search poetry - interlacing poetry with temperature waves again . ~ ~~ ~~~ ~~~~ They shall shine in the dark The interstellar void going down much faster determined to take over under renewed attack under … Continue reading They Shall Shine in the Dark

Tribute to a Pragmatic Swiss Solar Pioneer – Who Called to Action in 1989

He is called a pragmatic doer, knowing his physics and engineering, devoid of ideology. This is how Josef Jenni is introduced in the preface to his document called How can we achieve the energy transition (Wie erreichen wir die Energiewende). It's a manifesto and a technical overview - by the pioneer whose company had built … Continue reading Tribute to a Pragmatic Swiss Solar Pioneer – Who Called to Action in 1989

Loops Near the surface. Lumped Together in Space.

There was a time, when most articles here looked like lab reports or chapters of a thesis. Occasionally, there was a weird poem thrown in. Now is the time for art only, and the thesis-like postings provide for raw material. Temperature waves beneath the ground, driven by the oscillation of the temperature on the surface … Continue reading Loops Near the surface. Lumped Together in Space.

Pioneers of the Oil Shock Era

.... a lot had been done right after the 1973 oil embargo but there exist almost no documents on theses activities. The concerned pioneers were realizing all types of heat pump systems, sometimes day and night. But they did not care for publishing. ... says Professor of Engineering Martin Zogg, in his research report History … Continue reading Pioneers of the Oil Shock Era

Innovation and Scarcity (and Panic)

I tried to avoid such words. They sounded like hollow buzzwords in times of abundance, used by advertizers playing on fears. But our complacent world is taught a lesson, right now, at furious speed. I am following news as everybody else, I am reading about gloomy forecasts. An Austria paper mill has announced today it … Continue reading Innovation and Scarcity (and Panic)


When you move from fundamental principles (in physics)  to calculating something 'useful' (in engineering), you seem to move from energy to enthalpy. Enthalpy is measured in Joule, as well as energy. It is assigned to a 'system', a part of the physical world separated from other parts by interfaces. The canonical example is a vessel … Continue reading Enthalpy

The Solar Self-Building Movement

Every year the International Energy Agency publishes a detailed report on worldwide usage of solar thermal energy. The last one from 2019 is based on data from 2017. Countries are ranked by their installed capacity: Collectors' thermal heating power under standard operating conditions is linked to their area: 0.7 kWth (kilo Watt thermal) per square … Continue reading The Solar Self-Building Movement

A Color Box. Lost in Translation

It was that time again. The Chief Engineer had rebuilt the technical room from scratch. Each piece of heavy equipment had a new place, each pipe and wire was reborn in a new incarnation (German stories here.) The control system was turned upset down as well, and thus the Data Kraken was looking at its … Continue reading A Color Box. Lost in Translation

Infinite Loop: Theory and Practice Revisited.

I've unlocked a new achievement as a blogger, or a new milestone as a life-form. As a dinosaur telling the same old stories over and over again. I started drafting a blog post, as I always do since a while: I do it in my mind only, twist and turn in for days or weeks … Continue reading Infinite Loop: Theory and Practice Revisited.

Where Are the Files? [Winsol – UVR16x2]

Recently somebody has asked me where the log files are stored. This question is more interesting then it seems. We are using the freely programmable controller UVR16x2 (and its predecessor) UVR1611) ... .. and their Control and Monitoring Interface - CMI: The CMI is a data logger and runs a web server. It logs data … Continue reading Where Are the Files? [Winsol – UVR16x2]

Logging Fun with UVR16x2: Photovoltaic Generator – Modbus – CAN Bus

The Data Kraken wants to grow new tentacles. I am playing with the CMI - Control and Monitoring Interface - the logger / 'ethernet gateway' connected to our control units (UVR1611, UVR16x2) via CAN bus. The CMI has become a little Data Kraken itself: Inputs and outputs can be created for CAN bus and Modbus, … Continue reading Logging Fun with UVR16x2: Photovoltaic Generator – Modbus – CAN Bus

Can the Efficiency Be Greater Than One?

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 … Continue reading Can the Efficiency Be Greater Than One?

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 … Continue reading Consequences of the Second Law of Thermodynamics

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! … Continue reading The Heat Source Paradox

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 … Continue reading Things You Find in Your Hydraulic Schematic

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 … Continue reading Cooling Potential

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 further.

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 … Continue reading Data for the Heat Pump System: Heating Season 2016-2017

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 … Continue reading Tinkering, Science, and (Not) Sharing It

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 … Continue reading Simulations: Levels of Consciousness

Heat Transport: What I Wrote So Far.

Don't worry, The Subversive Elkement will publish the usual silly summer posting soon! Now am just tying up loose ends. In the next months I will keep writing about heat transport: Detailed simulations versus maverick's rules of thumb, numerical solutions versus insights from the few things you can solve analytically, and applications to our heat … Continue reading Heat Transport: What I Wrote So Far.

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 … Continue reading Simulating Peak Ice

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 … Continue reading Mr. Bubble Was Confused. A Cliffhanger.

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 … Continue reading Where to Find What?

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, … Continue reading Ice Storage Hierarchy of Needs

Earth, Air, Water, and Ice.

In my attempts at Ice Storage Heat Source popularization I have been facing one big challenge: How can you - succinctly, using pictures - answer questions like: How much energy does the collector harvest? or What's the contribution of ground? or Why do you need a collector if the monthly performance factor just drops a … Continue reading Earth, Air, Water, and Ice.

Frozen Herbs and Latent Energy Storage

... having studied one subject, we immediately have a great deal of direct and precise knowledge ... of another. --Richard Feynman Feynman referred to different phenomena that can be described by equations of the same appearance: Learning how to calculate the distribution of electrical charges gives you the skills to simulate also the flow of … Continue reading Frozen Herbs and Latent Energy Storage

On Photovoltaic Generators and Scattering Cross Sections

Subtitle: Dimensional Analysis again. Our photovoltaic generator has about 5 kW rated 'peak' power - 18 panels with 265W each. Peak output power is obtained under so-called standard testing condition - 1 kWp (kilo Watt peak) is equivalent to: a panel temperature of 25°C (as efficiency depends on temperature) an incident angle of sunlight relative to … Continue reading On Photovoltaic Generators and Scattering Cross Sections

My Data Kraken – a Shapeshifter

I wonder if Data Kraken is only used by German speakers who translate our hackneyed Datenkrake - is it a word like eigenvector? Anyway, I need this animal metaphor, despite this post is not about facebook or Google. It's about my personal Data Kraken - which is a true shapeshifter like all octopuses are. (Because … Continue reading My Data Kraken – a Shapeshifter