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