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
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.
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
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?
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
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
After I presented details for selected days, I am going to review overall performance in the first year. From June 2015 to May 2016 ... … we needed 6.600 kWh of electrical energy in total. The heat pump consumed about 3.600 kWh of that ... … in order to 'pump it up to' 16.800 kWh … Continue reading First Year of Rooftop Solar Power and Heat Pump: Re-Visiting Economics
You can generate electrical power at home but you cannot manufacture your own natural gas, oil, or wood. (I exempt the minority of people owning forestry). This is often an argument for the combination of heat pump and photovoltaic generator. Last year I blogged in detail about economics of solar power and batteries and on … Continue reading Photovoltaic Generator and Heat Pump: Daily Power Generation and Consumption
I am sure it protects us not only from lightning but also from alien attacks and EMP guns ... So I wrote about our lightning protection, installed together with our photovoltaic generator. Now our PV generator is operational for 11 months and we have encountered one alien attack, albeit by beneficial aliens. The Sunny Baseline … Continue reading Alien Energy
Nearly all of renewable energy exploited today is, in a sense, solar energy. Photovoltaic cells convert solar radiation into electricity, solar thermal collectors heat hot water. Plants need solar power for photosynthesis, for 'creating biomass'. The motion of water and air is influenced by the forces caused by the earth's rotation, but by temperature gradients … Continue reading Temperature Waves and Geothermal Energy
Our PV generator and new metering setup is now operational for half a year; this is my next wall of figures. For the first time I am combining data from all our loggers (PV inverter, smart meter for consumption, and heat pump system's monitoring), and I give a summary on our scrutinizing the building's electrical … Continue reading Half a Year of Solar Power and Smart Metering
In the previous post I gave an overview of our recently compiled data for the heat pump system. The figure below, showing the seasonal performance factor and daily energy balances, gave rise to an interesting question: In February the solar collector was off for research purposes, and the performance factor was just a bit lower … Continue reading Economics of the Solar Air Collector
July 2015 was the hottest July ever since meteorological data had been recorded in Austria (since 248 years). We had more than 38°C ambient air temperature at some days; so finally a chance to stress-test our heat pump system's cooling option. Heating versus cooling mode In space heating 'winter' mode, the heat pump extracts heat … Continue reading Having Survived the Hottest July Ever (Thanks, Natural Cooling!)
This is the third post in my series on our photovoltaic generator. It had been a part of previous post with the data for the first month, but I cut and saved it as the other post was so long already. I am now also able to present data for two months of operations: Below … Continue reading Solar Energy, Batteries, and Autonomy
On May 4, 2015, we started up our photovoltaic generator. Here are some numbers and plots for the first month - and what I plan to do next. Our generator has a rated power of 4,77 kWp (kilowatt peak), one module has 265 Wp. The generator would deliver 4,77 kW of electrical power under so-called … Continue reading Solar Power: Some Data for the First Month.
After a little delay our photovoltaic generator went online - we had been waiting for the delivery of this sophisticated addition to our office decoration: People on G+ had very cool suggestions, such as a rotating alien-fighting device throwing darts. Closest to the truth were: fuse box and fire alarm. The box containing two knobs … Continue reading Two Weeks After Lift-Off
We had considered it already a few years ago - when we decided to live and work in the middle of a dusty and noisy construction site for a few months: The upper part of the roof is inclined by 30° - which is the optimum angle for photovoltaic panels - whereas the windows in … Continue reading We Have Come a Long Way: Rooftop Solar Power Now!
And we will not be able to contribute - by a hair. We have just ordered our photovoltaic generator, and installation is planned for April. It is the (partial) Solar Eclipse on March 20 that made Europe's Transmission System Operators (TSOs) release an announcement: Under a clear morning sky on 20 March 2015, some 35000 … Continue reading “An Unprecedented Test for Europe’s Electricity System”
One of the most recent search terms on this blog was: 'cistern for water source heat pump'. I wanted to double-check and searched for this phrase myself. This was the first Google Search result: Cistern-Based Water-Source Heat Pump System Design ... a research paper that had been available for download at the website of Iowa … Continue reading Cistern-Based Heat Pump – Research Done in 1993
After the musings on Life, the Universe and Everything you deserve a break - and a post with not too much verbiage. I am borrowing some images from a series of posts the Chief Engineer is currently running on our German blog. (My job title is Science Officer, but we don't have a Captain). This … Continue reading Art from Plastic and Wood
In this post I try something new: I will keep it short. This is actually an update long overdue. Months ago I have written a post on how to control the four elements that is how to harvest energy from ambient air, solar radiation, the freezing of water, and ground here. A loyal reader told … Continue reading Lost in Translation – an Overdue Update
Despite my attempts to post mainly geeky and weird stuff peppered with (very often not down-to-earth) physics, I got involved in some serious discussions on renewable energy, sustainability, heat pumps, and the pleasures of Building Your Own Stuff. So I will describe what I am actually working on / playing with when I am not … Continue reading Controlling the Four Elements. Or: Why Heat Pumps Are Cool.