.... 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
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?
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
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.
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
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
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
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.
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
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.
... 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
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
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. … Continue reading And Now for Something Completely Different: Rotation Heat Pump!
October - time for updating documentation of the heat pump system again! Consolidated data are available in this PDF document. In the last season there were no special experiments - like last year's Ice Storage Challenge or using the wood stove. Winter was rather mild, so we needed only ~16.700kWh for space heating plus hot … Continue reading Same Procedure as Every Autumn: New Data for the Heat Pump System
The proof by contradiction used in physics textbooks is one of those arguments that appear surprising, then self-evident, then deceptive in its simplicity. You - or maybe only: I - cannot resist turning it over and over in your head again, viewing it from different angles. tl;dr: I just wanted to introduce the time-honored tradition … Continue reading Re-Visiting Carnot’s Theorem
In the last post, I showed how to use Raspberry Pi as CAN bus logger - using a test bus connected to control unit UVR1611. Now I have connected it to my heat pump's bus. Credits for software and instructions: juerg5524.ch messpunkt.org SK Pang Special thanks to SK Pang Electronics who provided me with CAN … Continue reading Hacking My Heat Pump – Part 2: Logging Energy Values
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
Three years ago I found a research paper that proposed a combination of distributed computing and heating as a service: A cloud provider company like Google or Amazon would install computers in users' homes - as black-boxes providing heat to the users and computing power to their cloud. In the meantime I have encountered announcements … Continue reading Everything as a Service
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
Over the holidays I stayed away from social media, read quantum physics textbooks instead, and The Chief Engineer and I mulled over the fundamental questions of life, the universe and everything. Such as: How to explain our heat pump system? An astute reader suggested to create an 'animation' of the gradual evolution of the system's … Continue reading How Does It Work? (The Heat Pump System, That Is)
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
We have updated the documentation of monthly and seasonal measurement data - now including also the full season September 2014 to August 2015. The overall Seasonal Performance Factor was 4,4 - despite the slightly lower numbers in February and March, when was the solar collector was off during the Ice Storage Challenge. Edit: I have … Continue reading Heat Pump System Data: Three Seasons 2012 – 2015
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!)
The straight-forward way is to read off two energy values at the end of a period - day, month, or season: The electrical energy used by the heat pump and the heating energy delivered. The Seasonal Performance Factor (SPF) is the ratio of these - the factor the input electrical energy is 'multiplied with' to … Continue reading How to Evaluate a Heat Pump’s Performance?
I have received several questions related to my article on data logging on this blog, or to my postings on monitoring and control on our German blog. Thus I have decided to write the article I would have wanted to read when I once made myself familiar with this. The target audience for this article are … Continue reading Data Logging with UVR1611 – FAQ
The more we enjoyed our spring-like winter, the more we were worried if we will ever see much ice in our underground water tank this heating season. So we did what I had announced - we switched off the solar collector completely: Since February 1st our heat pump has been extracting heat energy from the tank … Continue reading The Ice Storage Challenge
I have become obsessed with comparing climate data for different regions in the world and in different years (space + time). Finally I have found the tool I was looking for; now I can compare average Ice Days quickly - days with a maximum temperature < 0°C. In the first quarter of 2014 there were: 5 … Continue reading More Ice? Exploring Spacetime of Climate and Weather.
We all do risk management intuitively - when we decide on uploading our data to the cloud where the NSA may spy on us. Or when we install heating systems that depend on electrical energy. The previous post triggered an interesting discussion about the risk of a power outage. Is it more risky to pick … Continue reading Personal Risk Assessment