And Now for Something Completely Different: Rotation Heat Pump!

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!

Same Procedure as Every Autumn: New Data for the Heat Pump System

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

Re-Visiting Carnot’s Theorem

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

Hacking My Heat Pump – Part 2: Logging Energy Values

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

Hacking My Heat Pump – Part 1: CAN Bus Testing with UVR1611

In the old times, measuring data manually sometimes meant braving the elements: Now, nearly all measurements are automated: In order to calculate the seasonal performance factor of the heat pump system we have still used the 'official' energy reading provided by the heat pump's display. Can't this be automated, too? Our Stiebel-Eltron WPF7 basic is … Continue reading Hacking My Heat Pump – Part 1: CAN Bus Testing with UVR1611

First Year of Rooftop Solar Power and Heat Pump: Re-Visiting Economics

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

Photovoltaic Generator and Heat Pump: Daily Power Generation and Consumption

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

Everything as a Service

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

Alien Energy

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

Rowboats, Laser Pulses, and Heat Energy (Boring Title: Dimensional Analysis)

Dimensional analysis means to understand the essentials of a phenomenon in physics and to calculate characteristic numbers - without solving the underlying, often complex, differential equation. The theory of fluid dynamics is full of interesting dimensionless numbers -  Reynolds Number is perhaps most famous. In the previous post on temperature waves I solved the Heat … Continue reading Rowboats, Laser Pulses, and Heat Energy (Boring Title: Dimensional Analysis)

No, You Cannot ‘Power Your Home’ by One Hour of Cycling Daily

In the past days different versions of an article had popped up in my social media streams again and again - claiming that you could power your home for 24 hours by cycling for one hour. Regular readers know that I craft my statements carefully in articles about energy, nearly as in the old times … Continue reading No, You Cannot ‘Power Your Home’ by One Hour of Cycling Daily

Temperature Waves and Geothermal 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

How Does It Work? (The Heat Pump System, That Is)

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)

Half a Year of Solar Power and Smart Metering

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

Peter von Rittinger’s Steam Pump (AKA: The First Heat Pump)

Peter von Rittinger's biography reads like a Victorian novel, and his invention was a text-book example of innovation triggered by scarcity. Born 1811, he was poor and became an orphan early. Yet he was able to study mathematics and physics as his secondary education had been financed by the Piarist Order. He also studied law … Continue reading Peter von Rittinger’s Steam Pump (AKA: The First Heat Pump)

The Impact of Ambient Temperature on the Output Power of Solar Panels

I have noticed the impact of traversing clouds on solar power output: Immediately after a cloud has passed, power surges to a record value. This can be attributed to the focusing effect of the surrounding clouds and/or cooling of the panels. Comparing data for cloudless days in May and June, I noticed a degradation of … Continue reading The Impact of Ambient Temperature on the Output Power of Solar Panels

Economics of the Solar Air Collector

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

Heat Pump System Data: Three Seasons 2012 – 2015

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

Having Survived the Hottest July Ever (Thanks, Natural Cooling!)

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!)

Solar Energy, Batteries, and Autonomy

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

Solar Power: Some Data for the First Month.

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.

An Efficiency Greater Than 1?

No, my next project is not building a Perpetuum Mobile. Sometimes I mull upon definitions of performance indicators. It seems straight-forward that the efficiency of a wood log or oil burner is smaller than 1 - if combustion is not perfect you will never be able to turn the caloric value into heat, due to … Continue reading An Efficiency Greater Than 1?

Two Weeks After Lift-Off

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

Watching TV Is Dangerous

I am not talking about humans. But TV-sets might threaten other devices in the smart home; this was a recent puzzle submitted by a blog reader. Two unrelated devices / services met on the user's local computer network: IP-TV provided by a large German telco. a data logger for monitoring the heating system. This user … Continue reading Watching TV Is Dangerous

How to Evaluate a Heat Pump’s Performance?

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?

Ice Storage Challenge: High Score!

Released from ice are brook and river By the quickening glance of the gracious Spring; The colors of hope to the valley cling, And weak old Winter himself must shiver, Withdrawn to the mountains, a crownless king. These are the first lines of the English version of a famous German poem on spring, from the … Continue reading Ice Storage Challenge: High Score!

We Have Come a Long Way: Rooftop Solar Power Now!

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!

Data Logging with UVR1611 – FAQ

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 Ice Storage Challenge

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

“An Unprecedented Test for Europe’s Electricity System”

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”