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

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.

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

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

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

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.

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

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!

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