Friday, November 06, 2015

compost temperature

Knowing the temperature deep in my compost pile gives me an idea of how well decomposition is going. This is a fresh pile about a week old made mostly of moist chopped up leaves (mostly maple) along with some other plant materials roughly mixed in.

The outside temperature is in the low 13C/55F. As shown by a thermocouple 24 inches into the pile, roughly in the center, temperature is almost 127F!

I will come back to the pile throughout the next few weeks to record the internal temperature. I won't leave the expensive thermocouple and meter outside. I will bring the two out when I want to check, inserting the thermocouple like a probe into two hollow tubes I have embedded in the pile.

I wonder about the amount of heat produced by the pile and how long it lasts? Would it be possible to extract from the pile to, for example, heat the shed nearby?

click pic to enlarge The pile is about 1 meter wide at the base, two meters in length and about 24"/60cm high about a week after being initially piled up.

The height of the pile is about 10cm lower now than a week ago. I expect that the pile will continue to fall as decomposition proceeds but less quickly. The pile will also be packed by the snow cover. The snow cover will act to insulate the pile. I don't plan to turn the pile until Spring.

I am using plastic electrical conduit for tunnels into the core of the compost pipe. I have measured off from the end with the distance (in inches) to the end of the pipe. There is a wooden plug hot glued into the inner pile ends.

The tubes were difficult to push to the desired depths. The cut up leaves had already compacted enough to make for heavy pushing. I will insert corks into the outer ends to keep the water and bugs out of the tubes when they don't have a thermocouple in the and will also avoid some heat loss.

Thanks for your interest. George Plhak, Lion's Head


Sunday, August 23, 2015

pool heating 2

Hello George,

I just stumbled across your blog on solar heating water using parabolic concentration. I am interested in heating my pool this way. The pool contains about 15,000 gallons of water and is 16 feet wide and 32 feet long and about 4 feet deep. How many of the of the units would I need to build in order to heat the pool in the summer months. The pool normally without heat would sit in the low to mid 70s and I would like to keep in in the mid 80s most of the time. I live in the pacific northwest near Bremerton, Washington.

Very Respectfully,


Hello Robert and thank you for writing.

Here are a few articles that may help:

My original book on the solar pool heater is still available as a download for only $10!

Thanks for your interest.

Saturday, May 30, 2015

reader projects 3

Occasionally I hear from readers who have built the unique parabolic solar heater in my book. Here are two recent examples for your inspiration.

The first is in Iran, built by Ehsan Saifali at the Isfahan Science and Technology Town (web address). He writes that the "purpose of our unit is a research work on solar hot water and desalination and thermal and concentrating photovoltaic".

The second is in Argentina, built by Pablo Peshiutta. Pablo has done an excellent job adapting the design for local materials. He could not locate the turntable bearings, so used roller bearings and a clever arrangement to rotate the reflectors.

You can see previous reader projects here and here.

I am very interested in hearing from you if you have built one of these systems and used my book for inspiration.

You can see background on my project here and you can buy my book at Your purchase of my book helps support my work.

Thank you for your interest,

George Plhak
Lion's Head, Ontario, Canada