Solar Retrofit Part 10 – Monitoring (continued)

My house uses natural gas for space heat and domestic hot water. When analyzing the benefit of my solar collectors, the obvious thing to do is to examine the actual change in my gas consumption. To answer this, I've plotted the amount of gas I burned per heating degree day (HDD) per month. Using HDDs adjusts for the variability of the weather and allows an apples-to-apples comparison between different years.

 read more... »

Solar Retrofit Part 9: Monitoring

I thought I'd share some graphs showing the output of my solar collectors and the results of my recent renovations (collector installation included) on my home energy use.  Here is the heat collected (measured in kwh) plotted with the maximum daytime temperature:  read more... »

Solar Retrofit Part 8: Winter performance

Today (Saturday November 20th) was the first sunny day in a while.  While cleaning up the breakfast dishes I was not surprised to hear the solar pump start.  When I checked I found that my solar tank was down to 20 degrees C, the solar collectors were at 29 degrees C and the outside temperature was minus 17 degrees C.  What did surprise me was that when I left the house to run some errands (around 10:40 AM) I found the collectors were still partially covered in snow! 

Snow covered collectors: Partially obscured flat plate collectors

Snow covered collectors

This mean that my collectors managed to get a 45 degree C differential to the ambient temperature even while partially obscured.  How great is that?

Solar Retrofit Part 7: Installation

It's been a long road but my system is now up and running! I expect that a lot of people will ask how much energy my installation actually collects so I ended up taking the $600 Government of Canada Eco-Energy rebate for my high-efficiency boiler and bought a BTU meter ( from the guys at WSE Technologies ( So far the BTU meter is up to 84kwh which means I've collected (84 kwh * 3400 BTU/kwh =) 285,600 BTUs of heat. The temperature sensor at the _bottom_ of my storage tank didn't drop below 58 degrees C all week so I'm pretty sure that my boiler hasn't run since I completed the installation.

There are a few outstanding things I have to take care of: Insulation and cladding on a portion of the exterior runs and insulation on the piping in the house. Also, I've talked to IBC boilers and they don't yet have a controller module that integrates the boiler and the solar so I'll try and rig something up so that I can use the collectors to help heat my home. At 9:40 this morning (August 28, 2010) the outside temperature was 12 degrees C and I was suprised to hear the collector pump start. Despite the fact there was light cloud cover, the temperature sensor in the collectors was reading 68 degrees C.

Here are some pictures:

 read more... »