The research showed that these panels will work in northern climates. The system was operated over a one month period in February and March when temperatures were at times lower than -20º C.

Solar Heating in Saskatchewan in the Winter

Bill Elliott | WSE Technologies

08/01/07, 12:00 AM | Solar Power | Projects and Tours
Solar Heating in Saskatchewan in
The research showed that these panels will work in northern climates. The system was operated over a one month period in February and March when temperatures were at times lower than -20º C.
Solar Heating in Saskatchewan in the Winter
Bill Elliott
WSE Technologies

Well its forty below and we don't give a #@%### , if you are from Western Canada you will know the song.

But amazing as it seems the sun has lots of potential energy ... just not a lot of hours of sunshine..

For you engineering types

Project Objectives

This project set out to determine if the panels could produce heat in cold climates and if so, how much? The project also attempted to develop a heating system for a building that could be totally solar powered and be independent of grid power.

The technical uncertainties were as follows:

  • Will the panel produce any net heat in a climate where the temperature can drop to -40º C
  • Which operating fluid is most suitable to use in sub-zero temperatures
  • Will the panel act in a negative fashion to refrigerate on clear nights
  • Can a system be devised that would not require any connection to a power grid

Background work completed

Initial research was conducted to estimate how much heat might be expected by determining the total amount of solar radiation being received at our latitude and time of year. By estimating the projected area of the solar panel tubes it was determined that the total energy striking the panel would be about 2600 btu/hr. If we assume an efficiency of 80%, we should get about 2000 btu/hr out of the system. The other necessary components would be designed around these assumptions.

The operating fluid must be able to tolerate sub-zero temperatures without freezing. Windshield washer fluid, RV antifreeze and ethylene glycol are possible candidates. However since RV antifreeze and windshield washer fluids contain ethanol which presents a fire hazard, ethylene glycol was chosen in spite of its relatively high cost.

To provide for the requirement that the system be capable of operating off grid, a 12 volt pump and a 12 volt fan coil unit were powered by a 12 volt battery supplied by a photovoltaic cell

The system was set up with the panel facing due south and tilted at an angle of 45 degrees.

Note the snow and ice on the above picture. At the time of this photo, the outdoor temperature was -15º C and the fluid supply temperature was 40º C.

The fluid was pumped indoors to the fan coil unit.

Technical Problems Resolved

The research showed that these panels will work in northern climates. The system was operated over a one month period in February and March when temperatures were at times lower than -20º C. This graph shows typical results from March 21, 2007.


Solar heat as a function of time.

A number of conclusions can be reached from this research:

  • The panel will produce heat in cold climates
  • The heat output is fairly independent of the solar angle during the day
  • The heat output is fairly independent of ambient temperature
  • Using a 12 volt automotive battery and solar panel this system can operate in remote areas where no power is available.
  • While the fluid in the panel can cool below ambient temperature at night due to radiation into outer space, it does not pose a problem since the cold high density fluid simply stays in the tubes until re-heated after sunrise.
  • The panel captures at least 80% of the total solar energy
 
The content & opinions in this article are the author’s and do not necessarily represent the views of AltEnergyMag
08/01/07, 12:00 AM | Solar Power | Projects and Tours
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