Monday, February 11, 2013

Energy level model Feb'13

11 Feb 2013: the Ground temperature took a hit last week with long sequential days of overcast weather, rain and single digit temperatures, but it is still 10.3ÂșC, thankfully. The energy level is still low, and we need a sunny spring upturn soon!

The various blips of weather are shown clearly in the curve (grey all of the week just gone and sunnier the week before). Looking at last winter's lowpoint, it came at the end of a long warm 2011. The current 'low' is comparable to the low we had at the end of 2010 which had the cold winter. It hasn't been cold in the last few months, it has just been predominantly overcast - not much being put down. However - the deep ground temperature is still holding out at more than 10 degs C.
   Note, the Orange curve is the combined energy level taking into account the Sunboxes AND the GSHP. The Blue is the GSHP figure only (the solar contribution being set to zero), but this line is not totally true -  the GSHP consumption is not as much as it would be if there was no Sunbox because its COP is improved. Perhaps I should build in another option whereby the solar contribution would be actively deducted.
    I have updated my page on the ACTIVE HOUSE.ORG blog, see it at 


  1. David,

    Firstly, congratulations on reaching the final stages of the extension. I expect it will be a little strange to finally be living in something which has had such a personal input.

    I too have been struggling with the lengthy period of overcast weather as I am trying to specify a solar street light which can cope with the seemingly endless stretches without direct sunlight. Many manufacturers make bold claims but they really don't seem to get our weather!

    It's interesting to note the cumulative effect of grey but not intensely cold days being as bad for ground temperatures as a really cold snap a la 2010.

    My struggle is with battery performance, of course, and I am leaning towards Li-Po at the moment for better performance in cold, grey climes.

    1. I was beginning to hope that we were moving onto the upwards spring curve, but that was caused by a succession of two sunny sundays when I did the tests. A long grey week with rain ALL day sunday moved it down again, although staying above 10degrees. I have solar lights which almost seem to have given up, having had so little sun. One of my solar lights which wasnt working, turned out to be because the mini-solar panel had blown off and I found it amongst a pile of autumn leaves!


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