Saturday, March 26, 2011

March heat wave!

26 Mar '11: We seem to have had an astonishing run of sunny days, with all the students at the Uni wearing summer clothes, tutorials taking place on the lawns and even on the flat roof area. Back at home, the PV roof has been recording good scores every day. I also notice that the Sunboxes have been doing well, with their score being 90 kWh more than the PV roof since the start of the year (450 as against 360....) and with a week to go to the end of the first quarter!
  Today, the PV roof has just passed 4000 kWh (since installation), and the Sunbox meter hit 13,000 on the same day. As it started with a few thousand on the clock, that is merely a coincidence - the real count is that it passed a figure of 3,000 two weeks ago, and is romping ahead, consistently harvesting more kWh per day than the PV - unlike the way it performed last year.  The GSHP sits idle for much of the day, its consumption per day being less than 10 for the whole of last week - it has been a total of 48 kWh for the last week which is good for a week in March.

28 Mar '11 Postscript: Following the weekly summary on Monday, the system here is again breaking records for annual performance. There are four main summations each week:
  • the House meter : Record Low! 5,555
  • the GSHP meter : Record Low! 3,564
  • the PV meter : Stabilising at 3,250....
  • the Sunbox meter : Record High! 2,982
We don't have a grand slam of four, because the PV annual maximum ever was 3,325 kWh last October, and currently it is stabilising at around 3,250 kWh per annum. April 2010 was extremely sunny and if April 2011 is not as sunny, the annual PV figure will go down :(
  The underfloor heating circulating pump draws its power from the electric supply to the GSHP so that is adding an apparent 250 kWh or so to the GSHP's consumption figures.
 As the best (highest) PV annual was 3,325 and the best (lowest) GSHP is so far, 3,564, we are only 240 apart before we close the figures. As the underfloor circulating pump uses more than that, we are Carbon Zero now for heating AND hot water, so we now need to improve efficiency further to include the floor pump. That is less than one kilowatt hour per day, over one winter between September and April - Let's do it!

3 April postscript: Here are updated charts for ground temperature and degree-day to heat pump comparison.

No comments:

Post a Comment

Comments will be moderated before showing. Please make them relevant to the subject of the posting. Comments which advertise commercial products will usually be deleted.

Popular Posts