June 2010, great month for sun

[dhaslam]

Despite quite a lot of variation the average daily output was 18.4 kWh, 42% more than last June.   Highest output was 39kWh which was 50% more than the best day  in June 2009.     There was very high usage which boosted to output  on the best day, similarly  in May output once reached 37 kWh.   

[StBarnabas]

DH
I don't have figures I believe for my solar water system, but it has been a very good June for PV. In the three months April-June I have made almost exactly 1000kWh, at this rate OFGEM will suspend my account under suspicion of cheating!
Sean

[desperate]

Sean

You'll be joining the Megawatt high club next

Desp

[noelsquibb]

Warmest June for 80 years apparently,  so we ought to be seeing a good power and heat harvest.

[desperate]

Strangely though the highest temps I have recorded so far were back in april when the airlines were all shut down, I wonder how important transparent air is? dunno what the relantionship between temps and energy on my system are though.

Desperate

[desperate]

Strangely though the highest temps I have recorded so far were back in april when the airlines were all shut down, I wonder how important transparent air is? dunno what the relantionship between temps and energy on my system are though.

Desperate

So to that end I thought I'd do a little sperryment today. I've often wondered exactly what the energy input to the hot water cylinder is on our system, so to get a pretty accurate measurement this morning after various demands on the water were satisfied, I drained all the hot water out of the cylinder Eventually the top and bottom readings were the same at 22 deg c. Then the temperature rise was recorded as so

Time     S1        S2        S3
10.20    28        22         22
10.30    28        24         24
11.08    34        27         27
15.07    59        53         53
15.30    62        56         56
16.00    62        57         58
16.30    66        59         60
17.03    66        61         61
17.20    66        62         62

So by my reckoning for a 216 litre cylinder that works out to an input of just a smidge over 10KWh, and an average power input of 1.42KW for the full seven hour period. For the more interestind period between 11.08 and 15.07 we have an input of 6.55KWh at an average power of 1.64KW.

I think that aint 'alf bad considering we had a pretty milky sort of sky with lots of high level cirrus/Plane smeg, for at least a couple of hours, and that is of course after  all the heat losses in the solar loop pipework and control bumf.

I am currently buying gas at 3.9pence a KWh, so allowing for heat losses in the gasser/heating system that represents a saving of 50 pence at least

One day I will get the heat metering system up and running  and then we can see how it goes all the time.

Keep on rocking in the free world...............

Desp


OOOPPSS........stupid me ...it's July

[desperate]

DHaslam

How do you measure your heat input? your peak harvest of 39 KWh seems like an unacheivable figure for me I think we have broadly similar systems?

Just curious

Desp

[dhaslam]

The output  is directly from the controller.    It seems to be accurate at low  output figures  because the  reading wakes sense compared to the usage but  is does seem to be a bit optimistic at the highest output.     On the higher of the two days with very high output there   would have been  nearly 700 litres of hot  or shower temperature water used, total water usage  780 litres for 24 hours.     In addition the heat dump was transferring  heat to the buffer tank in the attic almost all day.  I put the transfer pump on full speed to transfer heat more quickly but once the temperatures are similar the pump just stays running until water is used.  If the water used was heated on average by 25 degrees the usage would be about  20kWh and  both cylinders would lose  three or four kWh  plus about the same from the pipework between the two  so it isn't all that far out.                   

[noelsquibb]

Get a government economist to do the calcs 

[KLD]

Desp

as long as there is none or very little HW drawn off during the day, measuring the temperature increase in the tank provides a pretty accurate way of calculating the thermal energy. Data recording-wise I'm only a small step ahead of you, with four 1-wire sensors in pockets along the height of the tank, and readings taken every five minutes. Installation-wise you are 50% ahead of me, with my 40 toobs against your 60.
I've measured just over 1kW peak input into the TS for our system, so your 1.5kW seem entirely reasonable to me. It also agrees with the data on the SPF site, where they reckon 550W per 20tube panel.
Same goes for day totals, the best so far was 8kWh.

Interestingly, when you calculate the monthly total (in June I had 130kWh) and say that is for a 1.1kWp system (in photo voltaic speek), then you get very similar figures as are reported by the 'lectron counters.

Klaus