Images

Peveril House in December 2012
with Surya wall-mounted Sunbox mark 3, the roof-mounted mark 4
and the Kingspan Tubes.
Introduction: Here is a view from the South East of the Peveril Solar house. At the left you see the two Surya Sunboxes, one on the wall and one mounted on the roof of the house extension. Those are putting solar and air warmth into the borehole below the site. On the roof surface, you see 28.8 sqm of Photovoltaic panels supplying electricity and 2 sqm of evacuated tubes dumping warmth to the borehole. On good summer days, this combination can dump up to 59 kilowatt hours of solar energy into storage in a single day.

Surya 3
Since August 2011, the large upper Surya Sunbox is a single compartment, and now has a sloping front. It was constructed of insulating triple wall polycarbonate and has nearly 3 times the air volume inside. This worked better than the vertically fronted boxes - the polycarbonate is still too filtering of solar energy, so since Aurumn 2012, the current model (above) has front panels of ETFE double skinned. This is so effective for solar thermal transmission that the sloping front is unnecessary, and I might rebuild it in a future time as a vertically fronted Sunbox.
(There was an intermediate design proposal called Surya 2, but this was built as a prototype but not erected or pumped in.)

Surya 1
The first Sunboxes dating from March 2010 were vertical, only 200mm deep. Being south facing, they pick up sun during the middle hours of the day, if it is visible, and the vertical orientation makes them more effective in winter! Because they work better with a large airspace next to a surface with high thermal capacity, they work better on the wall than they would on the roof. The Mirrors above the sunboxes were added in mid-September 2010, and foot mirrors were added in mid October.
 (There was an intermediate design proposal called Surya 2, but this was built as a prototype but not erected or pumped in.)
Surya Sunboxes mark 1
Evacuated Tubes
Since March 2012, we also have 15 Kingspan Varisol evacuated tubes on the roof, 2 sqm. The idea is to compare a high-temperature-low volume collection with the low-temperature-high-volume collection of the existing Sunbox. The result is mixed. It proves that the Sunbox idea works better for ground charging. However, it's possible that a larger array, such as 4-8 square metres might have enough solar capture to make an effect.
  The impact of cold glycol being passed over the tube heads tends to tell the controller to stop the pump. We now have a metal heat exchanger that delays this effect and gives longer hours of running.
Kingspan Varisol Evacuated tubes

Cutaway view
Below, is a model of the roof with much of the house cut away, to show the Sunboxes, Plumbing and Electrics and the heatpump below. The rendering also includes the 'Mirrors' which were added in Sept and Oct 2010.
  In addition, there is a Suntube that brings light from the West roof into the central landing. downstairs.
  Its usually better to put working rooms like a Utility room to the north, but on this occasion it necessitates long pipe runs from the south wall. But at least we didn't have to find somewhere to put a giant intermediate water tank.
If I switch the camera view round, I get a great view of the reverse of the panels and all the plumbing coming into them (with the wall removed, for clarity).
The pipework is all insulated of course, firstly to reduce system losses. Secondly, they could be dripping with condensation when the heat pump is working very hard in the winter, and the condensation would be a major problem.
See System Tab for explanation of the difference between Sunboxes and Solar Thermal panels. The black collectors are SolarFocus swimming pool panels, of 1 sq metre each.
This image from October 2010 shows the boxes with solar reflectors above and below the sunboxes. The SBs are already pretty successful, but Hey! this is a Research Rig, so we have to try everything. The upper ones should have little effect when the sun is high, but in Winter, there will be an additional square meter of panel facing the Sun, reflecting solar heat downwards to warm up the airspace. The bottom mirrors are tiltable seasonally, to optimise the reflective sun angle at all times of year.

For images of the internal plumbing, please see the Blog page:
http://chargingtheearth.blogspot.co.uk/2012/05/plumbing-circuit-update.html

This picture, taken on 30th September 2011 at about 10am shows the Surya-3 Sunbox working well. In the month this was taken, the Sunbox recorded >80kWh in a spell of four days. The previous boxes recorded >20 kWh in one day only on five occasions in 17 months.End of Oct 2012: The Sunbox has been re-fronted with ETFE, Ethylene Tetrafluoro Ethylene, a miracle thin plastic that is supposed to be transparent to solar thermal energy - although it is not perfectly optically clear. The panel is double skinned, thermally stretched.




The house extension now supports a roof mounted Sunbox, based on two metal radiators inside a polycarbonate sunbox, and it also has a single 200W Photovoltaic panel. 
The PV panel is 800mm x 1600mm. It needs to be raised on legs to reduce the shading risk.
The PV panels is charging a battery of NiCad cells in the loft, with a theoretical capacity of 160 Amp-hours. These are providing power to a number of appliances in the loft, chiefly the 72W water-pump powering the Kingspan tubes system.
Actually, since early 2015, the Kingspan tubes are disconnected, and I have added a commercial deep charge battery as I could not get these to hold charge. 

Popular Posts

There was an error in this gadget