sgt_woulds

You could use something like this to control it: Single Axis LCD Solar Panel Tracking Sun Tracker Controller W/ Wind Speed Sensor | eBay UK

Fair enough 🙂 Our customer was an Econutter who was eeking out every last watt. Eventually, even he only adjusted his array twice a year. End of October and end of April from memory. In the first year he changed it daily; his panels faced slightly east of East of South, if he laid them back in the late afternoon he captured a few more rays before the sun set. Like I said, 'Econutter'. You can afford to play if you are retired I guess! These days an automated single axis tracker would be easy to set up, though

You could always look at a design that allows the array to tilt at different angels for summer / winter. We did this for a customer many years ago and it made quite a difference to his outputs - he kept daily records, and after 2 years had worked out the optimal time of year to adjust the angles which was a 30 minute job with spanners twice a year. I can't remeber the details of the frame we used but I can see it could work well with scaffold tubes as it would be easy to create a pivote around the poles.

Assuming 5x1 row then no! 5 x 1134 = 5.67m without considering the clamps (assuming approx 25mm width for each clamp that would add an additional 150mm) Best get 2 lengths at 6m. You need to make sure that you add enough support to the unistrut rails with the scaffold poles - a proposal sketch would be useful. If you have large overhangs with unsuported unistrut then use 41 x 41mm unistrut instead of 21 x 41 mm.

I like those scaffold/panel clamps - not seen them before but I've been out of the game a while. Bloody expensive though! Before MCS was introduced to extort money out of the system suppliers and legacy installers, we used unistrut for everything. My vote would be for galvanised unistrut as it will last longer than mankind. Having said that, if you don't mind a bit of surface rust after a few years then BZP will be fine. We used to get ours from CEF (2 x 21 x 41 mm). I'd use aluminium T-clamps and mount them to the strut with with short-sprung unistrut channel nuts. (the springs are a luxury but it makes locating the bolts easier). Be aware of the clamping zones for your panels - clamping outside the zones can induce stress and create microfractures in the cells. In extreme cases it can cause 'rapid, unplanned dissassembly' in strong winds...

At least if they use robots with set programs there would be less of the Great British Builders attitude of 'good enough for a Friday / Match day / customer who doesn't know better'...

Unfortunately, FACIT has just closed it's doors as there were not enough self builders who wanted to use their system and the mass housebuilders wouldn't even consider it.

Unistrut. Mechano for big boys... 🙂 Scaffold poles are harder to cut, not as easy to fit together, and you will still need a way of mounting the panels. However, if the tubes and labour are free...

Talking of screwpiles reminds of another GSHP project in London; They were using a machine to fit a vertical deep-bore heat pipe. TFL arrived and asked them to stop - less than politely but for very obvious reasons -when it was pointed out that their back garden was directly above part of the Norhern line...

I've not been able to check your calculator yet Steamy - no computer at home at the moment. Could it include occupancy levels and biogenic heat sources? I read this recently: The small passive house problem - a solution? - passivehouseplus.ie To my mind, most PH builds have been massivly oversized because it works better on paper. It would be nice to have a tool that advocates for sufficiency.

I guess my thinking was, if you have a digger in anyway, just dig a few trenches for GSHP as well. All points taken on board, and I do think GSHP has had its day. I vaguely remember reading in (I think) Green Building Magazine (great magazine sorely missed now that the deathly boring PH+ has replaced it) that someone had built a heat store under the foundations, using a tarmac drive with pipes to heat it up. Maybe it was a school - it was a looong time ago. Back then we had a lot more people willling to experiment. Back when I was installing solar (when the average system was £25000 for 1.5kw), we worked with a some fantastic experimenters and early adopters. One chap - who lived in a Walter Segal designed, and self built house - dug out his entire back garden to shoulder depth using nothing but a shovel and wheel barrow to bury his GS pipes. He was powered by Rum and Wacky Backy and was older than I am now when he started! The soil was removed by barrow to skips at the end of the lane, stored offsite, and then returned for the reverse process. Unbelivably he finished it all in a couple of months. Then he realised there was a leak and had to repeat the process...

In the colder regions of America they sometimes extend insulation out from the foundations, or create a skirt of insulation deeper than the foundations. I think this is for frost heave, but it should also make the temeperature under the slab more stable. Could GSHP pipes be layed under the raft at the same time to take advantage of this, or would removing heat under the slab cause other issues?

Talking of sums, this is a bit out of date now (I saved this about 5 years ago), but posted for further discussion: This does not include running costs. Perhaps someone here can update the MVHR / MEV costs based on real life experience. I've costed iPSV componants at around £800 for my small 3 bed, two storey house. at current prices

These only list temperatures at 1m depth, which is barely below the subsoil in most regions. We are on solid chalk and our topsoil depth is only about 300mm max. At depths of 1.5 to 2m the rock should be at stable temperature. In Hungary i've visited peasant wine cellars built into slopes where the depth above the vaulting is less than two metres and the resulting drop in air temperature is very noticable even in sustained heatwaves. Soil pipe / Earth tunnel. Same thing - just don't confuse it with the other type of soil pipe 🙂 Cooling only. I gather it is quite popular in French public buildings and schools & used by enviro-mentalists (like me 🙂 ) in California . Measures need to be taken to ensure that rain/rodents etc cannot get in. I suspect that clay pipes would work better than plastic to for energy transfer. It's not about energy gain, this is about drawing in cooled air for sustained high temperature situations where subsoil and rock maintain a lower temperature. Even a 2 degree drop from ambient air temperature can be a significant health benefit in a sustained heatwave. Could we see your sums on this? Are you talking about a planned and 'intelligent' passive stack in a well sealed or even 'passive' house or retrofit to leaky fabric? If it is the latter, then none of the ventilation options are perfect...

One of the drawbacks I can see with iPSV is hot days and sustained heatwaves with little wind to drive ventilation. Currently we 'sail' or house through heatwaves by closing off all ventilation and shading the south facing windows (curtains, but we are planning external shades when we replace the front windows). Our roof and walls contain lots of woodfibre so we have good decrement delay, and occupation is low during the day so CO2 and moisture levels are not an issue. In the evening after the sun has set and the air temperature has dropped, we open the north facing windows and the skylight and purge ventilate the house - you can feel the cooler airflow and it is very refreshing. However, after a couple of days of heat, the night time temperature difference is reduced (due to radient heat from the earth and buildings) so this option tails off and CO2 levels inevitably rise. We then use portable fans to make life bearable. I know they considered this issue with the Bedzed buildings and tried using ventilation cowls / wind catchers but I don't think it was very successful. It is pretty much a given that climate change will lead to more frequent and longer heatwaves so I'm considering building a solar chimney with soil pipe ventilation - I have to build a patio out the back anyway so it is just a little extra excavation. The chimney might be an issue with building control, but sod 'em! We'll stick it up and see if anone notices! I have a couple of ideas on the design, and I'm considering buying the Handbook of Domestic Ventilation but I don't know if this is a good sourceof information or if there is better text elsewhere. It is an expensive book to take a punt on...