Structural Insulated Panel (SIP) House

PV Feed In Tariff

noreply@blogger.com (Jonty) — Wed, 15 Jun 2011 12:46:00 +0000

It's now six months since I added a 2.1KW PV array to the house. The feed in tariff ( 42.8p unit + use all the PV energy you can) is a game changer as far as I'm concerned when comparing the costs of solar thermal with solar PV. At the half way point for the year it looks like this will generate over 2300 units of energy and pay back more than my annual electricity costs.

At the end of each quarter I submit the generation meter reading to EDF and about 30days later I receive payment.

The panels look ugly - but I can forgive them that. The system was installed by Solar Sam under the Navitron scheme. Good professional work and good system insurances come with the install. Unlike Solar thermals which drop off delivery as your tank gets hotter, PV panels keep delivering even in cloud conditions.

I used to say add PV electric once you had run out of all other energy saving measures, but now with FITS I recommend them at any stage.

(Poppies and other flowers on garage roof coming on :)

Green roof on garage

noreply@blogger.com (Jonty) — Fri, 13 May 2011 21:38:00 +0000

I have almost completed a garage, and today I put on a green roof supplied by Sky Gardens in the UK. The Verdant Blanket consists of 80 species of native provenance, chosen for suitability to green roof applications. I have bees (note the Warre bait hive full of bees in the background) which swung me to the flowers even though I know a green roof will not supply them much ... if anything. Also I'm going to be able to see taller flowers on the garage than a low, sedum type planting. The cost of the blanket, substrate (a light bark like and crushed brick mixture 80 mm), drainage layer, fleeces and river stone edging is about £42 m2. We installed in one day. (2.5 man days - my thanks to Des and David). It weighed in total about 2.5 metric tonnes or 100kg/m2.

The second picture is the 'high tech' filter fleece and drainage layer. The cups store water, and also provide a drainage path under the substrate.

The EPDM covered roof is designed for loads up to 200kg/m2, with a 200 mm up stand and 6 degree slope to a single drainage hole. Greater than 20 degrees and green roof design gets more complex. I suggest if building from new, just use ibeams and let your supplier do all the load calculations.

If I had done a simple turf roof I would have need 250mm of earth and would have needed a much higher design load. While it may have been less 'technical' than this roof, it just would not have been practical for me. It often find green solutions require technology in my builds (like the drainage layer), which I try to resist as it somehow feels wrong, but often I have to give way to the practicalities or building regulations.

Energy use in a Structurally Insulated House

noreply@blogger.com (Jonty) — Wed, 31 Mar 2010 14:16:00 +0000

Structural Insulated Panel houses have greater thermal efficiency due to good insulation properties (0.2 W/m2 K or better) and also air tightness. Below I have tried to work out how much energy was used in one year by my SIP house.

The summary is that I used about 11,000 KWh of imported energy for the year. A typical UK house uses 22,000 KWh (I expect a detached house of this size would normally use much more than this).

Imported energy splits as:

Electric = 6500 KWh (approx half not used for space heating)
Wood Burner = 4500 KWh (all for space heating - see below for calculation)

Home made energy contributions include:

Solar thermal/hydro = 1500 KWh (minimal space heating)
Passive Solar = 2700 KWh (I'm only including the special sky light window)

The split of energy is thus:

My conclusion is, while this SIP house has made a very large impact on my energy use, to go energy neutral would require a LOT more than a SIP house. I have no idea how Government targets to make energy neutral houses will be achieved unless they use some strange criteria. I would need a very large and expensive PV system to cover the gap. I've worked quite hard to get my energy use down, to do better every single detail of a house would need very careful consideration if you want to carry on living your life in a business as usual way. Maybe that is the truth of things - to have a house which is energy neutral requires us to use and consume far less.

Data for comparison and assumptions:

House area: 196 m2 detached
SIP Panels: 150mm Urethane and OSB
Location - South West UK
Occupants = 3 on average

Wood Energy
Dried (20%) wood = 11MJ per Kg. (note 1KWh = 3.6MJ) - oak/beech about 15MJ per Kg
1 m3 of 20% dried hardwood = 650Kg approx
1 year use = 3 m3 approx
Wood burner efficiency = 75% approx
1 year energy = (11MJ x 650Kg x 3 x 0.75%)/3.6MJ = approx 4500 KWh pa.

Passive Window
Based on a east/west contribution of 410 MJ m2 over a 33 week heating season the large 8x3 m2 window contributes (410 MJ x 8m x 3m)/3.6 MJ = 2700 KWh. (note window is actually inclined south facing in one direction and inclined east facing on another plane - so this is very approximate)

Solar Thermal
20 x 58mm evacuated tubes (approx 2.454m2 aperture)

Much of the data I use is from "Environmental Science in Building" by Randall McMullan. It's really useful for calculating heat losses, thermal storage, heat gain from windows, light, sound, ventilation etc. Simple breakdown of calculations and lots of worked examples at the end of each chapter. Not a cheap book, but good quality.

LED lights

noreply@blogger.com (Jonty) — Tue, 15 Sep 2009 20:56:00 +0000

My very good friend Patrick hand made one of his beautiful LED lights for me. I really like the idea of hand made electronics when normally they are all mass produced.

I always pictured the jungle plants lit with green light and then another strong color in the background, and years later it's here.

I need the plants to grow a bit more, and get some of Patrick's new wall lights. It is very hard to do justice to quality and brightness of the light using a digital camera, but this was my best effort (much brighter in real life). You can select from hundreds of different colors for the front and back of the light, quickly changing to whatever you want. Some calm, some outrageously strong and pure.

Building can be fun, but I guess it is what you are left with that counts. If you build a house I think you need to list at least 5 really strong ideas before you start, and I think the indoor Jungle is one. Things have changed a lot since this post.

To see more of Patrick's lights and contact him visit ww w.smoo.co.uk

Are Heat Recovery Ventilation HRV worth it ? (Vent Axia HR250)

noreply@blogger.com (Jonty) — Sat, 08 Aug 2009 19:40:00 +0000

Back working on the house again. This time fitting the Heat Recovery Ventilation system (HRV). It's a Vent Axia HR250 from ebay; £250 brand new with speed controller.

All houses need to be ventilated. Highly sealed SIP houses like this one need mechanical ventilation (passive is hard to design and control and cannot recover heat) otherwise you get condensation and poor air quality problems.

An HRV exchanges the heat energy from stale exhaust air to the incoming fresh air. This creates a rats nest of pipes at the HRV unit. Fresh air in, stale out, two feeds of warmed air to rooms, extracted air from bath room, small toilet room and, experimentally, a filtered cooker hood.

I've made my own control unit. Essentially it gets three boost signals to raise the unit from L1 (default trickle level) to L2 for small toilet (90m3/h @ 36w), L3 bathroom (112 m3/h @ 51w), Cooker hood (220 m3/h @190W).

The fans in the toilet and bathroom are icon 30 and icon 60 fans which automatically open when triggered by humidistats, IR sensors and lights. They each have in built timers. I disabled the icon fans and just use the boosted HRV to pull the air through the units. This makes them practically silent in operation now. Boosting is achieved with three 240v coil relays on IDC carriers in a small consumer unit, connected to 3 of the six 6 transformer taps in the speed controller (white box above). The relays are daisy chained to pass the highest boost level currently on demand to the HR250. Later I might 'break' the default L1 trickle ventilation rate if the outside air temp is very low or PIR sensor detects the house is empty.

It all works really well, is quiet and makes the air much fresher, especially in the mezzanine areas of two bedrooms which were poorly ventilated and uncomfortable before. As the fan is balanced (pulls air in while pushing the same amount out) it runs MUCH quieter than the noisy cooker and bath room fans it made redundant and more efficiently. The bathroom humidistat runs for a noticeably shorter time. The HR250 has two exhaust ducts. I'm using one on the cooker hood via a filter and I hope that stops it from clogging the heat recovery unit. I'm sure it will be OK as the cooker hood has run for year, and the pipes are clear.

Now how much energy do these things save over just exhaust fans? Well it's not easy to calculate, but here goes (making lots of assumptions):

Taking the volumetric specific heat capacity of air as 1300 J/m3K and the average outdoor temp here as 12degC, indoor temp 21degC, the designed ventilation rate for this house 30 l/s or 108 m3/h according to building regs, HR250 has a 70% efficiency.

The temperature of the incoming air is raised: 21-12 x 70% = 5.6 degC
The energy reclaimed = (1300 x 108 x 5.6)/3600 = 218W/h
Now the fan will use 51W to achieve this ventilation rate, so energy saved = 218 - 51 = 167W/h
Assuming continuous operation that's = (167x24x365)/1000 = 1,462 kWh
At 0.12p per kWh, that's £175 per year or about 750Kg of carbon saved.

Now that sounds good, but I don't run it at 30l/s, I run at less than half that rate in the summer due to high air infiltration from open windows and doors, and I use boosts when required, so perhaps the savings are going to be more? When running at lower speeds the system seems more efficient. I have measured > 80% efficiency at L1. Later, when the house is empty I want the system to shutdown, so not ventilating at all. I don't know how to calculate all these variables and you start to see why it's hard to work out the saving. I might know next year when I get my full year energy bill.

The system cost £800 when you include the HR250, ducts, vents and controls. As you have to ventilated the house to reduce condensation, smells and pollution it's definitely better than just simply ventilating with no heat recovery.

Tips:

Put a fresh air inlet close to the entrance of the kitchen to make cooking smell extraction more efficient and encourage air to going into the kitchen.
To reduce noise don't put a T duct junction closer than 1.5m from HRV unit, and use a soft Y junction.
Use acoustic ducting between rooms if there is 'cross talk' via the ducting, or for short outlet ducting. It is expensive if you get the proper stuff - it HAS to be acoustic ducting, don't accept insulated ducting with acoustic properties. This can cost 3x more than insulated ducting.
If you connect the cooker extract, disable the cooker hood fan which locally accelerates grease around the ducts and use the fan signal to demand maximum HRV boost. Use an additional in line-filter if there is any doubt about grease as this is not recommended operation and regularly check and clean the exchanger. Note as the system is balanced you will not need to run it at such a violent rate as before to get the same effect. I find the default trickle vent enough for cooking with lids on pots in summer.
Build time about 3-4 days for this job.
I choose the Vent Axia HR250, because it older technology, cheap, robust, easy to speed control, has multiple extract vents, and the company have a good and long reputation. I'm not sure the newer versions with pollen control and summer by pass filters, electronic control systems really justify an extra £1K.
In winter when the UNICO forced air heating system is on and the windows are normally closed, the HRV uses the house as a giant air mixing box. The UNICO system pushes the air to all corners of the house. I have seen designs with the HRV air inlet feeds only into the return of the forced air system to save using two sets of ducting. This really only works for forced air systems with cooling and heating ie. 24x7x365 operation. I do not use the UNICO system in the summer (The UNICO fan is 200W and I have no cooling option - not very eco!), so I need two sets of ducting. Fortunately my HRV ducting is very limited and 80% is in the loft room.

Strelitzia added to Indoor Jungle

noreply@blogger.com (Jonty) — Sat, 04 Jul 2009 21:32:00 +0000

A new friend, Len, who lives close by and found this site, very kindly popped around this afternoon and gave me some Strelitzia (plus other jungle plants) to add to the bamboo and lemon tree.

The Strelitzia (big leaf plant in the middle - click for larger view) has been grown from seed, is five years old and currently 2m high. Hopefully in a few years it will reach the sky light (5m).

This is a picture of the first Strelitzia to flower in the 'jungle'. It suddenly appeared like this overnight. In the background you can see some of the 10 lemons on the lemon tree this year. As they are very precious I save them for my favourite dishes - tarte au citron and lemon drizzle cake (made with mash potato instead of flour!)

Future plans for the jungle area include figs and avocados. It's good to start moving from building a house to using a house.

Are bamboo floors green or just yellow?

noreply@blogger.com (Jonty) — Sun, 08 Feb 2009 12:48:00 +0000

I've been putting in more flooring, and this shot is of the recently completed dining room. I have been looking for flooring and always had in mind to use Bamboo flooring as it's tough (but not as tough as a hardwood floor unless the bamboo is matured properly), looks good is relatively inexpensive, and doesn't expand/shrink so much.

There is also plenty of comment about its green credentials:

It grows very fast - 3 years to harvest, but 4-6 for harder wood.
The bamboo once cut regenerates
It can be grown with little fertilizer or pesticide

However there are downsides;

There is concern that a lot of forest is being replaced by commercial bamboo, and the bamboo is being more intensively produced
I live the other side of the world to where it's grown. I did a little calculation which suggested that the CO2 in shipping to my house was about 50% of the weight of the floor.
Bamboo strips are often bound using formaldehyde-based adhesive, which can be toxic though some manufacturers are producing formaldehyde free products.

So is it green? Probably not in my case because it's not local and in hindsight I should have asked more questions, but your mileage may vary. I'll research a few alternatives for other rooms (cork, linoleum etc.)

6kW house and Portfolio heating

noreply@blogger.com (Jonty) — Mon, 02 Feb 2009 23:12:00 +0000

Many green homes use a portfolio of heating sources as the energy sources tend to be seasonal or have limitations.

Two design goals should be achieved:

The energy system should use the greenest in preference
The energy sources should be interchangeable (eg solar needs a back up)

My portfolio is:

Passive Solar from 8m x 3m Skylight. Works well even in winter on a clear day (adds about 7degC to the house).
Solar evacuated tubes - Hot water and heating system. Provides useful input for 6-8 months of the year.
Electric economy 10 immersion heaters (6KW) . Comes on only if Solar tubes cannot fill the thermal store. Not very green, and insufficient to heat whole house when -2C Deg outside. There is also a manual 6KW boost for heavy demand.
Wood burning Stove 5KW - main source of winter heating

Click picture for more details.

While designing this, I came to the conclusion that houses should reduce their energy to use no more than that which can be supplied with 6KW energy sources. This would be tough for most older houses, but easy for new houses. Why 6KW - well many energy sources are available at that range:

2 x 3KW immersion heaters
5KW wood stoves (typical small size, which requires no additional ventilation)
Air source heat pumps
etc.

Westfire uniq 21 wood burner and twin wall flue installed

noreply@blogger.com (Jonty) — Fri, 05 Dec 2008 15:45:00 +0000

Well I finally found a Hetas installer, The Fireplace Fitters Shop Frome, who installed the westfire UNIQ 21 wood burner at a reasonable price and did a good job. I like this picture as it's one of the first showing a finished room, and I must admit sitting by the fire after the first lighting until midnight and thinking I've broken the back of the build. The picture also shows my guitar made by my friend Laurie http://www.parnellguitars.co.uk/ and my gold picture (the wall was built for the picture :). I have also put down some bamboo flooring and fitted a reclamation slate hearth.

While getting quotes to install the flue I found that all the Hetas engineers seemed to have different approaches, and some approaches fell short of building regs. Many quoted ridiculous prices (standard install quotes - regardless of effort involved) knowing that their building regs self certification would see off DIY installers who have to pay building regs over £145 ($350), assuming local building regs would accept a DIY install. My local building regs initially wanted a Hetas engineer to complete a commissioning test of anything I installed, but Hetas do not approve of this. Later they agreed a Hetas engineer was not required and they would check the install themselves. That's what the fee is for after all, but by then it was too late and I had booked somebody to do the install. My installer took a morning to fit the flue (two installers), but I did have one Hetas engineer quote 4 man days and another 2. I recommend you never accept a standard install quote and read building regs yourself first.

Building work is getting more tied up in regulations and approvals in the hands of "professional" bodies. The quality of these certified companies often leaves a lot to be desired. While I do not mind regulation and installers who really add genuine skill and experience, I think building control should always provide a service for DIYers to get their work approved and checked. Building regs for installation flues is very straightforward.

My only gripe about Flues is that very simple brackets cost a fortune. If you take the price of your stove and multiple by 2 or 3 you will not be far off the final install cost. It's worth checking online flue stores for price comparisons.

In the end we used a fire stop bracket (another amazing priced piece of metal - £128) on the exit of the flue to the SIP panel roof to ensure the twin wall never gets a chance to move out of position and close to the SIP panel and urethane (traditional houses use rafter brackets). The gap has to be >50mm. I going to monitor the temperature of the urethane, but so far so good and I believe urethane does not break down until about 200 degC. The twin wall on the exit is hot to touch, but not too hot. I'll also seal the exit hole with a ALU plate to restrict air into the flue roof hole. Using twin wall for the entire flue looks a little heavy but it improves the draw and burn removing the need for any special anti down draft cowls.

Here is a picture of me lighting my first fire. So satisfying.

Installing a Westfire UNIQ 21 wood burning stove

noreply@blogger.com (Jonty) — Sat, 22 Nov 2008 20:27:00 +0000

My latest new project is to install a Westfire UNIQ 21 wood burning stove. In the picture is the kit of parts. I'm using twin wall flue all the way (no starter pipe which is the normal way) . Twin wall will improve the draw on a short flue. The risk is, if someone over stokes the fire, it could damage the twin wall. As the fire is a back up and less than 5Kw then I think the compromise is good. The pipe will look heavy, and the brackets for these things are ugly, but function will have to win over form this time.

Before I install the flue, I need to find out about passing the twin wall through the SIP roof. I think as well as the 50mm gap around the twin wall, I'll also need a radiation shield to protect the urethane core. Sadly I have yet to find a installer with experience of SIPS, but I think common sense and caution is required. I have thought about cutting the urethane back and filling it with rockwool (still keeping the 50mm air gap). The final problem using only twin wall is you need to sweep from inside the stove. This is not easy on the UNIQ21.

The hearth is from the local reclamation yard. £55 for a nice piece of 900mmx900mm riven slate.

I mention this is a back up system. Most green energy systems need to be from a portfolio of sources as they often have strengths and weakness. In my system I have just 6KW electric on Economy 10 plus solar (passive and evacuated tubes) energy stored in a thermal store heating the whole house and providing hot water. This runs out of steam when temperature outside dips to below -2C. So a wood burner provides a reliable independent source of heat. It has great green credentials ... so I'm told ... and hopefully it will dramatically cut my electricity use. I considered an air source heat pump, but their efficiency drops off badly at -5 degrees, and they do not generate the high temperatures I need for the thermal store. I guess it could directly heat the air, and this would get pushed around by the UNICO air handler, but I wanted something that looked great, was quiet and did not use electricity at all.

TDC 3 Solar Controller

noreply@blogger.com (Jonty) — Mon, 27 Oct 2008 20:49:00 +0000

I thought I would talk a bit about the Sorel TDC 3 solar controller supplied by Navitron which pumps the water around the solar system. Essentially if the solar panel is hotter than the cylinder it turns on a relay to pump water around the system. Now this cost over £100 ($150), so it clearly it does a bit more.

One of them is collect stats, very useful, and as you can see by the picture (click) the panels produced more in October, than September, than August! What a summer. This is partly false as my heating has come on a bit in October making it easier for the panel to add heat to a cooler cylinder.

The TDC 3 has 15 different cylinder - multi panel - heat dump configuration options, stats, frost protection, variable pump control, purge settings, 3 relays, 2-6 temp probes, alarms, error logs etc. but do not let that put you off - it's really easy to use. More info here:
http://www.sorel.de/fileadmin/user_upload/pdf/BildschirmUK.pdf

The documentation gives very little information about how to optimally set up the pump speed, and there are a couple of modes for speed control (as there is for everything). I set it to variable pump speed and only start the pump with a high temperature difference between the panel and the cylinder (9 degrees) to start it and cut out when the temperature difference drops to 5 degrees. I set it like this as I have a long pipe run and I don't want a) short bursts of heat b) or lots of switching on and off which cool the tank in marginal conditions.

The other tricky thing is setting the Heat output settings (measure of KWH produced). Essentially you need to know the flow rate (difficult for variable control) and temperature drop of the pipe run. In practice you guess at these figure using a little maths and sensor figures, and then double check the KWH output with the temperature rises you see in the cylinder (use the maths in an earlier post to work out the KHW per degree rise). If the two figures do not agree, just adjust the parameters until results are consistent. The temperature drop variables are easier to figure out with the variable pump speed option turned off. It takes a while and will never be 100% accurate, but it is useful.

I think I could have got a much cheaper controller, but the information you get back from this can easily pay for itself by getting more out of your system and identifying problems quickly.

Solar evacuated tube performance

noreply@blogger.com (Jonty) — Mon, 06 Oct 2008 20:11:00 +0000

I was going to write an 'I'm disappointed' post about the solar system, but I've been gathering the data and you know what? it's better than I thought it would be. The main reason for the anticipated disappointed was the terrible summer we have had. When I checked the controller from July (when I first set up the KWH logging) the system had only produced 550 KWH in the following 3 months. Now that is only £53 ($106) of electricity saving over a what should be a good 3 month period. I remember in an earlier post hoping for a minimum of £150 ($300) saving for a whole year (cost of the DIY install was just under £1500 - but could have been lower if I knew what I know now).

But then I starting thinking ...

Considering how bad the summer was (there were no clear days in the measuring period!) then we could have been looking at a minimum of 1100KWH for summer.
The end of September produced one of the best days (8KWH) - when the heating came on, and created more "room" in the cylinder for solar energy. In other words, sunny cold days produce more than hot days when the thermal store is full. This also explained the amazing return in April when I tested the system with a COLD tank on what turned out to be one of the few (only?) clear days of the year. So still more return to come in the winter.
I didn't fully lag the pipes until the beginning of September and fixed a leak which had reduced the pressure. This meant that I actually produced more in September than August.
Today electricity went up 20% (second rise this year) that £53 ($106) of electricity will cost £64 ($128) next year!

So I think perhaps I'm on track to make over 1500 KwH, £150 ($300)of saved electricity or better still 750Kg of carbon saving, despite the poor summer.

So worth doing - yes - but my special shower head http://www.mysiphouse.com/2007/07/sip-house-green-thing1_07.html still head wins hands down for green credentials. For a large family it can save just as much, but for just a £30 ($60) investment.

What have I learnt?

Lag pipes... Lag pipes!
Position the panel and the boiler as close as you can. With a total 50m pipe run I'm losing around around15% of the energy I produce even with 13mm lagging (except winter when it helps heat the house on the way to the cylinder)
The greenest things you can do are not the big ticket items
I didn't just buy alocal organic chicken because of payback. Some things should just be done because they are right

Building Control - nearly there

noreply@blogger.com (Jonty) — Tue, 24 Jun 2008 14:10:00 +0000

I remember someone saying that building a house was like going on a train ride with no stops on the way. So true, but last week I called in building control for my completion certificate and apart from a cooker hood and small mods to the space saver stairs I'm nearly at the destination. I'll need some nice floor coverings - but after everything that's gone before it will be a minor detail. I think I'll use 15mm bamboo flooring. Apart from the distance it is shipped it seems as green as you can get. I looked at cork, but found that really hard to supply. Some of the new cork flooring is fantastic, and so much better than the 70's cardboard style tiles. My dad fitted cork when I was a kid in the kitchen, claiming it would reduce breakages ... not so I can report.

The picture was taken in June - a bit over grown on the grass front - but it's the only "building" work on site that gets done with no effort on my part. New additions include finished decking on the east side. You can see the aluminium angle eaves - I hate painting, so powder coated ALU angle seemed to be a great and under used method for finishing edges. Also on view are the inlet and outlets for the ventilation, and the Japonica moved back to the front of the house. I moved it away from digger peril during the main build. I used a tree spade to move it away (15 minutes), and three hours of digging by hand to move it back.

First day of operation for Solar panels

noreply@blogger.com (Jonty) — Thu, 10 Apr 2008 19:05:00 +0000

First day of operation and another frosty start. The day ended cloudy and as this is April the sun is still low, outside air temp got to 9 degC, so I'm not expecting boiling water. Also the pipe runs are 49m and only 80% insulated atm.

Still, the results are good! Starting temp of cylinder was 20degC and the cylinder is 280 ltrs. At the end of the day the cylinder was 48 degC - Enough for a very..... long hot shower. A few calculations gives:

4.2 x 280ltrs x (48 -20)temp rise = 32928 KJ (or 33MJ)
33MJ / 3.6 = 9.3 KWh

(hmmh ... looks a bit high, possibly stratification of cylinder makes calculating the average temp rise inaccurate?)

The total capacity of the thermal store at 70degC is 16.3KWh, so if the figures are correct I'm impressed.

On average a household uses 50ltrs of hot water per person per day, or about 1.5 kWh at 55degC, so even on a cloudy April day I have hot water for 3 and a contribution of 4.5KWh to my heating (the thermal store cylinder does heating and hot water). As I also get a lot of passive heating from the skylight, so I can turn off the heating on sunny but cold days like this.

Before I get carried away, 1kWh costs about 5p on economy 10 (12p peak), so that's only about 45 pence saved today. I have to use some peak electricity for heating in winter, so although the contribution will be lower, the per KWh saving will be much greater, and I'm hoping to save £150 to £200 a year. The pump was on for 9 hours and controller 24x7 but that's not much energy compared to the gains.

Think of all that CO2 saved today (9.3 x 0.43Kg = 4kg). 1kWh electricity produces 0.43Kg of CO2 according to National Energy Foundation.

Shower was good, seemed identical to a .... normal shower, funny that.

Things can only get better.

Solar tubes fitted

noreply@blogger.com (Jonty) — Wed, 09 Apr 2008 20:03:00 +0000

This shows the first 5 58mm tubes fitted, and yes they are covered in frost. You might just notice the simple air vent arrangement on the left of the manifold by the cold inlet. The hot return doubles back on manifold and the vent pops up by the cold inlet to the manifold. I did this to position the air vent 1.8m ,following the copper pipe, from the manifold to prevent the tiny rubber seal from melting in extreme conditions. If that does not work I'll use a different seal material (leather?) as it's a simple disk. Having the vent in free air, and having it drain to the roof and gutter also helped. I fitted the rest of the tubes that night, but during the day just the five tubes worked for 2 hours on a cold April day when the outside air temperature was 8 degrees.

As I haven't filled the pipes with Antifreeze yet, I set the controller to circulate the water if the manifold got to 3 DegC. Well it did! so unlike every other post saying on my first day I had a nice hot shower, I can say that on my first night I lost energy :) Ah well not much and I found it funny. The controller poped up a little information alert warning about it for me to read in the morning - so at least I know that bit is tested.

Plumbing in the solar Panel

noreply@blogger.com (Jonty) — Wed, 09 Apr 2008 19:34:00 +0000

This shot shows the only 'complicated' plumbing. All it does is pump the water/antifreeze mixture from the solar coil in the cylinder back up to the solar panel for heating up again.

Rather than plumb the tricky bits for the solar panels in place I decided to mount them on a board, and then fit the board into position when it was mostly done. Connecting this to the system was simply a matter of connecting to the return from solar coil (lower of the two coil connections) in the hot water cylinder and the other end to the cold return at the panel. The rest of the plumbing consists of the hot return from the panel to the solar coil inlet (higher of the two coil connections)

The picture (click for more detail) shows the pump and expansion vessel. The solar controller sits on top of the pump (not shown) inset into the polystyrene insulating casing. The parts were purchased from Navitron and consist of a flow box 700 + TDC3 controller and a pressurised system kit. Short points to make on this picture are:

Just above the pump is a clever one way check valve with several features. The check valve stops thermo-siphoning at night (solar system working in reverse). It contains a slot for a temperature gauge (not fitted in the shot). The valve can be twisted during commissioning so that the pipe work both sides of the valve can be filled (saves having a by-pass pipe and commission valve).
The expansion vessel keeps the system at about 1.5bar, so no header tank is required for the closed system. A combined filling tap and 3 bar pressure release valve is fitted. The pressure release is an important safety feature and in the final system a vessel will be added to catch any fluid if the release valve trips.
I added two simple air vents - I really only needed one, and that probably could have been an auto-vent, but I didn't have one handy.
The pipes need to be insulated with ARMA flex insulation, but I guess the return piping is not quite so hot, so I guess cheaper insulation could be used here, at your own risk. Most DIY shed insulation melts above 70degC.

As I mentioned earlier I hate compression joints - this had three weeping joints when I connected it up. Duh! I'll use fernox pipe sealant next time.

Solar evacuated tube installed on roof

noreply@blogger.com (Jonty) — Tue, 25 Mar 2008 21:00:00 +0000

Yikes! I underestimated this task. SIP roofs have a construction of SIP panel, membrane, vertical batten (for ventilation) and horizontal batten for the tiles. This means you cannot run the pipes into a loft space, as there often isn't one on a SIP house and you have to run the pipes between the battens as shown in the picture (click picture for more detail).

That might not sound difficult, but all the plumbing by the panels has to be compressions joints (I hate compression joints!) as the temperatures within 1 m of the tubes could melt solder joints in failure conditions (solar stagnation).

Then there is the air vent problem ... what a pain. You want an air vent at the highest point (right next to the tube's manifold) but nearly all air vents have plastic components which can melt if placed close to the manifold. I solved this by putting a thumb screw vent on the hot water return just where it runs past the cold inlet on the left (1.8m from the hot outlet and in free air). I poked it out of the roof because there was nowhere to run it inside the house, and on the outside so it can at least vent to the roof and gutter while I'm filling the system. This means four holes in the roof tiles (thank god for diamond cutting drill bits) : cold inlet, hot return, temperature sensor, and air vent.

Things to remember next time - get a bigger hole cutter (4mm bigger than the tubes), the extra tolerance makes fitting pipes to tiles easier and also easier to push silicon deep into the joints.

I'll add the tubes at the very end when everything is working.

It's not as steep and I'm not as spider man as this picture looks.

DIY solar evacuated tube install

noreply@blogger.com (Jonty) — Tue, 25 Mar 2008 20:41:00 +0000

Looks like this will be green thing 10 out of 10. I ordered from www.navitron.org.uk a 20 tube solar evacuated solar collector. Ordered on Sunday and it arrived Thursday, and here is a shot of the kit waiting for me at the front door.

Perhaps the design choices for the solar panel might be useful. The system will be used to heat a 280 ltr thermal store (with solar coil in-built) used for heating and hot water. Thermal stores operate at much higher temperatures (70C deg) and volumes than normal cylinders. So design decisions are:

a) Evacuated tube - gives some winter contribution and overcast/low angle contribution
b) 58 mm tubes (larger than standard 47mm) for 50% extra performance
c) Flow box 700 + TDC3 controller as I need to heat the cylinder to its limits and therefore control is important.

The control system and heating contribution ruled out flat panel designs pumped by solar powered pumps. The parasitic losses from the pump and controller are outweighed by the extra solar heating contribution.

I'll mention one thing about the picture and that is the flexible aramaflex tubing. You need higher temperature insulating tubing as normal DIY tubing often deteriorates at 70C deg plus range.

More install posts later!

Green thing 9 out of 10

noreply@blogger.com (Jonty) — Mon, 03 Mar 2008 22:34:00 +0000

I've been slipping on my posts, and struggling to reach green post 9 out of 10, but here it is - Changing air only when I need to and via a heat exchanger.

These two pictures show the fans in the 'wet' rooms (bathroom,toilet). The wet rooms each have a exhaust fans and these are connected together. They can be set to trigger on humidity (bathroom) or light on (toilet room which has no window - and hence automatic light and suitable trigger). As the humid air exits the building it does so via a passive heat exchanging, passing the heat from the exhaust air to the incoming air.

I chose the AIRFLOW Icon fans as you can have different trigger modules (IR, humidity,trigger) and they look so cool when they open ! The Icon 60 is a bit noisy and big for the bathroom, but its really powerful and clears the air in seconds. As its only on when the humidity is high, it comes on only at the end of my shower.

One of the Icon fans failed after 1 year. AIRFLOW have a 3 year guarantee and they changed it straightaway.

I'm thinking of connecting the Icon 60 to the C02 monitor to assist with forcing air out via the heat exchanger as I suck in fresh air using the UNICO air handler (or a smaller in let fan to save energy.) Something I'll experiment with in the summer.

UNICO heating and cooling

noreply@blogger.com (Jonty) — Sat, 27 Oct 2007 17:41:00 +0000

If you look very carefully you can see the heating/cooling system in the ceiling of the dining room (Top left and the rectangular slot ... click the picture to get a bigger view). This time I've 'boxed in' the ducting.

This shot was taken hours after the walls got their plaster skim. In my system, the UNICO system uses a single hydroponic radiator in front of fan and ducting system to heat the house.

On days when it is too hot the system blows cool air from the shaded north wall. A further modification to the UNICO system (under development) is a CO2 control system to add fresh air when needed. So far the CO2 levels are too low to trigger a control valve. Another addition to add is a passive heat exchanger to transfer the heat from exiting stale air to the incoming fresh air. The heat exchanger and Co2 monitor can be green thing 8 out of my 10 and we shall call it "Only change the air when you have to".

So when I have finished the UNICO system will provide:

Heating
Cooling
Air quality control
Passive heat distribution

Green thing 7, no skips

noreply@blogger.com (Jonty) — Sat, 27 Oct 2007 15:30:00 +0000

It's been a while since I uploaded a current picture of the SIP (structural Insulated Panels) house, so here is a picture. We could call this green thing 7 as its shows no skips. Where possible I use everything. For example, where I use to two layers of plaster board to create wiring channels, the first layer is all the off cuts. Broken tiles are used for rubble under the decking and the list goes on. It is time consuming, but I guess thats why people create so much waste. We are all in a hurry.

Efficient cooking: Green Thing 6

noreply@blogger.com (Jonty) — Sat, 14 Jul 2007 13:40:00 +0000

Everything helps and fits together. This is an odd picture of the induction hob. Hobs like these are 40-70% more efficient than other types of hob (halogen, electric and gas being the worst) and safer also as the pan gets hot and not the hob. They work by creating eddy currents (magnetic fields) in the pan. So all the energy goes to the right place - and not heating up the kitchen (which is not good in a super insulated house!). The heat is extremely controllable.

LED lights: Green Thing 5

noreply@blogger.com (Jonty) — Sat, 14 Jul 2007 13:31:00 +0000

These are great, LED lights. Green facts are:

2.4 watts (similar light to 25W GU10, or 7W low energy fluorescent)
Instant on (unlike slower low energy fluorescent cousins)
Very low heat (safer)
12,000 hours (much longer than the fragile low energy version).
Cost about £7 each

Thermal Store: Green Thing 4

noreply@blogger.com (Jonty) — Mon, 09 Jul 2007 18:40:00 +0000

Ah my love ... my thermal store Betsy. Looks a bit complicated but basically it stores energy in a big water cylinder (nothing new there I hear you say) and releases it to the cold water supply via a heat exchanger (slightly different). Three supplies of energy, with the greenest and cheapest at the bottom of the tank; solar connection, further up economy ten elements, and then for those really cold days when everybody wants showers standard rate boost elements (not used very often!).

Passive solar heating. Green thing 3 of 10

noreply@blogger.com (Jonty) — Sun, 08 Jul 2007 08:00:00 +0000

The house gets lots of heat simply from the skylight. Most days it is 7 deg C warmer inside just because of the passive heating and insulation.

During the summer this can get too hot so the ventilation system can bring in cool air from the shaded north wall and the 3 folding sliding doors allow the roof to act as a shaded canopy

Post a comment if you know the name of the plant in the first picture!