Sanicompact43 – the ultimate toilet

It’s Saniflo‘s Sanicompact 43— a very superior toilet in every way.  It’s high quality ceramic; it’s almost silent; it’s about the most waterwise-efficient toilet you can get… and it took less than 5 minutes to install in the yurt!  And it has a soft-close lid & seat — you just tap it and it slowly closes on its own.

CapeInfo’s requirement was that the yurt — and all its services/utilities — should be completely independent of municipal services.  Using a biodigestor also means that nearby waterways or underground water is not impacted at all.  The moment one connects to municipal services or installs a septic tank, some approvals are going to be necessary.  A composting toilet wasn’t an option — waterborne sewage is the norm and composting toilets are often associated with flies and smells.

Sanicompact 43 – the inner workings and the power plug, water inlet and blackwater outlet connections. It has no cistern.

It is… as far as I know… the only toilet suitable for this application where blackwater is treated by a biodigestor — for the following reasons:

1. It uses only 3 litres of water for a full flush; 1.8 litres for a half flush.  A conventional toilet uses at least double that and will just flood the biodigestor with water, reducing its efficiency and necessitating a far larger biodigestor.
2. The toilet can be used where  conventional gravity-draining is impossible.  The toilet pumps the blackwater to where it needs to go — in this case, up into a biodigestor above the ground alongside the yurt.  Since it includes a macerator, the biodigestor’s process is speeded up.

It’s usually marketed as the solution for adding a toilet to any room in the house, without requiring major construction or renovation.

I was worried that the 550 Watt pump/macerator, along with the 370 Watt water pump, might be too much for my solar system — 300 Watts of PV panels, 3 x 105Ah batteries and a 1.5kW inverter.  Saniflo’s motor must be very efficient because it made no impact on the solar system at all.  It’s usually the start-up spike that challenges batteries and inverters.  (The fridge only uses 55W but its startup can reach 860W.)

The Sanicompact is not cheap!  But if one considers savings in installation, construction and plumbing costs, lifetime water savings… and — if one uses a biodigestor — no municipal blackwater connections, it is a no-brainer.

Plumbers (and Saniflo) would probably be horrified at the yurt’s installation… but then it is a tent and can be moved quite easily.  We used ordinary Class 3 black irrigation piping and the standard plastic fittings associated with that.  It can’t get any cheaper.

Installing the Sanicompact in the yurt was a matter of connecting the unit’s outlet pipe to the biodigestor, the water inlet pipe to the greywater system, and plugging it in to the electrics.  I spent more time thinking “Is this all there is to it?” than it took to install!  It really is “plug and play.”

The biodigestor: The bottom tap drains liquid fertilzer, the tap on top is the gas outlet and the blackwater input pipe is lying across the top of the tank, ready to be inserted into the tank.

The tank cost about R200 from Peninsula Drums and all the other fittings are from Overberg Agri and cost about R100.  So… blackwater sorted for about R300!  And all byproducts can be re-used.  What on earth are we doing pumping all our effluent into expensive reticulation to expensive sewerage treatment works kilometres away?  And unlike septic tanks, there is no danger of polluting groundwater.

In 1980, India had over 9 million biodigestors in operation.  Today the number can’t be counted because they are even found on apartment balconies, primarily for organic waste to provide cooking gas for the inhabitants.

My solution took less than an hour to make.  I cut holes for the liquid fertilizer and gas output pipes, and inserted tank connectors with taps.  How to get the tank connector into the drum?  Take a very thin piece of wire and insert it into the drum and guide it to come out of the hole where the tank connector has to go.  Feed the tank connector onto the wire and pull it into the hole, where it needs to be tightened.

For the blackwater input pipe, I cut a hole into the one screw top, inserted the fittings into it and connected a piece of PVC pipe.

The other screw top remains to be used for organic waste and checking levels inside.  Once the biodigestor starts producing gas, a similar but shorter pipe will be inserted to stop gas escaping when organic matter is added.

The drum should be painted black to prevent algae-producing UV rays penetrating the drum.  (If that happens, your methane will be replaced by carbon dioxide.)  I’m going to wrap the drum in thick black plastic which I already have.  Bear in mind, the biodigestor needs warmth, so it’s located on the sunny side of the yurt.

Here are two videos which will tell you everything you need to know about biogas units:

You can also buy recycled flowbins from Peninsula Drums – really quite a remarkable award-winning company.

The biodigestor is only possible because of the Saniflo Compact toilet.  Firstly, it macerates and pumps the effluent to the drum.  The drum can be above the ground.  Secondly, the Saniflo unit only uses 3 or 1.8 litres of water per flush, compared to the normal 6–10 litres of conventional loos.  The biodigestor tank can be much smaller and is far more efficient with lower water volumes.

Now, all the unit needs is some blackwater and a bucketload of cow manure to kickstart the anaerobic process.  It takes about a month for gas to be produced, or less since the blackwater is macerated.

I scrambled up to fetch my dog and rushed him into the vehicle for safety, and caught my breath. My mouth was bleeding badly -from lacerated cheeks and lips. (Later I discovered my body was covered in the worst bruises I’d ever seen.)  Looking back at the yurt, it was gone…

DEVASTATION: The yurt was blown right off the platform. The walls were flattened.  A quarter of the floor had been ripped up. The yurt’s contents were spread across the field.

This was a traumatic night. On my first night back in the yurt after it was rebuilt — during the next storm — I understood the real meaning of Post Traumatic Stress Disorder (PTSD). Every time I closed my eyes to sleep, I saw the roof disappear, or the door come flying towards me, or a gap appear between the wall and the floor, or, or, or….  I had to open my eyes to prove it wasn’t true. Fortunately that didn’t persist.

Peter Kastner let me stay in the “Trailer” — a whimsical place to stay — while I regrouped and gathered my thoughts.  I kept asking myself, “Am I arrogantly trying to achieve the impossible?”  Can I really beat the wind and Mother Nature?

So I made a plan and — before I outline that plan — I’ll give you the answer.  I can’t beat it but I can cater for it.  The yurt has withstood two more storms now, one reaching wind speeds of 121km/h.  During the one shown below, the inside of the yurt was a sea of calm while noise raged outside.  The walls hardly rippled, and — most times — there was just an occasional lazy flapping on the roof.

Forecast on the Windy app: the winds on the mountainside are almost permanently the magenta-coloured gust speeds shown above… or more!  The wind comes barrelling down the mountain kloof that opens into this “idyllic” copse of trees.  In the time I’ve been here, two trees have blown over.

Firstly, a note of warning about the Windy app.  It’s not wholly accurate but it is good for warnings.  It shows the same weather in the village as on the mountainside where the yurt is located.  But while Stanford can be quite pleasant, the yurt can be buffeted in a gale.   Even 200 metres down the mountainside, a howling gale turns into a light breeze.

What was the plan?

A (more) level floor
Given the total devastation, I had the opportunity to rectify one problem — levelling the floor.  The slope on the first floor just encouraged the yurt’s structure to slide off the base.  Just after I erected the yurt and before I attached it to the floor, I woke up to find it had just slid off its base in a medium wind.  That’s when I realised how light the yurt actually is.  The total weight of the walls, covering, rafters and roof ring is only about 150Kg.  So the weights on each of the 16 points where it meets the floor is less than 10kg at each point.

Make it as air tight as physically possible
This was a big issue and I had to address several components:

The Roof Dome
I had wanted to get a plastic dome like Yurta has, but there are long lead times getting one made.

The roof dome on Yurta’s yurts

The camera decided to do it’s own thing… creatively. It still gives an idea of what the roof light looks like.

I had been using a translucent sheet of tunnel plastic tied to stays in the ground.  This worked well because it was easy to open and close, although it was challenged in strong winds.

I needed a fast solution that would be totally air tight.  So I bought a sheet of 1220mm square 9mm plywood, cut a circle and the opening to match the roof ring, and glued a sheet of tunnel plastic onto it.  The seal is a strip of self-adhesive foam rubber (used for door jambs).  Four bolts hold this tight to the roof ring.    It works brilliantly!  And if you are going to be using the yurt for camping trips away, it’s far easier to transport.

It can be opened and closed — with some effort because you need to use a ladder to get to the roof — and the ideal solution is for it to be attached by a screw jack which can be opened by a long pole.  I couldn’t find any locally.

A screw jack

The issue of the door’s position
Everybody I spoke to said the door needs to be at the opposite end to where the bad weather comes from.  I said that the door and its frame, if they are the strongest elements in the yurt’s wall, need to anchor the yurt against the bad weather.

So the door is more sturdily connected to the wall than it was before, and it’s also anchored, at the top and bottom on either side, by wire stays connected to one-metre steel posts hammered into the ground.

In addition, and to make using the door during a gale still possible, there’s a 3m wide x 2m high wind deflector.  It’s basically two sheets of shade cloth between wooden posts.  (I’ve read of people doing this with broomsticks and stays, but I wasn’t taking chances.)  This has worked well.

Sealing the wind gap between the walls and the roof.
I’d used some bubblewrap as insulation against the morning sun, which was wrapped over the tension cable to form two layers hanging down and wrapping under the floor.  This formed a fairly tight seal against the roof and seemed to be the solution.

So I applied this to the entire wall and in light winds it seemed to do the trick.

Bubblewrap hung over the yurt’s steel tension cable to create a better seal.

Then, while I was writing the previous story and waiting for the first real storm to hit, I looked at the pictures of traditional Mongolian yurts I used there and thought… wait a minute… I’m missing something — the rope bands around the yurt.  So using existing rope and the eye-hooks in the door frame for the wire stays, I wrapped two lengths of rope around the yurt diagonally.

As the winds rose… there was no flapping and almost no wind entering the yurt.  So I rushed off to buy more eye hooks and more rope, and now have three lengths of rope wrapped around the yurt for really bad weather.  The windows can’t be opened when the ropes are in place, but I really don’t want the windows open when there’s bad weather.

The yurt is now probably more draft-free than any house I’ve ever lived in.  It’s a sea of calm and totally drama-free while the wind roars outside.  It’s bone dry inside even in the heaviest downpours.

I think the project has been a success… even if it did take its toll on me!  It has been tested under the most extreme of weather conditions.

There’s still a really unique bathroom to share with you!

And it’s a structure that one person can pack up and re-erect somewhere else within an hour.  But it can also be as permanent as you want it to be.  In North America, yurts have become popular as permanent homes because of the rising costs of conventional housing.

What if I told you it doesn’t need municipal building plans or approvals?  It’s a tent!  And if you erect it as guest accommodation, AirBnB tells you that it’s been their most popular specialist sub-category worldwide?  That it would make an ideal yoga studio, or info office, and those who have seen it, wished they had one to take to music festivals?

An online ad by AirBnB – it shows the popularity of yurts for tourist accommodation.  The R20,617 figure is for the monthly income.

Can you imagine yurt villages along all SA’s major routes, where travellers could stay for under R100 a night?  Now that would be an impetus for tourism!  And I’m sure many accommodation establishments will be taking a careful look at adding yurts to their offering.

Yurts have been around for over 2000 years and known to provide comfortable accommodation from -40°C to +40°C, withstanding winds of up to 160km/h.

My yurt was inspired by photos my sister sent from Mongolia and then, after further research, by the simplified yurt manufactured by Yurta in Canada.  The project is not a commercial venture but aimed to get people thinking out of the box.  I’d be happy to share what I’ve learnt with anyone who wants to take it further.

First, the traditional yurts which have been around for over two millennia right across Asia.

Traditional yurts in Mongolia (where they are called Gers — meaning “home”).  “Yurt” is a Russian word with the same meaning.

This traditional yurt shows how the bottom of the wall can be lifted to allow a draft to cool the interior.  You can see the number of wall laths used in a traditional yurt.

Then a Western take on a yurt by Canadian company Yurta — high-tech and dramatically simplified.  Using 30 laths for the walls appealed to me for its uncluttered look.

Yurta’s version of the traditional yurt.  Photo: Yurta

Yurta’s elegantly simple, 17-foot diameter (5.18 metres) shows off the frame and rafters as the wall covering is being added.  (That looks like the insulation.)  Photo: Yurta

So the yurting started!  Yurts are so well documented online that it’s just a matter of learning.  Any aspirant yurt builder must visit the Yurt Calculator.  It gives you everything you need to know, and even calculates the materials needed and gives the total cost.

For the record, my yurt is 6m in diameter with a floor area of 28.3m² and a total height of 2.95m.  It uses 16 rafters instead of normal 60, and the wall uses a similar lesser amount.  The height of the wall is 183cm,  The angle between the wall laths is 69 degrees.  This is the drawing the Yurt calculator produced to show the geometry of my structure:

A 6m diameter yurt is about the largest you can fit in the back of a standard bakkie.  Within my 6 metre yurt, I planned living, kitchen, bedroom and bathroom areas.  Would it work?  The proof is in the pudding, as they say — I was going to try yurt living for a few months to test it!  (Bathrooms in smaller yurts are not commonplace.)

The plan of my 6m yurt, showing living, kitchen, bedroom and bathroom areas.

What are the basic materials needed for my yurt’s structure?  Bear in mind that this was for a temporary yurt, to determine what sort of space it would offer…

A smaller yurt would be slightly cheaper and, if it’s just for short-term camping, you probably wouldn’t bother with the solid floor.  With a wall height of 1.83 metres, a strip of Ripcote needed to be added to the bottom of a 1.8 metre roll.  If the wall height was under 1.8 metres, this would incur a small saving in the material cost but a significant saving in the time to make up the covers.

Floor
The concept for the floor was 50mm of polystyrene to insulate the floor and raise it out of water’s way, to which hardboard would be glued.  The yurt’s Ripcote wall would then be drawn under the floor and tightened to provide a weatherproof seal.

Providing the ground is level and compacted, 50mm thick polystyrene sheets glued to 3.2mm thick Masonite actually provides a very nice floor!  After shopping around, Isolite provided the polystyrene.  They were fantastic to deal with and very knowledgeable.

They recommended Peekay for the adhesive.  This was a bit of a disaster.  The first adhesive they sold me “ate” the polystyrene — apparently it hadn’t been mixed properly when they decanted it from a big drum.  Thank goodness for doing a test first!

Plywood and thicker hardboards would have been ideal but cost and weight became an issue.  I wanted something I could erect on my own. Click & Lock flooring would also have been ideal, but cost (about R600/m²) was an issue for a temporary project.

To cut the circle, I looked for the right wire to attach to a solar battery but couldn’t find anyone to provide the correct advice.  Isolite offered to give me some wire but in the end I did the cutting with a kitchen knife heated over a blow torch.  That was more than adequate.

Frame
I approached the frame with trepidation — would it really work using 22x44mm SA Pine?  Would 30 pieces of wood really encompass a 6 metre diameter?  With proper planning, basic tools, and not too much skill, it’s possible to make the entire frame in a day.  And the Yurt Calculator proved to be absolutely spot on.

This is the entire yurt’s frame – the roof ring, the steel cable, the rafters and the complete wall.

I still marvel that the folded wall which is only 800mm wide, 44mm thick and 2220mm high extends to provide nearly 18 metres of wall, 1.83m high.

Erecting the yurt – the rafters are being bolted to the roof ring, which then gets raised with a lifter. Once the steel cable around the perimeter of the rafters is attached, the entire yurt is very, very sturdy.

Make up of covers
The make-up of the covers was sponsored by a leading tent manufacturer.  When it seemed that they would be unable to do it in the short term because of factory strikes and the year-end rush, I looked elsewhere.

An upholsterer with experience of manufacturing tents for Antarctic tourist bases seemed a good choice.  He quoted a first try at R5280 where the covers would be made up on the frame, which needed to be erected at his factory.  “This concept is new to us and we have learnt from past experience that many hidden costs usually pop up,” he said.  That was before he looked at the Yurt Calculator and it’s instructions for making up the covers.  He did say that subsequent covers would be cheaper — about R2500 – R3000 to make up — if the Ripcote was provided.

In the end, the covers were made up by the experienced tent manufacturer.  The entire yurt frame and the rolls of Ripcote were shipped upcountry and I provided the link  to the Yurt Calculator and it’s instructions for making up the covers.  I also sent a CAD drawing of efficient use of Ripcote with a hardboard template for cutting the roof panels. We had tried the template out with a test panel and it seemed fine.  They said it didn’t work but I think they preferred to adapt one of their existing tents.

Door

door

The door frame is SA Pine and the stable door is Shutterboard which has been treated in the traditional Japanese way — shou sugi ban (焼杉板)  — which makes it water-, bug- and fire-resistant.  It originated in the 18th Century primarily as way to treat cedar siding to make it weatherproof.  The technique — which involves charring a wood surface to render it a deep charcoal-black — has become popular recently as a treatment for contemporary exteriors and indoor furnishings alike.

The wood is charred using a blowtorch.  Excess charcoal is removed using a wire brush.  And then two coats of Linseed Oil are applied.  And the treated wood is said to be good for ten years when another application of Linseed Oil is due!

Kitchen counter/Services wall/Bathroom

A R20 plastic bowl from an Agri store makes the perfect, light-weight basin. Just cut a hole and fit a plugged outlet. It goes well the the luxury mixer tap.

What makes this yurt unique is the services wall which bisects half the yurt.  A kitchen counter hangs off the one side, with the toilet, hand basin and large shower on the other side.  It’s probably the most efficient plumbing solution possible.

Everything could be collapsed and light weight was a factor.  The kitchen basin is a R20 plastic basin from a hardware store.  The shower, which can be used as a bath, is a pond basin.

And it doesn’t need any underground services.  Blackwater from the Saniflo toilet goes to a biodigestor and greywater is pumped by another Saniflo unit to a recycling system.  Both these will be the subject of future stories.

It finally all comes together
When I contacted Jami & Peter Kastner at Stanford Hills Estate about testing the yurt there, they said they had just the spot — an idyllic grove which they had identified for camping.  And so the real adventure began.

There was a lot of enthusiastic and inquisitive farm help getting the yurt erected.  The first time I realised things were not going to be as expected was when someone said, “This comes together like an old army tent!”  Instead of the walls attaching to the steel cable around the yurt, according to the instructions, the walls attach to the roof with hooks.  Well, I thought, maybe with all their experience, the tentmaker has a better way of doing things…

The Yurt

The yurt hadn’t been up for more than a few days when a very outspoken businessman called. He had to see it NOW! He’d been wanting to buy a yurt from Mongolia for US$1800. I couldn’t dissuade him — it wasn’t anywhere near finished — and he arrived 10 minutes later.  Getting out of his vehicle, he looked at the yurt scornfully… “That’s not a yurt!  That’s a tent masquerading as a yurt,” he said.  “The roof is all wrong!”  A few moments later when he went inside, looking at the walls attached to the roof by hooks, he just shook his head.  Totally unimpressed, he left again as quickly as he had arrived, saying “The frame shows promise but the tentmaker is an idiot!”

And there I had a purist’s perspective!  The roof isn’t the smooth cover you’ll see in the pics at the top of the page, and the peaks and valleys between the rafters does encourage buffeting by wind.  It is reminiscent of an old Provincial Roads maintenance camp rondavel.  And the hooking of the walls to the roof — which doesn’t provide an airtight seal — was to become my biggest bugbear.

I had been warned that darker coloured canvas or Ripcote can be 40% hotter than lighter colours, so Cape Coaters supplied a roll of Ecru Ripcote — an off-white colour similar to the wall of the Yurta yurt at the top of the page.  This was lost at the at the factory where the covers were made up and they asked if they could make it with Sand Ripcote.  Yes, it is much hotter, even in winiter when the sun shines.  But insulating a yurt is quite easy.  The Mongolians use felt from their sheep, and so does Yurta in Canada, combining it with a space-age fabric.  A 100 metre roll of bubble wrap, costing about R240, does the job if one isn’t catering for extreme heat or cold.

Once you move inside, the interior of the yurt is a truly spectacular space.  And it is a space that works very well.

Yurt interior

More photos and stories to come… Coming next:

• The Catastrophe! …  and Making it all Work.
• What makes it unique?  A kitchen and bathroom with efficient greywater & blackwater recycling systems, only made possible by Saniflo’s ingenious products — the Sanicompact43 toilet and Sanivite greywater pump.  And its biodigester for R300!

You can subscribe to email notifications for future posts at the top of the right hand column alongside (on laptops & PCs). On low resolution mobile phones, you won’t see it.

The Jaguar I-Pace all-electric SUV is being launched in South Africa in April 2019

In the last quarter of 2018, the Tesla 3 electric vehicle (EV) was the best-selling medium luxury car in the USA.  This year, Forbes reported that Tesla Is On Track To Become America’s #1 Premium Automotive Company, Ahead Of BMW, Mercedes-Benz.

On Twitter, Tesla’s Elon Musk committed to Tesla stores opening in South Africa late in 2019.

The new Jaguar I-Pace launches in South Africa in April 2019.  It will be the first serious EV contender in SA with a range of almost 500 km, but a price of over R1.5 million.  In December 2018, the I-Pace was the best-selling car in the Netherlands, beating all other cars (not just EV) with sales of 2,621 units – notwithstanding the hefty price tag.  The Audi e-tron will be launched in South Africa in the middle of 2019.  Audi predict that by 2025 globally, one in three Audis will be electric.  Volkswagen have been testing their Golf replacement — the VW ID — in South Africa (see below) and that, along with the Toyota EV, should introduce EVs for the mass South African market from next year.

Walmart in the USA has announced that their stores will have EV charging facilities in 34 states by the end of 2019, providing customers with the facility to charge their EVs in the time it takes them to do their shopping.  They are installing 150kW — 350kW chargers at a cost of US$2 billion.  The Jaguar i-Pace only caters for a 100kW charger and, of all the manufacturers, only Porsche has committed to 350kW chargers for its new EV later in 2019. The VW EV caters for a 120kW charger.  Walmart says that a good EV charging experience is the key to retaining and gaining customers.

Will PicknPay, Woolworths, etc, demand EV charging stations from their landlords?

The Tesla Supercharger is a 480-volt DC fast-charging station. The Supercharger network was introduced in 2012 and, as of December 2018, their  network consisted of 11,414 individual Supercharger stalls at 1,375 locations worldwide.

Tesla supercharging stations charge with up to 135 kW of power distributed between two cars with a maximum of 120 kW per car. They take about 20 minutes to charge to 50%, 40 minutes to charge to 80%, and 75 minutes to 100% on the original 85 kWh Model S. The next version of Supercharging is expected to charge with more than 350 kW, and charging times will be slashed to 30% of current times.  (In Australia, charging stations of up to 450kW are on the cards.)

Will Tesla bring their supercharging stations to South Africa?  And where do we stand in South Africa now?

The Nissan Leaf and BMW i3 have been around for a few years and although the two companies announced collaboration on EV charging stations, there’s little to show for it.  In Cape Town, among the first charging stations were at the V&A Waterfront — always a few steps ahead — and Hotel Verde (as part of its green credentials).  Jaguar Land Rover has started rolling out its Powerway with 82 charging stations at a cost of R30 million, focusing on the major cities and major routes.

Audi South Africa will be introducing dedicated e-tron dealerships in major urban hubs, equipped with the 150 kWh super-fast chargers, with which the e-tron can be charged to 80% in around 30 minutes.

Don’t expect charging stations to proliferate at existing fuel service stations!  Who wants to spend an hour or even 15 minutes hanging around while your EV charges.  But you’ll be happy to spend the time at a restaurant or shopping or at a gym.  EV charging points are complementary to quality experiences or necessary chores.

Charging stations will become a feature along major routes… but what of the lesser routes?  I realised this while visiting Route 62 recently.  In the next few years, the N1 and N2 freeways will be catered for, and if Route 62 doesn’t do the same, it’s going to lose out badly.  This is an opportunity for Route 62 to entice the early adopters of EVs to become loyal customers.

How do you go about it and who will partner you?

Around 80% of SA’s charging stations currently being installed by Gridcars, who have been contracted by BMW, Jaguar Land Rover and others.  By April 2019, they will have charging stations every 100-150km along the N1 between Cape Town and Pretoria, N2 between Cape Town and Port Elizabeth, and N3 between Johannesburg and Durban.  Most will be 24-hour charging stations and have connected payment gateways.

Jaguar Powerway — – driving range in your new Jaguar EV.

These include 60kW DC fastchargers and SA will probably have to wait until Tesla and other major players enter the market before seeing superchargers and better.

So if your business wants to install a charger to attract business, what do you need to do?  Wait a few months seems to be the answer.  Companies like GridCars will probably start looking then for joint ventures after they finish the current roll out.  But if you don’t start planning now, you will be left out!

She had shown me a photo of the yurt belonging to the building manager for her apartment block before.  He and his family live in their ger or yurt alongside the apartment building.  But he had been away for his summer holidays and was re-erecting his ger on the same spot as last year.

The photo at 12:17pm shows the floor down and the frame erected.  By 1:58pm, the entire structure had been completed.

Yurts have provided accommodation across Asia as far as Turkey for thousands of years.  In Mongolia they are called gers, which means “home”.

Mongolia has an extreme climate — from as low as -40°C to as high as +40°C… and these gers provide a comfortable environment throughout that temperature range.

So… I just had to learn more about Yurts!  I’m not convinced that bricks or blocks & mortar are necessary the best building materials… and concrete is certainly not a green building material.  Apart from tourist and every day accommodation, are they a possible alternative to SA’s sprawling shanty towns?  When one starts reading about yurts, the passion and enthusiasm that people have for them stands out.

Yurts have become popular around the world and are “the most popular special accommodation type on Airbnb”, according to Airbnb, which declared “2014 as the Year of the Yurt”.

Mongolia’s capital experienced a boom after the Russians moved out and The Guardian wrote about Ulaanbataar’s Yurt Tent City:   “Public officials may struggle to coax the ger dwellers to swap their felt and canvas for bricks and mortar. Mongolians’ attachment to their gers is both practical – they are warm in winter and cool in summer – and emotional.”

But the yurts you’re likely to rent on AirBnB, or elsewhere in the West, will be a far cry from what you’ll find in Mongolia.  You can expect windows, a huge, opening rooflight and internal bathrooms.

Rose River Farm, Virginia, USA. A modern interpretation of a 100 sq metre yurt.

Here are some more conventional yurts, and this video also explains what makes them so special”

Or, for a high-tech, luxury yurt that remains true traditional yurt princles and is undeniably “green”, there’s Canadian yurt-maker, Yurta.

And a typical Mongolian ger…

Tourists can stay in one of these Mongolian yurts and experience farm life. The only thing that makes them a little less than authentic is the concrete base!

There is a yurt manufacturer in Cape Town, and a yurt you can stay in on the Van der Stel Pass between Villiersdorp and Bot River… and we hope to bring you more about that later.

Traditional yurts are made of canvas with a lining of wool felt.  The traditional structure is a latticework of thin poles or bamboo (as shown in the very first photo).  One North American yurt-builder used fire-resistant bubble wrap for insulation to preserve the translucence of the covering (cost R240 for a whole yurt!) and found it worked well for temperatures as low as -5°C.

What are their advantages?

• Portability.
• Insulation from cold and heat which beats bricks and mortar.
• A breathing structure, which makes it healthier.
• It’s the cheapest structure you can possibly build!
• Yurt owners have an emotional attachment to their yurts and there is a very active, global community of yurt owners.
• No building plans required!

Architectural Digest has described the yurt as “an architectural wonder of the world”.  This is because the shape of the yurt, in combination with its lightweight members being in both tension and compression, results in a structure that is highly efficient in maximizing strength and space, while also minimizing use of materials. This makes the yurt the ultimate mobile home.

In fact, this is the purpose for which the yurt was originally designed. Being permanent homes, they need to be structurally sound.  Being mobile, they also need to be easily dismantled and compactly packed-up so that they can be transported (usually on camels or yaks) and quickly reassembled at another site.  Remarkably, a traditional yurt could be completely rebuilt in about 2 hours.  The yurt’s original name is actually derived from a Turkic word referring to the imprint left in the ground by a moved yurt.

A yurt’s structural integrity is due to the combination of compression and tension working in conjunction to form a freestanding structure with a long roof span that lacks interior rafter supports – hence it is more spacious.  Compression and tension are achieved by the interplay between the yurt’s centre ring, rafters, and main cable. The rafters meet at the centre ring (or “compression ring”) located at the top and centre of the yurt. The ring holds the rafters in a state of compression, as the weight of the rafters produces inward and downward pressure. From the centre ring, the rafters radiate out and down at a thirty-degree angle toward the trellis wall at the yurt’s perimeter.  This creates a natural outward pressure against the wall. A cable or band (traditionally made of rope or woven cloth) at the top of the wall is preset to match the circumference of the perimeter wall in order to integrate the wall and roof structure and thereby hold the rafters in tension against the outward pressure.

The structural integrity of the yurt’s clever framework allows lightweight materials to be used for the roof, the walls, the dome and the door, all of which enclose and protect the yurt framework.

Come back to watch our adventures in building a yurt!

Cooking was done using gas and hot water was heated by a cheap solar water heater, supplemented by a hot water/space heater in winter using firewood.

Very early on, I wrote a story on the Ekanini iShacks outside Stellenbosch, where over 1,000 ‘shacks’ in an informal settlement had been converted to solar power.  I am in awe of that initiative.  Let’s make that mainstream.

“You can’t manage what you can’t measure”

I installed everything myself and have never done anything like this before.  My installation was, however, connected to the house’s electrical distribution board by the farm’s electrician, and used all the house’s existing electrical reticulation.

My first (very stupid) mistake was the connection to the solar panel.  After a few days, I discovered the single battery wasn’t charging.  So I bought a second battery while the first was being checked.  Buying a simple multimeter, I discovered my connection at the solar panel was the fault.  That multimeter proved its worth as my only measure for a long time.

At the suggestion of someone at Stellenbosch University’s Centre for Renewable & Sustainable Energy Studies, I obtained an Efergy (branded by Ellie’s in SA) Solar Hub.  After weeks of frustration and the worst customer support I’ve ever experienced, I discovered that it simply can’t measure 12 Volt power.  (I think they’ve rectified this but I haven’t had any response to emails.)

Then, rather late in the day, I discovered that my Victron Power Controller is compatible with their Bluetooth VE.Direct Smart dongle (R588), which plugs in the Controller and gives realtime information about the panels and batteries on my phone.  I wish I had this from Day One!

Panels
I don’t know how much difference there is between the various brands of premium panels but the one thing I have seen is the drop in panel prices since this project started.  The two 150W panels used up to know cost R1,710 each.  I can now buy GCL-P6  330W panels for R1,819, and Canadian Solar 355W panels for R2,090.  So prices have halved.

I did put some effort into maximising the power generated by allowing the panels to tilt according to the seasons.  That story is here.  It was evident from the start that getting through summers wasn’t going to be an issue, but winters would be a challenge,

Inverter
This converts 12 Volt DC electricity to 220 Volts AC. I  started off  using an old 300W inverter (bought for R500 in KZN to charge my laptop from my bakkie’s battery while staying at an off-the-grid lodge).  It worked well for lights, laptop, Wifi router and cellphone charging, but wasn’t sufficient for the fridge because of the power surge when the compressor turns on.  So an 800W inverter took its place pretty quickly.

“But you can’t use a modified sine wave inverter!” I had friends saying, “It will damage all your equipment.”  The TES inverter cost R1,140 and the alternative pure sine wave inverter suggested was a Victron Energy Inverter Phoenix Compact 12V 1200VA for R8,393.

There are no sensitive electronics in the fridge I have, and my laptop’s power is filtered by its charger, so I couldn’t foresee any problems.  And haven’t experienced any over the 2½ years.  It’s time to upgrade that inverter, both for more power and cleaner current to power, for example, a washing machine which does have a lot of sensitive electronics.

Without a hot water geyser and electric stove & oven, the actual power demand is not that high.

The total maximum demand — if all appliances are turned on at the same time — is only 120 Watts, excluding the power surges from some appliances.

• This system was never intended to cater for appliances like a large microwave, hair drier, vacuum cleaner, etc., which each use more than 1000W or even small electric heaters.
• Miscellaneous appliances such as toaster; small microwave; blender; etc. were used too rarely to be included in this table.  But they did work,
• A better inverter will use 60% less power than the one I used.

Batteries
I honestly believe that the only way anyone can justify buying a Tesla Powerwall is if they are a committed “early adopter” of new technology, and that the Powerwall is going to be a conversation piece in the living room.

Conventional lead acid batteries and hybrid batteries do as good a job, at a fraction of the price.  Long term investments in rapidly-changing technologies is a waste of money.  From 2022 — four years away — we will see a revolution in battery technologies with the introduction of solid state batteries, with higher charge densities and fast charging times.  Both Volkswagen and Toyota are committed to new electric vehicles using these batteries by then.

Nissan have opened a battery-recycling factory because they replace EV batteries when they reach 80% efficiency — the vehicle’s driving range is its most important feature.  They replace the dud cells with new ones and resell the battery packs for domestic use.  In Japan, a 24kWh battery pack costs 300,000 Yen (R42,000 at R0.14=JPY1).  A 24KwH Li-ion battery pack in SA will cost about R130,000.

What I have learned with the lead acid batteries I’ve been using is the importance of never running them flat and trying to always keep the charge above 50%.  Yes, you can use much more of the charge with lithium ion batteries, but you pay much more.  Battery weight and bulk is critical for mobile devices and electric vehicles, but not at all for houses.  The heavier the battery, the more difficult it is to steal.

I’ve also seen the importance of a proper enclosure for the batteries.  On cold winter mornings, the batteries lose a lot of capacity.  In the next phase of this project, the batteries will be supplied with some warmth on icy days.

The Laptop
The first thing I realised is that this is not a normal domestic test.  This house is used as an office and a home. An empty house would spend the day recharging the batteries for the night.

Habitually, I turn my laptop on when I wake up and turn it off when I go to sleep.  It can be on for 17 hours a day.  That was the first habit I changed.  Just closing it when I’m not using it — putting it into sleep mode — made a big difference in consumption.

Before I became laptop-conscious, I was using over 1000Wh a day — by far the biggest single appliance-user.  It can be equated to leaving a TV set on all day.

Apart from putting the laptop to sleep more often, changing the hard drive for a solid state disk, upgrading my phone and doing more on the new phone wasn’t only more convenient, it saved even more power.  And it’s great for watching movies!

Now if I had a Lenovo Carbon X1 laptop, with a battery life of up to 15 hours, that wouldn’t be a problem.  Its selling price of R40,400 is a problem!

The fridge
The fridge has its own story.  It’s a 150 litre Hisense with a rated consumption of 155kWh/year — that’s 425Wh/day or 18W/hour — very low by fridge standards  The reality is that the compressor motor turns on about three times an hour for several minutes, using a paltry 35W.  But… and it’s a very big but… I have seen very short spikes of 860W when the motor turns on.  At nighttime, that’s a battery killer… or, at best, the quickest way to shorten your battery’s life.

So, during winter when my power supply was stressed, I took a leaf from the book by Indian shopkeepers.  Being as parsimonious as they are, they habitually turn the mains switch off at night when they leave their shops to save electricity.  Of course, this turns all fridges off too.  So, in addition to the unreliability of Indian power supplies, this is why Asian fridge manufacturers were among the first to introduce emergency ratings — the number of hours a fridge stays cold without electricity.  Today, many freezers or fridges have 24 hour ratings.

Not so my Hisense… so I packed a big part of the freezer with refreezable ice bricks, since I rarely buy frozen products.  And that worked.  Turning the fridge off from 9pm to 9am in winter, it still managed to stay cold enough. Of course, you can’t do that if you have separate freezer and fridge sections.

There are inverter-friendly fridges on the SA market — where the compressor remains on all the time — but they all use more power than a top-end, standard fridge.

The best solution is also much more expensive.  A 260 litre A+++ Miele fridge/freezer (R29,000), for example, only uses 174kWh or 0.474kWh per day — not much more than the much smaller Hisense.  It’s power surge is minimal and the storage time if power is switched off is 24 hours.

Verdict for the end of the first winter:  150W of solar panels was just not enough to fully charge the two batteries.  There were several days when I had to take one battery away to be charged.  In a normal domestic situation where there is very little consumption during the day, and the panel just charges the batteries, this would not be a problem.

There were a few days when I used the bakkie’s battery to power the house — which didn’t shorten that battery’s life significantly.  (It did last 5 years and finally died when the buzzer reminding me that I’d left the headlights on stopped working!)  This does make the case for a mobile powerbank that can be remotely charged.

Cost of electricity: This assumes that the panels, controller and inverter have a life span of 20 years.  The batteries proved to have a lifespan of 18 months.  It’s a simple sum that doesn’t take into consideration interest charges.

Verdict for the end of the second winter:  I had bought an extra panel. There were only two days when I actually ran out of power, and the two panels were able to charge the battery quickly enough that I never had to resort to remote charging.

Cost of electricity: The single battery is still going strong 20 months after I bought it, although it is being used alongside two new batteries.  I assume its longevity is due to the fact that the extra panels meant it was discharged totally less often.  In the figures below, I’ve assumed that would have died after 24 months had it been on its own.

Verdict for the end of the third winter:  I bought two extra 102Ah lead acid batteries to supplement the existing one.  My battery usage rarely dropped below 50% (12.20V) and the discharge table from the battery manufacturer shows that these batteries should last about 3 years.  In spite of a very wet winter, I’ve never been able to get even close to exhausting the batteries.

Cost of electricity: Power security comes at a small cost, compared to the previous winter.  I wish I had rather bought Omnipower Hybrid batteries which would have seen costs much lower.

I will be testing the Omnipower Hybrid batteries next and they promise to offer far longer life, making them the most economical bet.

There has been about 2 hours on 2 days in different years when it was too dark for the panels to generate any electricity.  Many rainy days are still bright, and generate almost as much electricity as the sunniest days.  Dark weather very rarely lasts more than 36 hours.

Since this project started, I’ve generated 765kWh of my own electricity at the time of writing.  That feels very good! 

The next phase will generate up to 5.6kWh/day and be able to handle anything I can throw at it… far more the normal house scenario at a cost of R183/month (using the same methodology as above).  There will also be a ‘mobile Powerbank’ to provide added security during the worst of the winter months.  You’ll have to come back to read about that!

A note for Employers

I’ve been approached by scores and scores of farmworkers asking how they can go the solar route — like the community in Ekanini.  You can help them.

Municipalities get tied into loans/grants from Eskom to provide expensive township infrastructure, which ties them into even more expensive electricity.  The cost of the infrastructure doesn’t warrant the small amounts of electricity provided.

Maybe someone will tell me if the capital costs of PV panels, controllers and batteries can be written off against tax by employers?  Because a simple 12 Volt solar system would cost something like this:

In 2016, Stellenbosch Municipality was paying the Sustainability Institute R60 a month per household — the value of the free basic electricity subsidy for those connected to the Eskom grid.  All municipalities should be paying that amount for all solar-powered dwellings.

Do the sums, add interest charges, explore the tax benefits and harass your municipality for the free electricity subsidy…   This could be the biggest perk employers can give employees who live without electricity, or want to get off the Eskom system.  #LoyaltyRewards

Sun International’s GrandWest Casino and Entertainment World in Cape Town has announced the completion of a water purification plant on the property that will in future treat borehole water to potable standards.

The initiative began In February 2017 when the casino investigated feasible options to using potable water. They commissioned a water treatment plant on site that includes four groundwater wells and a treatment plant with iron removal, sand filtration, reverse osmosis and stripping capability to comfortably deliver up to 10 000 kilolitres per month. A Memorandum of Agreement was signed between GrandWest and the City of Cape Town to ensure that all water quality specifications and legal requirements were met.

The hospitality and entertainment industry were particularly hard hit by the effects of the unprecedented drought, but since implementing water-saving measures, GrandWest has used almost 50% less potable water.

GrandWest General Manager Mervyn Naidoo said: “To ensure business continuity, it was important to change our water supply mix and be less reliant on public resources. Thankfully our 2018 rainfall is higher than last year, however, the severity of the situation has taught us the importance of having access to alternative resources. Through our boreholes and water treatment plant we are joining the water-saving efforts of millions of Cape Town residents, the City and other businesses. By not drawing water from public reserves there is also substantially more for the residents of Cape Town. We are mindful, though, that underground water is not an unlimited resource and its management is critical. We intend to apply the same Level 6B restrictions to our borehole water as we did to municipally-supplied potable water.”

Aside from being able to guarantee drinking water for customers, there is also a financial case to be made for the plant. The cost of potable water is currently R50 per kilolitre (on the Level 6 commercial tariff associated with Level 6 water restrictions) compared with R9.20 per kilolitre from the treatment facility. It will take approximately 28 months for GrandWest to realise a return on its investment.

Explaining the process, GrandWest’s Engineering Manager Johan Gelderblom said: “The plant consists of four boreholes and water drawn from these is passed through a set of pre-filters that removes most of the metals and suspended solids. The filters are aerated to assist with oxidisation of the water and from there, it is stored in a holding or buffer tank. The water is then taken through a set of reverse osmosis RO filters from where it is finally pumped into a 400 000 litre holding tank. As required, the water is later pumped to the main water reservoir by means of a UV generator unit which stops bacteria and further purifies the water.”

“The borehole solution was built in phases. First we established the boreholes and tested the quality of the water. The appropriate purification process was then designed and, once City approval was obtained, the actual purification plant was built. The geohydrological measurements for the boreholes commenced in May 2017 and the plant produced its first purified water on 15 May 2018.”

Regular tests are conducted to ensure that the water quality complies with drinking water standards as laid down by the City.”

What else did GrandWest do?

• Bath plugs have been removed from all bathroom
• Water flow reducers have been fitted to shower heads
• Basins have been fitted with faucet aerators
• Bed linen and towels are only changed on request
• Non-essential back-of-house water faucets have been locked
• All water fountains on complex have been shut down;
• Urinal flushes are set to its lowest level
• Taps in the public facilities have been shut down (only one operational)
• Hand sanitisers have been implemented in public facilities
• Effluent treated greywater supply directly from the Municipal sewer treatment works, recycled water from The Ice Station, as well as non-potable water are used to water the gardens
• Many plant beds have been converted to water wise plant beds
• Boreholes drilled and the establishment of a water purification plant

At about $1,000 a m², they’re not cheap… but discount the cost of curtains, the ability to control your blinds with your mobile phone, and maybe you can justify them.  But you can be sure, if this catches on, prices will drop!

They generate up to 100W-150W of renewable energy per ±1m² of window, enough to power 30 LED light bulbs or three MacBooks.  So with ±4m² of window on the north-eastern face of the house, I would be able to generate 1.6-2.4kWh over four hours just on one side of the house.