Solar Hot Water … Don’t Make a Bomb!

I’ve done a lot of reading lately as I layout the plumbing for our home.

The funniest statement I read became the title of this post … let’s try not to kill ourselves while building our dream home!

Before I dive into the solar heated water I want to back up a bit … what I have been doing over the last few weeks is try to come up with a plumbing plan for this building.  This has proved far more complicated than I anticipated; I don’t have extensive experience in plumbing, and many of the systems going into this house are not typical.  Regardless, stuff happens and apparently it also flows down hill … how hard can it be?

The plumbing for this project includes:

  • Domestic water supply,
  • Grey water planters,
  • Septic system and associated plumbing,
  • Solar hot water heating,
  • Radiant floor heat

Domestic water supply

The domestic water supply for our house includes the following fixtures:

  1. kitchen (sink, dishwasher although we may not install one, we wanted to have the hook-ups)
  2. main bathroom (tub, sink, washing machine, toilet)
  3. ensuite bathroom (shower, sink, toilet)
  4. Hot Water (tank?)
Other than identifying the fixtures listed above I have not done a lot of thinking about the water supply yet …
A 1″ line enters our house at the back of the utility U and will probably run underground to the main bathroom before being distributed to the various fixtures listed above.

Grey water Planters

Here again not a lot of thought has gone into the final design of the planters.

We have chosen to set the highest point of the planters at the east edge of the building and slope them down to the west edge of the building.  This means the flow of grey water is set and we need to get all of the grey water from the plumbing fixtures to the east-most planter.  To accommodate this layout our bathrooms will probably be a step-up from the rest of the floor plan … this will (hopefully) give us the height we need to get the grey water to the east edge of the building.

The other choice was to set the lowest planter in the middle of the building and have the grey water run to this point from two directions … this seemed more complicated and frankly we did not plan for this early enough … the benefit of this layout would have been smaller elevation changes due to shorter travel distances (possibly no step-up into the bathrooms).

Septic System and Associated Plumbing

This is actually where I started thinking about the plumbing … unlike everything else in this building a septic system has well defined code requirements and is fairly straight forward to implement.

The waste pipe layout is complicated by the need to separate out the grey water flow from the flow from the black water fixtures and run it to the grey water planters.  In our layout the grey water flow will be valved; it will either flow to the grey water planters or out to the septic tank.  This means that we are compliant with the building code, and did not have to try and prove that we did not need a code compliant septic system for this building.  We had an existing septic tank and field on our site and to get a permit we just had to have a certified septic installer o.k. our system.

Solar Hot Water Heating

There are a lot of options to consider when using solar heat, and everybody seems to be pushing their design as the greatest thing since sliced bread.  Added to this, the BC Building code (I believe this is similar across Canada) places restrictions on what you can use … all of this makes specifying a system challenging.

For a good introduction on different solar options this article helped me.

I found the following questions (taken from the website that warns against making a solar bomb) to be helpful …

The Fundamental Questions

  • Does the proposed system operate at low temperatures? Solar collectors are not very efficient at temperatures of 180°F.
  • Has the need for storage of solar energy been considered?
  • How will excess heat be handled?
  • How will the need for freeze protection be handled?
  • What will happen if the electric power fails in the middle of the day?
  • What will happen when the power comes back on after a period of stagnation?
  • If something goes wrong, will the system fail to a safe condition
    (fail safe)?
  • How will the occupant know if the system is not working properly?

Keeping these questions in mind the first system that occurred to me was an open-loop system that relied on a thermosiphon to pump the water around.  Confused yet?  This compares to a closed-loop system with glycol (antifreeze) and an electrical pump.  Read on … it gets worse!

We have already identified the need to block at least the lower half of our bathroom windows … its a privacy thing.  It occurs to me that this window space could be ideal for solar collectors … I even picked out evacuated tube solar collectors … these babies would obscure the view without completely blocking the sunlight … sort of like frosted glass … only functional!

By placing these tubes inside the building envelope (using the window glass as a cover) we could eliminate the need for a closed glycol loop.  In fact, the system could be an open loop thermosiphon … eliminating glycol, a heat exchanger and the need for a pump … talk about elegant.  What is holding me back from embracing this design whole-heartedly is two considerations:
  1. Will the lines close to the glass risk freezing at night, or if the building is un-occupied for an extended period of time?  Our building interior has not dropped below freezing in the two years it has been standing, but we have seen frost build up on the windows … a pipe close to the windows may risk freezing.
  2. Will the system generate a lot of undesirable waste heat in the building envelope during the summer months?

I am still tossing this idea around … variations on it are used in warmer climates.

With those considerations in mind the system that is currently winning is shown in the following image.

The solar panels are on the roof so it is a close-looped system and would use an anti-freeze solution in the heat exchange loop.  The necessity for an electric pump is eliminated by using a bubble pump … a solar pump that pumps when the sun is out by establishing a thermosiphon loop.  This pump is passive in that it works when the collectors are heated by the sun and shuts down when the sun is gone … which is pretty much when you want to pump … eliminating the need for an electric pump and a controller.

The hot water tank is used for storing the solar heat.  The tank could have an electric backup element or be propane … meaning that you will always have hot water … I still have not figured out which is the better option.

Radiant Floor Heat

We plan to have radiant floor heat in the high-use floor spaces of the earthship.  My intention is to use the solar heated water for the heating loops.

I am still trying to work this out but will look something like:

This means that the hydronic heating loops will not be passive, an electric pump will be used to move the water.  I have read about using a thermosiphon loop for this, but they still had a backup pump in case bubbles blocked the thermosiphon … so I do not think making this an active loop is a bad idea.  Our intention is to use a wood gasifier to produce electricity … the gasifier will also generate a lot of heat and I see it being primarily responsible for providing heat for the radiant floor system.  I have not shown it in this diagram because I am still wrapping my head around how it will be implemented.

Still a lot more to figure out here but this is a start.

I am curious what other people have done or come up with …

I will try to keep posting my design as it evolves … I am currently overwhelmed by the slope of this task and writing about it helps to clarify my thoughts.

Back in business

On Thursday evening we finally got the van running again.  We put the engine back in and carefully retraced the steps that we had religiously recorded while removing the engine.  When we were ready to try and turn the engine over, I took one last look under the hood and saw an electrical connection that hadn’t been rejoined.  With only the cosmetic front still unassembled (why put it back on if we had to take it off again, says I, the optimist), Chris turned the key and it started like it was the old engine.  On first try. With no hiccuping or grinding or nasty smells.

I admit I literally jumped in the air and made victory signs with both hands.  It was such an intense 10 days from when we seized the engine, that it was hard to believe we’d actually fixed it. Chris, the eternal engineer, is amused by this thought.  But there you go.

Chris and Stephen’s trip to California had been in the plans for almost a month.  Chris was going to a weekend workshop at All Power Labs, the company he bought the gasifier kit from in January and he was very much looking forward to it. He’d spent several hours talking to and learning from the folks at All Power when we were there last, and I think they were looking forward to seeing him, too. Chris has been blogging about putting together the gasifier and I think there were a few of the 70 participants (worldwide) who were hoping to talk to him before possibly purchasing a kit of their own.  When we realized that a week or more away from home wasn’t in the cards for me, we immediately gave my ticket to Stephen and this trip to Berkley was also going to be a dad-son trip for him and Chris.

That ended roadside 0n Hwy 5 just five kilometres from our drivway on March 27th. The girls and I had gone on ahead in the pick up truck. We were all headed to Kamloops to see The Hunger Games with our homeschool group and the boys were going to carry on to California after the movie ended later that evening.

A once-in-a-lifetime oversight by Chris during an oil change left the old filter ring hanging in the assembly. Chris attached the new filter and ring on top, making an imperfect seal; a problem, however, that wasn’t detectable at idle when he tested the van for oil leaks right after changing the filter.  Highway speed increased the pressure in the system and blew the seal and all the oil out of the engine. It took only minutes to seize the engine.

I think I got over the shock of this about 5 min after arriving back in Darfield after Stephen called me to tell me they were “broken down by the side of the road”.  I’m very much a don’t-cry-over-spilled-milk kind of person and see no value in stomping my feet and cursing and generally making myself feel crappier than I need to. I think once Chris realized I was taking it in stride, he managed to accept the fact that really, mistakes do happen and he was able to move on quickly as well.

We had several options.  One of the first comments made by another Delica owner on the Delica forums we post to (and Chris posted about what happened to get some advice and direction) was “mothball the van and buy another”!  This was not an option for us as we had invested a fair bit in the conversion to waste vegetable oil and couldn’t see the math working under this scenario. Our other options were not whether we would replace the engine, but if we were going to do it ourselves or pay somebody else to do it.

We spent a day calling every Delica dealer in BC to find out if anybody had a used engine, what it cost, and how many kilometres were on it. We got a range of prices:  $3200 for an engine with 167,000 kms and $2,300 for one with $115,000.  We explored how much it would cost to tow the van to a shop close to where we might buy the engine, and how much the labour would be to replace it.

Our local shop estimated roughly $2000 in labour, mostly because they wouldn’t have worked on an import vehicle like this before.  We loved the folks on the Island; they were efficient, knowledgable and responsive. However, the total bill to get the van over there and have them put the engine in would have been over $5000.  Just getting the engine back here would have been very expensive.  We looked at joining BCAA Premier, waiting the requisite 48 hours, and having the van towed to Richmond.  There would be 320km free towing for the $162 membership, but we would have had to have picked up the additional 80 kms at $2.25 per km.

In the end we decided to buy the $2300 engine from Amazing Auto Sales in Richmond. We decided that basedon some really fantastic shop manuals available on the internet, that we were capable of doing the engine job ourselves.  Mardy, at Amazing Auto Sales, did offer to remove our seized engine and replace it with the new one, for about $900 in labour. An extraordinarily good price. And, he has seven years experience working on these vans. In fact, the shop he would have sent it to was CVI, and we had heard amazing things about this shop, as well.

We decided to remove the engine ourselves and take it to Mardy. Included in the cost of the engine Mardy offered to swap the injector pumps (our van is automatic and the pump on his was manual). There were also some other small pieces to swap.

Chris and Stephen began pulling the engine on the 30th, and Chris made copious notes (which are posted on this blog). When I was not working in Kamloops I helped Chris.  My dad had an engine hoist and this was invaluable both for pulling and putting it back in. In fact, I think it would have simply been impossible for us to do this job without one.  We had the tow truck park the van behind our shop as it would have been pretty difficult to get it into the shop. The natural light made for good pictures (see previous posts) but left us open to the weather, some rain and snow. All in all it took three 8-hour days to take the engine out. I would attribute one day to recording notes.  Late on April 1 we swung the engine into the pick-up truck and made plans to leave the next morning.

We left Darfield at 4:30 am on April 2nd and arrived in Richmond at 10:30.  We loaded the new/used engine in the back of our pickup behind the seized engine end Mardy sent us to CVI to have their awesome mechanic spend 1.5 hours swapping parts. We elected to change the seal on the injector pump at the same time. We’d never get another chance to get at it so easily!

The foks at CVI were great and the mechanic didn’t seem too perturbed to have Chris and I hang out at the pickup while he swapped parts from one to the other. My attempts to start conversations didn’t go too far; the mechanic was fast and focused.

We headed back to Mardy’s shop and he borrowed a small forklift from a neighbour and we unloaded our seized engine.  Mardy is going to try to sell parts off it as a way to recoup some more dollars.

Mardy came to Canada from Japan at the age of 28.  If I understood correctly he was a shop supervisor for a crew that was working on the SkyTrain.  He got involved in importing vehicles to Canada from Japan after that.  I must admit that before we met him in person I wasn’t sure what our experience would be like. I found it difficult to understand him on the phone (but I never do well with any kind of accent; it’s embarrassing for me, actually).  I also think that cultural differences are difficult to appreciate until you are face to face with somebody.  I found Mardy to be genuine, eager to help and quick to give advice from his years of knowledge.  Since we picked up the engine, he’s given us information on how to cross reference the brake caliper part at our local parts shop.

At about 3:00 pm we’d strapped down the engine and headed back home. We elected to travel the Fraser Canyon route and the trip down and back was gorgeous.  Well, for me it was. As Chris started to pull the engine four days earlier, he came down with a nasty head cold.

This head cold persisted through re-assembly, which I was able to put two entire days toward.  It took two days to re-assemble (we were only reading our notes, not making them).  We even replaced the fuel filter, again because it was easier to get at partially assembled. We managed to get into only a few minor snarking events and the marriage is still intact.

Day 3 of re-assembly was the cosmetic parts for the front, and a look at a few things that had been waiting for attention. Namely the air conditioning (which we weren’t sure was actually air conditioning or a fan motor issue). I wanted to look at some of the interior light bulbs and give the sliding door mechanism a good grease.  We did test the WVO system and initially it didn’t work. Chris quickly tracked down a blown fuse and this was replaced.

I’ve been driving the van for the last few days and obsessively checking the motor oil (hey, who can blame me? I’m sure it will wear off).  I’ve been testing the van on WVO in different situations and we have not had a single stalling issue, in any situation whatsoever.  We had speculated that our stalling issues might improve as the weather got warmer.  I wonder (although Chris poo poos this) if it isn’t the new engine. I have to take my silver linings where I can invent them.

Chris is still recovering from his head cold, which I’ve been wondering might have been something more serious.  Because this was such a major project, we are now only catching up on jobs we had set aside. I had many things I was going to do when Chris was gone and I’m now just wrapping my head around them.  What was to be a holiday for Chris, was anything but, so he hasn’t had the restorative benefits of that.  The kids managed to keep up with the basics of school, but we are now trying to pick things up a bit with that. It was going to be right around now that Chris and I were going to talk about the earthship and form some sort of plan.  I suspect that will wait another few days until we both recover.

I’m not really whining.  We did well.  Five days of actual mechanic-ing and $2700 taxes included got us back on the road again. That’s stellar if I do say so!

 

Wood Gasifier … still building

Over the last 3 days I have been building here and there when I have had time …

I did get a response back from Julia Hasty at All Power Labs answering my questions raised in the last post.  I have added her response to these questions as a comment to that post … thanks Julia!  In the interim I decided to leave the parts I had questions with and carry on.

The first thing I did was to weld the three assemblies (ash port, grate shake port and gas out)to the gas cowling.  This work seemed to go well, and after I was done I set aside the gas cowling.

I then started working on the reactor … first thing I did was to watch the video from All Power Labs about fabricating the reactor.   This is a long video and I am guessing that welding the reactor together is
probably the biggest job in this project … I’ll know if I was right when I am done!  I started by tack welding the middle top and bottom flanges.  This step was similar to work done previously … I worked to make sure that the flanges and the sheet metal sides fit together as tightly as possible … lots of clamping.

In the video you are warned to use small tack welds on the underside of the top flange … I obviously did not appreciate how small these tack welds needed to be!  I ended up having to grind all but one of these tacks back to accommodate the air neck … listen to the video and use small tack welds for the top flange!

Once the three flanges were tacked all of the seams were welded air tight except for the top flange.  I found welding the gas line connectors to the mid flange a little challenging … they are to be welded air tight but there is not a lot of space for the welding gun between a connector and the reactor wall.  I found my technique improved with each connector.

After the connectors the air neck was tacked into place.  The video seems to be out of synch with the

actual parts provided at this point … the video shows two smaller holes in the air neck being lined up with matching holes in the reactor wall with matching 1″ pipes welded (air tight) into these holes.  The holes are not identical … one set of holes is as shown and the other set is for a pipe inserted on a 45 degree angle.  I did not have the 1″ pipes shown in the video … I used the provided threaded nipples (one of these was cut on a 45 degree angle).  The different parts that I used seemed to be the only obvious choice in this case.  The seams of the air neck were welded air tight.  The seem between the wall, bottom of the upper flange and the air neck was tough … you need to weld all three surfaces and getting good heat penetration on the wall was tough … again the gun nozzle was big for the small space … I am least happy with this weld but I think I got it to work.  A 1″ weld coupling was then welded air tight to the air neck.

I then welded the 1/2″ 90 degree elbows into the larger holes in the bottom flange.  The directions in the

video worked well.  I scribed my straight lines up the inside walls of the reactor from the centre line of these holes by using a plumb bob … I was not sure how else to do it.  I did not enjoy welding in the space under the end of the elbow that was raised 1/8″ above the surface of the flange; it was a lot of welding, I think my gap between the elbow and the flange surface was a little too big and I am sure better technique would have helped!  I experienced a lot of spatter while filling in and I thing I got a drop of weld on my laptop screen … no serious damage but the laptop will now be farther from my work area!  It has been really useful to refer to the videos while working … but probably not worth the laptop.

I then was going to start work on the hourglass hearth.  I started by tracking down parts, but after about an hour of looking (trying to be thorough) I was unable to find the hearth base flange.  I ended up watching all of the remaining fabrication videos at this point so that I could match parts to assembled components, and I still could not find a part that looked like the hearth base flange.  It also looks like I may be missing the grate support ledge lollipop (I want to check again tomorrow about this part as I was really trying to track down the hearth flange while watching this video.

I am impressed so far with this kit; the videos are well explained and the cut parts have fitted together well.  I think I have done most of the welding at this point and am starting to think about painting.

Questions to this point that I need to resolve:

  1. The holes in the air neck that match up to holes in the reactor walls are not as shown in the video.  The pipes that go into these holes are also not as shown.  I am assuming that two threaded nipples are used here instead (one of them cut at 45 degrees)?
  2. Has the base flange for the hourglass hearth changed in appearance since the last video?  I do not think it has but what do I do if I think it is missing?
  3. The other thing I realized watching the rest of the videos is I will be welding some stainless parts.  I have not welded stainless before; I know you want to be well ventilated as the fumes are nasty, and I think you need special wire for stainless.  I am going to read about differences welding stainless as opposed to welding typical steel.  What do I need to be thinking about?

    I finished off the day today by welding the brake line seams of the rocket legs.  These legs seemed quite strong to me even without welding the seems, but regardless it is now done.