The Heating and Air Conditioning system (HVAC)

Integral Design Group used their expertise and experience in the designing of this unique system.  The HVAC is designed to take fresh air and return air through a number of 4” diameter pipes called earth tubes.  In the process the air takes on the temperature of the ground.  According to studies the earth tubes an have change the temperature by up to 13 degree Celsius.   In the building world there is lots of discussion about this use of this passive technology.  The long and short if it is, it works.

“We love the earth tube system installed in our home” Chris and Cathy Jennens, Kelowna, BC

In this house we will be running all of the air supply to the house fan through these tubes.  Manually adjusted dampers will mix the approbate amounts of fresh air into the system.  These dampers will be adjusted in the spring and fall.

Many materials for the earth tubes were considered.  (More detailed discussion can be found here ) Concrete, steel, HDPE, PVC, and polyethylene, .  Concrete works well for larger projects but is expensive and laborious to install without the use of heavy machinery.  Steel when coated offered an attractive alternative, however it’s proximity to water table and cost of install put questions in our mind about longevity and ruled it out of this project.  HDPE is available in many sizes including the 18” diameter we required, but the costs of the piping and heat welding required to connect the joints was expensive.   PVC is toxic and not permitted on LBC projects. That left us with polyethylene or “big O” as it’s referred to.  This piping is inexpensive, flexible, but only comes in 4” diameters.  Our challenge now is to bury the 18 4” pipes, each 100’ long, into the space beside the Ethel Lane House.

 

Fresh energy

Returning from Living Future in Portland we have once again found new purpose.  There are so many cool people doing amazing things.  Looking forward to connecting with everyone again next year at LF15 in Seattle. But we trust that there will be many more opportunities to connect, like Groundswell and Collaborative Summit in September.

 

Earth Tubes

With the help of Trevor Butler and his company Earth Tubes we will be installing buried earth tubes in Ethel Lane House similar to the ones in the picture.  Over the centuries this “technology” has been used around the world but only recently have designers and engineers begun to revisit these systems.

Our goal is to install the equivalent of 12” diameter duct into a trench around the perimeter of the building.  This trench will simply act as a method of cooling the fresh air supply in the summer or warming it up in the winter.  We will be using 100” of polyethylene Big “O” similar to the material used in perimeter drains.

Earth Tube Diagram
From David Suzuki Earth Tubes also may be referred to as air-ground heat exchanger, earth warming/cooling tubes, earth channels, earth air tunnels, underground air pipes. http://www.suzukipublicschool.ca/

Moving Water Systems

As noted in our last post we have had to do away with a full house craw space.  Instead we have opted for a hybrid of sorts.  We will digging a dropped crawlspace under the the bathroom to accommodate the composting toilet.  This space will hold the systems for the Black, Grey and fresh water supply.  All pumps and systems that can be damaged by water must be installed above the high water mark, which is only a couple of feet down from the ceiling.   Our composting toilet has no electrical or mechanical systems that will be damaged by water, and our backup sump pump is submersible.

We have also moved the rain water tanks out of the crawlspace to a hole to be dug under the deck.  This will eliminate the chance of hydraulic lifting that might happen in flood situations.  Our choice of tanks has also changed and we will be installing only one Super Tank from Premier plastics that will be buried below grade close to spring ground water levels, which are rumoured to be 8’ below ground in that area.

 

Water Storage Systems

Lots of discussion this week around Water Storage systems.  We explored a number of options for storage but ultimately ended up deciding on installing Polyethylene tanks into basement.

Options considered were Made in BC, and NSF Food Grade

Polyethylene

Pro: Good volume per sqf of floor, Moderately Priced, Easy to clean,

Con: Must be tethered to foundation so it doesn’t lift building (in flood)

Concrete tanks (built in place)

Pro: Highest volume per sqf, best integration into building

Con: Expensive, difficult to build proper lid, would require proper engineering, waterproof concrete additives expensive, High water table added a lot of engineering, material and labour costs,

Concrete Tanks (pre-formed)

Pro: Simple to install

Con: Expensive

Bladder Tanks

Pro: Inexpensive, Flexible, no need for tethering (due to high water table), inexpensive shipping

Con: harder to clean, Least volume per sqf

Polyethylene tank

 

Passive House

Passive house wall exampleMeeting with colleges of ours to discuss the process of making this project a passive house.  There are a lot of really interesting approaches to building a super efficient building envelop.   Systems like:

  • Double stud walls
  • Rigid insulation over standard stud wall
  • Double stud walls + vapour barrier + interior plumbing electrical wall

All of these systems result in a wall that is at least 1’ thick.

(Reminds me of the Log Houses my Uncle built in the 1980s with the deep window ledges and reading nooks looking out side.)

The system we are leaning towards is the double stud wall system.  Simple, less expensive but harder to air seal. We will implement an Airtight drywall approach to sealing this building (using drywall and paint to create the vapour barrier).

Generous Consideration

A huge opportunity has opened its self up.  The city has agreed to postpone a portion of the Development cost that would upgrade the water main supply from 13mm to 19mm.  Typically projects like this are required to upgrade the water service because of additional fixtures. What we will attempt to prove is that the rainwater collection systems we have planned, combined with the single occupant of the house will mean minimal increase in water usage for the new building.  This opportunity does NOT mean that we have avoided paying the development charges.  What it means is that they have allowed us to delay the expense of the water supply upgrade until renovations/additions are carried out on the existing house.  We should also point out that this opportunity is a one off and we expect that this generous exception will not happen again.

So the rain water system is looking promising once more.  We are considering a redesign of the storage tanks right now and may opt for builtin concrete tank, instead of food grade plastic tanks.  But the system as planned will be collecting rain water into a 9m3 tank (2500 gallons).  This will be cleaned and filtered to near potable standards (including but not limited to 5 micron filter + UV + Black Carbon filter) before it is distributed to the Laundry, toilet (should we need it), and outside irrigation system.  There is some debate about using this light grey water is appropriate in the dish washer.

The City will require their water to feed the kitchen sink, bathroom sink. Laundry sink and shower.

Looking forward to seeing how this project will develop.

 

Finding the right Supply

A productive visit with staff at Cascadia offices in both Portland and Seattle early January.  A long discussion about material supply chains and the Materials petal.  The major push is to ensure that we are using FSC lumber up here.  This is interesting because to date projects in BC, Canada have not used 100% FSC. Exceptions have been made for “Pine Beetle Kill that would have been Clear cut anyway.”  At the SFU childcare Centre  Kourosh Mahvash came up with a fascinating solution that basically involved purchasing a forest and processing the beetle kill wood with the help of a local mill.

Returning to Kelowna we connected with the Manager for Forest and Environment at Tolko, one of the local mills.  Turns out we connected to the person that had procured Pine Beetle Kill Wood for the building in Penticton.  Further discussion around sustainability and certification outlined for us the complexities of wood supply in BC and Canada.   This aspect of the LBC has many facets and angles to be considered.

At this point our strategy is to connect to Local wood, cut by Local people, milled at plants 120 km from Kelowna.  Long discussion and consideration was given to using all FSC lumber.  It is not making sense both ethically and financially to drive across the boarder to the US to purchase lumber and plywood.  Let us hope that the LBC review board sees it the way we do.

 

Reality Check

Well just got off the phone with a lady from the Living Building Challenge and we are not feeling quite as optimistic as we once were.  Some huge challenges that we need to address are:

  • All black water (poo and pee) must be processed on site.  That is problem because in Kelowna it is usually not allowed to process black water onsite in residential neighbourhoods.
  • Requirement for FSC certified wood is also going to be an expensive option here in BC.  We may need to do things differently.
  • Providing enough electricity.  This is not difficult it just means more solar panels on the roof.  Thankfully global demand has been reducing the costs of this energy source year after year.

 

Looking closely at Materials

Last week we attended a conference in Bellingham and met a lot of interesting people building interesting things.  Of note was a fascinating discussion about the Red List presented by one of the architects from the group that designed the Bullit Center in Seattle.  The processes established to complete the material “vetting” was impressive.  One person was dedicated to the cause full time for a number of months in order to complete the tasks.  On our Carriage house we intend to keep the material selection to a minimum and thus dramatically reduce the time and energy required to complete the “vetting” process.

Of other notes from the conference was a fantastic presentation from the owner of Small Works, a Vancouver based Laneway Housing builder.  His ideas around small, efficient, prefabricated, Dwellings was inspiring.  We look forward to working with them.