Tubes!

The tubes are conduit runs through the foundation.  This is a photo of the concrete forms.  Concrete will be poured into the forms to create the foundation walls.  The tubes provide a chase for things to be run up into the unit – wires, pipes, etc.

Seems like a lot of tubes, right?  We have a lot going on in these units – regular stuff like water pipes and electricity, but in our case ground source piping, extra wires for the solar panels…and who knows what else?  So we have a lot of tubes.

Drilling the first well

Ground source heat pumps in homes are used for heating both hot water and the home interior. Generally, they are a water based system – they heat water, rather than air, like your typical forced air furnace.

Ground source heat pumps essentially combine two very efficient technologies to result in an extremely efficient technology. They include two parts: a ground well system for preheating the fluid to the average ground temperature (in Issaquah, 50 degrees or so). Once the fluid has run through the ground well field and been prewarmed, it is then run through the heat pump, which then heats it further up to 125 degrees or thereabouts.

The radical thing about using the preheating loop is that effectively, the heat pump only has to heat from the 50 degree baseline, year round. That means that in the dead of winter, when it’s 30 degrees outside, the heating system is effectively only having to heat from 50 degrees, since it’s using the well field water. The heat pump has its own cool efficiency which I’ll explain another time.

So, back to our well field. To create our well field, our mechanical engineer (Stantec in Seattle) determined the appropriate sizing based on the total heating load for our ten units. They determined we needed 3,000 feet of vertical wells. Our initial design configured that 3,000 feet into ten 300 foot deep wells connected by a set of pipes (called a manifold) just under the surface.

Into each well, a very heavy duty double U shaped one inch diameter pipe is run down the bore hole. The pipe is made out of polyethylene, and is the same pipe used to carry natural gas to homes. The pipe is then grouted in place with a material called bentonite, which is a sort of flexible inert concrete. The grouting ensures that the pipe and the fluid inside the pipe is in full contact with the surrounding ground, to maximize the thermal conductivity.

The problem we’ve run into is that we’ve had some issues boring holes that deep. Portions of Issaquah Highlands are an old lateral moraine from the big Puget Sound glaciations of the last Ice Age. There are lenses of gravel which tend to collapse when we’ve drilled through them. In particular, there is a lens at around 200 feet.  As a result, we’ve had to modify our well field, and increase the number of wells to fifteen or thereabouts. It’s added cost and taken more time.

I was in the field yesterday watching them place one of the pipes and grout it in place. It is tough work for the drillers – sledgehammers, rubber boots, hard hats, a big drill rig and a lot of sweat. It was a very good reminder to me that this is where the rubber hits the road. After years of planning, evaluating the options, and weighing the pro’s and con’s, here was a crew of three guys working hard all day, drilling a hole, muscling a tube down the hole, mixing a big batch of grout, pumping it down the hole, and moving on to the next one. When zHome is done it will be a mix of brains and guts and stamina.

This home, which will be the Shirey’s personal residence, is exactly what it says it is – it provides ideas to the building and home buying audiences for advanced energy saving technologies which are part of a potential zero energy strategy.  It includes such advanced technologies as structural insulated panels, (R-24 walls, R-40 roof), solar hot water heating, LED lighting, a reverse chiller for heating, a helical wind turbine, and a 2.5 kwh photovoltaic panel array.  The combination of all these technologies will most certainly help the house get much of the way to zero net energy usage – resulting in one of the most advanced homes built regionally to date from an energy standpoint.  The WSU Energy Program projects the home will have net energy bills of about $500 a year, quite an achievement.  I suspect given how green the Shirey’s are, they are likely to do even better than this in actual usage.

Installing the structural insulated panels

As wholistic green builders, the Shireys have also included a number of other cutting edge green components.  Extensive green roofs and native landscaping will help reduce the roof rainwater runoff.  A 3,000 gallon rainwater cistern provides irrigation.  Lots of neat green materials, like FSC floors, recycled plate glass counters, and concrete countertops show green homes can be incredibly beautiful.

I have had the pleasure of knowing the Shireys for a number of years.  They own and run Shirey Contracting, located here in Issaquah, WA.  They are true green building pioneers, and were some of the first builders regionally to draw the important connection between building and sustainability.  They have been builders for several decades and were early users of structural insulated panels, which can result in tight, energy efficient walls and quick construction timelines.  Donna was instrumental in starting Built Green, the green building program for King and Snohomish Counties.  In addition to the Idea House, the Shireys are also building a home in Florida which will be LEED platinum – two truly cutting edge homes.

A great 13 minute educational video of the home was made by King County GreenTools – don’t miss it.  Also, the Zero Energy Idea House will be open Saturdays and Sundays from 10 a.m. to 4 p.m. through Nov. 8 for self guided tours.  It is most definitely worth checking out – it is a truly inspiring home.

Hockerton Housing Project

Another amazing zero energy project in England is the Hockerton Housing Project.  This project was built in the 1990s by five pioneering families, who wanted to radically reduce their environmental impacts.

I visited Hockerton in 2005 during my same trip as my BedZED visit.  Hockerton is way up north by Southwell, in the Midlands.  Incidentally, Southwell has a gorgeous Romanesque cathedral, promoted to cathedral status just at the end of the 1800s.

Southwell Cathedral

Even though zHome and Hockerton share the same core paradigm of low impact living, they go about it in completely different ways.  Hockerton is completely passively heated – relying on solar energy completely.  A solar atrium in the front of the homes heats during the course of the day, and this heat radiates back into the homes.  The main part of the homes is super insulated, and then covered with earth.  The earth acts as a heat sink, retaining heat energy over the course of the summer, and then radiating that heat back into the homes over the winter.   The result is interior temperatures which rise and fall on a sine wave, peaking at 75 degrees at the end of the summer and dropping to 62 degrees at the end of winter.

This is just a quick snapshot of the project, please see their great website for more information.

BedZED – solar atrium elevation

BedZed sits like an island in the south London suburb of Beddington (BedZED stands for Beddington Zero Energy Development).  The day I visited it, I did the long walk from the local train station, along a fairly busy, not very attractive arterial.  Suddenly, there it was – a sort of Earthbound naturalistic UFO set amidst the dreary backdrop of run of the mill flats and commercial buildings.

BedZED is mixed housing/office development, with about 100 townhome units and about 13,000 square feet of offices.  But that benign, run of the mill description doesn’t really give you any sense of it.  My visit to BedZED is perhaps the single most hopeful day in my life, environmentally speaking (except for my visit to Hockerton – more on that later).  BedZED is one of a handful of buildings planet-wide that has what is at least close to a truly sustainable footprint.  Like zHome, BedZED established a number of environmental benchmarks, shown below, along with how well they’ve actually performed (the community was completed in 2002). What BedZED shows us is that radically more sustainable buildings are possible, and within reach now, not some indeterminate time in the future.  Here is a chart of the environmental specifications for the project, along with how it’s actually performed:

The energy component of BedZED is what I think is most compelling, and I am really taken with the technologies they used.  What is most interesting to me is that many of them are completely different from zHome, even though the climates are quite similar.  This gives me a lot of hope because it says there are a lot of technological pathways to achieve zero net energy/carbon buildings.

BedZED starts with the same hyper-insulated wall section that zHome does – that seems like a basic constant in our climate.  But BedZED uses masonry (brick and concrete) walls – typical of European residential construction – rather than wood stick frame.  BedZED has also wholeheartedly embraced passive solar heating of the homes, with a solar atrium sitting on the south side of the homes, unlike zHome.  This solar atrium has glass with a high solar heat gain character, allowing it to heat up dramatically. Once this atrium has warmed up toward the end of the day, the residents open an inner set of highly insulated triple paned French doors to allow the heat into the units. This solar heating provides the majority of the required heating for the units. Hot water, and supplemental water based hydronic heating, is provided by means of a combined heat and power unit for the whole project. This is essentially a large boiler with a turbine attached to generate electricity. This system was designed to run off wood waste, but when I was there it was running off of natural gas. The passive solar heating system heats the homes well enough to only need one heating element in the homes: a heated towel rack!

Combined heat and power building

Where are your priorities? Heated towel bar

My favorite view of BedZED is across the soccer pitch, with BedZED, and a neighboring project which was built at the same time, in view next to each other. The BedZED architects (Bill Dunster Architects) nicknamed the neighbor BedHED, for Beddington High Energy Development. It’s a pretty amazing image – two projects, built at the same time, with the same essential building structure and technology, but one which uses radically less resource and emits radically less CO2. Smart, thoughtful design, coupled with innovative technologies got them there – Yes they did – and Yes we can! (Forgive me, I couldn’t help myself, it’s Inauguration Day tomorrow).

BedZED and BedHED

Here is a link to the official BedZED website.

Sensible House

I have come to believe that innovation rarely occurs in a vacuum, with a mad scientist coming up with something that noone else could see or envision.  Even with radical jumps in design, there are prototypes, predecessors, and context.  We all stand on each others’ shoulders – there are very few if any islands out there.

And so it is with zHome.  In particular, there are several of specific zero energy or close to zero energy projects that inspired it – specifically, the Sensible House in Seattle, and BedZED and Hockerton in England.  I want to highlight each of these projects, and this will be the first of several posts on this subject.

Jon Alexander, Builder, Sensible House

The Sensible House was built by a friend and mentor of mine, Jon Alexander of Sunshine Construction.  Jon is one of the very earliest builders in Seattle to get involved with green building, and is truly a pioneer.  He began thinking about and applying principles in the 1980’s.  He is also one of the founding members of the Northwest Eco-Building Guild (www.ecobuilding.org).

The Sensible House was built as a personal residence for Bob Scheulen and Kim Wells, who were directly involved in its design and construction.  Bob himself has had a long time interest in green building, and maintains a great web site  dedicated to the house and how it works.

I first visited the Sensible House just as it was finishing construction about five years ago.  It remains in my mind as one of the greenest, if not the greenest single family home in the Seattle area.  It includes double wall construction, a structural insulated panel roof, very cool triple paned windows from cold Alberta, as well as a hybrid water based heating system with solar hot water pre-heating.  According to a presentation that Bob gave a couple of years ago, the house isn’t quite achieving zero net energy – but it is darn close, within 15% of zero or so.  Lots of neat green materials are included throughout the house as well.  The web site is a great technical resource, and Bob has added additional information about the home over time.

I was in awe of the house when I first visited it, and continue to be – it is a very early pioneer locally of ultra-sustainable housing.  It is safe to say that the Sensible House is a direct inspiration and parent to zHome.  I want to recognize and honor Jon, Bob, and Kim for their trailblazing in green, low carbon building – without you and other projects such as BedZED, zHome would have been much more difficult to envision and design.