Massachusetts Zero Energy Challenge Winning Home

This is a very impressive less than zero energy home.  It uses a
combination of reasonable size, excellent thermal envelope, very
efficient appliances, some passive and some active solar heating, and a
PV driven mini-split heat pump for additional heat and cooling.

The end result is a true zero energy house that can be built within a reasonable budget.

I cover a few of the highlights below, but all the details on the house are in the article here...

Performance
The monthly performance chart below speaks for itself.  For the year 2009, the house produced significantly more energy than it used.


Highlights
Double stud, R42 walls insulated with cellulose insulation.
R100 cellulose attic insulation.
Triple glazed R5 windows with R7 interior thermal shutters.
Very good infiltration sealing.
Emphasis on south windows for solar passive gain.
Concrete slab floors for heat storage thermal mass.
Solar water heating
Solar air heating collector to for additional space heating.
Exceptionally efficient appliances and lighting.
Heat recovery ventilation system.
Efficient mini-split heat pump for heating and AC.
4.9 KW grid-tied PV array supplies all electrical power and then some.

Double stud R42 cellulose insulated walls

Total cost of the house without land is $180,000.

Altogether, and exceptional house.

Thanks very much to Doug and Tina for providing this material.

Gary

Some New Stuff

This is just a collection of some interesting (at least to me) items added tot he site over the last week or so....

Harvesting Fresh Water From Fog
Areas with regular daily fogs (e.g. some coastal areas) can harvest impressive amounts of fresh water from the fog.  Nets catch the fog and then channel droplets from the fog into a catch basin. 



Details...

Booklet on "Hot Water From Your Woodstove"
This is a good 45 page booklet from Lehman's describing a couple systems for adding a heat exchanger coil to the firebox in your woodstove to heat water.  Good detail on both thermosyphon and pumped systems, and lots of information on troubleshooting and doing the installation safetly.




Details...




Skysails -- Kites for Towing Ships
These are large kites that can be deployed under favorable wind conditions to reduce fuel consumption.  With favorable winds, fuel consumption can be reduced as much as 50%.
Operation of the Skysails is largely automatic.




Details...



Homes From Cylindrical Grain Storage Bins
A collection of links to homes made from cylindrical steel grain bins.  These homes offer a thermally efficient shape, and some options for good insulation thickness -- plus and interesting look.

Details...









Gary

Bob's Solar Ice Fishing Shack

This is a really simple but very effective solar heating collector that Bob uses to heat his ice fishing shack.


The collector uses the whole south wall of the shack.


The collector is a very simple thermosyphon air heating collector that uses 2 layers of black insect screen as the flow through absorber, and 6 mil poly film as the glazing.

Bob took the time to insulate and seal up the ice shack before installing the collector, which is key to making it work.   On a sunny day, it heats the inside of the shack up to very comfortable temperatures.

All the details from Bob...

If Bob can heat his ice shack with solar, you can surely heat your home, or chicken coop, or barn, ... with solar!

Gary

Zero Energy Homes for the Rest of Us

While visiting St George Utah recently, we found that we were in
town during the parade of homes, so we looked at a few of them.  One of the
display homes was a very efficient home built by Sun-Savvy Inc.  I was very
impressed by this home and the other homes they offer.

Their design combines a very good and very tight thermal envelope, heat
recovery ventilation, passive solar, solar thermal and PV arrays, and efficient
mini-split heat pumps to make a home that should be able to achieve net zero
energy use in the southern Utah climate.  The display home has a LEED
Platinum rating. 

Even more impressive to me is that these are very nice and very "normal"
looking homes.  These homes appear to be very easy for the homeowner to live with. 
While the energy efficiency does add some cost, the homes appear to be cost
competitive with ordinary construction homes.  In other words, these are
net zero or near net zero energy homes which should have a very wide appeal to
ordinary home buyers -- you don't have to be an eco-freak (like me) to like
these homes. 

We took the full tour, got a lot of pictures -- all the details here...

Much more on solar homes here...

Clerestory windows -- great daylighting.  These open automatically when a set temperature is exceeded.


The energy recovery ventilation unit -- an earthtube is used to precondition the intake air to the ventilator.

It seems like a lot of the "net zero" energy homes you see are a long ways
out of the mainstream -- they tend to be architecturally unique (some would say
strange) and come with an acre of PV panels that would add $100K+ to the cost of
the house were it not for some very very generous (and perhaps questionable)
rebate programs.  I don't see this type of near zero energy home ever
catching on and becoming widespread.  On the other hand, a design like the
Sun-Savvy homes seems like it could have very wide appeal.  I hope it turns into a trend.

Gary

Tom's Larger Solar Heating System

Tom sent in the final update on his new solar space and water heating system.  This update covers the storage tank, controls, heat exchanger and integration with the boiler.

This is a really interesting project.  It includes all of the following:

1. Design and construction of a 336 sqft solar collector -- including some new wrinkles on fin fabrication and installation.
2. Building the 410 gallon heat storage tank that doubles as a workbench.
3. Details on the solar  domestic water heating system that utilizes a heat exchanger made from about 200 ft of 3/4 inch rigid copper pipe. 
   
4. Details on implementing the radiant floor heating system that pumps hot water directly from the storage tank and requires no heat exchanger.
5. Details on adding heat input to the tank from a nearby wood boiler in a very simple way.
6. There is even a way to make use of solar heat on seasonal refills of a hot tub.

Tom's system integrates all of these functions in a simple, straight-forward and cost effective design.


Wood boiler heat source as alternative to solar.

Full details on Tom's space and water heating system...

Many other solar space heating projects...

Tom's other projects on Build-It-Solar....

Thanks again to Tom for taking the time to document this project!

Gary

1 Year Report on Gordon's Deep Energy Retrofit

A few months ago, Gordon and Sue sent in a very complete description of their project to completely remodel a poorly insulated and drafty schoolhouse for their residence.  There goal was to bring it up close to Passive House Institute standards.  Through a combination of an external Larsen Frame insulation scheme, added sun space, much sealing, excellent windows, and passive solar gain additions, they have achieved their goal.

The new sunspace added as part of the retrofit.


Gordon sent in the report after one year.  It covers performance to date (very good), and some fixes they have made to some problems that have come to light while living in the new home.

The very detailed report on the original project, including report, many pictures, and thermal analysis spreadsheet...

The 1 year update report, including performance to date, problem fixing, and updated thermal analysis spreadsheet...

This is the most carefully planned and executed energy retrofit I have seen, and it's really nice to see it living up to expectations.

Gary

Energy Fairs

This is the season for a lot of the annual energy fairs, so check around and see if there is a good one to go to in your area.

The fairs are a great way to learn about renewable energy projects, go to workshops, meet some renewable energy people in your area, and find some deals.

I keep a list of all the Energy Fairs I know about here...

If you know of others that are not on the list, please let me know...

Gary

An Exceptional Residential Energy Retrofit

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Gordon and Sue took a drafty 1963
brick schoolhouse with almost no insulation and converted into a home that
could meet Passive House Institute standards, and that has a heating bill that
is 6% of a similar size code built home in their area.   Building a
new home with a thermal envelope this efficient would be an excellent
accomplishment -- doing this in a retrofit situation with all the challenges
that go with trying to bend an existing structure to your needs makes it much
more difficult.   Meeting nearly all of the space heating needs with
a good thermal envelope and passive solar heating was a very difficult
challenge in this tough 7,150 heating degree day climate in Ontario.  On
top of all this, the house looks normal and fits into its neighborhood just
fine.

Full details...





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This is the most carefully thought
out and carefully executed energy retrofit I have seen.  

Some of the features of the retrofit include:
R40 Larsen Truss walls, triple glazed R6 super windows, glazing revamped for
passive solar heating, a new solarium, a hand crafted masonry heater, and much
more.  In addition to a very good thermal envelope, Gordon gives a lot of
attention to fire safety and to redundancy in the space heating system. 
Like most good designs,

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this
one is simple and robust without a lot of gadgetry.



Gordon has done a very good job of describing the logic leading up to the key decisions on the insulating, glazing, passive solar, and thermal mass solutions used in the final design.  He has also described some of he things that did not go so well, and why -- all good information for would-be rettrofitters.

 

The
full details include a 30 page description of the design and construction
process, an extensive photo gallery covering all stages of the project, and a
very detailed thermal analysis spreadsheet.  

 Gary

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