Thursday, January 31, 2013

Controlling heat loss

I am always impressed with the winter survival strategies of animals: bears that metabolize their fat, inactive frogs that nearly freeze and active birds that drop their body temperatures.  This last thermoregulation strategy – reducing body heat to minimize heat loss – is one that has direct human applications.

Ducks in an icy lake
In the winter, ducks swim in very cold water and stand around on ice.  Why don't their feet freeze?  Why doesn't their body heat quickly drain through their feet, slowly cooling them?  How do duck feet work with the rest of the duck body to keep it alive in the cold?

The winter physiology of ducks is a marvel of biological engineering, where many sophisticated systems come together to sustain a warm-blooded animal in a very cold environment.  For the purposes of this blog post I will highlight only one aspect of duck physiology – reduced foot temperature – which is beautiful in its simplicity.  First, a question:

On a winter morning, which will lose heat faster.
A) A hot cup of coffee
B) A can of cold soda

Answer: A, a hot cup of coffee will lose its heat faster than a cold can of soda. *if your dying to know why, click here.  It makes sense, then, from an energy conservation perspective for a duck to maintain a lower body temperature in winter.  The obvious hiccup with temperature reduction is that bodies need to stay warm enough to carry out their biological processes (which are temperature dependent); simply reducing body temperature could result in a loss of the body's function.  The duck does a wonderful job of keeping its body functioning while reducing its temperature.  It does this by breaking its body into different heating zones. 
A temperature diagram of a common gull.  Like the mallard duck, this gull sustains a high temperature in its core, but – to conserve energy – allows its legs and feet to cool dramatically.   
So what does cold bird feet have to do with Living Lighter on the Land?  The Armstrong House is actually a lot like the duck – they are both broken up into different 'zones' and which are heated differentially.  Once the Armstrong House's heating system is completely finished it will be broken up into different heating zones (which roughly correlate with the different rooms), where some rooms will be kept at lower temperatures to reduce heat loss.  By slightly reducing the temperature in less-used rooms or rooms that don't require much heat, the Armstrong House's overall energy consumption is reduced.  Also, the different zones can be managed to have their temperature's fluctuate over time.  For example, the whole house temperature can be reduced at night and specific zones can be heated in the morning in the order in which they are used.  For instance, the bathroom can be heated first, then the kitchen, then the office.  In fact, the zones can be managed to reflect the occupant's schedule.  Zones that are unused during the day (bedrooms and master bathroom) can be lowered until 4:00 pm – just in time to be warm for the occupant returning from work.  Likewise, primary rooms where the most time is spent (like the kitchen and living room) can be grouped as a zone that stays warmest.  The mud room, sun room and work room can be zoned together and kept cooler. 

In surfing the web I found a neat house in Vermont that is similiar to the Armstrong House.  They too understand the benefit of zoning their house and heating based on use (see below). 

The three heating zones of 'Perfect House', an energy effecient house in Vermont. 
I love my warm and cozy house, so I am certainly not advocating for living in an icebox.  I am convinced that a comfortable environment can be kept inside the home and energy can be conserved by strategically managing the temperature of various zones.  If the mallard duck can stay active in a half frozen pond, we can surely figure out better ways to thermoregulate our houses to conserve energy. 


Tuesday, January 15, 2013

Mid Winter Compost Tip

Here is a compost trick:

If you throw whole eggshells into your compost heap you are likely to get small pieces of egg shells in the finished compost: not ideal.  Manually crushing up your eggshells before you throw them into your compost pile will help them break down faster and more completely.  See the following pictures:

I save a bunch of old egg shells in the fridge and grind them all at once.  

I lay all of the eggshells in a cookie sheet and then dry them, one of a few ways. You can bake them in the oven at 170 degrees for an hour or so.  In the summer you can just put them in direct sunlight on a hot day.  I have also seen people put their egg shells over the grill on a long day of cooking to let the waste heat dry them out.  The goal is to simply dry out the eggshells and make them brittle.  However you achieve this will be fine.  *Be sure to keep your work station clean when handling wet egg shells so you don't accidentally spread or ingest harmful bacteria.  Wash your hands and materials well*    

I use a large mason jar to crush the egg shells.  The dry shells should break easily.  

Crush, crush, crush!

It only takes a minute to crush up all of the eggs.  

I will stick the crushed up egg shells in the fridge and await spring.  It is best to incorporate these nutrient rich food items directly into active compost.  I am afraid that if I throw the eggshells in my half frozen compost now, the rain and snow will wash them away.  

It is mid January, which means we have another two months or so before 'compost season' opens.   Even in winter you can be improving your compost skills and planning for next spring – make sure you are saving the ash from your fire place and eggshells from breakfast!
Interestingly, the same thing can be done to your eggshells if you want to feed them to your backyard chickens.  If you crush up your eggshells really well, you can add them to your chicken feed and recycle the calcium.  Recycling = Living Lighter on the Land   

Wednesday, January 9, 2013

Energy efficient refrigerator

When designing the solar system for the Armstrong House we calculated a number of 'load estimates', which aim to predict the house's energy consumption.  To provide a generous amount of comfort for the Armstrong House residents we needed to account for every little device they were predicted to use.  Imagine doing a load estimate for your house.....think about all the things you plug in:

DVD players, TVs, computers, hair dryers, coffee makers, blenders, lights and lamps (30 of them), stereos, cell phones, washing machines, garage door openers, video games, WIFI routers, toaster, microwave, water pumps, printers, fax machines, radios... the list can go on and on.  Some things you only use sporadically - like Christmas lights - so their overall burden on the electricity load isn't great.  Other items, such as your refrigerator, never quite - they just keep working away, 365 days a year.  These are the appliances that could end up pushing you over your electricity budget.  At the Armstrong House we invested in an energy efficient fridge/freezer called the Sun Frost RF 16, which boasts many technological advancements over your 'traditional' refrigerator.

Check out their brochure below or click here to see it in a PDF version.

Sarah Bush showing off our Sun Frost RF 16 refrigerator.  Loki the cat in the foreground.  

The walls of our freezer and refrigerator are quite thick, which means great insulation.  

Refrigerators become less efficient when their motors get dirty.  On our Sun Frost RF -16 the motor is on top where it can be easily cleaned.  

Remember, when you are trying to cut down on your household energy use you must address the appliances that run frequently like your fridge/freezer, computer (if you work from home) and dishwasher.

Wednesday, January 2, 2013

2013: A new, cold year...full of fresh greens

Happy New Year everyone.  Here in Pound Ridge, NY the temperatures have hovered around 30 F. for the past week.  Two storms dropped a total of 6 inches of snow on us after Christmas and in spite of the cold we continue to eat fresh salads at the Armstrong Education Center.  How is this possible?  With the use of 'cold frames'.      

The simple anatomy of a cold frame
Cold frames are just little boxes that trap and retain heat.  Just like a greenhouse, these little garden tools are used to create an interior growing environment that is warmer than the exterior environment.  It's all about the sun.  In the northern hemisphere, cold frames face the south and they are constructed and positioned in such a way that they collect as much direct light as possible during the day.  Notice that in the picture below the back wall is higher than the front wall.  When the transparent lid is placed on top of both these walls it sits at an angle facing south, toward the sun.  Inside the cold frame the soil heats up and the air is kept warm throughout the day.  Any insulation that is added to the cold frame helps to keep the air warm after the sun goes down.  In Pound Ridge, NY the climate allows us to grow a wide variety of 'cold hardy' greens, whiche are varieties of greens (like kale and lettuce) that can grow at cold temperatures and tolerate freezing temperatures.  In general, your summer varieties of greens will do poorly in a cold frame in January - stick with the 'cold hardy' greens.  Here is a list of what we are currently growing:

Forcea lettuce
Red Russian kale
Green kale
Purple mizuna
Italian dandelion
Pac choi
Tat soi, and
Hardy white scallion    

A cold frame is essentially a small, south facing green house used for extending the growing season.  The picture above shows the basic design, on which more bells and whistles can be added   

The following pictures were taken at the Armstrong House on New Years Eve, 2012.  You can see that snow is no problem for our cold frames - the little plants inside continue to thrive.

Our rectangular cold frames sit on the southern side of the Armstrong House.  You can see there that we removed some snow from the plexiglass on the cold frame's right side.  

A close up picture of the cold frame lid.  Can you see the condensation on the inside of  the plexiglass?  That is a great sign because it means that the temperature inside the cold frames is warm enough to evaporate water from the soil.  

Harvest time!  My partner Sarah Bush picks kale from one of our cold frames.  Examine the cold frame's construction: we used straw bales as insulation and lined the cold frame's inside with a thin reflective insulator.  Currently, our lid is not attached to any part of the cold frame - it just rests on top of the straw bales.  This method is not ideal for the long term but it seems to be working for now.      

Sarah Bush harvesting greens from our second cold frame.  You can see that on this 30 degree day, Sarah (a Tennessee native) is dressed for the cold.  The 'cold hearty' greens in our cold frames do just fine through the winter.  

There are hundreds of cold frame designs out there - many of which can be made with recycled materials. Just look at all the cold frames on Google images. Your cold frame design will vary depending on your growing goals, your space, your winter climate and your materials.  As long as you are achieving a warm temperature inside your cold frame, you are doing it right.  The straw bale cold frame pictured above is not a permanent structure because the straw will eventually rot and loose its ability to insulate.  In the future we may continue to use temporary straw bales or we may choose to design and construct a permanent cold frame. The sky is the limit.

Want to learn more?
The book Four Season Harvest by Elliot Coleman describes how to successfully grow food through the winter.  Elliot has mastered season extension through his work up in Maine.  Here in Westchester County, Stone Barns uses and demonstrates many different season extension methods to grow food through the winter.  In fact, it was the Stone Barns Vegetable Farm Manager Jack Algiere who assured Sarah and I that cold frames would work here in New York.    

Happy growing