Monthly Archives: January 2014

Right as Rain

Hawai'iLife at Maya Creek has developed a seasonal rhythm and each has its pros and cons.  Despite the cold weather, winter has its perks.  It’s my vacation time, and I was lucky enough to miss out on the polar vortex during a month long trip to Hawai’i.  Also, since I work from home I don’t have to leave the warmth of the cabin very often as I would if I had to make a treacherous drive to work on a daily basis.  Cabin fever can become an issue, but I have good company and make a point to venture out for socializing regularly.

When winter first arrives I’m excited to take a break from all of the projects, but after just a month or two I start itching to get my game plan together for the coming year.  When your projects directly improve your quality of life there’s a lot of incentive to figure out good solutions that will improve your life the most quickly.  It’s been at the top of my list for awhile, but this year I’m finally going to tackle the water system.  That’s right, after 5 years I will finally have indoor hot showers on demand that don’t involve pots of hot water and a cup!

I’ve had a general idea of how I was going to do the water system, but after a lot of research and brain-storming I think I have a pretty good idea of how I’m going to deal with several of the problems I’d been mulling over.  I’d like to share what I’ve got planned so far.

I’ll be catching rainwater instead of digging a well.  There are a couple reasons for this.  Wells are expensive to dig and can cost ~$8,000 in this area.  Because of over-pumping for agriculture water tables are dropping world wide, so deeper and deeper wells are required with more powerful pumps needed to pump the water.  An old woman who lived at Maya Creek as a child recalled a spring on the property, which no longer exists because of the lower water tables.  Another reason for not wanting to use well water as the main water source is that well water in this area contain high levels of sulphur which is difficult to remove, can gunk up plumbing, and generally just stinks.

rainwater system

I will be catching rainwater off the 1,300 square foot galvanized steel roof.  Some people worry about increased levels of zinc from galvanized roofs, but according to this testing report on different roofing materials for rainwater collection, the elevated levels of zinc only occur in the first water off the roof in a rain event.  Because there is also a large amount of dust, bird poop, etc in the first water off the roof I will be using a roof flusher to divert the first 15 gallons(10 gallons/1,000 sq. ft. of roof). The gutters will have screens over them to prevent leaves and other large debris from getting into the system.  The downspouts will also have screens to filter out debris before directing the water through the 500 micron gravity water filter and finally into the underground cistern.

The cistern has to be underground to prevent it from freezing.  It will hold ~3,500 gallons of water.  We get about 46″ of rain per year on average, but very rarely do we get less than 25″ which is what I’ll use to show how much water can be caught.  For every inch of rainfall on a square foot of roof you catch .6 gallons of water.  So 1,360 sq. ft. of roof times 30″ of rain times .6 gallons would give 20,400 gallons of water per year as a minimum.  If we got  46″ it would be 37,536 gallons.

The next question is how much water is needed.  Based on my best estimates we’ve only been using a little over 3,000 gallons per year, of course I expect that to go up with longer showers and laundry(praise be!), so let’s say we end up using 10,000 gallons.  Given that an average 4-person American home with consumes 150,000 gallons per year.  One of the major reasons we use so much less water is because we have composting toilets instead of flush toilets.

Luckily our rainfall is pretty evenly distributed throughout the year, but given the 3,500 gallon storage space of the cistern we should be able to handle an inconceivably long 4-month drought at average consumption levels, but I’m sure we would adjust consumption accordingly in such a situation.

4bricks_fullThe hole for the cistern is already dug, though it needs to be significantly cleaned up.  Once it’s cleaned out, I’ll our a concrete floor, build the walls out of cinder blocks filled with rebar and concrete, and then build a wooden frame for the rebar reinforced concrete roof cap.  There will also be a 2′ wide x 2′ deep urbanite(reclaimed concrete chunk) wall mortared around the top of the cistern to protect it from cracking due to frost heave.  The frost depth in the area is about 20″.  The interior of the cistern will be coated with cement meant for holding potable water and will prevent the cistern from leaking.  I was lucky enough to find someone who had built a similar cistern though his is mostly above ground, and I will be pouring a concrete roof cap to avoid issues with the wood rotting.

From there a sump pump will pump the water into two 55 gallon barrels in the loft area of the common house, one for cold water and an insulated one for the hot water.  The water pressure in the house will come simply from gravity, which means it will have only a few PSI of pressure.  I have a shower head designed for the very low PSI, but the low PSI will help reduce water usage in general.

floatswitchBecause I won’t want to pump cold water from the cistern into the hot water tank in the middle of the day which would cool it down before it gets used I will put the sump pump on a timer and turn it on late at night.  The pump will pump water into the bottom of the cold water tank and an overflow from the cold water tank will take the warmest water from that tank and put it into the bottom of the hot water tank to preserve as much of the heat as possible.

In order to turn the pump off when the indoor tanks are full there will be a float switch at the top of the hot water tank which will control the electrical outlet that the pump is plugged into and turn it off once the hot water tank is full.  There will also be an overflow redirected to a drain in case the switch fails for some reason.

two_solar_hot-water_systems-1The hot water will be heated by a simple home-built hot water collector using the thermosiphon phenomenon to circulate the water rather than using a pump.  The idea is that hot water rises, so by placing the collector beneath the storage tank cold water is drawn into the panel from the bottom of the tank and the heated water from the panel rises up from the panel and into the top of the tank.

The collector will be set up so that if another panel is needed they can be easily set up next to each other.  It’s important that pipes are always sloping at least slightly upwards to prevent bubbles from forming and messing up the thermosiphon effect.

I will also be wrapping copper tubing around the rocket stove to heat water in the winter since I will likely have to stop using the solar collector in the winter to prevent water from freezing in it.  However, I’m planning on putting the collector inside of the greenhouse that will be attached to the front of the house to help prevent that and extend its usable season.

I’d been operating under the idea that I needed to finish the rainwater collection system and cistern before getting the solar hot water system working, but it occurred to me that I could actually set up the interior water tanks and hot water system first and simply pump the water in from the barrels of city water I’ve been trucking in.  That way we can go ahead and have hot showers and running sink water months sooner than I’d been planning.