Tuesday, February 2, 2016

Well, Well, Wells!

Where I grew up, nearly every summer our well ran dry. My father had an arrangement with our neighbor Charlie to lay a hose down through the woods from his spring to our back yard. My brother, sisters, and I would fill buckets of water from the hose and carry them into the house. On Saturday night, my older sister and I shared the tub, dribbling each other in about two-inches of this hard-won water.  It wasn't a traumatic childhood experience, but it was lousy.

Occasionally, my father, who was always reluctant to part with money when it wasn't a "pretty good deal", would consider digging a new well.  During one of these periods, my mother, who was known to have witchy qualities, decided to try her hand at dousing. She broke off a branch from one of our old fruit trees, and, fists face up, clenching each forked end and with the end of the branch extended straight out, she began pacing the property. We followed impressed and optimistic every time the point of the branch nose-dove into the earth.  A sign of water! (I tried dousing a few years later and experienced this same earthward movement against definite resistance.  I have no idea if the end of the branch was pointing toward water or not, but the magnetic pull was mysterious and unsettling.)  At the time my mother doused, however, in spite of her obvious (to us) gift, my Dad wouldn't risk what could have been a lot of money based on a magic stick and we never had a new well. After my parents sold our house and moved down to Westchester, the new owners hired a driller who went down 6 feet and punched into an aquifer that produced enough water to supply daily baths through all later drought-stricken summers. Ah well.

On my first day of college, I took eight baths, after which tub world became a necessity – a place of meditation, therapy, and warmth. Now, my bath life has come full circle. The bath that was a luxury when I was kid is a luxury once again. Our barn apartment has no tub, so since we moved upstate full time, my only water experience for the last two years comes from our half-assed shower, which spits out mineral-laden water that mysteriously and unadjustably swings sadistically between scalding and freezing.  Years ago on the Upper West Side, deep in pain from my brother's death and the end of my marriage, I sank within the hot healing water of our old cracked tub and experienced the bottom of grief. I miss my baths. I hate my shower.

In our future fantasy house on the site next door, we will have two tubs.  And, in anticipation, we now have a well on the site.  In fact, not just a well for water, but three more for the geothermal delivery of heat. To do this work, we hired Keyser Drilling Company, which, like many small businesses around here, is a multigenerational one. (Dan Keyser Junior, who dug our wells with one other young man, is the great grandson of the man who started the business in 1946.) This winter has been so mud-ridden that Dan and his colleague couldn't start working until mid January, when the ground surface finally froze.  On the day they were able to start, Michael and I walked down to watch. Two red trucks were lodged a few feet from our house site: one carried the casings -- long tubes stacked along the side like fittings for a pipe organ.  The other sported a shaft extending from the back of its bed about thirty feet into air like the main mast on the prow of a ship. Hydraulic tubes and fittings dangled from it, the riggings that would pound the drills and casings into the earth.

They dug the water well first, going down 360 feet and piercing an aquifer with an artesian spring that produced enough water to propel it up the shaft without a pump. Multi-bath time! Over the next three days they dug three geothermal wells, with one producing a gusher twenty feet into the air. Water is everywhere here (raising the specter of a floating basement!).  

Right now each of the geothermal wells, which go down about 300 feet each, has two ends of a tube sticking up like rabbit ears out of their bores.  Each pair of tubes is joined at the bottom of its well to form a loop.  In a week or so Dan Junior and his colleague will come back and push grout up from the bottom of the wells around the tubing to anchor them and seal off the water.

The ecological match-up between our solar trackers and a geothermal system is gratifying. The earth sources the heat for the system, and the sun feeds the solar panels to produce electricity required by the heat pump, the heart of this process.  But how does a geothermal system work, one might ask (although one rarely does).  And can one answer this question without the asker dying of boredom?  And since I am both the asker and, with this blog, the answerer, and since I took only one physics course, which was designed for poets, I risked boredom death to whack through the Google jungle of faux knowledge for geothermal clarification.  Here goes.

The primum mobile of the system is the heat pump.  On its behalf, an ordinary water pump sends a mix of water and glycol (basically anti-freeze) through the loops down into the wells and back to the heat pump.  After about 10 feet in depth, the earth in our region maintains a constant temperature of 47 degrees, so as this fluid mix passes through the tubes it absorbs heat.  Now, when I was idly wondering how this process could actually heat a house to 70 degrees in winter, I was a victim of a popular misconception: that the fluid was heated to the temperature of the earth as it voyaged through the loops and when it reached the house, the heat pump boosted that 47ish temperature up 23 degrees.  Wrong.  As Michael reminded me, "Temperature isn’t heat.  Heat is energy." 

The geothermal system, I discovered, is a slave to the second law of thermodynamics, which I had to look up.  It dictates that when hot and cold bodies meet up heat energy will flow from the warmer to the colder body until it reaches equilibrium. So, in winter when the cold fluid is passing through the warmer earth, an exchange of energy occurs and the fluid warms up. (Heat doesn't move backwards!) As the fluid moves up into the heat pump, the earth-warmed tube passes through another one that contains the refrigerant R-410a – a tube combo called a coaxial coil. Once more, the thermal law #2 police go into action. Liquid R-410a has a very low boiling point and vaporizes into a gas as it absorbs heat even at the tepid earth temperature during this legal exchange of warm to cold.  The gas then passes through a compressor, which squeezes the gas back to a liquid. Heat is released during this process and produces the hot water that will someday pass through coils under our floor, where TL#2 will keep my feet warm.  Ta Da!!! 

And, although still long months away, let us not forget the hot water in the soaking tub poised to enact the second law, exchanging grief and irritation for peace of mind.

(A note: Unlike the refrigerant Freon, R-410a does not deplete the ozone layer. It does, however, have 1725 times the effect on global warming than carbon dioxide.  One trusts that reducing dependence on polluting sources of energy offsets this impact)