Solar Power isn't Feasible!

Solar Power isn't Feasible!
This cartoon was on the cover of the book "SolarGas" by David Hoye. It echoes the Sharp Solar slogan "Last time I checked nobody owned the sun!"

Tuesday, August 25, 2009

The do-it-yourself endless hot shower: never have to fight over water again

Low-flow shower heads? Nice idea, old paradigm.

No more "low flow" shower heads for this bad boy! No more 5 minute showers! I just took a 10 minute hot shower at a delivery rate of 3 gallons per minute and used only 5 gallons for the whole shower. What?!! That's 18 liters, less than the average for the Cairo poor who heat a 20 liter bastila on the stove and must pour it over themselves in less than 3 minutes. Do the math: with a federally recommended low flow shower head delivering 2.2 gpm you would use 22 gallons for a 10 minute shower. The best available low flow shower head delivers 1.5 gpm, which would use 15 gallons (56 l). The ultra ultra efficient low flow heads deliver 0.8 gpm and that measly shower still uses 8 gal (30 l) in 10 minutes. By using my water recycling pump I used only 5 gal , with a normal shower head that has three settings -- massage, pulse and flow. Try that with a low flow shower head! Annual US family of 4 H2O cost for 5 minute showers w/1.5 gpm head is $44. Ours: $14, and we get 10 minutes!

What we're interested in at Solar CITIES is providing "the other 90%" (the have nots) with the same luxuries the 10% haves have, WITHOUT increasing our ecological footprint, without using substantially more energy or water or other resources than the world's "poor" already use. The idea is to raise the standard of living world-wide, not lower it.

How do we do it? Read on below!



The Flex Your Power website is a comprehensive statewide resource for energy efficiency, providing information and tools to help California consumers and businesses save energy and money.

Cost-Effectiveness Example
Performance Base Modela Recommended Level Best Available
Water Use Only
Gallons per minute/cycle 2.5 gpm 2.2 gpm 1.5 gpm
Annual Water Use 18.250 gallons 16,060 gallons 10,950 gallons
Annual Water Cost $73 $64 $44
Lifetime Water Cost $590 $520 $350
Electric Water Heating
Annual Energy Use 2,370 kWh 2,120 kWh 1,540 kWh
Annual Energy Cost $142 $127 $92
Lifetime Energy Costb $1,070 $960 $690
Lifetime Energy and Water Cost Savings - $200 $600
Gas Water Heating
Annual Energy Use 131 therms 120 therms 94 therms
Annual Energy Cost $53 $48 $38
Lifetime Energy and Water Cost Savings - $100 $350
aThe flow rate of the base model just meets the current Federal standards for showerheads.
bLifetime energy cost is the sum of the discounted value of annual energy or water costs, based on average usage and an assumed showerhead life of 10 years. Future energy price trends and a discount rate of 4.1% are based on Federal guidelines (effective from April, 1998 to March, 1999). Future water and wastewater treatment costs are conservatively assumed to increase only at the rate of inflation.
Note: Metric Conversions: 1 gallon = 3.8 liters By reducing the demand for hot water, a household reduces the amount of energy needed to heat the water. In this way, a low-flow showerhead helps to cut the emission of 376 pounds of climate-changing carbon dioxide each year and a faucet aerator helps to prevent the release of 83 pounds of carbon dioxide per year.

In Germany we pay 3 Euro for every cubic meter of water, about 4 times more than Americans. And our energy costs are 4 times higher too. But this doesn't stop us from living a quality life style and paying LESS for each "unit of satisfaction". The trick is always to "do more with less". The idea is to achieve high efficiencies and Pareto optimality wherever possible.

The Culhane Endless Shower:

I've finally created an easy easy easy way to take almost "endless" hot showers using hardly any water or energy. Recycling 25 liters (6 gal) to 50 liters (12 gallons) of solar or biogas heated bath water is enough to luxuriate in a half an hour long shower using a simple 12 volt RV water pump and a 12 volt 7 amp hour hobbyist battery. Imagine never having anybody tell you to "get out of the shower -- you are going to cost us an arm and a leg" or "you are using all the hot water, get out so someone else can take a shower" again. Imagine if we could stop the regional and international conflicts over water! The 12 volt Flojet (or Surflo) 3.5 gallons per minute water pump is run by a 12v battery charged by a 200 dollar 55 watt solar panel each day for over an hour of showering. When I finish the housing the unit will be portable and can be taken to countries that experience water stress and life-threatening water wars to supplement our Solar CITIES Solar and Biogas water heating systems. As for me, I'll never go back to using a regular shower again...

Back when I was a kid in the late 1960s and early 70s, before the OPEC Oil embargo, we didn't think much about water and energy costs (they were heavily subsidized and thus appeared cheap), but that doesn't mean we weren't conservative. My grandmother, Isabel Culhane, who raised our parents during the depression and the rationing of World War II, was a paragon of recycling, victory gardening, second hand shopping, do-it-yourself pride and conservation.

Every summer Grammie would hold a "grandchildren's camp" at "the house that Jack Built" on Montague Road amidst the cornfields of rural Rockford Illinois. She would invite her 16 grandchildren to fly, drive or bus in to her midwest country abode from all over the U.S. (as far away as New York and San Francisco) where she would instill in us frontier survival values and the American can-do ethic. We would visit Maury Patrick's farm and spend two or three months learning how to sheer sheep, card and spin their wool, gather berries and bark and make our own dyes and pies, and learn weaving, wood carving and other pioneer day skills. Occassionally a mid-west storm would knock out the electricity and we'd be forced to "rough it"; like my hero, naturalist Georges-Louis Leclerc Buffon (1707-1788) , I used to gather lightening bugs ("fireflies") in mason jars to make my own disaster proof lanterns to read by under the covers. We thought it was grand fun.

What we didn't like, however, was the limited amount of hot water. Imagine: 16 grandchildren, a grandmother, and a guitar playing, prank playing and sometimes irascible Uncle Mark all sharing ONE bathroom for an entire summer, every summer for years, and a mere 80 gallon hot water tank for all those guests. The rule of the house was "you must take short showers and use as little hot water as possible". Otherwise -- no hot water for anybody.

It never occured to us in those days to build a solar hot water heater. It never occurred to us to install a tankless hot water heater (instant on-instant on-demand). America didn't offer up such consumer goods in those days (it would take 40 years and the end of a series of oil administrations before we would see these things become marginally common place in the good old U.S.A). Instead we would fight.

Uncle Mark would boom to my brother (who had a penchant then, and still does, for languid daydreaming in the shower) "Michael, get the hell out of the shower, your time is up!". Grammie would intone "girls, please take shorter showers so the boys can get in" (girls got first dibs of the hot water tank at grandchildren's camp -- common courtesy, women and the little children first).

I remember vowing that one day, "when I grow up -- I'm going to be able to take endless hot showers. Nobody will EVER tell me to cut my shower short again."

Fast forward to Egypt in 2005 when Sybille and I moved in to an unfurnished apartment in Cairo, and found that we could not afford to put in the four electric hot water heaters that the plumbing of the building demanded. We spent a miserable month heating water on the stove and pouring it in the bath until we learned enough and were able to use social capital to construct a solar hot water system. Once that was done the rest of our time was quite enjoyable, providing we stayed within the limits of the 200 liters (55 gallons) of hot water that we could heat each day.

We went on to form Solar CITIES and build and install three dozen solar hot water systems and 5 urban biogas systems in poor communities in Cairo, a feat that earned us a National Geographic Emerging Explorer Award in 2009. You would think we had the hot shower thing licked.

But for all our success in do-it-yourself hot water goodness, two things kept gnawing at me. 1) The idea that when taking a hot shower, all the heat you have expended so much money, time and effort capturing falls on your body for mere seconds before tumbling down the drain -- a huge and unconscionable waste that belies our efforts to help "the other 90%". 2) the sheer amount of water used, hot or cold, just to stand there and feel a waterfall on your body can not be justified in an era when fresh water is in short supply and people are fighting water wars in India and other nations that are claiming lives.

How to construct an endless hot shower that allows the luxury we crave without the resource wastage we decry?

I had done some experiments on the subject when I was a resident of the Los Angeles Eco-Village from 1999 to 2003, but hadn't put them into long-term effect. In Germany, where water costs over 3 Euro per cubic meter (the most expensive in the world), even though we have a fancy vacuum tube solar hot water heater, I was feeling miserable because of the sheer amount of water we were wasting every day (we could see it because we collect all of our gray water in a tank outside the bathroom window to flush the toilet and irrigate the rooftop garden). Between me and my wife and our baby son we were using up 1000 liters every two days. The water bill at the end of the month was a shocker. So it was back to taking short showers, solar heater or no.

Tonight I decided enough is enough. Frank DiMassa and I drove to RV specialists in Santa Rosa (on Yolanda) where Curtis, the owner, sold me a Flojet Premium Quiet Quad Model 4406-143 Type IV 12 Volt self-priming RV water pump (3.2 gallons per minute, consuming 3.3 amps). It cost $95 dollars. I also bought an in-line filter for it. The rational (which I used when I took my L.A. Eco-Village apartment off-grid for three years): Imagine your home to be a mobile-home without wheels. An RV that you use for living instead of recreation (an LV?).

By outfitting my static home with solar panels and a 12 volt water pump run off of a 12 volt 7 amp-hour sealed hobbiest battery (you can find them at Home Depot for security gates), just like you would in a mobile home, I have finally achieved the holy grail of an endless hot shower.

Well, not quite endless, but at least a half an hour to 40 minutes of hot water, without using more than 50 liters (13 gallons) per shower. I can even get it down to 25 liters if I want to, and still get about 30 minutes out of it. I've found that after 30 minutes I'm sick of being in the shower anyway. So for my purposes, the shower is endless. 25 liters can be recycled through a slow sand filter water purifier and used again the next day, so it is in some sense endless if you use recycled water.

The set-up is very very simple (see picture). The pump (which is very very quiet) sits on a table in the bathroom. it is connected to a little 12 volt battery which will be recharged by the solar panel. It has an on off switch and a 10 amp fuse in line with the positive wire. The water intake is fitted with a 1/2 inch hose adapter and 10 feet of hose. At the end of the hose is the in-line water filter that Flojet makes for the pump. This prevents hair from getting into the pump. The water outflow is a 1/2 " thread connector connected to two flexible shower hose for length (joined by a male-male 1/2 " nipple). Before the shower head itself I put a fixture that lets me turn the water on or off; this also turns on and shuts off the pump automatically without having to get out of the tub to flick the switch on the battery until I'm nice and dry (the pump senses a lack of water flow and shuts off by itself).

And that is it. Now I fill the bathtub with just enough hot water to cover the in-line filter (which sits at the bottom of the tub where the soap bubbles don't hang out) and then start showering. Since the pump is self-priming I don't have to do anything. The water stays warm far longer than I care to stay in, and I can just forget myself, daydreaming, shampooing, shaving, massaging sore muscles. Nobody can EVER yell "get out of the shower, you are using too much water" or "too much electricity" or "too much gas" or "you are using up all the hot water, leave some for somebody else." That 25 to 50 liters is MINE to use for as long as it stays warm. And you can actually get two or three showers out of it if you keep each shower to 15 minutes or less.

Improvements: I will build a nice water-tight, vibration proof housing for the pump and the battery with the switch on the outside so it can be easily carried to any bathroom anywhere and instantly set up, and will make it a portable endless hot shower to be taken to arid countries where people are fighting wars for a resource that should never be in short supply.

We live on a water planet. As Silvia Earle said, "we should call this the planet Ocean, the planet Water". There is so much of it!
Wouldn't it be nice if we no longer had to fight to use it?

Kabir liked this on facebook.

Culhane replies:
Thanks for liking, Kabir. I was galvanized into action when IYCN (was it you?) posted the link about the water wars in India that were claiming so many lives. I can't any longer take long showers without thinking about all the people who not only "have not" but are dying in the struggle to have very little. This is National Geographic's Water year. So between the Shmutzdecke slow sand water purifier we built on our porch and this little water recycler we have new projects to bring to Cairo this October and hopefully around the world. Try this out -- it really is simple and effective. Cheers, T

Mustafa liked this on facebook.

Culhane replies:
Thanks for liking Mustafa -- I will hope to bring a working model to Cairo in October. Meantime, check and see what the price of a 12 volt water pump is in Egypt. What is happening with your house that collapsed? Are you moved into your new place in Darb Al Ahmar? Have you been able to put up the solar hot water system? How is your family? What a tragedy you faced! If you get in touch with Omar Nagi and Hanna (who is about to have a baby) and with Hussein Al Farag this week you might be able to connect with Kimberly from National Public Radio who is there looking at Solar Hot water and biogas and the Solar CITIES initiative. It would be great for you to connect with everyone! I will facebook friend suggest them to you.

Elisa commented:
5 minutes is plenty of time for a shower - why should anybody take a longer shower unless it is a medical/life sustaining measure. great for large families where 5 minutes of hot water per person may be a luxury - to the others of us who want to 'luxuriate' under hot running water i say 'suck it up'. get clean & get out:-)

Culhane replied:
Good point Elisa, but old paradigm. Since my energy costs are nil to null (solar heating and PV for the 12v battery) and my water use over 10 minutes is lower than the lowest ultra low-flow shower-head using 5 minute shower taker (i.e. about half of what the miser would use), what would the objection be? Everyone else is simply throwing water and heat down the drain that only passed over their body for mere seconds. That is the travesty. With my recycling shower the same water and heat is used over and over again until the heat is gone. And then the water is used to irrigate the garden and flush the toilet.

Amanda liked the link on Facebook.

Culhane replied:
Thanks for liking Amanda! One thing I neglected to mention is that if the bathroom is well insulated (double pane glass windows etc.) the same 5 gallons can last even longer than 10 minutes -- it is all about delta T -- the temp difference between the water and the air.  If the bathroom (or shower stall) is warm and steamy the hot water just cycles around and around and around without losing heat to the air. So a 10 minute shower can turn into a 20 minute shower without using any more water or heat energy (and just about 30 watts for the pump, easily supplied by solar).

Sybille liked the link on Facebook.

Culhane replied:
Thanks for liking the link Sybille. We should be able to cut our expensive German water bill (where water costs us 3 euro every 1000 liters, which is currently every couple of days, the most expensive water in the world!) down to a fraction of what we are now spending. I know that our greywater is recycled into the rooftop garden and the ... Read Moredownstairs garden and flushes our toilet, so we don't waste it, but now imagine that a 10 minute shower won't use more water than two toilet flushes! That is gong to be amazing, huh? The idea for our Solar CITIES project should be to provide the same luxuries to the 'have nots' that the 'haves' have, WITHOUT raising the ecological footprint at all! I think it is achievable if we rethink the way we do things.
Posted by T.H. Culhane at 12:08 AM

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