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Friday, June 26, 2015

Solar panel and equipment warranties

Note: this is a revised re-post from my old defunct blog

A year ago I was using the Enlighten web interface for the microinverters on my solar array and noticed immediately that one of the solar panels was dropping out at different times of the day and producing only 1 or 2 Watts.  (Microinverters convert DC from the solar panel to 240 Volts AC that feeds into the building and electric grid).  The Enlighten user interface lets me replay the energy produced by my array throughout the day showing Watts produced per panel and the brightness of each panel representing relative power output.  This system granularity is a very helpful tool and is one of the best features of using micro-inverters because you can isolate and identify issues at specific panels very readily.
screen shot of Enlighten web portal
I emailed Enphase tech support and they responded by saying that they would try uploading new software to the microinverter behind that panel.  (Doesn't it blow you away that they can do that!).  A week later the panel dropped out completely and was no longer producing any power so I called tech support and talked to very helpful person who explained that they had tried the upload and it had not worked so they had already issued a replacement microinverter.  Apparently inverters tend to fail within the 1st 2 years of operation and it is unusual for one to fail after 4+ years.

Enphase inverters have a 15 year warranty and solar panels ALL come standard with 20-25 year warranties.  Once the replacement inverter arrived, it was a relatively simple matter to shut down the array and go up on a couple of ladders with my neighbor and remove the solar panel to access the inverter.  At which point it is largely plug and play to replace and then bolt down the new inverter and solar panel.  Here is then new microinverter:

And now I am back to normal again:  
The value of my solar power system is enhanced by excellent warranties and customer service.  I hope that by sharing this experience I will allay any concerns my readers may have about their potential investment in solar energy.

Wednesday, June 24, 2015

Safe disposal of unused medications

Last year I had to have emergency surgery and the hospital prescribed some opiate painkillers for my recovery.  I only took one or two of those pills because they made me feel so woozy, and the pain was quite tolerable with a little help from ibuprofen.  Recently I looked at that bottle of painkillers in my medicine cabinet and decided to dispose of it safely.  I am quite aware that there has been a significant increase in the abuse of opiates nationally and here in the state of Maine.  Apparently some house break-ins are now being attributed to drug addicts looking for opiates in medicine cabinets.  Medications are typically placed in the trash or dumped in the toilet, neither of these options are environmentally responsible.  In previous years, my wife and I would take our unused medications to an annual return drive at one of the local fire departments. 
Me disposing meds in the MedReturn box at our local police station
Last year there was a big push on a national level to make it easier for people to keep these dangerous narcotics and pharmaceuticals off the streets so now there are return boxes located in police and sheriffs departments throughout the country.  This makes it very easy and convenient to safely dispose of these potentially dangerous medications.  Here is a good article in the New York Times about the new return policy implemented by the DEA.  To locate a MedReturn drug collection box near you, you can go to their website: http://www.medreturn.com.  Medications are collected and responsibly disposed, typically by incineration.  They have a map you can use to search by ZIP Code and I found 5 drop-off sites within 10 miles of my home.

The other reason it is a good idea to dispose of these medications this way is to keep these chemicals out of the waste water treatment plants which cannot process them.  For instance, when birth control pills containing synthetic estrogen or other hormones enter the waste water stream they can have significant adverse effects on aquatic life. According to this NPR article, it has caused some species of male fish to become feminized, even causing them to produce eggs in their testes.  The issue can be severe enough to cause a collapse of an entire fish population resulting in near extinction.

From a sustainability standpoint is up to us to take full responsibility for all aspects of our waste, particularly to protect the environment from harmful side effects of these chemicals entering our streams, rivers and lakes.

Sunday, June 21, 2015

Solar water heater benefits and ROI


Back in 2006 I decided to install solar collectors for the domestic hot water system in my home in Maine.  At a purchase price of around $3000, I calculated that it paid for itself within 4.6 years (after incentives) by reducing use of propane to heat domestic hot water by nearly 50%.  I did do some modifications of my own to improve performance and I expect to save well over $11,000 in propane costs over 25 years.  

I enlisted friends and neighbors to assist in the installation and it went quite well.  Just a few hours one afternoon to get the collectors mounted, and a few more afternoons to do all the interior wiring and plumbing.

I wrote a detailed blog about the installation on my website that details the entire process of installing this well-designed kit.  I purchased the kit from Butler Sun Solutions in California and could not be more pleased with everything they provided.  The system has required little to no maintenance and continues to perform extremely well.

http://www.arttec.net/SolarDHW/13_Live%20stats/
The chart above shows two days worth of temperature readings for the collectors and storage tank from June 17 and 18, 2015.  Click on the image to see a live version of this chart on my website.  Because the collectors are mounted vertically to the south facing wall of my house, the performance is a little compromised during the summer when the sun is higher in the sky.  (Solar collectors for work best when they are pointed directly at the sun).  I get best performance in spring and fall when the sun angle is lower and the temperatures are moderate.  Water from our well comes into the house at approximately 55°F and temperatures in the storage tank can exceed 110°F after a good sunny day.  Performance is quite good in the winter depending on outside temperatures which remain below freezing for most of the winter here in Maine.  

Preheated water from the solar storage tank is fed directly into a propane tankless demand heater that I installed in 2010 to replace the old tank water heater that failed.  By feeding pre-warmed water into the demand heater I am dramatically reducing the amount of propane needed to bring the water up to temperature.


The image above diagrams the complete system and makes it look relatively simple.  If you are comfortable doing basic household plumbing and carpentry, then this DIY kit is an excellent choice as a retrofit to reduce the energy consumption in your home and I cannot recommend Butler Sun Solutions highly enough.


Thursday, May 28, 2015

Tankless water heater annual maintenance - flushing with vinegar!

Back in 2010, our propane fired water heater tank sprang a leak and I took this as an opportunity to install a tankless on-demand water heater (detailed blog).  These heaters are much more efficient because there is no heat loss from a large tank.  When the hot water faucet is opened, the heater kicks on and fires up a propane flame to heat water passing through the heat exchanger.  The moment the hot water faucet is shut off the heater shuts down. 

Like all equipment, this device does require minimal preventive maintenance.  Most people never think to do maintenance on their water heaters but doing so can dramatically extend their life and replacing a water heater is always an expensive proposition.  Recently I blogged about replacing the anode rod in my solar storage tank which is actually an electric water heater that is disconnected electrically.  This has the potential to more than double the working life of that tank by preventing the walls of the tank from rusting through.

Maintenance for a tankless heater is a little different.  You need to take a gallon or so of virgin food grade white vinegar, and pump it through the heat exchanger to dissolve scale build up inside of it.  (Rinnai recommends using 4 gallons of vinegar but I think this is more than is necessary).  While the warranty from my heater is 12 years for the heat exchanger and five years for parts, I believe firmly in doing routine maintenance like this on an annual basis.  My Rinnai heater has valves and hose connections to simplify the process of flushing heat exchanger.

Here are the valves with the fill/drain caps removed:
The flushing procedure involves putting vinegar in a 5 gallon bucket and using a small electric pump to pump water from the bucket through the heat exchanger and back down into the bucket.   I already had a pump and several short lengths of clear garden hose that I use to drain and fill my solar heating systems annually.  I made up the hoses by purchasing clear plastic hose and adding standard hose male and female connectors to the ends so that I can see the fluid moving through them.

Here I have connected the hoses and reversed all of the valves to isolate the heater from the building water supply and switch everything over so that the vinegar passes directly through the heat exchanger and does not enter the building's plumbing:


The image below shows the complete set up:
I wired a foot switch to the pump so that I can start and stop it quickly as needed.  After running the pump for several minutes the water turned slightly turquoise which is the color of the copper plumbing oxide.  This confirms that I am removing scale build up inside the heat exchanger.

Here's a picture showing two bottles of vinegar, the one on the right contains the vinegar I used for the flushing process so you can clearly see the change in color:
By the way, the other use I have for white vinegar is as a natural weed killer.  I use a small spray bottle of 100% vinegar and spray it onto broad leaved weeds in the middle of a sunny dry day.   When the plants are thirsty they try to ingest the vinegar and it kills them quite effectively. I plan to reuse the flushed vinegar as weedkiller which is why I saved it back in the original bottle.

I am aware that I make this procedure seemed rather simple, but it does involve some experience and special equipment.  So if you are not DIY inclined, and you have a tankless water heater, you may wish to hire a plumber every year to perform the flushing procedure to ensure your investment is protected.   Tankless water heaters are significantly more expensive than a tank style heater so there is real value in this relatively affordable maintenance.

From a sustainability standpoint, maintaining equipment like this extends its life - keeping it from the landfill.  When my heater eventually fails, I intend to responsibly recycle as much of it as possible.  The heat exchanger itself contains a significant amount of valuable copper which can be recycled for instance.

If you are looking to buy a tankless water heater, here's a good review of current models: https://www.reviews.com/tankless-water-heater/

Tuesday, May 26, 2015

My solar lawn mower - still going strong


UPDATE 2022 - I "retired" this mower and purchased a new Greenworks mower  performs really well!  Back when I built this mower, cordless electric ones were not available and now there are dozens of models.  I was able to sell the huge motor for $200 and recycled the lead-acid battery.
Over eight years ago years ago I was inspired by a small article in Home Power magazine in which a guy named Al Latham described how he had converted his standard 22 inch gas powered lawnmower to use an electric motor and battery that he charges from solar.   I decided to make my own conversion and have been using it consistently to cut tall grass and weeds in our so-called lawn ever since.

At this time of year I transition from charging the mower from a standard automobile battery charger to using a couple of small solar panels on the south facing roof of my storage shed.  These panels combine to a total of 40 W which is enough to charge the mower in one day of clear sunlight.  The 10 amp automotive charger can charge it up in a few hours.
Gauges on the handlebar show battery Voltage and Amps drawn when the motor is running.  As you can see it draws up to 30 A and can sustain this for 20 minutes or so which gives me enough time to mow a large section of our quarter acre lawn.  

In the middle of the summer 20 minutes is about as much as I can handle because this mower is quite heavy with the very large motor and lead acid battery and it becomes sweaty work.   Nonetheless, it is a delightful mower to use because it is very quiet and powerful enough to cut through tall weeds.

Maintenance involves sharpening the blade every year and replacing the battery every 2 to 3 years at a cost of $60-$80.   So this is definitely more expensive to operate than a gasoline lawnmower, but it has zero emissions and may last significantly longer than one of its gas cousins.

If you want to learn more about the construction of my solar mower, I have a detailed blog on my website with clear instructions on how to build your own.







Saturday, May 9, 2015

Firewood: it warms you twice

wood pile and my workshop building
It is early May and spring is finally here in Maine and we are getting some warm days with temperatures peaking as high as 80°F already.  I spend much of the day in my home office sitting in front of a computer or my electronics workbench where I design and develop electronic products so my days are relatively sedentary and I look forward to outdoor activities at this time of year where I can use my big muscles. 

Each year I set a goal of cutting 1 cord of firewood from our 2 acre woodlot behind our house.  This is just enough to augment the solar/propane heating system for my super insulated workshop,and it is great exercise.  As they say; "Firewood warms you twice, first when you cut and split it, and then when you burn it".
woods behind our house in Maine
The woods behind our house are relatively young - the land had been clear-cut 50 to 60 years ago so we have a lot of small young trees competing for the canopy.  Many of them do not make it and I find them dead or dying.  My strategy for responsible forestry management is to start by harvesting these dead trees or blow downs from the winter storms first.  Very often I will find trees that have been dead for a while and are already debarked and quite dry.  I place this on my pile closest to my workshop door because it will be the driest wood.  Ideally, wood cut from living trees needs to season for a minimum of 6 to 9 months, so my next step is to seek out trees that are crowding each other out and cull them to allow nearby trees to grow to maturity.  

As a sustainable guy, I cannot countenance using smelly fossil fuel powered chainsaws so I have two electric chainsaws.  One is a 14" lithium battery powered cordless saw made by Oregon:
http://www.oregoncordless.com/product/chain-saw-cs250/
Oregon CS250 cordless chainsaw
I use this to fell and de-branch trees back in the woods and then cut them into lengths that I can carry to my cutting station.  I am extremely pleased with this chainsaw, it cuts really briskly and the battery lasts for 20 minutes or so which is plenty of time to fell several small to medium-sized trees and cut them up.  By the time the battery needs recharging, I am usually ready for a break and charging takes about an hour or so.  It also has an unique feature in that it has a built in sharpener.  Best of all, it is relatively quiet and there is no stench of gasoline fumes.  It is also completely carbon neutral since the power for the both chainsaws comes entirely from our solar array.

I also have a Poulan 3.5 hp electric chainsaw that I run on a long extension cord:
http://www.poulan.com/products/chain-saws/pln3516f/
Poulan PLN3516F 3.5 hp chainsaw
This is the saw that I use at my cutting station to buck the logs to 16 inch lengths:
bucking logs in to 16 inch lengths
photo: Rebekah Younger
Finally, I split the larger logs:
splitting a log 
photo: Rebekah Younger
I have spent about three afternoons so far and have prepared about a half cord of wood:
about 1/2 cord cut and stacked
For the uninitiated, a cord measures 4 ft. X 4 ft. X 8 ft. and has a volume of 128 cubic feet. The amount of solid wood in a cord varies depending on the size of the pieces, but for firewood it averages about 85 cubic feet.  Firewood needs to be stacked and left to dry, so I cover the top with a tarp to keep the rain off but leave the sides open until the winter.   Before the first snow I typically cover the entire wood pile with a large tarp.   Last winter we had over 3 feet of snow on the ground and it is important to keep the snow off and the wood dry.

Fortunately, the weather on the days I have been working has been pleasant and in the 60s.  As the weather gets warmer it becomes less enjoyable to work, so I try to get as much cut as I can before the warm weather.  When the heating season starts in late September, I enjoy reminiscing about the specific trees that I cut and split as I put them in the wood stove.  There is also a layer of satisfaction of knowing that I harvested all of the wood myself.  For the house where we use 2 to 3 cords of wood a year, I capitulate and purchase pre-cut firewood that we have delivered.  There is still some sweat equity involved in stacking this wood though! 

From a sustainability standpoint modest use of responsibly harvested firewood is essentially carbon neutral since I am simply shortening the carbon cycle of trees that would naturally fall and decay thus releasing their carbon.  By giving precedence to dead or dying trees, I'm reducing my impact on the natural cycle.

Monday, April 27, 2015

Replacing the anode rod in my hot water tank to extend its life

Every three to six months I connect a hose to the bottom of my water heater and drain a few gallons into a white bucket to remove gunk and the debris that comes off the sacrificial anode rod as it slowly dissolves. The purpose of this anode rod is that it dissolves through a process of electrolysis, and by doing so prevents the walls of the tank from rusting out.  Today, I decided to replace this anode rod, because when I drained water earlier I was seeing rust in the water which is a danger sign that the walls of the tank may be rusting out.  Here is a picture showing how it is installed in a standard electric water heater tank:
It is clearly visible at the top of the water heater tank as the only large nut on the top. 
 


Below is a picture of a brand-new rod, and below it what was left of the one that I replaced:
New anode rod
worn out anode rod
Clearly it had done its job, and I am concerned that the walls of my tank may have begun to rust.  I had to borrow a neighbors half inch ratchet wrench, and purchase a 1 1/8 inch socket.  He helped me by bracing the tank while I used the ratchet wrench with a six-foot pipe extension to break loose the old rod.  Fortunately the whole replacement process went fairly easily, all we had to do was shut off the water pressure and drain a little water out of the tank by opening the drain and the P/T valve at the top to allow air to enter before removing and replacing the rod.

This water tank has been in service for six years as my solar hot water storage tank, and another six years prior to that it was my primary source of hot water.  This should serve as a cautionary tale to anyone with a water heater tank.  It is a lot less expensive to replace the anode rod than it is the entire water heater!

Note: due to the low ceiling height clearance, I installed a flexible rod like the one below.  
Generally they are straight and measure 24″ to 36″ long, and some are even longer.  Your anode rod needs to be sized to match your tank.  Here's a link to the one I bought(as an Amazon Affiliate, I earn from qualifying purchases.)

This is part of my ongoing series that deals with the concept of repairing rather than replacing as a way of living sustainably.  One can argue that living sustainably can save you a great deal of money over the long term, and this has certainly been true for my lifestyle.

 NOTE: The tank finally sprang a leak on July 18, 2015 and I replaced it. More about that here.

Wednesday, April 22, 2015

Understanding solar insolation

Having solar power systems on one's home means that you become very conscious of the daily and seasonal cycles of the sun.  The word insolation is used to define the total amount of solar radiation energy received on a given surface area during a given time.  It is insolation that is used to calculate how much energy you can get from solar panels or collectors for any given location and time.

If you live on the equator you do not see significant
seasonal variations in insolation, but where I live at 44° latitude, it varies considerably throughout the year and it is important to understand this in order to correctly predict how much energy one can extract from the sun.

There is a very helpful web calculator produced by PVeducation.org that produces charts of available solar energy (insolation) for given locations.  I use this tool to create the animation below that shows the available solar energy in Watts/square meter in 10 day increments for the year at my location of 44° latitude North.
I made this animation by taking screenshots at ten-day intervals by adjusting the slider on the calculators webpage.

This clearly demonstrates how the available sun hours per day varies significantly at my latitude.  The chart below shows the predicted versus actual solar energy produced by my solar array and clearly shows the seasonal variations.  The predicted energy was charted using the calculator from National Renewable  Energy Labs called PVwatts which takes into account both seasonal variations and local weather conditions.  The actual data came from monthly energy production reports from my solar array. 
Over the years I have added panels to my solar power system which accounts for the annual increase in output.  If you are considering installing solar power or heating systems on your home it is important to be aware of the seasonal variations and the impact of local weather. 

Saturday, April 18, 2015

Repairing - not replacing our microwave oven

Our microwave oven stopped working a few days ago - it made a loud humming sound and produced no heat and smelled a little smoky.   I took this as an opportunity to blog about repairing versus replacing.   This is a recent model Sears Kenmore microwave oven that was only about four years old and sending it to the landfill is just not something I am willing to do.  So I did a web search on the model number and found a number of suppliers that sell spare parts.  I am familiar enough with microwave ovens to know that the most likely component to fail is the cavity magnetron.  This is the large expensive device inside that converts electricity to microwave energy.  (And no, it is not "radioactive"!   Microwave energy is in the radio frequency part of the spectrum).  I found a supplier that listed a replacement part for about $65 plus shipping and it arrived in the mail this morning.


Microwave oven with replacement magnetron
Most home appliance repairs can be accomplished with little more than a screwdriver, and the only challenge in repairing this microwave oven was that the screws on the back required security bits to prevent ill-informed people from opening up the device.   Fortunately, I already had a security bit set with almost every known type of security screw bit.  Sets like this can be purchased for around $10 in a good hardware store.
security bit set
After unplugging it, it was a simple matter to remove the half-dozen screws on the back, and then I found a couple of simple Phillips head screws on the sides.  Manufacturers are tricky and will often mix and match screw types and even hide screws underneath paper or plastic labels to prevent you from figuring out how to open up their products.  It is also important to document everything as you remove parts so that you can remember how to put them back together again.  This is where a smartphone comes in very handy, or any digital camera for that matter.  Also be careful never to force anything when you are taking it apart.  If something does not come loose easily, it is probably due to a hidden screw or fastener.  Slow down and look very carefully for well hidden screws or catches.  When products are manufactured the components are designed to assemble quickly and easily and so dis-assembly should require very little force.

Having removed the cover, it was easy to identify the magnetron inside:
microwave oven inside with replacement magnetron
The magnetron itself was secured with standard Phillips head screws:
magnetron secured with Phillips head screws
After I unplugged the electrical connection, I removed the magnetron and installed the replacement, and buttoned everything up again.  A quick test of the microwave oven with a cup of water proved that it was working perfectly and actually sounds quieter now.  This whole process took less than 30 minutes and anyone with the desire to do it can do this themselves.  

In our disposable economy I realize that I am somewhat heretical in that I firmly believe things should be repaired and not replaced without a thought.  I hope that anyone reading this will consider repairing a broken appliance themselves.  Not only is it very satisfying to repair something, but it also saved over $100 on the replacement cost of a new microwave oven.

If you are on a tight budget and happen to see an appliance that someone has put out with their garbage, you might want to consider it an opportunity to acquire an affordable appliance with a little repair work.  If you are even more enterprising, you could do the repair and then donate the appliance to a worthy cause!  All of this is something to consider in the spirit of keeping things out of the landfill.

Sunday, April 12, 2015

Interior storm windows - thermal study

In an earlier blog post I talked about the benefits of installing interior storm windows to reduce heating bills in cold climates.   You can purchase these double pane plastic film windows for about nine dollars per square foot, or you can make them yourself for around $1.25 per square foot.   Instructions to build them yourself or on my website.   They consist of a wood or metal frame with heat shrink clear plastic on both sides creating a trapped air layer in between.  They fit snugly into the window with highly compressible weatherstripping that prevents air movement through a leaky window.

I have installed these interior storms throughout my workshop because the original windows were cheap, single pane, double hung units that are very leaky.   When I first closed in the building from being an open barn to a heated space I purchased commercial interior storms, and more recently have added my own handmade ones as well.  For every trapped layer of air, an R-value of one is added.  So starting with a single pane of glass, by adding a double pane interior storm there are two trapped air layers creating and R-value of two, and by adding a second interior storm I am upgrading my original windows by an R-value of 4 which is very significant.

Fluke VT04 Visual IR Thermometer
This evening I decided to document the thermal efficacy of these window treatments using my VT04 Visual IR Thermometer made by Fluke.  The temperature outside was almost exactly at freezing and I started by taking a picture of the window with a temperature reading of the glass surface at 31.7°F:
Then I proceeded to take thermal images of the window itself, followed by each of the additional interior storm windows:
By adding my homemade interior storm window I gained 3.6°F and then adding the commercial aluminum framed interior storm window I gained an additional 1.8°F for a total improvement of 5.4°F.  While I adjusted my thermal camera to compensate for the low emissivity of the reflective surfaces, I cannot be sure these readings are entirely accurate, but they certainly convey the concept.

My homemade window is framed with 1X2" primed pine lumber with 3/4" spacing between the panes, while the commercial one is framed in aluminum with only 1/4" between the panes.  Additionally, the air gap between the glass and my window is between one and 2 inches, while the air gap between my window and the commercial one mounted to the surface of the window framing is around 4 inches.  Larger air gaps are less efficient because they can function as a heat pump as cold air flows down at the colder surface and warm air flows up the warm surface creating a circulation.