Arduino UNO

This is a picture of the micro-controller which I will use for control of the solar hot water heater.  The micro-controller is programmed from a standard computer and the program remains resident on the arduino after that.  It operates on a 7-12 volt source.  There is a hall switch in the linear actuator which pulses every time the actuator shaft turns.  I will have to characterize the number of degrees per pulse as the actuator moves through its travel.  I still need to investigate how to most inexpensively control the motor.  I have purchased a motor control that accepts a PWM input, however, I think that is way overkill and expensive.
I have a 24 volt linear actuator but I hope I can operate it at 12 volts.  My plan is to trickle charge a 12 volt alarm battery and operate electronics and motors off of it. Adding batteries unnecessarily complicates things.
I have been pondering what to do if the machine looses power and therefore looses time.  There is lots of potential for havoc if the tracker is slightly misaligned with respect to the sun because of the intense concentration of light.  I am currently thinking about having a wake up routine where the machine would wake up, determine what attitude it was in and then go to a "safe" position where it would not be affected by the sun until it was enabled by throwing a switch.  An alarm could indicate a loss of power.

That is all I have for today.

Reflector Installed - working on collector

Heating fluid tank, Copper Collector, Bell Jar, Pumps and Tubing

Rear view of dish showing actuator

Reflector on its "fence pole"

A different view

Bubble Pumps

This beauty is a 1984 patent by a really clever inventor named Sorensen from Canada.  The pump uses a hand pump to evacuate the chamber 1 to a really low pressure so the water boils at a very low temp.  When it  boils, it transports the fluid to upper chamber 1 and now since it is at a higher level, water flows down pipe 12.  This pushes hot fluid into the reservoir and displaces cold water back down into the collector. Really brilliant.  No moving parts.

More items on the way.

I purchased a55 gallon storage tank and brazed plate heat exchanger.  After much investigation, an open system in my location will not be legal or economically feasible.  I am proceeding with a water/glycol closed system and using a wort chiller heat exchanger to preheat the water before it enters my electric water heater.  Calculations show that if I can heat the 50 gallons of water/glycol to 140F and pump with a sufficient flow, I can get about 15 minutes of flow out of my water heater before the thermostat kicks on at 110F.  This method, although not as efficient, removes all the issues relating to freeze protection and backflow prevention. Parts were $100 for the exchanger and $180 for the tank (uninsulated)

Polishing & Pump Reviews

Sample of what Mother's aluminum wheel polish can do.  Left, Shiny / Right, As purchased

Here is a picture of potential pump options - three dc motors - one ac.  All are the centrifugal type meaning they have a rotating impeller.  This type of pump has a longer life than a positive displacement type of pump,  The DC pumps are submersible.  The AC pump is a circulator pump.  Costs range from $6 to $60 and powers range from  about three Watts to 30 Watts.  The 6.5 w was the most inexpensive but is not built for high temperatures.  My suspicion is that the smallest pump 1/liter per minute will provide enough flow to provide only a small increase in temperature at full sun.  I can estimate the temperature rise at an assumed flow rate.  If the temperature rise is low and the pump meets the pressure requirements, I will use the one that consumes the least energy.  I am uncertain if any of these pumps will be sufficient if  immersed in a preheat tank pressurized at 160 psi.  An advantage of the centriugal pump is that they can be placed in series and if there is a failure in one, the other can pump thru to provide a redundancy in the system.

Annual Consumption Estimations

assuming state information from http://www.eia.gov/cneaf/electricity/esr/table5.html
and annual usage of 20% from http://www.eia.gov/energyexplained/index.cfm?page=us_energy_homes

we arrive at the average annual cost per year per state:

Death Ray Reflector Pics

Photos of one of the six segments after the chrome paint.  Pretty shiny, but pretty expensive.  My cousin Bruce showed me how shiny galvanized steel ductwork becomes with some aluminum wheel polish.  I have the sample outside to see how it weathers.  It was almost as shiny as the paint for none of the cost. Don from coatofchrome.com nearly burned his leg while taking the second photo!