Got my first solar shower last night

[OperaHouse]

This is doing it the hard way.  Finally got around to plumbing the water heater so we can use excess solar power to heat water.  We both had a hot shower last night with some to spare and the next day she had enough hot water at 2pm to do the dishes running out near the end.  I was given this 10 gallon 2000W 120V 7.2 ohm heater and will use it to dump excess power from the 810W of panels I use to run the chest fridge.  Yesterday was the proof of concept run.  I have three groups of panels.  The one for the test was 345W total.  From that 140W at 32V actually goes to the water heater.  Quite pleased that from 10am to 5:30pm was enough time at that power level to heat the water.  The fridge typically runs from 100-220 minutes a day and durring that time I don't heat water.  If you have followed my UNO fridge project, that program is actually called waterheater.  The fridge uses only a car battery to provide surge at startup.  The fridge only runs durring the day when the panels are active.  I store cold in liquid mass instead of power in a battery bank.  Panels are sized so the system can run on a really cloudy rainy day.  That means most days I have power to spare.  When I finish the power controller, voltage to the water heater element should be around 40V to give me about 220W.  Once I super insulate this water heater that should be enough for normal use.  Next will be another water heater for the laundry.   Having a micro controller makes diverting loads easy. 

Plumbing is a little interesting. I have an under 10 gal propane water heater that I only run when needed. The solar water heater is plumbed into the cold water line of the shower.  That allows me to use either heater.

[Bruce S]

I'm curious about the cold mass, do you make use of ICE water as the mass or have you gone the route of the ICE blankets or the igloo freezer items they have.

Bruce S

[OperaHouse]

Actually, just large amounts of soft drinks like 35 cans.  The set temp is about 35 degrees.  The temp read may go as low as 31 at the end of the 13 minute timed operation.  In the lower portions of the freezer the milk may have a few ice crystals.  Really just a large mass of cold liquid.  In the morning temp will be about 38-39.  The fridge will start as early as 7:30am.  You have to make sure that you don't add anything massive to the fridge afer 2pm.  Adding a 5L bag of wine adds about 50 minutes to the daily run time.

[nickskethisnikske]

nice to see you don't have to use a big battery bank for a solar project, but isn't it a weast of your solar energy to just heat water? I think PV panels are more expensive than those water heatingpanels. 

[tecker]

Pre heat the water or recirculating with a pump through a solar collector gives an added dimension . 10 gal is a good size to work with .

[OperaHouse]

It started out with a 12V Norcold RV fridge and two 75W Photowatt panels.  That didn't work.  Added more panels and that didn't work.  Then went with a chest freezer and analog controls and more panels.  That worked quite well except I now had too much power.  Add a lot of warm stuff on a sunny day and it would do a hot restart and the inverter would shut down.  Now with computer control the system is smart enough to send excess power to where it can be used.  This micro is controlling more than fridge and the water heater.  It also controls pumps and is the charge regulator. This is only a camp for a few months each year and the panels are pulled in.  No battery would last.  As it is I just use the battery out of the vehicle I dont take.   So heating water does make it useful.  I have an old Arista washing machine that I will control with another micro some day.   Put cloths in and some hours later it will be done.  It will talk with everything else and decide when is the best time to divert energy from everything else and do a spin cycle for 15 minutes.  Waste of power?   Lets be honest guys.  As a lot, the people on fieldlines waste far more energy than the average housewife on the grid in Sheboygan.

If I had to do it again I would have been better off buying a propane fridge.

[ghurd]

The solar water heater is plumbed into the cold water line of the shower.  That allows me to use either heater.

Cool idea.  (LOL)
I never heard of doing it that way before.  Makes perfect sense.
G-