View Single Post
Old 05-06-13, 10:47 AM   #26
AC_Hacker
Supreme EcoRenovator
 
AC_Hacker's Avatar
 
Join Date: Mar 2009
Location: Portland, OR
Posts: 4,004
Thanks: 303
Thanked 723 Times in 534 Posts
Default

Quote:
Originally Posted by Xringer View Post
I've been doing some hot water heating with PV for a while now...
Xringer,

I'm not sure how it is that you are applying your solar PV power to your electric water heater when you are in resistance mode?

Last time I tuned in, you had bolted a big power resistor to your old oil burner water reservoir.

Are you still doing that?

Reason I ask is that Elgo correctly pointed out that 'immersion resistance' heating was much more effective than 'surface contact resistance' heating.

In my experiments in measuring the actual efficiency of surface contact resistance heating, I got an efficiency of about 66%, and I would assume that a power resistor bolted to a water reservoir would be much worse.

Although I didn't test it, I would assume that immersion resistance heating would be closer to 100% efficient.

So, are you using a resistance heating element that is actually in contact with the water you are heating, or not?

-AC
__________________
I'm not an HVAC technician. In fact, I'm barely even a hacker...
AC_Hacker is offline   Reply With Quote