Monthly Archives: December 2011

On solar hot water via PVs and hot-water heat pumps

(1) Hi Hal:
The Geyser is 60dBA according to my radio shack meter at 3ft away from the back/fan side. But it also makes a much longer 2-sec rumble when it first starts up. Across the room it is 50 dBA.

(2) Hi Marc:
> Eric [sic], how do you have the Geyser piped – through the cold water dip tube?

hot water from the geyser circulates back to a T in the cold water supply to the marathon

colder water returning to the geyser comes from the bottom of the marathon.

This is as suggested for marathons in the geyser 6000-3.0 manual on pg 16

> And what are your solar calcs?

We upsized our PV from 200W panels to 230W (6KW->6.9) so 0.9 peak KW was a $5400 expense and gets us approximately 0.9*1200 = 1100KWh a year to use for hot water heating.

We use ~26 gallons of hot water per day according to my meter. Assuming heating from 50F to 120F that is 8.3lbs/gal * 26gal * 70F * 365days = 5.5 million BTUs/year => 1611 KWh/year. But… that is assuming straight resistance and not the HW heat pump. So… taking that into account… the geyser is “free” in the summer when the AC is on (and I’m not sure how the math works in the winter with geyser+extra basement heating… but even if it’s COP=1 we are still doing well in a annual/net sense vs the 1100KWh from the PVs.

I welcome match corrections of course!

> Do you have gallons and kWh measured into the tank, including > the resistance elements? Note that my set-up gives up the
> lower element.

We keep the resistance elements off at the breaker except when we have a predicted perfect storm of 3+ kid baths coming up.

I haven’t connected the flow meter to a hobo yet — just manually record the numbers once in a while. We have an eMonitor tracking the KWh of the geyser, but of course the basement also needs extra heat (from our mitsu air-source heat pump) in the winter because of it.

(3) RE: showerheads:
We like our Bricor B100 Max showerhead

And I often leave the kids bath water to cool off before draining the tub.


From my comment at:

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Filed under erik-green, solar

“Enough with the apps already”

I think Dave Winer will be proven right on this. Apps will die. The web will live. Why? Because of linking. LINK

And perhaps the ease of making mobile-friendly web pages and “responsive web design”, even websites which act just like a native app on the iPhones or Androids of the world — have you seen in a Chrome browser?

Just about the only thing which will stay apps are video games since linking is not (or at least, less) important in a game since games are usually self-contained universes. And even there I might be a little wrong.

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Filed under android, apple, predictions, tech, video games

Watch as Erik predits the future!

1. big 10″ ipad and “samsung galaxy tab 10.1″ sized tablets are a temporary/transition technology because…

– 1.1 no decent input. Note taking apps like Dan Bricklin’s Note Taker HD will work on this but can’t beat a keyboard and mouse. I think Bill Gates was right about that.

– 1.2 too big too carry around and not that great for watching movies in lap (laptop way more comfortable)

– 1.3 not that great for gaming since no controller! multiple kids I’ve spoken to have fully admitted this is a problem. In their words… “the games on the iPod Touch are not “rageable” — meaning I think that you can’t really get very worked up about them one way or the other because well… they are not very good. At least in a Mario Brothers sort of way. Angry Birds ok. Puzzles ok. But to really get into a game, i think one needs a controller or a keyboard and mouse. touching alone is not right. Not the right feel.

– 1.4 while it might be acceptable to pull out an iPhone and glance at it while with friends somewhere, the size of the tablets will mean that this will probably never feel quite as acceptable.
Maybe I am wrong. ala a shifting baseline of culturally acceptable things…

2. ultrapads like the MacBook Air and other windows based SSD laptops will become more popular (many of the advantages of a tablet with fewer downsides)

3. And smaller 7″ tablets will get higher-res more readable screens and

4. also android will be market leader vs ipad so all the apps that are “iPad only” right now will get fewer and fewer. Yes, I know some will remain like BBEdit, etc. But most will be available on both.

5. small phone-sized smart devices will continue to be very important. The size is right. Not too big so it fits in a pocket VERY easily. Even a little bigger than an iPhone is too big.

6. those ultrapad computers will get:

– 6.1 touch screens (there are tablet computers I’ve seen from dell and lenovo)

– 6.2 computers will also get better about having different “views” I will call them for a lack of a better word. You might have an “office” view, a “media center” view. And an “app” view.
In other words, I want to keep all the power of the platform and input devices, but I want to customize things at the “OS” level more. I shouldn’t have to install “Easy Peasy” to get a simplified laptop. It should just be another “view”. I think Microsoft and Apple know this. MacOS will probably merge (at least design wise) with iOS. I have read that it is happening already with Lion with the default behavior of the mouse in some apps. Scrolling vs Swiping…

When I want to use a computer to read a newspaper or watch youtube, it doesn’t mean it has to look like a normal newspaper website. For instance, the NY Times Chrome App is great.

7. Meanwhile, it would be nice if we didn’t have to thow out so many electronic gadgets to “evolve”. Got that “Palm V” still? That “iPod Classic”? That’s another advantage to good-ole computers. I can have a quite old piece of Windows- or Mac-based computer hardware running pretty much brand new software. Sweet.

8. A lot more people should be telecommuting given the technology we have!

We shall see… we shall see… Wake me up in 20 years!

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