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> Curious about SPS + A/C

The SPS is rated for 2000W, best-effort. That gets you probably one large window AC. It will run when the grid is down and the sun is shining on your panels, which depending on how your roof is angled and what trees etc there are might or might not be enough?

It will have times when it loses power due to clouds. I believe when that happens the SPS turns itself off and you need to manually re-enable it by flipping a switch in the basement. So might be a lot of hassle.

cbron Home Solar Resiliency

> Why propane? Because gasoline slowly degrades (polymerization) and needs to be drained, disposed of, and replaced with new (typically every year or so). Propane doesn't degrade over time.

If you have natural gas piped to your home then a natural gas generator is a solid option. Expensive, though.

cbron Home Solar Resiliency

> They do have models that can function off-grid, and even models with attached batteries to handle surge loads and night-time operation, but these models are not as widely installed.

Talking to solar salespeople, they say it's not code to run your house off-grid directly on the panels, without batteries. I'm not sure why; maybe they think handling brownouts is too much of a problem?

We're planning to install an SMA inverter [1] that has a "Secure Power Supply" outlet in the basement that gives best-effort power during a grid outage. This seems to be the only option on the market that gives you some power when the grid is out without needing the very large (quoted at $10k for the smallest size) expense of a battery system.

[1] https://www.sma-america.com/newsroom/current-news/news-detai...

cbron Home Solar Resiliency

> What about heat in a power outage?

Right now we'd have no heat. I'm thinking of putting together a small general purpose battery backup that we can normally charge via the wall but can also charge via the SPS on the solar system we're installing. I'd use it for whatever was highest priority; depending on time of year that could be boiler, sump pump, fans, or unexpected things.

cbron Home Solar Resiliency

I looked into this some and found some of the most useful advice was for people going to Burning Man. For example: https://www.theplayalabs.com/shopping-list-solar

My understanding is that for anything big like a fridge (even a minifridge) the efficiency and reliability of standard well-optimized 120V AC appliances means it's worth it inverting to AC instead of sticking to DC. Lots of RVs use/used 12V DC systems so things are available, they're just not very good. Inverters are very efficient these days. Plus it's really helpful to have a way to run AC things you already have if you need to.

Though if you only want lights, I do see how DC could make more sense if you can either find or DIY the right electronics to handle the voltage issues.

cbron Image EXIF Orientation Bug – or Feature?

It's unfortunate that ImageMagick decided to call their primary command "convert".

cbron Image EXIF Orientation Bug – or Feature?

1. This uses the Image Magick command "convert" so it will work on any system that has it installed. I've only used it on Mac and Linux.

2. It isn't lossless, no. I think jpegtran can do this, but you'll need to first read the correct orientation out of the EXIF data and then give the right arguments to jpegtran. Since the loss in quality is tiny, I just use -auto-orient.

cbron Why Some Gravestones Are Shaped Like Tree Stumps

I found several of these in Hollywood Cemetery in Richmond a few years ago and was confused by them: https://www.jefftk.com/p/assorted-pictures#tree-graves

cbron Image EXIF Orientation Bug – or Feature?

To fix these:

    convert -auto-orient in.jpg out.jpg

cbron Whole House Fan and Evaporative Cooler

Author here: I don't know very much about how swamp coolers are used in practice, so I could easily be missing something. I do know that they're basically never used up here in the Northeast (Boston) because they work by increasing humidity and in the summer we tend to have pretty high humidity already. We also tend to have daytime highs high enough that the air leaving a swamp cooler would be warmer than the temperature of a structure that's been cooled overnight with a whole-house fan, plus more humid, which means during the hotter parts of the day you don't want to bring in outside air. So, how could a swamp cooler be used without increasing the daytime humidity of the house?

What I'm imagining is running a swamp cooler overnight to cool the structure of the house as close to the wet bulb temperature as possible, then in the early morning run it a bit in fan-only mode to bring in drier outside air (accepting that this will warm the house up a bit), and then shut the house up and turn the cooler off for the day.

What we currently do is run a whole-house fan overnight, and shut the house up during the day, with no swamp cooler. I'm trying to figure out whether adding some evaporation to the system could make sense.

cbron A new digital divide: Young people who can’t use keyboards

Japanese isn't as well suited to a keyboard as English is; a smartphone and keyboard are about equally fast for typing Japanese.

cbron A Major Industry-Funded Alcohol Study Was Compromised

>patients are known to be highly inconsistent when reporting their own alcohol consumption. Answers patients provide depend on many factors, including the doctor-patient relationship. And patients’ spouses often disagree with their partners’ assessment of their drinking. The MACH15 trial had some sophistication built in to it, including the use of random smartphone-based check-ins for patients. But while some evidence suggests that smartphone-based self-reporting on alcohol consumption often contradicts patients hindsight reports, MACH15 had no ability to tease out which patients would adhere to the smartphone check-ins, and which were providing accurate accounts of their consumption. In essence, the NIH was making a $100 million gamble that volunteers would portray their alcohol consumption accurately.

This doesn't seem like a problem with the study design to me. You're effectively assessing the effect of telling people to drink "zero" vs "moderate" alcohol as opposed to the the effect of actually drinking those quantities, but since one major use for a study like this is to figure out what doctors should be telling people this still seems valuable.

cbron Unidentified Plane-Bae Woman’s Statement Confirms the Worst

Are they saying they were misquoted? I'm seeing them unhappy about the publicity, but that's not slander.

cbron 52-hertz whale

Where did you read that? It can't possibly be right: the Pacific alone is 160M km^2.

cbron ‘You can't use Brotli for dynamic content’ and other misconceptions

Apache has dynamic modules too, and they're generally better designed. In nginx they were added later and a module compiled against one version of nginx won't work against any other. With Apache you could download a mod_brotli binary module and use it with any (2.4) Apache build.

(I used to work on mod_pagespeed)

cbron If a pilot ejects, what is the autopilot programmed to do?

https://en.wikipedia.org/wiki/Cornfield_Bomber

https://en.wikipedia.org/wiki/1989_Belgian_MiG-23_crash

cbron The US startup is disappearing

Availability of credit over 7 years is generally much less valuable than $200k.

cbron I discovered a browser bug

Anyone can get an HTTPS cert, and with Let's Encrypt it's free. Restricting dangerous features to only websites that can demonstrate their traffic hasn't been man-in-the-middled is very different from giving established sites more expansive permissions.

(Disclosure: I work at Google, though not on browsers)

cbron The US startup is disappearing

What would keep someone from getting an economically valuable degree, declaring bankruptcy on graduating, and then just waiting until that had expired from their credit record?

cbron Linus Torvalds on aliasing

> Most of what Linus says would run foul of HN's guidelines

Keep in mind that you're much more likely to see it when he explodes at someone, because that's more entertaining to read. Most of what he writes in the ordinary work of building a kernel is unobjectionable.

cbron NTSB: Autopilot steered Tesla car toward traffic barrier before deadly crash

Poor angular resolution means you can't tell if an object is at 12 o'clock vs 1 o'clock. It means you can tell there are things, but you don't accurately know what angle they're at.

cbron Developers are manufacturing prefabricated apartment buildings

Huh? People used lead paint widely, and many 100+ year old houses were painted with it.

cbron Ask HN: Do I place the fan so that it blows air inwards or outwards?

You can also use fans to cool the environment, trading hot inside air for cooler outside air. For example https://en.wikipedia.org/wiki/Whole-house_fan

cbron Apple Avoids Amazon’s Beauty Contest, Searches Secretly for New Campus

> I'd get 3-5% higher CPM if I filtered non-US traffic.

3-5% higher CPM on how many fewer pageviews? In general, filtering out traffic should always make you less money, even as filtering to the most profitable traffic increases how much you make per page view.

If non-US traffic really were losing you money your advertising company could always drop ad requests from non-US traffic.

cbron GDPR compliance checklist

You could use an IP -> geo lookup, and block EU countries.

cbron Introducing .app, a more secure home for apps on the web

Can you give an example of a site that couldn't be moved to HTTPS? I would expect that even if the serving stack doesn't support HTTPS you could put a proxy in front of it.

cbron So Long Last /8 and Thanks For All the Allocations

ipv6 to supporting servers is about 20%: https://www.google.com/intl/en/ipv6/statistics.html

cbron The Many Ways Google Harvests Data

Every time you load a web page they can see your IP address, and IP addresses can be mapped back to rough locations. Sometimes people use "GPS" to also include things like your phone figuring out where it is based on what WiFi names it can see, but I don't think I've ever seen it for IP-based geolocation.

(Disclaimer: I'm an engineer at Google)

cbron Facebook Container for Firefox

Any site which iframes in another site where you're expected to be logged in. For example, Disqus comments, Facebook like buttons, Youtube embeds (which work, but show ads even if you've paid for no ads).

There are also lots of one-off cases where developers split functionality across multiple domains in ways that were fine at the time but now get blocked. These are all fixable, unlike the iframing case, but it's still a lot of sites.

cbron A Wyoming Creek Flows into Two Oceans (2017)

This means everywhere uphill from this creek can't be assigned to a watershed, or we can't model watersheds as a tree. My guess is water modeling software can't handle this situation.

(Cases where an elegant model covers almost everything but not quite are frustratingly common.)