kitchen table math, the sequel: that was quick

Tuesday, November 13, 2012

that was quick

Finally emerging from Hurricane Sandy discombobulation to discover that Poof: the semester is gone. I have just four classes left to teach (the rest being committed to in-class papers & the exit exam).


So where were we?

While I'm figuring that out, here are my current off-topic preoccupations, in case anyone has info and/or reading recommendations:

How do power grids work? (Allison posted some links on decrepit infrastructure, I think.)

What is a hurricane? What is a Nor'easter? What is a midlatitude trough? (And do other places have hurricanes followed immediately by 6 inches of snow?)

How long can you store gasoline?

Generator or inverter, or generator and inverter?

Does my fireplace produce a net loss in heat? (Do all fireplaces produce a net loss in heat? Does it matter?)

What I Saved from the Flood 

What is an IP address, anyway, and how does the FBI find out what your is if they really want to know? Also, what is metadata?


Anonymous said...

Read this:

before you get a generator.

What is your plan to keep the thing ready to work when you need it? The good news for you is that the natural disasters you get tend to be predictable, so you can test the thing before you need it.

But still ...

-Mark Roulo

kcab said...

I don't know if the fireplace is a net loss, but get the chimney cleaned if you're going to use it after a long spell of not using it.

ChemProf's spouse said...

Gasoline: With STA-BIL a year, year and a half. Depends on how much you add. There are directions on the side. You can get more expensive/industrial/specialized chemicals to make it last as long as 5 years.

Note that generators can also run off of things like propane. If you live in the kind of area where a propane tank wouldn't be weird that's an option.

Generator versus inverter: Ideally and. If you have a generator and a small inverter/battery setup it lets you just run the generator a couple of hours a day and power smaller things off the inverter the rest of the time. So if you need to charge a battery or something you would use the inverter.

Fireplace: Depends on your assumptions. If you have a working furnace and run the fireplace it will probably suck more warm air out of the house than it replaces. If you have no other heat and you have an oldish fireplace that actually was designed to be functional it'll kick a surprising amount of house back into the house. You can also cook with it if you know what you're doing.

An IP address identifies every computer on the Internet. Most people as a practical matter don't have a static IP address, they have a dynamic one. So when you connect through your service provider they assign one out of a pool. If somebody has your IP address and a time it was used and a warrant they can get your service provider to tell them who you are.

Metadata is data that's part of a file that usually doesn't display. With a photo the metadata might include the type of camera that took it, if the flash was on, what the settings were. The header part of an email could arguably be described as metadata. Most email programs have some option like "show full headers" that will show information that usually wouldn't display, which might include the IP address of the sender depending on which service they used.

Allison said...

other things to consider when learning how to take care of yourself:
if you have an old home, a great way to turn your fireplace from an airconditioner into a heater is with a wood burning insert. don't let the chimney sweeps extort you. you'll then have a backup source of heat when the power goes out.

next: water: how do you get water into your home? who is responsible for that water pumping? how is that water fed to you--if the power fails, will it continue to work, and for how long? do you have a septic system that requires water in order for it to flush a toilet? if you have a pump, or your local neighborhood relies on a pump, what's the backup plan for keeping that pump powered? generators can be rigged to provide power, but that's not something to learn to do AFTER the power is out.

How do you keep your basement from flooding? if you need a sump pump, then how will you keep the sump pump powered if you lose power?

Allison said...

Allison said...

a simple introduction to what's lousy about most fireplaces:
We like to put woodburning fireplaces into one of three categories: really good heaters, pretty good heaters and air conditioners.

The air conditioners are characterized by pulling more air out of the house than they give back in heat so their net effect on the house as a system is to cool it. Glass doors are usually an option rather than a standard feature and they are not gasketed or sealed, nor should they be closed when the unit is burning. The optional outside air will not provide more than a quarter of the combustion air needs.

The pretty good heaters are a big step up in terms of heating ability. They will generally have sealed, gasketed doors and outside air sufficient to provide all combustion air needs. They are not E.P.A. certified. As exempt units, you cannot control the heat output other than by the fuel load.

The primary difference between the pretty good and really good heaters is that the latter are E.P.A. certified. What that means to you is that you can control the combustion air intake, thereby controlling the heat output and, consequently, the burn time...

...The Cure for the Common Fireplace
From the late 1700’s fireplaces heated homes inefficiently. Some of them, such as most masonry (brick) fireplaces, are still this way. The flue of a masonry fireplace allows warm indoor air to escape up the chimney with poor fitting, warped, unclosed or missing dampers. Or in negative pressure situations such as basements and lower levels these fireplaces become a continuous source of cold air infiltration. When they burn, conventional masonry fireplaces throw nearly 90 percent of the heat they generate up the flue. Since they use nearly 300 to 500 cubic feet of air to support combustion, they actually remove more heat than they supply. They create about 400 grams of particulate per hour.

..Is wanting a fireplace making us ignore long term costs and energy waste? It doesn’t have to as there are solutions for these inefficiencies. They are called inserts. Wood burning inserts can cut the air changes to 30 to 50 cubic feet of air while returning nearly 70 percent of the heat and reducing emissions to 4 grams per hour. While a single charge of wood (4 to 6 split logs) in a fireplace last about 45 minutes, that same load will burn at least 2 ½ hours. You can also control the heat out put from the insert by slowing the air intake and the consequent heat production and make your fire last up to 8 hours.

A wood burning fireplace insert is essentially a stove without legs. It has a convective jacket that directs its radiant energy back into the room, sometimes with a fan assist. We have inserts constructed of steel, cast iron, steel with cast fronts, and soapstone lined cast units. The construction doesn’t affect the efficiency which is around 70%, but does change the rate of heat transfer. These inserts range in their heating capability from 800 to 2000 square feet depending on the cubic capacity of the firebox.

GoogleMaster said...

I live on the Gulf Coast and in the past 30 years have experienced:
- the aftermath of a category 3 hurricane direct hit in August 1983 (I arrived the day after the hurricane struck so I got to experience a major city without power, but not the hurricane itself)
- a tropical storm (June 2001) that sat overhead for a few days, wandered off, and returned to sit overhead for a few more days, dumping over 3 feet of rain in my neighborhood
- numerous other minor storms and tropical storms that flood the roads to a depth of a foot or more for a day or so
- a constant stream of news coverage during and after Katrina (August 2005) (relevant for next item)
- the panic of 3+ million people a month after Katrina when they thought Rita was going to make a direct hit on Houston, [the panic] causing 24-hour gridlock on several major radial highways leaving the city
- 8 days of no power in 100+ degree heat and 90+% humidity after Ike (September 2008), observing the neighbors across the street watching TV because their side of the street lost power for only a few minutes. Unlike you, I live in the middle of the city, not in an outlying township or suburb, and we were still without power for eight days.

I have owned my home for 20 of those 30 years. I do not have a generator, and will not buy a generator. I do, however, own a chainsaw, which we bought the week before Rita but didn't use until Ike three years later. We have since used the chainsaw a few other times for routine tree-trimming activities.

A generator is an expensive proposition, especially once you add the inverter and the cost of its installation. And how often will you need it? If you think you will be going without power for more than a few days at a time on multiple occasions, then yeah, maybe you should get one, but if it's just a reaction to your recent horrible experiences to a once-in-a-lifetime storm, then maybe not.

My recommendation: If you have any trees on your property at all, or nearby, a chainsaw will get a heck of a lot more use than a generator.

P.S. This is my all time favorite TS Allison picture, of a kayaker serenely boating down a flooded sunken freeway. The water is between 13 and 15 feet deep here, less than a mile from my house (but the same sunkenness that causes the freeway to be flooded also helps keep the water out of our homes). Taken from:

palisadesk said...

How do you keep your basement from flooding? if you need a sump pump, then how will you keep the sump pump powered if you lose power?

When the massive blackout of 2003 happened, it was precisely the sump pump issue that had me in a panic. I have two, one at each end of the house, as the water table is high where I live (near a swamp) and the sumps pump out regularly even in dry weather. In rainy conditions they go non-stop, or nearly so. If they break down the basement will be flooded to knee-depth within hours.Yikes!

Fortunately, the blackout occurred in August – no worries about freezing to death – and it was a dry summer and power was back on within 24 hours as I recall. However, after that I got a new sump system: each sump pit has two sump pumps, one with battery backup. A switching device alternates the pumping action between the battery-backup sump and the “regular” one (the plumber explained that if the other pump were not in regular use, you would not be able to depend upon it in an emergency). The battery backup is good for about 14 hours – that sounded like not much to me, until the plumber explained that was 14 hours of *pumping* time. Since the pump only runs for 11-12 seconds each time it pumps out, 14 hours would carry me through several days, possibly weeks, at least. There are lights on the unit that alert you to any possible problems and it sounds an alarm if the sump pump stops working.

I don’t recall the cost precisely but is wasn’t unreasonable and it certainly beat having a flooded basement.

From time to time I’ve considered the possibility of a generator, but SteveH’s observation rings true: the power does not go down for long very often. I was prepared for it this time (my local circuit seems to go down in any heavy weather) and had batteries, water and suchlike on hand, but did not lose power at all, though many surrounding areas did. I’m not sure that I really *need* a generator but am glad to learn of some of the factors to consider.

Anne Dwyer said...

We have a generator after losing the power for 7 days in an ice storm. We have a very high water table so if we lose power, we flood the basement.

So we had an electrician wire up switches. We plug in the dedicated plug from the generator, start up the generator and flip the switches. It runs the whole house (except power hungry stuff like the oven and air conditioning). We have used it many times over the years and it is great, especially in the winter.

We also have a water powered back up for the sump. It runs on city water. If the power goes out when we are not home, that will kick until we can get home and put on the generator.

ChemProf said...

Also note there are generators and generators. We have a small unit, which includes the invertor, which isn't wired into the house. It is basically equivalent to a single electrical outlet, so would let us charge things and run the refrigerator. That kind of unit is more reliable and requires less maintenance (especially if you go with Honda) but won't run your house.

GoogleMaster said...

Just a safety note:

Please do not run your generator inside your garage, shed, basement, carport, or other enclosed or semi-enclosed space.

Another safety tip: downed power lines can kill.

Another safety tip: falling tree limbs can kill, too.

It seems that every major storm that brings power outage, we have someone who dies of CO poisoning (i.e. lack of oxygen) because they ran their generator inside their garage. Or dies from being hit by a falling tree limb while clearing the downed trees from their property.

Electrocution, not so much, except that we've had two copper thieves get fried in the past couple months when they cut into live power lines to steal the copper. Darwin wins again!

ChemProf said...

And since, as GoogleMaster rightly says, you need to run even a small generator outside, make sure you have outdoor-rated waterproof extension cords or that power won't do you any good.

GoogleMaster said...

Coincidentally, a link to a reconstituted AP commentary showed up in today's local blogspaper.

Subject line: Power outage time after Sandy not extraordinary.

Short version: "Hey, y'all should feel lucky you were only dark and cold for two weeks! That's better than average!"