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Boost your air conditioner’s cooling power by blocking “heat leaks”

A basic “5,000 BTU” air conditioner can pump about 1,500 Watts of heat out of a room every hour.  To get more bang for your A/C buck, find the big ‘heat leaks’ in your room — and block them.

Your air conditioner is a pump, and what it pumps is an invisible liquid called ‘heat’.  (OK, not really, but this is a useful way to think about it.)  Your A/C unit scoops up the ‘heat liquid’ from inside the room, pumps it out through the window, and dumps it outside.  As the ‘heat liquid’ is slowly drained out of your room, the room gets cooler, you get happier, and civilized indoor life can continue.

To boost the cooling power of your A/C unit, find out what’s letting heat leak into your room, and you block the leaks.  If your room is constantly filling up with ‘heat liquid’, the pump (A/C) spends a lot more energy just keeping up with the leaks, and less energy dropping the temperature for you.  Luckily, there are (at least!) three easy things you can do:

  1. Block the daytime sunlight.  Sun flooding in through the windows also brings a flood of heat into the room.  Close the blinds, pull the drapes.  Congratulations, you’ve just closed a big, gaping hole that was pouring heat in to the room.
  2. Turn off every light you can — and replace others with LED or CFL bulbs.  If you’re running three 60-Watt lightbulbs in the same room as a basic 5,000 BTU window A/C unit, you’re using 12% of your A/C’s cooling power just to pump out the heat that the lightbulbs are bringing in! Turn off the ones you don’t need, and replace the others with modern high-efficiency LED or CFL bulbs.  Good job: you’ve just blocked another source of heat sneaking in.
  3. Unplug those electronic gizmos — or at least move the chargers to another room. Nearly everything plugged into a wall socket is leaking heat into your room.  Put your hand on each ‘wall wart’ transformer, and if any of them feel warm, you’ve found another leak through which heat is sneaking into your room!  When you unplug the gizmo, you plug another heat leak.

It’s common to find 20% or more of an A/C unit’s cooling power being used up needlessly, pumping out heat that you can easily block before it gets in.  Block that heat before it gets in, and presto: 20% boost in A/C cooling power.

 

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“Five Elements” light sculpture

After months of work, “Five Elements”, my first full light sculpture debuted this weekend at a private event.  This quick video shows a short clip of each ‘element’; the actual five-element cycle is 12 minutes long, repeating each of the five elements five times each hour.  As with any “version 1.0”, I have a dozen ways I’d like to polish and keep improving it, but I’m happy with it as is, too.

It’s illuminated by 150 RGB LEDs and controlled by an Arduino Uno using the FastSPI_LED library and my own custom code.
The installation at the debut event used a very different diffuser which made the LEDs more visible.  While both were good, I think I prefer this diffuser overall.


Small Scale Solar power presentation

I gave a “learning lunch” presentation on Small Scale Solar power today.  We had a great audience, got great questions, and had fun doing it — despite the definite lack of sunshine to play with today.

The Short Version is this:

  1. Hook a solar panel to a charge controller to a battery.  (There are starter kits with everything.)
  2. Presto: 12 Volt DC power!
  3. Use your newfound power as-is, or step down to 5v USB, or up to 120VAC using an inverter.

60 Watts of solar panels

The slides don’t tell the whole story by themselves; that requires my own personal song and dance routine.  Nevertheless, here they are, with “lite” graphics for fast download: PDF.


Ice cream no longer requires adult supervision

On the sunny afternoon of Sunday, April 29, 2012, Eleanor, Abby, and a friend, all age 9, walked half a mile to The Chilly Cow for ice cream, and then back again (with a stop at the library, of course) without adult supervision or accompaniment. Total round-trip time was slightly more than an hour, well under the contractually pre-negotiated 90 minutes.

The adventurers’ parents spent the intervening time in various degrees of distraction, ranging from mindful confidence to … less meditative states.  Overall the experience was deemed a great success all around, and at least two of the parents in question got a little choked up for a moment over the “our kids are growing up” factor.

The trip itself was a little less than a half-mile each way, as the crow walks. If you’re a grownup, or driving, or both, you might think of this particular half-mile trip something sort of like this:

Chilly Cow by car

But if you’re walking, it’s more like this (please do click the image to get the full experience) :

Chill Cow on foot

But actually, I think that if you’re 9 years old, and you’re doing this by yourself for the very first time ever, it has nothing to do with time, or space, or distance, or any kind of map at all.  It’s just pure, undiluted awesome.  And that is exactly how it was reported afterwards.


Rejuvenating solar garden lights — with nail polish!

Solar LED garden lights are everywhere these days, and by ‘everywhere’ I mean ‘in our yard.’  We’ve had some for a few years now, and simply through exposure to the elements, the plastic that covers the solar cells becomes so opaque that only a small amount of light gets to them any more.  With the solar cells deprived of even that meager light that we get in Massachusetts in the winter, the solar cells don’t recharge the battery, the battery doesn’t power the LED, the LED doesn’t light up, and our yard has a serious bling deficiency.  Eleanor and I took our solar garden lights inside to see if we could make them bright again somehow.

My first thought when confronting the frosted-over plastic was to try to ‘polish’ it with a fine-grit sandpaper.  I had 400-grit handy and tried it on one cell, the bottom one in this picture.  The top shows how weathered the cells were to start.

Solar garden lights, all 'frosted' over

The sanding helped a little.  Then I rinsed the sanded plastic dust off with water in the sink, and while it was wet it looked great, but as it dried it became frosted and opaque again.  Thinking that perhaps we could use a mild plastic solvent to ‘polish’ the rough surface, I dabbed the solar cells with acetone, but again, as soon as it dried, the surface went from clear to cloudy again.  “We need some way to keep it ‘looking wet’ even when it’s dry,” I mused.  Eleanor got a wide-eyed LIGHTBULB! look in her eyes, and grabbed a bottle of clear nail polish!  She applied a few test swatches.

Nail polish on solar cells?

The nail polish made the weathered old solar cells crystal clear again!  I held the lights while Eleanor applied an even coat of nail polish to all the solar cells.  It really didn’t matter whether the cells had been sanded or not, so we didn’t bother.

Using nail polish to rejuvinate solar cells

A few minutes later, the polish was dry, and we planted the lights outside again.  You can see how completely clear the solar cells are.  Our only concern was that the nail polish might block the UV light that provides a good portion of the solar energy to the cells.

Rejuvinated solar cells soaking up sunlight

We waited for twilight to fall, and when we checked the lights: success!

Fully-recharged solar light glowing brightly!

Even though it was mid-February the solar cells were now getting enough light to make the LEDs glow brightly!  The solar cell rejuvenation project was a total success, and once we figured out how to make the cells ‘clear’ again, it was a quick and easy.

So what did we learn? We learned that ‘frosted’ plastic reflects precious light away from the solar cells; clean, clear solar cells can capture much more light.  Clear nail polish is perfect for rejuvenating plastic-covered solar cells that have become weathered and dull. Some of the solar garden lights they sell have glass covers, and we speculated that they probably (1) are much more resistant to weathering, and (2) probably should be ‘cleaned’ differently from the plastic ones.  Sometimes you need to try one thing to find out what you need to try next.  Sometimes restating the problem out loud to someone else can give them new ideas.  During the dim, dark Massachusetts winter, having bright, cheery little lights in the yard is great.


Remixed cookie cutters

This past weekend E and I went out to the Berkshires to visit some longtime friends.  Since St. Patrick’s Day fell on Saturday, E suggested that we all make St. Patrick’s Day cookies, and decorate them.

While the dough was being assembled, we started looking through the house cookie cutter collection for  shamrocks or four-leaf clovers, but no luck.  There were all kinds of other shapes, though, and twenty minutes and a pair of needle-nose pliers later, I had remixed one small cookie cutter into a shamrock, and one large cookie cutter into a four-leaf clover.

When the dough was ready, I cut a test cookie

Looking good (enough!), we baked and then decorated the cookies.  The shamrock was a little bit on the small side, but the four-leaf clover came out respectably well!

That totally worked!

So What Did We Learn? We learned that metal cookie cutters can remixed and remade into new shapes.  We learned that the best overall shape for a cookie is “blob”, and that “blob with minor details” is the second best shape.  Fine detail doesn’t work, and remember: you’re not making stamps that will be inked and pressed onto paper: spindly tendrils of design – skinny peninsulas- don’t work.  Filigree is right out.  If you’re going to make a new shape out of an old one, pick an old one with roughly the same length perimeter.  Small old cookie cutters make for (too) small new cookie shapes.  When you start with an old cookie cutter, bend it out into a flat circle first, then work into the desired target shape.  Cookies are dangerously tasty.

-Mark


Jerk Chicken, Sugar Reef Style++

This extremely tasty jerk chicken recipe comes from the awesome and sadly now-defunct Caribbean restaurant in New York City called Sugar Reef.  It appeared in the sadly now-out-of-print Sugar Reef Caribbean Cookbook. Despite all the sadness, this recipe still makes people very happy.

The original recipe called for half the quantities of dry spices (except salt) as these, and included the note to double them for a more authentic flavor. These quantities have already been doubled (except the salt), and it’s delicious and spicy.  If you wish, you can cut the dry ingredients (except salt) in half for a more mild flavor, but if you’re looking for a more mild flavor, then what the heck are you doing cooking jerk chicken?

I’d note that the heat of peppers can vary almost as much as peoples heat tolerances; carefully taste-test your peppers and adjust the quantity accordingly.

Dry Ingredients

  • 2T ground allspice
  • 2T ground thyme
  • 3t cayenne pepper
  • 3t ground black pepper
  • 3t ground sage
  • 1.5t ground nutmeg
  • 1.5t ground cinnamon
  • 2T salt
  • 4T garlic powder
  • 2T sugar

Liquid Ingredients

  • 0.25c olive oil
  • 0.25c soy sauce
  • 0.75c white vinegar
  • 0.5c orange juice
  • juice of one lime

Chunky Ingredients

  • 1c chopped white onion
  • 3 green onions, finely chopped
  • 1 scotch bonnet, habanero, or other very hot pepper, de-seeded and finely chopped.  I’ve used more when the peppers have been too tame for my taste, and on at least one occasion, it still wasn’t enough for me.  But maybe that’s my problem.

Chicken

  • 4 chicken breasts, trimmed; 6-to-8oz ea, or at least that’s what the recipe said in the cookbook, and that’s what they served in the restaurant.  I’ve used boneless chicken thighs and been at least as happy, if not happier, with them.

Directions

  • In a large bowl, combine the dry ingredients.
  • With a wire whisk, add the liquids.
  • Add the chunky ingredients and mix well.
  • Add the chicken breasts, cover, and marinate for at least one hour, longer if possible.
  • Preheat outdoor grill.
  • Grill chicken breasts for 6 minutes each side or until fully cooked. While grilling, baste with marinade.

Alternatively, instead of grilling the breasts (or thighs) whole, you can cut the chicken into large chunks, and grill it on skewers, turning them every couple of minutes.

The original recipe ended with “Heat the leftover marinade and serve on the side for dipping,” and while I’m skeptical about serving goo that’s had raw chicken sitting in it, I think if you “heat” it all the way to a boil first, it’s probably fine.

They also say that this recipe “serves 4”, but I’ve found that if you make up the specified amount of jerk marinade, you can easily marinate twice as much chicken in it.  Put the marinade and the chicken in a heavy-duty zip-lock bag for efficient marinating.

Enjoy!

-Mark