How works an electric cooler: Cell peltier

We pack a cooler for the curious

Well, after a temporadilla almost no entries, I think this summer will not you going to complain;.)We'll start with this entry, in which he disarmed a cooler of those that plug into the car (or home if you adapt one transformer least 5 amps and 12 volts), to discover another fascinating use of semiconductors (thermoelectric effect) and electricity: The Peltier cells .

Replace magnesium sacrifice anode in hot water tank by yourself

After four years working properly, it is time to do the maintenance of DHW storage tank from the solar thermal collector  changing the magnesium anode which prevents the deposition of oxide by galvanic protection .

Sacrificial anodes will last more or less depending on tank size and the degree of degradation thereof , that is; if you have many areas without paint, he's paid to oxidation and anode (magnesium in this case) will provide more ions, degrading its structure more quickly.

First of all, we acquired a couple of sacrificial anodes, are cheap, about 15 € each (I ordered them on Ebay for a company of Madrid). To change it, release the cover ( IMPORTANT empty it first ), loosen all the lime and use mud accumulated over the years:

Repair of electronic tracks on an old keyboard: Conductive silver liquid

In this post we will repair CNC keyboard that is no longer being manufactured

Contacts on the keyboards have evolved from mechanical systems to more modern with membrane. In this case we will repair an intermediate type; this keyboard from a Gemini 8050T FAGOR around 15 years old carries a screen printed aluminum membrane for tracks and graphite contacts, on which a metal piece with flexible concave shape closes the contact when pressed.

The technology of switches on keyboards usually are of two types: contact , where some kind of spring (metal or plastic or flexible rubber, etc) keeps separate tracks of the conductive surface (graphite or other) of the button, which when pressed blend tracks; and secondly, the induction, where pressing the button, a small magnet creates a small electrical pulse in the coil of the membrane (ultra durable modern musical keyboards).

Repairing first type of keyboards often requires all your ability of "handyman"; some with copper tracks like TV remotes are often easier to repair welding on the tracks a small micro-switch if the button is completely useless, but most cases are plastic membranes that can not be welded and we can use either glue threads on them as in this entry, or use the useful liquid silver, and you will always get a more professional work to build the appropriate cable connections.

Equipment needed

1. Cutter to open the damaged contact (in other keyboards will not be necessary).
2. Cleaning liquid or solvent which does not attack the material of the keyboard; I used Ardrox 9PR5 or you could use isopropyl alcohol.
3. Liquid silver conductive, with which "will draw" deleted / damaged tracks with a fine brush after cleaning them well.
4. A tester to verify that the track drawn conducts electricity.
5. Scissors, PVC tape to cover the contact again, brush, permanent marker to draw the button again, etc.

Get the most out of your SSD: Adjust Windows 7 settings

I chose the 840 Evo 250GB for its value / capacity / price

Change your computer's hard drive for an SSD ( Solid State Drive ) is the best way to rejuvenate a few years , letting you skip loading the operating system in a minute to do it in just 15 seconds ; thanks to the speed of read / write access to the programs is almost instantaneous.

Disks SSD, being immune to shock and vibration , are especially recommended for laptops, as discussed in the previous post on the subject . The best value are the Samsung and Crucial (for less than 100 € 250GB -4/06/14).

And if you use the Samsung RAPID software, get these speeds ( Source )

Replacing brake lamps in the car for LED lamps: How to Fix a bad quality LED

In a car brake lights are the most often melted by your continued use (apart from the H7 and H4 for which there is not equivalent LED), so when changing LED we reduce electricity consumption (and fuel) and especially maintenance (not usually easy to change bulbs in cars). (If you stumbled here looking for how to change them, here's the answer ).

I do not recommend installing lamps that are not approved, can be dangerous (as discussed below), unless you have knowledge of electronics can meet with burning car . 

I  bought a pair of lamps DX.com  equivalent 9W (thinking then reduce its power equivalent to 5W lumens if so, which rarely coincide with reality announced on that page), the typical 2 filaments 27 / 5W (connection T25 / T-25/1016/1034/1130/1152/1154/1157/1158/1493/2057/2357/2397/7528/3496 / BAY15D), and by placing saw that the light does not worked .

How to improve the insulation of your glass windows for very little money

Polycarbonate window insulation applied

Surely with the crisis many people can not change their simple windows to double due to budget for insulation (although there are fewer homes without this basic insulation, but any Hayles), but using imagination and available materials as we did last time we can use cellular polycarbonateand achieve a thermal and sound insulation than a double window glass for only 15 € in materials , without changing anything in the long window and when we care not to lose sight (or want to make it translucent with image faded ), and we are careful to clean it (is easily scratched).

Have been discussed in this post virtues and multiple uses of cellular polycarbonate, very appropriate because the way network makes it more resistant while creating small air chambers that increase the insulation . Here is a catalog Resopal .

Example of installing a coil into a wood stove connected to existing radiators to share the heat to the rest of the home

Your coil makes good use to be able to put the logs inside.

Julian Elizondo, Navarra, has installed a coil embedded in the wood stove with all the necessary security . He says that he works very well considering the stove all day running, get temperatures of 20 ° C throughout the house without much cane put him into the fire, partly helped by the good insulation of the house as outside usually around them 5ºC half the winter. In total has cost about 700 euros between coil, copper tubes, electronic thermostat, valve autofill, another thermal shock, trap, etc, and to install have used the same gas boiler for move water ( as I explained in this post ) and have it plugged into the nearest radiator , eliminating it. Achieve heating elements 55 60 cm (aluminum radiators) and usually kept between 43 degrees and 50 degrees most of the day, Home on since morning.

Most of the installation is done it with the instructions of a cousin who is a plumber, who was the one who installed the auto-fill valve and electronic control of temperature in the boiler. Were turning and after several sketches decided the shape of the coil to better exploit its serious fire in C , as your stove is two doors and did not want to cancel any of the two doors.

The coil steel tube with 2 mm wall. or more will last a lifetime, because as a closed circuit oxygen from water by reacting rusting steel is consumed, until they oxidize more (formerly all radiators were much cast steel wall).

Prevent the hard drive of your ultra portable to be damaged by shocks: Change it for an SSD

Top conventional disk 1.8 "; under SSD 1.8"

In this ultraportable Compaq Mini 700 10.2-inch screen was broken hard disk 4.57-cm (1.8 inches). These very compact and manageable laptops are susceptible to small bumps and tear that ultimately damage the hard drive, so you'll change your hard disk by another 80GB SSD (virtually immune to shock flash memory) for a 60GB € 60 purchased on Ebay.

In the SSD careful with the brand that you acquire (OCZ, Kingstom, Samsung etc) ; to save you can be buying one with low quality components that are damaged in a few months). They are still very expensive and low capacity  (that is changing at the speed of light ) for use on a desktop, but thanks to its low power consumption, shock resistance and high speed access will eventually imposed on notebooks .

Building a solar panel using polycarbonate base instead of glass

Cell acquired on Ebay ; 3.5W and 14.1% efficiency 100 ud. € 105 from Solar_rex

UPDATE: DON'T do this, it doesn't work more than a few months, due to the different thermal-expansion of the policarbonate film against the cells, it brokes the cells apart.

Lately he has given me to go against the government moves about , and I'll build a couple of experimental solar panels that give me hope 340 Wp. This ideal situation is never going to give, so at least I hope that normally produce about 150W with good sun, that's what I always spend a minimum and thus eliminating the cost of an appliance like a refrigerator; I estimate a saving of about 5 € per month. It's not much, but the cost of all materials as amortizaré in about 6 years, and if all goes well, will produce about 20 years.

Contrary to what you think our government (as usual), photovoltaic panels HOUSING (I am against them on land until they are more efficient than trees SETTING obtaining energy and CO2) only have advantages for that install and rest of society ; produce more than they consume and generate when it is consumed, stabilizing the system and reducing energy losses. And that that that install "take advantage of the system by eating at other times" is very subjective, and only affect the hours from 17 to 23 hours a day, and that hour the rally can be supplemented by indigenous energy Green generation from solar, very economical and available at those times hubs.

Although I'm going to do because I love the "do it yourself" and has always done me a huge illusion build me one,  usually fabricarte your own panels is not profitable , because, apart from the time required for all the preparations, they can stay bad and quickly spoil if they are not adequately insulated from moisture; no finished panels that only cost 50% more than it would cost only loose materials. Using polycarbonate base But as we are, we will break the deck and risk using insurance, economic and resistant polycarbonate instead of the usual low-iron tempered glass .

Advantages of using polycarbonate front glass photovoltaic panels :

• Economy; It is up to 4 times cheaper.
• Resistance: It is virtually unbreakable; endures all hail; 200 times more resistant than glass.
• Lightweight: Weighs approx. 3 times less than the glass.
• Security: A traditional glass module released by wind or poor subject represents a great danger to people and materials by weight and features.
• Utility: flexible, easy to work, can be drilled and cut easily.

Disadvantages of PC versus safety glass:

• Dilates 3 times more than the glass (coef. Of 65x10E-6 versus 20x10E-6 glass), so you need to choose a fastening material PC cells to absorb these thermo-mechanical stresses.
• Has less transparency; while the crystal can reach 98%, the PC is 90% (without considering that usually come treaties to reflect UV rays and longer life).
• Whitens time; 20 years transparency is reduced by 5% in those treated against UVA as Lexan that I use.

Less transparent it is not greater problem; to receive less sunlight silicon cells will produce somewhat less daily life but also extend proportionately as they can only produce a certain amount of energy before going to deteriorate more and more (as mentioned, about 25 years).

By having silicon cells PC and the motion control different thermal expansion coefficients, the choice of a material mooring cells while protecting them and to stretch along with the PC base is critical to ensure the durability of the panel and the cells. Let's see how we will dilate panels have prepared .

The expansion coefficient of polycarbonate is about 67 x 10E-6 = 0.00067. To calculate what we will dilate we must use the following formula:

Thermal deformation ( d ) depends on the coefficient of thermal expansion ( a ), element length (L) and the temperature change (DT) and can be calculated as:

d  =  a  L  D T

Therefore, the plate that will use the maximum variation that you will have are:

0.000067 * 1500 mm long * dif. temperature (about -15 to 70 ° C;. 60) =  8.5 mm.approx.

70 is in the worst case, when the summer sun tightening, as the cells become very hot and much of the heat transferred to polycarbonate. Evitarems clamps fixed everything, and if we have to drill to fix, we will have sufficient clearance for expansion; just make holes with a torn 1cm holding screw and washer grandesy rubber without tightening completely, so that the panel is subject but can "float" on the grip. 
If we do well and put too many screws while the plastic shrink and expand, it will eventually break . To pierce the solid plate drill we can use wood or iron, ensuring that the material does not get too hot while drilling (can use a little water for cooling).

Indications drilling in plaque

Using neutral silicone sealant as
the other hand, considering this, we must analyze the adhesive used to fix the cells, the first thing that came to mind was the epoxy resin and neutral silicone; speaking with a professional bouquetI opted for the neutral silicone resistance to UV light, durability, flexibility, price and especially adherence to PC . If we choose to fix the cells using neutral silicone transparent only from the reverse side, which has an excellent grip on the polycarbonate and allows the passage of light between cells, keep in mind that the cells, dilation effect PC, they will rub therewith to fray a little while emborronándolo over the years; reducing its efficiency, we must also assess put between the cell and polycarbonate, as thin as possible, for the expansion of polycarbonate, to get cooler than the cell, the end will be close to it; and 5 mm. to dilate up to that extent the PC compensate with 3 mm. maximum of each of the cell expansion; 2 mm. difference that silicone can stand perfectly.

Finally remains to determine whether the silicone chemistry we choose attacks the material of the photovoltaic cell . The information I have found is that even can replace the EVA as a sealant most effective and easy to work, such as acetone silicone Neutra, that being neutral, if we let it dry well does not have to give any problem, but time will tell as silicone used is relatively new. The transparent neutral silicone has the following advantages over other materials:

• Excellent adhesion to PC.
• Stable and resistant to UV rays to the weather.
• Wide range of operating temperatures; holds no muss from -50 to 250 ° C.
• If it is colorless, has excellent light transmission.
• Unsurpassed flexibility, up to 400% elongation.
• Repairable and easy to use.
• Economic.

To mount the first cells have to stiffen the polycarbonate , for although the cells have a bit of stretch (very little, are extremely fragile), we must prevent us twice to go to place.
To do this I will prepare in advance for the support, and I will tie him to place the cells then glued with neutral silicone colorless transparent. Os I will comment about my progress, wish me luck;).Be happy!

Sources: Calculation of deformation temperature changes of the material Use of PC analysis on PV solar cells ( mirror ) Use of silicone as PV Cell encapsulation efficiency comparative study using EVA or silicon photovoltaic (English) ( mirror ) Advantages of encapsulating gel Silicone versus EVA Polycarbonate: Their advantages over glass

Building your own High Quality CREE LED lamp with 700 lumens and spending only 6W

Mounted lamp with recycled parts

In this post we will see how to build a LED lamp for your house with 700 lumens with only 6W power consumption using 3 chips CREE XML T6  fed pure white 166 mA each (6W / 12V = 0,166A) a controller 220V with 6W 12V output power, and something like this cap , but I used a recycled sink another LED lamp 7W (thermally conductive plastic) and a fine of an old E14 energy saving lamp. Total Cost: € 18

The CREE LED chips are expensive but give much light per watt, high quality and durable, enduring the worst working conditions.

By making LEDs work well below their rated power (only 25% according to its spec sheet ) get more light per watt, while also reducing its temperature and lengthen your life until after 30,000 hours . A bulb in which the driver will break down before (10,000 hours estimated by its electrolytic capacitor life) before the LED. Furthermore the CRI (color accuracy) increases the lower the current.