Solar Home Heating: Concepts and Methods

Solar home heating systems are gaining popularity nowadays despite its high initial investment. These systems basically utilize solar radiation to provide space heating. This means that power from electrical equipment for heating space is eliminated. There are two general systems of solar space heating based on how heat is captured. These are the passive and active solar heating system.

Passive solar heating. This system requires no equipment to capture solar radiation. Its concept is similar to heat building up inside your car when it is left parked under the sun. Heat naturally accumulates inside the space. In this design, windows, walls, and floors are made to collect, store, and distribute solar energy in the form of heat in the winter and reject solar heat in the summer. It does not use mechanical and electrical devices. Passive solar buildings aim to maintain interior thermal comfort throughout the sun’s daily and annual cycles while reducing the requirement for active heating system.

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Hydroponics: Concepts and Methods

Hydroponics is one of the many methods of soilless agriculture through which plants are grown using mineral nutrient solutions in water, without soil. Many commodity crops like tomatoes, onions, lettuce and cabbage have been successfully cultivated through hydroponics, and their produce well-accepted in many markets. The theory behind the method is that the soil is only a mineral nutrient reservoir and hence, it is not very essential to plant growth. The mineral nutrient can be introduced into a plant’s water supply artificially which is then readily absorbed by the plant’s root. The concept of hydroponics is significant in today’s world as it contributes to the growing concern for steadier food supply, as well as the reduction of suitable arable land for agriculture.

 

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Solar Lighting: Concepts and Methods

Households usually use fluorescent lamps, and even incandescent bulbs for some, as a source of lighting. These devices consume so much electrical energy which is sadly a great strain to the bills of household owners. However, lighting can be achieved naturally instead of using electrical lamps. We can utilize a free and abundant source – the sunlight. (image source)

Solar lighting is a method of harnessing the light from the sun to provide illumination to a space. Sunlight is collected and distributed throughout an area using specialized equipment or through the structural design itself. It implies wise selection of window types, sizes and orientation. The energy-saving idea is very useful in places receiving ample sunlight since no electricity is utilized to light up a space during the day. Individual features include clerestory windows, skylights and light tubes.

How to Perform Statistical Computations using Microsoft Excel: Basic Statistics

Statistics is all about data, particularly those quantitative information and even qualitative facts converted to numerical equivalents. So what is being done with these data? After collecting and organizing them, we summarize and present them in a simplified and compressed form that is easy to understand and discern. The much harder task is the interpretation of the results and of the summary you have made.

With regards to summarizing and presenting statistical data, the key activities are computation and creation of charts or tabular presentations. We can do it manually or using calculators. But with the bulk of data that you may have, such work would be difficult. However, Microsoft Excel can do the job with an eyes’ blink. It is a software program common to almost every computer and hence, this simple step-by-step tutorial can be followed by anyone.

In statistics, one way of summarizing data is to compute for the measures of central tendency (such as mean, median, and mode) and the measures of variation (such as standard deviation and variance). Here is a quick guide to computing them using Microsoft Excel.

                                                                                       

How to Organize Desktop Icons and Files: Using Fences

I have previously presented the basic way of organizing your files and desktop icons (see How to Organize Desktop Icons and Files: Creating Folders and Subfolders). Another way of doing this is using the software program Fences. This is a freeware and anyone can easily find this on Google search engine and then download it for free. As for me, I found this program at FileHippo which is one of my favorite sites in the Internet since I can easily download freeware and trial versions in this site (see Free Downloads at FileHippo).

Fences is a great program for those having problems with their desktop environment. It is an add-on to your desktop and its functionality is very indispensable. So what does Fences do? How can you organize your desktop using this program? What are its unique features?

How to Organize Desktop Icons and Files: Creating Main Folders and Subfolders

Documents placed everywhere. Irrelevant program icons found on the desktop. Most used programs not seen immediately. Files missing. Files here, there, and everywhere. Do you know what this means? An unorganized desktop environment.

We all commit this techie crime of just saving files, whether documents, pictures, or program icons, in our computer desktop. For obvious reason, we want to gain instant access to them. But over time, we find ourselves deleting some of them to accommodate newer files. If we do not wish to throw them into the Recycle bin, we simply drag or cut and paste them into different folders in our drives. And when we realize we want to see these files again, we find ourselves in deep trouble. We browse through countless folders with names very similar to one another, wishing to locate them so soon. We can use the Search option, but do we still remember the file name? Soon, we find ourselves screaming, OMG!

Marvelous Animal Robots II

Animals have certain unique abilities that humans cannot do. These abilities have been proven to be of valuable use to everyday human activities. Hence, human duplicates them by creating robots. Over the years, several robots have been designed and fabricated by engineers, scientists, and researchers. I have previously featured three amazing animal robots (see Marvelous Animal Robots). Here is the second list of three marvelous and awe-inspiring animal robots.

AirJelly

The AirJelly is the first indoor flight object with peristaltic drive. It is created by the German firm Festo. The robot is similar to the AquaJelly, another creation of the company. Unlike the AquaJelly, the AirJelly swims through the air, instead in the water. Its head and entire body is a huge ballonet filled with helium, making it float on air. The diameter of the ballonet is 1.35 meters, yielding a volume of 1.3 cubic meters of helium. For it to be lifted, the robot is at least 1.3 kilograms. (image source)

The AirJelly is equipped with a central electric drive unit and an intelligent, adaptive mechanism. It is moved by two lithium-ion polymer batteries connected to the central electric drive unit. From here, power is transmitted to a bevel gear which is connected to eight spur gears that move the eight tentacles of the jellyfish via cranks. The movement created in the tentacles, called as peristaltic motion, propels the ballonet forward. The movement or propulsion based on the principle of recoil is a new concept. This is what moves the AirJelly through the air.

SmartBird

One of the latest creations from Festo is the SmartBird. This is a great breakthrough in man’s efforts to decipher the flight of birds. The SmartBird is an ultralight but powerful flight model with excellent aerodynamic qualities and agility. It weighs only 450 g (15.87 oz) and has a wingspan of 1.96 m (6.4 ft). (image source)

 

Inspired by the herring gull, the SmartBird can start, fly and land autonomously. Its wings beat up and down, as well as twist at specific angles. The mechanism employed is an active articulated torsional drive unit combined with a complex control system. Its direction is controlled by the interaction of the electric motors found in its head and torso sections. Like that in true birds, the SmartBird’s tail produces lift and functions as both pitch elevator and yaw rudder. The battery, engine and transmission, crank transmission, and control and regulation electronics are also found inside the robot’s torso.

Genibo

Genibo is a robotic dog created by the Korean company of Dasarobot of Dasatech. It is similar in concept to Sony’s Aibo. It stands a foot tall and weighs 3.3 pounds. It is equipped with sensors, camera, and voice commands which enable it to identify itself and share “feeling” with its users.  It is capable of understanding over 100 voice commands such as “sit”, “roll over”, and “come here.” It can also change its mood according to user interaction, such as happiness, sadness, anger, and sleepiness. (image source)

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Ten Major Advantages of Briquettes

Fuel has always been an indispensible need of man. Whether from developed or third world countries, people around the world need fuel for everyday living. In preparing our basic necessities like food and clean water, we need fuel. Usually, we rely on electricity and fossil fuel (like liquefied petroleum gas and kerosene) for our energy need.  Some nationalities use firewood and charcoal. However, there are other resources which have more advantages and benefits that these conventional sources. One such fuel is the briquette.

Briquettes are flammable blocks of matter used as fuel. They are made from extruded or compressed shredded combustible materials. A binding agent like starch may be necessary to hold the materials together, though pressure may at times be enough. Some of the common materials used as briquettes are charcoal fines, mineral char, sawdust, chaff from rice, peanut and other crops, peat, and any biomass materials.

So why do we have to used briquettes instead of firewood, charcoal, or electricity? What are their advantages over them? Well, here are ten of the major benefits derived from the utilization of briquettes as fuel.

1. Concentrated. Since briquettes are created from compressing combustible materials, they are denser, harder, and more compact. They have high specific density (1200kg/m³) and bulk density (800kg/m³) compared to 60 to 180 kg/m³ of loose bio mass. Thus, they offer a more concentrated form of energy than firewood or charcoal.

2. Slow-burning. The compression process allows the briquettes to burn for a lot longer than if it was loose in its original condition.

3. More efficient. Along with the compactness of the briquettes is the increase in heating value. Briquettes can relatively produce more intense heat than other fuel. They have a higher practical thermal value and much lower ash content (2-10% compare to 20-40% in coal). In fact, they are 40% more efficient, as well as hotter and longer lasting than firewood. This greater efficiency can be attributed to their low moisture and density.

4. Smokeless. This is a unique property of briquettes. Using them creates no smoke, soot, or carbon deposits. Depending on the base material, they produce no or little fly ash. Further, briquettes do not emit gases or any toxic chemicals like sulfur.

5. Availability. Biomass is the main component in producing briquettes. So where do we get this biomass? Look around you, and there are loads of biomass materials here, there, and everywhere.

6. Easy to make. There are presently commercial briquettes sold in the market. However, ordinary households can produce briquettes. You must only have a stock of combustible matter, a binder, and a molder to shape the briquettes.

7. Easily stored. The size and shape of briquettes make them easily be stored. We can readily pile them in several heaps because of their fun shapes like cubical, spherical, cylindrical, or rectangular blocks. They are likewise clean to handle and be packed into bags.

8. Easily transported. Compacting biomass waste into briquettes reduces the volume by 10 times, making it much easier to store and transport than loose biomass waste. Considering their shape, size, and density, briquettes are excellent for long distance transport. Likewise, loading and unloading cost are much less and are done easier.

9. Cheaper. Since briquettes can be domestically made from plants and animal wastes, they are consequently less expensive to produce, and thereby sold at lower prices.

10. Renewable. Briquettes make use of organic materials which are common and renewable. Hence, we are ensured of the sustainability of such fuel source.

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How to Solarize Soil

 

One of the natural methods of controlling soilborne diseases, pathogens and weeds in gardens is soil solarization. This technique has been used by many farmers around the world because of its adaptability to any location and soil condition. It has been proven effective and it lessens farmers’ and growers’ reliance on synthetic pesticides and herbicides. (See Soil Solarization: Concept and Benefits)

Soil solarization is done by capturing and trapping the sun’s heat with the use of a tarp or covering. After some time, soil temperature can rise as high as 125 degrees Fahrenheit (52 deg. Celsius) at the top 6 inches (15 cm), and even to 100 deg. Fahrenheit at a depth of 18 inches. Over several weeks, that is hot enough to kill a wide range of soil inhabiting pests such as wilt and root rot fungi, root knot nematodes and noxious weed seed. It takes about four to six weeks of sunny weather to sterilize the soil. The method can be done on any size of plot, as long as the plastic covering is enough to wrap the whole plot.

For a more detailed procedure of the process, here are the quick and easy steps:

1. Prepare the soil. After tilling the land, thoroughly clean the plot from any unwanted materials and debris. Pull out the weeds or residues from previous cropping. Rake the surface smooth. A fine soil surface will allow the plastic covering to be placed in close contact with the soil Remove stones and large dirt clods which may create air pockets inside the covering and eventually cause uneven heating.

2. Water the plot. The soil should be moistened if dry, but not saturated. You can leave the sprinkler on for several hours or overnight to soak the soil. Wet soil conducts heat better that dry soil. Also, there will be 100% humidity inside the covering which acts with heat to eliminate pathogens and weeds.

3. Dig a trench all around the bed or plot 6-8 inches deep.

4. Lay a clear plastic covering, around 3-6 mm thick deep, over the plot. See to it that the sheet overlaps the trench on all sides. Fill in the trench (you may even place heavy objects on the edges) to weigh down the plastic while pulling it as tight as possible.

Many people always recommend using clear plastic because the idea is that clear plastic produces higher temperatures faster because the sunlight passes through the clear plastic to heat the soil. However, for cooler climate or cooler time of the year, you may use black plastic because it absorbs the heat, making it even hotter.

 

Polyethylene plastic 1 mil thick is the most efficient and economical for soil heating. However, it is easier to rip or puncture and is less able to withstand high winds than thicker plastic. Users in windy areas may prefer to use plastic 1 1/2 to 2 mils thick. If holes or tears occur in the plastic, they should be patched with clear patching tape or duct tape. Thick transparent plastic (4 to 6 mils) reflects more solar energy than does thinner plastic (1 to 2 mils) and results in slightly lower temperatures.

5. Relax, wait, and see. You are done now with setting up and what needs to be done is nothing but wait for the effect. A few weeks of sunshine can effectively improve your soil conditions. In areas where weather conditions are generally cooler or where there are more cloudy days, or when you do not feel like waiting for a long time, you can speed up the process by adding another layer of covering. See to it that the second sheet of plastic cover is raised over ground level so that there is airspace between the two sheets. The airspace serves a buffer zone during cloudy or cooler days. The combination can also raise the soil temperature an additional 6 deg. Fahrenheit.

Source:

Wikipedia.com

Gardenguides.com

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Solar Cooker: Types and Principles of Operation

With the continuous rise in the prices of basic commodities and the increasing threat posed by the use of fossil fuel, the need to harness free and renewable energy has gained much prominence. A very promising source of such energy is the sun which virtually cost nothing and pollution-free. One of the best technologies derived from the utilization of solar energy is the solar cooker.

A solar cooker, also known as solar oven, is a device that uses heat by concentrating or intensifying the heat from sunlight. Solar cookers are generally used for cooking, drying, and pasteurization, and are a form of outdoor cooking where sunlight is available. Many organizations are advocating on the use of such device, which is usually low-cost, because it helps slow down deforestation rate as gathering of firewood for cooking is avoided.

There are several types of solar cookers based on design. There are least 65 major designs and hundreds of variations of them. They differ on the mechanism of collecting and reflecting sunlight, but the principles of operation are similar. All these devices must be able to do perform three basic functions: to concentrate sunlight, to convert light to heat, and to trap heat. Reflective mirrors of polished glass, metal, or metalized film are used to concentrate sunlight to a small cooking area, thereby increasing the heat power. On the inside of the solar cooker, a black surface which is low in emissivity is provided to further improve the conversion of light to heat. Lastly, a sealed glass cover or related mechanism is used to trap hot air inside the solar cooker. With these factors considered, solar cookers can effectively work.

Some of the more common types of solar cookers are the following:

• Box Cooker

 

This is the simplest cooker which is first built in 1767 by Horace de Saussure. A basic box cooker consists of an insulated container with a transparent lid normally made of glass or plastic. The lid can be removed to allow dark pots containing food to be placed inside. The box cooker can work effectively with partially overcast skies and will typically reach temperatures of 90 – 150^OC. (image source)

• Panel Cooker 

The panel cooker uses a reflective panel to direct sunlight onto an insulated container, usually enclosed in a clear plastic bag. A very common model of this type of solar cooker is the CooKit developed in 1994 by Solar Cookers International. The CooKit is made of aluminum pasted on a corrugated cardboard which is cut and folded to shape. It is lightweight and when folded for storage only measures about three feet by four feet. In general, panel cookers can reach temperatures comparable to box cookers. (image source)

• Reflector Cooker

The reflector cooker uses various concentrating geometries (dish, trough, Fresnel mirrors) to focus light on a cooking container. These cookers reach temperatures of 315 °C and above but require direct light to function properly and must be repositioned to track the Sun.

           

a.      Solar Kettle

One example of a reflector cooker is the solar kettle. Solar kettles, used to heat water to boiling point, can generate temperatures as high as 220^OC. (image source)

b.      Parabolic Solar Cooker

This technology uses parabolic reflectors to concentrate sunlight. Its design is somewhat complex and difficult to fabricate. It also requires more precision to focus sunlight on the cooking vessel. Hence, the cooker must be frequently adjusted to catch sunlight and supervised for safe operation. Accordingly, it has the fastest cooking time for all cookers. (image source)

c.       Cookers with Spherical Reflectors

The Solar Bowl in Auroville, India is this type of technology. Its spherical reflector focuses light along a line perpendicular to the sphere’s surface and a computer control system moves the receiver to intersect this line. It can reach temperatures up to 150^OC. (image source)

• Hybrid Cooker

The hybrid cooker integrates conventional electrical heating elements in its layout for used during cloudy days or night time.

 

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