Earthquakes are the phenomena experienced during sudden movements of the Earth’s crust. Under the Earth’s crust lies the asthenosphere, the upper part of the mantle composed of liquid rock. The plates of the Earth’s crust essentially “float” on top of this layer, and can be forced to shift as the upwelling molten material below moves. As the plates shift (and thus interact with each other), an enormous amount of energy is released in the form of waves. Although they can occur anywhere on the planet with little or no warning, the most extreme earthquakes occur near plate boundaries, as the plates converge (collide), diverge (move away from another), or shear (grind past one another). Moving rock and magma within volcanoes can also trigger earthquakes. In all of these cases, large sections of the crust can fracture and move to-and-fro to dissipate the released energy. This “shaking” is the sensation felt during an earthquake. The energy released is often described in terms of “magnitude,” a logarithmic scale used to describe how energetic an earthquake was; a quake of magnitude 2 is hardly noticeable without special monitoring equipment, while quakes over magnitude 8 may actually cause the ground to visibly heave and roll. Since the scale is logarithmic, a magnitude 8 quake is not four times more energetic than a magnitude 2 quake, but one billion times more energetic!

Why Do Earthquakes Happen?

Earthquakes are usually caused when rock underground suddenly breaks along a fault. This sudden release of energy causes the seismic waves that make the ground shake. When two blocks of rock or two plates are rubbing against each other, they stick a little. They don’t just slide smoothly; the rocks catch on each other. The rocks are still pushing against each other, but not moving. After a while, the rocks break because of all the pressure that’s built up. When the rocks break, the earthquake occurs. During the earthquake and afterward, the plates or blocks of rock start moving, and they continue to move until they get stuck again. The spot underground where the rock breaks is called the focus of the earthquake. The place right above the focus (on top of the ground) is called the epicenter of the earthquake.

Try this little experiment:

Earthquake-like seismic waves can also be caused by explosions underground. These explosions may be set off to break rock while making tunnels for roads, railroads, subways, or mines. These explosions, however, don’t cause very strong seismic waves. You may not even feel them. Sometimes seismic waves occur when the roof or walls of a mine collapse. These can sometimes be felt by people near the mine. The largest underground explosions, from tests of nuclear warheads (bombs), can create seismic waves very much like large earthquakes. This fact has been exploited as a means to enforce the global nuclear test ban, because no nuclear warhead can be detonated on earth without producing such seismic waves.

Where Do Earthquakes Happen?

Earthquakes occur all the time all over the world, both along plate edges and along faults.

Along Plate Edges

Most earthquakes occur along the edge of the oceanic and continental plates. The earth’s crust (the outer layer of the planet) is made up of several pieces, called plates. The plates under the oceans are called oceanic plates and the rest are continental plates. The plates are moved around by the motion of a deeper part of the earth (the mantle) that lies underneath the crust. These plates are always bumping into each other, pulling away from each other, or past each other. The plates usually move at about the same speed that your fingernails grow. Earthquakes usually occur where two plates are running into each other or sliding past each other.

Figure - An image of the world's plates and their boundaries. Notice that many plate boundaries do not coincide with coastlines.

Along Faults

Earthquakes can also occur far from the edges of plates, along faults. Faults are cracks in the earth where sections of a plate (or two plates) are moving in different directions. Faults are caused by all that bumping and sliding the plates do. They are more common near the edges of the plates.

Types of Faults

Normal faults are the cracks where one block of rock is sliding downward and away from another block of rock. These faults usually occur in areas where a plate is very slowly splitting apart or where two plates are pulling away from each other. A normal fault is defined by the hanging wall moving down relative to the footwall, which is moving up.

Reverse faults are cracks formed where one plate is pushing into another plate. They also occur where a plate is folding up because it’s being compressed by another plate pushing against it. At these faults, one block of rock is sliding underneath another block or one block is being pushed up over the other. A reverse fault is defined by the hanging wall moving up relative to the footwall, which is moving down.

Strike-slip faults are the cracks between two plates that are sliding past each other. You can find these kinds of faults in California. The San Andreas fault is a strike-slip fault. It’s the most famous California fault and has caused a lot of powerful earthquakes.

How Are Earthquakes Studied?

Seismologists study earthquakes by going out and looking at the damage caused by the earthquakes and by using seismographs. A seismograph is an instrument that records the shaking of the earth’s surface caused by seismic waves. The term seismometer is also used to refer to the same device, and the two terms are often used interchangably.

The First Seismograph

Figure - A large-scale model of Cheng Heng's original Earthquake Weathercock.

The first seismograph was invented in 132 A.D. by the Chinese astronomer and mathematician Chang Heng. He called it an “earthquake weathercock.”

Each of the eight dragons had a bronze ball in its mouth. Whenever there was even a slight earth tremor, a mechanism inside the seismograph would open the mouth of one dragon. The bronze ball would fall into the open mouth of one of the toads, making enough noise to alert someone that an earthquake had just happened. Imperial watchman could tell which direction the earthquake came from by seeing which dragon’s mouth was empty.

In 136 A.D. a Chinese scientist named Choke updated this meter and called it a “seismoscope.” Columns of a viscous liquid were used in place of metal balls. The height to which the liquid was washed up the side of the vessel indicated the intensity and a line joining the points of maximum motion also denoted the direction of the tremor.

Modern Seismographs

Figure - Two illustrations of a modern seismograph in action (from Lutgens & Tarbuck, 1989).

Most seismographs today are electronic, but a basic seismograph is made of a drum with paper on it, a bar or spring with a hinge at one or both ends, a weight, and a pen. The one end of the bar or spring is bolted to a pole or metal box that is bolted to the ground. The weight is put on the other end of the bar and the pen is stuck to the weight. The drum with paper on it presses against the pen and turns constantly. When there is an earthquake, everything in the seismograph moves except the weight with the pen on it. As the drum and paper shake next to the pen, the pen makes squiggly lines on the paper, creating a record of the earthquake. This record made by the seismograph is called a seismogram.

By studying the seismogram, the seismologist can tell how far away the earthquake was and how strong it was. This record doesn’t tell the seismologist exactly where the epicenter was, just that the earthquake happened so many miles or kilometers away from that seismograph. To find the exact epicenter, you need to know what at least two other seismographs in other parts of the country or world recorded. We’ll get to that in a minute. First, you have to learn how to

How Do I Read a Seismogram?

When you look at a seismogram, there will be wiggly lines all across it. These are all the seismic waves that the seismograph has recorded. Most of these waves were so small that nobody felt them. These tiny microseisms can be caused by heavy traffic near the seismograph, waves hitting a beach, the wind, and any number of other ordinary things that cause some shaking of the seismograph. There may also be some little dots or marks evenly spaced along the paper. These are marks for every minute that the drum of the seismograph has been turning. How far apart these minute marks are will depend on what kind of seismograph you have.

Figure - A typical seismogram.

So which wiggles are the earthquake? The P wave will be the first wiggle that is bigger than the rest of the little ones (the microseisms). Because P waves are the fastest seismic waves, they will usually be the first ones that your seismograph records. The next set of seismic waves on your seismogram will be the S waves. These are usually bigger than the P waves.

Figure - A cross-section of the earth, with earthquake wave paths defined and their shadow-zones highlighted.

If there aren’t any S waves marked on your seismogram, it probably means the earthquake happened on the other side of the planet. S waves can’t travel through the liquid layers of the earth so these waves never made it to your seismograph.

The surface waves (Love and Rayleigh waves) are the other, often larger, waves marked on the seismogram. They have a lower frequency, which means that waves (the lines; the ups-and-downs) are more spread out. Surface waves travel a little slower than S waves (which, in turn, are slower than P waves) so they tend to arrive at the seismograph just after the S waves. For shallow earthquakes (earthquakes with a focus near the surface of the earth), the surface waves may be the largest waves recorded by the seismograph. Often they are the only waves recorded a long distance from medium-sized earthquakes.

How Do I Locate That Earthquake’s Epicenter?

To figure out just where that earthquake happened, you need to look at your seismogram and you need to know what at least two other seismographs recorded for the same earthquake. You will also need a map of the world, a ruler, a pencil, and a compass for drawing circles on the map.

Here’s an example of a seismogram:

Figure - Our typical seismogram from before, this time marked for this exercise (from Bolt, 1978).

One minute intervals are marked by the small lines printed just above the squiggles made by the seismic waves (the time may be marked differently on some seismographs). The distance between the beginning of the first P wave and the first S wave tells you how many seconds the waves are apart. This number will be used to tell you how far your seismograph is from the epicenter of the earthquake.

Finding the Distance to the Epicenter and the Earthquake’s Magnitude

Figure - Use the amplitude to derive the magnitude of the earthquake, and the distance from the earthquake to the station. (from Bolt, 1978)

1. Measure the distance between the first P wave and the first S wave. In this case, the first P and S waves are 24 seconds apart.
2. Find the point for 24 seconds on the left side of the chart below and mark that point. According to the chart, this earthquake’s epicenter was 215 kilometers away.
3. Measure the amplitude of the strongest wave. The amplitude is the height (on paper) of the strongest wave. On this seismogram, the amplitude is 23 millimeters. Find 23 millimeters on the right side of the chart and mark that point.
4. Place a ruler (or straight edge) on the chart between the points you marked for the distance to the epicenter and the amplitude. The point where your ruler crosses the middle line on the chart marks the magnitude (strength) of the earthquake. This earthquake had a magnitude of 5.0.

Finding the Epicenter

You have just figured out how far your seismograph is from the epicenter and how strong the earthquake was, but you still don’t know exactly where the earthquake occurred. This is where the compass, the map, and the other seismograph records come in.

The point where the three circles intersect is the epicenter of the earthquake. This technique is called 'triangulation.'

4. Do the same thing for the distance to the epicenter that the other seismograms recorded (with the location of those seismographs at the center of their circles). All of the circles should overlap. The point where all of the circles overlap is the approximate epicenter of the earthquake.

How Are Earthquake Magnitudes Measured?

The Richter Scale

Charles Richter studying a seismogram

The magnitude of most earthquakes is measured on the Richter scale, invented by Charles F. Richter in 1934. The Richter magnitude is calculated from the amplitude of the largest seismic wave recorded for the earthquake, no matter what type of wave was the strongest.

The Richter magnitudes are based on a logarithmic scale (base 10). What this means is that for each whole number you go up on the Richter scale, the amplitude of the ground motion recorded by a seismograph goes up ten times. Using this scale, a magnitude 5 earthquake would result in ten times the level of ground shaking as a magnitude 4 earthquake (and 32 times as much energy would be released). To give you an idea how these numbers can add up, think of it in terms of the energy released by explosives: a magnitude 1 seismic wave releases as much energy as blowing up 6 ounces of TNT. A magnitude 8 earthquake releases as much energy as detonating 6 million tons of TNT. Pretty impressive, huh? Fortunately, most of the earthquakes that occur each year are magnitude 2.5 or less, too small to be felt by most people.

The Richter magnitude scale can be used to desribe earthquakes so small that they are expressed in negative numbers. The scale also has no upper limit, so it can describe earthquakes of unimaginable and (so far) unexperienced intensity, such as magnitude 10.0 and beyond.

Although Richter originally proposed this way of measuring an earthquake’s “size,” he only used a certain type of seismograph and measured shallow earthquakes in Southern California. Scientists have now made other “magnitude” scales, all calibrated to Richter’s original method, to use a variety of seismographs and measure the depths of earthquakes of all sizes.

Here’s a table describing the magnitudes of earthquakes, their effects, and the estimated number of those earthquakes that occur each year.

The Mercalli Scale

Giuseppe Mercalli

Another way to measure the strength of an earthquake is to use the Mercalli scale. Invented by Giuseppe Mercalli in 1902, this scale uses the observations of the people who experienced the earthquake to estimate its intensity.

The Mercalli scale isn’t considered as scientific as the Richter scale, though. Some witnesses of the earthquake might exaggerate just how bad things were during the earthquake and you may not find two witnesses who agree on what happened; everybody will say something different. The amount of damage caused by the earthquake may not accurately record how strong it was either.

Some things that affect the amount of damage that occurs are:

Different building designs hold up differently in an earthquake and the further you are from the earthquake, the less damage you’ll usually see. Whether a building is built on solid rock or sand makes a big difference in how much damage it takes. Solid rock usually shakes less than sand, so a building built on top of solid rock shouldn’t be as damaged as it might if it was sitting on a sandy lot.

What Are Earthquake Hazards?

Earthquakes really pose little direct danger to a person. People can’t be shaken to death by an earthquake. Some movies show scenes with the ground suddenly opening up and people falling into fiery pits, but this just doesn’t happen in real life.

The Effect of Ground Shaking

Figure - These men barely escaped when the front of the Anchorage J.C. Penny's collapsed during the 1964 Good Friday earthquake.

The first main earthquake hazard (danger) is the effect of ground shaking. Buildings can be damaged by the shaking itself or by the ground beneath them settling to a different level than it was before the earthquake (subsidence).

Figure - One side of this Anchorage street dropped drastically during the 1964 Good Friday earthquake.

Figure - These buildings in Japan toppled when the soil underwent liquefaction.

Buildings can even sink into the ground if soil liquefaction occurs. Liquefaction is the mixing of sand or soil and groundwater (water underground) during the shaking of a moderate or strong earthquake. When the water and soil are mixed, the ground becomes very soft and acts similar to quicksand. If liquefaction occurs under a building, it may start to lean, tip over, or sink several feet. The ground firms up again after the earthquake has past and the water has settled back down to its usual place deeper in the ground. Liquefaction is a hazard in areas that have groundwater near the surface and sandy soil.

Buildings can also be damaged by strong surface waves making the ground heave and lurch. Any buildings in the path of these surface waves can lean or tip over from all the movement. The ground shaking may also cause landslides, mudslides, and avalanches on steeper hills or mountains, all of which can damage buildings and hurt people.

Ground Displacement

Figure - This road, which crosses the San Andreas fault, was cut in half by the 1906 earthquake. One end of the road slid 20 feet (6.5 meters) past the other during the quake.

The second main earthquake hazard is ground displacement (ground movement) along a fault. If a structure (a building, road, etc.) is built across a fault, the ground displacement during an earthquake could seriously damage or rip apart that structure.

From Figure 4 you can tell that the San Andreas Fault is a right-lateral transverse (strike-slip) fault because the other side of the road (on the opposite side of the fault) has moved to the right, relative to the photographer’s position.

Flooding

The third main hazard is flooding. An earthquake can rupture (break) dams or levees along a river. The water from the river or the reservoir would then flood the area, damaging buildings and maybe sweeping away or drowning people.

Figure - The Seward, Alaska, railroad yard was a twisted mess after being hit by a tsunami in 1964. The tsunami was triggered by the Good Friday earthquake.

Tsunamis and seiches can also cause a great deal of damage. A tsunami is what most people call a tidal wave, but it has nothing to do with the tides on the ocean. It is a huge wave caused by an earthquake under the ocean. Tsunamis can be tens of feet high when they hit the shore and can do enormous damage to the coastline. Seiches are like small tsunamis. They occur on lakes that are shaken by the earthquake and are usually only a few feet high, but they can still flood or knock down houses, and tip over trees.

Fire

Figure - San Francisco burning after the 1906 earthquake.

The fourth main earthquake hazard is fire. These fires can be started by broken gas lines and power lines, or tipped over wood or coal stoves. They can be a serious problem, especially if the water lines that feed the fire hydrants are broken, too. For example, after the Great San Francisco Earthquake in 1906, the city burned for three days. Most of the city was destroyed and 250,000 people were left homeless.

Most of the hazards to people come from man-made structures themselves and the shaking they receive from the earthquake. The real dangers to people are being crushed in a collapsing building, drowning in a flood caused by a broken dam or levee, getting buried under a landslide, or being burned in a fire.

The history of the light bulb reads like a story straight out of a tabloid magazine. Contrary to what schools have taught for years, the American icon, Thomas Edison, neither invented the light bulb, nor held the first patent to the modern design of the light bulb.

Apparently, the we gave the esteemed Mr. Edison credit for the invention solely because he owned a power company, later known as General Electric, and a light bulb is just a bulb without a source of electricity to light it. In reality, light bulbs used as electric lights existed 50 years prior to Thomas Edison’s 1879 patent date in the U.S.

Additionally, Joseph Swan, a British inventor, obtained the first patent for the same light bulb in Britain one year prior to Edison’s patent date. Swan even publicly unveiled his carbon filament light bulb in New Castle, England a minimum of 10 years before Edison shocked the world with the announcement that he invented the first light bulb. Edison’s light bulb, in fact, was a carbon copy of Swan’s light bulb.

How do two inventors, from two different countries the invent exact same thing? Very easily, if one follows in the others footsteps. Swan’s initial findings from tinkering with carbon filament electric lighting, and his preliminary designs, appeared in an article published by Scientific American.

Without a doubt, Edison had access to, and eagerly read this article. Giving Mr. Edison the benefit of the doubt, and stopping short of calling him a plagiarist, we can say that he invented the light bulb by making vast improvements to Swan’s published, yet unperfected designs.

Swan, however, felt quite differently, as he watched Edison line his pockets with money made from his invention, and took Edison to Court for patent infringement. The British Courts stood by their patent award for the light bulb to Swan, and Edison lost the suit. The British Courts forced Edison, as part of the settlement, to name Swan a partner in his British electric company. Eventually, Edison managed to acquire all of Swans’ interest in the newly renamed Edison and Swan United Electric Company.

Edison fared no better back home in the U.S., where the U.S. Patent Office already ruled, on October 8, 1883, that Edison’s patents were invalid, because he based them upon the earlier art of a gentleman named William Sawyer. To make matters worse, Swan sold his U.S. patent rights, in June 1882, to Brush Electric Company. This chain of events stripped Edison of all patent rights to the light bulb, and left him with no hope of purchasing any.

Edison dusted himself off, and went into business setting up a direct current (DC) system of power distribution in New York City, and selling the light bulbs that used this electricity. The light bulb business only flickered between 1879 and 1889, until word-of-mouth advertising of lower electricity costs fanned the flame, and business boomed. Edison’s client base rapidly expanded to three million customers over the span of 10 years.

Always at the center of controversy, Edison next found himself in competition with Westinghouse for the sale of the first electric chair to execute criminals to New York. Edison’s chair used the DC system of electricity, while Westinghouse used the
AC (alternating current) system, designed especially for it by Nickola Tesla. Both Edison and Westinghouse emphasized the humanity of electrocution and the safety of their electrical system as selling points when pitching their chairs to New York.

Edison’s bid for the sale of his chair was a mere formality and a ploy to have the Westinghouse system of electricity chosen by New York for the electric chair. He endorsed the Westinghouse AC system of electricity as the system of choice to be used for the electric chair, reasoning that the public would associate the Westinghouse AC system with the killing power of the electric chair, and would see the system as unsafe for household use.

Edison made this strategic move in anticipation that the public and would flock to the safety of his DC system, as he needed increased sales of the system, because of the great monetary investment he had made in the system. Edison’s plan succeeded, in part, as New York did select the Westinghouse electric chair over his model.

What he could not take into account, was the fact that, unbelievably, Westinghouse never tested the chair, and the chair failed on its “Maiden Voyage.” Though Edison’s carefully laid plan went up in smoke, he did get the last laugh, as for years people referred to being electrocuted as being “Westinghoused,” even though its chair was no longer in use.

It only took a matter of years before the public realized that the benefits of the AC system far outweighed those of the DC system. Edison’s DC system took back seat, and the AC system took center stage. People in the U.S. and worldwide chose the AC system over the DC system, because AC currents deliver electricity to power lines with greater efficiency. The DC system is no longer in use today.

DID YOU KNOW?

The first light bulbs lasted a mere 150 hours, and that ten years later, Edison introduced one that lasted 1,200 hours? The average light bulb today lasts approximately 1,500 hours.

I really interested in saying that benefits by generating electricity from earth rather than generating from other resource.

Since earth is a huge matter and the collection of other resources which are stored at earth surface. When we convert wind energy into electricity we will loss the wind pressure so that the clement weather will be changing huge than what we will be benefited by the electricity. from this change of wind pressure we will get unwanted elements to earth surface from colliding of atoms.(since nature wind pressure defers when their is unstable atoms are present at the earth surface. which is due to trees). windmills better if their are more trees and good nature resources.

Electricity from water, its best when we get electricity at hills area, else it water defers(it not use able to humans or trees. since molecular forces reduces and able to get after months.)

Electricity from the earth surface will decrease the earthquakes, volcanoes,  and any sudden changes on earth. best places where electricity can be easily generated at hills, desert, where earthquakes, volcanoes, sudden weather changes, are frequently occurs.

Generating electricity from pressure. Benefitial to industries with fluids under pressure.

Norwegian company Zeropex wish to improve sustainability of communities and industries by supplying power generating pressure reduction devices. Zeropex is developing, manufacturing and selling power generating pressure reduction devices for a variety of industries, both onshore and offshore. Water utilities and oil companies see a great need for Zeropex products. Other industries with fluids under pressure may also benefit from using Zeropex products.

Pure power from pressure reduction

Difgen is a cost effective replacement for pressure chokes in all types of systems where pressure control is vital. It combines the pressure control from chokes, with electricity generation from hydroturbines, to generate pure power – at no extra operating cost. The generated power can be used to reduce your own net power bill or sold to the power grid for profit. In the water utility sector there is a great demand for Zeropex products, and spokesmen for many large water utilities claim that they have been waiting for a product like tihis for a long time. The reason is simple. The water utility sector has never before been able to control water pressure and produce electricity at the same time. This is vital for the industry. The quality and pressure of the water is key to the water sector. Zeropex give the customer full control over water quality and pressure. In addition the customer can produce power from the pressure reduction.

The UK water sector pay about 8 pence per kW, and Zeropex can offer very attractive payback and net present value for many project in the UK sector.

An offshore oil rig have between 2 MW and 12 MW available power from utilizing the energy from pressure reduction. The energy is today transferred as vibration and heat in pressure chokes. Zeropex difgen and rotachoke products will enable the operator to harvest this energy with a payback of less than two years. Harvesting this energy will also enable cleaner production offshore.

Water utilities and oil companies see a great need for Zeropex products. Other industries with fluids under pressure may also benefit from using Zeropex products.

Benefits

• Supplies electricity to your plant
• Sell electricity to the grid
• No operating cost
• Replaces pressure chokes and valves
• Utilizes excess pressure
• Reduce carbon footprint
• Increased energy efficiency
• Correlates with energy demand/price
• Utilizes existing plants
• No added environmental impact
• Supplies electricity to the plant/grid at no operating cost
• Closes the energy loop

Please note: this calculation ignores efficiency of whatever you intend to use to convert fluid-flow energy to electric energy.

the term 120cc:

If you mean a flow-rate of 120 cm^3 per sec, then you will generate 30-milliwatt!

Following on to Phil’s analysis, you should also include the cost of the water. Typical municpal water rates are 1 cent per gallon (in the US). So a 10 GPM flow is costing you $6/hour. But the electricity generated (90W) makes the rate for this electricity equal to $67 per kW-hr, as compared to a reasonable grid rate of $0.10 per kW-hr. So using household water pressure is a really expensive way to make electricity.

All you’ve said below is true, but multiple units turning water flow into electricity that run only when some one is going to use the water any way would more then offset the cost of the water itself plus feeding electricity back in to the grid. Further, the idea is to not try to get big gains, but for thousands of households to install such units obtaining a very small gain from each. Even installing such units in gutters would garner a little bit of electricity. A lot of little steps equal one huge step.

Yes, a lot of little steps forward equals one huge step forward. But if all the steps are backward, they make one huge step backward. And here is why they are all backward steps:

A few things.

First off, there it typically a pressure gradient in the water system depending on how far the residence is from the reservoir and the elevation difference between the home and the reservoir. So some houses (I believe most houses have one installed) have a pressure regulator installed on the house side of a water meter, so, in essence, a turbine could be just as easily used to lower the pressure from the street as a valve, while recovering some of the energy.

That being said, I doubt there would be a generator/ turbine anywhere near efficient enough to make this plausible or useable.

At least it’s forward thinking, even if it results in backwards results.

Alternatively, a home could set up their own water reservoir in their attic, to gain an energy boost from gravity. I envision a large tank (appropriately supported) which has a level switch so that it turns on water from the street as water is used to maintain a constant volume of water in the house. Depending on the amount of water in the tank, a large potential energy store could be created, potentially with a larger pressure gradient than the street pressure. Slap a turbine on the outlet valve for the reservoir and generate electricity there.

Again, I don’t feel like doing the fluids and thermodynamics to find out how much height/ volume would give a usable pressure, and I’m sure that there would be a significant danger in thousands of pounds of water in the attic. So it’s probably not at all plausible, but it’s an interesting problem to think about.
Relying once again on Phil Corso’s analysis posted earlier, a typical 10 gpm flow would generate 90 watts while it is flowing. It is generating zero watts when water is not flowing. And since you are hypothesizing this generator as something that only runs when you would be using water anyway, we must consider how much of a typical day is spent drawing water at the rate of 10 gpm.

Let’s leave farming and golf course watering out of the discussion and focus only on residential homes. They consume water when you draw a bath, do the laundry, or wash dishes. I think it would be generous to say that 10 gpm flows for about 1 hour per day. 90 watts one hour per day is 32.85 kw-hr over a one year period. At $0.10 per kw-hr, that produces $3.29 worth of electricity per year. Whatever water turbine/generator you install to capture this power is certainly going to cost you more than $200. With this kind of investment, and getting $3.29 back per year, you will recoup your $200 investment in 61 years. I doubt that any $200 turbine/generator is going to last 61 years without maintenance. So you will never break even, so it was a step backward.

Another thing that extracting energy from the domestic water suppy does is lower the pressure at the point of use. In fact, to gather 90 watts, you will have to lower the pressure to almost nothing. That is going to be pretty inconvenient for taking a shower, or just about anything else. If there was excess pressure in the water supply, then the proper thing to do would not be to deploy millions of little generators to capture that energy. The proper thing to do would be to lower the municipal water pressure and realize the savings by not having to pump as hard – all without any capital investment at all.

A few things.

First off, there it typically a pressure gradient in the water system depending on how far the residence is from the reservoir and the elevation difference between the home and the reservoir. So some houses (I believe most houses have one installed) have a pressure regulator installed on the house side of a water meter, so, in essence, a turbine could be just as easily used to lower the pressure from the street as a valve, while recovering some of the energy.

That being said, I doubt there would be a generator/ turbine anywhere near efficient enough to make this plausible or useable.

At least it’s forward thinking, even if it results in backwards results.

Alternatively, a home could set up their own water reservoir in their attic, to gain an energy boost from gravity. I envision a large tank (appropriately supported) which has a level switch so that it turns on water from the street as water is used to maintain a constant volume of water in the house. Depending on the amount of water in the tank, a large potential energy store could be created, potentially with a larger pressure gradient than the street pressure. Slap a turbine on the outlet valve for the reservoir and generate electricity there.

Again, I don’t feel like doing the fluids and thermodynamics to find out how much height/ volume would give a usable pressure, and I’m sure that there would be a significant danger in thousands of pounds of water in the attic. So it’s probably not at all plausible, but it’s an interesting problem to think about.

We know that you can’t get something for nothing and that tapping the house water pressure will take away from the pressure at the tap. But if you utilize a water line where the pressure drop is not an inconvienence, like the washing machine, you could realize modest returns.

Modest is the key word. Using the house pressure to run a pump that pumps a low volume of rain water from a cistern up to an attic resevoir would be useful. Use it to flush the toilets. Toilets are big water wasters and do not require potable water. So using the otherwise unused potential of your house’s water pressure to save water makes sense. (Not to mention it is enviromentally friendly).

Based on annual rainfall, the area of your collection surface (your roof) and your water bills, you could calculate how long it will take you to break even. In my neck of the woods (South suburbs of Chicago) it will take under three years.

you are right, its costly to generate from water from municipality. But how about using free water flow, the one from sewer or drainage flowing in city. its free and waste, do you think we can use the flow for generating electricity. the flow is not strong enough but I think its present throughout year and endless, I think we can use this resource just like solar or wind, that’s useful from waste.

I would like to offer a better solution or better question to the answer. If you would like to augment the power generation which charges a battery system that is fed by other means of charging then this is a great idea. Other systems meaning solar, or wind. There are off peak times when solar and wind cannot produce the power needed to charge a batter. A simple shower or watering of the grass may provide that extra boost. Have a nice day.

What about people that happen to run swimming pools with pump systems that run from 4 to 8 hours per day. Could some advantage be taken of this? It is a closed system that needs to run anyway.

What if we were to tap the main the comes from the water tanks that feed the water systems? Yes a pump is used to fill the tank but the water that comes from these tanks, and feeds the whole community is gravity based why waste this energy resource?

About people that happen to run swimming pools with pump systems, there is no advantage that could be taken, unless the pump system was seriously over-powered. If a swimming pool pump system is properly designed, then the pump is just powerful enough to circulate water through the pool. If the pump is more powerful, and water is being circulated faster than needed, then the thing to do is not to try to recapture that excess energy with a turbine. The thing to do would be to replace the pump by a smaller pump and not waste that energy in the first place.

As for tapping the gravity-based outflow of a municipal tank, that too is not the best use of resources. Those tanks are built as high as they are to get the needed pressure to run the system. If there is excess energy in the system, then the tanks should have been built lower in the first place. The only truly excess energy that has been cited in this thread is the energy that gets wasted in the pressure-reducing regulators. And even in that case the economics of the situation is such that the gain from a turbine would never outweigh the capital expense of installing the system.

I’ve been interested in all the information on this topic. I have a small stream running right through my property and I’d like to be able to harness the potential of being able to generate enough electricity for our residential needs. Can anyone suggest anything to help me please??

Check out http://www.ecoinnovation.co.nz/c-55-hydro-generators.aspx
Mike can customise a system for any head, any available flow.

Yes, see if you can conveniently enlarge the stream :^). Seriously though, people need to consider just how much power it takes to run our modern conveniences. It’s a lot for anything that heats or is motorized. From a small stream, if you have enough head on your property, you might be able to provide basic LED lighting for example. For an example, look to the once common water driven grain mills. It was a lot of doing to get a few HP, but it’s free once it’s paid for. Thoughts of “going off the grid” have often occurred to me lately, I have the Rum River flowing through my property and I’ve pondered a water wheel driving a car alternator to charge batteries. The local power cooperative has been most encouraging in these schemes, not that they would want me to do it, but by the incentive their 10.4 cents per kwh rate provides. The Rum will freeze solid soon, which curbs those thoughts.

If you can find it, 20-something years ago Smithsonian Magazine did a feature on the use of low-head pelton wheel turbines to power residences with streams available. There is/was a Chinese company that was making an Allis-Chalmers knock-off pelton wheel that was being used with good results.

Unfortunately, Smithsonian’s online archives only go back to 2003, and this was sometime in the early 1980s or late 1970s.

Suffice it to say that you can make a small bypass dam in your stream and put a Pelton Wheel style turbine generator in it that requires relatively low head to operate.

You need to calculate the energy available based on physics before you go any further. What is the water flow? What size of head (drop) do you have available? Would you need to build a dam (and would you be able to get planning permission for it)? What is the *minimum* seasonal water flow?

1 W = 1 N*m/s = 9.8 * 1 cubic-metre * 1000 / sec

So, 1 cubic metre per second of water falling a distance of 1 metre would give you 9.8 * 1000 kg * 1 m = 9.8 kw. That’s a useful amount of power, even once you subtract efficiency losses.

However, 1 cubic metre per second is also a fair amount of flow for a “small” stream. If you only have 1 litre per second of flow, then you only have 9.8 w (not kw!). That’s not enough to light a light bulb, even a small CF bulb. If you have more head (drop), then you can generate more power will less flow. However, unless you have very favourable geography, you probably don’t have a lot of head to work with on a small property.

Small 19th century water powered grist, flour, or saw mills typically operated on no more than a couple of kilowatts. That’s why most of them were abandoned when electricity became available instead of being converted into power generation plants. Unless your location happens to be very good, generating your own hydro tends to be more of an interesting hobby than anything else.

http://www.control.com/thread/1026244600

Please advice me on same.

Thanks and regards

A few weeks back I did some investigations into the current state of etheses submissions.  From reading webpages and speaking to a fair few other repository managers (thanks guys) I built up the following rough and ready picture of what is happening in the UK at the moment.  It’s in no way comprehensive, and I apologise if I misinterpreted anyone’s online policy – let me know and I’ll modify the details below.

To confuse matters with terminology slightly (which seems to be an IR standard!) Where I mention moratorium that’s what we use in Leicester for temporary delay.  Embargos here are more serious, semi-permanent->permanent withholding.  Some places use these terms interchangeably, but I’ve tried to standardise for how we understand them here.

• Aberystwyth UniversityOpt out mandate 2008-. PhD and selected MA/M.Scs.  Automatic moratorium 2 years.  Author requested moratorium/embargo period up to 5 years (or indefinitely), co-signed by supervisor
• Birkbeck, University of London (1994 Grp) No thesis mandate currently but planned
• Brunel UniversityOpt out mandate 2008-. No student requested moratorium.  Formal embargo applied for by supervisor (3 year fixed term) to Research Support Office
• Cambridge University (RLUK) Opt in mandate
• Cardiff University (RLUK) No thesis mandate currently, but one planned
• Cranfield University Opt out mandate
• De Montfort University Opt out mandate
• Durham University (RLUK) (1994 Grp)
  Opt out mandate 2009.  No author request moratorium period.  Author may apply for (up to) 5 year embargo through formal process.
• Edinburgh University (RLUK)Opt out mandate 2005-.  1 year moratorium, repeatable.  5 year embargos can be applied for.
• Glasgow University (RLUK) Opt out mandate 2007/8 -.  Author requested moratorium standard period of 3 years (with extension if required, eg commercial confidentiality). Permanent embargos agreed between the student, primary supervisor and the graduate school so the institution wouldn’t apply an embargo in isolation.
• Goldsmiths, University of London (1994 Grp) Opt in mandate
• Imperial College London (RLUK) Opt out mandate.  No author requested moratorium.  Formal embargo maximum two years may be applied under special circumstances.
• Institute of Education, University of London (1994 Grp) Unclear, possibly opt in mandate
• King’s College London (RLUK)
  No thesis mandate
• Leeds Metropolitan University No thesis mandate currently but planned
• LSE (RLUK) Opt in mandate
• Loughborough University (1994 Grp) Opt out thesis mandate 2009-. No author requested moratorium.  Supervisor/HoD can request up to 3 year moratorium for “restricted access” theses
• Newcastle University (RLUK)
  Opt in thesis mandate currently deposit “strongly encouraged”
• Queen Mary, University of London (1994 Grp) Unclear, possibly no mandate.
• Queen Margaret University, Edinburgh Opt out mandate.  Ethesis only submitted.
• Robert Gordon UniversityOpt out mandate.
• Roehampton UniversityOpt out mandate. Author requested moratorium, no time period specified
• Royal Holloway, University of London (1994 Grp) Opt out mandate from 1/Oct/2010-.  2 year author requested moratorium.  Formal application for longer institutionally applied embargos.
• School of Oriental and African Studies (1994 Grp) (RLUK) Unclear, possibly no mandate
• Trinity College (Dublin) (RLUK)Opt out mandateUniversity College London (RLUK)

  Opt out mandate

• University of Aberdeen (RLUK) Unclear, opt in mandate suspected
• University of Abertay, DundeeOpt out mandate
• University of the Arts, London
  Opt in mandate
• University of Bath (1994 Grp) Opt out mandate.  Author requested 1 year maximum moratorium.  Formal embargo (max 3 years) on application to Board of Studies.  Formal embargo (longer than 3 years) discussed by senate.
• University of Bolton No thesis mandate currently
• University of Birmingham (RLUK)
  Opt out mandate.  4 year author moratorium.  Formal embargo possible on application to senior committees
• University of Bradford Opt out mandate 2009-.  No mention of embargo/moratorium in policy
• University of Bristol (RLUK) Opt in mandate
• University of Central Lancashire
  Opt out mandate 1/Sept/2010.  Authors may request moratoriums to be approved by Graduate Office. Embargoes will be applied for purposes of IPR, confidentiality etc
• University of Chester Opt in thesis mandate
• University of East Anglia (1994 Grp) Opt in mandate, Apr 2010. Authors may request a moratorium. No formal embargoes.
• University of Essex (1994 Grp) Unclear, possibly no mandate
• University of Exeter (1994 Grp) Opt out mandate 2008-.  Author requested moratorium up to 18 months.  Up to 5 year embargo can be formally requested
• University of GreenwichCurrently considering opt out mandate (Sept 2010). Mandates and embargos not yet decided
• University of Hull Opt out mandate Sept 2008-. Author requested moratorium up to 5 years. Rare, v. special exceptions for long term embargo
• University of Hertfordshire
  Opt out mandate 2007 –.  Author requested moratorium up to 2 years.  Author can apply for permanent embargo formally.
• University of Huddersfield Opt out mandate 2007-.  Author requested 2 year moratorium.  Formal embargo for up to 10 years on application
• University of Lancaster (1994 Grp) No mandate yet, but in planning stages
• University of Leeds (RLUK) Opt out thesis mandate.  Author requested moratorium up to 5 years.  20 year embargo for thesis where a patent is pending
• University of Leicester (1994 Grp) Opt out mandate, 2008-. Up to three year student requested post-award delay. Semi/Permanent embargo on formal application to Graduate Office/Senate
• University of LincolnNo thesis mandate currently
• University of Liverpool (RLUK)
  Opt out mandate 2008-.  No author requested moratorium.  Formal up to 5 year embargo on application to HoD & Supervisor
• University of Manchester (RLUK) Opt out mandate 2009-.  No author requested moratorium. Formal embargoes on application to Graduate Office, strongly discouraged.
• University of Nottingham (RLUK) Opt out mandate 2009-.  2 year author requested moratorium.  Permanent embargo on application to appropriate university committee
• University of Oxford (RLUK) Opt out mandate 2007 (PhD, M.Litt and M.Sc (Res).  3 out of 4 divisions have author requested moratorium (3 years max).  Formal longer term embargo can applied (term TBC by Graduate Studies) to Supervisor and Director of Graduate Studies
• University of Reading (1994 Grp) Unclear, possibly no mandate.
• University of Salford No mandate currently, but planning work underway.
• University of Sheffield (RLUK)Opt out thesis mandate 2009-.  Author requested moratorium up to 5 years. 20 year embargo for thesis where a patent is pending
• University of Southampton (RLUK) Opt out mandate
• University of St Andrews (1994 Grp) Opt out mandate, 2006-.  No author moratorium. Senate approved embargo can be applied for. Up to 5 years on print and/or electronic, for commercial, sensitive, pre publication/copyright reasons. Permanent embargo possible but exceptional. Abstracts and even title can be embargoed on request
• University of Stirling
  Opt out mandate
• University of Strathclyde Opt out mandate
• University of Surrey (1994 Grp) No thesis mandate
• University of Sussex (1994 Grp) Opt out mandate 2009-.  Electronic only thesis submission
• University of Wales, Institute Cardiff (UWIC)
  Opt out mandate
• University of Wales, Newport No mandate currently.
• University of Warwick (RLUK)Opt in mandate
• University of Westminster Opt out mandate
• University of WolverhamptonOpt out mandate
• University of York (1994 Grp) Opt out mandate 2009-.  Author requested moratorium 2 years maximum.  Embargo must be formally requested and approved

Key

Opt out mandate = student deposit of ethesis is required, unless under regulations a delay is permissible.

Opt in mandate = encouragement but not requirement to deposit.

I should note a few places asked me to redact their not-public-yet policies – so some of the omissions are due to that, and I’m more than happy to respect people’s professional wishes.  I think what I’ve taken away from this brief survey is that what we do here at Leicester is pretty much slap-bang in the centre of what other comparator institutions are doing.  Mandates for etheses deposits are very widespread throughout the UKHEI sector as a whole, and clearly where they aren’t already in place, I’d expect over the next year or so to see most if not all institutions adopting them.  Certainly one thing that is evident from the LRA statistics month after month is that these etheses are much more heavily consulted than the print ones ever were.

One of the first, and most vital, steps every new business takes is the selection of a name.

Choosing the name of your busness wisely will have much to do with its subsequent success. That’s because people will make critical decisions simply based on your business name.

It is true that people make snap decisions about other people based on simple 7-second first impressions. After those first few moments, it gets pretty hard to change someone’s mind about that person later.

In the same way, people make snap decisions about your business based on first impressions. The first thing many people see is your name. With a good name, you will warrant further scrutiny. But if you chose a name poorly, the consequences can be disastrous.

An early note of caution is needed here. In cases where the business is already established, be careful about changing the name. You may lose the equity which has already been built and established. However, if you need to come up with a new company name, here are some guidelines to help you.

Reflect your target niche.

First, your business name should clearly reach your target audience. Is your offer or claim understandable? Two good name selections are the 7-11 and Hot ‘N Now stores. Your name should also fit your logo and slogan. In addition, clarity about your desired geographical service area helps people understand your business. All-City Shoe Repair tells me that they will fix shoes anywhere in my community. That’s pretty clear!

However, don’t use any geographical descriptions if that could ever become a limiting factor. For example, would a company called Eastside Bookkeeping ever do work for someone located downtown? In addition, geographical names tend to get overused. To see what I mean, go to the white pages of your phone book and see how many business names start with the name of your city or state.

Clarify what your business does.

Your business name should let the customer know what you do. Although Aaacme Services, Inc. may be listed first in your section of the Yellow Pages, a business card given to a new acquaintance doesn’t tell the receiver what your business does. If a person can’t remember why they have your card, they will quickly discard it. Two good names are Jiffy Lube and Fast Signs. And if you can attract your customers properly in the first place, they’ll probably never even notice that they passed three of your competitors on their way to see you.

Keep the name simple.

Keep your business name short and easy to say, spell and remember. Avoid tongue twisters like Watson, Smith, Howiczak, Elton and Elton. Imagine the poor secretary who has to write down a message from that company!

Also avoid acronyms or names using initials unless they will mean something to your typical customer. If IBM had been started using that name instead of International Business Machines, it is doubtful that they would have been as successful. Letters mean little or nothing to your customer, and as a result, are quickly forgotten. IBM didn’t begin using that name until the marketplace had already bestowed the shortened name upon them.

Keep the name flexible.

Don’t let your name restrict you to a field that you may grow out of. Make the name expandable. As an example, Canned Software Company may sound good at first, but what happens if you decide to get into the computer hardware business? Or what if Mr. Smith ever leaves or sells Smith Watch Company. If it fails, what does that do to his reputation?

Avoid trendy names.

It seems that every few years, some new naming trend makes the rounds. How many times have you seen some type of name using Something-a-Rama or Something ‘R Us? After these fads run their course, you will be left with a stale and outdated name, and that’s probably what most people will think of your company too!

Avoid amateurish or silly names.

Names like Bambi’s Secretarial Service typically will not generate the confidence of your potential customers. If I were looking for a professional service, I’d be much more inclined to call ASAP Secretarial Services. For the same reasons, avoid silly names. They will wear thin very quickly. Curl Up and Dye may sound cute now, but after six months, you and your customers will become very weary of the joke.

Is it unique and can it be protected?

You want your name to stand out in front of your customers and prospects. Avoid names that are close, or even similar to your key competitors. If all your competitors use variations of XYZ Janitorial Supply, position yourself differently with a distinctive name like EnviroSafe Products. Finally, take steps to be sure that your name is protected and preserved in your marketplace. Similarly, be sure that you are not encroaching on anyone else’s trademark or identity.

One of the basic truths in SEO is that even if you do all the things that are necessary to do, this does not automatically guarantee you top ratings but if you neglect basic rules, this certainly will not go unnoticed. Also, if you set realistic goals – i.e to get into the top 30 results in Google for a particular keyword, rather than be the number one for 10 keywords in 5 search engines, you will feel happier and more satisfied with your results.

Although SEO helps to increase the traffic to one’s site, SEO is not advertising. Of course, you can be included in paid search results for given keywords but basically the idea behind the SEO techniques is to get top placement because your site is relevant to a particular search term, not because you pay.

SEO can be a 30-minute job or a permanent activity. Sometimes it is enough to do some generic SEO in order to get high in search engines – for instance, if you are a leader for rare keywords, then you do not have a lot to do in order to get decent placement. But in most cases, if you really want to be at the top, you need to pay special attention to SEO and devote significant amounts of time and effort to it. Even if you plan to do some basic SEO, it is essential that you understand how search engines work and which items are most important in SEO.

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From every body we can get a little bit of electricity since (energy neither created nor destroyed according to The first law of thermodynamics)

Ground source heat pumps connect nature’s friendly ground temperatures to your facility or home. Let us help you understand how the earth is ready, willing and able to provide free energy, create your own utility service, and how to size your systems to get the most efficient energy transfer possible for your facility. Our experienced staff and test providers can help you put the earth to work efficiently.

Efficiency should not be confused with conservation. As opposed to conservation (sacrifice), energy efficiency is an indispensable component of any effort to improve productivity. Ultimately, energy efficiency contributes to wealth.

SPECIFICATIONS FOR DIRECT MEASUREMENT
OF EARTH THERMAL CONDUCTIVITY TESTING

• Thermal conductivity test should be performed for 36 to 48 hours. The time may be
shortened at the determination of the data interpreter using experience in the area.
• The heat rate (heat of rejection) is to be 15 to 25 watts per ft. (50 to 80 W/m) of
borehole. These heat rates are the expected peak loads on the test borehole for an
actual heat pump system. Heat rates should increase as the borehole diameter
increases, as the borehole depth increases, and as the grout resistance increases. As
the ratio of effective diameter of the heat rejection tubes to the borehole diameter
increases the heat rate decreases.
• The standard deviation of input power is to be less than + 1.5 % of the average value
and peaks less than + 10% or resulting temperature variation less than + 0.5°F (0.3°C).
• The accuracy of the temperature measurement and recording devices are to be +0.5°F
(0.3°C). · The accuracy of the power transducer and recording device is to be +2% of
the reading.
• Flow rates are to be in the range to provide a differential loop temperature of 6 to 12°F
(3.5 to 7°C). This is the temperature differential for an actual heat pump system.
• A waiting period of five days is recommended for low-conductivity soils [k < 1.0 Btu/hr-ft-
°F (1.7 W/m-°C)] after the ground loop has been installed, grouted, and filled with water
before the thermal conductivity test is initiated. A delay of three days is recommended
for higher conductivity formations [k > 1.0 Btu/hr-ft-°F (1.7 W/m-°C)].
• The initial ground temperature measurement is to be made at the end of the waiting
period by direct insertion of a probe inside a liquid filled ground heat exchanger at three
locations representing the average or by the measurement of temperature as the liquid
exits the loop during the period immediately following start-up. Ewbank uses the exiting
fluid temperature while pumping measurement and records at one second intervals.
• Data collection should be at least once every 10 minutes. Ewbank collects data points at
one minute intervals and test duration is only limited by file size.
• All above ground piping is to be insulated with a minimum of 0.5 inch (1.25 cm) closed
cell insulation or equivalent. Test rigs are to be enclosed in a sealed cabinet that is
insulated with a minimum of 1.0-inch (2.5 cm) fiberglass insulation or equivalent.
• If retesting a bore is necessary, the loop temperature should be allowed to return to
within 0.5°F (0.3°C) of the pretest initial ground temperature. This typically corresponds
to a 10 to 12-day delay in mid to high conductivity formations and a 14-day delay in low
conductivity formations if a complete 48-hour test has been conducted. Waiting periods
will be proportionally reduced test terminations occurred after shorter periods.
• Any of the public domain software programs tested in conjunction with ASHRAE 1118-
TRP, with the exception of the Line Source method that only ignores the first 0.08 hours
of data, can be used to evaluate thermal conductivity. It is suggested that multiple
programs be used to further enhance reported accuracy.
• A well completion report (driller’s or lithologic log) is required to estimate the thermal
diffusivity. No direct measurement methodology has been established for thermal diffusivity.
• Static water level in the formation should be noted and dry formations noted.
Groundwater produced while drilling should be noted.
• Lost circulation zones and occurrence of natural gas should be noted.

______________________________________________________________________________
Thermal Conductivity Testing Specification and Procedures

The following specifications and procedures for thermal conductivity testing are designed to achieve the best possible test results with the current test equipment and methods. May update and alter these specifications and procedures as new equipment or methods are developed.

Equipment
The portable test unit is connected to an installed loop with one side connected to the  supply outlet and the other side connected to the return inlet. The test unit measures and records flow (gallons per minute), supply and return temperature (degrees F), voltage, amperage and time.

Data is recorded every minute. All data is measured to three decimal places. The test unit
should be kept dry and protected from dust. In extreme temperature conditions the test unit should be wrapped in additional insulation. For accurate results, it is imperative that the test unit and above ground piping do not gain or lose heat.

A portable computer is connected to the test unit with a serial cable. The data is recorded into a specified file on the hard drive every one minute. The computer may be plugged into the test unit receptacle for power supply.

Purging
The loop and test unit must be purged of air and pressured to at least 10 psi. If the air is not removed, or the loop pressurized, the circulating pump may stop pumping or pump at varying rates. For accurate results, it is imperative that the test unit and loop is purged of air and pressurized to achieve a constant flow rate during the test.

Test unit hook up
The loop ends should be attached to the unit with hose clamps and inspected to make sure the connections do not leak. The portion of the loop and hoses that are above ground and outside the test unit should be well insulated to ensure that heat is not gained or lost between the ground and test unit.

Power Supply
The test unit requires a stable power supply. If line power is utilized, (not recommended), the extension cord should be of adequate gauge to minimize voltage drop. A twelve gauge electric cord is recommended. If a generator is used, it should be have a capacity of at least twice the wattage that will be required for the heating elements. Approximately 15 to 25 watts per foot should be used to heat the loop (a 200 feet borehole would require 3,500 watts). The wattage should be observed periodically to ensure the power input is stable. After initial stabilization of power, if the wattage decreases or varies more than 1.5% from the average power, the test may not provide accurate results. Make certain that the circuit breakers are of sufficient amperage to carry the load.

The line source/slope method of interpreting data is the only method that has been proven reliable through research and verification. When using this method it is imperative to have constant power (+/- 1.5% of the average power). Put simply, this method measures the temperature rise over time with a constant heat input. Variations in the rate of heat input change the rate of temperature rise. When line power is the only source of power, longer test times are required to “average out” the power variations.
It is Ewbank and Associates experience that power supplied by a generator provides much more reliable results. With the line source/slope method of interpretation, the slope of the temperature curve on a log time scale is the variable in the equation. When the slope is consistent over a 4 to 6 hour period, the results are more reliable than when the slope is constantly changing and an average or “best fit” is used.

Data
Temperature and wattage readings should be monitored periodically to check for erratic or unusual data. The data is recorded to a file every minute. When the test is completed, the data is transferred to Ewbank for interpretation and reporting.

Test length
The undisturbed formation temperature should be measured by observing the temperature of the water as it returns from the loop to the test equipment at startup. The test should be at least 36 to 48 hours in length for best results. The recommended test duration is dependent on the borehole diameter, thermal conductivity of the grout or backfill, position of the loop in the borehole, and thermal conductivity of the formation. Generally, the less efficient the borehole is for transferring heat, the longer the test duration (large borehole diameter compared to the equivalent diameter of the loop).

Since the borehole is usually less conductive than the formation, the material in the borehole must be heated to a higher temperature so that it will transfer heat at the same rate that the formation is conducting the heat. When the borehole is conducting heat at the same rate as the formation, the test unit is measuring the temperature rise in the formation. More efficient boreholes require less time to reach this point. Typically, the end of the “borehole effect” can be observed on the graph of the temperature on a log  time scale. A “dog leg” or flattening of the curve is usually evident.

It is the experience of Ewbank and Associates that longer duration tests, such as 48 hour tests, must be carefully analyzed so that results are not overstated. As the temperature rises near the borehole, heat moves away at an increased rate due to the higher  temperature differential to drive the heat. Consequently, the temperature rise per unit of time during the last portion of test is much less than that of the first portion of the test. When the temperature raises only a small increment over a period of time, any  environmental effects or power fluctuations can dramatically alter the calculated results.

Equipment damage
Shipping and handling of the test unit may cause damage. Equipment should be handled with care during transport. Equipment is designed for durability, but the unit may require repair from time to time.

Thermal Conductivity Testing Instructions

1. Place test unit near borehole and loop. If the area is wet or muddy, set unit on blocks or other means to keep unit dry and clean.
2. Check loop pipes to see if they are full of water. If they are not full, use water supply to fill them.
3. Connect the loop ends to the test unit using short lengths of hose, hose adapter fittings and hose clamps.
4. Make sure the purge valve is closed. Connect the water supply to the water fill inlet  and open the valve. Open flow control valve to full flow. Open the water supply valve and fill the loop and test unit.
5. Connect power supply cords, the thermistor cords, and the flow meter cord between the pump box and the electronic box. Connect power supply from the power source to the
electronic box. Power outlet should have adequate size ground-fault circuit breaker.
6. Connect computer to the test unit by connecting the serial computer cord from the electronic box to the computer serial port. Start the computer test program. At C> type name of execute program. Answer questions as prompted. You will be asked the path and filename to be used to store the data. Type C:(and the filename for the test) and press enter. After entering test information and choosing to continue, the test data screen will appear on the computer. On the left side of the screen will be the temperatures, voltage, amperage, flow, watts, and times saved read-outs. Check for proper temperatures and voltage.
7. With water supply on, the water supply valve open, and the flow control valve open to full flow, turn the circulating pump switch located on the electronic box to the “ON” position.
8. The system must be purged of any air. Open the purge valve enough to allow air to vent. Observe water in purge hose for air. When no air is observed with the purge valve\ open, the system is air free. Purging process should be conducted at least 15 minutes to ensure air is removed from system. Make sure purge valve is closed when finished.
9. After air is purged, close water supply valve. System should have at least 10 psi.
10. Turn on the primary heating element by putting the primary heat switch located on the electronic box to the “ON” position. Observe wattage and temperature readings. When using auxiliary (second) heating element, plug in second electric cord to auxiliary power supply with the auxiliary heat off, then turn the auxiliary power switch to the “ON” position.
11. Slowly close the flow control valve until the supply temperature is approximately 3 to 4 degrees higher than the return temperature.
12. Wattage and temperatures should be monitored periodically during test. Erratic readings indicate inadequate power supply or air in the system.
13. Recheck all loop connections and valves for any leaks. Make sure all piping, hoses, and the test unit are well insulated.
14. Test should be run for at least 36 to 48 hours. Computer should be kept clean and dry.
15. After completion of test, turn off computer and disconnect from test unit. Turn off and disconnect power supply. Disconnect loop and other hoses. Drain water from test unit.

A stable power supply must be available for accurate results
All air must be purge from the system for proper testing
Carefully insulate the piping from the unit to the ground. Armaflex ¾” thick is
recommended, with foil lined bubble wrap insulation wrapped around armaflex.

PHYSICAL PROPERTIES OF MATERIALS
Thermal Conductivity of Various Substances
The following is a listing of the ratios of how fast heat is conducted through each material. The information is useful as a comparison of one substance to another. Large numbers indicate greater conductivity characteristics.*
Air . . . . . . . . . . . . . . . . . .0.0568
Aluminum . . . . . . . . . .480.0
Antimony . . . . . . . . . . . .44.2
Argon . . . . . . . . . . . . . . .0.0389
Asbestos, paper . . . . . . .0.6
Bismuth . . . . . . . . . . . . .17.7
Blotting paper . . . . . . . . .0.15
Brass . . . . . . . . . . . . . .204.0
Brick, aluminum . . . . . . . .2.0
Brick, building . . . . . . . . .1.5
Brick, carborundum . . . .23.0
Brick, fire . . . . . . . . . . . . .3.1
Brick, graphite . . . . . . . .25.0
Brick, magnesia . . . . . . . .7.1
Brick, silica . . . . . . . . . . .2.0
Cadmium . . . . . . . . . . .222.0
Carbon gas . . . . . . . . .130.0
Carbon graphite . . . . . .290.0
Carbon dioxide . . . . . . . .0.0307
Carbon monoxide . . . . . .0.0499
Carborundum . . . . . . . . .0.50
Cardboard . . . . . . . . . . . .0.50
Cement, portland . . . . . . .0.17
Chalk . . . . . . . . . . . . . . .0.28
Charcoal, powdered . . . .0.22
Clinkers, small . . . . . . . . .1.1
Ice . . . . . . . . . . . . . . . . . .3.9
Iron, pure . . . . . . . . . . .161.0
Iron, cast . . . . . . . . . . .109.0
Iron, wrought . . . . . . . .144.0
Lamp black . . . . . . . . . . .0.07
Lead . . . . . . . . . . . . . . .83.0
Leather, cowhide . . . . . . .0.42
Leather, chamois . . . . . . .0.15
Lime . . . . . . . . . . . . . . . .0.29
Linen . . . . . . . . . . . . . . . .0.21
Magnesia . . . . . . . . . . . .0.3
Magnesium, carb . . . . . . .0.23
Marble . . . . . . . . . . . . . . .8.4
Mercury . . . . . . . . . . . . .19.7
Mica . . . . . . . . . . . . . . . .0.86
Nickel . . . . . . . . . . . . .142.0
Nitrogen . . . . . . . . . . . . .0.0524
Oxygen . . . . . . . . . . . . . .0.0563
Paper . . . . . . . . . . . . . . .0.31
Paraffin . . . . . . . . . . . . . .0.62
Pasteboard . . . . . . . . . . .0.45
Plaster of Paris . . . . . . . .0.42
Plaster, mortar . . . . . . . . .1.3
Platinum . . . . . . . . . . .170.0
Plumbago . . . . . . . . . . . .1.0
Poplox (Na2Si03) . . . . . .0.13
Porcelain . . . . . . . . . . . . .4.3
Coal . . . . . . . . . . . . . . . .0.30
Coke, powdered . . . . . . .0.44
Concrete, cinder . . . . . . .0.81
Concrete, stone . . . . . . . .2.2
Copper . . . . . . . . . . . .918.0
Cotton wool . . . . . . . . . . .0.043
Cotton batting, loose . . . .0.11
Cotton batting, packed . . .0.072
Earth, average . . . . . . . . .4.0
Eiderdown, loose . . . . . . .0.108
Eiderdown, packed . . . . .0.045
Feathers . . . . . . . . . . . . .0.16
Felt . . . . . . . . . . . . . . . . .0.22
Fiber, red . . . . . . . . . . . . .1.1
Flannel . . . . . . . . . . . . . .0.035
German silver . . . . . . . .80.0
Glass, crown . . . . . . . . . .2.5
Glass, flint . . . . . . . . . . . .2.0
Gold, . . . . . . . . . . . . . .700.0
Granite . . . . . . . . . . . . . .4.5
Gutta percha . . . . . . . . . .0.48
Gypsum . . . . . . . . . . . . .3.1
Hair . . . . . . . . . . . . . . . . .0.15
Hair cloth, felt . . . . . . . . .0.042
Helium . . . . . . . . . . . . . . .0.339
Horn . . . . . . . . . . . . . . . .0.087
Hydrogen . . . . . . . . . . . .0.327
Petroleum . . . . . . . . . . . .0.39
Pumice stone . . . . . . . . .0.43
Quartz, pr. to axis . . . . .30.0
Quartz, perp. to axis . .160.0
Rubber, hard . . . . . . . . . .0.43
Rubber, Para . . . . . . . . . .0.38
Sand, dry . . . . . . . . . . . .0.86
Sandstone . . . . . . . . . . . .5.5
Sawdust . . . . . . . . . . . . .0.14
Silica, fused . . . . . . . . . .2.55
Silk . . . . . . . . . . . . . . . . .0.13
Silver . . . . . . . . . . . . . .974.0
Slate . . . . . . . . . . . . . . . .4.8
Snow . . . . . . . . . . . . . . .0.60
Steel . . . . . . . . . . . . . .115.0
Terra Cotta . . . . . . . . . . .2.3
Tin . . . . . . . . . . . . . . . .155.0
Water . . . . . . . . . . . . . . .1.6
Wood, fir, with grain . . . . .0.30
Wood, fir, cross grain . . . .0.09
Wool, sheep . . . . . . . . . .0.14
Wool, mineral . . . . . . . . .0.11
Wool, steel . . . . . . . . . . .0.20
Woolen, loose, wadding . .0.12
Zinc . . . . . . . . . . . . . . .265.0
* Expressed in gram–calories/second/square centimeter/centimeter/°C

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