Author: Isaac Gendler

Concentrated solar power

Concentrated solar power

Concentrated solar power

02/06/17

“Is there a way to generate solar power without using photovoltaics?”

 

Solar PV systems are one of the most ingenious gifts that technologists have bestowed upon humanity. However, engineers are a rather creative people and like to do the same thing in multiple ways. So how can we “re-invent the wheel” when it comes to solar power? Well, we know that the sun produces sun rays. And if we focus these sun rays onto a focal point, then a large amount of energy can be transferred to an object that point. So what if we were to take a large array of concave lenses, focus all of the sunlight onto a source of water, and use the resulting energy to turn said water into steam to drive a turbine that generates electricity? This is the operating principle behind a system known as concentrated solar power and is commonly used in highly irradiated areas such as California, Spain, and South Africa.

The physics of a football tackle

The physics of a football tackle

The physics of a football tackle

02/05/17

“How do the laws of physics affect football tackles?”

 

Because of the excitement for the super bowl stateside, a fan recently asked for an article about the science of football.

 

If you are from the United States, then you have probably seen or heard about a game called “football” where people divided onto two teams will fight each other for control of a prolate spheroid shaped ball using tackles. However, have you ever wondered about how one can make an optimal tackle? Well, it turns out that all you need is a rudimentary knowledge of physics to find out.

        Every object in the universe has a property called a center of mass, or the location of the mean position of matter in a body. When a force is applied on an object which does not go through the center of mass, a torque will be induced, causing a rotation on said body. So now let’s put this theoretical framework into practice. The average human male has their center of mass located slightly above the navel. When one football player tackles another in this area, the player will simply be moved in the direction of the tackle. But if the player were to give a tackle below this zone, a torque would be induced that would completely throw off the player! Luckily, professional coaches have taken note of this, and use this scientific knowledge to advise linemen to stay close to ground while running, making it far more prohibitive for a disabling torque to be thrust upon them!

Science always shows up in the most marvelous ways in our everyday life, and it goes to show that a small bit of knowledge of it can go a long way.

Dual rotor wind turbines

Dual rotor wind turbines

Dual rotor wind turbines

02/04/17

“Could we make wind turbines more efficient by adding a second rotor?”
       The wind turbine is one of the finest inventions that humanity has conjured. It is simply amazing how these machines can take in the kinetic energy of the wind and transfer it into power to be used by humans. However, the designs of these machines often come with a problem. The rotor of the turbine, one of the most important components of the device, disrupts the surrounding wind, inducing turbulence and lowering the amount of energy to be obtained. So how could we use our engineering mindsets to solves this problem? Well, Aerospace Engineers Anupam Sharma and Hui Hu of Iowa State University made a thorough investigation on this problem, and discovered that one way to solve this problem is actually to add a second rotor to the turbine! This would not only increase the amount of energy absorbed, but also prevent much of the unwanted turbulence. This team is currently working on optimizing the design, such as the location of the turbine, the direction it should take, the size, and what kind of airfoil the dual rotor wind turbine should have.

Transistors

Transistors

Transistors

02/03/17

“How can we apply our knowledge of semiconductors to create electronic switches?”

 

P and N type semiconductors are highly useful devices for creating a controlled electric current. However, how could we apply this technology to create something incredibly useful? Well, let’s use our technical mindset to figure this out. We know that if an N type and a P type were hooked up together and the P type had a higher voltage than the N type,, then a flow of extra electrons from the N type (called the “emitter” would come in to fill the P type (called the “base”). Furthermore, if there was an another N-type (called the “receiver”) electron on the other side of the P-type that was even more positively charged, then we would be able to not only have an electron flow but be able to control the amount of current flowing. However, our only problem is that this operation can only take place if both the base and the receiver had a positive voltage. This can be easily fixed through applying a positive voltage to the base, allowing not only for a current to take place but control of the current and voltage to happen as well, effectively making a switch with no moving parts! This is the foundation of an electronic component known as the transistor, and is what allowed for the modern computer revolution to have taken place!

P and N-type semiconductors

P and N-type semiconductors

N-type semiconductors

02/02/17

“What are the fundamentals of the fundamentals of solar cells?”
Solar cells are one of the most magnificent devices that humanity has conjured. However, what exactly makes them tick? To find out, let’s go take a look. If one were to analyze a solar cell with a magnifying glass so powerful that it could see in the microscopic level then we would find a multitude of small, three terminal devices. These devices are known as Transistors and have very special properties. Specifically, it can work as a switch without moving parts! However, before we understand transistors, we must understand what cause them to work. Half of the composition of transistors are composed of objects known as P-type and N-type semiconductors. P-type semiconductors hold an impurity of boron[B], which holds one less electron than silicon, while N-type semiconductors are  have a small impurity of phosphorous [P], which holds an extra electron than silicon. When combined, these semiconductors will have more mobile charges and can conduct current better.

Solar night lighting

Solar night lighting

Solar night lighting

02/01/17

“How can we light up the night using solar power?”

 
Turning on lights at night is one of the key requirements for safety in a populated area. However, such lights can be very taxing on the electrical grid. Could there be a way to circumvent this issue? Well, let’s think about it. We know that solar panels can be used to generate energy independent of the grid. And we also know that all of the excess energy can be stored in the batteries at night. So what if we were to take solar panels, generate some energy during the day, and then store it in batteries, so when the night comes, our lights can have a power source independent of the grid? This most fascinating setup is known as solar lighting, and is very useful for the fact that not only does it beneficial for the environment but also beneficial for a user’s wallet through net metering!

Renewable energy penetration

Renewable energy penetration

Renewable energy penetration

01/31/17

“What do scientists mean when they talk of renewable energy penetration?”

 

Often times, scientists will mention a term called “renewable energy penetration” when discussing sustainable systems. Now, the name itself probably comes off as a tad bit confusing, so what exactly do they mean? Well, renewable energy penetration simply means the amount of power in the electric grid that is supplied by renewable sources. This term is not just a simple measure of energy generation but is a phenomenon that energy engineers, planners, and policymakers must focus their active attention on since a grid with a high renewable percentage will have to deal with novel effects such as the duck curve and microgrid integration.

The duck curve

The duck curve

The duck curve

01/20/17

“What happens when demand and generation from renewable energy is out of sync?”

 

There is one nagging bump on the road to achieving a truly sustainable society. The energy generated from renewable sources is not constant but varies throughout the day. Specifically, the peak power generation happens during noon, when the sun is shining the brightest, and the minimum occurs after sunset. However, Human energy consumption has a tendency to be the opposite, since individuals are away from their homes during noon and return in the evening. This means that grids with a high sustainable penetration rate often struggle to cope with this imbalance of supply and demand, which manifests itself as a duck curve. One way to fix this issue would be to invest into a large amount of energy storage such as batteries or vehicle to grid technology.

Vehicle to grid technology

Vehicle to grid technology

Vehicle to grid technology

01/29/17

“Could we use the batteries of electric vehicles to power our homes?”

 

Renewable energy has a problem. The peak times for generating such power (mid-day) is often not in sync with the peak stress on the grid (sunset, when solar energy is no longer available), and local battery storage can be quite expensive. So how can we circumvent this issue? Well, let’s use our engineering mindsets to solves this problem. One of the main problems stems from the lack of affordable energy storage. However, many sustainability conscious individuals also own electric vehicles. And in these electric vehicles are electric batteries which often times have excess energy. So what if when these cars were parked at night, they would feed energy back into the local smart grid to power homes? Well, this is the main idea behind a system which researchers refer to as vehicle to grid technology, which is not only environmentally friendly but economically with the use of net-metering.