DESIGN TEMPTATION

Hybrid Solar-Thermal Facade (Linear concentration)

2012-02-23T17:47:00.009+01:00

Summary

Lightfarm is a new method for utilizing building facade and rooftop in order to collect and concentrate light rays which then is used for heating and power generation by CPV photovoltaic cells. this kind of PV are two times more efficient than normal silicon PV cells and are suitable for concentrated light.

in this project, instead of using conventional photovoltaic of 12% to 19% efficiency, the sunlight would be concentrated by building façade using the thin plastic fresnel lenses, and then an small surface of LCPV would generate electricity for the household with high conversion rate of 28 % .

while photovoltaic cells would provide electricity with an efficiency of 28%, 72% waste of energy is transmitted to heat-sinks for water and space heating purposes.
Expansion of 20 sq meters of this system on the rooftop or 25 meters on facade is expected to supply a household with half of the entire annual energy usage.

LIGHT FARM

(Facade Light Harvesting)

Lightfarm is a system that utilizes building facade and rooftop for collecting and concentrating light rays which then is used for heating and power generation by LCPV photovoltaic cells. This kind of PV has an efficiency of 28% and is suitable for concentrated light up to 10 to 40 times the intensity of sun rays.

In this case, instead of using conventional photovoltaic of 12 to 19% efficiency, we would concentrate light by building façade using the thin plastic Fresnel lenses , and then utilize a few Sq. decimeters of LCPV to generate electricity for the household.

Photovoltaic cells would provide electricity with an efficiency of 28%, and the 72% formerly waste of energy is transmitted to heat-sinks for water and space heating purposes.

MAIN FEATURES OF THE SYSTEM

-Heat generation even in cold but sunny winter days: The main advantage of this system is the capacity to harvest sun Heat even in winter days as the concentration let us to collect the whole energy of the sun light in a small area and overcome the problem of current thermal systems which is equity of sunlight absorption and ambient loss due to very low temperature of the ambient in winter.-Power generation with high efficiency (30% Cell / 25% Module efficiency)

-Integration with building’s façade and rooftops: Integration of system with buildings could be considered an advantage in 2 aspects. First of all it could be a substitution for façade decoration which means a very considerable cut in building construction expenses, the second advantage is aesthetical aspects which is some cases the normal PV panels don’t really match with the buildings architectural design.

-Active tracking system: (Deployment of active solar sensor and driver which makes the design very easy to install without complicated prior regulations.

Very low energy consumption of actuators due to high static load capacity and short travelling strike and low duty cycle.

-Aesthetical aspects: Glass facades are still very trendy and fashionable, Many new modern buildings are still being designed with glass façade and this trend is increasing every day, but LightFarm is not just a Normal Glass façade, there are features which makes it Far more attractive than a conventional Glass façade…

Optical Art can change the face of the new buildings forever; Remembering the fact that Fresnel Lenses are some sort of magnifier , this can demonstrate the new approach for beautification and personalization of building’s façade base on the choice of the of the buildings’ owner. It’s enough to put a small design motif around the focal point of the lens, this small piece of art would be magnified by the lens and turn into the view of the building when someone is looking.

main advantages of the system are:

Higher efficiency (Min 50% combined heat and electricity)
Providing hot water even in cold sunny days
Aesthetical aspects and possibility of doing graphic design on the buildings solar façade.

Optical art:

Optical art makes an attractive solution out of linear CPV facade.

Sustainable solutions doesn’t necessarily require to compromise the aesthetics of the buildings,

Not anymore.

Invisible Photovoltaic panel:

In contrary of current black PV panels which in many cases doesn’t match with the design and gestalt of the buildings, Linear lightfarm delivers a versatile, integrated and user defined selection of DESIGN.

Vertical facade light harvesting (winter solution)

Facade light harvesting has a considerable advantage in winter times compared to conventional solar thermal solutions on rooftops. The fact is that in cold winter days with a sun which travels in an inclined plane in the sky, the amount of energy absorbed by the thermal collector surfaces is hardly more than the loss of the heat due to very low temperature of surrounding ambient. with concentration of sunlight we change this balance and make it possible for the thermal collectors to receive more energy than what they lose by radiation and air convection.

CPV modules as colorful high efficiency glass facade

This project is successor of High concentrated solar facade project : In linear project however I have tried to simplify as much as possible and to adapt the concept for easier integration. here is a video of the previous project:

RWS recumbent bicycle

2012-01-23T13:59:00.021+01:00

Preface

After one year of having a concept of rear wheel steering bike, finally got the hands dirty to complete the design of Alpha version and make its prototype…

Recumbent bikes have their own pros and cons comparing to upright bikes. They are more ergonomic and very comfortable compared to upright bikes and also have a great advantage in aerodynamics.

There are also drawbacks associated with these type of bikes Here I don’t want to make a list of all disadvantages.

But the main objectives that pushed me into starting this project were:

- To get rid of long chains of current recumbent bikes:

- To get rid of Interference of legs with steering front wheel, which results in conventional supine position of the body for common recumbent bikes.

- Designing a recumbent bike with more potential to be used in urban environments .( a bike that is easier to stop and start the movement considering constant traffic interruption in cities)

The design concept:

This new concept is rear wheel steering front wheel drive recumbent with power transfer system directly on front wheel. Power Direct power transfer has been achieved by using a specially designed epicyclic gearing set with possible progressive shifting system. Steering mechanism is placed on rear wheel and is composed of a 4 bar linked kinematic system in order to achieve a lean steer RWS which surprisingly is configured with negative trail(read more on steering description). The design is a try to adapt recumbent bikes for urban use and change the nature of this bike from sports cycling to urban transportation cycling …

But before everything there are issues that should be indicated:

Potential advantages of a rear wheel steering , front wheel drive recumbent bikes( of which we can mention simpler transmission mechanism and separation of steering wheel and brake wheel) has inspired many designers to go for a RWS system design, In Late 70’s US National highway safety administration(NHSA) commissioned a project to develop a Safe motor bike with key idea of lower center of mass, longer wheel base and separation of steering and braking…The last requirement leads naturally to a design with rear-wheel steering, since the front wheel provides the major contribution to the braking force. The result was reported to NHSA with a recommendation that it was pointless to build a prototype because the motorcycle could apparently not be ridden.

In spite of the all the negative signs of considering RWS Bikes inherently unstable, I started my own adventure with the hope to achieve some advances… the least achievement would be better understanding of bikes by studying dynamical behavior of RWS.

But what makes front-steering bicycles, FSBs stable and rear-steering bicycles, RSBs, unridable?

Here is a simplest response to this question that I quote from HPV magazine, By Craig J Cornelius:

“In simplest form, a bicycle can be thought of as two-mass system. The larger mass is made up of the main frame, the rider and the driven wheel, and the smaller mass is made up of the steering frame(fork), steered wheel, handle bars , etc. the rider maintains stability by directly controlling system velocity , steering angle and lean angle indirectly.During a steady-state Maneuver either riding in straight line or executing a constant acceleration turn, the two major system perturbations are to steering angle, which primarily relates to steering frame or to the lean angle which primarily relates to main frame.A correctly designed FSB has a mechanism to correct each of these disturbances. Disturbances to the steering angle are corrected for by the phenomenon of caster. Caster or positive trail is defined as the distance the steered wheel’s ground contact patch is behind the intersection of steering axis and the ground, behind being is defined as the opposite the direction of desired motion. Positive trail results in a torque being developed whenever the plane of the steered wheel is not aligned with the direction of the motion. For small steering angles this torque is roughly proportional to the steering angle and acts to reduce the steering angle. As a result any disturbance to the steering angle is corrected by the negative feedback associated with positive trail.Disturbance to the lean angle are corrected by the phenomenon of lean steer. The kinematics of a typical bicycle are such that the tendency of the system to reduce its potential energy results in a torque that steers the bicycle in the direction that it is leaned. As a result as a result, a disturbance which causes the main frame to lean sideways, initiates a turn in the direction of the fall. The radial acceleration due to that turn results in a force that acts to lift the bicycle out of the fall. As with positive trail lean steer results in negative feedback to the disturbance that initiates it.The mechanism of positive trail and lean steer allow a bicycle to be ridden with the rider’s hand of the handlebars. In addition these mechanisms are usually strong enough to allow a bicycle to remain upright in the absence of the rider above some minimum speed.The auto stability of a FWS bike is direct result of positive trail and lean steer. Fortunately both mechanisms occur together in an FSB.In RSB positive trail results in reversed Lean steer and conversely lean steer is present only with negative trail. I have investigated numerous combinations of fork offset and fork rake for single pivot steering systems as well as a number of four bar linkage positioning Mechanisms, and have not found a steering method that combines both positive trail and lean steer. This inability to obtain both disturbances correcting Mechanism in the same configuration is why RSBs are inherently unstable.
In designing a simple RSB, then, one must choose among positive trail, Lean steer, or a neutral configuration that exhibits neither phenomenon.”

For further studies The following articles are more detailed: Bicycle dynamics and control, By Karl J. Åström and also Bicycle dynamics By Arend Schwab.

RWS recumbent; Steering solution with negative trail…

The critical point of an RWS concept however is to find a solution to make a stable design: My solution for this problem is a kinematic mechanism for steering which provides both Lean steer and positive trail effects in the same time.

To solve the problem of instability of RWS I had to devise a mechanism that provides sort of a instantaneous steering axis.

As you can see in demonstration of steering mechanism, steering axis is far behind the wheel’s contact patch with the ground… with conventional definition of the trail or caster, this configuration results in negative trail and consequently the inability of controlling the bike in higher speeds, But the thing that makes this design different is the fact that steering axis

in this mechanism is not stationary and it actually moves instantly by steering the wheel;

This mechanism is configured in a way that although it seems to have a negative trail configuration, but disturbances caused by steering develops a torque that tends to correct steering (in contrary of what we expect from negative trail which tends to steer violently upon steering)

This configuration also provides lean steer effect due to tendency of the system to reduce potential energy while leaning.

Direct Power transmition: (Planetary Hub Gear)

Having a fixes front wheel has 2 main advantages:

- separation of steering and braking

- Possibility to use hub gears directly on the front wheel.

As I was planning to build the prototype of this RWS bike and there is nothing as hub gear in market for direct power transfer system without using chain, I have designed my own planetary gear for this bike.

I had a concept about a hub gear which would installed directly on the front wheel without any need to chain, here I simplified it for prototyping and the result is a 2 speed planetary gear set that could be easily prototyped.

Planetary gear ratio depends on which part is fixed and which part is moving:

Planetary gears are usually made of A ring gear, a sun gear, and a set of 3 or 4 planetary gears that are linked together.

I have used ring/Sun/Planetary Gears with relatively 42/18/12 teeth.

Working out the gear ratio of a planetary gear train can be tricky. Let's denote the following:

T_r	Turns of the ring gear
T_s	Turns of the sun gear
T_y	Turns of the planetary gear carrier (the Y shaped thing in the previous photo)
R	Ring gear teeth
S	Sun gear teeth
P	Planet gear teeth

The turning ratio is as follows:

( R + S ) ×T_y = (R × T_r )+( T_s × S)

By default I would fix outer ring by a disk brake, In this case the gear ratio is 3.33( 1 +42/18) but there is this opportunity to release the disk brake and let the outer ring to rotate, in this case output ratio differs from fixed configuration and it’s suitable for starting the bicycle movement.video1 video2

By using a disk brake which in our case is used as a clutch, we can let the disk and consequently the ring gear to rotate… depending on the brake pressure ,gear ratio would change from 3.33 to 1.00 and this gear shifter works in a linear way.

I already know that there is some waste of energy due to friction, I still have not calculated the amount of this wasted energy, so till performing a proper calculation and test, let’s say that we use this gear set just as a 2 speed gearbox. High gear of 3.33 and low gear ratio of 1.00

Click to view assembly process

2 different ratio modes would be achieved like this: (Note that in this design the pedal is used as the planetary carrier. So the driving components are 3 planetary gears and the sun is driven component)

1- High Gear:

If we hold the ring gear in a fixed position, T_r will always be zero. So we can remove those terms from the above formula, and we get: T_s/T_y = (R+S)/S=(18+ 42/18) =3.3

With the fixed disk & Ring gear, and the planet gears connected to the pedals as driving elements, turning the pedals and consequently the set of 3 planetary gear carrier, would cause the sun gear and consequently the hub and wheel, to turn 3.3 times.

2- low gear:

According to the formula, and considering that planetary gear carrier as the driving element, if We let the disk and ring gear to rotate, the sun gear would turn with a less angular velocity, at its extreme if we let the ring to turn freely, it would be ring that rotates with a low gear ratio but higher torque, and the sun gear would not turn at all. As you see it literally mean that by controlling of ring’s rotation we can adjust the ratio of rotation of sun gear and hub and wheel in a linear manner.

Again to avoid any kind of waste we let the ring to rotate freely without any friction but we would limit the rotation by a freewheel bearing that doesn’t allow the ring to overrun the hub and the sun gear… this would result an equilibrium of

T_r	=T_s	=T_y

And the gear ratio equals to T_y / T_s =1 which is a convenient ratio to gain speed while starting the bicycle movement.

I am also very keen to know if linear gear change would work efficiently or not, so in very near future I am going to conduct the efficiency test of this gear set.

More Photos of the bike...

Known Issues with current design:

· Long wheelbase which results in larger turning radius.

· Weight distribution: almost 60% rear to 40% front wheel; I would probably have to change this configuration for next design

· Using cable to steer the rear wheel seems that is not so practical, I used cable as it enables us to integrate bicycle seat and steering handle bars. Connecting the handle bars stem to seat is an advantage as by adjusting the position of seat, the handle bars would also be in the right place without any further adjustments.

· The steering center of gravity is located in a position which doesn’t contribute to lean steering and actually it produces a reverse torque that resists against lean steer.

· Etc…

Known Issues with current prototype:

Despite my efforts to build a high quality prototype, The prototype is quite wobbly…
The current steering mechanism is also too rigid and that’s because the 4 bar axis are not completely parallel. As a result with some extra weight it requires a lot of force to steer
The frame and steering mechanism made of iron and is too heavy. The mass of steering mechanism in particular is causing problems for auto-stability of the bike.
I made a mistake to use and weld head-tubes which are slightly bigger than upper and lower head-tube races.(almost 0.5 mm bigger) As a result, head tube races are not fit in tubes(0.5 tolerance) and and it might be another reason that contributes in blockage of my steering mechanism under my weight.( I have to change the head tubes with standard ones)

RWS Trike

2012-01-23T13:14:00.002+01:00

I have been living in Milan for last 3 years and I didn’t see either a single trike or a recumbent bike, for sure out of the city and also other countries we might see more recumbents, inspite all great advantages f recumbent bikes which the most important of them could be comfort and less aerodynamic drag, but thinking and searching about the reasons that recumbent are not as popular as normal upright bikes, lead to some obvious facts:

Recumbent bikes are usually more expensive than normal upright bikes… or at least you cannot find a cheap one as easy as finding a cheap upright bike.
Riding a recumbent requires some practice and not many people are keen on new experiences…
Recumbent bikes seem too sporty for an urban environment. And they are not easy to stop and start in constant traffic interruptions.

Considering these facts; Main objective of the new design is to:

simplicity
Affordability: to make it possible to classify it as a low-cost bicycle. My goal for the price is a Trike around 200 euro
Make it easy to ride with a normal appearance and ordinary rider pose without any need to wear sporty costumes…

I have simplified the concept over and over again and the right now MSA-Trike is as simple as possible while I think I have not compromised so much of its functionality…

The lean steer effect has been applied to design by tilting the head tube a bit forward and it is proportional to the steering angle. Amount of this lean-steer effect has been adjusted for the average speed of 15 Km/h

Regarding the power transmition, I had a concept about a hub gear which would installed directly on the front wheel without any need to chain, here I simplified it for prototyping and the result is a 2 speed planetary gear set that could be easily prototyped.

Planetary gear ratio depends on which part is fixed and which part is moving:

Planetary gears are usually made of A ring gear, a sun gear, and a set of 3 or 4 planetary gears that are linked together.

I have used ring/Sun/Planetary Gears with relatively 42/18/12 teeth.

Working out the gear ratio of a planetary gear train can be tricky. Let's denote the following:

T_r	Turns of the ring gear
T_s	Turns of the sun gear
T_y	Turns of the planetary gear carrier
R	Ring gear teeth
S	Sun gear teeth
P	Planet gear teeth

The turning ratio is as follows:

( R + S ) ×T_y = (R × T_r )+( T_s × S)

By default I would fix outer ring by a disk brake, In this case the gear ratio is 3.33( 1 +42/18) but there is this opportunity to release the brake and let the outer ring to rotate, in this case output ratio differs from fixed configuration and it’s suitable for starting the bicycle movement.

2 different ratio modes would be achieved like this: (Note that in this design the pedal is used as the planetary carrier. So the driving components are 3 planetary gears and the sun is driven component)

High Gear:

If we hold the ring gear in a fixed position, T_r will always be zero. So we can remove those terms from the above formula, and we get: T_s/T_y = (R+S)/S=(18+ 42/18) =3.3

low gear:

T_r	=T_s	=T_y

And the gear ratio equals to T_y / T_s =1 which is a convenient ratio to gain speed while starting the bicycle movement.

I am also very keen to know if linear gear change would work efficiently or not, so in very near future I am going to make a prototype of this gear set.

------------------------------------

PS: I am also planning another experiment with this concept Trike:

As you see the seat is slightly inclined toward forward; I cannot assert that this is a optimum configuration in terms of comfort, but the reason I did it like this, is my understanding that in current recumbent seats, the rider doesn’t have so much maneuverability, as the body weight is being supported by the back and therefore the rider can not move the body and lean as free as an upright bike. With this concept and shifting some of the rider’s weight on the feet, it might be easier to move the body and have a better control over the vehicle. We can walk for hours and hours with the whole weight of the body on the feet, I guess it also wouldn’t be so tiring for the feet to bear few percentage of the body’s weight during a short urban ride for the sake of the safety and also avoiding so called “leg suck” problem.

LIGHT FARM

2011-10-11T11:12:00.016+02:00

Light-farm prototype(Hcpv Version)
& me with a Fresnel Magnifie

(Facade Light Harvesting)

Lightfarm is a system that utilizes building facade and rooftop for collecting and concentrating light rays which then is used for heating and power generation by HCPV photovoltaic cells. This kind of PV has an efficiency of 40% and is suitable for concentrated light up to 500 to 1000 times the intensity of sun rays.

In this case, instead of using conventional photovoltaic of 12 to 19% efficiency, we would concentrate light by building façade using the thin plastic Fresnel lenses accompanied by a glass layer, and then utilize a few Sq. centimeters of HCPV to generate electricity for the household.

Photovoltaic cells would provide electricity with an efficiency of 40%, and the 60% formerly waste of energy is transmitted to heat-sinks for water and space heating purposes.

Household energy consumption in a year in temperate places equals to 20000 KWH averaging a medium power consumption of 2280 watts. Every Sq. meter of sunlight contains 1000 to 1350 watts. It means that just 2 meters of constant sunlight energy would provide a household with sufficient energy. But unfortunately neither are sun rays available constantly nor are our harvesting devices that efficient yet. Considering 5 hours of average daily sunshine with medium intensity of 900 watts, with photovoltaic cells of 17% efficiency, an area of 75 meters of photovoltaic cells would provide a house with its energy requirement.

MAIN FEATURES OF THE SYSTEM

HCPV modules on Building facade

-Power generation with high efficiency (40% Cell / 25% Module efficiency)

-Active tracking system: (Deployment of active solar sensor and driver which makes the design very easy to install without complicated prior regulations.

Very low energy consumption of actuators due to high static load capacity and short travelling strike and low duty cycle, deployment of conventional and economical sensors and actuators in market with some minor changes)

-Economical viability.

According to the most reliable research institutes, CPV would replace the conventional PV panels in near future, due to high efficiency and lower price per/watt energy generation, which could compete to fossil energy.

In specific the lightFarm project promises a really competitive alternative to fossil energy as the system is been designed for integrity with buildings which is the end user for electricity and heat consumption.

The LIGHTFARM design consists of 4 main parts which all of them have been deployed in an economical way:

- Structure: the structure would be made of steel or aluminum profiles.

-Lenses/Primary optics: are Made of PMMA polymer sheets and they get shaped by an economic process.

PMMA material costs less than

2 euro/Kg which is very economic and the process of manufacturing could also be very economic in case of a high volume of production.

Insulation of module

Triple junction high efficiency solar cell

SOE/ HCPV cell / heat-sink

- HCPV cells: Each HCPV cell Assembly consists of a square shape HCPV Cell of 10x10mm and it substitutes an area of 300x300 mm photovoltaic cell. It means that the area has been reduced to 1/900 of the original area while the price of the cell has just increased about few times more than conventional PV.

Each HCPV cell assembly consists of HCPV cell+ substrate and heat transfer diode+ secondary optic, would cost around 25 Euro (less than 250 Euro/Sq meter) in mass production.

Considering the prices of main components of the system and also the fact that expenses of this system are not additional expenses, in fact it would totally replace to a normal facade system and it doesn’t require much extra funds compared to a normal glass facade.

All in One solution:

Light-farm is the optimum solution for areas which don’t have so many cloudy days in year compared to sunny days; as the system efficiency drops dramatically in case of cloudy and rainy weather.

For places with more than yearly average sun of 250 watts sun, an expansion of 25 sq meters of Fresnel lenses would definitely supply the household with the required energy of the house. But the system also generates and harvests HEAT…

25 meters of sunshine contains 25000 Watts of energy, 15000 Watts ( 25000- 25000x40%) would convert to HEAT of which roughly 10000W is the amount that could be harvested through heat sinks.

10 KW of HEAT is a considerable figure and the first question which would rise afterwards is : What to do With the HEAT harvested?

Building Designed specifically for integration with lightfarm project (Designer: Nasser Taghavi)

Saving the HEAT

Special Heat-sink designed specifically
for water circulation in light-Farm

As far as I am aware of, Light Farm is the first project that proposes integration of HCPV solar in building’s facade and this brings a huge advantage to the project compared to its precedents, previously to get rid of heat was considered as an expense for solar power plants out of the city while in this project the heat would be directly used in building for water and space heating. Yet there should be a proper system to save the HEAT for the use through the day and night.

The Fact is that the efficiency of converting HEAT to any other form of energy is so low, thermocouples can convert maximum 10 percent of energy to electricity and other methods are not also so efficient.

LIGHT-FARM instead proposes an easy and practical solution to save the HEAT. The solution is “Paraffin wax”

Paraffin wax is mostly found as a white, odorless, tasteless, waxy solid, with a typical melting point between about 46 and 68 °C (115 and 154 °F) and this specific melting point is exactly what makes an attractive solution of paraffin wax to save the HEAT. The question remains: How?

The algorithm of saving heat is like this:

-Sun rays hit the HCPV cells and convert to 40% electricity+ 60% Heat.

- The HEAT produced (10 KW for 25 Sq. meters) would be transmitted to the water(or any other thermal fluid) inside heat-sink through the aluminum fins.

Water Tank enclosed by Paraffin wax

- a thermostat would turns on the pump as the temperature of heat-sink exceeds 45° and cold thermal fluid would be circulated in heat-sinks and tank.

- There would be a water tank of 400 Liters for each family to save the hot water, The pump circulates the water(or thermal fluid) inside the heat-sinks and the tank( in case of using thermal fluids, the heat would be transmitted to the water inside the tank through a radiator “heat exchanger”)

-The Heat capacity of water is Cp= 4.18 J/(g•K) so the temperature increases by around 20° each hour

- The maximum efficiency of the HCPV cells would be achieved at 25° centigrade, increasing the temperature would decrease the efficiency (1% for every 20° increment) and to avoid damages to the cell, it is better to keep the cell temperature less than 80° so there must be a way to control increasing of temperature.

- The tank would be enclosed by a volume of 400 kg of Paraffin wax with melting point of 65°. So the water temperature would increase in a linear manner until it reaches the melting point of the paraffin wax around the water tank. At this point there wouldn’t be any change in the temperature until the whole mass of paraffin is melted. And this requires a lot of energy,

enthalpy of fusion, also known as the heat of fusion or specific melting heat of Paraffin equals to 220 J/g and it means that the fusion of one gram of Paraffin requires 220 joules of energy.

400 kg of wax would require 220 x 400 x 1000 Joules of energy to melt and it requires 2 hour and half for the harvested Heat to melt this amount of Paraffin.

Good thing about this solution is the sheer amount of the saved heat for using during night and also maintaining the temperature on the melting point of the paraffin which is 65°.

Low price of paraffin (2 euro/kg) guaranties an economical solution out of this method.

Winter facade light harvest:

(Linear version)

CPV modules as colorful glass facade

To reduce complexity of project and to make it more viable there is the possibility to use linear Fresnel lenses, in this case the tracking would be applicable just in one direction, apparently the choice of tracking direction would be south-north tracking since there is just little changes in angle of sun rays in south-north direction(almost 1° every 8 days), this means that the tracking could also be done manually on a weekly basis,

Inspirations for Optical solar facade

Advantages:

-Less technical complexity,

-Aesthetics.

-Compatible with vertical facade

-Winter solution( this configuration is more adaptable for winter days since the sun is not anymore at its zenith and sun beams have an inclined angle. therefore linear method is more adaptable for vertical glass facade

Disadvantages:
linear Fresnel lenses doesn’t have high rate of concentration and for this reason it is not economical to use HCPV cells, instead we have to use CPV cells designed for low concentration of 10 to 40 suns intensity, apparently the efficiency of CPV cells are less than HCPV(around 28%)

Optical art:

First experiment with linear module...

Optical art makes an attractive solution out of linear CPV facade.

Sustainable solutions doesn’t necessarily require to compromise the aesthetics of the buildings,

Not anymore.

Invisible Photovoltaic panel:

Animated gif( Click to enlarge)

LINEAR FRESNEL FACADE (winter solution)

Vertical facade light harvesting has a considerable advantage in winter times compared to conventional solar thermal solutions. The fact is that in cold winter days with a sun which travels in an inclined plane in the sky, the amount of energy absorbed by the thermal collector surfaces is hardly more than the loss of the heat due to very low temperature of surrounding ambient. with concentration of sunlight we change this balance and make it possible for the thermal collectors to receive more energy than what they lose by radiation and air convection.

About the prototype:

The realized prototype is an array of 4 modules; Each module harvests an area of 30x30 cm and the sunlight then would be concentrated into a 10x10 mm HCPV cell. In order to reduce the demand for accuracy, a prism-shaped secondary optic would lead the concentrated light into the cells.

The cells are placed on a heat sink which absorbs the heat from the cell and produces hot water.

All the modules are capable to turn in al directions and all of them are connected together in a way that by moving one of them all the system moves together.

In this way by using an active sensor and a pair of linear actuator motors the modules track the sun’s position in the sky. There is a small gap between modules to let the modules turn freely without interference and also to avoid overlap of the shadow of one module on active area of another modules. so in contrary of normal PV modules which in different time of the day the solid angle( The solid angle, Ω, is the two-dimensional angle in three-dimensional space that an object subtends at a point. It is a measure of how large that object appears to an observer looking from that point) of the PV against the sun reduces as the sun gets away from its zenith; but in the Light-Farm prototype although there is a gap between the modules but the area of sun ray harvested in whole the day remains the same, Thanks to tracking system which makes the modules always face the sun, so the solid angle is always the same(for example a module of 30x30 cm always receives 30x30cm of sun ray)

2-Axis solar tracker

Linear Actuator

300Kg Dynamic Load

2-axis solar tracker would determines the sun position and the electronic driver would command 2 linear actuators in south-north & east-west directions.

The thermostat device reads the temperature of the Cell assembly Thanks to a thermocouple attached to the heat-sink. It gives the possibility to adjust the temperature in which pump starts and stops to circulate the thermal fluid.

INPUT/OUTPUT

- Linear actuators consume the power in a periodic timing due to low duty cycle( during the whole day, they would be working just for few minutes and in most of the time they just bear static load without consuming any power)

At the moment both Actuators and sensor driver are connected to an adaptor of maximum 22 Watts output and it works properly.

According to the figures and considering flaws in prototype accuracy, the overall efficiency of system in harvesting sunlight is around 50% in forms of electricity and Heat, Which promises a high efficiency result by a proper industrial manufacturing system.

History of the project: (Former Concept)

The concept of Lightfarm project occurred to me last year when I was trying to design a method in order to transfer sunlight into the internal rooms of large buildings for lighting purpose during the day.

The very first concept was to concentrate light by special parabolic or Fresnel modules into a collector,

The harnessed light then could be transferred into the buildings, using fiber optics,

Concept was cool but it was not justifiable as it was not at all economically viable to install those equipments just for few hours of natural light during the day. Contemplating on the problem and noticing the sheer amount of the sunlight energy hitting the façade and rooftop every day, finally I got to the point that the system should be shifted from light transferring into light harnessing: a system that concentrates sunlight and converts it to electricity and collectable heat. The completion of design coincided with announcement of Foundation Enterprise Hermes for the competition.

To present the project properly, I asked an old friend of mine (Nasser Taghavi) to help me with the design of a building suitable for integrating with lightfarm system, the result of this collaboration is the detached house with light collectors on rooftop. The design showcase compatibility of HCPV solar on rooftops, yet there is more to be done in Design of the different variations, specially design of a building for Linear Facade Light harvesting.

Possibility of collaboration:
This project is not yet fully formed and still needs a lot more research & development, that's why I humbly invite all individuals, research institutions and companies interested in this solar concept to contact me through linked-in or email:
in particular I need to collaborate with companies active in CPV technology and architects who want to join in development of the system for realisation of the first project constructed based on the concept.

Planet Agent ( A crowd-sourced planet conservation project)

2010-12-15T11:01:00.003+01:00

Finally i could manage to Launch The Pilot program of Planet Agent website although I am not at all good in building websites(It is not my specialty by the way)

What is Planet Agent About?
It happens to many of us to pass by an unpleasant scene of destroying our planet, but not every one has the motivation, knowledge and resources to bring a civil action against this cases, but as a planet Agent we can report these kind of information by taking a photo or recording a video and uploading it to a website dedicated to environmental activists, to gather information from all over the world and process this information in relevant groups including environmental activists,scientists, lawyers and green politicians to investigate about the case, try to solve the problem by collaborating, and consequently if there is no other way rather than the court of law, to institute legal proceeding against the case as the final solution,

This participation in the first phase would be carried out by local contributers which are members of green Agent community. however this issues might escalate to a countrywide or worldwide concern as always there are local industries that resist against green laws & can't bear environmental activists.

After that pictures,videos and other information are uploaded to the website and located exactly on the map(By geotag technology or just manually as it is done in websites like panoramio.com,) person who has published the information, would add some initial suggestions that could be done about the case, other members of the community can propose other possible measure to be taken about the case or just confirm their availability for one of the choices which could be done to solve the problem. at the end, depending on the members availability, they would act in relative groups and it would be more efficient if the website be equipped with proper options for virtual gathering and video conference between them.

After the solving of problem, new pictures and videos would be added to case to show activities of green agents and to encourage other members and other people to be more actively involved in environmental issues.

Hopefully this can compensate insufficiency of governmental activities and investigation regarding environmental concerns and put more pressure on politicians of a region or country as large amounts of information(photos and videos of reporters) confirm a big environmental problem in their region.

Electromagnetic paper recycling system

2010-10-18T22:30:00.009+02:00

Concept of Electromagnetic erasing system is inspired from observation of destructive effects of electromagnetic radiation on color pigments. While ink & pigment producers try to increase resistance of pigments in prolonged exposure to sunlight, this project aims to utilize electromagnetic radiation in a fully controlled reaction inside a machine to break the bonds of color pigments that absorb only a particular range of electromagnetic spectrum. In order to have an efficient system only those CMYK pigments should be utilized that their absorption band is different from paper. In this case, in a similar way as a photochromic or thermochromic material, color pigments start to decompose into colorless products however in contrary to what we expect from a photochromic change, electro erasing would be an irreversible reaction.
This concept was selected among Designboom shortlisted entries(Seoul iida),

T-mate ( Travelers' instant interpreter)

2010-09-17T13:17:00.008+02:00

T-Mate is travelers’ personal instant interpreter; this device is able to interpret your voice from your mother tongue to any other language and vice versa. Using T-Mate, you need not to be worried about either your rusty English or your respondent ability of speaking English. Retain your identity and also let local people communicate with you in their own language.

PRO-STRAIGHT

2010-09-17T12:40:00.024+02:00

The fast pace of life requires one to quicken one’s pace. Every cyclist, even those who cycle for exercise, would rather have a lighter and a faster bike, but for commuters it is not just the matter of preference. Actually having a different bike may affect the user’s perception of a “long distance” in terms of time and energy consumption for commuting by bike. A human being can travel on a bicycle at low to medium speeds of around 10-15 mph (16-24 km/h) using only the power required to walk. PRO-STRAIGHT aims to achieve an average speed of 30 Km/h for exactly the same power... for a speed of 30 km/h almost 75% of effort required is order to overcome aerodynamic drag. Just by knowing this we can realise the importance of reducing the frontal area and setting a better air flow... W(aerodynamic drag) = p/2.Cw.A.V² P = air density Cw = drag coefficient A = frontal area V = speed. Less drag results in less effort, higher speed and longer commuting in the same period of time. Here is the question: “how far do you consider a long commute by bike?” would you consider 10 km as long a distance by bike if you could travel it by doing just less than half an hour of easy peddling?

See also : INFLATABLE FAIRING FOR BIKES

Inflatable fairing

2010-09-17T12:17:00.019+02:00

Inflatable Fairing is a design that aims to persuade bikers to use their bike on a daily basis, regardless of the weather. Depending on the location of a country on the earth’s surface, there are several months of the year during which there might be rain fall, snow or cold weather. This design is a lightweight temporary shield to protect the cyclist from the rain and the cold, with all the advantages of fairings, in addition to the fact that the user can always choose whether or not to use it. This particular shape is taken from the rain droplets and is especially designed for PRO-STRAIGHT bikes in harmony with the idea of an aerodynamic bicycle; yet it could be adapted for conventional upright bikes, recumbent bikes, velomobiles and motorbikes as well.
This concept was awarded the complimentary award of Seoul cycle design

Semi-Wireless Mp3 Player

2010-09-17T11:50:00.007+02:00

Semi-Wireless Mp3 player is a mp3 player which the player and its headphone has been integrated together in a compact way to facilitate using mp3 player by shortening headphone wire as much as possible. This mp3 player would be placed on one ear; it has one headphone integrated with the player body and another retractable headphone for the opposite ear. It has not been proved that wireless technology has side-effects on our body, but if we can use a normal mp3 player with all advantages of wireless technology, there would not be any reason for splurging on wireless Mp3 players.

REVO-DISH WASHER

2010-02-19T00:41:00.002+01:00

The design was developed based on a concept for facilitating loading and extracting the dishes from the machine, Not sure if we succeeded .
(In a team with Stefano Vescovo and Hamed Ebrahimian)

MEAT SLICER

2010-02-19T00:40:00.005+01:00

Hand function stimulated in a meat slicer, designed for Berkel as a university project(A team work by Sergio Marelli, Hamed Ebrahimian and me)

MODELING

2010-02-19T00:38:00.005+01:00

One month left to start my Masters in polytechnic of Milan (I had already resigned from my job), I got two separate offers to build gigantic models for fiber glass Molding:

First one was modeling of the roof of an observatory center (a semi-sphere of 12 Meter diameter) and they wanted it to be without any visible gap on the edge of separate slices,

The other project was a crown-shaped piece of fiber glass to be placed on a high-rise building for decoration.

Both projects were enough challenging to tempt me and my friend Hamed Ebrahimian to accept them.

We started to design a structural mesh in order to work gypsum on it and To have a precise sphere, we also designed a specific tool which was composed of a rod (6 meter long) with a scraper knife on the very end of it.

We did not have enough time to document the project but here are some pictures I took with my cell phone.

Building Crown:

Fiber glass piece installed on the building.

(cortesy of Jian Architecture)

work in progress

Gypsum Model for the roof of Observatory Center:

Here are some photos of the progress:

Mesh

The client expected such a smooth

surface while divided into 8 slices/modules

Using a rod of 6 meter length with a special scraper knife at very
end of it to make sure that we would have a precise spherical surface.

Even the Scrapper knife had the same radius of the sphere.

GRAB YOUR BEER GLASS

2010-02-19T00:36:00.002+01:00

NAZEM SCHOOL ALARM

2010-02-18T21:32:00.006+01:00

Meanwhile we were working on finding a market for POSTAL CD, we started a new project,
a device to control automatically bell rings of schools,
school deans still use bell to notice about lesson and break time, but if they do in manually there is always probability of forgetting or mistake.
this was a useful electronic device to adjust it one and use it for a whole year...we worked a lot on interaction design and also manufurability of it since it was ourselves who should pay for mold assemblage and everything...
Not havon a right marketing strategy and fund this project turned to be the main reason for our bankruptcy :D

I still like our logo: SHEEVEH

Postal CD

2010-02-18T20:45:00.013+01:00

At the very last year of bachelor study two friend of mine and I decided to start our business, this was result of our first try to make money from our ideas, Mini CD's had been just presented in Taiwan market, I ordered it and I used to utilize them for making a demo and catalog CD's for companies.

What if we make a combination of postcard and multimedia CD and include a post card with a auto-run multimedia mini CD full of music and pictures and screensaver? that was the idea and we made it... I prepared a number of 20 different postcards and multimedia Cd's . Subjects like flowers, Love, Valentine day, Fun, Pets, Monuments, etc... it was also a part of our promoting plan for our new born studio; despite our efforts it was not a commercial success though, since we were new to this market and distribution pathways and also existence of the mafia in the distribution systems.

I still Like our Logo: "SHEEVEH" which means: Appealing method in Persian

PC SPEAKER

2010-02-18T18:21:00.009+01:00

I don't have much to say about this... this project never went ahead the way i wanted, but in general i was so happy about that,first of all because it was my first real job in design while i was still a student and also because it was a great experience for me ,it was my first serious experience with a parametric 3d modeling CAD program, because company wanted to do the modeling by SLA Stereo-lithography method.(those days Autodesk Mechanical desktop was more common and i did it with that program)

we made 2 prototype of that.

I had this prototype for years as my speaker at home...

HANDS FREE HELMET

2010-02-18T16:30:00.012+01:00

It’s simple and inexpensive substitution for auto darking welding helmet which has been designed to be used while user need one of his hands be free.

This helmet is designed for welders who they need one of their hands to be free during and from beginning of welding process, when welder wants fix two or more work piece and starts welding; or when welder needs to see welding area right before beginning of welding to adjust where to start welding

HOW IT WORKS:

In this helmet there is a gap in front of welders eyes which he can see through this gap.

after fixing work pieces together and adjusting start point of arc welding; simply he needs to tilt his head downward and starts welding

This project was my first success story, I had this idea since i was a freshman in college, i worked on it and made a model by fiberglass, presented it to a company and they liked it, they didn't pay me anything but i was so happy about my first project being produced in second year of my study.

KEY-MOUSE(2000)

2010-02-17T20:15:00.010+01:00

While using your PC probably have felt that sometimes you like to lean on your chair but you simply can't , because you will loose accessibility to the mouse, so with keymouse you have two keyboard & mouse on your knee.

In this design, your mouse will never get out from mouse pad ! because it has a limited range for movement, this mouse is sensitive to force instead of movement while we have no changes in user functions.

PS: Those days(year 2000) the new generation of mouses have not been devised yet, so i was looking for a way to get rid of ball-mouses and mouse pad and also make user more comfortable at the desk)