Steps towards sustainability: Energy generating swing ...

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Shaheed Zulfiqar Ali Bhutto Institute of Science and. Technology. Karachi, Pakistan. Abdul Raziq Khan Niazi3. Mechatronics Department. Shaheed Zulfiqar Ali ...

The 9th International Renewable Energy Congress (IREC 2018)

Steps towards sustainability: Energy generating swing ride Atif Saeed1

Daniyal Mazher Ezzi2

Mechatronics Department Shaheed Zulfiqar Ali Bhutto Institute of Science and Technology Karachi, Pakistan

Mechatronics Department Shaheed Zulfiqar Ali Bhutto Institute of Science and Technology Karachi, Pakistan

Abdul Raziq Khan Niazi3

Malik Muhammad Haris4

Mechatronics Department Shaheed Zulfiqar Ali Bhutto Institute of Science and Technology Karachi, Pakistan

Mechatronics Department Shaheed Zulfiqar Ali Bhutto Institute of Science and Technology Karachi, Pakistan

Wissam Amin5 Software Department Bahria University (Karachi Campus) Pakistan Abstract -- Theme Parks today have many different types of swings. Many of the swings have rotary and to-fro motion. These swings can be connected to an energy conversion system that harnesses the available mechanical energy when the swings are in operation. Being able to capture the available mechanical energy these parks could self-generate the required power for the park. In this paper, a fine small-scale model of a swing is made, it is connected to a system that converts mechanical energy to electrical energy. The measurements of different parameters are taken such as electrical power output, rpm and mean height at different weights. These measurements are used to assess the efficiency and the amount of electrical power that could be generated from the system. The results suggest that around 16% of available mechanical energy can be harnessed by these swings. This energy can be used to power the park partially or completely, lowering the operating cost of and making it an ecofriendly park Keywords: energy harness, renewable energy



Due to the shortfall, and rising costs of electricity in Pakistan, there is an increasing need of sustainable energy. In Pakistan a shortage of 5000 MW on average

978-1-5386-0998-9/18/$31.00 ©2018 IEEE

is experienced every year which leads to very long power outages in the urban and rural areas of the country having adverse effects on the economy [1]. According to the planning commission of Pakistan, due to the shortage of power and gas in 2011-12, a lossof 3 to 4 % was suffered by the GDP [2]. Due to the long and often unpredictable hours of power outages there is a need of alternative energy solutions, which are cost effective and sustainable. A growth rate of 1.9% in population of the country is expected at the end of 2017[3], therefore there is a high demand of energy which is growing about 9% annually [4]. The price of electricity supplied by the grid is also on the rise. The protection of environment is another reason for investing and working on ways to design and build energy efficient and eco-friendly places. In Pakistan the electricity is produced from three main sources which include hydel, thermal and nuclear. The thermal sources include gas and furnace oil. Making use of thermal sources for electricity generation have adverse effects on the environment as they release huge amounts of greenhouse gases [5]. A research report estimated in 2012 the emissions of greenhouse gases from the energy sector was about 45.8 % of the total emission [6]

It is a known fact that huge amount of electricity is wasted due to inefficient designs, that being so research is being conducted to get more and more efficient designs to minimize the electricity requirement as much as possible. In our project we have designed a prototype swing which is connected to a system that converts the available mechanical energy to electrical energy when it is in operation. The operation of the swing is analyzed and the efficiency is calculated. The sources of energy losses are investigated to help design a more better and efficient swing which could harness maximum amount of energy from the system. Literature Review Royal Boon Edam Group Holding designed, an energy harvesting revolving door, it is a modified revolving door consisting of energy harvesting system. It converts mechanical energy into electrical during operation. This was made for and placed at Driebergen-Zeist railway station in Netherlands. Each day on average 8500 people pass through the station, a calculation was made and found that for this particular situation around 4600 kWh per year power could be generated, this is a considerable saving compared to an ordinary entrance [7]. Mehdi Niroomand and Hamid Reza Foroughi designed and built an electromagnetic microgenerator. This microgenerator device is can be used to change human motions to electrical energy. The small size and use of a to and fro mechanism are two main features of the device. The generator can also generate electrical energy from minor vibrations. The device is analyzed by being installed to human limb during normal walking. The maximum generated electrical output during normal walking is around 416.6 μW. This power is sufficient for many small-scale applications [8]. Wei Wang, Junyi Cao, Nan Zhang, Jing Lin and WeiHsin Liao designed a magnetic-spring based on electromagnetic energy harvester to harvest energy from human movement. Ansoft Maxwell software was used for modeling the system [9]. Dynamic model of the device and system was made and corresponding theoretical analysis were performed to approximate the efficiency of the proposed system. Results derived from the experiment showed that the device is better to generate electricity for a broadband frequency range. During the experiment the device was attached

to the human lower limb and considering human motion, the impact between shoe and ground as well as the swing motion of leg were enquired. Results were analyzed under different motions and speeds, it showed that proper parameters of the structure such as mass and movement length can make the device more better and more energy could be harvested. Also, it is shown that the swing motion of human lower-limb could enhance the performance of the device, especially for greater speeds. Triboelectric nanogenerator is designed by FeiXing, YangJie, XiaCao, TaoLi and NingWang which changes kinetic energy available during human motion and endows sustainable operation of wearable electronics. They made a efficient and natural turboelectric design and documented it. This device is for harvesting slow walking energy. They have arranged their device in a way so that the ground and the human body are as electrodes of the triboelectric generator, during walking the rubber soles generate pulsed currents from the mechanical energy available when the sole is pressed against the ground these currents are alternative. The maximum open-circuit voltage and short-circuit current generated during the operation of the system were found to be about 400 V and 12 μA, respectively. This micro-generator is a very small and compact device. It is also simple to operate and hence this triboelectric generator can be attached into wearable gadget items that need very little energy to operate. This can be used to make battery less devices that harvest energy [10]. A rotational electromagnetic energy harvesting transducer was made. This transducer was integrated in a button and operated when this button was pressed; therefore, the mechanical energy during the pressing of the button was converted into electrical energy. This transducer is made up of different layers of planar coils integrated into a printed circuit board, hard magnets that were multipolar were used as a mechanical system for movement conversion. The energy harvesting transducer harvested a maximum energy of about 4 mJ at a load of 10 Ω. During the operation of the system it was observed values were 2V open circuit voltage and the maximum short circuit current 800.



A small-scale swing is constructed. The shaft of the swing is connected to a large gear that drives a small gear. The small gear is connected to a dynamo. The voltage and current are measured across the dynamo when the swing is in operation. A constant velocity is applied to the swing using a stepper motor. Different weights are applied on the swing and the rpm, voltage and current are measured and noted down against the applied weight.

An ammeter was connected in series with a resistor to measure short circuit current. Voltmeter at terminals was connected to measure the terminal voltages. A stopwatch was used to measure the time of one complete trial. There were three trials conducted. Each time a different weight was put on to the rod which was connected to the shaft. The motion of the swing was observed and instruments were used to measure the RPM, voltage current and time of the motion. The values were noted down in a table after every trial. III.

Servo Motor (constant velocity)


The results obtained were mentioned in a table, using the results different graphs were plotted to analyze the system and also note the change in system subjected to the change in mass. The results obtained are as follows:

Input Gear



Mass (kg)

Height (m)

Time (s)

PE (W)

1 2 3

0.01 0.02 0.03

0.121 0.121 0.121

10 10 10

0.00118 0.00237 0.00355

Output Gear



1 2 3

Mass (kg) 0.01 0.02 0.03

Shaft of Swing

V=RPM/60 0.66 0.65 0.64

Time (s) 10 10 10

KE (W) 0.00022 0.00042 0.00062


Fig. 1: Block Diagram

The servo motor is controlled by Arduino. Arduino is a microcontroller; an algorithm was developed for servo motor that would make the motor to rotate between specified angles at a constant velocity. An optical Tachometer sensor was used to measure the RPM of shaft, the optical tachometer operated by using Infrared beam reflection to calculate the rotary motion of any body. This is done by calculating time taken for one rotation. A reflective strip was attached to the rod which reflected the infrared beam to the sensor, the sensor was held in one position pointing at the mean position of the swing. A simple DC gear motor was used as a dynamo so that high voltages could be achieved at low RPM.


Test 1 2 3

Voltage (V) 3.1 2.7 2.4

Current (mA) 0.12 0.09 0.07

EP(VI) (w) 0.000372 0.000243 0.000168


Test 1 2 3

KE (W) 0.000222 0.000422 0.000624

PE (W) 0.00118 0.00237 0.00355

MP 0.001402 0.002792 0.004174



EP (W)

MP (W)

1 2 3

0.000372 0.000243 0.000168

0.001402 0.002792 0.004174

Fig. 4.

n (EP/MP) *100 26.53 8.7 4.02

Velocity vs Mass

It is observed that when we increase the mass there is a decrease in velocity of the swing. This is because the input power applied by the servo motor is constant, in real life however there will be an increase in velocity with increase in mass.

Different graphs were plotted and each graph was discussed as follows:

Fig. 4.

Fig. 2.

Fig. 3.

Kinetic Energy Vs Mass plot

Electric Power Vs Test

We observe in this graph after every test the electrical power obtained was in a decreasing order. This is because the electrical power generated depends upon the velocity of the dynamo. The velocity of the swing is decreasing with increasing weight hence the power produced by the dynamo is also decreasing.

Potential energy Vs Mass

From these graphs we observe that kinetic energy and the potential energy of the swing increases linearly with the mass.

Fig. 5.

Potential Energy Vs Kinetic Energy Vs Test

Here we see both the available PE and KE of the system during operation increases with increase the mass.

It is clearly visible the efficiency decreases with Fig. 6. increasing weight. This isEffeciency because Vs theTest electrical power depends upon the velocity of the system. Only by increasing the velocity we must get maximum electrical output and hence obtain efficiency. IV.


The experiment results obtained show that at an average 12.6% efficiency of the system can be achieved. The electrical power obtained directly depends upon the velocity of the swing. The efficiency could be enhanced by minimizing the frictional losses in the joints by applying lubricants.


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A notable amount of electrical power can be obtained by the swings present in the theme parks if they are designed smartly. Adaptations of these types of designs could help reduce operating costs, provide a clean energy and could also give freedom from having to buy electricity from the grid.

References [1]


M. Ashraf Chaudhry, R. Raza, and S. A. Hayat, “Renewable energy technologies in Pakistan: Prospects and challenges,” Renewable and Sustainable Energy Reviews, vol. 13, no. 6–7. pp. 1657–1662, 2009. M. Qasim and K. Kotani, “An Empirical Analysis of Energy Shortage in Pakistan,” Asia-Pacific Dev. J., vol. 21, no. 1, pp. 137– 166, 2014.