Paper -a Development System For Comfortable Umbrella(1).docx

비전공자를 위한 컴퓨팅사고 기반의 SW교육과정에 관한 연구 홍길순*, 이몽룡** *대한대학교 소프트웨어학과 **민국대학교 컴퓨터교육과 e-mail : [email protected], [email protected]

A Development System for Comfortable Umbrella Hakiki1, Hakim Khaula Nurul2, Nugroho Yuniarto Wimbo2, Liu Hao1 1Dept. of Mechanical Engineering, Keimyung University 2Dept. of Electronics Engineering, Keimyung University 요 약(Abstract) In the Summer season often have come heat wave, and temperature will increasing to be 42 0 Celcius. In the other hand, the heat wave can triggered heat stress in a human, with the result that an umbrella is needed that is quite comfortable to use during the Summer season. Therefore in this project have purpose to development comfortable umbrella for using in the Summer, this is contains electronics system and mechanical system. The solar cell will be use for source power for charging battery, electricity from the solar cell will be increased on the power supply regulator to get the desired voltage to charge the battery. The voltage needed for charging battery is 8.82 V, and have charging time equal 1 hour 41.58 minutes. On the other hand, voltage from battery wil be use for dc motor fan, led and charging mobile phone with average load power around 7.56 Watt. The battery have capacity around 3200mAH, with the result that time performance system will works around 3 hours 13 minutes. The different of comfort parameter of airflow velocity can be felt everyone. the airflow velocity felt adequately when there is no sweat. The airflow velocity selected between 5 m/s – 10 m/s, so that the maximum required power is 9 watt. Keywords:

1. Introduction One of the main problems in summer in Indonesia is heat wind. It is a sultry weather and make people uncomfortable when the do some activity outside. When the heat wave comes, the temperature will increase to 42-degree Celsius. People must use something to protect themselves from sunlight such as an umbrella. In addition to providing good effects, heat wave, as renewable energy, can also be used to generate energy by energy producer to minimize the adverse effects of high temperature. Through solar cells, solar energy can be converted into electrical energy.

Therefore, this paper purpose design an umbrella by using a fan, to provide wind flow and reduce temperature. The umbrella include several solar cell and rechargeable battery to save power for usage when sun is weak. In this design, the fan will be placed in the edge of the umbrella frame, and then when the umbrella to be close, the blades of the fan will be folded. On the other hand, a battery and electronic control system will be placed on the handle of the umbrella. 2. Design of System 2.1 Design

The solar panel adhered to cloths of the umbrella is a main resource in this system which produces power to turn on a fan that installation frame of the umbrella. A switch button is required to set up to control the fan on or off. The fan is driven by a 5V DC motor. This is enough to provide the airflow. Besides, the solar panel is to charge 8.4 V battery when sunshine is available. In order to increase the performance of this system, the fan will be driven by power of battery when the sun does not appear. The battery is installed in handle of umbrella. Charge/discharge controller is used among the solar panel, the battery, and load to regulate the output voltage and to protect the battery from overcharging. Overcharging a battery will cause to explode, causing to harm the system. The figure shows schematic of the system work.

Figure 2. Battery level indicator circuit

Figure 3. Schematic of charging circuit

Figure 1. Schematics of the system 2.2 Design of Electronic Circuit One of the most challenging tasks of this system is to design and implement an electronic system for charging external units such as battery in order for the user to benefit from the power generated from solar energy. An electronic system is needed to control these two processes. Consequently, the control system requires two main circuits: power distribution circuit and battery charging control circuit. There are some designs of an electronic circuit for battery, including battery level indicator, electronic circuits of charging and discharging system. these schematics are shown in figure 2, 3 and 4.

Figure 4. Schematic of the discharging circuit The electronic circuit, using generally available low-cost components, is very simple, safe, and economical. The typical target voltage of a 2S LiPo battery is usually 8.4 V (note that target voltage is not the same as the nominal voltage, which is 7.4 V typical), and LiPo battery requires a special type of charging mode that uses the CC/CV method (constant current/constant voltage) with 1-C charge grade (1 A for a 1,000-mAh battery). However, charging at a lower than 1-C rate is perfectly safe and will not damage any battery. The design is optimized for batteries of 1,000mAh or higher, and the input power source can be any linear/switch-mode power supply capable of catering an output current of minimum 1,500 mA at 18 V. Normally, a LiPo battery connected to this circuit will be charged to 95% of its nominal voltage within 60

minutes and charged up to 100% of its target voltage within two hours thereafter. The electronic part are, in fact, a perfect blend of one constant current source and one constant voltage source built around the popular adjustable three-pin voltage regulator LM317T (IC1 & IC2). Here, IC1 and R1 set the output limit current while IC2, R2 and P1, set the regulated voltage output. Related capacitors (C1–C2) are used to increase circuit stability by reducing unwanted noise. The rest of the electronic part one a bunch of visual indicators and their supporting components. LED1 (amber) is the “power/battery-connected” indicator; LED2 (blue) is the “current flow” indicator, and LED3 (red) is the optional “battery-charged” indicator. The entire circuit can be constructed on a small PCB. Both ICs must have heat sinks, and the TO-220 heatsinks should be isolated from other components of the circuit. After construction, feed 18 V to the circuit through DC_IN jack (J1) and adjust P1 to get precisely 8.4 V (±0.02 V) at the VBAT rail. For the solar energy, the panels are to be attached on umbrella using covered solar panels. The voltage required more than 8.4V to provide power for all, so the panels were installed to fix 6 units which contain 1.6 volts for each unit. Every unit will be put on each segment on the umbrella. 3. Performance Calculation 3.1 Charge and Discharge Performance From Figure 3 can calculation of output voltage for charging battery LiPo 7.4V/3200mAH, in the previous discussion, battery charger must have a voltage higher more than the voltage of battery so the design of charger around of 8.4 V. Output voltage from regulator can be calculated by Equation (1) 𝑉𝑜𝑢𝑡 = 𝑉𝑟𝑒𝑓 ∗ (1 + Vref R1 R2

𝑅2 𝑅1

Figure 5. Simulation output from charger

Figure 6. Simulation output current from charger In Figure5. the simulation show the voltage output is 8.92V a little bit different from the above calculated result as 8.82V. And then V-out is used to charge the battery Lithium with capacity 3200mAH and 7.4V. For time charging of battery it can be calculated by the following equation. 𝑩𝒄 𝑻𝒄 = ( ) ∗ 𝟔𝟎𝒎𝒊𝒏𝒖𝒕𝒆……………… (2) 𝑰𝒄 Tc = Time for charging Bc = Battery Capacity Ic = Current from charger The calculation shows that the completed battery is 101.58 minute or 1 hour 41.58 minutes. After battery fully charged it can run until battery low, it can estimate for how long battery use for running system. The calculation equation is in below equation.

) …………………… (1)

= 1.25 V = 330 ohm = 2K ohm

𝑹𝟐 ) 𝑹𝟏 𝟐𝟎𝟎𝟎 𝑽𝒐𝒖𝒕 = 𝟏. 𝟐𝟓 ∗ (𝟏 + ) 𝟑𝟑𝟎 𝑽𝒐𝒖𝒕 = 𝟖. 𝟖𝟐 𝑽 For verification this equation build simulation for this design. In this simulation V-out has little bit different between calculation value. The simulation result is shown below in Figure 5 and 6. 𝑽𝒐𝒖𝒕 = 𝑽𝒓𝒆𝒇 ∗ (𝟏 +

𝑷𝑩𝒂𝒕𝒕 = 𝑪𝑩𝒂𝒕𝒕 𝒙 𝑽𝑩𝒂𝒕𝒕……………………………………(𝟑) 𝑷𝑩𝒂𝒕𝒕 = 𝑷𝒐𝒘𝒆𝒓 𝑩𝒂𝒕𝒕𝒆𝒓𝒚 𝑪𝑩𝒂𝒕𝒕 = 𝑪𝒂𝒑𝒂𝒄𝒊𝒕𝒚 𝒐𝒇 𝑩𝒂𝒕𝒕𝒆𝒓𝒚 𝑽𝑩𝒂𝒕𝒕 = 𝑽𝒐𝒍𝒕𝒂𝒈𝒆 𝑩𝒂𝒕𝒕𝒆𝒓𝒚 The equation have result of power battery around 23.68Watt/hour. Moreover, from motor datasheet load of motor systems equal 7.56 Watt with the result that can calculate time performance of battery was running motor for fan. The calculation will be shown in this below equation. 𝑷 𝑻𝑷𝒆𝒓𝒇𝒐𝒓𝒎𝒂𝒏𝒄𝒆 = 𝑩𝒂𝒕𝒕 …………………………. (4) 𝑷𝑳𝒐𝒂𝒅

𝑻𝑷𝒆𝒓𝒇𝒐𝒓𝒎𝒂𝒏𝒄𝒆 = Time performance of Battery 𝑷𝑳𝒐𝒂𝒅 = Power of load (motor)

3.2 Performance of Airflow The law of energy conservation states that energy can not disappear and it is only converted from one form to another form. For instance, the electric power transform the energy of fan become kinetic energy of airflow. The shaft torque applies to the fan, and then the rotation of fan generates airflow. The system fan work will be shown in this picture below.

Power Versus RPM 25

Power (watt)

It is having result from the calculation of time performance is equivalent 3 hour 13 minutes, it means the system fan can run using power from battery at least 3 hour.

20 15

10 5 0 0.0

2000.0

4000.0

6000.0

RPM Figure 8. Result Power to RPM In the Figure 8 above, it shows that the change of RPM of fan linearly determined by the power necessary.

Figure 7. Fan work systems The mechanical efficiency (η) of a fan is the ratio of the rate of increase of the mechanical energy of the mechanical the power input. The mechanical efficiency of a fan can be written as follows 𝜂=

𝑊𝑜𝑢𝑡 𝑊𝑖𝑛

=

𝑃𝑜𝑢𝑡 𝑃𝑖𝑛

=

𝑚̇ 𝑣 2 𝑃𝑖𝑛

…………….(5)

Where Pin is as power input in watt. In this case, the efficiency selected between 0.6 - 0.7. The mass flow (𝑚̇) is defined as airflow through fan can be written as follows 𝑚̇ = 𝜌 𝑣 𝐴…………………………(6) Where ρ = density ( kg/m3) , v = velocity airflow (m/s) and A = cross-section area of circle of fan (m2) The interconection between the torque of fan (τ) in N.m, the angular velocity and the power supplies (P) in watt, determined as follows 𝑃 = 𝜔 𝜏 = 𝜋. 𝑛. 𝜏/30……………………(7) The angular velocity can be written in RPM (revolution per minute) as n 3.3 Result Performance Airflow Fan

Airflow Velocity (m/s)

Power versus velocity 12 10 8 6 4 2 0 0

5

10

15

20

25

Power (watt) Figure 9. Result Power to airflow velocity In the Figure 9 above, it shows that the choice of airflow velocity fixed depend on the power capacities supplied. The great of airflow velocity required, so that it needed the big power.

Velocity Flow versus RPM Fan

12

Airflow Velocity (m/s)

10 8 6 4 2 0 0.0

1000.0

2000.0

3000.0

4000.0

5000.0

6000.0

RPM Figure 10. Result of velocity flow to RPM fan In the Figure 10 above, it shows that the change of the airflow velocity to the angular velocity of fan seemed exponentially. The big angular velocity of fan, it can enlarge vibration and noise make uncomfortable. 4. Conclusion The prototype that was built contains all of the options that will be available, though different models of the Smart Umbrella will also be available to increase sales in different sections of this market. To provide a portable umbrella that could be used in any situation a solar panel array was built from individual solar cells to provide a means to power the design. A high-powered storage battery was also be used for this purpose when the solar panels do not provide enough power to run the umbrella fan. To increase the efficiency a Maximum Power Point Tracking synchronous switching regulator was utilized to maintain maximum power output to the battery charging system and the load.

Reference [1] McFarland, E.W. (2014) ‘Solar energy: setting the economic bar from the top-down’, Energy and Environmental Science, Vol. 7, No. 3, pp.846–854. [2] Paul El Khoury, Yara Saadeh, Charbel Azzi, Samer Bu Jawdeh and Ramsey F. Hamade " EcoBrella: prototype development of the umbrella as harvester of solar and wind energies ", Int. J. Sustainable Manufacturing, Vol. 3, No. 3, 2014. [3] University, Battery. "Advantages and disadvantages of different types of batteries", http://batteryuniversity.com/learn/article/whats_the_b est_battery