Energy Harvesting System using PELTIER Sensor with IOT

Transcription

1 Energy Harvesting System using PELTIER Sensor with IOT A.Abinaya 1, J.Arockia Kirijan 2, K.Manikandan 3, M.Ramya Electrical and Electronics Engineering, S.A Engineering College, 4 Assistant Professor, Electrical and Electronics Engineering, S.A. Engineering College 1 abi.abinaya.ash@gmail.com, 2 kirijan.kjv@gmail.com, 3 manikandansow1793@gmail.com Abstract-- About 80% of the world s total energy is obtained from heat energy. In the process of energy harvesting most of the energy is being wasted due to inefficiency in the heat absorption process. The presented work is oriented for thermo EMF generation from the wasted heat energy. This is accomplished by using PELTIER Sensor which absorbs the heat being wasted. The monitoring and control of the energy supplied by the harvesting system is done by with the help of IOT. The obtained energy from PELTIER Sensor is boosted up to a required voltage level using a DC to DC Boost converter. The design of Power Electronics Boost converter circuit with the use of open loop scheme needs modeling and then simulating the converter using the modeled equations. This can easily be done with the help of state equations and MATLAB/SIMULINK as a tool for simulation of those state equations. The monitoring process keeps track of the generated energy and utilized energy which in future can be used for analysis and integration of the system. Index terms Energy Monitoring and Control, IOT, Low Power Energy Harvesting, PELTIER Sensor, Boost Converter. 1. INTRODUCTION Thermo Electric Modules (TEMs) are effectively heat pumps that transfer heat from one side of the module to the other when a current is applied. This phenomenon is called the PELTIER effect. The goal of this project is to utilize this phenomenon to build a temperature controlled environment free of vibration and meet all the project requirements. Before making decisions on which components to use for the box, theory had to be reviewed and some preliminary calculations performed. PELTIER Devices, also known as thermoelectric (TE) modules, are small solid-state devices that function as heat pumps. A "typical" unit is a few millimeters thick by a few millimeters to a few centimeters square. It is a sandwich formed by two ceramic plates with an array of small Bismuth Telluride cubes ("couples") in between. When a DC current is applied heat is moved from one side of the device to the other - where it must be removed with a heat sink. The "cold" side is commonly used to cool an electronic device such as a microprocessor or a photo detector. If the current is reversed the device makes an excellent heater.. They are not meant to serve as room air conditioners. They are best suited to smaller cooling applications, although they are used in applications as large as portable picnic-type coolers. 1.1 Passive heat load The passive heat load for the unit was first calculated based upon a 25cm x 25cm x 25cm interior volume. Two inches of polystyrene insulated was assumed (k=0.027w/mk). Also included were a rubber seal on the door which was 50 cm 2 in area. (1) q tot k ins T k x rubber T x Where: q tot is the heat transfer in watts, k ins is the resistance to heat transfer, and k rubber is 0.014w/mK ΔT is assumed to be 20 C and Δx is 0.50m. This gives a q tot of 10 W. 1.2 Active heat load The active heat load is the equivalent of the cooling power that the unit will need to provide when the sample at room temperature is placed in the container. It was decided that one liter of water at room temperature would be the test sample for which all calibration and calculations would be made. The time to cool this load from 25 C to 5 C was determined to be 1 hour, or 3600 seconds. Based on these values: Q c m T p If the Cp of water is 4.14 KJ/kg*K, then Q = 82800J and dividing by 3600s to get power (W), Q dot = 23 W for the active heat load. Therefore, the total load is W = 34 W of power required. This assumes that there is no thermal resistance between the sample and the air in the unit. This may be an incorrect assumption but it does overestimate the cooling load. For the last few years, energy harvesting using PELTIER Sensor is being increased due to its rugged operation and (2) 656

2 reliable performance. The heat energy which is not being used in the process of energy conversion is absorbed by the PELTIER Sensor and is converted into electrical energy. The output of PELTIER Sensor is dependent on the difference in the heat between the surfaces. The energy which is harvested by the PELTIER module is connected to the load through a relay. The relay is used for controlling the supply of energy to the load. The system is connected to IOT through a microcontroller for monitoring and controlling. The microcontroller controls the relay switching functions. System modeling is probably the most important phase in any form of system control design work. The choice of a 2. BLOCK DIAGRAM circuit model depends upon the objectives of the simulation. If the goal is to predict the behavior of a circuit before it is built. A good system model provides a designer with valuable information about the system dynamics. Due to the difficulty involved in solving general nonlinear equations, all the governing equations will be put together in block diagram form and then simulated using MATLAB S SIMULINK program. SIMULINK will solve these nonlinear equations numerically, and provide a simulated response of the system dynamics. Figure.1 Block diagram of the energy harvesting system using PELTIER sensor with IOT 2.1 Block diagram explanation The PELTIER module absorbs the heat energy and converts it into the electrical energy. This electrical energy obtained is boosted up using a boost converter to a required voltage level. The output from the boost converter is fed through a relay to the load in which the relay is used to control the functioning of the load. The relay is controlled by a microcontroller. The microcontroller is used to interface the system to the IOT for monitoring and control for which the data from the system is acquired and shared with the devices connected through the IOT. The frequency of operation of the microcontroller is determined by the frequency of the crystal oscillator connected to it. The precise frequency generation is not possible using RC oscillator so a mechanical resonance from a piezoelectric crystal is used. 3. CIRCUIT DIAGRAM 657

3 Figure.2 Circuit diagram for energy harvesting system using PELTIER sensor with IOT. 3.1 Circuit diagram explanation The power supply of 230 V, AC is used as input for microcontroller. The 230 V supply is stepped down and rectified using a bridge rectifier. The rectified output is used for powering the microcontroller after being regulated as 5V DC by a regulator. A crystal oscillator of 16 MHz is connected to the microcontroller and is used for triggering the microcontroller. The output from microcontroller is used as impulse for drive circuit of DC to DC converter for driving the MOSFET. The output from port B of the microcontroller is used as impulse for drive circuit. TLP 250 IC is used as drive circuit for DC to DC convertor. The optocoupler in the drive circuit is for converting the signals from microcontrollers into signals for controlling ON-OFF time of the switch in DC to DC converter. The output energy from PELTIER Sensor is boosted up using the DC to DC converter. The voltage level of the converter output depends on the on-off time of the switch which in turn is dependent on the signal from the microcontroller which is converted into pulses at the drive circuit. The output from the converter is used for supplying a load through relay. The data are uploaded to the cloud from the microcontroller. The DC to DC converter is used to step up the level of input voltage to a desired voltage level. It consists of a supply, storage element, switch and a filtering element. The storage element can be an inductor or a capacitor. A diode is connected between the output and the filtering element. The diode is used to maintain the direction of flow of current. The converter uses a MOSFET as switch. The switch is driven by a driver circuit that controls the ON time and OFF time of the switch which controls the output voltage level of the converter. In this circuit, inductor is used as an energy storage element and capacitor is used as filter for removing ripples. When the switch is in ON condition, the current flows from supply to inductor and the switch. The energy is stored in the inductor. When the switch is in OFF condition, the current flows from supply through inductor, diode, and load. The inductor discharges the energy. The energy from the inductor is added along with the supply voltage and leads to the increase in the output voltage level. The diode is used to maintain the direction of flow of current so that the current flow in the load is in same direction. 4. SIMULATION CIRCUIT 658

4 Figure.3 Circuit diagram for simulation of DC to DC convertor 5. HARDWARE DESCRIPTION 5.1 PELTIER Sensor The PELTIER Sensor works on the principle of thermoelectric effect. When heat energy is supplied to the PELTIER Sensor, the charge carriers are moved by utilizing the energy absorbed. The charge carriers in the material diffuse from hot surface towards the cod surface resulting in the flow of current. The output from the PELTIER module depends not only on the thermoelectric effect but also on the gradient of heat absorbed or difference between the temperatures on the surfaces of the module. 5.2 DC to DC convertor: The DC to DC convertor used here acts as a boost converter for increasing the voltage level of the output obtained from the PELTIER Sensor. The converter consists of a switch, an energy storage element and a filtering component for removing ripples. When the switch is in ON condition, the energy is stored by the energy storage element. When the switch is in OFF condition, the energy stored by the element and the energy from the supply side are obtained at the output. The switch is driven by a driver circuit which controls the on and off time of the switch thereby controlling the output voltage level from the converter. 5.3 Battery The battery is used to store the energy from the boost converter. It supplies energy to the microcontroller when the PELTIER Sensor is not able to supply the energy. The energy boosted up from the PELTIER Sensor is stored in the battery and then utilized for supplying the load. 5.4 Relay The relay is an electromechanical switching device used for regulating the supply to the load. The relay is switched on and off through the microcontroller which is interfaced with the IOT. 5.5 Crystal oscillator 659

5 A crystal oscillator is used for creating an electrical signal with precise frequency which can be done by using a mechanical resonance of a vibrating piezoelectric crystal. This crystal oscillator is externally connected to the microcontroller to supply the frequency signals required for operation of the controller. The value of the capacitance used in the oscillator determines the stability and start up time. 5.6 IOT Interface Internet of things interfaces devices with vehicles using electronic Sensors and the internet. Internet of things connects physical objects like devices, buildings and other items embedded with electronics, software, Sensors along with network connectivity that results in collecting and exchanging information among themselves. In this system the things in internet of things refers to the PELTIER Sensor, load and relay. The microcontroller collects information from the things and updates it with the webpage created for monitoring and controlling the system with the help of this IOT interface. 5.7 Microcontroller The Microcontroller is used to interface the system with IOT. The microcontroller used in this work is an 8 bit microcontroller with flash memory and analog comparator. It is a 40 pin package with 5 ports (33 I/O ports). It has three communication protocols namely, USART (universal synchronous/ asynchronous receiver/transmitter), I2C (interintegrated circuits), SPI (serial peripheral interface). The data like energy generated by PELTIER Sensor, status of the load and control signal for relay are communicated through microcontroller. 6. EXPERIMENTAL RESULTS Figure 4 Simulation result for converter output voltage The simulated result of the output voltage obtained from the DC to DC converter is shown in the fig 4. It shows that the output of the converter increases exponentially upto a specific value and then increases gradually. 660

6 Figure 5 Simulation result for converter output current The simulated result of the output voltage obtained from the DC to DC converter is shown in the fig 5. From the simulated result it is observed that the current of the converter increases exponentially and then gradually from a specific level. 7. CONCLUSION The waste heat energy is efficiently converted into useful energy with the help of PELTIER module. The proposed system can be implemented at places that cannot be often accessed for monitoring and controlling. The data from the system are automatically kept track and maintained in a separate cloud that can be accessed from anywhere and can be used for analysis and integration of the system. The data from the cloud can also be used for controlling the system. 8. REFERENCES [1] Anagha Jamthe and Dharma P. Agrawal, Approaches for Energy Harvesting and Power Management in Wireless Healthcare Sensor Networks, presented at International Journal of Computer and Communication Engineering on September [2] L. G. dos Santos, EMBRAER perspective on SHM introduction into commercial aviation programs, in Proc. 8th Int. Workshop Struct. Health Monitoring, Stanford, CA, USA, 2011, vol. 11, pp deployed for large aircraft in-flight tests, Renewable Energy Power Quality J., no. 6, pp , Apr [5] R.Montheard, S. Carbonne,M. Bafleur,V. Boitier, J.M.Dilhac, X. Dollat, N. Nolhier, E. Piot, and C. Airiau, Proof of concept of energy harvesting from aero acoustic noise, in Proc. PowerPiezo Electric Plate,Atlanta, GA, USA, 2012, pp [6] D. Meekhun, V. Boitier, and J. M. Dilhac, Charge and discharge performance of secondary batteries according to extreme environment temperatures, in Proc. IEEE 35th Annu. Conf. Ind. Electron. Soc., Porto, Portugal, Nov. 2009, pp [7] Rohit Sharma, Vivek Kumar Sehgal, Nitin, Abhinav Thakur, Adnan Munir Khan, Ashish Sharma, and Pankaj Sharma, peltier effect based solar powered air conditioning system, presented at International Conference on Computational Intelligence, Modelling and Simulation on 2009 [3] Ultra electronics aircraft systems. (Jul. 2010). [Online]. Available: [4] D. Meekhun, V. Boitier, and J. M. Dilhac, Design of a solar harvester system for a wireless Sensor network 661