1. Control System Design
Group 003 Section 040
Kahlil Gedin and David Obasiolu
Advisor: Nicholas Vacirca
Abstract
This report outlines the process of building a control system to cool a canned beverage with a
peltier plate, a thermoresistor, and a National Instruments Data Acquisitions Board. Due to the
lack of time and resources this control system was not fully developed. As a result, a cooling
system was designed to cool a canned beverage over a large time period.

2. Introduction
Problem Overview
Have you ever wanted to cool a beverage and there was no ice. Either you had to drink
your warm beverage or put it in the refrigerator or freezer for about 20 minutes. With this
engineering 103 project this becomes no longer an issue. To address this problem a control
system using a peltier plate was designed to instantly cool a can of soda.
Many cooling systems are designed to cool a variety of items. For example, a refrigerator
is designed to cool meats, vegetables, dressings, and beverages. As a result, the fridge is designed
to cool a specific space, causing it take some time to cool a beverage. If a cooling system was
designed to cool specifically a beverage, the “warm beverage issue” would no longer be a
problem.
In this project a peltier plate, thermoresistor and National Instruments Data Acquisition
Board was used to build a cooling device.
Existing Solutions/
Related Work
Others have created similar cooling systems for controlled cooling and storage units.
Memmert has created a Peltier Cooled Incubator. The Incubator has multiple functions: stores
samples, controls ventilation, limits vibrations and noise, and uses peltier plates to heat and cool.
Also the stainless steel container is corrosion proof. This design has been used to solve storage
issues for pharmaceutical drugs and for food.
In addition, Tellurex has designed many thermoelectric devices. They have designed a
thermoelectric refrigerator, a medical device to control testing environments, and systems to
create electric power.
These are high power cooling systems that can preserve items and cool objects fairly
quickly. This is why these are used by many companies in the food and pharmaceutical industry.
However, their cost and power consumption is one of the reasons these designs have not been
bought for personal use.
Project Objective
The objective of this project was to build a prototype cooling system to cool a can of soda
as quickly as possible. In the process, a PID loop would be developed to best optimize this
2

3. process. This cooling system is different from Memmert’s and Tellurex’s because it cools a
specific area, not an entire chamber and it reads the temperature of the item it is cooling. This
allows the system to cool the item close to the desired temperature without overshooting the
temperature.
Technical Activities
Programming the Data Acquisition Board
The National Instruments Data Acquisition Board (DAQ) was programmed with Matlab
to function as a PID controller. The code to initialize the DAQ was copied from the script used in
the Engineering 101 Design Lab Module for the accelerometer. Then inputs were initialized to
receive voltages from ports 5 and 7 on the analog output side of the DAQ board. Then a function
was created to send voltages from ports 14 and 15 on the analog output of the DAQ.
The function we used to take input voltages was “getsample(ai)” and the function to
ouput voltages was “putsample(ao,5)”. The ai and ao are variables which hold the port number
and the 5 in the putsample code was the volts.
The loop of the system only consisted the proportional term. The value was set to .53. In
10 second intervals, if the input voltage did not match the desired voltage (corresponding to the
desired temperature of the beverage) then the output voltage was multiplied by a factor of .53 as
the input voltage approached the desired voltage.
Powering the Peltier Plate
The peltier plate was powered by the DAQ board but with the help of an amplifier. The
amplifier was needed to increase the voltage applied to the peltier plate. The DAQ could only
output 5 volts. The amplifier took in power from a DC power supply and a signal from the DAQ
board. The amplifier took in 2.5 volts as the offset voltage for the signal coming from the DAQ
and took in a positive and negative 25 volts from the power supply. This provided the peltier
plate around 1 to 2 amps.
3
Figure 2. A picture
of the amplifier

4. Unfortunately this amperage was to low to create the heat transfer desired to cool a
canned beverage instantly. The system could cool a beverage very slowly. The optimal amperage
for the cooling system to cool the can of soda instantly would be about 5 to 6 amps.
Designing the Temperature Sensor
The temperature sensor was created with a thermoresistor attached to a resistor. As
temperature changes the resistivity of the thermoresistor changes as well. Using a resistor with a
known resistance we could measure the voltage across the system.
This voltage would allow our system to know the temperature of the canned beverage. To
calibrate the sensor, the thermoresistor needed to be placed into water at different known
temperatures. This would pair up the voltages read across the resistor with temperature and
define that correlation.
Results/Future Week
The final deliverable was a cooling system without a temperature sensor. The cooling
system could cool a canned beverage over a long period of time. With more time the temperature
sensor would be calibrated to define the correlation between the voltage across the resistor and
the temperature of the beverage. Also, a new proportional value would be chosen to pick the best
control loop for cooling.
An extension of the project would be to include an integral and derivative term to create
the most efficient loop. Also, an area of research for the future is to analyze how to convert the
heat loss from the system to electrical energy, which could be resupplied to the system.
4
Figure 3. A
thermoresistor
attached to the
DAQ

5. References55
[1] Besançon, Robert M. (1985).The Encyclopedia of Physics,Third Edition.Van Nostrand
Reinhold Company. ISBN 0-442-25778-3.
[2] Tellurex.“Introduction to Thermoelectrics and Design Manual,” Internet: http://
www.tellurex.com/technology/design-manual.php 2010 [Apr. 16, 2012]
5