Project Motivation, Needs and Goals

My name is Albert Hagan and I am a graduate mechanical engineering student. 

My interest lying in energy led me to do this project because its application involves the conservation of energy.

In this experiment, I am going to create a temperature-controlled system called Envivovent. This control system uses temperature sensors such as the DHT, thermocouple and the temperature resistor sensor to measure the temperature at different locations within the Envivovent. The goal of the project is to be able to control and study the temperature within different locations in the Envivovent using fans to cool the system via a relay channel and an Arduino control board. 

Applications of this system include greenhouses, industrial rooms and in in projects which apply temperature-controlled environments.

In order to model a system which is temperature controlled, we adopt a mathematical model form the zero dimensional energy balance equation. 

Project Background

The principles of first law of thermodynamics is applied to understand the energy changes in the system.  Next, we apply the zero-dimensional energy balance equation. The zero-dimensional energy balance equation enables us to come up with the parameters of the equation to analyze the system. The equations developed can be shown below:

Next, we also study the principles of the Psychrometric chart and incorporate that into the project. The psychrometric chart is a graph that employs the principle of using the humidity ratio and the dry bulb temperature to determine to determine the properties of air at a specific temperature.


Equations for studying the system. 

The above equation can then be converted to a first order ODE. This can then be solved using numerical methods.

Project Schematic and Sequence

The electrical connections ar

Materials Used

The materials used in this experiment are:



This is a basic lowcost temperature and humidity sensor. It uses a capacitive humidity sensor and a thermistor to measure the surrounding air, and output a digital signal.


The thermocouple is a temperature measuring device which measures resistance using voltage difference across its wires.


This contains 4 5v relays which interfaces microcontrollers and sensors. It can be used to switch multiple loads at the same time.

Learning Objectives

The project is designed to enable to student gain knowledge in the following areas:

  • Arduino Programming
  • 3D printing and CAD Modelling
  • A strong understanding of psychrometry and heating ventilation. 
  •  Electrical circuit connections and Electrical Schematics
  • Using PID controls to stabilize and optmize an HVAC system.

Project Vision and Narrative

The ultimate vision of this project is to enable the student to understand psychrometry, heating and ventilation to be able to control characteristic factors of a system.  This will then be used in modelling a building system to minimize energy loss.

Instructional Lecture 1: Project Overview

This video shows an overview of the project. It walks us through the various stages,  stating the current phase of the project and also the future directions in the next phase.

Instructional Lecture 2: Thermocouple Calibration

This video explains the calibration methods  used for thermocouples.

About the Author

My name is Albert Hagan and I am a first year master of science student in the MEMS department. My interest lies in the area of controls and energy. I had my undegraduate education at Temple University and I studied mechanical engineering. Prior to being a student at Duke University I worked as a project engineer, modelling land development plans for a civil engineering consulting firm.

Last updated May 2021