Abstract
Excessive Heat Exposure can pose significant health risks to individuals, especially when they are left in a car. Young children specifically are at risk since a child’s body heats up three to five times faster than an adult’s. When a child’s internal temperature reaches 104 degrees Fahrenheit, major organs begin to shut down, and when their temperature reaches 107 degrees, the child can die.
Wet Bulb Conditions are the measurement of Humidity and Temperature and Regards to how well humans can cool themselves by sweating. Different combinations of humidity and temperature can interfere with the human ability to cool itself in the process of sweating, which can eventually result in organ failure if the individual remains in the environment for too long. With Temperatus, we intend to create an automated cooling device that will initiate when surrounding temperatures reach a certain temperature, therefore cooling the environment well before dangerous temperatures can occur.
What is the problem?
On average, 37 children under the age of 15 die from heatstroke in a hot vehicle every year. This is not an implication of parental neglect, but simply a cautionary reminder of the possibilities of children being forgotten in vehicles. This can happen due to parent’s busy or changing work schedules, or even just forgetfulness. Temperatus is designed to automatically turn on when the interior of a car reaches a certain threshold and decrease temperature as well as relative humidity in the event that a child is left in the car to prevent overheating, heatstroke, and even death.
Design Alternatives and Rankings
Thermoelectric Cooler
- We chose this specifically because of its reliability in the sense that it’s long lasting, there are no moving parts so there’s less risk of it breaking, and it’s charged with DC current so that we could make it sustainable through solar panels
Dyson like fan
- We liked the idea because of the bladeless design, but ended up scrapping it because it would be difficult to integrate into a car
Fan with a mister
- We abandoned this idea because it would only worsen the humidity within the car
Design Criteria and Objectives
- Lowers the risk of heat stroke: Brings temperature below 104 F in under 15 min
- Durable to Heat: Melting points of all materials are greater than 150 F
- Portable: Can move from car to car, convenient
- Low maintenance: Minimal user input – as autonomous as possible
Design Evolution
Thermoelectric cooler
As the main component of our cooling device, the thermo electric cooler utilizes the peltier effect as 2 different semiconductors produce an extreme cold and hot side. Heat sinks are then attached to the two sides to help maximize these temperatures. 2 large fans are screwed into the large hot air heat sink to help dissipate the air to prevent the device from overheating as well preventing any damage to the module. 2 smaller fans are then screwed onto 2 small cold air heat sinks to help expand the air throughout the car.
Prototype 1
We started by testing a single thermoelectric unit to see just how effective this device would be so we could improve upon it and make any necessary adjustments. We used a bin to model the car where we placed a temperature and relative humidity sensor to help extract the data. Other materials utilized were also a laser cut lid specifically designed to accommodate the cold air heat sink as well as a 3D printed tube for ventilation
- Experiment Results: in 5 minutes, the temperature dropped from 110 F to 105.4 F, averaging about .92 degrees/min
- Goal for next prototype: Proposed to design a better ventilation system with a new 3D printed tube with a fan attached to the end to maximize the amount of hot air escaping the bin.
Prototype 2
What changed: We used a different thermoelectric cooler that had double what the original had assuming that it would produce better results, meaning we also had to laser cut a new lid to accommodate the 2 cold air heat sinks
- Experiment Results: the temperature inside the bin either remained stagnant or increased through the duration of the experiments, and additionally the female plug connecting all the wires and the power supply overheated
- Realization: The new ventilation system was the main issue because it wasn’t allowing the cold air to remain in the bin for long enough to change the temperature
- Goal for next prototype: Create a more restrictive ventilation system, and find a more powerful power supply
Prototype 3
What we changed: We found a better 12 volt power supply to replace the female plug that overheated, and then 3D printed a new vent that was designed with a hole for the arduino chip to fit inside in order to college the temperature and relative humidity. We also changed the experiment time period from 5 minutes to 10 minutes just to get a bigger picture. In addition to the adjusted trial time, we wedged copper strands throughout the cold air heat sinks to act as a condenser because of its heat transfer efficiency, its cost effectiveness, and its durability.
Experiment Results: In 10 minutes, the temperature went from 87 F to 73.1 F. So it was a 13.0 F decrease.
Goal for next prototype: Achieve an even greater temperature drop
Prototype 4
What we changed: For the final prototype, rather than weaving copper strands into the cold air heat sinks, we placed entire copper strands between the rows within the cold air heat sinks. Along with that, we also smeared them with thermal paste due to its high conductivity
Experiment Results: In 10 min, the temperature dropped from 119 F to 96.7 F, so it was a 22.3 degree drop With these results we’ve decided to stop testing and assemble the final prototype
Arduino
We coded an arduino, a powerful microcontroller board, to automate the activation process of our device as well as create an alert system as an initial measure. We used a temperature and relative humidity sensor to record the temperature and relative humidity of the ambient atmosphere and coded the arduino to turn on the device once the sensor recorded a temperature higher than 95 F or a relative humidity higher than 50%. For the alert system, we coded the arduino to turn on an alarm to sound and an LED to flash once the temperature and relative humidity sensor recorded dangerous conditions.
Car Integration
We want the device to be easily detachable so that it can move between cars. For specific orientation, the device will be pointed directly at the backseat to maximize efficiency, which means that the device will be placed on top of the middle console
Final Product
We laser cut a lid to keep the top of the thermoelectric cooler in place, and we attached a 3d printed tube to the cold side to help direct the air and allow it to funnel out into the car as well as a 3D printed mesh for ventilation.
Project Video
Future Goals
With more time we would…
- Connect Temperatus to solar panels to make it sustainable
- Motion Sensor: Indicate whether or not there is an individual in the car if it doesn’t need to be turned on
- Make it adjustable to more scenarios: What if there’s multiple kids in the backseat? What if there are kids in the very back of the car? Etc…
- Advance the alarm system: Developing an app to alert parents, or an automatic 911 contact if device is initiated
- Better car integration: how to maximize the extraction of hot air (window, connecting to car vent system
Sources
- https://www.theguardian.com/science/2022/jul/31/why-you-need-to-worry-about-the-wet-bulb-temperature
- https://www.electracool.com/moduleworking.html
- https://extension.psu.edu/psychrometric-chart-use
- https://www.britannica.com/science/climate-meteorology/Relation-between-temperature-and-humidityhttps://www.britannica.com/science/climate-meteorology/Relation-between-temperature-and-humidity
- https://interestingengineering.com/innovation/2d-device-keep-quantum-computers-cool?utm_source=linkedin&utm_medium=article
- https://www.nhtsa.gov/child-safety/you-can-help-prevent-hot-car-deaths
- https://www.consumerreports.org/cars/car-safety/hot-car-fatalities-year-round-threat-to-children-pets-heat-stroke-a2015990109/
Meet the Group!
