REAL LIFE APPLICATIONS

Several years from now all aspects of society will drastically change for the better, as technology advances so will other areas such as economic, political, and social. With all these factors changing there will be an environmental impact throughout all. This project allowed us to experience the role of an engineer and how they make devices and technology more efficient yet also environmental. Creating the thermos showed on a smaller scale what engineers consider when making something; they do research, test, troubleshoot, and re-test again. From making the thermos we learned about the first and second thermodynamics, this design and information could help apply to other inventions. The need for efficient devices is significant it creates a positive impact for the society, because it allows people to work more conveniently and life becomes more sustainable for them since technology is advancing.

HOW EFFICIENT ARE THE THERMOSES MADE TODAY?

Most thermoses during this age come with an efficiency of at least 90%,and usually can't exceed 100% efficiency because it doesn't go along the law of second thermodynamics. Which states that nothing can be 100% efficient because due to conversions between substances heat is lost. The flask of a thermos is made of a thin low thermal conductance material, the space is a vacuum filled so conduction doesn't occur, and the shiny interior outside and inside of the thermos is used to prevent radiation.

http://uk.answers.yahoo.com/question/index?qid=20111005104556AAfamnZ

HOW HAS THE MODERN DAY THERMOS CHANGED FROM PREVIOUS MODELS?

spacers which provide additional support between the two layers of a thermos were added to eliminate the impact of the inner flask being too heavy for the outer flask to hold its contents. Another improvement to the thermos includes vapor cooled neck to reduce evaporation from the flask.

WHICH MATERIALS WILL PROVIDE THE BEST INSULATION FOR THE THERMOS?

*Styrofoam : Since the air pockets are too small they are unable to make a convection current between substances.

All the isolated gas bubbles slow down the transfer of heat.

REFERENCE: wiki.answers.com, http://www.ehow.com/how-does_4898717_why-styrofoam-good-insulator.html

*A Cotton Sock:  Cotton is a good thermal insulator as it traps air and has only little pockets of holes that air can go through, and that makes heat transmit slowly.

 

REFERENCE::wiki.answers.com ›

*Steel wool:  Steel wool is a fair thermal insulator (thanks to the trapped air) 

 REFERENCE:amlloyd.appspot.com

*Duct tape:  It's not as conductive as metals, but a lot more insulated  than foam or fiberglass insulation. Probably about the same as wood.

 

REFERENCE:answers.yahoo.com ›

*Bubble Wrap:  Each bubble contains air inside , which is a very good insulator. Very little heat exchange occurs, so whatever is wrapped in the bubble wrap is kept at a more or less constant temperature.

REFERENCE:uk.answers.yahoo.com

*Plastic: Because it's also made up of small air pockets tightly packed together so that heat is lost very slowly.

http://wiki.answers.com/Q/Why_is_plastic_a_good_insulator_of_heat

*Rubber: Rubber is a very dense material which makes it a good heat insulator because the denser the material is, the tigher the atoms are. When atoms are tightly packed together they're a stronger bond, so heat can't escape.

http://answers.yahoo.com/question/index?qid=1006052112417

OVERALL ANALYSIS

[Click image to enlarge]

• Test 1 : Efficiency = 85%
• Test 2: Efficiency = 76%

We lost majority of our heat from around the bottle, this may be because of the insulators we choose. Less heat was being transmitted from the bottom, and that was because we had the support of the rice preventing the bottom part of the bottle from touching the outer layer. We could've improved our materials by looked at the heat capacity of each material so we could get an idea of how much they generally insulates. I would've changed some of the materials for future versions and do more testing/improvements so we could compare results with a thermos that has a better efficiency than ours.

Laws of thermodynamics are the principles that govern heat transfer and thermal energy. The first law of thermodynamics state that, "Energy can be transformed into another form, but can't be created or destroyed." If you were to experiment with volatile heat sources you could have seen that liquid forms into gas when the temperature rises. When you lift the lid off of the thermos, gas will come out because of the hot temperature making the liquid evaporate. If we look at the heat capacity of plastic  which is, c = 39.6K Jkg-1 K-1 we can find out how much heat is measured to heat up a gram of plastic, or any other material thus finding out if the heat source if volatile. The equation for relating heat energy to a specific heat capacity in terms of mass is; Q = m c ΔT.

• Q : Heat energy input or output of the substance
• m : Mass of substance
• c : Specific heat capacity
•  ΔT: Temperature differential

The second law of thermodynamics states that," In all energy exchange  if no energy enters or leaves the system, the potential energy of the state will always be less than that of the initial state."  or in other words no process can be 100% efficient because some energy will always remain in the form on thermal energy. An example of this would be when a car runs out of gas in the middle of the desert and will not run again until you walk 10-15 miles to a gas station and refuel the car. When energy exchange occurs some energy is transfer into thermal energy;  Our project is evidence that this is true, as heat can be felt (meaning it's not 100% efficient).

http://answers.yahoo.com/question/index?qid=20071215081939AALhW4z
http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookener1.html
http://wiki.answers.com/Q/What_is_plastic's_specific_heat_capacity

ANALYSIS [RESULTS OF TEST 2]

Time loss testing#2 of thermos (May 8, 2013)
Period of 60 minutes

Time	Temperature (fahrenheit)
10:25 am	71 degrees
10:27 am	70 degrees
10:29 am	69 degrees
10:31 am	67 degrees
10:33 am	66 degrees
10:35 am	65 degrees
10:37 am	64 degrees
10:39 am	63 degrees
10:41 am	62 degrees
10:43 am	62 degrees
10:45 am	62 degrees
10:47 am	61 degrees
10:49 am	60 degrees
10:51 am	60 degrees
10:53 am	59 degrees

10:55 am	59 degrees
10:57 am	59  degrees
10:59 am	58 degrees
11:01 am	58 degrees
11:03 am	58 degrees
11:05 am	57  degrees
11:07 am	57 degrees
11:07 am	57 degrees
11:09 am	56 degrees
11:11 am	56 degrees
11:13 am	56 degrees
11:15 am	56 degrees
11:17 am	55 degrees
11:19 am	55 degrees
11:21 am	55 degrees
11:23 am	54 degrees
11:25 am	54 degrees

Total efficiency of test#2 is 76%
Test#2 : 54/71 x100 = 76%

ANALYSIS [RESULTS OF TEST 1]

Time loss testing#1 of thermos (May 7, 2013)
Period of 26 minutes

Time	Temperature (Fahrenheit)
9:17 am	70 degrees
9:19 am	69 degrees
9:21 am	68 degrees
9:23 am	67 degrees
9:25 am	66 degrees
9:27 am	65 degrees
9:29 am	64 degrees
9:33 am	64 degrees
9:36 am	63 degrees
9:40 am	62 degrees
9:43 am	62 degrees
9:46 am	61 degrees
9:47 am	60 degrees

The total efficiency for the first test is 85%
Testing#1: 60/71 x100 = 85%