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=== Convective Heat Loss  ===
=== Convective Heat Loss  ===


[[Image:Leakage_Area_Photos.png|thumb|right|Leakage Areas]]
[[Image:Leakage_Area_Photos.png|thumb|right]]





Revision as of 18:21, 4 December 2010


Abstract

The following page includes information about the creation of Team SAUCee's model 'Can You Feel the Heat Loss?' during Engineering 215: Introduction to Design, Fall 2010. The model will educate visitors of the Samoa Hostel about convection and the effects it has on heat loss in building.

Background

The Samoa Hostel, created by Danco[1] and the Humboldt Bay Center for Sustainable Living, will be located on top of the Samoa Cookhouse. The sustainable and historic hostel that will feature innovative technologies in a common room, shown on the left, in order to educate and inspire its visitors about sustainable living.

Common Room



Convective Heat Loss

Leakage Area Photos.png


Convection is the transfer of heat between a solid and a moving fluid, such as air, due to a difference in temperatures. Therefore, convective heat loss in homes is due to infiltration through cracks and leakage areas. Most leakage areas occur in roofs and ceilings, floors, and walls, yet a significant amount occurs around windows, doors, and outlets, as seen in the figure to the right. In colder environments, buildings are suspectible to a larger amounts of infiltration due to increased differences in indoor/outdoor temperature and wind velocities, known as wind-driven infiltration. Convective heat loss causes many people to spend up to 20% more on heating and cooling bills due to excessive air exchange and resulting energy waste that occurs during the process.

Objective

Team SAUCee's objective was to create a convective heat loss model that will educate people about the effects of convective heat loss and the importance of weatherization.

Criteria

In order of significance, 'Can You Feel the Heat Loss?' needs to be:

  • Educational:describes the model allowing spectators to learn by touching, feeling, and experiencing convective heat loss.
  • Safe: this includes not having anything that could harm or place the audience in danger.
  • Durable: consists of timelessness and the ability to withstand spectators of all ages to interact on a daily basis with the model.
  • Aesthetically pleasing: aesthetics incorporates the theme that binds the insulation models and the convective heat loss models, as well as the sheik and beauty of the model.
  • Cost-effective: encompasses the funds necessary to build and maintain this model, which cannot exceed $500 cumulatively.

Can You Feel the Heat Loss?

Can You Feel the Heat Loss?


Air pump used to mimic infiltration


Our final project consists of a three dimensional model house mounted to a 3x3' back board. The house is split into two almost identical rooms, separated by a 3x1' piece of plywood. Each of these rooms contains a 50W heating bulb located at the top of the room to heat both rooms equally. One room is completely sealed, while the other room contains leakage areas including a moving door and room around windows. The front of the house model is sealed with a 3x2' sheet of plexiglass with two hand slots cut out.

Leaky room
Leakage areas are revealed when the blacklight is turned on
AutoCAD of Top View


These two hand slots are sealed with two rubber sheets screwed into the plexiglas to create a better seal. These two hand slots allow visitors to stick a hand in each side and feel the difference temperature difference. Along with feeling the temperature difference, visitors can see the difference on a indoor/outdoor temperature sensor. Placed on one side of the house model, the sensor reads two different numbers and is labeled for which is the left side and which is the right side. From there, visitors can attempt to guess where the leakage areas are and then turn on a blacklight to visibly see leakage areas painted in blacklight paint. In order to simulate wind, an air pump is provided at the foot of the house model, as shown on the left. This air pump allows visitors to interact with the model by controlling the amount of wind infiltration entering the house model. The house model hooks onto the backboard with two hooks that attach to the "roof", this allows for easy maintenance and the house model to remain secure on the wall. On top of the roof is information on convective heat loss and how to prevent it.


Overall this model best meets our criteria. The collaboration of the following three methods of learning:

[1] feeling the heat,

[2] identifying leakage areas,
and

[3] controlling wind infiltration,

allows for the most interaction and education from the display. The model is safe, with the hand slots located at the bottom of the display to discourage heat bulb- related injuries. The materials used will last long and the cost of maintenance remains relatively low, so the display is sustainable and cost-effective; the model remained below-budget, as dicussed below. After paint, miniature figurines, and Fedex-created information, the model is also aesthetically pleasing.



Cost

Total SAUCee Time: 259 hours


The total design hours spent was at 259 hours total as seen in the pie chart to the right. The most time was spent during the construction and building of the model, followed by time spent performing research necessary to formulate a solution.

The total cost of our design was $128.08, whereas the retail cost was approximately $192.58. The total materials list is seen to the below. We received many donations from Arcata Recycling Center, as well as free wood from around Arcata, allowing us to save approximately $65 in the construction of the model.

Material Qty Our Cost ($) Retail ($)
UV Paint 1 17.45 17.45
60W Blacklight bulb 1 3.49 3.49
Socket Cord 3 8.99 8.99
Silicon Glue 1 3.29 3.29
2x3' Plexiglass 1 6.90 6.90
Rubbersheets 2 4.58 4.58
L-brackets(set of 2) 2 1.50 1.50
Door Hinge 1 0.50 0.50
Plywood 3x3' 1 0.00 5.50
Weatherstripping 1 0.50 0.50
Box of tack nails 1 0.00 8.00
Spraypaint 4 3.49 3.49
Roof Board 1 0.00 7.00
Corner Brace 2 3.99 3.99
Foot Air Pump 1 2.00 10.00
Powerstrip 1 4.31 4.31
50 W Heat Bulb 2 6.49 6.49
Washers 4 0.15 0.15
Oregon Scientific Thermostat 1 12.99 12.99
Total Cost 128.08 192.58



The cost of O&M remained relatively low, with a requirement to change light bulbs and remove collected dust. Thus the cost of O&M yearly would total at $52.47 as seen to the left.

Item Qty Our Cost ($)
50W Heating Bulb 2 6.49 /bulb
60W Blacklight bulb 1 3.49 /bulb
Maintenance (hrs) 3 12.00/hour
Total Cost 52.56



























References

For more in depth look at the project, please read the full design document.

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