Weekly Heat Transfer Projects

Projects are due at the beginning of the Wednesday class period each week.

Problem numbers in parenthesis (1.10) are from old text book by Chengel "Heat Transfer".

 

Week
Date due
Topic

Project Hand-in Assignment

(due on Wednesday at beginning of class)

1
Mar 21 Basic concepts of of thermodynamics and heat transfer.

Review Problem 1-117, WIND CHILL FACTOR- Solve the stated problem using EES. Do research to find out how the weather man calculates the "wind chill factor" that is reported with winter time weather reports on radio and TV. What is the formula they use? What are the mechanisms of heat transfer ? Refer to NOAA Wind Chill Factor Chart

2
Mar 28 Steady state conduction-economic value of insulation Do text problem 3.31(3-31). Use a parametric study to determine the thickness of fiberglass that will reduce the heat transfer by 90 percent (plot a graph). Determine the simple payback in years by dividing the project cost by the annual savings.
3 Apr 4

Steady state conduction through fins.

 

Do text problems 3-181, 3-182. In this problem you are asked to examine the effects of fin spacing on heat transfer. Use EES to solve the problem and do the parametric study indicated in 3-182. To do a parametric study you will need to make a parametric table. Note that to solve the table you need to use the solve menu selecting "solve table" or use the solve table icon on the tool bar.You can copy the figure on the left into the diagram window of EES. Hint: use eq. 3-71 to calculate the fin efficiency. Note that the hyperbolic tangent is a function in EES.
4
April 11 Radiant floor heating. Do design and essay problem number 3-240. Some added information is that the winter design outdoor temperature in Rochester, NY is +5F. Be sure to document your calculations and assumptions. Determine the overall heat transfer coefficient for the house. Use the shape factor method to determine the heat transfer from the floor. Instead of burying the pipes in the ground, imbed the pipes into a concrete floor slab that is 4.0 inches thick and is poured over a layer of insulation to prevent heat loss into the ground.
5
April 18 Transient conduction

Refer to text problems 4-25 and 4-26. Use EES to determine the following:

  • Plot temperature vs. time for annealing temperatures from 500C to 1000C (plot all on one plot for comparison purposes.
  • Plot instantaneous heat transfer rate vs time for the various annealing temperatures.
  • Tabulate the total energy given off per hour in each of the cooling processes modeled.
6 April25 Forced convection

FORCED CONVECTION

Do text problem 7.104 using EES to solve. EES is almost necessary because it is a trial-and-error solution if you do it by hand. Make certain that you enter the temperatures in absolute degrees. In addition to answering the posed question, vary the wind from 5 to 100 kmh to examine the effect of wind (forced convection) on the heat loss. Remember to include the effect of radiation exchange between the roof and the sky in parallel with the convection exchange between the roof and the air (wind). Do not be surprised if there is a heat flow from the air into the roof surface for some or all of the wind speeds.

7

May 2 Natural Convection Essay problem 9.135 (9-114) Cooling of plates in an industrial process. Use the EES diagram window to create an input/output graphic interface to input the specified plate dimensions and properties for the user. Include a "solve" button on the diagram window as well. Refer to the "diagram window" examples in the "examples" menu in EES to learn more about how to use the diagram window for input and output values as well as selecting the material of the plate. the "examples" menu . Also use the EES example for Integration "diffeq1.ees" to see a very similar problem solution (but without the radiation component of heat transfer). You must add the radiation component to your solution.
8
May 9 Heat Exchanger

Do text problem 11.54(13.49). The solution to the related problem 11.53(13.48).

"A thin-walled double-pipe counter-flow heat exchanger (ref Fig 11.1) is to be used to cool oil (cp = 2200 J/kg - C) from 150 C to 40 C at a rate of 2 kg/s by water (cp = 4180 J/kg -C) that enters at 22 C at a rate of 1.5 kg/s. The diameter of the tube is 2.5 cm, and its length is 6 m. Determine the overall heattransfer coefficient of this heat exchanger.Investigate the effects of oil exit temperature and water inlet temperature on the overall heat transfer coefficient of the heat exchanger. Let the oil exit temperature vary from 30 C to 70 C and the water inlet temperature from 5 C to 25 C. Plot the overall heat transfer coefficient as functions of the two temperatures, and discuss the results."

 

9
May 16 Heat Exchangers Present the solution to the steam condenser problems 11.109/110(13.100/101) in a report format with a full textural explanation of the problem, the solution and your conclusions. Note change water flow to 180,000 kg/hr. Use the NTU or LMTD method for this. Prepare the report in WORD. Place your supporting calculations (performed in EES) in an appendix to your report. Refer to example report for page layout, figure and table examples.
  Radiation Heat Transfer Do text problem 12.40 (EES) Plot radiation heat transfer on the -axis and side length on the x-axis, plot lines of constant emissivity on this graph by using the "overlay plot" feature. Note that all the radiation leaving the sphere impinges on the enclosure so that the view factor from it to the enclosure is 1.0. Use the reciprocity equation to determine the view factor from the enclosure to the sphere.

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