ME 414 : Project 1 Heating System for NASA North Pole Project Team Members Alan Benedict Jeffrey...
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Transcript of ME 414 : Project 1 Heating System for NASA North Pole Project Team Members Alan Benedict Jeffrey...
ME 414 : Project 1
Heating System for NASA North Pole Project
Team Members
Alan Benedict
Jeffrey Jones
Laura O’Hair
Aaron Randall
May 5, 2006
Problem Statement
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BL
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Your job as a Thermal Fluid Systems engineer is to deliver the housing heating system in the North Pole.
4 occupants
Oxygen supply tank or circulating fresh air from outside
The outside temperature in North Pole is -40C and the desired temperature inside the housing is 25C.
You have a space of 12” in the outside walls and 8” in the interior walls.
Deliverables
• Lowest blower cost measured by the least system pressure drop
• Least material cost measured by the number of sheets used
• Least labor cost per the labor rates given• Least operating cost measured by the
cost of maintenance items and monthly natural gas, oxygen, electricity, etc usage.
• Most comfort to occupants measured by the least flow rate variation between registers
Supply Air System
Return Air System
Heat Loss Calculation Assumptions
• All heat loss occurs through exterior walls and roof.
• The structure is perfectly sealed. No transfer of air.
• There is no heat transfer between rooms.• There is not heat transfer to or from the
basement.
Heat Loss Calculations
• Interior Temperature
25˚C• Exterior
Temperature-40˚C
• Thermal Conductivity of Wall
0.8W/m˚C
• Convection Coefficients– Interior surfaces
• Walls 4.2W/m2˚C• Roof 5.17W/m2˚C
– Exterior• All surfaces
34W/m2˚C
Heat Loss Calculations
Used Resistance Network
Results
Roof
Walls
Heat Loss
Room 1 7791.5WRoom 2 10118.9WRoom 3 6269.2WRoom 4 7380.7WRoom 5 8457.8WTotal 40018.1W
Heat Loss CalculationsWith Insulation Added
Resistance Network
Insulation Conductivity
k=0.043W/m2˚C
Results
Roof
Walls
Heat Loss
Room 1 489.9WRoom 2 634.3WRoom 3 394.4WRoom 4 466.7WRoom 5 534.8WTotal2520.1W
=8598.9Btu/h
Heat Loss Rates
• Heat loss rate through walls and roof:– 2520W
• Heat loss rate through heating of outside air:– 72W
Insulation Cost Benefit Analysis
• Cost to add insulation:– 12 inches in walls and roof– Total of 3501.1 ft3 insulation required– Cellulose insulation cost $0.387 per ft3
– Total cost to add insulation: $1354.07
Insulation Cost Benefit Analysis
• Heat loss rate without insulation:– 40,018.1W
• Heat loss rate with insulation:– 2,520.1W
• Heat loss rate reduction:– 37,498W or 93.7%
Insulation Cost Benefit Analysis
• 4 month cost to heat house without insulation– $20,903.11
• 4 month cost to heat house with insulation– $1,316.35
• 4 month savings:– $19,586.75
• Time to recover cost of insulating:– 8.4 days
Fresh Air or Oxygen Tank?
• 4 month analysis of using bottled O2
– 5.3592 x 10-4 m3/s O2 consumption rate
– 3000L volume of O2 in tank at 1atm
– $1,050 per bottle material– $75 per bottle labor
• COST
–$2,112,750
Fresh Air or Oxygen Tank?
• 1.6 ft3/min addition of outside air to interior– 5.3592 x 10-4 m3/s occupants– 7.7794 x 10-4 m3/s burning gas– -40°C air temperature– $0.045/ft3 cost for natural gas
• COST–$32.28
Furnace and Blower
• Gibson KG6RA Series Specifications– 45000 Btu/h– 80% Efficiency– Cost of $543
Furnace and Blower
Blower Electrical Consumption and Cost for 4 months
• Electricity Consumption– 1/5 hp = 149.14W– 149.14W*2880hrs = 429.5kWhrs
• Operational Cost– 429.5kWhrs*$0.4/kWhr = $171.80
Materials
• Duct Diameter– 7.43 inches– 3 ducts per each 90” X 70” sheet
Materials
• Total sheets– 9
• 90 degree bends– 6
• Branches– 9
• Registers– 9
Material and Labor Costs
CIRCULAR DUCTS• Material:
– $2,250.00
• Labor:– $2,400.00
• Total– $4,650.00
SQUARE DUCTS• Material:
– $3,250.00
• Labor: – $2,600.00
• Total– $5,850.00
Problems not Overcome
• Flowmaster– Flow rates in pump do not coincide with
branch flow rate– Flow rates don’t produce results as
expected
Flow Output of Pump Lower than First Branch
Register size vs. output discrepancy
Diameter in inches Output in Ft^3/min
.30 3.331
.301 3.262
.302 3.192
.303 3.122
.304 3.053
.305 12.93
.306 14.89
.307 17.11
.308 19.74
.309 22.72
.310 14.02
Conclusion
• Least Pressure Drop not achievable through Flowmaster
• Least material cost calculated at $4147
• Least labor cost calculated at $2400• Least operating cost calculated at
$1488• Flow rate variation between registers
not achievable through Flowmaster
Questions?
ME 414 : Project 2
Heat Exchanger Optimization
Team Members
Alan Benedict
Jeffrey Jones
Laura O’Hair
Aaron Randall
May 5, 2006
Problem Statement
Design a heat exchanger to meet the customer requirements for heat transfer and maximum dimensions, while optimizing the weight and pressure losses in both the tube and shell sides.
Project Definition
• Chemical Specifications:– Temperature must be reduced from 35°C to
25°C– Mass flow rate is 80,000 kg/hr– Material properties closely approximate that of
water
• Cooling Water Specifications:– Treated city water at 20°C– Mass flow rate is not fixed– Exit temperature is function of design
Customer Requirements
• Must cool the chemical from 35 C to 25 C• Heat exchanger length can not exceed 7m• Heat exchanger shell diameter can not
exceed 2m• Minimize heat exchanger shell and tube
weight • Minimize heat exchanger pressure drop
Initial Design Specifications
Shell Fluid water (given) Baffle spacing n/a
Tube Fluid water (given) Baffle cut n/a
Mass flow rate shell 38.9 kg/s Shell ID 1.5m
Mass flow rate tube 22.2 kg/s (given) Shell thickness 0.002m
Temp. shell in 20ºC Shell material stainless
Temp. shell out calculated Tube material stainless
Temp. tube in 35ºC (given) Nusselt shell Dittus
Temp. tube out 25ºC (given) Nusselt tube Petukkov-Kirillov
Friction factor tube 0.0001 Tube OD 0.0254m
Friction factor shell 0.0001 Tube thickness 0.00491m
Reverse tube/shell no Tube length 4.6m
Counter flow yes Tube pitch calculated
# tube passes 1 Tube config. square
# shell passes 1 Tube layout 90º
Baffle no
Initial Results
• Desired heat transfer rate of 928,502W
• Calculated heat transfer rate of 924,068W
• Difference of 4,434W• Desired-to-calculated ratio 0.995
First DOE ResultsM
ean o
f Q
Calc
0.029210.02159
1400000
1200000
1000000
1.7251.275 5.293.91
213
1400000
1200000
1000000
213 10
0.40.1
1400000
1200000
1000000
Tube OD Shell ID Tube Length
Tube Mat Shell Mat Baffle
Baffle Space
Main Effects Plot (data means) for Q Calc
Mean o
f W
eig
ht 0.029210.02159
25000
20000
15000
1.7251.275 5.293.91
213
25000
20000
15000
213 10
0.40.1
25000
20000
15000
Tube OD Shell ID Tube Length
Tube Mat Shell Mat Baffle
Baffle Space
Main Effects Plot (data means) for Weight
Mean o
f D
P S
hell 0.029210.02159
300000
150000
0
1.7251.275 5.293.91
213
300000
150000
0
213 10
0.40.1
300000
150000
0
Tube OD Shell ID Tube Length
Tube Mat Shell Mat Baffle
Baffle Space
Main Effects Plot (data means) for DP Shell
Mean o
f D
P T
ube 0.029210.02159
80
60
40
1.7251.275 5.293.91
213
80
60
40
213 10
0.40.1
80
60
40
Tube OD Shell ID Tube Length
Tube Mat Shell Mat Baffle
Baffle Space
Main Effects Plot (data means) for DP Tube
Initial Design Specifications
Shell Fluid water (given) Baffle spacing n/a
Tube Fluid water (given) Baffle cut n/a
Mass flow rate shell 38.9 kg/s Shell ID 1.5m
Mass flow rate tube 22.2 kg/s (given) Shell thickness 0.002m
Temp. shell in 20ºC Shell material stainless
Temp. shell out calculated Tube material stainless
Temp. tube in 35ºC (given) Nusselt shell Dittus
Temp. tube out 25ºC (given) Nusselt tube Petukkov-Kirillov
Friction factor tube 0.0001 Tube OD 0.0254m
Friction factor shell 0.0001 Tube thickness 0.00491m
Reverse tube/shell no Tube length 4.6m
Counter flow yes Tube pitch calculated
# tube passes 1 Tube config. square
# shell passes 1 Tube layout 90º
Baffle no
Final DOE Pareto ChartsTerm
Standardized Effect
AB
AD
BC
CD
B
AC
D
A
C
706050403020100
2.45Factor
Baffle
NameA Tube OD
B Shell IDC Tube LengthD
Pareto Chart of the Standardized Effects(response is Q Calc, Alpha = .05)
Term
Standardized Effect
D
BD
AD
CD
AC
BC
A
B
C
9080706050403020100
2.45Factor
Baffle
NameA Tube OD
B Shell IDC Tube LengthD
Pareto Chart of the Standardized Effects(response is Weight, Alpha = .05)
Term
Standardized Effect
AD
A
C
CD
D
20151050
2.23Factor NameA Tube OD
C Tube LengthD Baffle
Pareto Chart of the Standardized Effects(response is DP Shell, Alpha = .05)
Term
Standardized Effect
BC
AB
AC
B
C
A
35302520151050
2.26Factor NameA Tube OD
B Shell IDC Tube Length
Pareto Chart of the Standardized Effects(response is DP Tube, Alpha = .05)
Final DOE Optimization
Hi
Lo0.00000D
New
Cur
d = 0.99357
Targ: 928502.0Q Calc
d = 0.30544
Minimum
DP Tube
d = 0.99933
MinimumDP Shell
d = 0.00000
Minimum
Weight
y = 9.286E+05
y = 22.3640
y = 16.7174
y = 2.615E+04
0
1
1.50
3.90
1.70
2.0
0.0216
0.0292Shell ID Tube Len BaffleTube OD
[0.0222] [1.8959] [3.0639] 0Hi
Lo0.00000D
New
Cur
d = 0.77655
Targ: 928502.0Q Calc
d = 0.53962
Minimum
DP Tube
d = 0.00000
MinimumDP Shell
d = 0.00000
Minimum
Weight
y = 9.239E+05
y = 16.5096
y = 1.404E+04
y = 2.245E+04
0
1
1.50
3.90
1.70
2.0
0.0216
0.0292Shell ID Tube Len BaffleTube OD
[0.0254] [1.8576] [2.9038] 1
Without Baffles With Baffles
Specifications for Optimized Heat Exchanger
• Counter flow design• Stainless steel material for shell and tube• Single pass shell• Single pass tube• Tube OD of 2.22cm (standard size)• Tube length of 3.06m• Tube thickness of 2.40mm• Tube pitch of 3.18cm• Square tube configuration with 90° layout angle• Shell ID of 1.90m• No baffles
Final Results
Initial 1st DOE Final DOE
Heat Transfer (kW) 924.1 1020.8 929.9
Tube-Side Pressure Loss (Pa) 37.54 8.15 22.36
Shell-Side Pressure Loss (Pa) 23.7 14,500 16.72
Weight (kg) 22,902 32,035 26,150
Conclusion
• Met requirement to cool the chemical from 35 C to 25 C
• Tube length of 3.06m 3.06m<7m• Shell diameter of 1.9m 1.9m<2m• Minimized heat exchanger shell and
tube weight 26,150 kg• Minimized pressure drop
– Shell side 16.72 Pa– Tube side 22.36 Pa
Questions?