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 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/m 2 ˚C Roof 5.17W/m 2 ˚C –Exterior All surfaces 34W/m 2 ˚C

Heat Loss Calculations Used Resistance Network Results Roof Walls Heat Loss Room W Room W Room W Room W Room W Total W

Heat Loss Calculations With Insulation Added Resistance Network Insulation Conductivity k=0.043W/m 2 ˚C Results Roof Walls Heat Loss Room W Room W Room W Room W Room W Total2520.1W =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 ft 3 insulation required –Cellulose insulation cost $0.387 per ft 3 –Total cost to add insulation: $

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, month cost to heat house with insulation –$1, month savings: –$19, Time to recover cost of insulating: –8.4 days

Fresh Air or Oxygen Tank? 4 month analysis of using bottled O 2 – x m 3 /s O 2 consumption rate – 3000L volume of O 2 in tank at 1atm –$1,050 per bottle material –$75 per bottle labor COST – $2,112,750

Fresh Air or Oxygen Tank? 1.6 ft 3 /min addition of outside air to interior – x m 3 /s occupants – x m 3 /s burning gas –-40°C air temperature –$0.045/ft 3 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 = W –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, Labor: –$2, Total –$4, SQUARE DUCTS Material: –$3, Labor: –$2, 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 inchesOutput in Ft^3/min

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 Fluidwater (given)Baffle spacingn/a Tube Fluidwater (given)Baffle cutn/a Mass flow rate shell38.9 kg/sShell ID1.5m Mass flow rate tube22.2 kg/s (given)Shell thickness0.002m Temp. shell in20ºCShell materialstainless Temp. shell outcalculatedTube materialstainless Temp. tube in35ºC (given)Nusselt shellDittus Temp. tube out25ºC (given)Nusselt tubePetukkov-Kirillov Friction factor tube0.0001Tube OD0.0254m Friction factor shell0.0001Tube thickness m Reverse tube/shellnoTube length4.6m Counter flowyesTube pitchcalculated # tube passes1Tube config.square # shell passes1Tube layout90º Baffleno

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 Results

Initial Design Specifications Shell Fluidwater (given)Baffle spacingn/a Tube Fluidwater (given)Baffle cutn/a Mass flow rate shell38.9 kg/sShell ID1.5m Mass flow rate tube22.2 kg/s (given)Shell thickness0.002m Temp. shell in20ºCShell materialstainless Temp. shell outcalculatedTube materialstainless Temp. tube in35ºC (given)Nusselt shellDittus Temp. tube out25ºC (given)Nusselt tubePetukkov-Kirillov Friction factor tube0.0001Tube OD0.0254m Friction factor shell0.0001Tube thickness m Reverse tube/shellnoTube length4.6m Counter flowyesTube pitchcalculated # tube passes1Tube config.square # shell passes1Tube layout90º Baffleno

Final DOE Pareto Charts

Final DOE Optimization 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 Initial1st DOEFinal DOE Heat Transfer (kW) Tube-Side Pressure Loss (Pa) Shell-Side Pressure Loss (Pa)23.714, Weight (kg)22,90232,03526,150

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 Pa –Tube side Pa

Questions?