Designed a windmill with Systems Approach using XLDyn. This
involved satisfying key stakeholders with requirements and verifying using
constraints and models. The requirements, sub-requirements were classified as
functional and physical. They were mapped and had their parameters defined.
Below mentioned requirements were verified.
- RPM of Generator
- Windspeed
- AverageRainFall
- AverageSnowFall
- Lowest Temperature
- Highest Temperature
- XLconstraint1
- Blade Distance Measurement
- windvelocity
- Stop Time Simulation
- NoiseValue
- Load carrying capacity
- Operator
Assumptions for various requirements
1.Reliability Model:
The windmill runs for 24 hours in 365 days.(Maximum limit scenario)
Whereas actual downtime for the cumulative effect of all the MTBF’s of the sub system components, considering the given parameters of temperature, wind speed, rainfall and snowfall, will be lesser because the number of working days per year would be lesser than 365.
2.Control - Operator Output:
It is assumed that there is a sensor which detects the output power of the generator.When the output power is less than 10 Watts an alarm system starts beeping.This alert system advises the operator to regulate the generator speed in order to bring the power output above 10W.
3.Load Carrying Capacity:
It is assumed from the pugh matrix above that the structure is made up of,
Ground Support - Concrete
Vertical Support - Steel Pole
Rotational Support - Turntable
Hence the load carrying capacity is verified using CAE analysis using loading condition of above 150 kg for this requirement.
4. Wind Velocity:
Wind velocity is measured with a wind speed sensor that shows direction and wind velocity, since it is not a good approach to calculate wind velocity from other parameters.
5. Weather conditions:
Weather conditions like rainfall, snowfall, wind speed and temperature will be observed or measured using CAT/CAE.
6. Noise : Acceptable Decibel level for the Windmill Noise is less than 50 dB
7. Transmission Efficiency : Standard Transmission Efficiency is 90% as per the below graph
Windmill Requirements:
A Generate Energy – Windmill shall be capable of supplying the specified net power under the defined operating conditions
A.1 Output Capability(100<gen_RPM_range<950) – It shall have an output capability to drive a 10 Watt DC continuous load but an operator shall be able to adjust that output to drive any load less than 10 Watts.
B Store Energy – Windmill shall be able to store energy output for future use. Storage mechanism can be application dependent
C QRD – Windmill must be able to withstand environmental and operating loads and meet customer quality and reliability requirements.
C.1 Yearly Average Wind speed(yearlyavgwindspeed=7) – It shall withstand Yearly Average Wind speed of 7mph.
C.2 Yearly Average Rainfall(yearlyavgrainfall=36) – It shall withstand the yearly average rainfall of 2 inch.
C.3 Yearly Average Snowfall(yearlyavgsnowfall=45) – It shall withstand the Yearly Average Snowfall of 45 inch given the Maximum Daily Snowfall of 18 inch.
C.4 Lowest Temp(lowesttemp>-22) – It shall withstand Lowest Temp less than or equal to 22 F.
C.5 Highest Temp(highesttemp<102) – It shall withstand the temperature up to 102 F.
C.6 System Reliability(Downtime<10) – Downtime for the windmill should be less than 10 Days per year.
D Safety – Windmill shall provide safe operation for operators, bystanders, and nearby residents
D.1 Windmill blade distance(minbladedist>4) – Windmill blades shall maintain minimum distance of 4 m from other structures and the ground during operation
D.2 Power down maximum wind velocity(PwDwnMaxWindVel<40) – Windmill shall automatically power down if wind velocity exceeds 40 MPH
D.3 Locking System – It shall provide mechanical lock out to prevent operation of the Windmill during maintenance and extreme environmental conditions.
D.4 Windmill shutdown(stoptime<3) – Windmill shall go from operational velocity to complete stop in 3 sec.
E HMI – Windmill system shall provide for operator monitoring and control of the system
E.1 Monitoring System – It Shall have a monitoring system to record and display rotational speed, power output, wind velocity, and wind direction.
F System Installation Dimensions - Dimensions and weight must be within limits that are compatible with the defined installation environment
F.1 Weight(weight<250) – Total Windmill weight shall not exceed 250 kg
F.2 Height(height<6) – Maximum Windmill height shall be less than 6 m
F.3 Base footprint(base<1.5) – Maximum Windmill footprint shall be less than 1.5 m2..
F.4 Fin Boom(finboom<1.2) – Maximum fin boom length for worst case scenario of Blade length 1 m corresponding to a shaft height of 5 m.
G Blade System – Blade system must convert wind kinetic energy to torque
H Transmission System – Transmission transmits the rotational energy of the blades to the generator. It shall provide optimum speed matching between the blade system and the generator. It shall provide a brake to stop the system.
H.1 Speed Change System – System to match blade rotation to generator speed
H.2 Brake System – Brake system stops all blade rotation
H.3 Noise System – System to control Noise levels for transmission
H.3.1 Noise(dB<50) – The Noise level of the transmission system shall not exceed 50 dB.
H.4 Efficiency System – System to control efficiency of transmission system
H.4.1 Efficiency(eff>90) – Efficiency of Transmission system shall be more that 90%.
I Generator – The generator will provide the required electrical energy
J Structure – The structure holds the blades, transmission, generator and necessary controls in position while undergoing environmental and operating loads. It also provides for rotation of turbine with changing wind direction
J.1 Load carrying capacity(Load<150) – The load carrying capacity of a structure shall not go beyond 150 Kgs.
K Controls – Control System shall maintain safe operation, control distribution of power, monitor status of system, and display system status
K.1 Operator Output(POW<10) Operator shall be able to adjust that output to drive any load less than 10 Watts
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