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Learning Psychrometrics and Sensors measuring T and RH

Learning Psychrometrics and Sensors measuring T and RH. 方煒 台大生機系教授. Wei Fang, Ph.D., Professor Dept. of Bio-Industrial Mechatronics Engineering, National Taiwan University. Analog Dry Bulb Temperature sensor. Analog Dry and Wet Bulb Temperature. Digital Dry Bulb Temperature reader.

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Learning Psychrometrics and Sensors measuring T and RH

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  1. Learning Psychrometrics and Sensors measuring T and RH 方煒 台大生機系教授 Wei Fang, Ph.D., Professor Dept. of Bio-Industrial Mechatronics Engineering, National Taiwan University

  2. Analog Dry Bulb Temperature sensor

  3. Analog Dry and Wet Bulb Temperature

  4. Digital Dry Bulb Temperature reader

  5. Infra-red Dry Bulb Temperature

  6. Sensing element

  7. Dry and wet Bulb Temperature sensors in Weather station and greenhouse

  8. Tdb and RH Sensors

  9. Tdb and RH data logger

  10. Day/Night trends of T and RH

  11. 濕度 溫度 午夜 中午 午夜 High T coexist with Low Hum.

  12. High humid Env. Low T, High RH High T, Low RH

  13. Forced ventilation

  14. Evaporative cooling Fogging

  15. Evaporative cooling Pad and Fan system

  16. Approach to release thermal stress

  17. Approach to release thermal stress Beware of the side effect.

  18. Psychrometric Chart

  19. Process: from one state to another

  20. Human comfort zone

  21. Animal comfort zone – T only Productivity Dry bulb temperature

  22. Impact of T and RH on milk production of cows 82.49 64.65 72.32 63.39 68.47 76.68 64.31 65.05 75.73 79.96 63.7 87.09 90.09 88.06 86.01 82.09 84.21 82.36 THI>85, no recovery Adapted from ASHRAE Fundamentals, 1999

  23. Reduction of milk vs. Temperature-Humidity Index (THI) Adapted from ASHRAE Fundamentals, 1999

  24. Milk Production=f(HD74, HA80S) MP =21.48 – 0.051 * HD74 – 0.0099 * HA80S Where, • MP: Milk production (in kg/day/cow) • 21.48: daily production (in kg) per cow in normal weather condition • HD74: total hrs of THI > 74 for previous 4 days • HA80S: square of total hrs of THI > 80 for previous day Linvill and Pardue (1992)

  25. THI lines on Psychrometric chart

  26. More about Psychrometric chart Following contents, created by the author, are available from DSpace at UVM. • Tutorial for digital psy chart • Digital psychrometric chart software

  27. The End

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