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Some Basic HVAC

Some Basic HVAC. HVAC - Cooling. First Law of Thermodynamics. Enthalpy . H = U + PV. Second Law: Entropy . dS = dQ/T. HVAC - Cooling. Second Law: Entropy . HVAC - Cooling. ideal. COP – dimensionless! – EER – dimensions of Btu/h/W!. kpH’. evQ. HVAC - Cooling. kpH’. evQ.

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Some Basic HVAC

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  1. Some Basic HVAC

  2. HVAC - Cooling First Law of Thermodynamics Enthalpy H = U + PV Second Law:Entropy dS = dQ/T

  3. HVAC - Cooling Second Law:Entropy

  4. HVAC - Cooling ideal COP – dimensionless! – EER – dimensions of Btu/h/W! kpH’ evQ

  5. HVAC - Cooling kpH’ evQ COP = evQ / kpH’ = (h1-h4) / (h2-h1)

  6. HVAC - Cooling COP = evQ / kpH’ = (h1-h4) / (h2-h1) Nipuna

  7. HVAC - Cooling Stay away from Window Air Conditioner

  8. HVAC - Cooling Split System

  9. HVAC - Cooling Cooling Tower Chilled-water System

  10. HVAC - Cooling Reciprocating Compressor Scroll Compressor Chilled-water System

  11. HVAC - Cooling Chilled-water System Chilled-water System:Centrifugal Compressor

  12. HVAC - Cooling Rooftop Units

  13. HVAC - Cooling Rooftop Units

  14. HVAC - Cooling Rooftop Units

  15. HVAC - Cooling Saturation humidity line: Relative humidity line Wet bulb temperature lines Specific volume lines Enthalpy lines Psychrometric Chart

  16. HVAC - Cooling

  17. HVAC - Cooling The energy efficiency rating (EER) of an air conditioner is its BTU/h rating over its Wattage. Example: window air conditioner Rating: 10,000-BTU/h Power Consumption: 1,200 watts EER = 10,000 BTU/h/1,200 watts = 8.3 Btu/Wh Normally a higher EER is accompanied by a higher price.

  18. HVAC - Cooling • Choice between two 10,000-BTU/h units • 1. EER of 8.3, consumes 1,200 watts • EER of 10, consumes 1000 watts. • Price difference is $100. • Usage: 4 months a year, 6 hours a day. • Electricity Cost: $0.10/kWh. • =========================================== • 4 mo. x 30 days/mo. x 6 hr/day = 720 hours • (720 h x .2 kW) x $0.10/kWh = $14.40 Savings • Since the EER 10 unit costs $100 more, • it will take about seven years for this more expensive unit • to break even

  19. HVAC - Cooling

  20. HVAC - Cooling

  21. HVAC -Heating High Efficiency Upflow Furnace Efficiency: .8 - .95

  22. HVAC -Heating FIRETUBE BOILER

  23. HVAC -Heating Disadvantages of Firetube Boilers include: Not suitable for high pressure applications 250 psig and above Limitation for high capacity steam generation Disadvantages of the Watertube design include: High initial capital cost Cleaning is more difficult due to the design No commonality between tubes Physical size may be an issue FIRETUBE BOILERS WATERTUBE BOILERS

  24. HVAC -Heating Scotch Boiler

  25. HVAC -Heating

  26. HVAC -Heating

  27. HVAC -Heating Thermostatic Steam Traps Mechanical Steam Traps 

  28. HVAC -Heating Thermodynamic Steam Traps Orifice Steam Traps 

  29. HVAC -Heating Determination of Efficiency 

  30. HVAC -Heating

  31. HVAC -Heating

  32. HVAC Motors Radial Flow belt driven Fan

  33. HVAC Fans Radial Flow belt driven Fan

  34. HVAC Motors velocity p static dp Total p B = C + A

  35. HVAC Motors

  36. HVAC Motors Variable Frequency Drive is closest to Centrifugal Fan Law

  37. HVAC Motors Variable Speed Drive

  38. HVAC –Ventilation Distribution System and Controls

  39. HVAC –Ventilation Circulation Systems

  40. HVAC –Ventilation Circulation Systems Two Duct System

  41. HVAC –Ventilation Circulation Systems Four Pipe Systems

  42. HVAC - Envelope Building Envelope

  43. HVAC - Envelope Building EnvelopeNipuna en:p:ÙN:

  44. HVAC - Envelope Building EnvelopeNipuna en:p:ÙN:

  45. HVAC - Envelope Building Envelope – HDD/CDD Data

  46. HVAC - Envelope Building Envelope Values from G. Pita “Air Conditioning and Principles”, 2002

  47. HVAC - Envelope Building Envelope NY Data

  48. HVAC - Envelope Building Envelope NY Data

  49. HVAC - Envelope Windows

  50. HVAC - Envelope Windows

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