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

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Presentation on theme: "Some Basic HVAC. First Law of Thermodynamics H = U + PV Enthalpy Second Law: Entropy HVAC - Cooling dS = dQ/T."— Presentation transcript:

1 Some Basic HVAC

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

3 Second Law: Entropy HVAC - Cooling

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

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

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

7 Stay away from Window Air Conditioner HVAC - Cooling

8 Split System HVAC - Cooling

9 Chilled-water System Cooling Tower HVAC - Cooling

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

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

12 Rooftop Units HVAC - Cooling

13 Rooftop Units HVAC - Cooling

14 Rooftop Units HVAC - Cooling

15 Saturation humidity line:Wet bulb temperature linesRelative humidity line Specific volume linesEnthalpy lines Psychrometric Chart HVAC - Cooling

16

17 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. HVAC - Cooling

18 Choice between two 10,000-BTU/h units 1. EER of 8.3, consumes 1,200 watts 2. 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 HVAC - Cooling

19

20

21 HVAC -Heating High Efficiency Upflow Furnace Efficiency:

22 FIRETUBE BOILER HVAC -Heating

23 FIRETUBE BOILERS WATERTUBE BOILERS 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 Disadvantages of Firetube Boilers include: Not suitable for high pressure applications 250 psig and above Limitation for high capacity steam generation HVAC -Heating

24 Scotch Boiler HVAC -Heating

25

26

27 Thermostatic Steam Traps Mechanical Steam Traps HVAC -Heating

28 Thermodynamic Steam Traps Orifice Steam Traps HVAC -Heating

29 Determination of Efficiency HVAC -Heating

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31

32 HVAC Motors Radial Flow belt driven Fan

33 HVAC Fans

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

35

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

37 Variable Speed Drive HVAC Motors

38 HVAC –Ventilation Distribution System and Controls

39 Circulation Systems HVAC –Ventilation

40 Circulation Systems Two Duct System HVAC –Ventilation

41 Four Pipe Systems Circulation Systems HVAC –Ventilation

42 HVAC - Envelope Building Envelope

43 Building Envelope Nipuna en:p:ÙN: HVAC - Envelope

44 Building Envelope Nipuna en:p:ÙN: HVAC - Envelope

45 Building Envelope – HDD/CDD Data HVAC - Envelope

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

47 Building Envelope NY Data HVAC - Envelope

48 Building Envelope NY Data HVAC - Envelope

49 Windows HVAC - Envelope

50 Windows HVAC - Envelope

51 eQuest and Power DOE Modeling


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