Balancing of a Water and Air System (PDF

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56 The Doppler meter is not suited for HVAC system hydronic measurement because it requires systems handling particulate matter to be accurate. Hydronic Flow Measuring Orifice Plate A calibrated orifice plate is a plate permanently installed in the pipe that as been calibrated by measuring the pressure drop against a known flow. The accuracy is dependent on the pipe location and the instrument used to measure pressure differential (Figure 11.1). The orifice shall be located according to the manufacturer's recommendations. 56
57 Venturi The venturi is a device permanently installed in the pipe that has been calibrated by measuring the pressure drop against a known flow. Venturis must be located according to the manufacturer's recommendations to maintain accuracy of 2% (Figure 11.2). Hydronic Pitot Tube Traverse The Pitot rod is a pair of tubes in a casing. One tube measures a static head pressure, and the other tube which faces in the direction of flow, measures the total head pressure. The Pitot rod is a manually inserted device used to take a series of velocity measurements, which are averaged and used to determine flow. (Figures 11.3 and 11.4). A manometer is attached to measure flow. GPM = FPM X Gallons per foot FPM = 1040 X √ VP Example 7A Find the Gpm of a system that has a Cfm of 10,000 with a entering air of 80°F Dry bulb, 67°F wet bulb and a leaving air of 62°F dry bulb , 57.5°F wet bulb. The water entering is 45°F and leaving is 55°F. 80°F dry with a 67°F wet is a 31.51 enthalpy and 62°F dry 57.5°F wet is a enthalpy of 24.77 with a air density of 0.0757 Solution Gpm = Air Density X CFM X ∆ Enthalpy / 8.337 X ∆ temperature of the water 0.0757 X 10,000 X 6.74 / 8.337 X 10 = 5102.18 / 83.37 = 61.2 GPM 57
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Balancing of a water and air system
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3 8 TBA (Testing, Balancing and Adj
Page 5 and 6: 5 Air Balancing Multiple Hood syste
Page 7 and 8: 7 87 Series Loop 88 One pipe main 9
Page 9 and 10: 9 Testing and Balancing HVAC A syst
Page 11 and 12: 11 13. Filter frame properly instal
Page 13 and 14: 13 13. Measure and record all requi
Page 15 and 16: 15 15 Example 3: Find the nearest s
Page 17 and 18: 17 For traverses taken in round duc
Page 19 and 20: 19 Flat Oval Duct Traverses For fie
Page 21 and 22: 21 Balancing Devices Volume Dampers
Page 23 and 24: 23 Turning Vanes Turning vanes (Fig
Page 25 and 26: 25 Balancing the VAV System The gen
Page 27 and 28: 27 maximum out-side air damper for
Page 29 and 30: 29 determines how much energy is in
Page 31 and 32: 31 the water removing capacity of a
Page 33 and 34: 33 Table 8A Dry Bulb on left, Wet B
Page 35 and 36: 35 60 58 56 54 52 50 48 46 44 42 40
Page 37 and 38: 37 Foot³ per 1lb Altitude 0 Feet A
Page 39 and 40: 39 Table 9 C Air Density at 29.29
Page 41 and 42: 41 41 Wet-Bulb (F) .0 .1 .2 .3 .4 .
Page 43 and 44: 43 Table 11A Enthalpy at saturation
Page 45 and 46: 45 Table 11 C Enthalpy at saturatio
Page 47 and 48: 47 Wet bulb temperature____________
Page 49 and 50: 49 and replacement should be shut o
Page 51 and 52: 51 duct may be great; the balancing
Page 53 and 54: 53 Design below the 250°F limit (A
Page 55: 55 Differential Pressure Gauges The
Page 59 and 60: 59 Pressure Total pressure Velocity
Page 61 and 62: 61 Table 1 shows that if the coil i
Page 63 and 64: 63 adjustment of these devices is n
Page 65 and 66: 65 Grouting Motor and lubrication N
Page 67 and 68: 67 For every outside temperature ot
Page 69 and 70: 69 4. Identify the riser with the h
Page 71 and 72: 71 2. Turn the pump off 3. Close th
Page 73 and 74: 73 Net positive suction head availa
Page 75 and 76: 75 All automatic control valves mus
Page 77 and 78: 77 77
Page 79 and 80: 79 4. Read and record the actual pu
Page 81 and 82: 81 13. Record the coils design and
Page 83 and 84: 83 Air Control Air is always presen
Page 85 and 86: 85 • allow draining of all or par
Page 87 and 88: 87 Valves have linear throttling ch
Page 89 and 90: 89 to all the terminals down the li
Page 91 and 92: 91 Pump Circuits Primary-Secondary
Page 93 and 94: 93 • Evaporator: • the design a
Page 95 and 96: 95 95
Page 97 and 98: 97 Condenser • the design and act
Page 99 and 100: 99 • Each reading of liquid tempe
Page 101 and 102: 101 • Design and actual entering
Page 103 and 104: 103 differs from the average by mor
Page 105 and 106: 105 • Orifice plate • Turbine m
Page 107 and 108:
107 BTUH = GPM X 60 X 8.337 X ∆T
Page 109 and 110:
109 Lam = lbs. of air per minute th
Page 111 and 112:
111 When dry bulb temperature measu
Page 113 and 114:
113 GPM = FPM X Gallons per foot FP
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