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Fluids, pumps, psychrometrics & plant rooms

Fluid Mechanics, HVAC & Refrigeration

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Fluid Statics & Flow Fundamentals

  • L1
    Reading the fluid
    density, specific gravity, pressure, head, flow
    ★★★★★
    Start
  • L2
    Pressure under depth
    P = ρgh · and the metre-to-kilopascal bridge
    ★★★★★
    Start
  • L3
    Continuity
    Q = Av · and the diameter that has to be squared
    ★★★★★
    Start
  • L4
    The two heads
    the same motion, priced in kilopascals and in metres
    ★★★★★
    Start
  • L5
    Bernoulli between two points
    pressure, motion and height, trading along a streamline
    ★★★★★
    Start
  • L6
    Reynolds and the regime
    2300 · the number that decides which physics applies
    ★★★★★
    Start
  • L7
    Buoyancy
    the fluid pushed aside, and who actually pays
    ★★★★★
    Start
  • ★
    The Standpipe
    the boss · no calculator · depth to pressure to jet to duty
    ★★★★★
    Start

Pipe Flow & Head Loss

  • L9
    Darcy–Weisbach
    the L/D lever, and the v² punishment
    ★★★★★
    Start
  • L10
    Finding f
    the regime decides the relation — and 2300 is the border
    ★★★★★
    Start
  • L11
    Hazen–Williams
    the C factor, and what an old main confesses
    ★★★★★
    Start
  • L12
    Minor losses
    two sets of books for the same elbow
    ★★★★★
    Start
  • L13
    Valve coefficients
    Kv and Cv — a valve priced by what it passes
    ★★★★★
    Start
  • L14
    Metering the flow
    squeeze the stream, then read the squeeze
    ★★★★★
    Start
  • L15
    Pipe wall and surge
    what the wall holds, and what a slammed valve throws at it
    ★★★★★
    Start
  • L16
    What the pipe holds
    system volume — the cylinder, and the awkward one
    ★★★★★
    Start
  • ★
    The Longest Run
    the boss · no calculator · one line sized end to end
    ★★★★★
    Start

Pumps, Fans & Affinity Laws

  • L18
    Total dynamic head
    everything converts to metres before anything is added
    ★★★★★
    Start
  • L19
    Water power
    P = ρgQH · the kilowatts that actually reach the liquid
    ★★★★★
    Start
  • L20
    Shaft power and efficiency
    efficiency divides on the way out to the coupling
    ★★★★★
    Start
  • L21
    NPSH available
    the suction-side margin above boiling — and what eats it
    ★★★★★
    Start
  • L22
    Affinity with speed
    linear, squared, CUBED — one lever, three exponents
    ★★★★★
    Start
  • L23
    Affinity with impeller trim
    same ladder, different lever — and the metal does not grow back
    ★★★★★
    Start
  • L24
    Fan laws
    the same three exponents, in pascals and cubic metres per second
    ★★★★★
    Start
  • L25
    Specific speed
    one number that names the shape of the impeller
    ★★★★★
    Start
  • ★
    The Pump Room
    the boss · no calculator · head to kilowatts to a new speed
    ★★★★★
    Start

Psychrometrics

  • L27
    Reading moist air
    three thermometers, a percentage, and four pressures
    ★★★★★
    Start
  • L28
    The saturation curve
    how much water air can hold — an exponential, not a line
    ★★★★★
    Start
  • L29
    Humidity ratio and RH
    the 0.62198, the dry-air denominator, and why W does not move
    ★★★★★
    Start
  • L30
    Dew point
    the temperature a surface starts to sweat at, two ways
    ★★★★★
    Start
  • L31
    Wet bulb
    the sling psychrometer, and the temperature evaporation can reach
    ★★★★★
    Start
  • L32
    Enthalpy and specific volume
    per kilogram of DRY air — and what altitude does to the trade rules
    ★★★★★
    Start
  • L33
    Mixing airstreams
    mass-weighted averages, and the ratio that is not RH
    ★★★★★
    Start
  • ★
    The Air Handler
    the boss · no calculator · outdoor meets return, and the coil pays for it
    ★★★★★
    Start

Air Systems & Hydronics

  • L35
    The three air rules
    sensible, latent, total — one airstream, three questions
    ★★★★★
    Start
  • L36
    Sensible heat ratio
    sensible over TOTAL — the number that decides cool from clammy
    ★★★★★
    Start
  • L37
    Duct velocity
    flow over area — and the rectangle that pretends to be round
    ★★★★★
    Start
  • L38
    Air changes per hour
    roomfuls an hour · and the two sixties between them
    ★★★★★
    Start
  • L39
    The 500 rule
    4.18 kW per litre per second per kelvin — and what glycol takes back
    ★★★★★
    Start
  • L40
    Loop hardware
    the water grows, the tank swallows it, the fill valve lifts it
    ★★★★★
    Start
  • L41
    Emitters off design
    the 1.3 exponent · why low-temperature heat shrinks a radiator
    ★★★★★
    Start
  • L42
    Seasonal energy
    degree-days to kilowatt-hours to dollars
    ★★★★★
    Start
  • ★
    The Balancing Report
    the boss · no calculator · duct traverse to boiler input, and a verdict
    ★★★★★
    Start

Refrigeration, Boilers & Cooling Towers

  • L44
    Tons, EER and COP
    three dialects, one machine — and 3.517 is not 3.412
    ★★★★★
    Start
  • L45
    kW per ton
    the one figure of merit where lower is better
    ★★★★★
    Start
  • L46
    COP from enthalpies
    refrigerating effect over compressor work, straight off the chart
    ★★★★★
    Start
  • L47
    Superheat and subcooling
    two thermometers, two pressures, two verdicts
    ★★★★★
    Start
  • L48
    Refrigerant mass flow
    ṁ = Q̇ / Δh, asked every way round
    ★★★★★
    Start
  • L49
    Condenser duty
    the tower carries the load PLUS the compressor
    ★★★★★
    Start
  • L50
    Tower temperatures
    range is the plant's doing; approach is the tower's
    ★★★★★
    Start
  • L51
    Tower water balance
    evaporation, cycles, blowdown, makeup — in that order
    ★★★★★
    Start
  • L52
    Boiler horsepower
    9.81 kW apiece — and it is not a horsepower
    ★★★★★
    Start
  • ★
    The Plant Room Final
    the boss · no calculator · chiller nameplate to tower bleed
    ★★★★★
    Start

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