공조포켓 - 덕트 계산·습공기선도

If you enter an airflow of 4,650 m³/h, circular Ø500 and rectangular 600×350 ducts that deliver air with the same friction will appear immediately. If you enter the diffuser airflow velocity, it will even tell you which damper to tighten.

This is the field calculation notebook for HVAC technicians who select ducts, carry out construction, and perform TAB.

It is stored exclusively on this phone without subscription, advertising, or internet access; a one-time purchase is all you need. With a single backup file, everything remains intact even if you switch phones.

It is an HVAC calculator that instantly calculates duct diameters, pressure loss, humid air state points, and cooling/heating loads per room. It stores duct section tables, air conditions, and diffuser airflow measurements for each site, allowing you to retrieve them as PDFs during design, construction, and TAB. When you enter the airflow, the cross-sections of circular and rectangular ducts delivering air with the same friction are drawn side-by-side at the same scale.

■ Things to Know First

· It does not replace design drawings or TAB reports. This is a tool that performs calculations using publicly available formulas and displays the basis for those calculations.

· The formulas are the publicly available ones from the ASHRAE Handbook Fundamentals — the friction coefficient is calculated by directly solving the Colebrook equation (with Altshul–Tsal comparison values ​​displayed), the Huebscher equivalent diameter is used for rectangular ducts, and the Hyland-Wexler saturation pressure is used for humid air.

· Material roughness, local resistance coefficient, load per area, standard atmospheric pressure, airflow velocity/aspect ratio warnings, and standard circular pipe diameters are all editable default values. The source and reference date are listed for each value, and "Verification Required" is attached to values ​​that have not yet been compared with the original table. You can revert to the default values ​​all at once.

· The local resistance coefficient varies depending on the shape, dimension ratio, and airflow ratio of the same-named accessory. The default values ​​are a starting point; please modify them using the manufacturer's or ASHRAE accessory data. · Actual load is an estimate of the maximum load at a given time under summer/winter design conditions (Wall/Window Heat Transmittance + Window Solar Radiation + People/Lighting/Equipment + Outdoor Air). This is not an hourly heat load calculation or building energy evaluation. Design outdoor conditions, heat transmittance, solar radiation, and occupant heat are editable default values, and "Verification Required" is attached to values ​​that could not be compared with the original text.

· The airflow measurement table is a tool to assist with recording and evaluation. It is not an accredited TAB report.

· Electricity charges are estimates excluding basic charges, progressive rates, and seasonal unit prices.

· Calculations for refrigerants, piping, duct strength, and noise are not performed.

· There is no account, server, or authority. Records are saved only on this phone.

■ Duct — Equal Friction · Air Velocity · Dimensions

· Equal Friction Method: Determine required diameter based on airflow and target friction (Pa/m) → Standard circular diameter, rectangular (fixed aspect ratio or ceiling height) dimensions

· Air Velocity Method: Determine circular or rectangular with the same cross-sectional area based on target air velocity

· Dimensions → Friction: Determine air velocity, friction, and dynamic pressure based on existing duct dimensions

· Select straight pipe length and fittings (elbows, branches, dampers, constrictors, expanders, diffusers, etc.) to calculate the total pressure loss

· Circular ↔ Rectangular Equivalent Diameter, Aspect Ratio, Air Velocity Warning

· Calculation Basis — Re, friction coefficient, friction, and loss are displayed as formulas with actual numbers, allowing comparison with other calculators or manual calculations

· Units: m³/h (CMM/L/s together), Pa/m (mmAq/m together), m/s

· Determining Target Friction — Subtract the static pressure of the coil, filter, and diffuser from the static pressure outside the fan, divide by the main path length (+ equivalent length of fittings) to determine the equal friction target Determining in reverse order

■ Air — Humid Air State Point · Mixing · Condensation

· Absolute humidity, enthalpy, dew point, wet bulb, specific volume, density based on dry-bulb temperature and one of relative humidity, wet-bulb, or dew point

· Editing atmospheric pressure, setting atmospheric pressure by altitude

· Mixing outside air and ventilation — Mixed air condition based on airflow ratio

· Condensation review — Comparing surface temperature and dew point, margin temperature

· We will draw points, dew point, and surface temperature lines on the psychrometric chart

■ Actual Load Calculation · Electricity Bill Estimation (New)

· If you input floor area, exterior wall/window area by orientation, roof, insulation level, glass (single, double, Low-E, triple), sunshade, number of people, lighting/equipment, and outside air volume

· Maximum cooling/heating load (kW · BTU/h · refrigeration ton · kcal/h), sensible heat/latent heat, W/m² per area, required supply airflow

· "Where is heat coming from?" — Wall/roof/window conduction, window solar radiation, people, Displays lighting, equipment, and outside air using color bars and percentages.

· Estimates monthly and annual electricity costs for cooling and heating seasons based on daily operating hours and cooling/heating days.

· Estimates based on Area × W/m²; total heat, sensible heat, latent heat, and dehumidification amounts are also provided based on airflow and coil inlet/outlet air.

■ Airflow Measurement (TAB) Record (New)

· Design airflow and multiple anemometer readings (average × effective area AK) or airflow hood values ​​for each diffuser and grille.

· Bar charts showing % relative to design and within/outside tolerance (default ±10%, adjustable).

· Proportional balance order — based on the lowest fixture, shows how many times the others are relative to the standard and provides "Tighten / Open" guidance.

■ Site — Duct Section Table · Air condition points accumulate.

By inserting duct sections from the fan to the end for each site (building, floor, system), the equal friction automatic dimensions (or existing dimensions), airflow velocity, friction, local losses, and main path static pressure are displayed for each section. Combine. Draw the main duct line as a single line and show the line where the remaining static pressure drops. The measurement and design air state points, actual load, and airflow measurements are also recorded at the same site. For similar floors or systems, start with "Duplicate."

■ PDF · CSV

Preview, save, or send an A4 PDF containing the main duct diagram, section table, accessories, air state points and psychrometric chart, actual load (heat inlet bar, electricity charges), airflow measurement record sheet (design comparison bar, judgment), and the reference values ​​and sources used at that time. You can open the same table as a CSV file in Excel.

■ Font Size

Select the font size in four levels from "More": Normal, Large, Extra Large, and Very Large. The screen is adjusted so that numbers are not cut off even in large font sizes.

■ When You First Open

One example site ("3rd Floor Office Supply Duct (Example)" — 4 sections, main path static pressure 57.7 Pa, 4 air state points, 1 condensation check, 1 room load, 4 diffuser airflow measurements) is included, which you can tap to view immediately. It disappears with a single "Clear Example".

■ Backup and Inquiries

Export site and reference values ​​into a single file and restore them on a new phone. Backup files from other apps are rejected before being overwritten. If records accumulate but 30 days have passed since the last backup, you will be notified once on the main screen. Please send any questions or errors via the "Inquiry" button within the app.

■ For Those

HVAC/Duct Design · Duct Construction · TAB (Test, Adjust, and Balance) · Facility Supervision · Maintenance · Studying for Air Conditioning & Refrigeration Engineer/Industrial Engineer certifications.

No ads. No in-app purchases. One-time purchase.