PiDryer-Tray is a real-time simulator of a convective tray dryer. Ambient air is drawn by a centrifugal fan, heated by an electric resistance heater, and directed across a tray of wet granular material; as moisture evaporates from the surface, a digital balance continuously reports the wet-sand mass, tracing the complete drying curve from the constant-rate period through the falling-rate period as it happens. Built by PiControl Solutions, PiDryer-Tray lets a user control the fan, heater, and initial loading and watch the inlet and outlet temperatures, humidity ratios, air velocity, and drying curve respond at once.
All psychrometric values in PiDryer-Tray use the ASHRAE energy-balance wet-bulb method, which correctly handles the large dry-to-wet-bulb depressions that occur when heated air at 50 to 60 degrees C meets a wet surface near 25 degrees C, conditions where simpler empirical formulas lose accuracy by several degrees. That accuracy matters because the drying curve, and the transition from constant-rate to falling-rate drying, only makes sense once the underlying psychrometrics are trustworthy at those elevated temperatures.
The problem: Convective drying is one of the most common unit operations in chemical and food processing, and most students first meet it through a printed drying-curve diagram: constant-rate period, critical moisture content, falling-rate period, three concepts on one graph. That diagram never shows how the curve actually develops as fan speed and heater setting change, or how a real heater's power output is nonlinear with its dial setting. A training gap here touches nearly every drying operation a plant runs.
A printed drying-curve diagram shows one idealized shape. It never shows how the curve actually develops for a specific fan speed, heater setting, and initial loading. Students who can label the diagram are often unprepared for how a real dryer behaves.
Most students assume a heater's power output is proportional to its dial setting. A square-root relationship, where a mid setting delivers roughly 70% of maximum power, is easy to state and hard to internalize without watching it play out live.
Simple empirical wet-bulb formulas lose several degrees of accuracy at the large dry-to-wet-bulb depressions that heated dryer air creates. Engineers who have only used simple formulas can be caught off guard by that error.
PiDryer-Tray removes the structural problem: a live drying curve that develops in real time, an ASHRAE energy-balance wet-bulb method accurate at elevated temperatures, and heater-nonlinearity and fan-heater coupling models that behave like the actual equipment, not the idealized textbook diagram. Engineers and students who train on PiDryer-Tray build intuition that a printed diagram cannot provide.
PiDryer-Tray is built to be operated, logged, and analysed like real pilot-scale equipment.
Updates every simulation second, so all instruments respond dynamically to fan-speed and heater changes.
Reflects actual dryer timing, so learners see how convective drying behaves under realistic dynamics, not textbook idealization.
Plots balance readings against time, showing the constant-rate to falling-rate transition and the steady-state evaporation slope.
Turns an abstract textbook curve into a live reading students watch develop in front of them.
Real-time trend charts for all four temperatures and the wet-sand mass, with zoom for inspecting drying transients.
Lets students inspect transients as fan speed and heater setting change, not just steady-state values.
Every variable logged with a timestamped header, for moisture-content and mass-balance calculations in Excel, MATLAB, or Python.
Lets students verify their own drying-curve and mass-balance calculations against the simulator's live data.
Heater maximum power and efficiency, the power-law exponent, the drying-rate coefficient, and the fan time constant in a plain-text file.
Lets an instructor recalibrate the model to match their own equipment without touching source code.
Installs and runs entirely on a Windows PC, no cloud dependency, no DCS hardware.
Fits online teaching and virtual laboratories, wherever the student or engineer is located.
Energy-balance wet-bulb method, accurate at the elevated inlet temperatures where empirical formulas lose accuracy.
Keeps the drying curve grounded in trustworthy psychrometrics at the elevated temperatures a dryer actually runs at.
Thermal power follows a square-root relationship with the dial setting, matching phase-angle-controlled heaters.
Teaches students that control response is not always proportional to the setting, before they meet that surprise on real equipment.
Process engineers and technicians use PiDryer-Tray to explore dryer operating conditions, heater-power requirements, and air-flow trade-offs before making changes on process equipment. Practicing on PiDryer-Tray lets engineers validate mass and energy balances against instrument readings, without production risk on a real industrial process control system.
Engineering colleges and universities use PiDryer-Tray in courses and lab sessions covering heat and mass transfer, drying operations, and psychrometrics, particularly within chemical engineering. PiDryer-Tray replaces a static drying-curve diagram with hands-on simulator practice, letting students watch the constant-rate and falling-rate periods unfold live, with no physical laboratory equipment required.
PiDryer-Tray is part of PiControl's family of real-time process simulators, each built around a different loop or unit operation.
PiCoolTower simulates a wet cooling tower using the same ASHRAE psychrometric approach, a natural companion for a heat and mass transfer curriculum.
PiEvap simulates a double-effect evaporator, another mass-transfer unit operation students meet alongside convective drying.
PiHEx simulates a shell-and-tube heat exchanger network, another heat-transfer unit operation in the same real-time simulator family.
Convective drying is a common unit operation across chemical, food, and pharmaceutical processing.
The ASHRAE wet-bulb method, heater-nonlinearity modeling, and offline classroom use.
See PiDryer-Tray run in real time and watch the drying curve play out live from the constant-rate through the falling-rate period. A PiControl engineer will demonstrate the simulator on scenarios relevant to your plant or curriculum, and discuss licensing options for your team.
