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Fruit and vegetable drying

Moisture balance, air flow, heater power, energy, tray area and drying time for fruit, vegetables, mushrooms and pasta products.

What the calculator computes

The calculator estimates convective drying of fruit, vegetables, mushrooms and pasta semi-finished products in a chamber (tray) or continuous dryer: how much water must be evaporated, how much air and heat are needed for this, what tray area is required and — for products with verified data — how long the drying takes.

What you need to enter

  • a product from the reference book (the moisture is filled in and can be changed) or your own values;
  • batch mass or capacity by raw material per hour;
  • initial and final moisture and the fraction of inclusions — stones and stalks that go to waste before drying;
  • temperature and relative humidity of the ambient air, temperature and velocity of the air in the dryer;
  • raw material load per 1 m² of tray and atmospheric pressure.

What you will get

  • Moisture balance: dry matter, mass of the dried product, evaporated water and yield of the finished product.
  • Air and energy: air state at the inlet, after the heater and at the outlet, air flow rate, heater power, energy per 1 kg of evaporated water, required flow cross-section.
  • Trays and batches: required tray area and number of batches per day.
  • Drying duration and curve — for products whose tabulated data has been verified by a technologist.
  • Charts: psychrometric chart with the process line, moisture reduction curve over time and a diagram of air movement through the product layers.

How it is calculated

The moisture balance, air state and energy are calculated from well-known relationships of technical thermodynamics and psychrometrics, directly in your browser. The drying duration and curve are based on practical drying regimes for specific products verified by a technologist, and are recalculated by the server for your temperature and load. Values that depend on assumptions (how far the air is saturated with moisture at the outlet, heat losses, product regime) are shown as a “from — to” range; balance values as a single number marked “calculation”.

If, under the given conditions, the air after heating is already saturated with moisture, the calculator will warn that drying is impossible. The result is approximate: the fan and heater are selected with a margin, because at the start of drying the product gives up water faster than the average over the cycle.

Calculation example

Batch of 1000 kg, moisture 88 % → 12 %, air at 20 °C and 50 % heated to 60 °C

Input data

Raw material mass
1,000 kg
Raw material moisture
88 %
Finished product moisture
12 %
Ambient air
20 °C
Relative humidity
50 %
Dryer temperature
60 °C
Tray load
15 kg/m²

Result

Dry matter calculation
120 kg
Dried product calculation
136.4 kg
Evaporated water calculation
863.6 kg
Finished product yield calculation
13.6 %
Tray area calculation
66.7 m²
Inlet air humidity ratio calculation
7.2 g/kg
Air per 1 kg of water range
86 – 122 kg
Air per batch range
74,100 – 105,000 kg
Heat per batch range
924 – 1,490 kWh
Specific energy range
1.07 – 1.72 kWh/kg of water

Approach to saturation of the outlet air 60–85 %, heat losses 10–25 %. Drying time and curve are shown only for products whose data have been verified by a technologist.

The calculations are approximate: they help to assess the process and compare options, but do not replace a process design and trials on a specific raw material. This section is for reference only and contains no commercial offers.