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Thermexcel Programme — Psychrosi

  • Thermexcel is a known software tool developed by the French company CETIAT (Centre Technique des Industries Aérauliques et Thermiques). It is a thermal calculation software used for heat exchanger design, particularly for finned-tube heat exchangers (air coolers, condensers, evaporators) in HVAC&R (Heating, Ventilation, Air Conditioning, and Refrigeration).
  • Psychrosi does not correspond to a standard English or French technical term. However, it resembles psychrometry (the study of moist air properties) — in French, psychrométrie. It might be a misspelling of psychrométrie or possibly a brand name / internal code.

Given this, the most plausible interpretation is that you are asking for a report on Thermexcel software applied to psychrometric processes, especially cooling, dehumidification, or frosting/defrosting conditions (where “psychrosi” could be a coined term from Greek psychros = cold).

Below is a detailed technical report based on that interpretation.

C. Coil Exit Fogging Predictor (Psychrosi Safety)

  • Problem: If a cooling coil drops air below its dew point, mist can form in ducts.
  • Feature: After calculating coil exit conditions (using ThermExcel’s standard coil module), Psychrosi runs a check:
    • Exit DB vs Exit WB. If DB - WB < 0.2°C → "⚠️ Near saturation – risk of duct fogging / carryover" .
    • Suggests: "Increase coil face velocity or reduce fin density."

3.2 Thermexcel’s Modeling Approach

Thermexcel solves the following for each coil row and segment: thermexcel programme psychrosi

  • Sensible heat transfer: Q_sens = m_dot_air * cp_air * (T_air_in - T_air_out)
  • Latent heat transfer: Q_lat = m_dot_air * h_fg * (W_in - W_out)
  • Total heat: Q_total = m_dot_air * (h_in - h_out)

The software uses the ε-NTU method extended to dehumidifying coils, with correlations for:

  • Colburn j-factor for heat transfer
  • Friction factor f for pressure drop
  • Mass transfer analog (Chilton-Colburn analogy)

What is the Thermexcel Psychrosi Program?

At its core, the Thermexcel Psychrosi program is a calculation tool designed to determine the thermodynamic properties of moist air. It operates within the familiar interface of Microsoft Excel, making it accessible to engineers and technicians who don't have time to learn complex standalone software. Thermexcel is a known software tool developed by

The program is built to calculate essential parameters such as:

  • Dry Bulb Temperature
  • Wet Bulb Temperature
  • Relative Humidity
  • Dew Point
  • Specific Enthalpy
  • Specific Volume
  • Vapor Pressure

1. HVAC Coil Selection

Engineers use ThermExcel to determine if a standard coil can achieve required dehumidification. If the calculated leaving humidity ratio is too high, you must lower the ADP (colder chilled water) or decrease the BPF (more coil rows/fins). Given this, the most plausible interpretation is that

5.2 Evaporative Cooling

Thermexcel does not directly model evaporative pads (direct evaporative cooling). It models cooling coils only. For indirect evaporative cooling, a secondary air stream can be defined, but it is not psychrometrically coupled.

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