ME ThermoTools — Ebora

❄️ ME ThermoTools

Your all-in-one property toolkit for Air Conditioning & Ventilation. Get moist-air properties, steam tables, refrigerant tables, and air ideal-gas data — with the formulas and a psychrometric chart to learn from. Free to use.

Units

Free to use

How to use: Enter the dry-bulb temperature and relative humidity of the air. Tap Compute to get every moist-air property, plotted on a psychrometric chart. Assumes standard atmospheric pressure (101.325 kPa).

Dry-bulb temperature ?

°C

Relative humidity ?

Moist-air properties

Psychrometric chart — saturation curve (100% RH) with 20/40/60/80% RH lines. ● marks your air's state point.

Show formulas

Standard atmospheric pressure p = 101.325 kPa. With dry-bulb T and relative humidity φ:

p_ws = saturation pressure at T (ASHRAE)

p_w = φ · p_ws (vapor pressure)

W = 0.621945 · p_w / (p − p_w) (humidity ratio)

μ = W / W_s (degree of saturation; W_s at same T)

h = 1.006·T + W·(2501 + 1.86·T) kJ/kg dry air (SI)

v = 0.287042·(T+273.15)·(1+1.6078·W) / p m³/kg (SI)

Dew point = temperature where p_ws equals p_w. Wet-bulb is solved from the adiabatic-saturation energy balance. Density ρ = (1+W)/v.

How to use: Pick the region, choose what you know, and type its value. Saturated: enter a temperature or a pressure → get both phases. Superheated: enter pressure and temperature. Values are interpolated between published table rows.

Region

Look up by

Saturation temperature

°C

Water / steam properties

Show notes & interpolation

Saturated data is the steam table indexed by either temperature or pressure (they are tied along the saturation line). Linear interpolation between rows:

y = y₀ + (y₁−y₀)·(x−x₀)/(x₁−x₀)

Internal energy is taken from the table where listed. For refrigerants and superheated rows it is also given directly. Saturated water range: 0.01 → 374 °C (triple point → critical). Superheated range: ~0.7 → 100 bar.

Data: standard steam tables (Moran/Cengel-class; saturation + superheated). Verify against the exact table your course prescribes — different editions differ in the last digit.

How to use: Choose a refrigerant and region, then look up by temperature or pressure. R-134a has both saturated and superheated tables; R-22 and R-410A are saturated only (superheated coming soon).

Refrigerant Region

Look up by

Saturation temperature

°C

Refrigerant properties

Show notes & reference states

Enthalpy/entropy are relative to a reference state that differs by source:

R-134a — h_f = 0 at −40 °C (textbook reference).
R-22, R-410A — h = 200 kJ/kg, s = 1.00 kJ/kg·K for saturated liquid at 0 °C (IIR reference).

Differences within one refrigerant's table are always valid for cycle work; never subtract enthalpies between different refrigerants.

Data sources — R-134a: Moran/Cengel tables. R-22: published saturation table (AGC). R-410A: NIST REFPROP via Arkema. Confirm against your course's tables.

How to use: Enter an air temperature. The app returns the ideal-gas air properties (enthalpy h, internal energy u, standard entropy s°, relative pressure P_r, relative volume v_r) interpolated from the gas table. Use P_r and v_r as ratios for isentropic processes.

Air temperature ?

°C

Ideal-gas air properties

Show notes

Ideal-gas air table (low-pressure, temperature-dependent). For an isentropic process use the relative properties:

P₂/P₁ = P_r2 / P_r1 v₂/v₁ = v_r2 / v_r1

P_r and v_r are dimensionless reference quantities — only their ratios are meaningful (valid in SI or Imperial). Table range: 200 → 1000 K.

Data: standard ideal-gas properties of air (Table A-17 class). Range 200–1000 K.

📖 Glossary of terms

Dry-bulb temperature (T_db): The air temperature read by an ordinary thermometer.
Wet-bulb temperature (T_wb): Temperature reached by evaporative cooling at constant pressure; read by a thermometer with a wetted wick.
Dew point (T_dp): Temperature at which air becomes saturated and water starts to condense.
Humidity ratio (W): Mass of water vapor per unit mass of dry air (kg/kg or lb/lb).
Relative humidity (φ): Vapor pressure ÷ saturation pressure at the same temperature, in %.
Degree of saturation (μ): W ÷ W_s (saturation humidity ratio at the same temperature).
Specific enthalpy (h): Energy content per unit mass; used for heating/cooling load energy balances.
Specific volume (v): Volume per unit mass (m³/kg or ft³/lb).
Saturated liquid / vapor (f / g): Subscript f = saturated liquid, g = saturated vapor; h_fg = latent heat of vaporization.
Superheated: Vapor heated above its saturation temperature at that pressure.
P_r, v_r: Relative pressure and relative volume from the air table; use as ratios for isentropic processes.