PROJECT INFORMATION
Client project or zone identifier
Drawing or document reference
Responsible engineer
Site or city
Equipment or system reference
Calculation date
Optional — duty notes or design basis
SystemReference and Calculation Method
Reference only. Saturation values come from a published PT source.
Calculation method
Enter saturation temperatures from your gauge app, PT chart, or calibrated refrigerant software.
Saturation Reference indicative
Refrigerant: —
Gauge pressure
kPa(g)
—
Quick pressure → saturation-temperature lookup for the selected refrigerant. Indicative cross-check — always verify against your calibrated gauge. Full bidirectional reference & accuracy notes ↓
Suction SideEvaporator / Low Side
°C
From gauge app, PT chart, or calibrated refrigerant software.
Enter a valid number.
°C
Contact probe or clamp-on thermometer.
Enter a valid number.
Evaporator Superheat
—
— K
Liquid SideCondenser / High Side
°C
From gauge app, PT chart, or calibrated refrigerant software.
Enter a valid number.
°C
Contact probe or clamp-on thermometer.
Enter a valid number.
Liquid Subcooling
—
— K
Diagnosis Results
Superheat
— K
Subcooling
— K
Suction Sat. Temp.
— °C
Suction Line Temp.
— °C
Condensing Sat. Temp.
— °C
Liquid Line Temp.
— °C
Superheat Status
—
Subcooling Status
—
SH vs Target
—
SC vs Target
—
Broad bands are informational only. These ranges do not account for system type, metering device, operating conditions, refrigerant, load, airflow, or manufacturer requirements. Use manufacturer data for target values. The broad ranges apply to single-stage vapour-compression systems; VRF / VRV, transcritical CO₂ (R-744), multi-stage, and cascade systems have different targets — always refer to manufacturer service data and control logic.
OPTIONAL
Target Comparison
LIVECycle Property Snapshot
T-s
Temperature × Entropy
P-h
Pressure × Enthalpy · Mollier
Values update live · diagrams illustrative
EVAPORATOR · LOW PRESSURE SIDE
T_sat,e (saturation)—
T_suct (line)—
Superheat SH = T_suct − T_sat,e——
CONDENSER · HIGH PRESSURE SIDE
T_sat,c (saturation)—
T_liq (line)—
Subcooling SC = T_sat,c − T_liq——
SUMMARYCycle State Summary
| Quantity | Symbol | Value | Engineering meaning |
|---|---|---|---|
| Evaporator saturation | T_sat,e | — | Phase-change temperature on the low-pressure side. Read from PT chart, gauge app, or manifold. |
| Suction line | T_suct | — | Pipe temperature at suction probe location, downstream of evaporator outlet. |
| Superheat (calc) | SH = T_suct − T_sat,e | — | Vapour above evaporator saturation at the measurement point. |
| Condensing saturation | T_sat,c | — | Phase-change temperature on the high-pressure side. Read from PT chart, gauge app, or manifold. |
| Liquid line | T_liq | — | Pipe temperature at liquid probe location, downstream of condenser outlet. |
| Subcooling (calc) | SC = T_sat,c − T_liq | — | Liquid below condensing saturation at the measurement point. |
CONTEXT
Interpretation
Positive superheat at the measurement point indicates suction vapour is above local saturation temperature. Compressor-inlet protection from liquid phase depends on actual compressor-inlet measurement and manufacturer limits. Superheat = measured suction line temperature minus suction saturation temperature.
Positive subcooling confirms liquid refrigerant is cooled below condensing saturation temperature, helping ensure a liquid column free of flash gas at the expansion device. Subcooling = condensing saturation temperature minus measured liquid line temperature.
Refrigerant selection is recorded for reference only. Saturation temperatures are entered from a published pressure-temperature source; an optional built-in PT reference provides an indicative cross-check only and is not used as the charging authority.
This calculator does not determine refrigerant charge, diagnose component failure, replace manufacturer service data, or verify system safety. Broad diagnostic ranges are informational only. Manufacturer targets and operating conditions govern final interpretation.
DENOVA
Practical Engineering Software
Superheat / Subcooling
Prepared by
—
—
Checked by
—
—
Issue purpose
PREVIEW ONLY
Status
Preliminary · Verification required
Design Conditions
Calculation Summary
Superheat
—
—
Subcooling
—
—
—
Calculation Method
Superheat
SH = Tsuction − Tsat,evap
Suction-line vapour temperature measured above the evaporator saturation temperature.
Subcooling
SC = Tsat,cond − Tliquid
Condenser saturation temperature above the measured liquid-line temperature.
Saturation temperatures entered manually from a published PT chart, manufacturer software, or calibrated gauge.
Ref: ASHRAE Handbook—Refrigeration (2022 methodology basis), Chapter 1 · Manufacturer service data where applicable.
Measurement Data
| Parameter | Location / Source | Value |
|---|---|---|
| Evaporator / Suction Side | ||
| Saturation temp. (evaporating) | PT chart / gauge app | — |
| Suction line temperature | Thermocouple / probe | — |
| Superheat | Calculated | — |
| Condenser / Liquid Side | ||
| Saturation temp. (condensing) | PT chart / gauge app | — |
| Liquid line temperature | Thermocouple / probe | — |
| Subcooling | Calculated | — |
Figure 1 · Refrigeration Circuit — Measurement Points
Class B Flow Schematic · Measurement points annotated from entered field data
Figure 1: Class B Flow Schematic · Regenerated from field data · Measurement points annotated
Notes
[1] ASHRAE Handbook—Refrigeration (2022 edition used as methodology basis; verify latest edition for project use). Chapter 1: Refrigerant Data and Characteristics.
[2] ASHRAE Handbook—Fundamentals (2021). Chapter 1: Psychrometrics; Chapter 6: Mass Transfer.
[3] Manufacturer Service Data — where applicable. Saturation data must be cross-checked against published PT charts.
[4] Refrigerant property values, glide magnitudes, and safety classifications are indicative values compiled from NIST Reference Fluid data (REFPROP) and ASHRAE Standard 34. Verify against NIST / manufacturer data for critical work.
Examples: Copeland Application Engineering Bulletins · Daikin Service Manuals · Bitzer / Carlyle / Bristol compressor envelope data. Final target values must come from the equipment manufacturer.
[2] ASHRAE Handbook—Fundamentals (2021). Chapter 1: Psychrometrics; Chapter 6: Mass Transfer.
[3] Manufacturer Service Data — where applicable. Saturation data must be cross-checked against published PT charts.
[4] Refrigerant property values, glide magnitudes, and safety classifications are indicative values compiled from NIST Reference Fluid data (REFPROP) and ASHRAE Standard 34. Verify against NIST / manufacturer data for critical work.
Examples: Copeland Application Engineering Bulletins · Daikin Service Manuals · Bitzer / Carlyle / Bristol compressor envelope data. Final target values must come from the equipment manufacturer.
This tool calculates superheat and subcooling directly from the saturation and line temperatures you enter, using the standard field definitions (SH = suction line − suction saturation; SC = liquid saturation − liquid line). Results are reference-only and do not constitute a compliance statement, equipment certification, or maintenance instruction. Accuracy depends on your inputs: saturation temperatures must come from a published PT chart, manufacturer software, or a calibrated electronic gauge, and any measurement error carries directly into the result. Final target values for superheat, subcooling, and approach are set by the equipment manufacturer (OEM application bulletins, service manuals, or compressor-envelope data). A qualified refrigeration technician or engineer must interpret and act on these results.