ITC Tonnage Input Form
Example Data Table
| Input Item | Example Value | Purpose |
|---|---|---|
| Direct cooling load | 60,000 BTU/hr | Base ITC heat load |
| Equipment load | 8 kW | Electrical heat released indoors |
| Ventilation | 300 CFM at 20°F difference | Outdoor air sensible load |
| Diversity, safety, derating | 100%, 10%, 95% | Design correction factors |
| Electrical supply | 415 V, three phase, 0.90 PF | Running current estimate |
Formula Used
Equipment heat: equipment kW × 3412.142 × heat factor.
Lighting heat: lighting kW × 3412.142 × heat factor.
People heat: people count × heat per person.
Ventilation sensible load: 1.08 × CFM × temperature difference.
Subtotal load: direct load + equipment heat + lighting heat + people heat + ventilation load + latent load.
Adjusted load: subtotal × diversity factor × safety factor ÷ derating factor.
ITC tonnage: adjusted BTU/hr ÷ 12,000.
Compressor input: adjusted BTU/hr ÷ EER ÷ 1000.
Single phase current: watts ÷ voltage ÷ power factor ÷ efficiency.
Three phase current: watts ÷ 1.732 ÷ voltage ÷ power factor ÷ efficiency.
How To Use This Calculator
Enter the known cooling load first. Select its unit carefully.
Add electrical equipment and lighting load. Use heat factors when only part of a load releases heat indoors.
Add people, ventilation, latent load, diversity, margin, and derating values.
Enter EER, fan load, auxiliary load, voltage, phase, power factor, and efficiency.
Press the calculate button. The result appears above the form and below the header.
Use CSV or PDF buttons to save the calculation summary.
ITC Tonnage Planning Guide
What Is ITC Tonnage?
ITC tonnage links cooling duty with electrical demand. It helps size an indoor thermal cooling unit, panel allowance, feeder load, and starting current. The tool converts heat load into tons of refrigeration. It then checks how that capacity affects running current and breaker planning.
Why Electrical Inputs Matter
A cooling unit is not chosen by tons alone. Voltage, phase, power factor, efficiency, and EER change the expected amperage. A three phase supply usually carries the same kilowatts with lower line current. Poor power factor raises current. Low efficiency also raises current. These values help engineers compare the cooling result with practical electrical limits.
How Load Components Are Added
The calculator accepts a direct cooling load. It also adds equipment heat, lighting heat, people heat, ventilation heat, and latent heat. Electrical equipment and lights usually become heat inside the cooled space. Ventilation load depends on airflow and temperature difference. Latent load covers moisture removal. These parts create a more realistic ITC load.
Adjustment Factors
Real projects need margins. Diversity reduces load when not everything runs together. Safety margin covers future load, weather, fouled filters, or design uncertainty. Derating corrects for harsh ambient conditions, altitude, weak airflow, or installation losses. The adjusted load is the value used for final tonnage.
Interpreting The Result
One refrigeration ton equals 12,000 BTU per hour. The result shows total BTU per hour, cooling kilowatts, refrigeration tons, and the next half ton size. It also estimates compressor input power from EER. Running current, starting current, and breaker current are then shown. These outputs are planning estimates, not a substitute for nameplate data.
Best Use Cases
Use this calculator during early design, load comparison, retrofit checks, and quick feasibility studies. It is useful when a room has mixed electrical equipment, lighting, staff, and outdoor air. Always verify the final selection with manufacturer data, local code, cable temperature rating, installation method, and protection rules. For critical systems, add redundancy and review heat rejection. Keep notes for assumptions, because small input changes can shift final capacity and amperage. Document the selected standard size, expected duty cycle, and measured site voltage. These records make later troubleshooting faster and help maintenance teams compare actual performance over time.
FAQs
What does ITC tonnage mean here?
It means the estimated cooling tonnage needed for an indoor thermal cooling load, linked with electrical planning values like current, breaker demand, and input power.
Why is one ton equal to 12,000 BTU/hr?
One refrigeration ton is a standard cooling capacity unit. It equals 12,000 BTU per hour and is widely used for air conditioning and cooling equipment sizing.
Can I use kW instead of BTU/hr?
Yes. Select kW, watt, kcal/hr, BTU/hr, or ton from the unit list. The calculator converts the direct load into BTU/hr internally.
What is the equipment heat factor?
It is the percentage of electrical equipment load released as heat into the cooled space. Use 100% when all consumed power becomes indoor heat.
Why is derating included?
Derating accounts for installation losses, high ambient temperature, altitude, restricted airflow, or other conditions that reduce practical cooling performance.
Is the breaker value final?
No. It is a planning current based on the calculated load. Always verify breaker sizing with nameplate data, cable rating, and local electrical rules.
Why does phase affect current?
Three phase supply spreads power across three lines. For the same voltage class and kilowatt load, line current is usually lower than single phase current.
Can this replace an engineer calculation?
No. It supports early planning and comparison. Final design should be checked by a qualified professional using manufacturer data and applicable standards.