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Conversion

Refrigeration Ton Converter (Ton ↔ kW ↔ BTU/h ↔ kcal/h)

A **ton of refrigeration (TR / RT)** comes from the 19th-century ice industry — the heat-removal rate of one short ton (2 000 lb) of ice melting at 32 °F over 24 hours. **ANSI/IIR R-1 defines 1 TR ≡ 12 000 BTU/h ≈ 3.517 kW.** This tool converts between *cooling capacity* units — TR, kW, BTU/h, kBTU/h, kcal/h (= frigorie/h) and mechanical hp — and shows every unit live. **Uses**: (a) **HVAC specs** — US engineers write TR and BTU/h, Europe / Japan / China use kW; you need to bridge for designs and procurement; (b) **data-centre cooling** — IT load (kW) becomes heat that must be matched 1:1 by cooling capacity (and divided by PUE for total electrical demand); (c) **chiller capacity** — a 100-ton commercial unit ≈ 351.7 kW; (d) **AC labels** — US window units typically rated 5 000–24 000 BTU/h, i.e. 0.42–2 TR.

Live capacity in every refrigeration unit

kW Kilowatt (SI)
TR US ton of refrigeration (TR / RT)
BTU/h BTU per hour (IT)
kBTU/h Thousand BTU/h (kBTU/h)
kcal/h Kilocalorie per hour (kcal/h)
hp Mechanical horsepower (hp, 745.7 W)

Refrigeration capacity describes the *heat removal rate*, not electrical input. AC power draw = capacity ÷ EER (or ÷ COP). Example: 1 TR ≈ 3.517 kW of cooling at a COP of 3.5 draws about 1 kW of electricity.

  • TR North-American HVAC, room ACs and chillers (1 TR ≡ 12 000 BTU/h ≈ 3.517 kW)
  • kW SI / European HVAC design, data-centre heat load, heat-pump specs
  • BTU/h US residential AC labels (window units typically 5 000–24 000 BTU/h)
  • kBTU/h US commercial HVAC loads and mechanical drawings
  • kcal/h Older European / Japanese ratings (1 kcal/h = 1 frigorie/h)
  • hp Small compressors, refrigerated-truck units rated in mechanical hp

Formula

Reference: 1 TR ≡ 12 000 BTU/h (IT, ANSI/IIR R-1, exact definition) ≈ 3.516 852 84 kW ≈ 3 023.949 kcal/h ≈ 4.716 hp (mechanical) Each unit → kW: 1 kW = 1 kW (SI reference) 1 TR = 3.516 852 84 kW (exact) 1 BTU/h = 0.000 293 071 070… kW (IT BTU) 1 kBTU/h = 0.293 071 070… kW = 1000 × BTU/h 1 kcal/h = 1.163 × 10⁻³ kW (exact, 1 cal_IT = 4.1868 J) 1 hp_mech = 0.745 699 871 582 kW (NIST, exact) Relation: electrical power (kW) = cooling capacity (kW) / COP COP = EER (BTU/h per W) / 3.412 (e.g. EER 12 → COP ≈ 3.51)

Frequently asked

My home AC is rated 12 000 BTU/h — how many tons is that and how much power does it draw?

**12 000 BTU/h = 1 TR = 3.517 kW of cooling**. Power draw depends on efficiency: (a) EER 10 (typical baseline) → 12 000 ÷ 10 = **1 200 W = 1.2 kW** (COP ≈ 2.9); (b) EER 12 (efficient) → **1 000 W = 1 kW** (COP ≈ 3.5); (c) EER 14 (top-tier inverter) → **857 W ≈ 0.86 kW** (COP ≈ 4.1). **Daily energy cost** (8 hours continuous, US$0.15 / kWh): 1.2 kW × 8 × $0.15 = **$1.44 /day**; efficient inverter drops to **$1 /day**. **Reading the label**: "12 000 BTU" is *cooling*; "1.2 kW" could be either *cooling* (European convention) *or* *power input* (US power-supply field) — always check context. Chinese-market labels separately state "Cooling 3 500 W / Rated input 1 100 W".

A data-centre room has 50 kW of IT load — how many tons of cooling is needed?

**First principle: IT load converts almost entirely to heat**, so cooling needed ≈ IT load. 50 kW IT → **50 kW of cooling = 50 ÷ 3.517 ≈ 14.2 TR**. **In practice you size higher**: (a) **lighting + envelope gains** ≈ +5–10 %; (b) **UPS losses** (85–95 % efficient) ≈ +5–10 %; (c) **redundancy** (N+1 or 2N) → ×2 design load; (d) **future growth** +20–30 %; the *installed* capacity may reach **30–40 TR**. **PUE (Power Usage Effectiveness) is the more practical metric**: PUE = total room power ÷ IT power. **Typical values**: (a) legacy rooms PUE 2.0 (cooling consumes as much as IT); (b) modern data halls 1.3–1.5; (c) hyperscale (Google) ~1.1. **Example**: 50 kW IT × PUE 1.4 = 70 kW total, of which 20 kW drives cooling ≈ 5.7 TR of *compressor power* (the cooling capacity itself is much higher: 70 kW × COP 3.5 = 200 kW = 57 TR of heat removed and recirculated). The IT-kW = cooling-kW rule of thumb still anchors the first pass.

How does a SEER-20 rating translate to COP, and what is the practical power draw of a 1-TR unit?

**SEER ↔ COP conversion**: (a) **direct formula** COP_avg = SEER / 3.412 (BTU/h ÷ W); (b) SEER 20 → COP_avg ≈ **5.86**; (c) **but SEER is a *seasonal* mean** including part-load operation; *peak* COP at steady-state max cooling is typically ~20 % lower, so a SEER-20 unit peaks at COP ≈ 4.7. **Practical power draw of a 1-TR (12 000 BTU/h) unit**: (a) **legacy SEER 10** (COP_avg 2.93) → 1 200 W average; (b) **mainstream SEER 14** (COP_avg 4.10) → 850 W; (c) **efficient SEER 20** (COP_avg 5.86) → **600 W**; (d) **top-tier SEER 26** (inverter + R-32, 2024 Daikin models) → 460 W. **Annual savings** going SEER 10 → 20 over 800 cooling hours: (1 200 − 600) × 800 / 1 000 × US$0.15 = **$72 / year** (~$720 over 10 years). **Caveat**: the SEER metric was revised in 2015 (SEER₂ / EER₂, AHRI 210/240-2023) to include a 25 Pa external-static correction; new and old SEER numbers differ by ~4.5 %, so make sure to compare like with like.

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