Independent reference · every claim sourced

Liquid cooling, made checkable.

GPU racks crossed 100 kW and air cannot follow. One concept per page — formulas with real numbers, live calculators, sourced product data — for engineers and buyers who verify instead of trust.

⚡ Open the playground Start the guide →

Live — drag the point along the curve

50.0 kW

what a 50 kW-class liquid-to-air cabinet can still reject at 25 °C room air

ROOM 25 °C

Drag toward the tropics: hotter room, smaller approach, less capacity — the one piece of physics this whole site exists to make obvious →

DATA v2026-10-12PRODUCTS 09-09VENDORS 10-08FORMULAS 10-08CHANGELOG →

FORMULAS × 11

Verifiable

Every formula with worked examples and a live calculator — real numbers you can check, not marketing curves.

97 COMPANIES · 16 SEGMENTS

Sourced

Product and supply-chain data linked to official sources on every row; unverifiable data is marked, never invented.

4 TOOLS · ALL IN-BROWSER

Interactive

Rack builder, derating simulator, room-load calculator and an animated coolant loop — learn by moving numbers.

Start

What is liquid cooling?Cold plates, CDUs, manifolds, quick disconnects — the parts and the physics, with a live loop simulator→What is a CDU?The heart of the system: pumps, heat exchangers, TCS vs facility loops, the three form factors→Cold plate vs immersionThe two architectures compared: heat capture, fluids, PFAS regulation, serviceability→Liquid vs airWhere the crossover really is, what PUE numbers assume, and the tropical catch nobody mentions→

Formulas

One formula per page: definition → worked example with real numbers → live calculator → the mistakes that cost money.

Coolant flow rateL/min = kW × 60 / (4.186 × ΔT) — 50 kW at ΔT 8 °C → 89.6 L/min→Heat capture splitP_liq = capture × P_IT — 60-80% leaves through liquid; the rest still heats the room→TDP → rack kWP_rack ≈ nodes × (Σ GPU + Σ CPU) × 1.2 — chip power to a rack budget→Room AC loadP_AC ≈ 1.1 × P_IT — 30 kW rack → 33 kW ≈ 9.4 tons of room cooling→kW ↔ refrigeration tons1 ton = 3.517 kW = 12,000 BTU/h — cooling units ≠ electrical draw→Approach temperaturecapacity ≈ rated × approach / 20 K — why 35 °C halves a 50 kW cabinet→Pressure dropΔP = f × (L/D) × ρv²/2 — 90 L/min in 25 mm hose loses ≈20 kPa over 3 m→Floor loadingkN/m² = kg × 9.81 ÷ m² — a full rack prints ~5× an office floor's rating→PUE mathPUE = total ÷ IT energy — 1.05-1.2 liquid vs 1.4-1.6 air, and what the number hides→ASHRAE W-classesW17 · W27 · W32 · W40 · W45 — the number ≈ max facility water supply °C→Wet-bulb & free coolingfree cooling ⇔ wb + 6 K ≤ coolant °C — why the tropics can't economize→

Choosing

Cabinet comparisonEvery small-scale cooling cabinet we could verify — power class, cooling type, facility needs, per-row sources→What drives the costWhy nobody publishes prices, the cost stack, and how to make quotes comparable→RFQ scope checklistTwelve line items that turn two incomparable quotes into one comparable table→Liquid-ready serversThe five compatibility checks — plates, couplings, W-class, flow, serviceability→Hot & tropical climatesDerating physics with published numbers, SS 726:2026 scope, the buying checklist→

Immersion cooling tank with server blades in dielectric fluid — AI illustration — PLATE 2 — The other architecture: single-phase immersion, blades bathed in dielectric fluid. AI-generated illustration (Z-Image Turbo) — representative, not a specific product. Compared honestly in cold plate vs immersion.

Deploy & Ops

Site surveySix-point checklist — floor, power, heat egress, water, access, noise — each linked to its math→Room load calculationCan your room host an L2A cabinet? The 1.1× rule, worked hospital example, full survey→CommissioningEight steps from empty pipes to signed acceptance→Leaks: risk & responseWhere leaks actually happen, and the four-layer detection model to demand→Maintenance scheduleWeekly-to-annual intervals that keep a coolant loop boring→

Reference

Supply chain map97 companies across 16 segments, chips to heat rejection — every row sourced; free listings, never paid→Industry radarNews plus the curated milestone timeline — every item sourced, nothing invented→State of 2026The annual digest: what changed, and the 20-50 kW turnkey gap that still doesn't exist→Glossary50+ self-contained, anchorable definitions — DLC, UQD, W-class, approach temperature…→UQD quick disconnectsThe OCP coupling family UQD04-UQD40, tabulated by nominal flow→Fluids & PFASPG25 vs oils vs fluorinated fluids — chemistry as a buying decision→StandardsOCP, ASHRAE W-classes, IEC 62368-1, SS 726 — mapped to a buying checklist→ChangelogData-layer versions and article updates→