Why do liquid cooling quotes vary so much?

Because the scope underneath the number varies: rated capacity quoted at different ambient temperatures, redundant pumps in one quote and single in another, monitoring included or not, commissioning and certification in or out. Pin twelve line items — capacity at your conditions, capture ratio, redundancy, interconnects, monitoring, acceptance testing, service — and the price gap becomes explainable or disqualifying.

What is the most important question in a liquid cooling RFQ?

Capacity at your actual room design temperature, in writing. Nameplate figures are quoted at 25 °C air / 45 °C coolant; at 35 °C ambient an L2A cabinet delivers roughly half. Vendors who cannot provide a capacity-vs-ambient curve for their own product are answering a different question.

Choosing · 2 min read

RFQ scope checklist

Nobody in this segment publishes prices — so quotes are only comparable if the scope is pinned. Send this checklist with every RFQ and require answers in writing; it converts "quote for a liquid cabinet" into twelve defined line items (why prices hide).

#	Line item	The question that pins it
1	Capacity @ conditions	kW rejected at your room design temp and stated coolant temp — nameplate at 25 °C does not count (derating)
2	Heat capture	What % of IT heat goes to liquid in this configuration; what stays on air (split)
3	Facility interfaces	Power feeds (kW, redundancy), floor load print (kN/m²), water/none, room AC requirement (1.1×, floor)
4	Redundancy	Pumps N+1? Fans? Controls? What fails how gracefully — and what does the cabinet do on facility power loss
5	Interconnects	UQD and manifold spec/version — ORv3 blind-mate or proprietary (UQD, lock-in defense)
6	Fluid & warranty terms	Shipped fluid spec (PG25?), who owns chemistry compliance, what voids the warranty (fluids)
7	Monitoring scope	Sensors included (flow, ΔP, leak, level, temperature), protocols/BMS integration, alarm routing (leak layers)
8	Leak containment & response	Dripless couplings, drain/containment capacity, interlock actions on leak detect
9	Certifications	CE/UL/IEC 62368-1 Ed.4 and your market's local listing — per-region confirmation in writing (standards)
10	Commissioning & acceptance	Vendor runs the 8-step commissioning; acceptance = measured flow/ΔT/capacity at your conditions (sequence)
11	Service model	Response SLA, spares on site, maintenance contract scope vs schedule, training for your staff
12	Derating documentation	Capacity-vs-ambient curve or table in writing — the vendors who can't provide it are telling you something (why)

FIG. 1 — Twelve lines that make two quotes comparable. Items 1, 4 and 12 are where most "mysterious" price gaps live.

How to run it

Send the table as a mandatory annex; "see datasheet" is not an answer to item 1 or 12.
Score vendors on the comparison table after answers arrive — gaps become visible, e.g. the 20-50 kW turnkey void.
Walk the site with the survey checklist before the RFQ so items in line 3 are your numbers, not the vendor's assumptions.

What drives the cost · Cabinet comparison · Standards

Sources

Checklist compiled from this site's engineering pages; each line links the page that explains the underlying physics or standard.

RFQ scope checklist

How to run it

Related

Sources