{
 "id": "5.07",
 "slug": "rear-door-heat-exchangers",
 "url": "/parts/liquid-cooling-it-side-chip-to-cdu/rear-door-heat-exchangers",
 "name": "Rear-door heat exchangers",
 "qualifiers": null,
 "layer": {
  "id": 5,
  "name": "Liquid cooling (IT-side: chip to CDU)"
 },
 "parent_id": null,
 "children": [],
 "summary": "A heat exchanger mounted on the rear door of a server rack that cools exhaust air with chilled water or refrigerant before it leaves the rack, without cooling the chips directly.",
 "description_md": "The rear-door heat exchanger is an air-assist approach rather than a direct-to-chip one: it sits behind a rack of otherwise air-cooled servers and pulls heat out of the exhaust air using a chilled-water or refrigerant coil before that air re-enters the room, rather than cooling the die directly the way a cold plate does. It is typically deployed where a facility wants to raise the density it can support without redesigning every server for direct liquid cooling, or as a supplement in racks that mix liquid-cooled accelerators with air-cooled networking and storage. Because it works at the rack-exhaust level rather than the die level, it has a lower cooling ceiling than a direct-to-chip loop and is generally positioned as a bridge or hybrid option rather than the primary cooling path for the highest-density AI racks. Investors should watch it as a hybrid-density play: demand depends on how much of the installed base stays on air or mixed cooling rather than converting fully to direct-to-chip.",
 "ai_delta": null,
 "bottleneck_status": null,
 "scale_tiers": [
  "enterprise",
  "hyperscale_building"
 ],
 "density_modes": [
  "hybrid"
 ],
 "scale_notes": "Used as a hybrid or bridging measure in mixed air/liquid racks or facilities not built for full direct-to-chip cooling; less common at the highest-density AI campus and GW-class builds, which favor direct-to-chip.",
 "flow": [
  "heat"
 ],
 "companies": [
  {
   "company_id": "legrand",
   "name": "Legrand",
   "role": "manufacturer",
   "confidence": "inferred",
   "ownership_type": "public",
   "ticker": "LR.PA",
   "product_note": null,
   "note": null,
   "source_url": null
  },
  {
   "company_id": "motivair",
   "name": "Motivair",
   "role": "manufacturer",
   "confidence": "inferred",
   "ownership_type": "subsidiary",
   "ticker": null,
   "product_note": null,
   "note": null,
   "source_url": null
  },
  {
   "company_id": "nvent",
   "name": "nVent",
   "role": "manufacturer",
   "confidence": "inferred",
   "ownership_type": "public",
   "ticker": "NVT",
   "product_note": null,
   "note": null,
   "source_url": null
  },
  {
   "company_id": "vertiv",
   "name": "Vertiv",
   "role": "manufacturer",
   "confidence": "inferred",
   "ownership_type": "public",
   "ticker": "VRT",
   "product_note": null,
   "note": null,
   "source_url": null
  },
  {
   "company_id": "coolcentric",
   "name": "Coolcentric",
   "role": "manufacturer",
   "confidence": "inferred",
   "ownership_type": "private",
   "ticker": null,
   "product_note": null,
   "note": null,
   "source_url": null
  },
  {
   "company_id": "huawei",
   "name": "Huawei",
   "role": "manufacturer",
   "confidence": "inferred",
   "ownership_type": "private",
   "ticker": null,
   "product_note": null,
   "note": null,
   "source_url": null
  },
  {
   "company_id": "rittal",
   "name": "Rittal",
   "role": "manufacturer",
   "confidence": "inferred",
   "ownership_type": "private",
   "ticker": null,
   "product_note": null,
   "note": null,
   "source_url": null
  },
  {
   "company_id": "stulz",
   "name": "Stulz",
   "role": "manufacturer",
   "confidence": "inferred",
   "ownership_type": "private",
   "ticker": null,
   "product_note": null,
   "note": null,
   "source_url": null
  }
 ]
}