Submer Technologies

Summary

Submer Technologies is a Barcelona, Spain-based single-phase immersion cooling company founded in 2015 by Daniel Pope and Pol Valls Soler. It is one of the leading independent pure-plays in liquid immersion cooling for datacenters — a market that has moved from niche to mainstream as AI accelerator rack densities exceed what air cooling can handle. Submer’s core products are its SmartPod immersion tanks and SmartCoolant proprietary dielectric fluid. The company raised $55.5M in Series C funding in October 2024 at a $500M valuation, led by M&G Investments. Its customer base includes at least one unnamed hyperscaler, Telefónica, ExxonMobil, and the European Commission. Submer is also developing ADA, an autonomous robot designed to insert and remove servers from immersion tanks — see submer-ada.md.

Key Facts

Founded: 2015
HQ: Barcelona, Spain
Type: Private
CEO: Patrick Smets (joined as COO August 2023; became CEO January 2024)
Co-Founders: Daniel Pope and Pol Valls Soler
Total funding: ~$110M across 7+ rounds (Series C $55.5M Oct 2024 + $20.9M debt Dec 2024)
Valuation: ~$500M (at Series C, October 2024)
Series C lead: M&G Investments; participants include Mundi Ventures, Planet First Partners, Norrsken VC
Core products: SmartPod (single-phase immersion tank), SmartCoolant (proprietary dielectric fluid), SmartMod (prefabricated modular datacenter unit incorporating SmartPod)
Coolant: SmartCoolant — proprietary synthetic, biodegradable, non-flammable, non-toxic, water-viscosity, non-ozone-depleting; designed for long service life between changes
PUE range (design): 1.02–1.03 (immersion cooling nearly eliminates mechanical cooling overhead)
Supported rack density: Up to 200+ kW per tank (AI GPU configurations)
Robotics program: ADA (Autonomous Datacenter Assistant) — vertical-lift robot for immersion tank servicing; revealed OCP Summit 2021, commercial target ~Q3 2025
Key customers (disclosed): At least one unnamed hyperscaler; Telefónica; ExxonMobil; European Commission; major HPC research centers
OCP alignment: Active participant in Open Compute Project; SmartPod design has OCP lineage

What It Is / How It Works

Submer’s SmartPod is a single-phase immersion cooling system. “Single-phase” means the dielectric fluid remains liquid throughout the heat exchange process — it absorbs heat from servers and is pumped to a heat exchanger (chiller, dry cooler, or facility water loop) where it releases heat before recirculating. This contrasts with two-phase immersion (e.g., LiquidStack), where the fluid boils and condenses — which achieves higher heat transfer coefficients but is more complex to manage and historically used fluorocarbon fluids with supply concerns (3M Novec line discontinued, though alternatives exist from Solvay and others).

SmartCoolant is Submer’s proprietary fluid and is the core product differentiation. Its key attributes:

Biodegradable: Derived from a synthetic blend designed to break down in the environment; addresses regulatory and ESG requirements
Non-toxic, non-flammable: Safe handling without hazmat protocols
Water viscosity: Server pumps and fans are designed for air or water; SmartCoolant’s similar viscosity to water means it doesn’t stress server components (though fans are typically disabled in immersion deployments)
Long change interval: Designed to remain stable for multi-year service intervals without degradation; reduces operational cost vs. frequent fluid changes

SmartPod tanks accommodate industry-standard servers (including OCP-format hardware) in a horizontal submersion configuration. The tank connects to a heat exchanger — at minimum a plate heat exchanger to building chilled water, or alternatively coupled to dry coolers, free cooling, or even heat recovery systems. Submer’s SmartMod product packages tanks, piping, power distribution, and monitoring into a prefabricated module for faster deployment.

The practical PUE of 1.02–1.03 in immersion systems comes from eliminating CRAC units, raised floors, and hot/cold aisle infrastructure. The only cooling-related power draw is the fluid pump, which is minimal. This compares to 1.3–1.5 PUE for well-designed air-cooled facilities and 1.1–1.2 PUE for direct-to-chip liquid cooling.

Operational friction: The tradeoff is servicing complexity. Servers submerged in fluid cannot be hot-swapped like rack-mounted units. Lifting a server from a tank requires PPE (dielectric fluid must be kept off skin and out of drains), vertical lift equipment, and fluid drip management. This is why Submer is developing ADA — without robotic assistance, immersion cooling scales better in density than in operational agility.

Notable Developments

2024-12: Submer raises $20.9M in conventional debt financing — additional capital beyond Series C. (Tracxn)
2024-10: Series C — $55.5M at $500M valuation; led by M&G Investments. Proceeds directed toward scaling manufacturing, expanding North America and Asia operations, and accelerating ADA robotics development. (TechCrunch)
2024-01: Patrick Smets promoted to CEO; co-founders Pope and Valls Soler shift to product/strategy roles.
2023-08: Patrick Smets joins as COO (first C-suite hire from outside founding team).
2021-10: ADA robotic assistant unveiled at OCP Global Summit 21. (Submer Labs / X)
2015: Founded in Barcelona by Daniel Pope and Pol Valls Soler.

Key People

Patrick Smets — CEO (since January 2024)

LinkedIn: linkedin.com/in/patricksmets (confirm; not independently verified in this review)
Role: CEO since January 2024; joined as COO August 2023
Background: Operations and scaling executive; recruited to bring operational discipline as Submer transitioned from early-stage startup to growth-stage company; not one of the technical founders
Notes: First externally recruited CEO; co-founders remain involved

Daniel Pope — Co-Founder

LinkedIn: linkedin.com/in/danielpope (confirm; common name, verify carefully)
Role: Co-founder; early CEO/Chief Visionary; current role title not confirmed post-Smets appointment
Background: Entrepreneur and datacenter sustainability advocate; co-created Submer’s vision of “datacenters that make sense” — combining efficiency, sustainability, and high density

Pol Valls Soler — Co-Founder

LinkedIn: Not confirmed; search for “Pol Valls Soler Submer” on LinkedIn
Role: Co-founder; technical and product leadership alongside Pope in founding years
Background: Engineering background; involved in SmartCoolant chemistry and SmartPod product development

People — Last Reviewed: 2026-03-24

Supply Chain Position

Submer sits at the Immersion Cooling System layer of the datacenter supply chain — designing tanks and fluid, integrating components, and delivering systems to datacenter operators and hyperscalers.

Layer	Detail
SmartCoolant raw materials	Proprietary synthetic blend; Submer does not disclose chemical suppliers; single-source risk if key precursors are from limited suppliers
Tank fabrication	Custom stainless or composite tank construction; likely outsourced to contract fabricators in Spain/Europe
Heat exchangers	Standard plate heat exchangers from Alfa Laval, Danfoss, or similar; commodity layer
Pumps and fluid management	Industrial pump suppliers (Grundfos, Xylem, or similar)
Sensors and monitoring	SmartCoolant monitoring instruments; likely third-party sensors integrated in Submer software
Submer’s position	Fluid chemistry (proprietary), system design, software monitoring, integration, and service
Customers (downstream)	Hyperscalers, telecoms, enterprise, HPC/research, government

⚑ SmartCoolant supply chain opacity: The chemical composition of SmartCoolant is proprietary and its upstream raw material supply chain is not disclosed. If key precursor chemicals are sourced from a limited number of suppliers (or from China), this is an unquantified risk. This is worth monitoring as Submer scales.

Competitive context: Submer’s primary direct competitor is LiquidStack (two-phase immersion; Wiwynn-backed). GRC (Green Revolution Cooling, Austin, TX; single-phase, ElectroSafe fluid) and Iceotope (chassis-level immersion, UK) are also in the market but with different system architectures. 3M’s discontinuation of Novec fluorocarbon fluids has created a gap in the two-phase market that benefits single-phase vendors including Submer, as operators concerned about two-phase fluid supply security consider single-phase alternatives.

Claim Verification

Claim: SmartCoolant is “biodegradable” and “non-toxic”

Status: Company-stated; no independent third-party certification published in public materials

Supporting:

Submer consistently describes SmartCoolant with these attributes across investor materials, product documentation, and press
The company markets to ESG-conscious enterprise and government customers where false environmental claims would carry reputational and legal risk
The general category of synthetic ester dielectric fluids (which SmartCoolant appears to belong to) does include genuinely biodegradable variants

Refuting / questioning:

Specific SDS (Safety Data Sheet) data and biodegradability test methodology (e.g., OECD 301B) are not publicly available
“Biodegradable” can range from readily biodegradable (>60% in 28 days) to ultimately biodegradable over years; Submer has not specified the standard used
Third-party environmental certification (ECOLOGO, Nordic Swan, etc.) has not been publicized

Summary: Claims are plausible for synthetic ester-type fluids but cannot be independently verified without SDS/test data. For operators with strict environmental compliance requirements, direct inquiry to Submer for certified test data is recommended.

Claim: PUE of 1.02–1.03

Status: Design-basis figure; operationally achievable but depends on facility configuration