Immersion Comparison

How does immersion cooling compare to air cooling and water cooling?

Air Cooling

Pros:

–Extremely well understood and quantified

–No additional cost

–Current OEM systems are designed for air cooling

–Equipment is easy to service

–No plumbing

–Good scaling from small to large

Cons:

–Extremely Noisy

–Requires more frequent maintenance

–Low density – higher cost for servers (per core)

–Inefficient – Fans waste 25% of IT power on DL380’s

–Large footprint

–More networking equipment

Single-Phase Immersion

Pros:

–Already well understood

–Simple control systems

–Up to 75% reduction in cooling power

–Engineered fluids are less expensive than two-phase

–Very high material compatibility

–Lenovo offer OEM warranty for servers

Cons:

–Equipment is covered in fluid when removed

–Not as efficient as two-phase

–Plumbing can get complex quickly

–Does not scale well to multi-megawatt sizes

–Requires larger, more expensive cooling coils

Two-Phase Immersion

Pros:

–High build quality by necessity

–Up to 98% reduction in cooling power

–Long life fluid (20 years)

–High cooling capacity (4kw per liter)

–Equipment is dry and clean when removed

–Fairly simple plumbing

–Excellent scaling

Cons:

–Not ideal at small scales

–Control costs are the same for 250kW and 10kW

–Controls are complex and expensive

–Cannot use HDDs

–Tanks must be stainless

–Fluids leak easily so quality control must be tightly adhered to

Direct to Chip Water Cooling

Pros:

–Well understood

–Up to 60% reduction in cooling cost

–Almost all servers can be modified

–Easy road to higher density

Cons:

–Still have fans

–Large footprint for plumbing and chillers

–Awful scaling – Infrastructure size grows faster with higher densities

–Greatly increased maintenance costs

–High additional cost

E3 NV has experience with air-cooled data centers, air-cooled modular data centers, several direct-chip-technologies, single-phase immersion, and most recently two-phase immersion. The info below is based on our real-world experience and the experiences of our customers.