Cooling is the single biggest mechanical challenge in a modern data center, and it has only gotten harder as AI workloads push rack densities higher and drive the move to liquid cooling. At the center of almost every cooling design sits a quiet, unglamorous component: the heat exchanger that separates one water loop from another. Get it right and the facility runs efficiently for years. Get it wrong and you have fouling, poor heat transfer, and a thermal bottleneck in the most expensive building your company operates. This guide covers how to think about heat exchanger selection for data center cooling.
Why a data center needs heat exchangers at all
A data center rarely runs a single water loop from the chiller all the way to the servers. Instead it uses separate loops, and heat exchangers transfer heat between them without letting the fluids mix. There are good reasons for the separation: the facility-side water (condenser water, cooling-tower water) is often dirtier or chemically treated differently than the clean, controlled water that runs near sensitive IT equipment. A heat exchanger lets the clean technical loop stay clean while still rejecting its heat to the facility loop.
With liquid cooling, this matters even more. Direct-to-chip and immersion cooling put a fluid loop extremely close to the electronics. That loop must be kept pristine and tightly controlled, and it is isolated from the facility water by a heat exchanger. As liquid cooling spreads, the number and importance of these isolating heat exchangers grows.
Why plate heat exchangers fit data centers
For liquid-to-liquid duty in a data center, the plate heat exchanger is usually the right tool. A plate heat exchanger uses a stack of thin corrugated metal plates to transfer heat between two fluids flowing in alternating channels. Compared with the older shell-and-tube design, plate units pack far more heat-transfer area into a much smaller, lighter footprint and can achieve closer temperature approaches, both of which matter when floor space is at a premium and efficiency is everything.
Where it fits in the GGC line card: We represent Sondex (Danfoss) heat exchangers. Sondex builds gasketed plate-and-frame units for standard liquid-to-liquid cooling duties, and plate-and-shell units that combine plate efficiency with higher pressure and temperature capability for tougher service. Plates are available in stainless 304 and 316 and in titanium, with other materials on request, so the unit can be matched to the water chemistry on each loop. The plate-and-frame design is well suited to the water-to-water cooling-loop and cooling-tower duties a data center runs.
What drives the selection
| Factor | Why it matters |
| Heat load (kW / tons) | Sets the required surface area and plate count. Size for the real peak, including future density growth. |
| Temperature approach | How close the two loops need to get in temperature. Plate units achieve close approaches, which improves efficiency. |
| Flow rates & pressure drop | Higher allowable pressure drop lets you use less surface; too much pressure drop burdens the pumps. A balance. |
| Water chemistry | Facility/cooling-tower water can be corrosive or scaling; this drives plate material (316 vs titanium) and gasket choice. |
| Redundancy & maintenance | Gasketed plate units can be opened, cleaned, and re-plated; plan for N+1 where uptime demands it. |
Five things to have ready before you specify
- Heat load and the two loop temperatures. Entering and leaving temps on both the technical and facility sides.
- Flow rates and allowable pressure drop on each side.
- Water chemistry on the facility side. Cooling-tower water especially — this picks the plate and gasket materials.
- Is this isolating a liquid-cooling loop? Direct-to-chip and immersion loops have tighter cleanliness and control requirements.
- Redundancy expectation. N+1 or better changes the count and sizing.
Get help sizing the right heat exchanger
George Grant Company represents Sondex heat exchangers across Tennessee, Georgia, and Alabama, and our team supports sizing, material selection, and configuration. If you are designing or retrofitting data center cooling and want the heat exchangers sized correctly for the load and the water chemistry, reach out and we will help you get it right.