Buy a used data center chiller against the cooling duty it must deliver at the receiving site's actual temperatures, fluid conditions and electrical supply. Confirm equipment identity, selected capacity, heat-rejection requirements, refrigerant, service history and restart behavior. A nominal tonnage or previous installation's performance does not establish suitability for your GPU deployment.
A chiller can be available for purchase while the cooling plant needed to use it remains incomplete. Pumps, heat-rejection equipment, controls, electrical infrastructure and commissioning all affect when the facility can accept computing load. Define that complete operating boundary before comparing an equipment-only offer with a broader installed scope.
Use SecondWatt's chiller catalogue for equipment-family research. The purchase decision should then follow the identified unit's selection report, condition evidence and receiving-site integration plan.
Key Takeaways
- State cooling duty and fluid temperatures at the actual chiller boundary.
- Keep evaporator capacity, electrical input and condenser heat rejection separate.
- Compare air-cooled and water-cooled offers with their required supporting plant.
- Verify refrigerant, condition, controls and support for the identified used unit.
- Agree restart, site acceptance and delivered scope before committing to a schedule.
Define the cooling duty and the facility interfaces#
Start with the load that reaches the cooling plant. Identify the deployment phases, expected heat load and the equipment included in that boundary. GPU nameplate power is useful input, but a complete facility assessment must account for where heat is collected and how it reaches the chiller.
Separate the technology cooling loop from the facility water system. A coolant distribution unit may provide an interface between them, but its presence does not identify the required chiller temperature or establish the complete heat-rejection design. The liquid-cooling equipment catalogue provides adjacent system context.
Cooling requirement for a sourcing enquiry#
| Field | Information to provide |
|---|---|
| Cooling duty | Required kW or MW of cooling at the named boundary |
| Fluid | Water or identified mixture, with concentration where applicable |
| Temperatures | Entering and leaving fluid requirements |
| Flow | Required range and allowable pressure drop |
| Site conditions | Relevant outdoor and plant operating conditions |
| Operating profile | Load range, deployment phases and annual duty |
| Continuity | Required maintenance and equipment-outage cases |
| Interfaces | Pumps, controls, electrical supply and heat rejection |
Have the design team determine whether mechanical chilling is required for every operating condition. Some liquid-cooling arrangements can use other heat-rejection approaches for part or all of their duty, depending on the permitted temperatures and climate. Do not assume either that liquid cooling eliminates chillers or that every GPU deployment needs the same chilled-water temperature.
Place accepted cooling operation on the same project schedule as computing and electrical readiness. The data center power procurement roadmap provides that coordination context. Chiller shipment is an intermediate milestone; the usable cooling plant is the deployment dependency.
Keep cooling capacity, electrical input and rejected heat distinct#
A chiller's cooling capacity describes heat removed at its cooling boundary. Its electrical input is a separate quantity. The condenser must reject the removed heat plus the relevant equipment energy that enters the refrigerant circuit. These quantities should not be given the same MW label without explanation.
Consider a hypothetical steady operating point with 1,800 kW of evaporator cooling and 300 kW of compressor electrical input. Assume all of that input becomes condenser heat and neglect other losses for this illustration. The condenser duty is then 1,800 + 300 = 2,100 kW. Separately supplied plant loads are outside this example.
Illustrative energy and flow calculation#
| Quantity | Calculation | Result |
|---|---|---|
| Evaporator cooling | Given example duty | 1,800 kW |
| Compressor input | Given example input | 300 kW |
| Condenser heat rejection | 1,800 + 300 | 2,100 kW |
| Cooling COP at this boundary | 1,800 ÷ 300 | 6.0 |
| Water mass flow at a 6 K rise | 1,800 ÷ (4.18 × 6) | About 71.8 kg/s |
The flow calculation uses an illustrative water specific heat of 4.18 kJ/kg·K. Use the actual fluid properties at the relevant operating temperature for a project calculation. A glycol mixture needs its own properties and equipment selection; replacing water without revisiting the thermal and hydraulic calculation can invalidate the comparison.
The COP example covers the defined chiller boundary. It is not a whole-plant efficiency value once separately supplied pumps, fans or other equipment are added. Compare offers using the same accounting boundary and identify which auxiliary loads are already included so they are not counted twice.
Ask the respondent to return cooling capacity, input power and heat rejection as separate fields at each agreed condition. This makes an apparent capacity match reviewable and exposes whether a proposed supporting plant has been sized against the correct thermal duty.
Compare air-cooled and water-cooled equipment as complete systems#
An air-cooled chiller rejects condenser heat to outdoor air. A water-cooled chiller transfers that heat to a condenser-water circuit that needs its own heat-rejection arrangement. The equipment comparison therefore extends beyond the chiller enclosure to the required site infrastructure.
The named product references below illustrate different architectures and published family ranges. They are not equivalent selections or evidence that units are currently offered on the secondary market.
Two OEM reference ranges, with their regional scope retained#
| Reference | Published configuration and range | Purchase qualification |
|---|---|---|
| YORK YVAM, AP-region product page | Air-cooled magnetic-bearing centrifugal; 250–475 TR, 880–1,670 kW | Match the actual regional version and selected duty |
| Carrier AquaEdge 19MV, US product page | Water-cooled centrifugal; 150–700 tons, 527–2,461 kW | Confirm the offered configuration and receiving-site selection |
These are the ranges printed on the identified pages. They should not be extended to every regional offering or older revision. A nominal capacity within either range still needs a selection at the buyer's required fluid and ambient or condenser-water conditions.
For air-cooled candidates, review layout, airflow, recirculation, access and sound requirements. For water-cooled candidates, identify condenser-water pumps, piping, controls and the heat-rejection equipment included in the design. Record any water-supply, treatment and operating responsibilities that belong outside the chiller purchase.
Plant scope to reconcile between offers#
| Scope item | Question for the respondent |
|---|---|
| Heat rejection | What equipment and design duty are included? |
| Pumping | Which pumps, drives and hydraulic responsibilities are included? |
| Electrical | Which starters, drives, disconnects and connection work are included? |
| Controls | What plant coordination and monitoring functions are supplied? |
| Site work | Who provides supports, access, piping and installation? |
| Commissioning | Who demonstrates operation of the assembled system? |
SecondWatt's YVAM dossier and AquaEdge 19MV dossier support family discovery. Require a dated selection and equipment-specific offer to establish the actual transaction scope.
Request performance at the site's operating conditions#
Ask for a performance matrix covering design duty, relevant part loads and the conditions that challenge the receiving installation. Include entering and leaving fluid temperatures, flow, fluid composition, pressure drop and the applicable heat-rejection conditions. Request cooling output and electrical input together.
The Department of Energy's electric-chiller purchasing guidance distinguishes full-load and part-load efficiency in its federal procurement framework. A standardized part-load metric is useful comparison information, but it is not a prediction of one data center's annual energy use. The page's federal purchasing requirements should not be presented as universal used-equipment rules.
Conditions to include in the selection response#
| Operating case | Evidence required |
|---|---|
| Design cooling load | Capacity and input at the specified site conditions |
| Part load | Available operating range and input at relevant load levels |
| Outdoor extremes | Performance and limits at the stated environmental conditions |
| Fluid variation | Selection for the actual fluid and temperature requirements |
| Maintenance case | Remaining plant capability with the defined equipment unavailable |
| Expansion phase | Fit with both initial and later operating duty |
Check the electrical interface alongside the thermal selection. Confirm voltage, frequency, maximum input, starting or recovery behavior, and any power-quality information needed by the electrical designer. A drive-equipped unit still needs an actual compatibility assessment with its proposed source.
The data center transformer sizing guide is relevant to the facility supply serving that demand. Do not use the chiller's thermal MW rating as its electrical load or copy a model-family current into a project without checking the selected version.
Keep source evidence and assumptions visible. Label whether a value comes from an original factory selection, a new manufacturer selection, operating records or an engineering estimate. An old report may be useful, but its conditions must be reconciled before it can support performance at another site.
Investigate condition, refrigerant and serviceability#
Request the serial number, model code, nameplates, original configuration and service records before treating a used chiller as a viable candidate. Reconcile compressor hours, starts, major repairs and replacement components with the equipment being sold. Document shutdown, removal and storage conditions where known.
Set the inspection scope for the actual construction. Air-cooled equipment needs the relevant coil, fin, fan and structural condition assessment. Water-cooled equipment needs the applicable evaporator and condenser condition evidence. Oil analysis is relevant only where the design uses an oil system; a generic checklist should not assume every compressor has one.
Used-chiller evidence file#
| Area | Evidence to request |
|---|---|
| Identity | Serial number, model code, nameplates and configuration records |
| Operation | Hours, starts, alarms, trips and available performance trends |
| Major equipment | Compressor, heat-exchanger, fan and drive service history as applicable |
| Refrigerant | Actual type, charge status, service and leak-related records |
| Controls | Controller version, configuration access and monitoring interfaces |
| Preservation | Shutdown, storage, removal and shipping protection records |
| Support | Parts, specialist service and recommissioning path |
Confirm the refrigerant actually installed. A product family that lists several refrigerant options does not establish that an existing unit can be converted between them without manufacturer-approved work. Include the refrigerant's availability and the required service arrangements in the receiving-site assessment.
For US work, the EPA's Section 608 technician-certification requirements address certification for covered activities involving equipment that could release refrigerant. Assign that work to appropriately qualified service providers and confirm the rules applicable to the actual equipment and destination. This is not a determination that a particular used chiller is prohibited from sale or relocation.
Ask which defects are corrected before shipment and which remain with the buyer. A workshop inspection, a powered control display and an operating test establish different things. Retain the report scope and limitations instead of describing every inspected unit as fully proven under load.
Verify restart and acceptance with the supporting plant#
Cooling continuity involves more than the time until a compressor can restart. The system also needs water circulation, available heat rejection, controls and a suitable electrical source. Establish when useful cooling returns at the agreed temperature and load after the specified disturbance.
Trane's CenTraVac data center chiller page includes restart and capacity-recovery features in its product description. Treat such features as configuration-specific starting points for questions. Obtain the applicable conditions and evidence for the offered unit rather than transferring a family claim to every used chiller.
Define the role of any thermal reserve or supporting power equipment in the actual design. The UPS sizing guide helps distinguish electrical load and runtime requirements. It does not establish that an existing UPS can support a chiller's compressor or complete cooling plant.
Acceptance milestones for a relocated chiller#
| Milestone | Evidence to agree |
|---|---|
| Before purchase | Identified configuration, condition and outstanding work |
| Before shipment | Completed preparation, documentation and agreed checks |
| On receipt | Condition inspection and supplied-equipment reconciliation |
| Before operation | Completed site installation and commissioning prerequisites |
| Performance acceptance | Results at the agreed load, temperatures, flow and power boundary |
| Disturbance recovery | Demonstrated response for the specified operating case |
Use qualified technical parties to develop and conduct the detailed test plan. Set acceptance criteria, responsibilities and the treatment of exceptions before commitment. If the available test arrangement cannot reproduce the receiving site's design condition, identify the limitation and the later verification required.
Preserve the accepted settings, drawings and performance record at handover. State who supports subsequent controls changes and which modifications require renewed review. The purchasing file should explain what was demonstrated on the delivered equipment and what depends on later site work.
Request a complete used-chiller offer#
Send the cooling duty, fluid and temperature requirements, site conditions, electrical supply, operating profile, acceptable condition, destination and required date. Include the heat-rejection and installation scope needed so respondents can distinguish an equipment purchase from a complete plant requirement.
Request an itemized bill of supply and a deviations list. Identify removal, preservation, transport, lifting, refrigerant handling, installation, testing and commissioning responsibilities. Compare dated offers on the same boundary before drawing conclusions from their headline equipment prices.
Where delivery uses a trade term, name the rule and place. The ICC's Incoterms 2020 guidance provides the delivery-responsibility framework. Installed capacity, performance acceptance and ongoing service remain separate obligations that need explicit agreement.
SecondWatt acts as an independent intermediary connecting equipment buyers and sellers. To request used-chiller equipment sourcing, provide cooling capacity, required temperatures, fluid, power supply, preferred configuration, acceptable condition, destination and target date. Attach an existing selection or design brief where available.
FAQ: Buying used chillers for GPU data centers#
Does liquid cooling mean a data center no longer needs chillers?#
It depends on the cooling architecture, permitted temperatures, climate and heat-rejection design. A coolant distribution unit does not determine those requirements by itself. Have the design team establish the facility cooling conditions and whether mechanical chilling is needed throughout the operating year or only for particular conditions.
Is a chiller's cooling MW rating its electrical demand?#
No. Cooling capacity is the thermal duty removed at the stated boundary. Electrical input is a separate quantity, and condenser heat rejection includes the removed heat plus the relevant equipment input. Request all three fields at the same operating conditions and keep separately supplied plant loads visible.
Can I size a chiller using nominal tonnage alone?#
Nominal tonnage is a starting point for identifying equipment families. Require a selection for the actual temperatures, fluid, flow and heat-rejection conditions. Check the applicable operating range and available capacity during required maintenance cases. A unit's earlier selection may not describe its performance at the receiving site.
Are the refrigerant options listed for a model interchangeable?#
Do not assume they are. Identify the refrigerant and configuration in the offered unit and request manufacturer confirmation of any proposed change. Different listed product options do not establish an approved conversion for an existing machine. Include the necessary technical work, service support and destination requirements in the assessment.
What evidence matters most when buying a used chiller?#
Start with identity, configuration, maintenance and operating records, then obtain a condition assessment appropriate to the equipment. Reconcile the selected duty with the receiving site. Confirm refrigerant status, controls access, included components and the recommissioning path. Agree what the acceptance evidence will demonstrate and how outstanding deficiencies will be resolved.
Does a fast compressor restart prove cooling continuity?#
No. Useful cooling recovery also depends on circulation, heat rejection, controls, power availability and the load's permitted temperature excursion. Define the complete disturbance case and the required recovery outcome. Verify the supplied configuration within the supporting plant rather than relying only on a compressor restart figure.