Commercial Chiller Replacement: How to Keep the Cooling Running During the Changeover

Swapping out a commercial or industrial chiller is never simply a case of “old unit out, new unit in.”

First, the existing unit has to come offline. It needs to be isolated and disconnected, and sometimes craned out if it is a large unit. From there, the pipework, electrics and controls often need reworking before the new chiller can go into position, let alone be connected, tested and commissioned.

All of that creates a period when the permanent chilled-water system simply is not available.

Some sites can live with a full cooling shutdown for a few days. Others cannot. Hospitals, manufacturing plants, data centres, commercial buildings and sites handling temperature-sensitive products often need cooling to continue throughout the replacement.

That is where a temporary chiller comes in. Install and commission it before the existing system goes offline, and it can carry the full load or protect the critical areas until the permanent unit takes over.

Aircon Rentals supports these projects with temporary chillers, pumps, hoses, electrical equipment and temporary power. The permanent replacement itself is usually handled by the site’s mechanical contractor, the manufacturer, a consultant or the in-house facilities team.

What Actually Happens During a Commercial Chiller Replacement?

The scope changes depending on the existing system, the new equipment and the building or process behind it. A planned replacement typically covers:

1. Assessing the condition of the existing chiller
2. Confirming current and future cooling requirements
3. Selecting and procuring the permanent replacement
4. Planning access, lifting and equipment positioning
5. Preparing hydraulic and electrical connections
6. Isolating and removing the existing equipment
7. Completing pipework, electrical and control modifications
8. Installing the new chiller
9. Testing and commissioning the permanent system
10. Handing the cooling load back to the new equipment

Cooling towers, pumps, heat exchangers, air handling units, building management systems and switchboards can all come into it. Treat the job as a complete cooling-system project, not an equipment swap.

For a rundown of the main rental options, see our guide to different chiller configurations for hire.

When Does a Chiller Actually Need Replacing?

Age is not the deciding factor on its own. Condition matters more, and so does whether the chiller can still keep up with what the building or process needs from it now.

A few things tend to force the question. Breakdowns keep coming back. Repair bills climb each time. Capacity has dropped. A compressor or heat exchanger is nearing the end of its life. Parts are becoming difficult to source. The load may have changed, part-load control may be poor, energy use may be rising, or a refurbishment may be coming up. Redundancy requirements and refrigerant changes can also move replacement higher up the list.

Repair, refurbish or replace. Whichever way it goes, base the decision on a proper technical and financial assessment.

Once that decision is made, a different question takes over: how do you keep cooling running while the permanent chiller is out of action?

Why Temporary Cooling Needs to Be Planned Early

Bring temporary cooling into the conversation during the initial planning stage, not after the old chiller has already been disconnected.

Early planning gives the project team time to work out which areas or processes must stay running, how much temporary capacity is genuinely needed, where the equipment can sit and how it will connect to the existing chilled-water system.

Pumps might be needed. Spare electrical capacity might not exist. A generator may be required. Hoses and cables need a safe route. The load has to move across to the temporary system and back again without unnecessary disruption. There also needs to be a fallback if the permanent works run late.

It also means temporary connection points can be installed during the preparatory works, allowing the temporary system to be tested before the permanent chiller is isolated.

Build enough time into the programme to test the permanent system properly. Remove the rental equipment the moment the new chiller starts, and there is nothing left to fall back on if commissioning identifies a fault.

Which Facilities Tend to Need Cooling Through a Replacement?

Losing cooling does not affect every site in the same way. The temporary system should protect what actually matters on that site, whether that is safety, production, asset protection or keeping the facility open.

Hospitals and Healthcare Facilities

Operating theatres, patient areas, medical equipment, air handling, humidity control, imaging suites, sterile environments and communications rooms can all depend on chilled water.

At a regional hospital in Northern NSW, the existing 1,200 kW air-cooled chiller required an upgrade. Aircon Rentals supplied a trailer-mounted 1,300 kW unit. The chiller, hoses, cabling, distribution equipment and pump travelled on one trailer, which reduced installation time and removed the need for crane-based positioning. Read the regional hospital chiller upgrade case study.

Commercial Buildings and Hotels

Occupied offices, retail spaces, tenants, communications rooms and essential building services all need cooling to keep functioning normally.

Sometimes the facility team maintains the whole building. Sometimes it reduces the scope to occupied and critical areas. Either way, planning needs to account for tenant hours, after-hours shutdown windows, loading-dock access, public areas, noise limits, plant-room location, fire exits, pedestrian routes and server rooms.

A Brisbane commercial-building project shows how temporary cooling can support occupied areas during wider works. Read the case study on additional cooling during a building refurbishment.

Manufacturing and Industrial Facilities

Machinery, production lines, process fluids, product quality and working conditions can all depend on industrial cooling. Losing cooling can stop production even while the rest of the site remains operational.

Temporary capacity is often designed around a specific machine or production stage rather than the building’s full installed load.

Aircon Rentals supplied temporary cooling to a Melbourne dairy manufacturer where limited space and available power shaped the system design. Read the industrial chiller hire dairy manufacturing case study.

Food and Beverage Production

Ingredient and product cooling, fermentation, process-water temperature control, packaging equipment, cold storage and temperature-sensitive processing can all rely on chilled water. Cooling demand may also shift with the production schedule and the season.

At a Victorian winery, Aircon Rentals supplied 500 kW of low-temperature cooling at a leaving water temperature of minus 6°C during crush season. The package included a buffer tank, pumps, hoses and electrical cables and ran for 12 weeks. Read the winery additional cooling capacity case study.

That project involved additional capacity rather than a chiller replacement, but the same principle applies: size the temporary system around the real process conditions, not a guess.

Universities and Institutional Facilities

Large institutional sites often run a central energy plant that feeds several buildings or precincts at once. Temporary cooling may need to protect research equipment, laboratories, teaching buildings, data rooms, libraries, student accommodation and occupied administration buildings.

At a Queensland university, the central plant supplied roughly 5,000 kW across two precincts. When one chiller failed, Aircon Rentals supplied 1,000 kW of supplemental capacity using multiple 200 kW units selected around the site’s space and noise restrictions. Read the university energy plant temporary cooling case study.

Data Centres and Technology Environments

These environments have almost no tolerance for a cooling gap. The temporary system may need redundant capacity, round-the-clock operation, generators, remote monitoring, staged commissioning and a backup plan if the permanent project slips.

Where chilled water cannot be maintained across the full facility, temporary air handling units or direct cooling for specific rooms may be the better answer.

Aquatic and Leisure Facilities

Pool-water temperature, space conditions and humidity all need to be considered. Aquatic centres may depend on chillers or heat-pump chillers to keep those conditions stable, and pool temperatures do not recover the moment cooling is restored.

Plan for the recovery time, not only the shutdown itself. See how an 80 kW heat-pump chiller supported an aquatic centre during a longer-term temporary requirement.

For more examples across different sectors, see our article on air-cooled chiller applications by industry.

How Does Temporary Cooling Actually Work During a Replacement?

The temporary system is normally installed and commissioned before the existing chiller goes offline.

What ends up on site depends on the job. Sometimes it is one chiller. Sometimes it is several. The system may also include chilled-water pumps, flexible hoses, Victaulic pipework, isolation valves, heat exchangers, buffer tanks, electrical cables, distribution boards, a generator, air handling units, fan coil units and monitoring equipment.

The temporary chiller connects to suitable points on the existing chilled-water circuit. Flow, temperatures, pressures and controls are tested. Once that is complete, the cooling load shifts across to the rental system and the permanent contractor can isolate, remove and replace the existing unit.

After the new chiller has been tested and commissioned, the load moves back. The temporary system stays in place through the changeover until the new equipment has proven itself.

Aircon Rentals supplies temporary chiller hire across air-cooled, water-cooled, heat-pump and low-temperature units from 10 kW to 2,000 kW.

Temporary Cooling on Real Repair and Replacement Projects

Planned Repair of a 1,400 kW Water-Cooled Chiller

A 1,400 kW water-cooled chiller at the Royal Melbourne Hospital Parkville site had developed operational problems. Repairing it properly meant putting a temporary system in place first.

Aircon Rentals supplied two air-cooled chillers, rated at 430 kW and 520 kW, supported by two variable-speed chilled-water pumps. The installation also required 120 metres of flexible chilled-water lines, 160 metres of electrical cable and switchboards for the chillers and pumps.

Traffic management, temporary fencing and six crane-truck deliveries were required to complete the installation and removal with minimal disruption to hospital operations. Read the full case study on temporary chillers during planned capital equipment repair works.

Permanent Chiller Delayed at New Operating Theatres

A Brisbane hospital was facing a delayed opening for its new operating theatres because the permanent chiller plant had not arrived.

Aircon Rentals arranged a 200 kW air-cooled heat-pump chiller with a chilled-water bypass, 120 metres of chilled-water lines, 160 metres of temporary electrical cables, remote monitoring, security barriers and noise-control measures. The temporary system was arranged within 12 hours and initially operated for four weeks.

When the permanent plant arrived, the load transferred across in stages so the new equipment could be checked before the temporary chiller was removed. Read the case study on temporary cooling while permanent chiller equipment was delayed.

Regional Hospital Chiller Upgrade

At a regional NSW hospital, the 1,200 kW air-cooled chiller required an upgrade. Aircon Rentals supplied a 1,300 kW temporary chiller mounted on a purpose-built trailer.

The hoses, electrical cabling, distribution equipment and chilled-water pump travelled with the chiller. One load simplified delivery, positioning and removal and avoided separate crane and rigging costs. Read the regional hospital chiller upgrade case study.

Controlled Transfer to a Permanent Replacement

After a failure at a Brisbane hospital, Aircon Rentals installed a 200 kW temporary heat-pump chiller at ground level, supported by a circulation pump and 80 metres of Victaulic pipework and flexible hoses.

It operated for 12 weeks. When the new permanent chiller was ready, the load returned in controlled stages before the rental equipment was decommissioned. Read the 200 kW temporary hospital chiller case study.

How Much Temporary Capacity Do You Actually Need?

The temporary chiller does not always need to match the nameplate rating of the unit being removed.

Permanent chillers are often sized for peak design conditions, future expansion or redundancy. The actual load during a replacement window may be much lower.

Base the temporary requirement on the actual operating load, including:

• Critical and non-critical areas
• Required leaving and entering water temperatures
• Water flow rate
• Ambient conditions
• Fluid type and glycol concentration
• Operating hours
• Production or occupancy schedules
• Other chillers remaining in operation
• Required redundancy
• Expected project duration

Aircon Rentals sizes temporary chillers using water temperatures, ambient conditions, fluid type and flow rate.

Full-Load Temporary Cooling

The rental system carries the full required load. This suits hospitals, continuous manufacturing facilities and occupied buildings that cannot reduce operations during the replacement.

Critical-Load Temporary Cooling

The temporary system protects only the areas, processes or equipment that must remain operational. In an office building, that may mean server rooms and occupied floors. In a factory, it may be one production line that cannot stop.

Modular or Staged Temporary Cooling

Several smaller chillers replace one large unit. This can suit sites with tight access, limited power, changing requirements, separate chilled-water circuits or limited space for one large machine.

Air-Cooled or Water-Cooled Temporary Chiller?

The rental configuration should follow the temporary installation rather than simply mirror the permanent chiller.

Air-Cooled Temporary Chillers

Air-cooled units reject heat directly into the surrounding air. They do not need a separate condenser-water circuit or cooling tower.

They may suit sites where:

• Outdoor equipment space is available
• Installation speed matters
• Cooling-tower infrastructure is unavailable
• Existing condenser-water equipment is part of the replacement scope
• A self-contained setup is easier to deliver

View the available air-cooled chiller fleet or read the air-cooled chiller hire planning guide.

Water-Cooled Temporary Chillers

Water-cooled units reject heat through a condenser-water circuit. They can be a strong option where existing cooling towers and condenser-water connections remain available.

They may suit sites where:

• Large cooling capacity is required
• Existing cooling towers can remain operational
• Suitable condenser-water connections already exist
• Available electrical capacity favours a water-cooled setup
• Space or noise restrictions make an air-cooled system less practical

View the water-cooled chiller fleet or read our guide to renting water-cooled chillers. The current water-cooled range runs from 200 kW to 2,000 kW.

The temporary system does not have to use the same heat-rejection method as the permanent equipment. Access, power, condenser water, project duration and available space should determine the setup.

Site Access and Equipment Positioning

A technically suitable chiller cannot support the project if it cannot be delivered, positioned or connected safely.

The site assessment should consider:

• Equipment dimensions and weight
• Delivery vehicle access
• Crane or rigging requirements
• Ground loading
• Rooftop, basement or loading-dock access
• Air circulation around air-cooled equipment
• Distance to the connection points
• Hose and cable routes
• Pedestrian and vehicle movement
• Fire exits
• Public access
• Noise restrictions
• Security
• Drainage
• Equipment removal at the end of the project

Sites with narrow laneways, basements, rooftops, loading docks or limited plant space may need several smaller units or a different equipment configuration.

For more detail, read our guide to chiller hire for tight-access sites.

Hydraulic Connections, Pumps and Hoses

A complete temporary cooling system often requires more than the rental chiller.

The project may also need:

• Primary or secondary chilled-water pumps
• Flexible hoses or temporary rigid pipework
• Adaptors and fittings
• Isolation valves
• Pipe insulation
• Strainers
• Buffer tanks
• Heat exchangers
• Flow meters
• Temperature and pressure monitoring

Pipe diameter alone does not confirm that a connection point can provide the required flow. The assessment should also consider available pressure, system resistance, hose length, elevation, fluid type and the operating characteristics of the existing pumps.

Aircon Rentals supplies water pump hire for temporary chiller and process-cooling systems.

Electrical Capacity and Temporary Power

Commercial chillers can create a substantial electrical load.

Before the equipment is selected, confirm:

• Supply voltage and phase
• Available switchboard capacity
• Running current
• Starting current
• Connection method
• Cable length
• Cable route
• Protection requirements
• Pump and accessory loads
• Existing site loads
• Electrical isolation requirements

Where the site cannot provide enough spare electrical capacity, the temporary system may need generator hire and temporary electrical distribution.

Power needs to be assessed before the temporary chiller is confirmed. A unit may satisfy the cooling requirement but still be unsuitable if the site cannot power it.

Typical Temporary Chiller Implementation Process

Project Review

Review the replacement programme, the permanent works and the level of cooling continuity the site needs.

Load Assessment

Identify the full cooling requirement and the areas, processes or equipment that must remain operational.

Site Inspection

Assess access, equipment position, hydraulic connections, power supply, noise, security and temporary hose and cable routes.

Temporary System Design

Select the chillers, pumps, hoses, power equipment, controls and backup arrangements. Complex projects may require formal temporary HVAC design and engineering.

Site Preparation

Prepare the equipment area, pipe connections, electrical supply and temporary routes before delivery.

Delivery and Positioning

Deliver and place the temporary equipment using the agreed vehicle, crane or rigging method.

Hydraulic and Electrical Installation

Connect the chiller, pumps, hoses, cables, switchboards and supporting equipment.

Testing and Commissioning

Check flow, temperatures, pressures, controls, alarms and equipment operation before the permanent chiller is isolated.

Temporary Operation

The rental system carries the agreed cooling load while the permanent equipment is removed and replaced. Longer projects may use remote equipment monitoring to track operation and identify changes during the rental period.

Transfer to the Permanent Chiller

Once the new chiller has passed testing and commissioning, transfer the load back. A staged transfer allows the team to confirm flow, temperatures, controls and system stability before the temporary equipment is switched off.

Decommissioning and Removal

Remove the temporary chillers, pumps, hoses, cables, barriers and supporting equipment after the permanent system is operating reliably.

Planned Chiller Replacement Versus an Unexpected Breakdown

A planned replacement gives the team time to assess the load, prepare the site and test the temporary system before the existing equipment is shut down.

An unexpected breakdown requires a different response. The immediate priority is restoring critical cooling using the equipment, access, connections and power that are available.

Planned replacement	Unexpected breakdown
Known project programme	Immediate operational disruption
Load can be assessed in advance	Critical loads must be identified quickly
Connections can be prepared	Temporary connections may need to be adapted
Power can be arranged before delivery	Available power may limit equipment selection
Temporary cooling can be commissioned before shutdown	Rapid mobilisation may be required
Changeover can be scheduled	Restoration takes priority
Contingency can be built into the project	Available equipment may shape the solution

For an unplanned failure, read our guide to emergency chiller breakdown hire.

Facilities with critical cooling requirements should also consider creating a temporary cooling contingency plan before a failure or major replacement project begins.

What Affects the Cost of Temporary Cooling?

The cost depends on the full system and installation scope, not only the chiller capacity.

Factors can include:

• Required cooling capacity
• Chiller type
• Number of units
• Rental duration
• Pumps
• Hoses and temporary pipework
• Electrical cables and distribution
• Temporary generators
• Delivery distance
• Cranes or rigging
• Restricted access
• Installation labour
• After-hours work
• Monitoring
• Noise-control measures
• Required redundancy
• Removal and site restoration

A smaller critical-load system may cost less than maintaining the facility’s full installed load. Reducing capacity without a proper load assessment, however, can leave essential operations unprotected.

For a detailed pricing breakdown, read our guide to commercial chiller hire costs.

Commercial Chiller Replacement Planning Checklist

Before the existing chiller is taken offline, confirm:

• Required temporary cooling capacity
• Critical areas and processes
• Required water temperatures
• Water flow rate
• Fluid type and glycol concentration
• Operating hours
• Replacement project duration
• Temporary chiller configuration
• Equipment position
• Delivery access
• Crane or rigging requirements
• Hydraulic connection points
• Pump requirements
• Hose sizes and routes
• Electrical capacity
• Generator requirements
• Cable routes
• Noise restrictions
• Site security
• Testing and commissioning procedure
• Remote monitoring requirements
• Backup and redundancy requirements
• Permanent-system commissioning programme
• Load-transfer procedure
• Temporary equipment removal plan
• Contingency for project delays

Where uninterrupted cooling is required, the temporary system should be installed, tested and commissioned before the existing chiller is isolated.

Temporary Cooling Support During Commercial Chiller Replacement

Aircon Rentals supplies temporary chillers and associated equipment for planned replacements, repairs, upgrades and extended commissioning periods across Australia.

The team can assist with:

• Cooling-load assessment
• Equipment selection
• Temporary pumps and hoses
• Heat exchangers and buffer tanks
• Electrical and generator requirements
• Delivery and equipment positioning
• Installation and commissioning
• Short-term and extended rental periods
• Remote monitoring
• Controlled decommissioning and removal

Planning a Commercial Chiller Replacement?

Discuss the replacement programme early so the temporary system can be assessed, prepared and commissioned before the existing chiller is taken offline.

Discuss Your Temporary Cooling Requirements

View Our Temporary Chiller Range

Frequently Asked Questions

Can a Facility Remain Operational During a Chiller Replacement?

A facility may be able to remain operational if a suitable temporary cooling system is installed and commissioned before the permanent chiller is shut down. The system can support the full required load or selected critical areas and processes.

Does the Temporary Chiller Need to Match the Existing Chiller Capacity?

Not always. Temporary capacity should be based on the actual load that must be maintained during the replacement, along with water temperatures, flow rate, operating conditions and redundancy requirements.

Can a Temporary Chiller Connect to Existing Pipework?

In many projects, a temporary system can connect to suitable points in the existing chilled-water circuit. The connection location, diameter, condition, pressure and available flow must be assessed before installation.

Can an Air-Cooled Temporary Chiller Replace a Water-Cooled Chiller?

Potentially. The temporary system does not always need to use the same heat-rejection method as the permanent chiller. Available space, power, condenser water, site access and required capacity will determine the most practical option.

Can a Generator Power a Temporary Commercial Chiller?

Yes. A temporary generator can be supplied where the site does not have enough spare electrical capacity. Generator sizing must include the chiller, pumps and all supporting electrical equipment.

Should Temporary Cooling Be Installed Before the Existing Chiller Is Removed?

Where continuous cooling is required, the temporary system should be installed, commissioned and tested before the existing chiller is isolated.

Can Temporary Cooling Support Only Part of a Building?

Yes. The system can be sized around essential floors, rooms, processes or equipment where the existing hydraulic system allows those loads to be separated.

How Long Can a Temporary Chiller Remain Installed?

A temporary chiller can support a brief shutdown or remain operational during an extended replacement project. The rental period should include time for permanent-system testing, possible delays and a controlled transfer to the new equipment.

What Happens When the New Permanent Chiller Starts?

The cooling load can be transferred from the rental system to the permanent chiller in stages. This allows temperatures, water flow, controls and operation to be checked before the temporary equipment is decommissioned.

What Happens if the Permanent Chiller Delivery Is Delayed?

The temporary system can remain in operation subject to equipment availability, the rental arrangement and the site’s operating requirements. Build enough flexibility into the rental period where delivery or commissioning dates may change.