How to Select a Heat Exchanger for Industrial Refrigeration Systems: A Practical Engineering Guide

Selecting a heat exchanger for an industrial refrigeration system requires more than comparing heat exchanger types or nominal cooling capacities.

The right solution depends on the heat exchanger duty, refrigerant, cooling or heat-rejection capacity, inlet and outlet temperatures, design pressure, allowable pressure drop, secondary fluid, fouling risk, ambient conditions, installation space and maintenance strategy.

Plate heat exchangers are compact and provide high heat-transfer performance. Shell-and-tube heat exchangers are robust and can offer good serviceability for many industrial duties. Finned-tube coils are widely used where heat must be transferred between refrigerant or secondary fluid and air, while microchannel heat exchangers can provide a compact, low-internal-volume solution for suitable air-side applications.

The most important rule is simple:

Do not choose the heat exchanger type first. Define what the heat exchanger must do in the refrigeration system first.

This guide explains the selection process step by step for cold storage, food processing, blast freezing, industrial chillers, ice-making systems, process cooling and other industrial refrigeration applications.

Quick Selection Guide: Which Heat Exchanger Should You Choose?

There is no single “best” heat exchanger for every industrial refrigeration system.

A better question is:

Which heat exchanger configuration best matches the required refrigeration duty and operating conditions?

Selection by Refrigeration Duty

Evaporator

An evaporator absorbs heat from a refrigerated space, process stream, water, brine, glycol or another secondary fluid.

Common options include:

• Finned-tube air coolers

• Brazed plate heat exchangers

• Gasketed or semi-welded plate heat exchangers

• Shell-and-tube evaporators

• Plate-fin heat exchangers for specialized applications

The final choice depends heavily on whether the evaporator operates as a direct-expansion, flooded, thermosyphon or pumped/overfeed system.

Danfoss identifies DX, thermosyphon and pump-circulated evaporators as different configurations within industrial refrigeration systems, with different refrigerant circulation and control characteristics.

Condenser or CO₂ Gas Cooler

A condenser rejects heat from the refrigerant and changes refrigerant vapor into liquid when the system operates below the refrigerant's critical point.

Typical designs include:

• Air-cooled finned-tube condensers

• Microchannel condensers

• Shell-and-tube water-cooled condensers

• Plate heat exchangers

• Evaporative condensers

A transcritical CO₂ system is different. Above the critical point, CO₂ does not undergo conventional condensation on the high side. Heat is rejected through a gas cooler, so its design and high-pressure requirements must be considered separately.

Oil Cooler, Subcooler and Heat Recovery Exchanger

Industrial refrigeration systems can also contain secondary heat exchangers for:

• Compressor oil cooling

• Refrigerant subcooling

• Desuperheating

• Economizer duties

• Cascade systems

• Heat recovery

• Process-water heating

These components may have operating conditions very different from the system's main evaporator or condenser.

Quick Comparison of Common Heat Exchanger Types

This table is a starting point rather than a final selection rule. Actual suitability must be checked against the refrigerant, pressure, temperature, material compatibility and required codes.

Step 1: Define the Heat Exchanger’s Function in the Refrigeration System

One of the most common selection mistakes is starting with statements such as:

“We need a plate heat exchanger.”

or:

“We need a shell-and-tube heat exchanger.”

That starts the selection process in the wrong place.

First determine what thermal duty must be performed.

Evaporators: Absorbing Heat from the Process or Cold Space

An evaporator absorbs heat while refrigerant evaporates at a controlled pressure and temperature.

However, the physical form of the evaporator changes according to what needs to be cooled.

Air Coolers for Cold Rooms and Freezing Applications

Cold rooms, refrigerated warehouses and freezing tunnels typically require an air-side evaporator.

A finned-tube air cooler may include:

• Tube-and-fin coil

• Fans

• Drain pan

• Casing

• Defrost system

• Refrigerant distributor or circuiting arrangement

Selection is influenced by more than nominal capacity. Engineers should consider:

• Room temperature

• Evaporating temperature

• Temperature difference

• Air volume

• Product load

• Moisture load

• Frost formation

• Fin spacing

• Defrost method

• Fan power

• Required air throw

A freezing application with heavy frost formation, for example, should not automatically use the same fin geometry as a higher-temperature cold room.

Liquid Chillers for Water, Brine and Glycol

When the process requires chilled water, glycol or another secondary fluid rather than direct air cooling, plate or shell-and-tube heat exchangers can become more appropriate.

Key questions include:

• What secondary fluid is used?

• What is its concentration?

• What are the inlet and outlet temperatures?

• What is the flow rate?

• Is freezing possible?

• Is the fluid clean?

• What pressure drop is available?

Fluid concentration is especially important because glycol concentration affects viscosity, pumping requirements and heat-transfer performance.

Condensers: Rejecting Heat from the Refrigerant

A condenser transfers heat from high-pressure refrigerant to air or water.

Air-Cooled Condensers

Air-cooled condensers commonly use finned-tube or suitable microchannel construction.

Important inputs include:

• Condensing duty

• Refrigerant

• Condensing temperature

• Design ambient temperature

• Airflow

• Fan arrangement

• Site altitude

• Noise restrictions

• Coil fouling conditions

• Corrosion exposure

In hot climates, selecting from a mild-weather design condition can result in insufficient heat rejection precisely when maximum refrigeration capacity is needed.

Water-Cooled Condensers

Shell-and-tube and plate heat exchangers can be used for suitable water-cooled condenser applications.

Selection must account for:

• Water inlet/outlet temperatures

• Water quality

• Scaling tendency

• Fouling allowance

• Pressure drop

• Cleaning requirements

• Cooling-tower or process-water conditions

Evaporative Condensers

Evaporative condensers reject heat through a combination of air movement and water evaporation.

Their design considerations include water treatment, scaling, biological control, climate and maintenance requirements. They should therefore be evaluated differently from purely air-cooled condensers.

CO₂ Gas Coolers in Transcritical Refrigeration Systems

CO₂/R744 demands special consideration.

In the supercritical cycle, the high-pressure refrigerant operates above its critical point—eliminating conventional condensation in the high-pressure heat exchanger. Hence, this component is termed a gas cooler.

CO₂ gas cooler design must account for high operating pressure, refrigerant outlet temperature, and variable operating conditions. As Danfoss notes, gas cooler performance and high-pressure control are critical to system capacity and COP in supercritical CO₂ systems.

Accordingly, even with similar cooling capacity requirements, an HFC/HFO condenser cannot be assumed suitable for CO₂.

Secondary Duties: Subcooling, Oil Cooling and Heat Recovery

Industrial systems may contain several additional heat exchangers.

Danfoss' industrial refrigeration handbook identifies duties including evaporators, oil coolers, desuperheaters, condensers, subcoolers and economizers within refrigeration-system arrangements.

Heat recovery is also increasingly relevant. Heat rejected by a refrigeration system may sometimes be recovered for:

• Process hot water

• Cleaning water

• Space heating

• Preheating

• Other plant thermal loads

The required temperature level should be defined before selecting the heat recovery exchanger.

Step 2: Calculate the Required Cooling or Heat-Rejection Duty

Once the duty is defined, determine how much heat must be transferred.

Basic Heat-Load Calculation

For a single-phase secondary fluid such as water or glycol, a simplified sensible heat calculation is:

Q = ṁ × Cp × ΔT

Where:

• Q = heat-transfer rate

• ṁ = mass flow rate

• Cp = specific heat capacity

• ΔT = temperature change

The actual engineering calculation must use fluid properties appropriate to the operating temperature and concentration.

Refrigerant-Side Calculation Using Enthalpy Difference

For refrigerants undergoing evaporation, condensation or gas cooling, calculations normally rely on refrigerant thermodynamic properties.

A simplified energy balance is:

Q = ṁ × (h₂ − h₁)

where h represents specific enthalpy at the relevant inlet and outlet states.

For accurate equipment selection, refrigerant condition cannot be described only by a fluid name such as “R717” or “R744.”

Pressure, temperature, vapor quality, superheat or other state information may also be required.

Why Peak Load and Part-Load Conditions Both Matter

Industrial refrigeration systems rarely operate at one constant condition.

Loads change because of:

• Product throughput

• Door opening

• Outdoor temperature

• Production schedules

• Pull-down periods

• Seasonal variation

• Defrost cycles

A unit selected only at one nominal rating point may operate poorly when the plant load falls or ambient conditions change.

Part-load operation should therefore be considered together with peak load.

Add Design Margin Without Oversizing the Heat Exchanger

A safety margin may be appropriate where uncertainty exists, but there is no universal percentage that should automatically be added to every project.

Excessive oversizing can introduce:

• Poor control

• Unnecessary equipment cost

• Different refrigerant distribution behavior

• Increased physical size

• Unnecessary fan or pump capacity

Design margin should reflect the actual uncertainty in the thermal load, fouling, operating envelope and future expansion requirements.

Step 3: Define the Complete Temperature Program

Cooling capacity alone is insufficient for heat exchanger selection.

Two heat exchangers can both be rated at 300 kW yet require very different surface areas because their temperature conditions differ.

Required Inlet and Outlet Temperatures

Specify the temperatures on both sides wherever possible.

For a liquid cooler, this might include:

• Refrigerant evaporating condition

• Glycol inlet temperature

• Glycol outlet temperature

For a condenser:

• Refrigerant condensing condition

• Air or water inlet temperature

• Required outlet condition

Evaporating and Condensing Temperatures

Evaporation and condensation conditions affect both heat transfer performance and compressor operation.

Lower evaporation temperature increases the available cooling temperature difference but may raise compressor discharge pressure and energy consumption.

Excessively high condensation pressure reduces system efficiency.

Thus, heat exchangers must be selected as integrated components of the refrigeration system—not as standalone units.

Approach Temperature and Temperature Difference

A smaller approach temperature can improve the desired process temperature, but usually requires more effective heat-transfer surface or a different exchanger design.

Instead of asking only:

“What is the capacity?”

ask:

“What capacity must be transferred at what temperature approach?”

That is a much more useful engineering question.

How Ambient Temperature Affects Condenser Selection

For air-cooled cooling, the outdoor design temperature is one of the most crucial input parameters.

Condensers operating in a 25°C environment cannot be selected based on the same assumptions as those operating in a 45°C environment.

High-altitude regions also further alter air density and the performance of fans.

Low-Temperature Operation, Frost Formation and Freeze Protection

At low evaporating temperatures, frost can progressively block airflow through an evaporator coil.

This affects:

• Air pressure drop

• Heat transfer

• Fan performance

• Refrigeration capacity

• Defrost frequency

Secondary-fluid heat exchangers must also be evaluated for freeze risk when the wall temperature can drop below the fluid's freezing point.

Step 4: Match the Heat Exchanger to the Refrigerant

Refrigerant selection changes heat exchanger requirements significantly.

Heat Exchangers for Ammonia Refrigeration Systems

Ammonia, or R717, is widely used in industrial refrigeration, but material compatibility must be treated carefully.

Why Copper and Copper Alloys Require Special Attention with Ammonia

Copper-containing heat exchanger construction should not automatically be specified for ammonia service.

SWEP states that when ammonia is used in its brazed plate heat exchangers, nickel-based brazing must be used instead of conventional copper brazing. It also offers copper-free all-stainless technology for ammonia applications.

Therefore, the statement:

“Brazed plate heat exchangers cannot be used with ammonia”

is too broad.

The correct question is:

Is this specific plate construction, brazing material and pressure rating compatible with the ammonia application?

Shell-and-Tube vs Semi-Welded Plate Designs for NH₃

Shell-and-tube heat exchangers have long been used in industrial ammonia systems and are especially suited for large evaporators and condensers.

Semi-welded plate heat exchangers are another option.

In this design, refrigerant flows through welded channels, while the secondary medium flows through gasketed channels. Alfa Laval offers semi-welded units for evaporators, condensers, superheaters, cascade units, economizers, and condenser cooling.

The appropriate choice depends on:

• Capacity

• Refrigerant charge

• Cleaning requirement

• Pressure

• Fluid cleanliness

• Footprint

• Maintenance strategy

• Project codes

Heat Exchangers for CO₂ Refrigeration Systems

CO₂/R744 presents a different challenge.

High Design Pressure Requirements

The carbon dioxide refrigeration system may withstand higher pressure than many traditional refrigeration systems.

The required design pressure depends on the specific structure of the system and the position of the components.

Do not determine the design pressure of the equipment solely based on the operating pressure.

The applicable regulations, shutdown conditions, safety devices, and the complete pressure range must all be taken into consideration.

Subcritical vs Transcritical CO₂ Applications

In subcritical operation, CO₂ can condense conventionally.

In transcritical operation, the high-side heat rejection occurs in a gas cooler.

Danfoss treats subcritical and transcritical CO₂ system arrangements separately and documents different pressure zones in transcritical systems.

This distinction directly affects heat exchanger selection.

Heat Exchangers for HFC, HFO and Hydrocarbon Refrigerants

Synthetic and hydrocarbon refrigerants may be used in a range of exchanger constructions depending on:

• Pressure

• Temperature

• Material compatibility

• Lubricant

• Safety classification

• Refrigerant charge

• Local codes

Hydrocarbon systems additionally require careful safety engineering because of refrigerant flammability.

Compatibility should always be confirmed for the specific refrigerant rather than assumed from exchanger type alone.

Refrigerant Charge and Internal Volume Considerations

Heat exchanger internal volume can affect total refrigerant charge.

Compact plate and microchannel designs can offer low internal volume in appropriate applications, but refrigerant charge should be evaluated at system level rather than used as the only selection criterion.

Step 5: Choose the Evaporation Method

The evaporator type alone does not define how refrigerant is supplied to it.

Industrial refrigeration commonly uses several circulation methods.

Direct Expansion Evaporators

In a direct-expansion or DX evaporator, refrigerant is expanded through a control device and evaporates as it passes through the heat exchanger.

When DX May Be Suitable

DX configurations can be attractive where:

• Refrigerant charge reduction is important

• Suitable distribution can be achieved

• Capacity and load range are compatible

• Reliable superheat control is available

Superheat Control and Refrigerant Distribution

Uniform refrigerant distribution is essential.

Poor distribution can leave part of the surface underutilized while creating unstable outlet conditions elsewhere.

Control design is therefore closely linked with exchanger performance.

Flooded Evaporators

A flooded evaporator maintains a large portion of the heat-transfer surface wetted with refrigerant.

Efficiency and Stable Heat Transfer

Flooded designs can provide effective use of heat-transfer surface in suitable industrial systems.

However, they require the surrounding refrigerant-management system to be properly designed.

Refrigerant Charge and Liquid-Level Control

A flooded design may involve greater refrigerant inventory than a low-charge DX configuration.

Liquid separation, level control and oil management therefore become part of the selection process.

Pumped or Overfeed Evaporators

In a pumped system, a pump supplies more liquid refrigerant to the evaporator than is evaporated during one pass.

Danfoss describes pump-circulated evaporators as flooded evaporators that use a refrigerant pump and notes that air coolers in cold stores or freezing tunnels are common applications.

Benefits for Large Industrial Refrigeration Plants

Pump circulation can be appropriate where:

• Many evaporators operate from a centralized system

• Evaporators are located far from the separator

• Stable liquid supply is required

• Large cold-storage or freezing loads are involved

Separator, Pump and Oil-Management Requirements

The evaporator cannot be selected independently from the separator, circulation ratio, refrigerant pump and oil-return strategy.

This is one reason industrial refrigeration selection requires a system-level approach.

Step 6: Compare the Main Heat Exchanger Designs

Now that duty and operating conditions have been defined, exchanger construction can be compared more intelligently.

Brazed Plate Heat Exchangers

Brazed plate heat exchangers contain corrugated plates permanently joined by a brazing process.

Best Applications

Depending on construction and approval, they can be suitable for:

• Liquid chillers

• Evaporators

• Condensers

• Economizers

• Subcoolers

• Heat recovery

Their main advantages are:

• Compact dimensions

• High surface-area density

• Low fluid inventory

• No replaceable plate gaskets

Main Limitations

Because the plate pack is permanently joined, it cannot normally be opened for mechanical plate-by-plate cleaning.

Fluid cleanliness and fouling potential therefore matter.

Brazing material must also be compatible with the working fluid.

Gasketed and Semi-Welded Plate Heat Exchangers

Gasketed plate heat exchangers can be opened for inspection and cleaning.

Cleanability and Capacity Expansion

Depending on frame design and operating limits, additional plates may also allow thermal area to be changed when process requirements change.

This can be valuable for plants where maintenance access and future expansion matter.

Gasket and Material Compatibility

Gasket material must match:

• Refrigerant or process fluid

• Temperature

• Pressure

• Oil

• Cleaning chemicals

Semi-welded designs reduce direct gasket exposure on the welded side and are widely offered for demanding refrigeration applications, including ammonia duties.

Shell-and-Tube Heat Exchangers

Shell-and-tube exchangers remain important in industrial refrigeration because of their robust construction and broad design flexibility.

Flooded and DX Shell-and-Tube Evaporators

Different configurations can support:

• Flooded evaporation

• Direct expansion

• Water chilling

• Brine or glycol chilling

Correct refrigerant distribution, oil return, water velocity and freeze protection must be addressed during engineering.

Water-Cooled Condensers

Shell-and-tube construction can be useful when heat is rejected to cooling water.

Water-side fouling and cleaning access should be considered from the start rather than after commissioning.

Finned-Tube Heat Exchangers

Finned-tube construction is one of the most common solutions for air-side industrial refrigeration.

Industrial Air Coolers

Typical applications include:

• Cold rooms

• Distribution centers

• Food processing

• Freezing tunnels

• Process cooling spaces

Important variables include:

• Tube material

• Fin material

• Fin spacing

• Circuiting

• Air volume

• Fan configuration

• Frost conditions

• Defrost system

Air-Cooled Condensers

Finned-tube coils are also commonly used to reject refrigerant heat directly to outdoor air.

Outdoor construction must account for fouling, corrosion and climatic exposure.

Microchannel Heat Exchangers

Microchannel heat exchangers typically use compact aluminum multi-port tubes and fins.

Compact Size and Low Refrigerant Charge

Potential advantages include:

• Compact construction

• High surface-area density

• Relatively low internal volume

• Reduced weight in suitable designs

Fouling, Corrosion and Repair Considerations

Application evaluation should also include:

• Air-side dust

• Salt exposure

• Cleaning method

• Fin damage

• Field repair strategy

• Alloy/coating selection

The most compact exchanger is not necessarily the best exchanger for every industrial site.

Plate-Fin Heat Exchangers

Plate-fin exchangers provide very high heat-transfer surface density in a compact volume.

Compact Industrial and Low-Temperature Applications

They can be useful for specialized duties where compactness and close temperature approaches are valuable.

However, fluid cleanliness, construction material, internal passage geometry and repair strategy must be evaluated carefully.

Step 7: Evaluate Pressure Drop and Energy Consumption

Heat-transfer performance cannot be optimized without considering pressure drop.

Refrigerant-Side Pressure Drop

Excessive refrigerant pressure loss can change the effective evaporation or condensation condition and affect system performance.

This is particularly important in:

• Low-temperature suction-side equipment

• Long refrigerant circuits

• Two-phase flow

• Refrigerant distributors

Air-, Water- and Brine-Side Pressure Drop

Higher pressure drop usually means that fans or pumps must provide more power.

For liquid circuits, designers should evaluate:

• Heat exchanger pressure loss

• Pipe losses

• Valve losses

• Filter losses

• Available pump head

Air-side pressure loss similarly interacts with fan selection.

Balancing Heat-Transfer Performance Against Pump and Fan Power

Increasing velocity may improve heat transfer, but it can also increase pressure loss.

Selection is therefore an optimization problem rather than a search for the maximum possible heat-transfer coefficient.

Why the Lowest Initial Cost May Not Produce the Lowest Operating Cost

A cheaper exchanger that produces excessive pressure drop or poor heat rejection can increase operating cost over many years.

That is why exchanger selection should consider total energy consumption, not simply purchase price.

Step 8: Check Materials and Corrosion Resistance

Material selection is fundamental to heat exchanger life.

Tube, Plate and Fin Material Options

Depending on construction, common materials can include:

Copper

Common in many refrigeration coils and heat exchangers, provided the refrigerant and process fluid are compatible.

Aluminum

Widely used for fins and all-aluminum microchannel designs because of its thermal and weight characteristics.

Stainless Steel

Commonly used where corrosion resistance, cleanliness or refrigerant compatibility requires it.

Titanium and Copper-Nickel Alloys

These may be considered for particular water qualities or corrosive duties, but material selection should always be based on actual fluid chemistry and project conditions.

Material Compatibility with Refrigerants and Secondary Fluids

Check compatibility with:

• Refrigerant

• Compressor oil

• Water chemistry

• Glycol concentration

• Brine

• Cleaning chemicals

• Process contamination

A material that performs well with one medium may perform poorly with another.

Coastal, High-Humidity and Chemically Aggressive Environments

Coastal or industrial environments may expose air-side equipment to:

• Chlorides

• High humidity

• Chemical vapors

• Dust

• Acidic or alkaline contaminants

Material and coating requirements should therefore be defined according to the real site environment.

Protective Coatings and Their Practical Limitations

Coatings can improve corrosion protection, but they are not a substitute for correct base-material selection.

Their performance depends on:

• Surface preparation

• Coating chemistry

• Application quality

• Thickness

• Damage during installation

• Cleaning practices

Step 9: Account for Fouling, Frost and Maintenance

A heat exchanger rarely operates indefinitely under clean laboratory conditions.

Water-Side Scaling and Biological Fouling

Hard water, contaminants and biological growth can reduce heat-transfer performance.

Where fouling is expected, consider:

• Water treatment

• Filtration

• Fouling allowance

• Cleaning access

• Removable covers

• Plate disassembly

• CIP connections

Dust and Debris on Air-Side Coils

Outdoor condensers and dry coolers can accumulate:

• Dust

• Fibers

• Pollen

• Sand

• Process debris

A heat exchanger for a dusty industrial location may therefore require different fin spacing and cleaning access from one installed in a clean environment.

Frost Accumulation on Industrial Air Coolers

Frost adds thermal resistance and restricts airflow.

Selection should consider:

• Fin spacing

• Defrost type

• Defrost interval

• Drainage

• Fan operation during defrost

• Moisture load

Mechanical Cleaning vs Cleaning in Place

The ideal cleaning method depends on construction.

For example:

• Gasketed plate exchangers can be opened.

• Some shell-and-tube units allow mechanical tube cleaning.

• Brazed plate exchangers generally depend on suitable CIP procedures where cleaning is necessary.

Cleaning strategy should therefore be part of equipment selection.

Maintenance Access, Spare Parts and Planned Downtime

Ask practical questions before ordering:

• Can technicians reach the exchanger?

• Can tubes or plates be cleaned?

• Is there enough clearance to remove components?

• Are gaskets or fans replaceable locally?

• How long can the plant tolerate shutdown?

Maintenance cost can exceed the difference in initial purchase price.

Step 10: Consider Installation and Operating Conditions

Good thermal calculations can still result in a poor project if site conditions are ignored.

Indoor vs Outdoor Installation

Outdoor equipment may require greater attention to:

• Rain

• UV exposure

• Corrosion

• Temperature extremes

• Electrical enclosure protection

• Snow or wind conditions

Available Footprint and Service Clearance

Do not compare equipment dimensions alone.

A compact heat exchanger that cannot be serviced within the available space can become a maintenance problem.

High Ambient Temperature and High Altitude

High ambient temperatures reduce the temperature difference available for air-side heat rejection.

High altitude changes air density.

Both conditions should be provided to the equipment supplier where relevant.

Hot and Dusty Environments

Heat exchanger design for hot, dusty regions should address both thermal capacity and fouling.

Possible considerations include:

• Coil face area

• Fin spacing

• Fan selection

• Cleaning access

• Protective construction

Coastal and Corrosive Locations

Salt-laden air can accelerate corrosion.

Specify the actual site environment instead of simply writing “outdoor use.”

Noise and Fan-Control Requirements

Industrial projects near offices, residential areas or sensitive process zones may require fan-speed control or other noise measures.

Noise targets should therefore be specified during selection.

Step 11: Compare Lifecycle Cost, Not Only Purchase Price

The lowest quotation is not necessarily the lowest-cost solution.

Initial Equipment and Installation Cost

Consider:

• Equipment

• Piping

• Supports

• Controls

• Pumps

• Fans

• Installation labor

Compressor, Pump and Fan Energy

Small differences in pressure drop or heat-rejection temperature can accumulate into significant energy differences over long operating hours.

Refrigerant Charge and Leakage Risk

Refrigerant inventory affects:

• Initial refrigerant cost

• Safety strategy

• Environmental exposure

• Leakage consequences

• Service requirements

Low-charge design can therefore be valuable, but it must still satisfy capacity and maintainability requirements.

Cleaning, Repair and Replacement Cost

Estimate how often the exchanger will require:

• Cleaning

• Gasket replacement

• Fan servicing

• Coil repair

• Water treatment

• Chemical cleaning

Expected Downtime and Production Losses

For food, pharmaceutical and continuous-process plants, downtime may cost more than the equipment itself.

Serviceability therefore deserves considerable weight during selection.

Heat Exchanger Selection Matrix by Industrial Application

Different refrigeration applications place different priorities on heat exchanger design.

The matrix should be used to narrow the options rather than replace thermal calculations.

Common Heat Exchanger Selection Mistakes

Selecting by Nominal Capacity Alone

“500 kW heat exchanger” is not a complete specification.

Capacity depends on temperature, refrigerant state, fluid flow and pressure conditions.

Ignoring Pressure Drop

A thermally adequate heat exchanger can still be a poor system choice if pressure drop is excessive.

Using Maximum Operating Pressure as Design Pressure

Operating pressure and design pressure are not interchangeable.

The required mechanical design must reflect applicable codes and the complete pressure/temperature envelope.

Overlooking Refrigerant and Material Compatibility

Never select material only according to price.

Ammonia and copper-containing construction provide a clear example of why compatibility matters.

Ignoring Part-Load Performance

Industrial refrigeration systems may spend much of their operating life below peak design load.

Controls, refrigerant distribution and fan/pump modulation therefore matter.

Failing to Plan for Cleaning and Maintenance

Fouling is not merely a future maintenance problem. It is a selection criterion.

Treating a Dry Cooler as a Refrigerant Condenser

A dry cooler and an air-cooled refrigerant condenser may look similar externally, but they perform different system duties.

A dry cooler normally rejects heat from a secondary liquid circuit such as water or a water-glycol mixture.

An air-cooled condenser receives refrigerant vapor directly and rejects heat while the refrigerant condenses.

This difference affects:

• Internal circuit design

• Pressure rating

• Tube selection

• Connections

• Controls

• Thermal calculation

The two should not be treated as interchangeable equipment.

What Information Does a Manufacturer Need for Heat Exchanger Selection?

The quality of the manufacturer's selection depends heavily on the quality of the operating data supplied.

Sending only:

“Need 200 kW heat exchanger”

is normally insufficient.

Required Thermal Data

Cooling or Heat-Rejection Capacity

Provide required capacity in kW, MW or another clearly defined unit.

Fluid and Refrigerant Names

Specify:

• Primary refrigerant

• Secondary fluid

• Glycol/brine type

• Concentration if applicable

Inlet and Outlet Temperatures

Provide target temperatures for each fluid side.

Flow Rates or Enthalpy Data

For liquid circuits, provide flow rate where known.

For refrigerant duties, provide sufficient thermodynamic state information for reliable calculation.

Required Mechanical Data

Operating and Design Pressure

Provide both where available.

Maximum and Minimum Temperature

This is especially important for low-temperature refrigeration and high-pressure heat recovery.

Allowable Pressure Drop

Specify acceptable pressure loss on each circuit.

Connection Size and Direction

Include:

• Pipe size

• Connection standard

• Preferred orientation

• Inlet/outlet position

Required Site and Commercial Data

Ambient Conditions

Provide:

• Design dry-bulb temperature

• Humidity where relevant

• Altitude

• Coastal exposure

• Dust conditions

Installation Space

Include maximum:

• Length

• Width

• Height

and required service clearances.

Power Supply for Fans

For air-cooled equipment, specify available:

• Voltage

• Frequency

• Phase

Material and Coating Requirements

State any project requirements for:

• Tube

• Fin

• Plate

• Casing

• Coating

Applicable Codes and Documentation

Identify required:

• Design code

• Inspection documentation

• Material documentation

• Pressure or leakage testing

• Project-specific certification

These requirements should be confirmed before manufacturing rather than after the unit is completed.

Industrial Refrigeration Heat Exchanger RFQ Checklist

When requesting a quotation from a heat exchanger manufacturer, provide as many of the following parameters as possible:

• Application: cold storage, chiller, process cooling, freezing, etc.

• Heat exchanger duty: evaporator, condenser, gas cooler, dry cooler, oil cooler, subcooler or heat recovery

• Refrigerant: R717, R744 or other refrigerant

• Secondary fluid: water, glycol, brine or process fluid

• Fluid concentration: where applicable

• Required capacity: kW or MW

• Refrigerant operating condition

• Fluid inlet temperature

• Fluid outlet temperature

• Flow rate

• Operating pressure

• Required design pressure

• Allowable pressure drop

• Minimum and maximum ambient temperature

• Site altitude

• Indoor or outdoor installation

• Corrosive, coastal or dusty environment

• Preferred materials

• Fouling conditions

• Maximum dimensions

• Connection size and standard

• Applicable design standard

• Required inspection or material documentation

• Power supply for fans, if applicable

Providing this information at the RFQ stage allows the supplier to compare configurations using actual operating conditions instead of selecting equipment from nominal capacity alone.

How Aidear Supports Custom Industrial Refrigeration Projects

Industrial refrigeration projects often require heat exchangers designed around specific operating conditions rather than a single standard model.

Available Heat Exchanger Technologies

Aidear's refrigeration and heat-transfer product range includes solutions such as:

• Finned-Tube Heat Exchangers

• Microchannel Heat Exchangers

• Shell-and-Tube Heat Exchangers

• Plate Heat Exchangers

• Plate-Fin Heat Exchangers

• Dry Coolers

• Industrial Air Coolers

This makes it possible to evaluate different heat exchanger structures according to the actual refrigeration duty instead of forcing every project into one product category.

Thermal and Structural Customization

Depending on project requirements, selection can consider parameters such as:

• Heat-transfer capacity

• Working medium

• Inlet and outlet temperatures

• Flow rate

• Pressure

• Materials

• Dimensions

• Connection arrangement

• Airflow requirements

• Installation conditions

Pressure, Leakage and Material Verification

For industrial heat exchanger projects, required pressure testing, leakage testing, material documentation and other inspection requirements should be confirmed according to the specific order and applicable project requirements.

They should not be assumed to be identical for every product or project.

From Operating Data to a Custom Heat Exchanger Solution

For the most useful technical evaluation, send the complete operating conditions rather than only a desired product name.

For example, instead of requesting:

“I need a shell-and-tube heat exchanger.”

provide:

“We need to cool 30% glycol from 10°C to 5°C at a specified flow rate using our refrigeration system, with a defined design pressure and allowable pressure drop.”

That allows engineers to evaluate whether shell-and-tube, plate or another configuration is technically appropriate.

Conclusion: Select the Heat Exchanger Around the Complete Operating Envelope

Selecting a heat exchanger for industrial refrigeration should not begin with a product catalogue.

Begin with the system duty.

Then define:

Duty → Capacity → Temperature Program → Refrigerant → Evaporation Method → Heat Exchanger Type → Pressure Drop → Materials → Fouling & Maintenance → Installation Conditions → Lifecycle Cost

This sequence avoids one of the most common refrigeration procurement problems: selecting equipment based on nominal capacity while ignoring the conditions that actually determine system performance.

A heat exchanger that performs well in one refrigeration plant may be inappropriate for another plant with the same nominal capacity because the refrigerant, temperatures, pressures, air conditions, secondary fluid or maintenance strategy are different.

For industrial cold storage, process cooling, freezing, chillers or heat-recovery projects, provide the complete operating conditions before final equipment selection.

Need help selecting a heat exchanger for your refrigeration project?

Send Aidear your refrigeration duty, refrigerant, required capacity, inlet and outlet temperatures, flow rate, operating/design pressure, allowable pressure drop and installation conditions.

We can use these operating parameters to evaluate a suitable heat exchanger configuration for your industrial refrigeration application.