A dairy chiller removes heat from milk-processing equipment or from a secondary chilled-water or glycol circuit. It may support farm bulk-tank cooling, milk pre-cooling, pasteurisation cooling, fermentation-temperature control and central cooling in a dairy plant. Correct selection depends on the product quantity, starting and target temperatures, permitted cooling time and the actual process arrangement—not daily milk volume alone.
GESON supplies dairy and food-process cooling systems for farms and processing facilities. Send the milk or product flow, batch size, temperature profile, cooling time, operating schedule, site climate and electrical supply for an engineering selection.
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Where Dairy Chillers Are Used
| Application | Cooling duty | Selection consideration |
|---|---|---|
| Farm bulk-tank cooling | Remove heat from freshly collected milk and maintain the required storage temperature | Milk quantity per milking, milking duration, bulk-tank capacity and local cooling-time requirements |
| Plate pre-cooling | Reduce milk temperature before it enters the bulk tank | Available cooling-water temperature, milk and water flow rates, and plate heat-exchanger design |
| Pasteurisation cooling | Cool milk after the validated heat-treatment stage | Product flow, heat-recovery arrangement, target outlet temperature and production schedule |
| Cheese production | Control temperatures in vats, jackets or secondary circuits | Recipe stages, batch duration and required temperature stability |
| Yoghurt and cultured products | Stop or control fermentation by reducing product temperature | Batch size, product viscosity, cooling surface and permitted cooling time |
| Ice-cream mix and dairy ingredients | Cool process streams or storage vessels | Product properties, ageing or holding schedule and sanitation boundaries |
| Central dairy plant | Supply multiple consumers through a chilled-water or glycol loop | Simultaneous loads, diversity, redundancy, pumping and future expansion |
Target product temperatures and cooling times must follow the plant’s process specification and the regulations that apply in the destination market. They should not be copied from a generic online table.
Direct Expansion, Chilled Water or Glycol Cooling?
Direct-expansion bulk tank
In a direct-expansion system, refrigerant removes heat through an evaporator incorporated into the bulk tank. This can be compact for farm applications, but the tank and refrigeration package must be selected and serviced as an integrated system.
Chilled-water system
A central chiller supplies cold water to tank jackets, plate heat exchangers or other process users. Chilled water is appropriate where the design temperature remains safely above freezing and where the secondary circuit is protected from contamination.
Glycol secondary circuit
A glycol solution lowers the freezing point of the secondary fluid and may be used when the supply temperature or operating environment creates a freezing risk. For food and dairy projects, the fluid grade and concentration must be selected for the applicable food-safety rules, indirect-contact risk, required temperature and material compatibility. The exact glycol product must be approved by the project owner rather than described only as “food grade.”
The glycol loop must remain physically separated from milk and other products by the specified heat-transfer surface. Hygienic product-contact design, CIP procedures and food-contact materials belong to the product-processing equipment scope and must be coordinated with the chiller system.
How to Calculate the Milk Cooling Load
The theoretical product-cooling duty is based on mass flow, specific heat capacity and temperature change:
Cooling duty (kW) = mass flow (kg/s) × specific heat (kJ/kg·K) × temperature reduction (K)
For a batch, calculate the total heat to be removed and divide it by the permitted cooling time. The engineering selection must then consider additional heat from tanks, piping, pumps, ambient conditions and simultaneous process loads. It should also account for fouling allowance, glycol concentration, design flow, heat-exchanger approach temperature and required redundancy.
Do not select a dairy chiller only from litres of milk per day. The same daily volume can produce very different peak loads. A plant processing one large batch in one hour requires more instantaneous capacity than a plant cooling the same volume steadily over ten hours.
Cooling-Time and Storage-Temperature Requirements
Milk-cooling requirements vary by jurisdiction and operation. As examples, the United States Grade “A” Pasteurized Milk Ordinance includes staged time-and-temperature requirements for raw milk, while European rules use different limits depending on collection arrangements. FAO guidance recommends following the applicable national limits.
Therefore, a GESON selection worksheet should record the customer’s governing standard and required product-temperature profile. The chiller supplier provides thermal capacity and secondary-fluid control; the dairy operator remains responsible for validating the complete food process, monitoring product temperature and maintaining sanitary conditions.
Plate Pre-Cooling and Heat Recovery
A plate heat exchanger can use suitably controlled cooling water to reduce incoming milk temperature before mechanical refrigeration. This may lower the peak load on the bulk tank or central chiller. Performance depends on the cooling-water inlet temperature, flow ratio, heat-exchanger surface area and allowable pressure drop.
In processing plants, heat recovery may transfer useful heat from hot product or the refrigeration condenser to a compatible water circuit. Any recovery proposal must keep potable, product and utility circuits safely separated and must not interfere with validated pasteurisation or sanitation procedures.
Food-Safety and Hygienic Design Boundaries
A dairy chiller is part of the utility system; it is not by itself proof that the entire installation is hygienic or HACCP compliant. The project team should define:
- which surfaces contact milk or other food products;
- approved materials and surface finishes for product-contact equipment;
- the secondary-fluid type, concentration and contamination controls;
- the heat-exchanger arrangement separating product and utility circuits;
- CIP method, cleaning temperature, chemicals and drainage;
- temperature sensors, calibration and recording requirements;
- leak detection and response procedures; and
- the documentation required by the local regulator and customer quality system.
SS304 or SS316L may be specified for selected water- or glycol-side components when required, but the grade must match the fluid chemistry, cleaning regime and project specification. It should not be assumed that every component in every chiller is stainless steel.
System Reliability and Redundancy
Loss of cooling can place stored milk or scheduled production at risk. A commercial dairy project should evaluate staged compressors or multiple chillers, standby pumping, buffer volume, alarm outputs and emergency operating procedures. The required level of redundancy depends on the value of the product, maximum acceptable downtime and availability of service support.
For a central plant, divide the load into base, peak and future requirements. This avoids selecting one large unit that operates inefficiently at low load and allows planned maintenance without automatically stopping every cooling consumer. The exact redundancy available depends on the final equipment quantity, piping and control sequence.
Information Needed for a Dairy Chiller Selection
| Required information | Why it matters |
|---|---|
| Milk or product quantity per batch and per day | Defines total heat load and production profile |
| Incoming and target product temperatures | Defines the product temperature reduction |
| Permitted cooling time | Determines the peak cooling capacity |
| Continuous flow or batch process | Determines how the load changes over time |
| Bulk tanks, jackets and heat exchangers | Defines the interface between product and utility cooling |
| Chilled-water or glycol supply/return temperatures | Supports evaporator and compressor selection |
| Secondary-fluid type and concentration | Affects freezing point, heat transfer, flow and pump power |
| Maximum ambient temperature | Affects air-cooled condenser performance |
| Operating hours and simultaneous loads | Supports staging and diversity calculations |
| Voltage, frequency and phase | Defines electrical configuration |
| Material and sanitation requirements | Defines heat-exchanger, tank, pump and documentation scope |
| Redundancy and future expansion | Supports equipment quantity and control strategy |
Related Dairy and Process-Cooling Resources
- Industrial Glycol Chiller Systems
- How Glycol Refrigeration Systems Work
- Air-Cooled Chiller Systems
- Water-Cooled Chiller Systems
- Chiller Preventive Maintenance Checklist
Frequently Asked Questions
What information is required to size a dairy chiller?
Provide product quantity, starting and target temperatures, required cooling time, continuous or batch operation, secondary-fluid temperatures, maximum ambient conditions, operating hours and electrical supply.
Can daily milk volume alone determine chiller capacity?
No. Peak capacity depends on how quickly the milk must be cooled, the starting and target temperatures, whether production is continuous or batched, and the heat-exchanger and secondary-circuit conditions.
Should a dairy cooling system use water or glycol?
Water may be suitable when the secondary-circuit temperature remains safely above freezing. Glycol may be required for lower temperatures or freeze protection. Fluid type and concentration must meet the process risk assessment and applicable food-safety requirements.
Does glycol contact the milk?
In an indirect cooling system, it must not. Milk and the secondary cooling fluid are separated by the approved tank jacket or heat exchanger. The project design should define contamination protection and leak-response procedures.
What milk storage temperature should be used?
Use the temperature and cooling time required by the applicable national regulation and the dairy’s validated process. Requirements differ by jurisdiction and collection method, so a universal value should not be assumed.
Can one central chiller serve several bulk tanks or process lines?
Yes, if the total simultaneous load, flow, temperature requirements, distribution system and redundancy are correctly designed. Loads with different temperatures may require separate circuits or an intermediate heat exchanger.
What should be included in a dairy chiller quotation?
The quotation should identify rated capacity and input power at the design condition, compressor and refrigerant, evaporator, design flow and pressure drop, pump and tank scope, controls, electrical supply, materials, accessories and factory-test requirements.
Request a Dairy Chiller Selection
Send GESON your milk or product volume, inlet and target temperatures, cooling time, process schedule, secondary-fluid temperatures, ambient conditions and site power. Our engineering team will review the peak load and recommend a suitable configuration.
