Project Overview
This project involved the supply of a skid-mounted falling film chiller (pillow plates) developed for a dairy production line where low-temperature chilled water stability was as important as nominal cooling capacity.
The design basis required the system to use ammonia (R717) and deliver 1100 kW of cooling duty while reducing process water temperature from 13°C to 0.5°C at a flow rate of 75 m³/h. For dairy applications, this type of duty is not only about removing heat. It is about maintaining stable process conditions, supporting product quality, and keeping the overall cooling package practical for plant operation.
A falling film arrangement was selected because it offers a more controlled refrigerant distribution pattern, lower refrigerant inventory compared with flooded concepts, and a compact skid structure that can be integrated into real industrial projects without turning the equipment into an oversized installation.
Design Basis
Why a Falling Film Chiller Was the Right Fit
Lower Refrigerant Inventory
A falling film design allows the heat transfer surface to operate with a thin liquid layer rather than a large flooded volume. In ammonia systems, reducing refrigerant charge can be a meaningful practical advantage.
Stable Heat Transfer
For chilled water duty near the freezing range, stable surface wetting and controlled distribution support more predictable heat transfer and more reliable temperature performance.
Compact Project Package
The modular skid arrangement combines the evaporation section, distribution logic, and water-side structure into one engineered package that is easier to manage during installation and startup.
In dairy processing, the objective is not simply to install a chiller with a large nameplate. It is to produce cold water reliably, avoid unnecessary operating instability, and keep the final package practical for cleaning, maintenance, and long-term plant use.
System Configuration
The supplied package was built around three evaporation plate groups. Each group used SUS316L plates with a plate size of 1.5 m × 1.5 m and 12 plates per group, giving a total of 36 plates across the full unit.
Main Package Elements
- 3 evaporation plate groups
- 12 plates per group, 36 plates total
- 3 water distributors with 12-slot design
- 3 collection headers in SUS316L
- 1 insulated water tank with 50 mm insulation
- 1 stainless steel external skid frame
Construction Details
- Evaporation plates: SUS316L
- Water distributors: SUS304
- Collection headers: SUS316L, φ133 × 4
- Water tank: SUS304, 3000 × 2000 × 700 mm
- Tank volume: approximately 3.9 m³
- Frame: SUS304 square tube 50 × 50 × 2.5 mm
Technical Points That Mattered in This Case
Material Logic
SUS316L was selected for the evaporation plates because corrosion resistance is most critical where heat transfer and liquid distribution happen directly. SUS304 was retained for the shell, frame, and external structure to keep the overall package practical from both construction and cost perspectives.
Pressure Test Requirement
The proposal specified a 22 bar test pressure and nitrogen holding at 20 bar for 24 hours. For an ammonia-based package, leak control is not a detail. It is a core design and fabrication requirement.
Ammonia Circulation
Each evaporation plate group required approximately 1000 kg/h ammonia flow, resulting in a total project requirement of around 3000 kg/h across all three groups.
Scope Boundary
The supply scope covered the skid-mounted package itself. External chilled water pumps, external piping, and site installation were excluded. Defining that boundary clearly is important in real project execution because it determines site responsibility, installation planning, and final commissioning logic.
Project Result
This case shows what a falling film chiller should look like when it is developed from an actual process requirement rather than from a generic catalog concept. The project combined substantial cooling duty, ammonia refrigeration, and food-process-oriented construction into one skid package capable of supporting stable chilled water production for dairy use.
The delivered solution achieved 1100 kW cooling capacity, 75 m³/h chilled water service, and a temperature reduction from 13°C to 0.5°C, while maintaining a compact package layout that balanced thermal performance with practical installation logic.
Where This Type of System Fits
Although this project was developed for dairy process cooling, the same engineering approach is relevant in other industrial duties where chilled water stability, refrigerant control, and compact project packaging matter.
Dairy Processing
Stable low-temperature water for process lines where product quality and production rhythm depend on reliable cooling control.
Food & Beverage Plants
Process cooling applications where stainless steel construction and practical skid integration are important.
Pharmaceutical Utilities
Cooling duties where controlled water temperature and consistent evaporator performance support plant reliability.
FAQ
Why use ammonia R717 in a falling film chiller?
Ammonia R717 is widely used in industrial refrigeration because of its strong thermodynamic performance. In a falling film design, it also benefits from lower refrigerant inventory compared with more heavily flooded concepts.
Is a falling film chiller suitable for dairy cooling?
Yes. Dairy cooling often depends on stable chilled water supply rather than peak capacity alone. A properly designed falling film chiller supports that requirement well.
What is the main advantage over a flooded evaporator concept?
The main practical advantages are lower refrigerant charge, more controlled liquid distribution, and a compact package structure that can be easier to integrate into industrial projects.
Can this kind of equipment be delivered as a skid package?
Yes. This project was built as a skid-mounted package, combining the evaporator groups, distribution system, water tank, and frame into one engineered unit.
What chilled water duty was required in this project?
The system was designed to cool water from 13°C to 0.5°C at 75 m³/h, corresponding to a total cooling duty of 1100 kW.
What materials were used in this falling film chiller?
The evaporation plates were specified in SUS316L, while the shell, frame, and several structural components were built in SUS304.
Was the external pump and site installation included in the supply scope?
No. The supply scope excluded the external chilled water pump, external piping, and site installation work.
How many evaporation plate groups were used?
The system used three evaporation plate groups, with 12 plates per group and 36 plates in total.
