Falling Film Chiller

Falling Film Chiller Process reliability to produce constant cooling of ice water near freezing point

Falling Film Chiller or so-called baudelot ice water cooler are mainly designed for cooling water down to 0.5°C near freezing point. Especially Ice water (near 0°C) has a very good heat capacity, i.e. by contrast with other cooling agents, relatively small quantities can convey a large amount of heat.

What makes the falling-film chiller so interesting is its relatively simple and relieble operation including a high cooling performance to represent the ideal industrial water chiller. Water flows down the vertical plates. It is an open system that is accessible for cleaning, even during operation. Completly made out of stainless steel.

Visualization for understanding the working principle of a falling-film chiller

What are the advantages with Falling Film Chillers?

  • No risk of freezing with ice water of 0.5 °C and destruction of the aparatus
  • Water chiller with low cost per kWh, High efficiency & low pressure drop 
  • Simplicity of control
  • Fully welded, no spare parts such as seals in this industrial water cooling chiller
  • Easy access to the open system industrial water chiller and easy to clean even during operation
  • Suitable chiller for contaminated liquids (for example greywater or red water)
  • Low tendency to fouling
  • Industrial water chiller completely made of stainless steel, also for salt water

Why a Water Chiller?

Furthermore water near freezing point at 0.5°C is an important part in food refrigeration, to ensure the fastest possible cooling of the product due to the best possible product quality. The open, non-pressurized water side of this Falling Film Chiller or baudelot ice water cooler allows inspections and cleaning of dirt without disassembly in a few minutes. There are no additional costs for planning, piping, mounting of the valves and eletric wiring, as well as setting and programming of controllers, like known with Plate-Heat-Exchangers. No gaskets.

Most noteworthy Ice water at 0.5°C can cool large produce in very short period of time. Similarly blanching, cooling and washing processes are mainly focussed as well as mixing processes with any requirement of low temperatures while or right after mixing processes. There are various detailed sanitary adjustments for the standard Falling Film Chiller due to different process requirements in use. But the appropriate adaptation can be just as good, as the information, given by the customer, concerning the application on site.

What’s a Falling Film Chiller?

How does a Falling Film Chiller work?

The Falling Film Chiller or so-called baudelot ice water cooler consists of a distribution tray for the water at the top, a heat exchange system, a frame and a cover and a bottom collecting tank for water (optional). Water is pumped into the distribution tray and at a controlled rate is distributed homogeneously by a distribution through onto vertical panels in an open system.

The process water flows in a thin film over the outer surface down on the panels and obtains the highest possible outside film coefficient. By highest descent speed, highest U transmission coefficients are reached.

In order to avoid building of ice at the panels, the suction gas pressure at the evaporator suction header has to be regulated. To keep the evaporation temperature not lower than the designed one, e. g. -3°C, as well as the water temperatures and flow. At systems used with e. g. glycole inside, the glycol inlet temperature has to be controlled. 

Nowadays, falling film chillers are mostly used in combination with plate heat exchangers in dairies. Due to hygiene regulations, there is a strict separation between a closed ice water circuit using a primary refrigerant (such as ammonia or refrigerants like R449A, R448A, R407C, R407F, R410A, or CO2) and a closed milk circuit using a plate heat exchanger. In contrast, the use of a primary refrigerant has even shifted towards the use of secondary refrigerants (glycols, brines, etc.). For example, recent market trends indicate an increased preference for primary refrigerants due to better cost-effectiveness, or even the environmentally friendly option of an ecological refrigerant (CO2).

A high flow velocity ensures highly efficient heat transfer and a kind of a helpful self cleaning effect, which allows the operation with polluted liquids as well. Completely made out of stainless steel, it assures all required sanitary requirements, as the Ice water is always in contact with stainless steel parts AISI 304 or 316L or higher stainless steel grades up to titanium.

An industrial cold water chiller consists of essential components including compressors, condensers, expansion valves, and evaporators. The process operates as follows: The compressor compresses the refrigerant gas, increasing its pressure and temperature. The high-pressure and high-temperature refrigerant gas then flows to the condenser, where it releases heat and condenses into a high-pressure liquid. The liquid high-pressure refrigerant passes through the expansion valve to decrease its pressure and temperature. The resulting substance flows to the evaporator, where it absorbs the heat from the water to be cooled. This heat transfer occurs as the water passes through a falling film chiller. The chilled water circulates back to the application (process) that needs to be cooled. The low-pressure and low-temperature refrigerant gas then returns to the compressor. The cycle can be repeated as needed.

Comparison of Falling Film Chillers and Plate Heat Exchangers

If you are an engineer looking for the most efficient and effective process cooling solutions of ice water near freezing point of 0,5°C, then you should consider the advantages of a falling film chiller versus a plate heat exchanger. This type of chiller offers some very distinct benefits when compared to plate heat exchangers and could be just what your application needs. We’ll explore how each type of solution works, discuss the various pros and cons associated with both types of chillers, and provide advice on making the best choice for your project. By examining all of these elements, you’ll gain a better understanding as to why falling-film technology may be preferable over traditional plate heat exchangers in certain projects.

The Falling Film Chiller is a specialized engineering solution, designed with Pillow Plates arranged side-by-side in an efficient frame. As the interior of each plate undergoes evaporation with ammonia or refrigerant, water streams down along the exterior to create thin films for heat exchange - enabling temperatures near freezing point and optimized efficiency far beyond HVAC applications. With precisely spaced plates at 50/150mm apart from one another complemented by 0.5/0.4 mm thick fluid layers transitionally descending downwards – this product ensures successful thermal energy transfer without fail!

The FALLING FILM CHILLER, a widely-employed technological solution for businesses in both the food and beverage industry as well as chemical and pharmaceutical sectors abroad, relies on optimized film layer thickness to achieve better exchange coefficients. A thinner falling film is associated with higher levels of efficiency while increased plate numbers will result in thicker layers that reduce overall performance. 

The simplicity of a Falling film chiller with open design to produce water at 0,5°C

  • Fully welded, no spare parts such as seals.
  • Easy access to the open system industrial water chiller and easy to clean even during operation.
  • Falling-Film-Chillers need mainly shut valves on suction and liquid.
  • Suitable chiller for contaminated liquids (for example greywater or red water)
  • Low tendency to fouling.

In direct contrast to the Plate Heat Exchanger:

  • Need seals to be exchanged periodically.
  • For cleaning, the unit must be stopped and dismantled. This costs time and interrupts the production process.
  • Hot gas-defrost and flow control on the water side, costs for the controllers and temperature sensors do not depend on the capacity.
  • Additional cost incurred due to the planning, piping, mounting of valves and electric wiring as well as setting and programming of the controller.
  • Contaminated media in the inner channels of the plates, especially in the pathes, pose a major problem of ice formation and mechanical destruction of the entire apparatus.

To give you an idea of the difference to a Plate Heat Exchanger, here is an excerpt from a manual of a well-known Plate Heat Exchanger manufacturer:

“Despite all mentioned advantages of Plate Heat Exchanger, it has to be told, that the Plate Heat Exchanger ice water plant needs special control features and a careful operation (according to the water temperature near freezing point). It has to be secured, that the water temperature on the waterside of the plates never undergoes 0.5 °C. Suction pressure control is recommended. The suction pressure regulator has to have an accuracy of 0.25 °C (at the ice water probe). A regulation valve is necessary.”

In conclusion,plate-heat-exchangers require temperature control, hot gas-defrost and flow control on the water side. The costs for the controllers and temperature sensors do not depend on the capacity while control valves, pilot valves as well as solenoid valves and shut valves are dependent on capacity. Having said that it should be taken into account that there could be enormous additional cost incurred due to the planning, piping, mounting of valves and electric wiring as well as setting and programming of the controller. Plate-Heat-Exchangers have gaskets between plates likely needing cleaning depending on various water qualities causing massive lose of power if overlooked.

For further guidance, please get in touch with our engineers who are ready to offer personalized advice tailored specifically to your requirements for your next 0,5°C ice water project.

Industrial Applications for Industrial Water Chillers

What’s the Process?

The water cooling system with falling film chillers is becoming increasingly established as an efficient and cost-effective solution for heat dissipation in industrial applications. The use of falling film chillers is suitable wherever different consumers such as processes or individual machine parts such as spindles, motors, or hydraulic devices need to be economically supplied with a cooling system. In addition, a customized water cooling system is an optimal solution for demanding conditions such as high ambient temperatures and heavy dirt.

In the Falling Film Chiller or baudelot industrial water chiller the homogeneous falling film allows to chill water down to 0,5 °C. Within industrial processes it can function as pre-chiller for industrial ice bank systems or is connected to the ice water side of a Plate Heat Exchanger. Or will be pumped directly to various food cooling processes. From the water collecting tank under the Falling Film Chiller pumps to bring the chilled water to the desired consumption locations.

Our devices generate a maximum power reserve in production with this baudelot ice water cooler at this temperature. Different from Plate-Heat-Exchangers, there is no need of temperature control, hot gas-defrost or flow control on water side. Costs for controller and temperature sensor do nor depend on the capacity. Control valves and pilot valves as well as solenoid valves and additionl shut valves are dempendent on capacity.

An industrial cold water cooling system with falling film chillers is a type of water cooling that extracts heat from a heat source while ensuring constant temperatures, pressures, and flows through a cooling system. Simply put, an industrial cold water cooling system works by circulating a cooling fluid from a reservoir to the devices that need to be cooled. This differs from other cooling systems, such as air-based systems, which use fans for heat dissipation.

Industrial cold water cooling systems with falling film chillers have become popular in various cooling and large-scale installations due to their higher efficiency compared to certain air cooling systems. However, their suitability needs to be evaluated on a case-by-case basis. This decision is indeed crucial as choosing the right type of cooler can help businesses save costs, reduce downtime, and improve energy efficiency.

As mentioned earlier, industrial cold water cooling systems with falling film chillers are part of cooling systems that are responsible for removing unwanted heat from a source. There are various applications where this can be useful, such as plastic processing processes, including various operations in mechanical forming, metal and machinery manufacturing, reducing issues like thermal deformation and improving accuracy, the food and beverage industry, chemical and pharmaceutical production, medical facilities for operating systems like MRIs or X-ray machines, as industrial cold water cooling systems to supply multiple buildings or facilities with chilled water through a pipeline network, or even in modern data centers, where they contribute to the cooling of equipment to ensure their operation within safe temperature ranges.

Industrial Ice water chiller in dairy processes

A Falling Film Chiller or baudelot ice water chiller continuously generates ice water at 0.5 ° C without ice formation. Ice water is the ideal cooling medium for milk-processing plants, because it is non-toxic, has excellent heat transfer and transport properties, is inexpensive and available everywhere. To meet high global quality standards, fast and smooth cooling processes must be guaranteed from processing to storage of sensitive dairy products such as milk, milk powder, yoghurt, milk desserts, butter and cheese, mostly at the expense of high energy costs.

Milk processing plants are therefor looking for partners such as Heat Transfer Technology AG in order to realize saving potentials in the field of ice water technology. In order to expand the capacity of a dairy, operators often install additional ice water storage tanks. This is associated with high financial cost and space requirements. A corresponding alternative is the use of a Falling Film Chiller for ice water pre-cooling. In addition to the robust, simple operation and high energy efficiency, the advantages are that ice water temperatures between 0°C and 1°C can be generated without risk. Falling-Film Chiller cool the returning water, before it enters the ice water storage tank, thus relieving the existing plant.

Low-specific and thermodynamic parameters from an industrial water chiller of ice water near freezing point

As zero point is approached, the problems in ice water production with the attendant risk of ice formation increase. The known anomaly of water (lowest specific volume at 4°C) results in the water volume expanding when it freezes, and under certain circumstances this can cause destruction of the equipment used. Furthermore, ice formation in ice water systems with their thick layers of ice always involves considerable performance losses because the ice layer acts like insulation and greatly reduces the thermal transmission output.

Consequently ice water production calls for a technique that on the one hand brings the water temperature as close as possible to zero point, but on the other hand is not susceptible to potential ice formation. If control fluctuations of the cooling system lead to ice formation, a layer of ice on the panels will reduce the heat transfer and reduce the cooling power of the baudelot ice water cooler. Building of ice at the panels may occur for some minutes, but there will not follow any mechanical destruction as in Plate Heat Exchangers. Ice will melt automatically after raising of the temperature inside the panels within the next normal operation mode cycle.

The flow-specific and thermodynamic parameters of water are favorable, so that high heat transfer rates can be achieved. However, the freezing point of the water itself (zero point) sets crucial physical boundaries for ice water production and cooling with ice water. Above all, temperatures achievable in the water are made to approach the zero point as closely as possible in order to exploit maximum temperature differences for the products to be chilled with ice water and to keep the temperature of the cooled product as low as possible.

Process water chiller with discontinuous inlet water flow

This Falling Film Chiller or baudelot ice water cooler is designed to be robust to unexpected fluctuations in operation. For this purpose we use a split-tank-design is the optimal solution for cooling water with inconsistent flow rates or temperatures, ensuring that your refrigeration machine operates continuously and efficiently.

The Falling Film Chiller or Baudelot ice water cooler achieves this by incorporating a custom-designed water reservoir and flow path that caters to the specific flow profile and temperature variations of your application. This unique design ensures the chiller is resilient to unforeseen operational shifts while maintaining high-performance levels. Additionally, by employing food-grade stainless steel in its construction, the Ice Water Falling Film Chiller meets all necessary standards for use in the food and beverage industry, ensuring a hygienic and reliable cooling solution for your business.


Falling Film Chiller versa Ice Bank

Ice storage adapts quickly to changing cold demand. This applies to energy consumption, energy costs, investment costs, as well as availability of space and electricity. Most often, our customers are faced with the choice of a storage system or a Buco spray cooler, a falling film chiller. By using storage, high peak cold consumption can also be managed with cooling systems that are only designed for the daily average value. There is no doubt that an ice storage system can be operated more efficiently by taking advantage of the favorable off-peak hours.

On the other hand, Buco spray coolers, falling film chillers are much cheaper to purchase and, in addition to lower energy consumption, also require less space. The past clear advantage of storage in the use of partial load operation has diminished over the years and has become differentiated in that spray coolers can also be used in partial load operation with fluctuations in water temperature or quantity.

Our falling film chiller is a special heat exchanger designed with pillow plates to create an evaporation environment inside, while the outside of each pillow plate allows for even distribution of water, forming a thin film measuring 0.5-0.4 mm in thickness as it flows down each plate, supporting efficient cooling or heating applications in industrial technology.

Falling film chiller technology has revolutionized the technical industry, especially in the food and beverage industry, as well as in the chemical and pharmaceutical industries. The exchange coefficients depend on how thin or thick the water film flows down or is applied to the plates - thinner layers result in higher exchange coefficients. However, the use of a smaller number of plates with the same water flow rate can lead to thicker films that lower the exchange coefficients.

De-oiling device of an industrial water chiller

If the Falling Film Chiller is used with NH3, a de-oiling device for the system is provided as a small suction pipe at the liquid bottom header of the system for gravity or pump operation. This is standard for NH3 and done on request for CO2. With refrigerant NH3, and depending on the oil, probably as well for CO2, there are severe miscibility gaps or solubility gaps with different oils, even if helpful additives are used. Prior to the de-oiling procedure the evaporator system must be out of operation for some time, to allow the oil to separate to the bottom of the system.

In case of using oil with a lower density compared to the liquid refrigerant CO2, the refrigerant has to be evaporated completely for this de-oiling function. A regular de-oiling is needed, according to the properties of the refrigerant compressor and the oil. Experienced engineers with academic advice are responsible for the design. Individual channel design and construction for each project due to the high inside film coefficient and low pressure drop.

Why mainly NH3?

The natural refrigerant ammonia, which is not only climate-neutral, but also highly energy-efficient, is normally used. Due to its very good thermodynamic properties, ammonia requires the least amount of energy to generate a certain cooling capacity.

This advantage is particularly important in dairies with their large plants, so that refrigeration plants using ammonia have proven their worth in the milk processing industry. At the same time the ammonia volume in this system is low. Gravity-driven evaporators with separators are used. In this way, the efficiency of the system is increased compared to plants with direct expansion and energy costs are reduced. For heat recovery, effective systems use an evaporative condenser, a heater and oil cooler. All in all, this increases the efficiency of the entire system an reduces operating costs.

The Baudelot cooler

Historical review and beginnings of an industrial chiller

Jean Louis Baudelot (1797–1881), was born in France, and studied engineering in Belgium. Though he claimed several inventions, fame came in 1856, when he patented a liquid cooler. Specifically intended for the brewing industry.

A cousin who was a brewer presented him with the fact that until then beer worts had to be cooled in a shallow vessel (cool ship) and stirred during a whole night—a process that easily took 8 hours. Worse, the continuous exposure of the worts to the air resulted often in unwanted inoculation and infected beer. Yet exposure was mandatory because beer yeasts need oxygen at the outset of fermentation. Therefore, the wort needs to be well aerated.

Baudelot envisaged a fine double copper sheet overlaying copper tubes (first cylindrical, later elliptical in cross-section) wherein cold water (spring water or icewater) ran countercurrent to the worts. The worts were collected on top of the cooler in shallow tray, and then finely dispersed, flowing over outside of the copper sheets, which were being being cooled internally. In this way, cooling took place in less than a quarter of the original time needed, limiting exposure to contaminating microbes, while aeration was assured. Hot wort flowed like an undulating waterfall down the exterior of the cooler, emerging cool and aerated at the bottom. It was a massive improvement that led to beer of much better quality and stability.


Falling Film Chiller advantages

  • No risk of freezing with ice water of 0.5 ° C
  • Water chiller with low cost per kWh
  • High efficiency, low pressure drop of this industrial water chiller
  • Suitable chiller for contaminated liquids (for example greywater or red water)
  • Easy to clean industrial cooling chiller
  • Cleaning during operation possible with this industrial water chiller
  • Low tendency to fouling chiller
  • No seals in this industrial water cooling chiller
  • No destruction of the apparatus in case of ice formation of this industrial water chiller
  • Special falling film chiller versions as ice water chillers possible

What are Industrial Water Chillers?

Falling-Film Chiller characteristics

  • Industrial water chiller for capacities from 10 kW to 10,000 kW
  • Evaporator for all primary refrigerants (NH3, freons like R449A,R448A,R407C,R407F,R410A or CO2) and operating modes. As well as secondary refrigerants (Any type of Glycol) or for brine operation
  • All stainless steel materials, from AISI304 up to titanium, 254-SMO, Duplex etc.
    This stainless steel execution gives assurance that the chilled water is always and only in contact with stainless steeel parts and can be used directly for the use required
  • Plug-in units up to 100 kW, or for on-site refrigeration systems

Which industrial applications need a chiller?

Falling-Film Chiller applications

  • Industrial water chiller for water cooling down to 0.5°C.
  • Fastest cooling chiller of food close to freezing by high efficiency
  • No risk of freezing damage to food used in fresh produce, meat, fish, seafood etc.
  • Falling Film Chiller are preferred in application of high capacities with limited ground space
  • Falling Film Chiller plates chill liquids to almost refrigerant temperature
  • Ideal for cooling down milk on farms, dairy cooling and dairy products like yoghurt and cheese cooling. As well as for beer, bread dough, pastafish, seafood, fruit and vegetables as well as for food and beverages in general
  • "White Water" chiller for the cooling of vacuum pumps in the pulp and paper industry
  • Waste water chiller from sewage treatment in laundries and public swimming pools
  • Waste water chiller from process and chemical industry plants
  • Cooling water chiller for the chemical and process industry
  • Sea and river water chiller in heat recovery plants or heat pumps.
  • CO2 evaporation in breweries and soft drink producers

Simple Falling-Film Chiller maintenance

  • Comfortable access to the open system
  • Easy to clean:
    • open water distribution tray
    • large discharge opening for the discharge of particles
    • removable side panels
    • open construction plate system

Falling Film Chiller construction and dimensions example

Typical dimensions without tank
L (m) / B (m) / H (m)

Compact system: 1.2 / 0.5 / 1.8
System type A: 2.0 / 2.1 / 2.0
System type B: 3.8 / 2.5 / 2.0

1900 kW baudelot ice water cooler NH3 pumped mode without water collection tank
1900 kW baudelot ice water cooler NH3 pumped mode without water collection tank
100 kW baudelot ice water cooler R404a dx mode with water collection tank
100 kW baudelot ice water cooler R404a dx mode with water collection tank

We have always assimilated engineering science and thermodynamics optimally in the various manufacturing processes.

Thermodynamicists,mechanical engineers and welding engineers define the dimensioning, design and construction of customised heat exchanger panels and systems in materials ranging from mild and austenitic steels through to titanium, and ensure successful distribution of their work worldwide.

In doing so they fall back on production engineering expertise and calculations developed in the course of the past hundred years that are still being continuously optimised in an ongoing process.

In the perception of our customers, the Buco product stands for:

Technical and process-oriented consulting
Thermodynamic efficiency
Quality and longevity