90℃ Hot Food Cooled to 10℃ in ≤20 Minutes: Two-Stage Water Capture Configuration of Vacuum Rapid Coolers in an Indonesian Food Factory

Hot food cooling and fruit and vegetable pre-cooling are two different things. Fruits and vegetables are pressed down from ambient temperature after harvest, while hot food is pressed down from a high temperature of 90°C. A batch of braised meat or a tray of cooked food comes out carrying a large amount of sensible and latent heat, and the cooling rate directly determines how long it can be stored and how far it can travel.

This project is in Indonesia, and what it does is turn “hot food cooling” into a process that can be timed on the production line: a single batch of 1,000 kg of cooked food, cooled from 90°C to 10°C, with the cycle kept within 20 minutes.

Project Background

The customer is a food processing enterprise in Indonesia. The products are braised meat, cooked food, and fast-food-type products, and the material specific heat is calculated at 3.6 kJ/(kg·K). The production line output temperature is around 90°C. After output, the entire batch needs to be rapidly and evenly cooled to 10°C before entering subsequent processes.

Indonesia has a tropical climate, and the plan calculates environmental conditions based on a wet-bulb temperature of 28°C. The entire line is configured with 34 units of CVF-1000 class (single-batch 1,000 kg tier) vacuum rapid coolers, using a two-stage water capture plus centralized liquid supply system format. The plan was finalized in June 2026.

Site Challenges

The first is the hot and humid environment. With a wet-bulb temperature of 28°C, the normal-temperature water that the cooling tower can provide is in the 32/37°C range. This water temperature, against the high-temperature, high-humidity water vapor inside the chamber, makes it difficult for single-stage water capture to catch all the water vapor in one pass. The remaining water vapor all falls to the vacuum pump head, which prolongs the cycle and also makes it unstable.

The second is that the heat load is concentrated in the period when the chamber is opened. When 90°C material first enters the chamber, evaporation is at its most intense, and the instantaneous water vapor volume is at its maximum. If a single large machine is selected according to the maximum load across the entire cycle, that machine will be idling at low load for most of the cycle.

The third is the rhythm of the entire line. The 34 units need to run continuously according to the production line rhythm. If cooling water, secondary refrigerant, and vacuum were each equipped with a separate set per unit, the plant room and piping would spiral out of control; centralized liquid supply and centralized monitoring are the prerequisites for this plan to be implemented.

Plan and Configuration

The plan is configured with 34 units of CVF-1000 class vacuum rapid coolers. Each unit has a primary water catcher connected to normal-temperature water and a secondary water catcher connected to -5°C calcium chloride (CaCl₂) secondary refrigerant, with the two stages in series and centralized liquid supply.

Item	Configuration
Equipment model	CVF-1000 (1,000 kg/batch capacity tier)
Single-batch processing capacity	1,000 kg/unit (design maximum five carts 60 trays × 20 kg = 1,200 kg)
Processing time per cycle	≤ 20 minutes
Cooling range	90°C → 10°C
Evaporated water volume	6~10%/batch (source file value, including latent heat and sensible heat)
Primary water catcher heat load	220 kW/unit
Secondary water catcher heat load	45 kW/unit
Refrigeration compressor	Hanbell RC-2 screw compressor, cooling capacity 255 kW (@ -10/40°C), input 70 kW
Vacuum pump	Water ring pump 300 m³/h (11 kW) + rotary vane pump 300 m³/h (7.5 kW, one duty one standby)
Primary water capture condensing side	Normal-temperature water, 32/37°C counterflow cooling tower supply
Secondary water capture secondary refrigerant	-5°C CaCl₂ solution (25% concentration, 0°C return liquid)
Vacuum chamber specifications	Volume 6.8 m³ (internal dimensions 1.0 × 3.4 × 2.0 m), 304 stainless steel, double sliding doors
Entire line and control	34 units complete, including central monitoring
Implementation and warranty	18-week implementation plan; 12-month warranty

The system runs a two-stage route: after the material cart is pushed into the vacuum chamber and the door is sealed, the water ring pump first pre-evacuates the chamber to 10 kPa. In this stage, the water vapor volume is large and the temperature is high. The water ring pump is resistant to high temperature and high humidity, so it first carries away most of the water vapor; after the pressure drops, the rotary vane pump is started, and at the same time the cooling water valve of the primary water catcher is opened, so that the primary water catcher first condenses a large amount of water vapor into water using normal-temperature water. When the primary outlet temperature drops below 40°C, it switches to the secondary refrigerant to catch the remaining low-load water vapor, and continues pumping until the material center temperature reaches 10°C.

The benefit of separating the primary and secondary stages is here: the large load in the high-temperature stage is borne by the normal-temperature water stage, which has a large heat exchange area and low water temperature requirements; only the small remaining load in the low-temperature stage is handed to the -5°C secondary refrigerant, and the secondary stage only needs 45 kW of cooling capacity. The entire refrigeration system is configured at 220 kW plus 45 kW, rather than using one large machine to carry all the way from 90°C to 10°C—equipment investment redundancy is smaller, and the operating load better matches the process curve.

The water catcher is the prerequisite for this process. If water vapor is not condensed into water inside the chamber, the pressure cannot be maintained, and the cycle will keep rising; cooling capacity must also be continuously carried out of the equipment by the refrigeration system, otherwise the water catcher itself will become saturated. The task of the vacuum pump here is to remove non-condensable gases and maintain the pressure at the level corresponding to the endpoint temperature. For the complete product and common configurations of food vacuum rapid coolers, see Food Vacuum Rapid Cooler Product Page.

Performance Data

According to the plan configuration, the core indicators of this system on the project side are:

• Single-batch processing capacity: 1,000 kg/unit, design maximum 1,200 kg (five carts 60 trays × 20 kg);
• Processing time per cycle: ≤ 20 minutes;
• Cooling range: 90°C → 10°C;
• Evaporated water volume: 6~10%/batch (source file value, including latent heat and sensible heat);
• Vacuum chamber: 6.8 m³, 304 stainless steel double sliding doors, 34 complete units for the entire machine, including central monitoring.

The entire cooling process is completed inside a sealed vacuum chamber, without contact with outside air. The same batch of material is consistent from start to finish, without relying on manual turning. The chamber uses 304 stainless steel double sliding doors, and material carts enter and exit as complete batches. The operational workload on the production line side is concentrated in the cart entry and exit stage.

Note: This project case card does not separately record the water loss rate indicator or item-by-item measured values of material inlet temperature. The inlet temperature is based on the hot food 90°C recorded in the source file; the ultimate vacuum degree of the vacuum chamber, the water loss rate of a single unit, and the final number of equipment units are subject to the order confirmation document.

Summary

What is truly difficult about hot food rapid cooling is not “bringing the temperature down,” but “bringing every batch down according to rhythm and to the same endpoint.” In a tropical environment with a 28°C wet bulb, 90°C high-temperature inlet material, and the line rhythm of 34 units, any single-stage configuration at any point in the process will lose efficiency. By splitting water capture into two stages—normal-temperature water and -5°C secondary refrigerant—and making liquid supply a centralized plant room, this plan can deliver 1,000 kg of cooked food from 90°C to 10°C within 20 minutes.

If your production line is also queuing up waiting for cooling after hot food output, you can send us the single-batch weight, output temperature, target endpoint temperature, and number of batches per shift, and we will calculate the configuration according to actual working conditions. For similar food factory rapid cooling and origin pre-cooling cases, see our Customer Case Collection; for specific configuration discussions, Contact Us.