Heat transfer in case of direct product cooling
In view of the specific needs and expectations of our customers in the field of heat transfer in the case of direct product cooling, we provide the calculations on one hand and the manufactured technical systems and components on the other hand. Consequently, both are tailored to functionality and efficiency, but also never to lose sight of process stability of the respective field of application. Our ice water systems, falling film chillers, ice banks or heat exchange systems have this stability to ensure that the cooling process chain is not interrupted.
Ice water with temperatures of 0.5°C can perform very well for direct product cooling
of large quantities of product in a very short time and has therefore been used for many years in food cooling and process cooling wordwide. Ice water slightly over 0°C has no risk of freezer burn and is ideal for direct product cooling as such in most of the applications.
Many customers are critical about the use of ice water due to too moisture, but they forget, that fruits and vegetables are resistant to rain by nature. Fish and seafood are naturally under water.
Furthermore, the overall product is a combination of the heat transfer calculation of the final product and the calculation of the economics of these heat exchangers (author is head of our R&D department). Both are therefore prior components of the overall system, which are not negligible.
In addition, we calculate the necessary quantities of water or ice in the case of direct product cooling. However, the components of ice water (0.5 ° C) and / or chip ice (-0.5 ° C) are of primary importance to us in this heat transfer calculation. In cases where ice water (0.5 ° C) is insufficient for the cooling process, mainly in the meat industry and the fish processing, ice (-0.5 ° C) must be used.
Energy consumption advantage of a BUCO Industrial Ice machine
To produce ice, we do have the efficiency in prior focus. Only by melting of the ice, the heat for cooling of the water is taken from the surrounding. Ice is melting at a temperature of 0°C to water and gives 335 kj per kg ice. Therefor we do produce ice with an evaporation temperature T0= -10°C, which generates ice at a temperatures of T= -0.5°C to -1.0°C. The idea is simple, as the cooling gain for subcooling of the Flake Ice in conventional drum systems is down to T= –8°C, which is only approx. 8% of a higher melting capacity. Unfortunately this has a high energy consumption impact for the drum ice machines as such:
Energy cost comparison of a BUCO Industrial Ice machine
and a conventional drum system
Example: 30 to ice / day
Necessary refrigeration power including losses: ca. 150 kWref
Electric power for the drive of the refrigeration machine:
-30 / 35 °C with COP = 1,8 Pel = 84 kWel -Drum system –Flake Ice
-10 / 35 °C with COP = 3,6Pel = 42 kWel -BUCO Ice Pack
Additional drives: 6 kW
Price for electricity: 0,15 €/kWhel
Running costs at -30 °C : 324 €/day or 11 €/to ice -Drum system
Running costs at -10 °C : 173 €/day or 6 €/to ice -BUCO Ice Pack
Savings: 151 €/ day
for 300 days production: 45.300,-€/ year savings of electricity costs
The manufactured products that generate this are basically the falling film chiller (ice water 0.5 ° C) and the industrial ice maker (plate ice -0.5 ° C) to serve the following products of industrial food refrigeration:
- Fish, meat, poultry
- Fruit Vegetable
- Milk, milk products
- beverage production
- Bakery production
Or find use in cooling processes in the production of:
As in the use of:
- Heat pumps at lowest water temperatures