Freeze-drying method is frequently used to preserve perishable products, extend their shelf life or make them ready for export. When using freeze drying, the material is frozen first. Then the pressure is reduced and heat is added to turn the frozen water into steam (sublimation). However, attention should be paid to energy consumption in the drying process.
The freeze-drying technique is frequently used, especially in the food and pharmaceutical industry. A wide variety of foods, from ready meals to fruits or snacks in the markets in daily life, are produced with this technique. In this way, food preserves its freshness and nutritional value. So, how is the energy used in this technique?
Energy consumption during the freeze-drying process cannot be prevented. Although this technique is advantageous and economical, the energy consumed during the realisation of the aforementioned process is extremely high. However, considering that the shelf life of the foods in which freeze-drying is used will be long, it can be said that it is economical even if the energy consumption is high.
Thanks to the freeze dryers, among the latest technology products, you can preserve your food as it was on the first day. “Why should I use freeze-dry?” The answer to the question is quite simple. Because thanks to these machines, you can store and use your food for up to 25 years without any changes.
Things to Know About Energy Consumption in the Food Industry
There are many methods used to protect products in the food industry. When these methods are used to dry foods, extend their shelf life, and make them healthier and more durable, a high amount of energy consumption may occur. Although freeze-drying machines are handy for the food industry, it is also known that they consume more energy than many technological tools.
Some methods can be used to reduce energy consumption in the food industry. Thanks to these, foods can be made ready for consumption economically and economically. Some of these methods are:
Automate, Monitor and Control
By setting specific energy targets in the food sector, energy consumption in different business areas can be reduced. A robust control process can be achieved by monitoring the kilowatt consumption to optimise equipment utilisation. In addition, making operators and facility managers more aware of this issue can also help reduce energy consumption.
Making Cooling and Temperature Controlled Systems More Efficient
Cooling and heating account for about 30 to 80% of energy consumption. Using more efficient heat exchangers or high-efficiency cooling systems in this area makes it possible to save money.
Using Variable Speed Drives and Motors
Using variable speed drives for electrically powered equipment can save up to 50% in energy consumption.
Using Energy-Saving Lighting Systems
LED lights that consume the least energy can be used in the food industry to save money. With this system, which requires less maintenance, both more efficient results can be obtained, and costs can be reduced.
By using these and similar simple methods, energy consumption in the food sector can be reduced to a minimum. These methods can also be preferred for freeze drying, which is frequently used in the food industry, especially recently. Thus, it is possible to carry out the process much more economically.
How Much Energy Does Freeze Drying Consume?
Freeze-drying devices; refrigerators, freezers, dishwashers and other household appliances also need more electricity. However, although energy consumption is high, freeze-dried food is much more durable and long-lasting on the shelf. Therefore, when all food storage capacity and time are considered, the total cost is considerably reduced.
Freeze-drying machines have been used frequently recently and greatly benefit the food industry. In addition, it consumes energy according to the area in which it is used. To have information about the energy consumption of the machines in question, you can take a look at the list below.
- A freeze dryer used in a small or medium household consumes approximately 990 to 1500 watts per hour.
- Depending on the local electricity costs of the region in which it is used, the cost of the freeze-drying process varies.
- A medium sized freeze dryer uses approximately 30 kilowatts of electricity per load.
Another important issue here is that the products to be put into the machine should be manageable. The more weight put into the machine, the longer the drying time will be. Therefore, cutting food into small pieces and slicing it thinly to minimise drying time will save energy.
Relationship Between Time of Freeze Drying Process and Energy Consumption
The machines preferred for freeze-drying consume energy in direct proportion to the time they are used. Freeze dryers do not dry the related products in one step. For products that go through 4 different stages, the machine provides a different time for each of them. You can check the list below for the mentioned stages, time spent and energy consumption.
- The shortest stage of freeze drying is freezing. The freezing process takes about 1 hour, depending on the amount of product, and approximately 56 kWh of energy is consumed in 1 hour.
- The second stage is drying. The drying process is completed in approximately 9 hours, and the machine uses 3.6 kWh of energy.
- The third stage is the final drying. This process takes about 33 hours and consumes approximately 20.1 kWh of energy.
- The final stage is the full cycle. Here, 47 hours of operation are made, and approximately 29.9 kWh is consumed.
The values above may vary depending on the amount loaded into the machine. The more nutrients loaded into the machine, the longer the drying process will take. Therefore, energy consumption also increases at the same rate. For example, if an average machine runs for 47 hours, approximately 1414 watts of electricity is consumed per load.
If you want to know how much electricity the freeze-dryer consumes, you can use an electricity meter. After installing this tool in the machine, you can have information about the consumption of watts, amps, hertz, kilowatt-hours and volts while the freeze dryer is running.
You can reach our previous article from https://liyolife.com/en/freeze-dry-and-cold-chain/