Cooling system installation for cooling rooms made for kiwi preservation in Asturias.
The project, which completed its first phase successfully, is made up of 4 rooms, each measuring 1,000m3 and capable of storing 3,600 bins, which is more than 1,250,000 kg of kiwi.
In the second phase of the project, the company is planning to increase its storage capacity by about 50%.
ISOFRED created a vapor mechanical compression circuit and direct expansion of the HFC R-134-a coolant with air condensation and forced convection evaporators. In the fruit-preserving cooling rooms, they are expecting to use cubic-type evaporators with specific designs to use the bins to their full capacity. In addition, each of the bins has a streamer or air-flow concentrator to extend their power (maximum air force distance).
The project, with the help of a humidifying system is able to maintain a relative humidity very close to 95%.
The HFC coolants are in an initial vanishing phase due to the establishment of the European F-GAS Rule that will be complete in 2030, when it will no longer be possible to manufacture many of them. Furthermore, the introduction of taxes on fluoride gases (RD260/2.013), which economically penalizes the use of these types of coolants on projects in which one needs to replace systems that have leakages or broken tubing, has revolutionized the cooling gas manufacturers. This has led to extreme designs that don’t benefit the client at all as far as energetic efficiency and investment amortization is concerned.
For this project, they rejected the use of natural alternatives to HFC, like waterless ammonium as a direct coolant, and also indirect coolants with water and glycol that has previously been cooled with an ammonium system. They are considered inappropriate for their high initial investment cost and the associated working energy in the case of the indirect coolants.
Moreover, we’ve been able to reduce the amount of HFC in the installation through a type of condenser that is micro-canal, and with a low coolant load, which has achieved a coolant gas reduction of more than 70% in the equipment with respect to the standard system.
Coolant used for Designed System
The coolant that was chosen for this system is the R-134-a because its functioning characteristics give it the appropriate ability for this particular system. Some of the main advantages of this coolant is that it doesn’t harm the ozone layer and that it has a low to moderate heating power (PCA = 1,300). In addition, it is very safe, it is not flammable, and it is miscible with POE and pure oils, which means there is no sliding or gliding in its functioning. Its working pressures and temperatures are low-moderate, which minimizes risks of leaking and it promotes maximum working mechanical reliability for being such moderate working conditions. All of this is included, along with ratios of cooling power versus consumed electric power or considerable COP of 3.53 in working conditions.
Cooling System Description
- Vapor mechanical compression circuit with R-134-a coolant, with continuous VIRTUALLY STEPLESS capacity regulation between 10 and 100%. In this way, it adjusts electric consumption to the needs of the cooling system.
- Floating condensation through air and compact interchanging condensers, which helps maximize savings and reduces electric consumption.
- Level of electric liquid with change detection in the entire system. This includes an automatic sectioning function in case of a coolant leakage.
- Large surface evaporators designed to optimize fruit preservation, wide ventilation piece and streamer for a better air flow.
- Circuit defrosting filtering system with a scheduled self-cleaning function with flow reversal and automatic clearing/purging element.
- Complete electrical panel with differential and thermal-magnetic protection in all cooling elements.
- Personalized control and management of system through an open-code SIEMENS PLC with remote access via Ethernet, safe for remote maintenance. SCADA touchscreen that’s easy-to-use in the workplace.