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VRF systems and chillers, especially mini-chillers, sometimes make it difficult for consumers to make choices. In this article, the advantages of VRF system over mini chiller are examined:
Lower power consumption
VRF power consumption is extremely lower than mini-chillers and has a higher performance factor than mini-chillers, due to the presence of compressors equipped with advanced electronic boards in the fan and compressors in outdoor units that vary the compressor speed from 1HZ to 120HZ. In proportion to each device and the set temperature, the average refrigeration value of the compressor and electronic expansion valves will be provided. The power distribution will be unified and even when a compressor fan coil is turned on, it will work at its maximum power and even the compressor fans (condenser fan).
Suitable temperature range
VRF systems work up to + 56 ° C in summer and -20 ° C in winter and have no capacity reduction up to +43 ° C, while in mini chillers such as +35 ° C They have their maximum capacity or 100% according to the standard, so with the increase of air temperature from +35 upwards, the capacity of the mini-chiller is drastically reduced and a device with a higher capacity should be selected to cover the above issue.
Device noise
The volume generated by VRF (indoor and outdoor units) will be much lower than the mini chiller, and even with these characteristics, the static pressure of VRF fans can be reduced in proportion to the space, which again in indoor and outdoor units. It will drastically reduce the level of sound produced.
Air distribution and control system
The indoor units of VRF system (built-in ceiling) are equipped with a static pressure change system inside the fans, which can easily control the air distribution system inside the spaces and the intensity of air launch in addition to the three cycles in the thermostat can be adjusted or increased or decreased. Dad. If the air balancing system is not available in the fan coil.
Problems due to fluid leakage
Inside the copper pipes, due to the presence of refrigerant, there will be no damage to the roof and… .. in case of leakage, it can be easily found, although the issue of gas leakage is very rare, while in mini-chiller systems There is often the possibility of water leakage from the hoses connecting the chiller piping to the fan coil or drain, which, if created, will cause dampness and moisture in the roof and yellowing of the surfaces.
The cost of acid washing
Fan coils The connection to the mini-chiller must be acid-washed every year due to sediment in the water system, which imposes a high cost on the project and also reduces the life of the fan coil system. In the absence of acid washing, the heating and cooling efficiency of the fan coils will be drastically reduced.
Specialized maintenance costs
Chiller systems + mini chiller + fan coil in each start-up season should consider a technician to ventilate and spray the circulation pump, also the water in the circuit should be drained by a professional technician at the end of each season and if not Drainage of water (because the evaporator transducer is a plate type) will cause the transducer to burst in the winter, which will incur significant costs for the operator or end consumer.
professional repair services
Another problem of the mini chiller is the lack of proper access to the circulation pump, match sensor and flow sensor, which must be opened to access the chiller door in each season and they must be replaced or repaired.
Restrictions on plumbing
Another problem of mini-chillers is the limitation during the piping of chiller water in vertical and horizontal position, for example, for a mini-chiller, 5 tons of coldness is equal to 30 meters. In this project, only third and fourth floor mini-chillers can be installed on the roof. The contract and the rest of the mini-chillers have to be installed on the terrace due to the above limitation, and if the above issue is not considered in the mini-chillers, usually the end-of-season fan coils will have a lot of cooling problems.
Lack of proper water supply
Another problem of the mini-chiller is the lack of proper water supply in the chiller circuit by the pump in the chiller, which if the auxiliary pump is not used, the flow-related error will appear and the system will turn off.
Other common problems
Other problems of mini-chillers include lack of proper protection in the compressor such as inlet and outlet temperature of the compressor (to adjust the superheat and subcool), oil temperature and oil level, suction and discharge pressures, checking the phase sequence to reverse the compressor, flow sensors Etc. It may be a problem due to the slightest power fluctuation and even the compressors will fail very quickly, or due to the reverse operation of the compressor, serious damage will be done to the compressor and out of the circuit, or even due to lack of superheat control and Liquid subcoal enters the compressor, causing the compressor to burn.
Also, there is no control over the oil level and oil temperature, which if the oil does not return or the compressor temperature rises, which will lead to high temperature in the oil and reduce the viscosity of the oil, which will cause the compressor to burn.
