The difference between traditional central air conditioning system and multi-connected central air conditioning

1、screw unit central air-conditioning system

The core of the screw unit is the use of screw compressor. The compressor is a rotary type volumetric gas compressor, can be in the low evaporating temperature or high compression ratio can be single-stage compression, through the slide valve device, so that the refrigeration capacity can be adjusted in the range of 10% to 100%. Screw unit COP value is higher, but through the water carrier to the customer end, there is a certain amount of cold loss, and can only be realized in a single cold, heating also need to additionally configure the boiler and other heating devices.

2、Air-cooled heat pump centralized central air-conditioning system

The conveying medium of air-cooled heat pump unit is usually water solution. It produces air conditioning cold/hot water through the outdoor host, which is transported to the indoor end devices by the piping system; the cold/hot water is exchanged with the indoor air at the end devices to produce cold/hot air, thus eliminating the cold/hot load in the room. It is a type of air conditioning system that centralizes the generation of cold/heat but decentralizes the handling of the load in each room.

The indoor end device of this system is usually a fan coil. The fan coiler can generally adjust its fan speed (or adjust the amount of water passing through the coiler through a bypass valve) to regulate the amount of cold/heat delivered to the room, so the system can be individually adjusted for each air-conditioned room to meet the different air-conditioning needs of each room, and its energy-saving properties are also better. However, the hot and cold water distribution system occupies a certain installation space.

3、Multi-connected air conditioning unit

The working principle is: the control system collects indoor comfort parameters, outdoor environmental parameters and state parameters that characterize the operation of the refrigeration system, according to the system operation optimization guidelines and human comfort guidelines, through frequency conversion and other means of regulating the compressor gas delivery, and control of air-conditioning systems, fans, expansion valves and other controllable components, to ensure indoor environmental comfort, and to make air-conditioning system work stably in the best working condition. The air-conditioning system can be operated in the best working condition.

Multi-connected air-conditioning system is a high-efficiency refrigerant air-conditioning system that meets the requirements of indoor hot and cold loads at the right time by controlling the refrigerant circulation volume of the compressor and the refrigerant flow rate into the indoor heat exchanger in the air-conditioning system.

Multi-connected air-conditioning system needs to use frequency conversion compressor, multi-pole compressor, unloading compressor or a combination of multiple compressors to realize the compressor capacity control; in the refrigeration system needs to be set up electronic expansion valve or other auxiliary circuits to regulate the refrigerant flow rate into the indoor machine; through the control of indoor and outdoor heat exchanger fan speed product, the capacity of the heat exchanger is regulated.

Inverter speed control and electronic expansion valve technology is gradually mature, inverter multi-connected air conditioning system commonly used inverter compressor and electronic expansion valve. The air conditioning system works under the condition that the ambient temperature and indoor load are constantly changing, and the system components and the system environment and the environment each other, so the state of the multi-connected air conditioning system is constantly changing, and it is necessary to regulate the capacity of the air conditioning system at the right time through its control system, and to eliminate the effect is a flexible regulation system.

Results: screw units and air-cooled heat pumps through the secondary carrier water for the transmission of cold and heat, cold and heat will have a certain loss, while the multi-unit is directly through the refrigerant for cold and heat exchange, no secondary carrier, more energy efficient