With the improvement of people's living standards, people's requirements for comfort are getting higher and higher. The popularity of central air conditioning in office buildings, hotels, and family homes has increased significantly. Among them, the type of air-conditioning units has also developed from a single air source heat pump to a water source heat pump, a ground source heat pump, a constant temperature and humidity air conditioner, and a precision air conditioner. During the use season of the air-conditioning unit, 40% to 50% of the electricity consumption in the building is consumed by the air-conditioning system. How to make the air-conditioning system more energy-efficient on the basis of ensuring the control accuracy of the air-conditioning system has become the focus of current air-conditioning industry research. At present, the main air-conditioning units include air source heat pump units, water source heat pump units, ground source heat pump units, constant temperature and humidity units, lithium bromide units, etc. The compressors used are mainly screw type, scroll type, piston type, and centrifugal compressors.Air source heat pumps are also called modular units. Generally speaking, such units are relatively small. In air conditioning projects, multiple units are often connected in parallel to the system. Each unit is like a cooling unit and can be combined according to demand. So it is called a modular unit. 2 个、 4 个压缩机，也有可能根据项目的特殊需求包括更多的压缩机。 There are many scroll compressors used in this type of unit. One unit can include two or four compressors. It is also possible to include more compressors according to the special needs of the project. The process logic of this type of unit is relatively similar, usually including cooling, heating, timing start-up, fault handling and other functions. At present, compressors are usually adjusted using second-order fuzzy adjustment for loading and unloading.
Water source heat pumps perform heat exchange through groundwater or surface river water, and ground source heat pump units perform heat exchange through soil. These two types of units use the characteristics of constant temperature of groundwater and soil in winter and summer to assist the unit's heat exchange. The heat exchange efficiency is high and does not affect the surrounding environment. Such units often use screw or scroll compressors, and the owner may include multiple fluorine and water channels as required. The system also includes a circulating water pump. During the transition season, the water pump needs to be inspected regularly to avoid damage to the water pump if it is not used for a long time.
Constant temperature and humidity air-conditioning applications and occasions with high requirements for comfort generally include temperature adjustment and fresh air processing. The temperature and humidity can be adjusted through the cooperation of the compressor and the humidifier. The structure of the constant temperature and humidity air-conditioning unit mainly includes an integrated air-conditioning unit and a combined air-conditioning unit. The combined air-conditioning unit uses the structure of an indoor unit and an outdoor unit. However, higher requirements are also put on the controller and control strategy. The indoor unit and the outdoor unit use communication to achieve mutual coordination to complete the adjustment of indoor temperature and humidity.
并且对空调机组的控制工艺以及节能算法有着很深入的研究。 Hollysys can provide perfect solutions for air source heat pumps, water source heat pumps, ground source heat pumps, constant temperature and humidity, and lithium bromide units, and has in-depth research on the control process and energy saving algorithms of air conditioning units. For the air-conditioning room system including multiple heat pump units, the cooperative control idea and advanced scheduling algorithm are used to improve the efficiency of the unit's circulating waterway, and each compressor can work at the optimal and suboptimal operating point, thereby achieving energy-saving control. Rich communication interfaces and convenient communication methods also make it easier for unit monitoring and multi-unit coordination. The PLC module can also do three-proof processing in order to adapt to the harsh working environment.
The picture shows an air-conditioning room control system. This system is divided into three layers. The bottom layer is the equipment layer, which includes compressors, inverters, valves, and fans. PLC 与触摸屏， PLC 进行各自空调主机的控制以及保护工作，触摸屏上可以进行机组的厂家参数、用户参数设置，机组操作，运行工况监视等工作。 The control layer in the middle includes PLC and touch screen. The PLC controls and protects the air-conditioning host. The touch screen can be used to set factory parameters, user parameter settings, unit operation, and operating condition monitoring of the unit. RS485 连接到空调机房的机组上。 At the top is the management layer, which is used to monitor and record the operating status of each unit and operate the unit. The upper unit can be connected to the unit in the air-conditioning room through Ethernet or RS485 .
LM 系列 PLC 可以为多种中央空调机组提供解决方案。 After years of research and technology accumulation in the central air-conditioning industry, Hollysys LM series PLC can provide solutions for a variety of central air-conditioning units. The units involved include air source heat pump, water source heat pump, ground source heat pump, constant temperature and humidity air conditioner, precision air conditioner, lithium bromide unit and so on. Based on the idea of creating more added value for customers, we have thoroughly studied the process requirements of central air-conditioning equipment, and have continuously improved the functions of the system. We are committed to ensuring the accuracy of air-conditioning units while making the system more energy-efficient and reliable. While bringing powerful air-conditioning systems to customers, it also makes customers' production and maintenance more efficient and convenient. “ 安全、可靠、节能 ” 的理念。 The perfect solution implements the concept of " safety, reliability and energy saving " .
在中央空调行业具有下述 6 大优势。 LM PLC has the following six advantages in the central air-conditioning industry .
Intelligent temperature acquisition module
系列 PLC 包括丰富的温度采集模块，不仅具有 4 点、 8 点的点密度，而且所有模块均为智能型，在传感器出现故障或断线时 LM 会立即对机组执行保护动作。 The LM series PLC includes abundant temperature acquisition modules, which not only have point density of 4 points and 8 points, but also all modules are intelligent. When the sensor fails or is disconnected, LM will immediately perform protection actions on the unit.
三防 ” 模块 " Three defenses " module
具有防湿热、防霉菌、防盐雾的三防模块，即使在恶劣的工作环境下，也能保证机组可靠稳定的运行。 The LM has a three-proof module that is resistant to heat and humidity, mold, and salt spray. It can ensure the reliable and stable operation of the unit even in harsh working environments.
Powerful communication extension function
包括 RS232 、 RS485 、以太网及 DP 接口，可以方便的实现远程监控、机组群控功能。 LM PLC includes RS232 , RS485 , Ethernet and DP interfaces, which can easily realize remote monitoring and unit group control functions.
In-depth control strategy research
Hollysys thoroughly researched the control strategy of the air-conditioning unit, and encapsulated the functions of second-order fuzzy load and load reduction control, compressor protection, and sequential start-stop, which make the system establishment more convenient and faster.
Energy saving algorithm
Hollysys has in-depth research on multi-unit coordinated control. It uses expert algorithms to ensure that each unit works at the optimal and suboptimal operating point, thereby achieving energy-saving control.
Rich project experience
Hollysys has accumulated a lot of experience in air-conditioning unit projects and is very familiar with the unit control. It often puts forward valuable suggestions for customers to ensure that the project is implemented well and quickly.