As the core equipment of the central air conditioning system, the air conditioning main unit undertakes the important task of providing cold and heat sources, laying the energy foundation for the entire air conditioning system. It is mainly composed of three categories: water chillers, heat pump units and boilers, which together form the "cold and heat sources" of the air conditioning system.
1. Chiller
The chiller is a key refrigeration device in the central air conditioning system, using water as the heat transfer medium and providing chilled water through the refrigeration cycle. According to the cooling method and working principle, it can be classified into the following types:
Water-cooled centrifugal chiller: Suitable for large-scale projects, with a single-unit cooling capacity range of 700 to 4200KW. Its working principle is to achieve the refrigeration cycle through a centrifugal refrigeration compressor, and the condenser cools down by exchanging heat with normal-temperature water. This unit features stable operation, high efficiency and energy conservation, as well as a compact structure. It is suitable for large commercial buildings, data centers, hospitals and other places that require large cooling capacity.
Water-cooled screw chiller: Suitable for medium and large-scale projects, with a single-unit cooling capacity ranging from 150 to 2200KW. It is composed of a screw refrigeration compressor unit, condenser, evaporator, as well as automatic control components and instruments, etc. Its advantages include compact structure, small volume, light weight, small floor space, convenient operation and maintenance, and stable operation. It is often used in hotels, restaurants, light industry, textile, water conservancy and power projects, etc.
Air-cooled screw chiller: Suitable for various commercial and industrial sites, without the need for cooling towers and cooling water pump systems. The condenser is directly cooled by air cooling, eliminating the need for cooling towers, cooling water pumps and cooling water pipeline systems that are essential for water-cooled chiller units. It does not require a dedicated machine room and can be directly installed on the roof or in outdoor Spaces. It has the advantages of anti-corrosion and anti-rust, and adaptability to various outdoor environments. It is suitable for buildings with limited space where cooling towers cannot be installed, as well as commercial buildings, factory workshops, etc. Its cooling capacity ranges from 115kW to 1508kW. The heating capacity range of the heat pump is 129kW to 1689kW.
Steam absorption chiller: It uses thermal energy as the power source, water as the refrigerant, and lithium bromide solution as the absorbent. It uses thermal energy to drive the refrigeration cycle and achieves refrigeration through the absorption-desorption process. There are two types: steam type and hot water type. It is suitable for places with steam heat sources, such as factories and large public buildings.
Direct-fired LiBr absorption chiller: It can cool in summer and heat in winter, but its application is limited to areas with natural gas. The refrigeration is absorption type and requires natural gas. The difference from the steam type is that it has an additional set of gas equipment. It is suitable for commercial buildings, hotels, hospitals, etc. with natural gas supply.
2. Heat pump unit
A heat pump unit is a mechanical device that forces heat to flow from a low-temperature body to a high-temperature body through reverse circulation. It only consumes a small amount of reverse circulation net work to obtain a large amount of heat supply.
Air-cooled screw heat pump units: They can both cool and heat, but their COP (Coefficient of Performance) is relatively low and they are expensive. The cooling/heating mode switching is achieved through a four-way directional control valve, making it suitable for places that require year-round cooling and heating supply.
Ground source heat pump: It uses the thermal energy of the underground constant-temperature layer as the heat source and exchanges heat with the soil through the underground buried pipe system. It features high energy efficiency, stable operation, environmental protection and energy conservation. It is suitable for new buildings and places with sufficient land area for underground pipe laying systems.
Declaration: The content and template of this article are compiled from the Internet and the copyright belongs to the original author. If there is any infringement, please inform us in time and contact us for deletion.





