The types of high-precision constant temperature and humidity air conditioners mainly include air-cooled, water-cooled, chilled water, dual-cold source and natural cooling.
Today, we will mainly start from their principles, structural composition, advantages and disadvantages, and make a simple sorting of them, so that users who are interested in this content can quickly understand the similarities and differences between them, lay a good foundation and then have a deeper understanding.
1. Air-cooled high-precision constant temperature and humidity air conditioner
The heat absorbed by the air-cooled unit from the machine room is transferred to the outdoor air through the condenser (precision air conditioner outdoor unit) installed outdoors or on the roof.
The composition is simple, consisting of an indoor unit and an outdoor unit. The indoor unit contains a compressor, evaporator and expansion valve, and the outdoor unit is a condenser. The indoor unit and the outdoor unit form a closed loop.
Principle of air-cooled high-precision constant temperature and humidity air conditioner
Advantages: simple and reliable system, easy maintenance, high reliability, low overall investment cost
Disadvantages: outdoor unit has high noise, limited installation distance, and low cooling efficiency
Air-cooled high-precision constant temperature and humidity air conditioner is currently the most widely used type in data centers, suitable for areas with water shortages and places lacking cooling water systems.
2. Water-cooled high-precision constant temperature and humidity air conditioning
The heat absorbed by the water-cooled unit from the machine room is transferred to the refrigerant through the built-in water-cooled condenser.
The main difference from the air-cooled unit is that the water-cooled unit is equipped with a plate condenser in the indoor unit, and the internal circulation of the refrigerant is only in the indoor unit, and an external cooling tower is required.
Cooling water usually uses a mixture of antifreeze water and ethylene glycol instead of the commonly used refrigerant.
Principle of water-cooled high-precision constant temperature and humidity air conditioner
Advantages: higher energy efficiency than air-cooled units, more energy-saving
Disadvantages: higher initial investment and maintenance costs
Water-cooled high-precision constant temperature and humidity air conditioners are suitable for places with centralized cooling water systems.
3. Chilled water type high precision constant temperature and humidity air conditioner
The chilled water type high-precision constant temperature and humidity air conditioner controls the ambient temperature in the machine room through chilled water. The premise is that there must be chilled water. The chilled water of the central air conditioner can be used, or a new chilled water system can be built.
It consists of a chiller (air-cooled chilled water unit, water-cooled chilled water unit), an air-cooled condenser, and a cooling tower.
The chiller is equivalent to an outdoor unit, which includes four main components: a compressor, an evaporator, a condenser, and an expansion valve, thereby achieving the cooling and heating effect of the unit.
The indoor unit of the chilled water type machine room precision air conditioner is mainly composed of a chilled water coil, a fan, an electric heater, a humidifier, and a water valve, and generally no compression refrigeration system is set.
Principle of chilled water type high-precision constant temperature and humidity air conditioner
Advantages: small initial investment
Disadvantages: over-reliance on chilled water
Chilled water type high-precision constant temperature and humidity air conditioner is suitable for areas with abundant water resources or places with abundant chilled water systems.
4. Dual cold source high-precision constant temperature and humidity air conditioning
The dual-cold source type high-precision constant temperature and humidity air conditioner is a dual system with independent chilled water units and direct expansion refrigeration systems. There are two combinations:
① Air-cooled condensation + chilled water, with the chilled water system as the main system and the air-cooled system as the backup
② Water-cooled condensation + chilled water, with the chilled water system as the main system and the water-cooled system as the backup
The unit will give priority to using the chilled water system for cooling in places where chilled water resources can be provided but cannot be guaranteed to be continuously supplied throughout the year; when the chilled water supply is interrupted or the chilled water temperature is not enough to bear all the load requirements, the direct expansion refrigeration system will be automatically started.
Principle of dual-cold source type high-precision constant temperature and humidity air conditioner
Advantages: Dual systems backup each other, high reliability, good energy-saving effect
Disadvantages: More parts, high initial investment cost, little advantage
Dual-cold source type high-precision constant temperature and humidity air conditioners are mostly used in large and medium-sized exchange rooms and mobile computer rooms, and are also widely used in computer rooms and telecommunications rooms (IDC).
5. Natural cooling type high-precision constant temperature and humidity air conditioningIt is a type of water-cooled air conditioning system, which mainly uses ordinary ethylene glycol refrigeration system for cooling. It consists of indoor units, outdoor units, and ethylene glycol solution.
When the outdoor temperature is lower than the set value, ethylene glycol refrigerant can directly and freely cool for energy saving.
At this time, ethylene glycol circulates in the refrigeration pipe, and the refrigerant circuit and ethylene glycol circuit are cooled at the same time, which can reduce the energy consumption of the compression refrigeration system. The system has two working modes, partial natural cooling mode and full natural cooling mode.
Ethylene glycol natural cooling type precision air conditioner is installed with dry cooling tower outdoors, which is similar to the outdoor unit of air-cooled air conditioning system, but the material in the pipe is different, the former is hot water, and the latter is high-temperature condensing agent.
Ethylene glycol natural cooling type precision air conditioner
Advantages: Refrigeration efficiency is higher than air cooling, energy saving and emission reduction
Disadvantages: It cannot be used in real time and has requirements for outdoor temperature
Natural cooling type precision air conditioner is suitable for all-year cooling areas in the north, energy-saving transformation of Internet IDC computer room, etc.
The high-precision constant temperature and humidity air conditioners introduced above have their own strengths in corresponding cooling methods. Users need to make comprehensive considerations based on their own needs and relevant environmental conditions to choose the best solution for themselves.