Commonly used heat and humidity treatment solutions for clean rooms

Commonly used heat and moisture treatment solutions are as follows：

1、Heating program

Using air heaters to pass hot water or steam into the air heater, you can achieve the air and other wet heating process, air heaters are usually used for primary and secondary heating of air conditioning systems, which can provide a larger supply of heat and is more economical.

The use of electric heaters is to let the electric current heat up the air through the resistance wire. Electric heaters have the advantages of uniform heating, stable heat, high efficiency, compact structure and easy control. Therefore, it is widely used in air conditioning units and small air conditioning systems. In the large air conditioning system and purification air conditioning system with high requirements for constant temperature accuracy, electric heaters are also often used on the air supply branch to control local heating, which is the so-called third heating or called fine heating. However, the use of electric heaters to consume more electrical energy, so it is not appropriate to use in places with large heating requirements.

2、Humidification program

Humidification of the air using an ordinary steam jet pipe. An ordinary steam nozzle consists of a pipe slightly thicker than the steam supply pipe, with a number of small holes of 2—3mm in diameter. Steam in the pipe network under pressure, from these small holes sprayed, mixed to the air flowing from around the steam pipe, so that the air is humidified. Although the ordinary steam pipe structure is simple and easy to process, but the sprayed steam often entrapped condensation droplets, affecting the control of humidification effect. It is usually used in systems with less stringent humidity requirements.

The use of dry steam humidifier to humidify the air. Dry steam humidifier is a steam insulation jacket outside the nozzle, in the insulation jacket through the high-pressure steam, thus ensuring that the outer wall of the nozzle has a high temperature, not to produce condensation in the tube. The steam then passes through the humidifier, the simplified, the inflow box, the inflow pipe and the simplified humidifier, and finally the dry steam is sprayed through the nozzle to humidify the surrounding air. Usually used in large air conditioning systems.

The electric energy in the electric humidifier is used to generate steam, and the steam is mixed directly into the air for humidification without the delivery of pipes. Electric humidifier can be divided into two types, electric heating type and electrode type, according to different working principles. Electrode humidifier is compact and easy to control the amount of humidification, so it is used more. The disadvantage is that it consumes a lot of electricity, and the electrode is easy to accumulate scale and corrosion. Therefore, it is suitable for use in small air conditioning systems. At present, the overall air conditioning unit mostly uses the electrode humidifier, and with the compressor, evaporator, condenser, fan, etc. assembled together in a box, easy to use. Use the method of spraying circulating water to humidify the air. In the drenching room and drenching table cooling section, are equipped with a spray pump, winter spray pool of circulating water, you can achieve the humidification of the air. This method handles a larger air volume, less power consumption, easy to ensure the humidity, is often used in the centralized air conditioning system humidification method.

3、Cooling and drying program

The use of chilled water below the dew point temperature of the air in the drenching room is directly sprayed on the air to be treated, so that heat and moisture exchange can be achieved for the cooling and drying of air. This is the most common method used in air conditioning.

The following are the advantages of treating air in a shower room：

With the diversity of thermal performance, it can be used for enthalpy, temperature and humidity reduction, and can be used to increase baking, temperature and humidity, and can maintain a strict relative humidity in different seasons. When the water spraying temperature is different, the drenching room can do different processes of thermal treatment of air.

The equipment is relatively easy to manufacture, and can be processed on site, or manufactured by professional chemical plants and assembled on site; the metal consumption is less, and the cost is lower; it can also be used for air purification, removing dust in the air, making the air fresh and improving working conditions.

The following disadvantages are associated with the treatment of air in the shower room：

The equipment covers a large area, two rows of horizontal shower room minimum length of 1.9m, three rows of minimum length of 2.5m, while the length of the table cooler is generally no more than 0.6m, shower table cooler is only 1.4m. water system is more complex, in order to adapt to changes in outdoor weather conditions, the general method of changing the temperature of the spray water regulation, that is, the use of part of the circulating water. Therefore, each set of air conditioners must be set up pump; on the other hand, the water system for the open system, no pressure back to the water, such as back to the water can not flow out by gravity or do it, it is necessary to set up a return tank or back to the pump; water and direct contact with the air, susceptible to pollution and dirty, need to regularly drain and replenish new water.

Using chilled water surface coolers to treat air so that heat and moisture exchange is produced, cooling and drying of the air can be achieved. This is also a commonly used method in air conditioning.

The cold water meter cooler has similar air handling capacity compared to the shower room, and its advantages are as follows：

a. Small size of the equipment, small room area required, easy to install；

b. The water system is relatively simple, because the water cycle can be closed system, you can eliminate the cold water tank and return tank and water jet pump; water and air are not in direct contact, to avoid the mutual pollution of air and water, the water system to greatly reduce the amount of water；

c. Low power consumption of the water delivery system, each set of air conditioner table cooler, no need to set up a pump, the resistance loss of the table cooler all by the power station refrigeration feed pump burden, despite the larger air resistance of the table cooler, but the total power consumption of handling air is generally low.

Cold water meter coolers have the following disadvantages in handling air：

The treatment process of the air is not as diverse as the shower room, can only achieve enthalpy reduction (i.e., wet cooling), enthalpy reduction and other wet (i.e., dry cooling) and a part of the increase in baking warming (i.e., heating) three kinds of treatment process, the need for humidification, you must also set up another humidifier, it is not easy to achieve the more stringent relative humidity requirements, which is the biggest drawback of the table cooler to deal with air.

Equipment manufacturing process is complex, can not be processed on site, only by the professional factory production, on-site assembly; metal consumption, generally consume more non-ferrous metals; cost is also higher than the shower room, 10000 & mdash; 160000m3 / h eight specifications of the table cooler compared with the cost of three rows of shower room, an average of more than 30% higher. No dust removal, deodorization effect.

In order to eliminate the above-mentioned disadvantages and increase the efficiency of heat exchange, a surface cooler with drenching water can also be used.

Table cooler with drenching water, drenching water is only used for humidification and dust removal. Its processing function can be the same as the drenching room, suitable for the requirements of the closed chilled water system, and the relative humidity requirements are strict and can not be humidified with steam or steam humidification is not reasonable (for example, no steam source or can not supply steam throughout the day). The use of direct evaporative table cooler can also be processed to achieve the cooling and drying of the air, which is a small air conditioning unit used in the past.

Direct evaporative type because of the use of refrigeration system evaporator as air cooler, so the equipment is simple, small volume, small footprint, the initial investment is also the most economical; but the pipeline loss of refrigerant, requiring strict sealing, so the evaporator and freezer distance should not be pulled far away, generally a freezer evaporator supply an air supply system, the composition of the overall unit. Direct evaporative table cooler is not easy to adjust, not easy to maintain a strict relative humidity, generally used in systems without strict requirements for relative humidity.