CN201293409Y - Fresh air handling unit - Google Patents

Abstract

The utility model discloses a fresh air unit, which comprises a fan section, a flow equalization section, a medium-efficiency section and a sub-high-efficiency section, and a surface cooling section, a reheating section and an air supply section. A coarse-effect filter, a frequency conversion motor and a Centrifugal fan, the flow equalization, medium efficiency and sub-high efficiency sections are provided with a flow equalizer, a medium-efficiency filter and a sub-high-efficiency filter in sequence, and it is characterized in that: the surface cooling, reheating and air supply sections are respectively set There are water-cooling coils and direct evaporative coils, the water-cooling coils are provided with water inlet and outlet pipe interfaces, and the direct evaporative coils are provided with refrigerant inlet and outlet interfaces. The utility model improves the energy-saving effect by arranging water cooling coils and direct evaporative coils in the surface cooling, reheating and air supply sections, and conveniently and effectively solves the problem of temperature and humidity control in key departments of the hospital.

Description

A fresh air unit

technical field

The utility model relates to an air treatment system, in particular to a terminal fresh air treatment unit suitable for an air-conditioning water system, mainly suitable for key departments and places where indoor air parameters such as hospital operating rooms need to be precisely controlled.

Background technique

The indoor environment control requirements of hospitals are usually divided into two categories, one is general departments and general wards with a large number of areas, and the usual comfortable air-conditioning can meet the air-conditioning requirements for these areas; the other is a relatively small number of Key departments with sterile control requirements, such as operating rooms, etc., their environment needs to be precisely controlled throughout the year. Large-scale general hospitals in my country usually adopt centralized air-conditioning systems, and the central cold and heat sources of the hospital centrally supply the chilled water and heating hot water required for air-conditioning in various functional departments. The end of the air conditioning system of each functional department usually includes a fresh air unit and a return air unit to meet the indoor temperature and humidity requirements and avoid excessive bacteria and carbon dioxide concentrations. The higher the temperature and humidity control requirements, the more energy consumption, and the higher the requirements for the enclosure structure. Simply put, the high-demand environment is at the cost of high construction and operation costs. Therefore, the operating room, burn ward and other places that are easily infected by bacteria in the air and where the temperature and humidity have a great impact on the wound are set as key departments, and the environmental control requirements are also very high; Departments, air conditioning requirements are only comfort.

Typical hospital air-conditioning system configurations often have the following problems during year-round operation:

(1) In order to ensure the humidity control requirements of a key department, the chilled water outlet temperature is usually set to 7°C (or even lower) under the cooling condition of the air conditioner. In the past, in order to ensure the control of room temperature and humidity in key departments, the traditional primary return air was often used for reheating. Now, in order to save energy, the secondary return air has to be used. Due to the small heat-humidity ratio of these departments, the air-conditioning unit needs to control a lower dew point.

(2) As the outdoor temperature drops during the air-conditioning period, in order to ensure the air-conditioning requirements and energy-saving needs of most general departments, the water temperature of the centralized supply of chilled water is often increased, which objectively causes the humidity of key departments to exceed the standard.

(3) The key departments of large hospitals are usually located in the inner area of the building. When ordinary departments do not need cooling (excessive season) or heating (winter), these key departments still need cooling.

(4) According to the survey, due to various reasons, the chilled water in most hospitals cannot guarantee the water supply temperature of 7°C during the actual operation of the cooling season (sometimes even if it reaches this temperature), and it is difficult to guarantee the room temperature and humidity of key departments.

In order to facilitate the control of the environment of general and key departments of the hospital and improve the energy utilization efficiency of the system, the air-conditioning designers of the hospital now either divide the centralized chilled water supply of the whole hospital into two systems, or separately configure the air-conditioning cold and heat sources for the key departments. However, for existing hospital buildings, using such technology to transform the cooling system will cost too much financial, material, and manpower, and it will take a lot of time. Most hospitals have to sacrifice environmental control to maintain the original status, and cannot meet the temperature and humidity control requirements of key departments in the "Hospital Clean Operation Department Building Technical Specifications" GB50333-2002 [2] (hereinafter referred to as the "Specifications"), as well as the hospital's general departments and key departments. Departments have conflicting demands on chilled water supply temperature.

General departments and key departments of the hospital have different requirements for chilled water supply temperature, because they have different requirements for humidity control. In order to avoid the energy-consuming measures of lowering the chilled water temperature of the entire hospital due to the humidity control of a few key departments, only the fresh air of the key departments should be treated in depth to eliminate the new rheumatic load, and even bear the indoor humidity load to reduce the dehumidification requirements of the original terminal unit. It is possible to make the terminal unit use chilled water with higher water temperature, which should be the simplest and most effective method. This method is to determine the chilled water temperature of the entire hospital air conditioner according to the environmental control requirements of general departments, and the key departments solve indoor temperature and humidity control through advanced fresh air treatment. At present, using the concept of fresh air pretreatment to improve the humidity handling capacity of the original system has achieved certain results in improving indoor air quality. However, the main purpose of fresh air pretreatment is energy-saving transformation, which cannot fully meet the temperature and humidity control requirements of key departments, so there are also shortcomings.

Contents of the invention

The purpose of the utility model is to provide a fresh air unit, through the improvement of the structure, the energy-saving effect is improved, and the temperature and humidity control of key departments can be solved conveniently and effectively.

In order to achieve the above purpose, the technical solution adopted by the utility model is: a fresh air unit, including a fan section, a flow equalization section, a medium-efficiency section and a sub-high-efficiency section, and a surface cooling section, a reheating section, and an air supply section. There are coarse-efficiency filters, frequency conversion motors and centrifugal fans. The flow equalization, medium-efficiency and sub-high-efficiency sections are sequentially equipped with flow-sharing plates, medium-efficiency filters and sub-high-efficiency filters. The surface cooling, reheating and delivery A water-cooling coil and a direct evaporative coil are respectively arranged in the wind section, the water-cooling coil is provided with a water inlet pipe and a water outlet pipe interface, and the direct evaporative coil is provided with a refrigerant inlet and outlet interface.

In the above technical solution, the water-cooled coil is connected to the cold water system of the central air conditioner, and the direct evaporative coil is connected to the peripheral refrigerator to form a complete air-conditioning system.

In the surface cooling, reheating and air supply sections, the position of the water cooling coil and the direct evaporative coil relative to the air supply direction can be changed, that is, the following two setting methods can be adopted: first, the water cooling coil is located in the upper wind end, the direct evaporative coil is located at the downwind end. Second, the direct evaporative coil is located at the upwind end, and the water-cooled coil is located at the downwind end. Among them, the preferred technical solution is that the water-cooled coil is located at the windward end, and the direct evaporative coil is located at the downwind end.

In the above, due to the different humidity control requirements of general departments and key departments of the hospital, the temperature requirements for chilled water supply are also different. Treat to eliminate fresh rheumatic load. Since the fresh air unit is equipped with water-cooled coils and direct evaporative coils, the chilled water of the central air-conditioning system can be used to cool and dehumidify the fresh air, and then the additional direct evaporative coils can be used to dehumidify and cool again. The required dew point of the machine is finally controlled to the required air supply state point by using its own condenser heating, and the excess condensation heat is discharged by the external fan condenser unit.

In summer use, since the fresh air unit is equipped with a water-cooled coil and a direct evaporative coil, firstly control the fresh air to pass through the water-cooled coil and the evaporator for two-stage cooling and dehumidification to reach the required dew point temperature of the machine, eliminate all the humidity load of the system, and then control The heating capacity of the condenser reaches the required air supply temperature, and the excess heat is discharged by the external condenser. The energy consumption of wet cooling such as circulation units is reduced, and chilled water with a higher water temperature can be used to complete the temperature and humidity control of key departments. In winter, key departments are often located in the inner area of the hospital building. The air-conditioning system is switched to heating mode, and the outer area is heated, while the inner area still needs to be cooled. In addition, the operating department needs to be heated before the operation starts. Need to switch to cooling. With this fresh air unit, even though the water coil runs hot water in winter, the direct evaporation coil can still be in a cooling state. The outdoor air is heated and humidified, and the indoor circulation unit also heats the circulating air. When the operation is in progress, the hot water coil is turned off and the direct evaporator coil is turned on to cool the fresh air. The use of direct evaporation coils and condensers can always ensure that the centralized fresh air is stabilized at the required state point. This state point enables the fresh air to eliminate the design heat load in the operating room, and the change in the indoor load is resolved by the reheating of the circulation unit. In the transitional season, since key departments still need heating and cooling, it is only necessary to operate the direct evaporative coil at this time, and adjust the cooling capacity of the evaporator and the heat capacity of the condenser to effectively control the temperature and humidity.

Due to the application of the above-mentioned technical solutions, the utility model has the following advantages compared with the prior art:

1. The utility model combines the chilled water system and the direct expansion system by setting water cooling coils and direct evaporative coils in the surface cooling, reheating and air supply sections. The cooling and dehumidification speed is fast, the structure is compact, and it is easy to control. It improves the operating quality of the fresh air system, conveniently and effectively solves the problem of temperature and humidity control in key departments of the hospital, and reduces the risk of secondary pollution of the circulation unit system.

2. The use of the utility model avoids the large-scale transformation of the original air-conditioning system, improves the working efficiency of the original system, and saves energy.

3. The special fresh air unit with dual cooling sources proposed by the utility model has the advantages of simple structure, easy control, convenient maintenance, low manufacturing cost, and is suitable for popularization and use.

Description of drawings

Accompanying drawing 1 is the structural representation of the utility model embodiment one;

Accompanying drawing 2 is the curve diagram of the fresh air centralized treatment secondary return air system in the utility model embodiment one;

Accompanying drawing 3 is a curve diagram of the dry coil treatment system in Embodiment 1 of the present utility model;

Accompanying drawing 4 is the curve diagram of the humidity priority treatment system in Embodiment 1 of the present utility model.

Among them: 1. 1. Coarse effect filter; 2. Frequency conversion motor; 3. Centrifugal fan; 4. Evening plate; 5. Medium effect filter; 6. Sub-high efficiency filter; 7. Water-cooled coil; 8. Direct Evaporative coil.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described:

Embodiment 1: Referring to the accompanying drawing 1, a fresh air unit includes a fan section, a flow equalization section, a medium-efficiency section and a sub-high-efficiency section, and a surface cooling section, a reheating section, and an air supply section. Coarse-effect sections are sequentially arranged in the section. filter 1, frequency conversion motor 2 and centrifugal fan 3, the flow equalization, medium efficiency and sub-high efficiency sections are provided with a flow equalizer 4, medium efficiency filter 5 and sub-high efficiency filter 6 in sequence, the surface cooling, secondary A water-cooling coil 7 and a direct evaporative coil 8 are sequentially arranged in the heating and air supply section. The water-cooling coil is provided with a water inlet pipe and an outlet pipe interface, and is connected to the cold water system of the centralized cooling system. The direct evaporative coil The two ends of the coil are respectively provided with refrigerant inlet and outlet ports, which are connected with the small refrigerators of the peripherals to form a complete air-conditioning system.

In use, most of the clean operation department adopts the traditional industrial constant temperature and humidity air conditioner, that is, the primary return air is reheated. Later, due to the need for energy saving, the secondary return air system is adopted. See attached figure 2, and the "humidity first" automatic control system is implemented. . The centralized treatment of fresh air is mainly to eliminate the load of fresh air to keep the whole system stable. The centralized air supply in the operating department first eliminates the indoor humidity load, and then relies on the circulation unit to control the indoor heat load, thus realizing the priority control of humidity. If the water supply temperature of the internal coil of the circulating unit is always controlled to be higher than the indoor dew point temperature, dry coil operation can be realized, as shown in Figure 3. But for the operating room, since the room is in a sterile state, it is not necessary to deliberately maintain the operation of the dry coil. Then the air-conditioning water system can be simplified, which is the "humidity priority control" system, as shown in Figure 4. This system is to achieve the dew or air supply state of the machine required for fresh air treatment. Since the fresh air unit uses secondary cooling to dehumidify, Regardless of the temperature of the chilled water in the system, it can be conveniently guaranteed to maintain the indoor air state within the allowable range with lower energy consumption.

From the above analysis, it can be seen that the dual cold source fresh air processing unit of this embodiment does not need to change the structure of the original system, not only can effectively solve the temperature and humidity control of key departments, but also is the easiest method for energy-saving renovation of key departments in hospitals. In the energy consumption analysis of the system, the use of dual cold source fresh air units can also achieve the purpose of energy saving.

1) The heat of the condenser is fully utilized in the double cold source fresh air unit to avoid excessive consumption of reheating energy.

2) The direct expansion evaporator in the double cold source fresh air unit directly exchanges heat with the air instead of the traditional secondary heat exchange, which greatly improves the heat exchange efficiency and avoids the waste of cooling capacity.

3) When the humidity priority control system is adopted, the indoor air circulation unit only needs to cool down and heat up the air, which requires less energy. And at this time, the terminal unit can use chilled water with a higher temperature.

In addition, the use of dual cold source fresh air units avoids large-scale transformation of the original system and avoids the operation of the original system under low-efficiency conditions, saving energy to a certain extent.

Embodiment 2: A fresh air unit, including a fan section, a flow equalization section, a medium-efficiency section and a sub-high-efficiency section, and a surface cooling, reheating, and air supply section. A coarse-effect filter, a variable frequency motor, and a centrifugal fan section are sequentially arranged in the fan section. Fans, the flow equalization, medium efficiency and sub-high efficiency sections are sequentially provided with flow equalizers, medium-efficiency filters and sub-high-efficiency filters, and the surface cooling, reheating and air supply sections are sequentially provided with direct evaporative disks Tubes and water-cooled coils, the two ends of the direct evaporative coil are respectively provided with refrigerant inlets and refrigerant outlets, which are connected to a small refrigerator outside, and the two ends of the water-cooled coil are provided with cold water inlets and cold water outlets , connected to the cold water system of the central cooling system.

Claims (3)

1. A fresh air unit, comprising fan section, flow equalization, medium effect and sub-high efficiency section and surface cooling, reheating and air supply section, coarse-effect filter (1), variable frequency motor ( 2) and a centrifugal blower (3), in which the flow equalization, medium efficiency and sub-high efficiency sections are successively provided with a flow equalizer (4), a medium-efficiency filter (5) and a sub-high efficiency filter (6), characterized in that : the surface cooling, reheating and air supply sections are respectively provided with a water-cooled coil (7) and a direct evaporative coil (8), the water-cooled coil is provided with a water inlet pipe and an outlet pipe interface, and the direct evaporator The type coil is provided with refrigerant inlet and outlet ports. 2. The fresh air unit according to claim 1, characterized in that: the water-cooled coil is connected to the cold water system of the central air conditioner, and the direct evaporative coil is connected to the peripheral refrigerator to form a complete air-conditioning system . 3. The fresh air unit according to claim 1, wherein the water-cooled coil is located at the upwind end, and the direct evaporative coil is located at the downwind end.

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