Refrigeration and dehumidification system based on adsorption and desorption module

Abstract

The refrigeration and dehumidification system comprises a first heat exchanger, a second heat exchanger and an additional heat exchange unit, the first heat exchanger and the second heat exchanger are connected in series, the additional heat exchange unit is used for sharing quantitative heat load of the system and reducing indoor temperature rise, and the first heat exchanger, the second heat exchanger and the additional heat exchange unit are all arranged on the same air flowing path. A moisture adsorption and desorption unit is arranged on an air flowing path between the first heat exchanger and the second heat exchanger, the additional heat exchange unit is arranged at the downstream of the second heat exchanger, and the first heat exchanger, the second heat exchanger and the additional heat exchange unit are all communicated with the compressor through a four-way valve and a refrigerant pipeline. According to the invention, efficient operation of the industrial dehumidification equipment in a medium-low temperature environment can be ensured, and effective dehumidification can be carried out while defrosting is carried out, so that the energy consumption of the equipment is reduced, and the purposes of energy conservation and emission reduction are achieved.

Description

Technical Field

[0001] The invention relates to an air dehumidification system, in particular to a refrigeration and dehumidification system based on an adsorption and desorption module. Background Art

[0002] Under normal temperature environment, the energy-saving effect of heat pump dehumidification system is more obvious, but the dehumidification capacity of heat pump dehumidification system will decrease when dehumidifying under low temperature environment. The main reason is that the evaporator needs to be defrosted after frosting, and the system cannot dehumidify during defrosting, resulting in high energy consumption. In addition, adsorption dehumidification system can perform deep dehumidification under low temperature environment, but it requires regeneration air above 60℃ to desorb the rotor, and electric heater is usually used for heating, which makes it difficult to achieve energy-saving effect.

[0003] The adsorption and desorption unit is an important component for absorbing moisture in the dehumidifier. It can be composed of a corrugated medium made of a special composite heat-resistant material. The corrugated medium contains a desiccant (polymer material, high-efficiency active silica gel, etc.). Figure 1 As shown. This design has a compact structure and provides a huge dehumidification surface. When the humid air (processed air) enters the adsorption unit, the water molecules in the air are absorbed by the desiccant in the unit, and the moisture content of the treated air is greatly reduced. When the material in the adsorption and desorption unit absorbs enough water molecules and becomes saturated, the water molecules in the unit are taken out through high-temperature air. The humid air becomes hot air and is then discharged to the outside by the fan. The dehumidification purpose is achieved by periodically switching the processed air and the high-temperature air. The principle is as follows: Figure 2 shown.

[0004] The basic principle of condensation dehumidification is to use the cooling effect of the refrigerant to lower the temperature of the air (to the dew point temperature) so that the water vapor in the air condenses into water droplets, which are then collected to achieve the dehumidification effect. The specific process is as follows:

[0005] Cooling process: The humid air first enters the evaporator (cooler). The evaporator tube is filled with refrigerant, which absorbs the heat in the air and rapidly reduces the temperature of the air.

[0006] Moisture condensation: As the air temperature decreases, when the temperature drops below the dew point temperature, the water vapor in the air will begin to condense into water droplets. These water droplets will adhere to the surface of the cooler and gradually accumulate in the condensation pan.

[0007] Drainage process: The condensed water droplets are discharged outdoors through the drain pipe, or depending on the design of the dehumidifier, they can be collected indoors.

[0008] Heating (optional): To prevent the dehumidified air from being too cold, some dehumidifiers apply slight heating during the dehumidification process to make the treated air more comfortable.

[0009] Air supply: Finally, the dry air after cooling, dehumidification (and sometimes heating) is sent back into the room, effectively reducing the indoor humidity. Figure 3 shown.

[0010] The hybrid low-temperature frost-free dehumidification system consists of heat exchanger 1, heat exchanger 2, adsorption and desorption dehumidification module, four-way valve, expansion valve, compressor and other components. Figure 4 As shown, the expansion valve is located between heat exchanger 1 and heat exchanger 2, and the four-way valve switches the evaporator function and condenser function of heat exchanger 1 and heat exchanger 2 at regular intervals. The adsorbent loaded in the adsorption-desorption unit is a polymer adsorption material that can be regenerated at low temperature. The heat discharged during the defrosting of the condenser can be used to regenerate the adsorption-desorption dehumidification module, which increases the dehumidification capacity and improves the energy efficiency of the system. The adsorption process of the system is as follows Figure 5 As shown, heat exchanger 1 acts as an evaporator and heat exchanger 2 acts as a condenser; when high-humidity air flows into heat exchanger 1, it will be condensed and dehumidified, and then flow through the adsorption and desorption unit, the moisture in the air will be further adsorbed and removed, and then the low-temperature and low-humidity air will enter heat exchanger 2 to be heated, and finally sent into the room.

[0011] The desorption process of the hybrid low-temperature frost-free dehumidification system is as follows Figure 6 As shown, heat exchanger 2 acts as an evaporator and heat exchanger 1 acts as a condenser; when the air flows through heat exchanger 1, it will be heated. When the heated air passes through the adsorption and desorption unit, the water molecules adsorbed in the adsorption mode are desorbed into the air, thereby humidifying the air to become high relative humidity air. The high relative humidity air is then condensed and dehumidified when passing through heat exchanger 2, and finally the low-temperature and low-humidity air is delivered into the room.

[0012] During the desorption process, the heat exchanger 1 acts as a condenser, and its condensation heat will defrost the frost generated during the adsorption process. On the other hand, due to the desorption effect of the adsorbent in the adsorption-desorption unit, the relative humidity of the air flowing into the heat exchanger 2 is much higher than the relative humidity of the inlet air, thereby increasing the dehumidification capacity. Compared with the heat pump dehumidification system that does not dehumidify during the defrosting process, this system uses the desorption mode of the adsorption-desorption unit to humidify the air and then efficiently dehumidify it through the evaporator.

[0013] However, there are two major problems with the hybrid low-temperature frost-free dehumidification system: (1) In general, the evaporator size in the air-conditioning system should be much smaller than the condenser to maintain the optimal design of the system. This system has the problem that the condenser and the evaporator are the same size; (2) During the desorption process, when the heat exchanger 2 is used as an evaporator for dehumidification, the air temperature at the outlet of the heat exchanger 2 will be too low, which will interfere with the preset room temperature. Summary of the invention

[0014] Purpose of the invention: The purpose of the present invention is to provide a refrigeration and dehumidification system based on an adsorption and desorption module to solve the problem of frosting of the evaporator in the heat pump dehumidification system and the problem of reduced efficiency caused by defrosting operation in the existing dehumidification system.

[0015] Technical solution: A refrigeration and dehumidification system described in the present invention comprises a first heat exchanger and a second heat exchanger connected in series and an additional heat exchange unit for sharing the quantitative heat load of the system and reducing indoor temperature rise. The first heat exchanger, the second heat exchanger and the additional heat exchange unit are all arranged on the same air flow path. A moisture adsorption and desorption unit is provided on the air flow path between the first heat exchanger and the second heat exchanger. The additional heat exchange unit is arranged downstream of the second heat exchanger. The first heat exchanger, the second heat exchanger and the additional heat exchange unit are all connected to the compressor through a four-way valve and a refrigerant pipeline.

[0016] Preferably, the additional heat exchange unit includes two heat exchangers arranged in parallel, with a stop valve provided between the two heat exchangers, one of which is arranged indoors and downstream of the second heat exchanger, and the other is arranged outdoors, and the two heat exchangers are respectively connected to the four-way valve and the compressor through a three-way pipe.

[0017] The present invention adopts a split layout, and two additional heat exchangers are added as condensers. Dehumidification is mainly performed through the indoor air circulation device, and the balance of room heat load is mainly achieved through the outdoor unit. It can not only effectively avoid the frosting phenomenon of the evaporator in the heat pump dehumidification system, but also prevent the problem of reduced efficiency caused by defrosting operation. Through the combined design of multiple heat exchangers, the dehumidification effect is effectively increased, and the heat load generated by the condenser in the room is reduced, so it has good dehumidification and energy-saving characteristics.

[0018] Preferably, a heat dissipation component is provided on the outdoor heat exchanger.

[0019] Preferably, the first heat exchanger is connected to the second heat exchanger via an expansion valve and a refrigerant pipeline.

[0020] Preferably, the moisture absorption and desorption unit is used to absorb moisture from the airflow or release moisture into the airflow when the airflow passes through the unit.

[0021] Preferably, the moisture absorption and desorption unit is provided with a polymer adsorption material that can be regenerated at low temperature.

[0022] Preferably, at least one of the moisture adsorption / desorption unit, the first heat exchanger and the second heat exchanger is provided with a device for driving the gas to flow in one direction.

[0023] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0024] The present invention adopts split installation and utilizes the effective combination of the heat pump system and the adsorption and desorption module to solve the frosting phenomenon of the evaporator in the heat pump dehumidification system and the reduced efficiency caused by the defrosting operation in the existing dehumidification system. The present invention can ensure the efficient operation of industrial dehumidification equipment in medium and low temperature environments, and can effectively dehumidify while defrosting, thereby reducing the energy consumption of the equipment and achieving the purpose of energy saving and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a moisture adsorption and desorption unit;

[0026] Figure 2 It is a schematic diagram of the principle of the moisture adsorption and desorption unit to adsorb or desorb moisture;

[0027] Figure 3 This is the working principle diagram of the condensing dehumidification system;

[0028] Figure 4 It is a structural schematic diagram of a hybrid low-temperature frost-free dehumidification system;

[0029] Figure 5 It is a schematic diagram of the moisture adsorption process of the hybrid low-temperature frost-free dehumidification system;

[0030] Figure 6 It is a schematic diagram of the moisture desorption process of the hybrid low-temperature frost-free dehumidification system;

[0031] Figure 7 It is a structural schematic diagram of the refrigeration and dehumidification system in the present invention;

[0032] Figure 8 It is a schematic diagram of the moisture adsorption process of the present invention;

[0033] Fig. 9 Enthalpy-humidity diagram of the water adsorption process of the present invention;

[0034] Fig.10 It is a schematic diagram of the water desorption process of the present invention;

[0035] Fig.11 It is the enthalpy-humidity diagram of the water desorption process of the present invention. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0037] Example 1: A refrigeration and dehumidification system based on an adsorption and desorption module Figure 7 As shown, it is mainly composed of heat exchanger 1, heat exchanger 2, heat exchanger 3, heat exchanger 4, a moisture adsorption and desorption unit, a four-way valve, an expansion valve and a compressor.

[0038] The heat exchanger 3 and the heat exchanger 4 are connected in parallel to form an additional heat exchange unit, which is used to share the quantitative heat load of the system and reduce the indoor temperature rise. The heat exchanger 1, the heat exchanger 2 and the additional heat exchange unit are connected in series with the compressor through a four-way valve and a refrigerant pipeline. The heat exchanger 1, the heat exchanger 2 and the heat exchanger 3 are all arranged on the same air flow path. The moisture adsorption and desorption unit is arranged on the air flow path between the heat exchanger 1 and the heat exchanger 2, and the heat exchanger 3 is arranged downstream of the heat exchanger 2. A stop valve is provided on the heat exchanger 3, and the heat exchanger 3 and the heat exchanger 4 are respectively connected to the four-way valve and the compressor through a three-way pipe. The heat exchanger 4 is arranged outdoors, and the heat exchanger 1, the heat exchanger 2, the heat exchanger 3 and the moisture adsorption and desorption unit are all arranged indoors. A fan or other air driving device for driving air flow is provided on the air flow path. The fan can be arranged on one side of the heat exchanger 1 or the heat exchanger 2, or the moisture adsorption and desorption unit can be designed as a rotor to drive air flow.

[0039] The expansion valve is located between heat exchanger 1 and heat exchanger 2, and the four-way valve switches the evaporator function and condenser function of heat exchanger 1 and heat exchanger 2 at regular intervals. Heat exchanger 4 is used as a heat exhaust condenser, and heat exchanger 3 is opened and closed by the stop valve according to system requirements and used as a condenser. The adsorbent in the moisture adsorption and desorption unit is a polymer adsorption material that can be regenerated at low temperature. The moisture adsorption and desorption unit is regenerated by using the exhaust heat during condenser defrosting, which can effectively improve the energy efficiency of the system.

[0040] The regeneration process of the moisture adsorption and desorption unit is completed by alternating cycles of moisture adsorption and moisture desorption. Figure 8 The specific implementation method is as follows:

[0041] Control heat exchanger 1 as an evaporator, heat exchanger 2 and heat exchanger 4 as condensers. At this time, heat exchanger 3 is in a closed state. Heat exchanger 2, which is a condenser, can heat and raise the temperature of the air appropriately. When high-humidity air flows into heat exchanger 1, it is cooled, condensed and dehumidified, and then the air flows into the moisture adsorption and desorption unit. The moisture in the air is adsorbed and fixed by the adsorbent in the moisture adsorption and desorption unit, and the air is further dehumidified when it flows through the moisture adsorption and desorption unit. Then the low-temperature and low-humidity air enters heat exchanger 2 to be heated, and finally sent into the room. Heat exchanger 4 is outdoors and used as a condenser. The main function of heat exchanger 4 is to share the system's quantitative heat load with heat exchanger 2, and does not increase the heat load in the room, thereby reducing the temperature rise of the room.

[0042] From the psychrometric diagram ( Fig. 9) can be found that process a corresponds to cooling dehumidification (air passes through heat exchanger 1), reaches the dew point temperature, the air humidity rises to 100%, and water vapor condenses into water; process b corresponds to adsorption dehumidification (air passes through the adsorption and desorption unit), and the adsorption process changes along the isenthalpic line; process c corresponds to heating (air passes through heat exchanger 2), the air temperature rises, and the relative humidity decreases; process d corresponds to outdoor heating (air passes through heat exchanger 4), the air temperature discharged from the outside increases, but the heat load of the room is not increased.

[0043] The water desorption process is as follows Fig.10 The specific implementation method is as follows:

[0044] By switching the four-way valve, heat exchanger 1 becomes a condenser, heat exchanger 2 becomes an evaporator, and heat exchangers 3 and 4 serve as condensers; when air flows into heat exchanger 1, it will be heated, and the heated air will desorb moisture from the adsorbent when it flows through the moisture absorption and desorption unit. At this time, the water molecules adsorbed in the adsorption mode are desorbed by the hot air, which is equivalent to humidifying the hot air to become high relative humidity air entering heat exchanger 2. After heat exchanger 2 condenses and dehumidifies the high relative humidity air, the low-temperature and low-humidity air enters heat exchanger 3 to be heated and finally sent into the room. Heat exchanger 4 is located outdoors and is also used as a condenser. The main function of heat exchanger 4 is to share the system's quantitative heat load with heat exchanger 3, without increasing the heat load in the room, thereby reducing the temperature rise of the room.

[0045] During the desorption process, heat exchanger 1 becomes a condenser, and its condensation heat will defrost the frost generated during the adsorption process. On the other hand, due to the moisture desorption effect of the adsorbent in the moisture adsorption and desorption unit, the relative humidity of the air flowing into heat exchanger 2 (which acts as an evaporator at this time) is much higher than the relative humidity of the air flowing into heat exchanger 1, thereby increasing the dehumidification amount. In other words, compared with the defrosting process that does not have a dehumidification effect in the heat pump dehumidification system, this device can also achieve effective dehumidification by utilizing the desorption effect of the adsorption and desorption unit, and finally achieves high-efficiency dehumidification.

[0046] From the psychrometric diagram ( Fig.11 ) can be found that process a corresponds to heating (air passes through heat exchanger 1), the air temperature increases and the relative humidity decreases; process b corresponds to dehumidification (air passes through the moisture adsorption and desorption unit), and the desorption process changes along the isenthalpic line; process c corresponds to cooling and dehumidification (air passes through heat exchanger 2), the air temperature drops to reach the dew point temperature, the air humidity rises to 100%, and water vapor condenses into water; process d corresponds to heating (air passes through heat exchanger 3); process e corresponds to outdoor heating (air passes through heat exchanger 4), the air temperature discharged from the outside increases, but the heat load of the room is not increased.

Claims

1. A refrigeration and dehumidification system, characterized in that: It includes a first heat exchanger and a second heat exchanger connected in series, and an additional heat exchange unit for sharing the quantitative heat load of the system and reducing indoor temperature rise. The first heat exchanger, the second heat exchanger and the additional heat exchange unit are all arranged on the same air flow path. A moisture adsorption and desorption unit is provided on the air flow path between the first heat exchanger and the second heat exchanger. The additional heat exchange unit is arranged downstream of the second heat exchanger. The first heat exchanger, the second heat exchanger and the additional heat exchange unit are all connected to the compressor through a four-way valve and a refrigerant pipeline.

2. The refrigeration and dehumidification system according to claim 1, characterized in that: The additional heat exchange unit includes two heat exchangers arranged in parallel, with a stop valve provided between the two heat exchangers. One heat exchanger is arranged indoors and downstream of the second heat exchanger, and the other heat exchanger is arranged outdoors. The two heat exchangers are connected to the four-way valve and the compressor respectively through three-way pipes.

3. The refrigeration and dehumidification system according to claim 1, characterized in that: The outdoor heat exchanger is provided with a heat dissipation component.

4. The refrigeration and dehumidification system according to claim 1, characterized in that: The first heat exchanger is connected to the second heat exchanger via an expansion valve and a refrigerant pipeline.

5. The refrigeration and dehumidification system according to claim 1, characterized in that: The moisture absorption and desorption unit is used to absorb moisture from or release moisture into the airflow when the airflow passes through the unit.

6. The refrigeration and dehumidification system according to claim 1, characterized in that: The moisture absorption and desorption unit is provided with a high molecular absorption material which can be regenerated at low temperature.

7. The refrigeration and dehumidification system according to claim 1, characterized in that: At least one of the moisture adsorption / desorption unit, the first heat exchanger and the second heat exchanger is provided with a device for driving the gas to flow in one direction.

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