CN109737625B - Heat pump system, control method and heat pump drying device - Google Patents

Heat pump system, control method and heat pump drying device Download PDF

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CN109737625B
CN109737625B CN201910160034.XA CN201910160034A CN109737625B CN 109737625 B CN109737625 B CN 109737625B CN 201910160034 A CN201910160034 A CN 201910160034A CN 109737625 B CN109737625 B CN 109737625B
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control valve
branch
refrigeration cycle
drying room
heat pump
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CN109737625A (en
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郑波
吕如兵
汤康
梁祥飞
庄嵘
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
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Abstract

The invention provides a heat pump system, a control method and a heat pump drying device, wherein the heat pump system comprises: a first refrigeration cycle system; a second refrigeration cycle system; the first refrigeration cycle can be independently turned on at a temperature Tin > T1 in the drying room, at which time the second refrigeration cycle can be turned off; the second refrigeration cycle can be independently turned on at a temperature Tin < T2 in the drying room, at which time the first refrigeration cycle can be turned off; the first refrigeration cycle system and the second refrigeration cycle system can be simultaneously turned on when the temperature T2 is less than or equal to Tin less than or equal to T1 in a drying room, wherein T1 is more than T2. The invention can realize the high-efficiency operation of the whole drying process of the heat pump by combining the switching of the single-stage heat pump cycle and the overlapping heat pump cycle, the open heating and the closed dehumidification modes.

Description

Heat pump system, control method and heat pump drying device
Technical Field
The invention belongs to the technical field of heat pumps, and particularly relates to a heat pump system, a control method and a heat pump drying device.
Background
When the heat pump technology is adopted for material drying, the drying temperature is higher than 80 ℃, and the conventional air source heat pump (except the CO2 heat pump) cannot realize high-efficiency operation under large temperature rise, and at the moment, cascade circulation or multistage compression circulation is generally adopted. The cascade heat pump connects two heat pump systems through the condensing evaporator, and solves the problems of difficult system design, difficult oil balancing of the compressor and the like possibly existing in multistage compression while meeting the requirement of high heat supply temperature under the condition of large temperature rise. Patent CN103940156B presents a control method of an cascade heat pump drying system, determining the system operation mode by detecting the ambient temperature. However, the system does not consider the efficient operation of the system at different temperatures of the drying room, and also does not consider the dehumidification energy consumption of the drying and dehumidification section due to the fact that the evaporator is used for dehumidification; meanwhile, the patent proposes to use a high-temperature-level single-stage operation when the ambient temperature is high, which cannot be normally operated in the occasion of high drying temperature requirement.
Because the heat pump drying system in the prior art can not dry different drying room temperatures and can ensure the high-efficiency operation of the system, the dehumidification energy consumption can not be reduced; meanwhile, when the environment temperature is high, high-temperature-level single-stage operation is adopted, and the technical problems that the heat pump system cannot normally operate in the occasion with high drying temperature requirement are solved.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to overcome the defect that the heat pump drying system in the prior art cannot dry different drying room temperatures and can ensure the efficient operation of the system, so as to provide the heat pump system, the control method and the heat pump drying device.
The invention provides a heat pump system capable of drying materials in a drying room, comprising:
the first refrigeration cycle system comprises a first compressor, a first condenser, a first evaporator and a heat exchanger, wherein the heat exchangers are arranged at two ends of the first evaporator in parallel, and the first refrigeration cycle system is filled with a first refrigerant;
the second refrigeration cycle system comprises a second compressor, a second condenser, a second evaporator and the heat exchanger, wherein the heat exchangers are arranged at two ends of the second condenser in parallel, the first refrigeration cycle system and the second refrigeration cycle system exchange heat through the heat exchangers, and the second refrigeration cycle system is filled with a second refrigerant;
the first refrigeration cycle can be independently turned on when the temperature Tin > T1 in the drying room, at which time the second refrigeration cycle can be turned off; the second refrigeration cycle can be independently turned on when the temperature Tin in the drying room is less than T2, and the first refrigeration cycle can be turned off at the same time; the first refrigeration cycle system and the second refrigeration cycle system can be simultaneously turned on when the temperature T2 is less than or equal to Tin less than or equal to T1 in a drying room, wherein T1 is more than T2.
Preferably, the method comprises the steps of,
when the first refrigeration cycle system is independently started, the heat exchanger does not work, and the first evaporator and the first condenser work;
when the second refrigeration cycle system is independently started, the heat exchanger does not work, and the second evaporator and the second condenser work;
when the first refrigeration cycle system and the second refrigeration cycle system are simultaneously started, the heat exchanger works, the first evaporator does not work, and the second condenser does not work.
Preferably, the method comprises the steps of,
the branch where the first evaporator is located is a first branch, and a first control valve is arranged on the first branch; the branch circuit of the first refrigeration cycle system where the heat exchanger is a second branch circuit, a second control valve is arranged on the second branch circuit, and the first branch circuit is connected with the second branch circuit in parallel.
Preferably, the method comprises the steps of,
the branch where the first condenser is located is a third branch, the first refrigeration cycle system further comprises a fourth branch which is arranged in parallel with the third branch, an auxiliary condenser is arranged on the fourth branch, and a third control valve and a first throttle valve are further arranged on the fourth branch; and a second throttle valve is arranged between the third branch and the fourth branch after converging and before branching the first branch and the second branch.
Preferably, the method comprises the steps of,
the branch where the second condenser is located is a fifth branch, a fourth control valve is arranged on the fifth branch, the branch where the heat exchanger is located in the second refrigeration cycle system is a sixth branch, a fifth control valve is arranged on the sixth branch, and the fifth branch is connected with the sixth branch in parallel.
Preferably, the method comprises the steps of,
the branch where the second evaporator is located is a seventh branch, a third throttle valve and a sixth control valve are arranged on the seventh branch, the heat pump system further comprises an eighth branch, one end of the eighth branch is connected to the exhaust end of the second compressor, the other end of the eighth branch is connected between the sixth control valve and the third throttle valve, and a seventh control valve is arranged on the eighth branch.
Preferably, the method comprises the steps of,
the device further comprises a ninth branch which is arranged in parallel with the seventh branch, an auxiliary heater is further arranged on the ninth branch, and a fourth throttle valve and an eighth control valve are further arranged on the ninth branch; a ninth control valve is further arranged between the ninth branch and the seventh branch.
The invention also provides a control method of a heat pump system, which uses the heat pump system of any one of the preceding claims to control the first refrigeration cycle system to be independently turned on when the temperature Tin in a drying room is more than T1, and the second refrigeration cycle system to be turned off at the moment; controlling the second refrigeration cycle system to be independently turned on when the temperature Tin in the drying room is less than T2, and turning off the first refrigeration cycle system at the moment; and controlling the first refrigeration cycle system and the second refrigeration cycle system to be simultaneously started when the temperature T2 is less than or equal to Tin and less than or equal to T1 in the drying room.
Preferably, the method comprises the steps of,
when the first control valve, the second control valve, the third control valve, and the fourth control valve, the fifth control valve, the sixth control valve, the seventh control valve, the eighth control valve, and the ninth control valve are included:
and when the temperature Tin in the drying room is more than T1, the fourth control valve, the fifth control valve, the sixth control valve, the seventh control valve, the eighth control valve and the ninth control valve are all controlled to be closed, the third control valve is controlled to be opened, the first control valve is opened, and the second control valve is controlled to be closed.
Preferably, the method comprises the steps of,
when the first control valve, the second control valve, the third control valve, and the fourth control valve, the fifth control valve, the sixth control valve, the seventh control valve, the eighth control valve, and the ninth control valve are included:
when the temperature T2 in the drying room is less than or equal to Tin and less than or equal to T1, the second control valve is controlled to be opened, and the third control valve and the first control valve are controlled to be closed; and controlling the fifth control valve, the ninth control valve and the sixth control valve to be opened, and controlling the fourth control valve, the seventh control valve and the eighth control valve to be closed.
Preferably, the method comprises the steps of,
when the first control valve, the second control valve, the third control valve, and the fourth control valve, the fifth control valve, the sixth control valve, the seventh control valve, the eighth control valve, and the ninth control valve are included:
when the temperature Tin in the drying room is less than T2, the first control valve, the second control valve and the third control valve are controlled to be closed; and controlling the fourth control valve and the sixth control valve to be opened, and controlling the fifth control valve, the ninth control valve, the seventh control valve and the eighth control valve to be closed.
Preferably, the method comprises the steps of,
when defrosting of the second evaporator is required: when the first control valve, the second control valve, the third control valve, and the fourth control valve, the fifth control valve, the sixth control valve, the seventh control valve, the eighth control valve, and the ninth control valve are included:
when the temperature Tin in the drying room is less than or equal to T1, the first control valve, the second control valve, the third control valve, the fourth control valve, the sixth control valve and the eighth control valve are all controlled to be closed, and the seventh control valve is controlled to be opened.
Preferably, the method comprises the steps of,
when the temperature Tin in the dry room is < T2: the fourth control valve, the ninth control valve and the eighth control valve are all controlled to be opened;
when the temperature T2 in the drying room is less than or equal to Tin < T1: the fifth control valve and the eighth control valve are also controlled to be opened.
The invention also provides a heat pump drying device, which comprises the heat pump system of any one of the previous claims, and further comprises a drying room, wherein the heat pump system can heat and/or dehumidify the drying room.
Preferably, the method comprises the steps of,
the drying room is characterized by further comprising an air duct positioned in the drying room, and the first evaporator, the first condenser and the second condenser are arranged in the air duct.
Preferably, the method comprises the steps of,
and a fan is arranged in the air duct and is positioned between the first evaporator and the first condenser or between the first evaporator and the second condenser.
The heat pump system, the control method and the heat pump drying device provided by the invention have the following beneficial effects:
1. according to the invention, the first refrigeration circulation system and the second refrigeration circulation system are arranged and overlapped through the heat exchanger, so that high-temperature heating gas can be provided, different operation modes of the system are determined through different detected temperature range intervals in the drying room, when the drying room is in a low-temperature interval, the second refrigeration circulation system with a relatively low boiling point of the refrigerant is only started, the first refrigeration circulation system with a relatively high boiling point is closed, a heating function (open circulation) is provided in the drying room, a rapid heating effect is realized on the drying room, and compared with an electric heating mode, the energy efficiency is greatly improved; when the drying room is in a medium temperature zone, the first refrigeration cycle system and the second refrigeration cycle system are started simultaneously, and the cascade type is utilized to enable the first refrigeration cycle system to absorb heat from the second refrigeration cycle system, so that the air temperature is increased, and the energy efficiency is improved; when the drying room is in a high-temperature zone, a first refrigeration cycle system with a relatively high boiling point is started to provide heating and dehumidifying functions (closed cycle) for the drying room, so that the latent heat of high-temperature vapor is effectively recovered, and the energy efficiency of the system is effectively improved; the heat pump drying whole process is efficiently operated by combining the switching of the single-stage heat pump cycle and the cascade heat pump cycle, the open heating mode and the closed dehumidification mode;
2. the invention also meets the heat required by continuous heating in the defrosting process by arranging the auxiliary heater, ensures the continuous heating process, and avoids the problem of slow heating temperature rise caused by defrosting.
Drawings
FIG. 1 is a schematic view of the cycle structure of the heat pump system of the present invention;
fig. 2 is a schematic structural view of the heat pump drying apparatus of the present invention.
The reference numerals in the drawings are as follows:
101. a first compressor; 121. a first condenser; 132. a first evaporator; 131. a heat exchanger; 122. an auxiliary condenser; 201. a second compressor; 221. a second condenser; 231. a second evaporator; 232. an auxiliary heater; 301. a first branch; 302. a second branch; 303. a third branch; 304. a fourth branch; 305. a fifth branch; 306. a sixth branch; 307. a seventh branch; 308. an eighth branch; 309. a ninth branch; 105. a first control valve; 106. a second control valve; 102. a third control valve; 203. a fourth control valve; 202. a fifth control valve; 206. a sixth control valve; 204. a seventh control valve; 208. an eighth control valve; 205. a ninth control valve; 103. a first throttle valve; 104. a second throttle valve; 207. a third throttle valve; 209. a fourth throttle valve; 10. a drying room; 20. an air duct; 111. a blower.
Detailed Description
As shown in fig. 1-2, the present invention provides a heat pump system that can be used for drying materials in a drying room, comprising:
the first refrigeration cycle system comprises a first compressor 101, a first condenser 121, a first evaporator 132 and a heat exchanger 131, wherein the heat exchangers 131 are arranged at two ends of the first evaporator 132 in parallel, and the first refrigeration cycle system is filled with a first refrigerant;
the second refrigeration cycle system comprises a second compressor 201, a second condenser 221, a second evaporator 231 and the heat exchanger 131, wherein the heat exchangers 131 are arranged at two ends of the second condenser 221 in parallel, the first refrigeration cycle system exchanges heat with the second refrigeration cycle system through the heat exchanger 131, the second refrigeration cycle system is filled with a second refrigerant, and the boiling point of the first refrigerant is larger than that of the second refrigerant;
the first refrigeration cycle can be independently turned on at a temperature Tin > T1 in the drying room, at which time the second refrigeration cycle can be turned off; the second refrigeration cycle can be independently turned on at a temperature Tin < T2 in the drying room, at which time the first refrigeration cycle can be turned off; the first refrigeration cycle system and the second refrigeration cycle system can be simultaneously turned on when the temperature T2 is less than or equal to Tin less than or equal to T1 in a drying room, wherein T1 is more than T2.
According to the invention, the first refrigeration circulation system and the second refrigeration circulation system are arranged and overlapped through the heat exchanger, so that high-temperature heating gas can be provided, different operation modes of the system are determined through different detected temperature range intervals in the drying room, when the drying room is in a low-temperature interval, the second refrigeration circulation system with a relatively low boiling point of the refrigerant is only started, the first refrigeration circulation system with a relatively high boiling point is closed, a heating function (open circulation) is provided in the drying room, a rapid heating effect is realized on the drying room, and compared with an electric heating mode, the energy efficiency is greatly improved; when the drying room is in a medium temperature zone, the first refrigeration cycle system and the second refrigeration cycle system are started simultaneously, and the cascade type is utilized to enable the first refrigeration cycle system to absorb heat from the second refrigeration cycle system, so that the air temperature is increased, and the energy efficiency is improved; when the drying room is in a high-temperature zone, a first refrigeration cycle system with a relatively high boiling point is started to provide heating and dehumidifying functions (closed cycle) for the drying room, so that the latent heat of high-temperature vapor is effectively recovered, and the energy efficiency of the system is effectively improved; the heat pump drying whole process is efficiently operated by combining the switching of the single-stage heat pump cycle and the cascade heat pump cycle, and the open heating and closed dehumidification modes.
When the temperature of the drying room is lower, the low-temperature stage (subsystem 2) in the cascade system operates, and under the condition of low pressure ratio, the efficiency of single-stage operation is higher than that of the cascade system;
the temperature of the drying room is increased, the pressure ratio is increased, and the cascade operation efficiency is higher than that of the single-stage operation, so that the high-temperature stage and the low-temperature stage (subsystem 1 and subsystem 2) are operated;
when the temperature of the drying room reaches a certain preset value and enters a dehumidification operation mode, the whole drying system is operated in a closed mode, the evaporator recovers latent heat of condensed water, and only the high-temperature stage (subsystem 1) is operated.
Preferably, the method comprises the steps of,
when the first refrigeration cycle is independently turned on, the heat exchanger 131 is not operated, and the first evaporator 132 and the first condenser 121 are operated;
when the second refrigeration cycle is independently turned on, the heat exchanger 131 is not operated, and the second evaporator 231 and the second condenser 221 are operated;
when the first and second refrigeration cycle systems are simultaneously turned on, the heat exchanger 131 is operated, the first evaporator 132 is not operated, and the second condenser 221 is not operated.
The first refrigeration cycle system is independently started, the second refrigeration cycle system is independently started and the first refrigeration cycle system and the second refrigeration cycle system are simultaneously started in respective optimal control modes, the first refrigeration cycle system is independently started to correspond to a high-temperature working condition, at the moment, a heat exchanger is not required to be started, heat absorption from the outside of a drying room is not required, only the first evaporator and the first condenser are required to work, at the moment, the first evaporator and the first condenser are both positioned in the drying room, the heating and dehumidifying effects can be completed in the drying room, the evaporation latent heat of vapor is effectively recovered, and the energy efficiency is improved; the second refrigeration cycle system is independently started to correspond to a low-temperature working condition, at the moment, a heat exchanger does not need to be started, heat absorption is needed to be carried out from the outside of the drying room, the second evaporator and the second condenser are started to work, heat absorption is needed to be carried out from the outside of the drying room, the inside of the drying room is heated, the effect of rapid heating is achieved, and the energy efficiency is improved compared with modes such as electric heating; the first refrigeration cycle system and the second refrigeration cycle system are both started to correspond to medium-temperature working conditions, and at the moment, the heat exchanger is started, heat is required to be absorbed from the outside of the drying room, so that the heating effect is improved, the effect of preparing high-temperature air is realized, and the energy efficiency is improved.
Preferably, the method comprises the steps of,
the branch where the first evaporator 132 is located is a first branch 301, and a first control valve 105 is disposed on the first branch 301; in the first refrigeration cycle system, the branch where the heat exchanger 131 is located is a second branch 302, and the second branch 302 is provided with a second control valve 106, and the first branch 301 is connected in parallel with the second branch 302. This is a preferred embodiment of the heat pump system according to the invention, in which the first evaporator is controlled by a first control valve and the second branch is controlled by a second control valve.
Preferably, the method comprises the steps of,
the branch where the first condenser 121 is located is a third branch 303, and the first refrigeration cycle system further includes a fourth branch 304 that is parallel to the third branch 303, where the fourth branch 304 is provided with an auxiliary condenser 122, and the fourth branch 304 is further provided with a third control valve 102 and a first throttle valve 103; a second throttle valve 104 is disposed between the third branch 303 and the fourth branch 304 after they meet and before the first branch 301 and the second branch 302 branch. This is a preferred embodiment of the heat pump system according to the invention, in which the auxiliary condenser is controlled by a third control valve and the flow rate is controlled by a first throttle valve, and the second throttle valve controls the throttle pressure reduction of the first refrigerant in the entire circulation system.
Preferably, the method comprises the steps of,
the branch where the second condenser 221 is located is a fifth branch 305, a fourth control valve 203 is disposed on the fifth branch 305, the branch where the heat exchanger 131 is located in the second refrigeration cycle system is a sixth branch 306, and a fifth control valve 202 is disposed on the sixth branch 306, and the fifth branch 305 is connected in parallel with the sixth branch 306. This is a preferred embodiment of the heat pump system according to the invention, in which the second condenser is controlled by a fourth control valve and the sixth branch is controlled by a fifth control valve.
Preferably, the method comprises the steps of,
the branch where the second evaporator 231 is located is a seventh branch 307, a third throttle valve 207 and a sixth control valve 206 are disposed on the seventh branch 307, and the heat pump system further includes an eighth branch 308, one end of the eighth branch 308 is connected to the exhaust end of the second compressor 201, the other end is connected between the sixth control valve 206 and the third throttle valve 207, and a seventh control valve 204 is disposed on the eighth branch. This is a preferred embodiment of the heat pump system according to the invention, i.e. the second evaporator is controlled by a sixth control valve and the throttle flow is controlled by a third throttle valve, the eighth branch being arranged to bypass the heat of the compressor to the second evaporator 231 for defrosting.
Preferably, the method comprises the steps of,
a ninth branch 309 connected in parallel with the seventh branch 307 is further included, an auxiliary heater 232 is further disposed on the ninth branch 309, and a fourth throttle valve 209 and an eighth control valve 208 are further disposed on the ninth branch 309; a ninth control valve 205 is also arranged between the ninth branch 309 and the seventh branch 307. In the preferred embodiment of the heat pump system of the present invention, the auxiliary heater is provided to heat the refrigerant, thereby effectively defrosting the second evaporator, the eighth control valve is used to control the flow rate of the refrigerant, the third throttle valve is used to control the flow rate of the refrigerant, and the ninth control valve is used to further effectively control the flow rate of the refrigerant.
The invention also provides a control method of a heat pump system, which uses the heat pump system of any one of the preceding claims to control the first refrigeration cycle system to be independently turned on when the temperature Tin in a drying room is more than T1, and the second refrigeration cycle system to be turned off at the moment; controlling the second refrigeration cycle system to be independently turned on when the temperature Tin in the drying room is less than T2, and turning off the first refrigeration cycle system at the moment; and controlling the first refrigeration cycle system and the second refrigeration cycle system to be simultaneously started when the temperature T2 is less than or equal to Tin and less than or equal to T1 in the drying room.
According to the invention, the first refrigeration circulation system and the second refrigeration circulation system are arranged and overlapped through the heat exchanger, so that high-temperature heating gas can be provided, different operation modes of the system are determined through different detected temperature range intervals in the drying room, when the drying room is in a low-temperature interval, the second refrigeration circulation system with a relatively low boiling point of the refrigerant is only started, the first refrigeration circulation system with a relatively high boiling point is closed, a heating function (open circulation) is provided in the drying room, a rapid heating effect is realized on the drying room, and compared with an electric heating mode, the energy efficiency is greatly improved; when the drying room is in a medium temperature zone, the first refrigeration cycle system and the second refrigeration cycle system are started simultaneously, and the cascade type is utilized to enable the first refrigeration cycle system to absorb heat from the second refrigeration cycle system, so that the air temperature is increased, and the energy efficiency is improved; when the drying room is in a high-temperature zone, a first refrigeration cycle system with a relatively high boiling point is started to provide heating and dehumidifying functions (closed cycle) for the drying room, so that the latent heat of high-temperature vapor is effectively recovered, and the energy efficiency of the system is effectively improved; the heat pump drying whole process is efficiently operated by combining the switching of the single-stage heat pump cycle and the cascade heat pump cycle, and the open heating and closed dehumidification modes.
The invention provides a control method of a heat pump drying system, the heat pump system is formed by overlapping a subsystem 1 (a first refrigeration cycle system) and a subsystem 2 (a second refrigeration cycle system), the subsystem 1 is provided with a first compressor 101, a first condenser 121, an auxiliary condenser 122, a throttling device, a heat exchanger 131, a first evaporator 132 and a stop valve, the subsystem 2 is provided with a second compressor 201, a second condenser 221, a heat exchanger 131, a throttling device, a second evaporator 231, an auxiliary heater 232 and a stop valve, and the evaporator 1 of the subsystem 1 and the heat exchanger 131 of the subsystem 2 form the overlapping 1. The control method comprises a control method of drying room temperature Tin > T1, a control method of drying room temperature Tin < T2 and a control method of T2-drying room temperature Tin-T1, wherein T1 and T2 are related to outdoor environment temperature Tout, and T1> T2. Different control methods are determined according to different drying room temperatures.
When the temperature of the drying room is lower, the low-temperature stage (subsystem 2) in the cascade system operates, and under the condition of low pressure ratio, the efficiency of single-stage operation is higher than that of the cascade system;
the temperature of the drying room is increased, the pressure ratio is increased, and the cascade operation efficiency is higher than that of the single-stage operation, so that the high-temperature stage and the low-temperature stage (subsystem 1 and subsystem 2) are operated;
when the temperature of the drying room reaches a certain preset value and enters a dehumidification operation mode, the whole drying system is operated in a closed mode, the evaporator recovers latent heat of condensed water, and only the high-temperature stage (subsystem 1) is operated.
Preferably, the method comprises the steps of,
when the first control valve 105, the second control valve 106, the third control valve 102, and the fourth control valve 203, the fifth control valve 202, the sixth control valve 206, the seventh control valve 204, the eighth control valve 208, and the ninth control valve 205 are included:
and when the temperature Tin > T1 in the drying room, the fourth control valve 203, the fifth control valve 202, the sixth control valve 206, the seventh control valve 204, the eighth control valve 208 and the ninth control valve 205 are all controlled to be closed, and the third control valve 102 is controlled to be opened, the first control valve 105 is controlled to be opened, and the second control valve 106 is controlled to be closed. The refrigerant flow direction in the subsystem 1 is sequentially a first compressor 101, a first condenser 121 and an auxiliary condenser 122, a second throttle valve 104, a first evaporator 132 and the first compressor 101, at this time, the first condenser 121 and the auxiliary condenser 122 are connected in parallel, and the refrigerant flow rate flowing through the auxiliary condenser 122 is regulated by the first throttle valve 103.
The method is a specific control means and a specific control mode when the temperature Tin in the drying room is more than T1, namely, the second refrigeration cycle system (subsystem 2) is closed, only the first refrigeration cycle system (subsystem 1) is opened, a branch where the heat exchanger 131 is positioned and a branch where the auxiliary condenser is positioned are opened, the functions of drying, heating and dehumidification can be completed in the drying room through the first condenser and the first evaporator, and the temperature in the drying room can be regulated and controlled through the auxiliary condenser (arranged outside the drying room) and energy supplement can be formed.
Preferably, the method comprises the steps of,
when the first control valve 105, the second control valve 106, the third control valve 102, and the fourth control valve 203, the fifth control valve 202, the sixth control valve 206, the seventh control valve 204, the eighth control valve 208, and the ninth control valve 205 are included:
and when the temperature T2 is less than or equal to Tin is less than or equal to T1 in the drying room, controlling the second control valve 106 to be opened and controlling the third control valve 102 and the first control valve 105 to be closed; the fifth control valve 202, the ninth control valve 205, and the sixth control valve 206 are controlled to be opened, and the fourth control valve 203, the seventh control valve 204, and the eighth control valve 208 are controlled to be closed. The refrigerant flow direction in the subsystem 2 is the second compressor 201, the condensing channel side of the heat exchanger 131, the third throttle valve 207, the second evaporator 231 and the second compressor 201 in this order, and the refrigerant flow direction in the subsystem 1 is the first compressor 101, the first condenser 121, the second throttle valve 104, the heat exchanger 131 and the first compressor 101 in this order.
The method is a specific control means and a specific control mode when the temperature T2 is less than or equal to Tin and less than or equal to T1 in the drying room, namely, a first refrigeration cycle system (subsystem 1) and a second refrigeration cycle system (subsystem 2) are simultaneously started, a branch where the heat exchanger 131 is opened, a branch where the auxiliary condenser is closed, a branch where the second condenser 221 is closed are opened, a drying and heating function (open cycle, because only the first condenser is positioned in the drying room) can be completed in the drying room through the first condenser, a heating effect with higher temperature can be realized through the heat exchanger, and the energy efficiency is improved.
Preferably, the method comprises the steps of,
when the first control valve 105, the second control valve 106, the third control valve 102, and the fourth control valve 203, the fifth control valve 202, the sixth control valve 206, the seventh control valve 204, the eighth control valve 208, and the ninth control valve 205 are included:
and when the temperature Tin in the drying room is less than T2, the first control valve 105, the second control valve 106 and the third control valve 102 are controlled to be closed; the fourth control valve 203 and the sixth control valve 206 are controlled to be opened, and the fifth control valve 202, the ninth control valve 205, the seventh control valve 204, and the eighth control valve 208 are controlled to be closed. The refrigerant flow direction in the subsystem 2 is the second compressor 201, the second condenser 221, the third throttle 207, the second evaporator 231, and the second compressor 201 in this order.
This is a specific control means and control manner when the temperature Tin in the drying room is less than T2 in the present invention, that is, the first refrigeration cycle system (subsystem 1) is turned off, only the second refrigeration cycle system (subsystem 2) is turned on, and the branch where the heat exchanger 131 is located and the branch where the second evaporator and the second condenser 221 are located are turned on, through which the drying and heating functions (open cycle, because the second evaporator is located outside the drying room) can be completed in the drying room, and rapid heating is performed.
Preferably, the method comprises the steps of,
when it is desired to defrost the second evaporator 231: when the first control valve 105, the second control valve 106, the third control valve 102, and the fourth control valve 203, the fifth control valve 202, the sixth control valve 206, the seventh control valve 204, the eighth control valve 208, and the ninth control valve 205 are included:
when the temperature Tin in the drying room is equal to or less than T1, the first control valve 105, the second control valve 106, the third control valve 102, the fourth control valve 203, the sixth control valve 206 and the eighth control valve 208 are all controlled to be closed, and the seventh control valve 204 is controlled to be opened.
This is a preferred control of the defrost process of the invention, whereby the opening of the eighth branch enables the heat of the compressor to be transferred into the second evaporator for defrosting the second evaporator.
The defrost branch refrigerant flows to the second compressor 201, the seventh control valve 204, the third throttle valve 207, the second evaporator 231, and the second compressor 201 in this order. At this time, when the drying room temperature Tin < T2, the flow direction of the refrigerant of the heating branch of the subsystem 2 is the second compressor 201, the fourth control valve 203, the second condenser 221, the ninth control valve 205, the eighth control valve 208, the fourth throttle valve 209, the auxiliary heater 232 and the second compressor 201 in this order, and the fifth control valve 202 is closed; when T2 is less than or equal to the temperature Tin of the drying room and less than or equal to T1, the flow direction of the refrigerant of the heating branch of the subsystem 2 is sequentially a second compressor 201, a fifth control valve 202, a heat exchanger 131, an eighth control valve 208, an auxiliary heater 232 and the second compressor 201, and a fourth control valve 203 is closed.
Preferably, the method comprises the steps of,
when the temperature Tin in the dry room is < T2: also controlling the fourth control valve 203, the ninth control valve 205 and the eighth control valve 208 to be opened;
when the temperature T2 in the drying room is less than or equal to Tin < T1: the fifth control valve 202 and the eighth control valve 208 are also controlled to be opened.
The invention is a control mode for further defrosting, namely, the second condenser and the auxiliary heater can be used for heating the refrigerant to defrost the second evaporator, or the heat exchanger and the auxiliary heater can be used for heating the refrigerant to defrost the second evaporator. The auxiliary heater is arranged to meet the requirement of continuously heating the defrosting process, so that the heating process is ensured to be continuous, and the problem of slow heating temperature rising process caused by defrosting is avoided.
The invention also provides a heat pump drying device, which comprises the heat pump system as claimed in any preceding claim, and further comprises a drying room 10, wherein the heat pump system can heat and/or dehumidify the drying room 10.
According to the invention, the first refrigeration circulation system and the second refrigeration circulation system are arranged and overlapped through the heat exchanger, so that high-temperature heating gas can be provided, different operation modes of the system are determined through different detected temperature range intervals in the drying room, when the drying room is in a low-temperature interval, the second refrigeration circulation system with a relatively low boiling point of the refrigerant is only started, the first refrigeration circulation system with a relatively high boiling point is closed, a heating function (open circulation) is provided in the drying room, a rapid heating effect is realized on the drying room, and compared with an electric heating mode, the energy efficiency is greatly improved; when the drying room is in a medium temperature zone, the first refrigeration cycle system and the second refrigeration cycle system are started simultaneously, and the cascade type is utilized to enable the first refrigeration cycle system to absorb heat from the second refrigeration cycle system, so that the air temperature is increased, and the energy efficiency is improved; when the drying room is in a high-temperature zone, a first refrigeration cycle system with a relatively high boiling point is started to provide heating and dehumidifying functions (closed cycle) for the drying room, so that the latent heat of high-temperature vapor is effectively recovered, and the energy efficiency of the system is effectively improved; the heat pump drying whole process is efficiently operated by combining the switching of the single-stage heat pump cycle and the cascade heat pump cycle, and the open heating and closed dehumidification modes.
Preferably, the method comprises the steps of,
and an air duct 20 positioned in the drying room 10, wherein the first evaporator 132, the first condenser 121 and the second condenser 221 are arranged in the air duct 20. The heat pump drying device is a preferable structural form, and the air flow can be heated or dehumidified through the plurality of heat exchangers in the air channel by arranging the air channel, and the air flow after heating and/or dehumidification is conveyed into the drying material to complete heating and/or dehumidification.
Preferably, the method comprises the steps of,
a fan 111 is further disposed in the air duct 20, and the fan 111 is located between the first evaporator 132 and the first condenser 121 or between the first evaporator 132 and the second condenser 221. This is a further preferred form of construction of the invention whereby the heat exchange effect can be enhanced by the fan, enhancing the heating and/or dehumidifying action.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention. The foregoing is merely a preferred embodiment of the present invention, and it should be noted that it will be apparent to those skilled in the art that modifications and variations can be made without departing from the technical principles of the present invention, and these modifications and variations should also be regarded as the scope of the invention.

Claims (10)

1. The utility model provides a heat pump system can be used for drying the material in the drying room, its characterized in that: comprising the following steps:
the first refrigeration cycle system comprises a first compressor (101), a first condenser (121), a first evaporator (132) and heat exchangers (131), wherein the heat exchangers (131) are arranged at two ends of the first evaporator (132) in parallel, and the first refrigeration cycle system is filled with a first refrigerant;
the second refrigeration cycle system comprises a second compressor (201), a second condenser (221), a second evaporator (231) and a heat exchanger (131), wherein the heat exchanger (131) is arranged at two ends of the second condenser (221) in parallel, the first refrigeration cycle system and the second refrigeration cycle system exchange heat through the heat exchanger (131), and the second refrigeration cycle system is filled with a second refrigerant;
the first refrigeration cycle can be independently turned on at a temperature Tin > T1 in the drying room, at which time the second refrigeration cycle can be turned off; the second refrigeration cycle can be independently turned on at a temperature Tin < T2 in the drying room, at which time the first refrigeration cycle can be turned off; the first refrigeration cycle system and the second refrigeration cycle system can be simultaneously started when the temperature T2 is less than or equal to Tin and less than or equal to T1 in a drying room, wherein T1 is more than T2;
the branch where the first evaporator (132) is located is a first branch (301), and a first control valve (105) is arranged on the first branch (301); in the first refrigeration cycle system, a branch where the heat exchanger (131) is located is a second branch (302), a second control valve (106) is arranged on the second branch (302), and the first branch (301) is connected with the second branch (302) in parallel;
the branch where the first condenser (121) is located is a third branch (303), the first refrigeration cycle system further comprises a fourth branch (304) which is arranged in parallel with the third branch (303), an auxiliary condenser (122) is arranged on the fourth branch (304), and a third control valve (102) and a first throttle valve (103) are also arranged on the fourth branch (304); a second throttle valve (104) is arranged between the third branch (303) and the fourth branch (304) after converging and before branching the first branch (301) and the second branch (302);
the branch where the second condenser (221) is located is a fifth branch (305), a fourth control valve (203) is arranged on the fifth branch (305), the branch where the heat exchanger (131) is located in the second refrigeration cycle system is a sixth branch (306), a fifth control valve (202) is arranged on the sixth branch (306), and the fifth branch (305) is connected with the sixth branch (306) in parallel;
the branch where the second evaporator (231) is located is a seventh branch (307), a third throttle valve (207) and a sixth control valve (206) are arranged on the seventh branch (307), the heat pump system further comprises an eighth branch (308), one end of the eighth branch (308) is connected to the exhaust end of the second compressor (201), the other end of the eighth branch is connected between the sixth control valve (206) and the third throttle valve (207), and a seventh control valve (204) is arranged on the eighth branch;
the device further comprises a ninth branch (309) which is arranged in parallel with the seventh branch (307), an auxiliary heater (232) is further arranged on the ninth branch (309), and a fourth throttle valve (209) and an eighth control valve (208) are further arranged on the ninth branch (309); a ninth control valve (205) is further arranged between the ninth branch (309) and the seventh branch (307);
when the temperature Tin in the drying room is less than T2, the first control valve (105), the second control valve (106) and the third control valve (102) are controlled to be closed; the fourth control valve (203) and the sixth control valve (206) are controlled to be opened, and the fifth control valve (202), the ninth control valve (205), the seventh control valve (204) and the eighth control valve (208) are controlled to be closed.
2. The heat pump system of claim 1, wherein:
when the first refrigeration cycle system is independently started, the heat exchanger (131) does not work, and the first evaporator (132) and the first condenser (121) work;
when the second refrigeration cycle is independently turned on, the heat exchanger (131) is not operated, and the second evaporator (231) and the second condenser (221) are operated;
when the first refrigeration cycle system and the second refrigeration cycle system are simultaneously turned on, the heat exchanger (131) is operated, the first evaporator (132) is not operated, and the second condenser (221) is not operated.
3. A control method of a heat pump system, characterized by:
use of the heat pump system of any one of claims 1-2 to control the first refrigeration cycle to be individually turned on when the temperature Tin > T1 in the drying room, while the second refrigeration cycle is turned off; controlling the second refrigeration cycle system to be independently turned on when the temperature Tin in the drying room is less than T2, and turning off the first refrigeration cycle system at the moment; when the temperature T2 is less than or equal to Tin and less than or equal to T1 in a drying room, controlling the first refrigeration cycle system and the second refrigeration cycle system to be simultaneously started;
when the temperature Tin in the drying room is less than T2, the first control valve (105), the second control valve (106) and the third control valve (102) are controlled to be closed; the fourth control valve (203) and the sixth control valve (206) are controlled to be opened, and the fifth control valve (202), the ninth control valve (205), the seventh control valve (204) and the eighth control valve (208) are controlled to be closed.
4. A control method according to claim 3, characterized in that:
when a first control valve (105), a second control valve (106), a third control valve (102), and a fourth control valve (203), a fifth control valve (202), a sixth control valve (206), a seventh control valve (204), an eighth control valve (208), and a ninth control valve (205) are included:
and when the temperature Tin > T1 in the drying room, the fourth control valve (203), the fifth control valve (202), the sixth control valve (206), the seventh control valve (204), the eighth control valve (208) and the ninth control valve (205) are all controlled to be closed, and the third control valve (102) is controlled to be opened, the first control valve (105) is controlled to be opened, and the second control valve (106) is controlled to be closed.
5. A control method according to claim 3, characterized in that:
when a first control valve (105), a second control valve (106), a third control valve (102), and a fourth control valve (203), a fifth control valve (202), a sixth control valve (206), a seventh control valve (204), an eighth control valve (208), and a ninth control valve (205) are included:
and when the temperature T2 is less than or equal to Tin and less than or equal to T1 in the drying room, controlling the second control valve (106) to be opened and controlling the third control valve (102) and the first control valve (105) to be closed; the fifth control valve (202), the ninth control valve (205) and the sixth control valve (206) are controlled to be opened, and the fourth control valve (203), the seventh control valve (204) and the eighth control valve (208) are controlled to be closed.
6. A control method according to claim 3, characterized in that:
when defrosting of the second evaporator (231) is required: when a first control valve (105), a second control valve (106), a third control valve (102), and a fourth control valve (203), a fifth control valve (202), a sixth control valve (206), a seventh control valve (204), an eighth control valve (208), and a ninth control valve (205) are included:
when the temperature Tin in the drying room is less than or equal to T1, the first control valve (105), the second control valve (106), the third control valve (102), the fourth control valve (203), the sixth control valve (206) and the eighth control valve (208) are controlled to be closed, and the seventh control valve (204) is controlled to be opened.
7. The control method according to claim 6, characterized in that:
when the temperature Tin in the dry room is < T2: -controlling the fourth control valve (203), the ninth control valve (205) and the eighth control valve (208) to be open;
when the temperature T2 in the drying room is less than or equal to Tin < T1: the fifth control valve (202) and the eighth control valve (208) are also controlled to be opened.
8. A heat pump drying device, characterized in that: a heat pump system according to any of claims 1-2, further comprising a drying room (10), said heat pump system being capable of heating and/or dehumidifying the drying room (10).
9. The heat pump drying apparatus according to claim 8, wherein:
the drying room also comprises an air duct (20) positioned in the drying room (10), and the first evaporator (132), the first condenser (121) and the second condenser (221) are arranged in the air duct (20).
10. The heat pump drying apparatus according to claim 9, wherein:
a fan (111) is further arranged in the air duct (20), and the fan (111) is located between the first evaporator (132) and the first condenser (121) or between the first evaporator (132) and the second condenser (221).
CN201910160034.XA 2019-03-04 2019-03-04 Heat pump system, control method and heat pump drying device Active CN109737625B (en)

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