JPH0650204B2 - Absorption heat pump controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention uses a salt solution as an absorption liquid, and makes the pressure and temperature in the generator and the condenser more than the pressure and temperature in the evaporator and the absorber. Control device for absorption heat pump (hereinafter referred to as "absorption heat pump of this type") that is operated at a low temperature and takes out a heated fluid having a temperature higher than that of waste steam and other heat source fluid supplied to the generator and the evaporator from the absorber Regarding

(B) Prior art In the absorption heat pump, in order to increase the absorption liquid (lithium bromide aqueous solution) circulating in the machine to a predetermined concentration,
The refrigerant liquid reservoir is provided in the evaporator. But,
In this type of absorption heat pump, if the heat input to the generator becomes excessive due to the operating condition of the waste heat source, or if the temperature of the cooling water flowing into the condenser becomes too low due to weather fluctuations, it will The amount of refrigerant liquid stored increases more than necessary and the concentration of the absorbing liquid circulating in the machine becomes too high,
There are problems such as the absorption liquid crystallizing, clogging of the absorption liquid circulation path, and malfunction of the absorption liquid pump. There is also a problem that the absorption liquid inside the machine is crystallized after the operation of this type of absorption heat pump is stopped. Therefore, in the absorption heat pump of this type, as described in, for example, Japanese Patent Laid-Open No. 58-31262, the refrigerant liquid in the refrigerant liquid reservoirs of the evaporator and the condenser is discharged before the operation of the absorption heat pump is stopped. Means for diluting the absorbing liquid by blowing into the absorber and the generator have been conventionally used.

However, such a conventional means, although it is possible to prevent the crystallization of the absorption liquid after the operation is stopped, since the refrigerant liquid hardly remains in the refrigerant liquid reservoir of the evaporator and the condenser, when the operation is restarted, It requires a long time for the refrigerant liquid to be sprayed in the evaporator and the evaporation of the refrigerant to start, and for the absorbing liquid circulating inside the machine to take a long time to reach a predetermined concentration. ing.

(C) The object of the invention The present invention, in this type of absorption heat pump device, it is possible to prevent the crystallization of the absorption liquid after the operation is stopped and to speed up the start-up at the time of restarting the operation, and the concentration of the absorption liquid during the operation. It is an object of the present invention to provide an apparatus capable of preventing crystallization of an absorbing liquid during operation by controlling it to a predetermined position or less.

(D) Configuration of the invention The present invention, in this type of absorption heat pump device, up to this set storage amount by setting the storage amount of the refrigerant liquid in the evaporator before the absorption liquid in the generator reaches the crystal region When the refrigerant liquid in the evaporator increases during operation, and at a predetermined time before stopping the pump for absorbing liquid at the time of operation stop, the refrigerant liquid in the evaporator is discharged by the pump and the evaporator, the condenser. The pressure difference between the two causes it to be sent to the condenser, and the condenser then overflows into the generator.

According to the present invention, the refrigerant liquid in the evaporator is blown into the absorbing liquid in the generator in a short time while passing through the refrigerant liquid reservoir of the condenser by the discharge force and the pressure difference of the pump, so that the It is possible to prevent the absorption liquid from crystallizing after the operation is stopped. Moreover, according to the present invention, since a large amount of the refrigerant liquid is stored in the refrigerant liquid reservoir of the condenser, it is possible to speed up the start-up of the operation.

(E) Embodiment FIG. 1 is a schematic configuration explanatory view showing an embodiment of a control device for an absorption heat pump of this type according to the present invention, wherein (1) shows a generator (2) and a condenser (3). Consists of a lower generation condensation stage, (4) an upper vaporization absorption stage consisting of an evaporator (5) and an absorber (6), (7) a solution heat exchanger, and (8) a pump for refrigerant liquid. , (9) is a pump for recirculating the refrigerant liquid, and (10) is a pump for the absorbing liquid.
1), (12), refrigerant liquid feed pipes (13), (14), refrigerant liquid reflux pipes (15), (16), concentrated absorption liquid feed pipes (17), (18), (1
9), connected by pipes (20), (21) through which the rare absorbent flows down to form a circulation path for the refrigerant (water) and the absorbent (lithium bromide aqueous solution) similar to the conventional absorption heat pump of this type. ing. Incidentally, (22) is a heat exchange coil built in the solution heat exchanger (7).

(23) is the heater of the generator (2), (24) is the cooler of the condenser (3),
(25) is the heat supply device of the evaporator (5), (26) is the heated device of the absorber (6), and (27) and (28) are the hot waste water and waste water connected to the heater (23). Pipes for flowing heat source fluid such as steam, (29), (30) are coolers (24)
A pipe for flowing a cooling fluid such as cooling water or cooling air connected to the pipe, (31) and (32) are pipes for flowing a heat source fluid such as waste hot water and waste steam connected to the heat supply device (25), (33) , (34) are pipes connected to the device to be heated (26) for flowing a fluid to be heated such as hot water or steam.

(35) and (36) are sprayers of rare absorbent and concentrated absorbent, respectively (3
7) is a refrigerant liquid sprayer, (38), (39) are generators (2),
Solution reservoir of absorber (6), condensers (40) and (41) respectively
(3), the refrigerant reservoir of the evaporator (5), (42), (43) are eliminators, (V ₀ ) is a control valve provided in the pipe (14), (V
₁ ) is a check valve provided in the pipe (14), (D ₁ ) and (D ₂ ) are pipes (1
It is a damper for 9) and (21). Also, (S) is the solution reservoir
Liquid level switches provided in (38), (C ₁ ) and (C ₂ ) are liquid level controllers provided in the refrigerant liquid reservoirs (40) and (41), respectively.

(44) is a pipe (16) on the discharge side of the pump (9) for recirculating the refrigerant liquid
And a refrigerant liquid reservoir (40) uppermost part of the condenser (3), which is provided with an on-off valve (V) which is opened and closed by a signal of the liquid level controller (C ₂ ). Also, the pump (9) is a liquid level controller.
The start and stop control is performed by (C ₂ ), and the liquid level of the refrigerant sump (41) is maintained between the upper and lower limit levels. Similarly, the pumps (8) and (10) are controlled to start and stop by the liquid level controller (C ₁ ) and the liquid level switch (S), respectively, so that the liquid level can be maintained between the upper and lower limit levels. There is. The opening of the control valve (V ₀ ) is controlled by the liquid level controller (C ₁ ), and the opening / closing valve (V) is opened / closed by a switch (not shown) when the operation is stopped. .

Reference numeral (45) is a refrigerant liquid overflow pipe that connects the vicinity of the uppermost portion of the refrigerant liquid reservoir (40) of the condenser (3) and the upper portion of the solution reservoir (38).

By operating this type of absorption heat pump configured as described above, a cycle as shown in FIG. 2 is formed, and the cycle is higher than that of the heat source fluid supplied to the generator (2) and the evaporator (5). The fluid to be heated can be taken out from the absorber (6). Fig. 2 shows an example of a Duhring diagram when operating this type of absorption heat pump. In the figure, the G ₁ → G ₂ → A ₁ → A ₂ → G ₁ cycle is the absorption It is the rated cycle of the liquid, the W line is the temperature of the refrigerant (water) -vapor pressure line, C
Is a crystal line of the absorbing liquid (lithium bromide aqueous solution).

Next, an example of the operation of the device of the present invention will be described. During operation of the absorption heat pump, if the operating condition of equipment such as a factory or chemical plant that is a waste heat source (not shown) changes and the flow rate of the heat source fluid increases or its temperature rises, the generator
As the amount of refrigerant generated in (2) increases, the amount of refrigerant condensed in the condenser (3) increases accordingly. Alternatively, for example, when the outside air temperature decreases and the temperature of the cooling fluid flowing into the condenser (3) decreases, the condensation amount of the refrigerant in the condenser (3) increases and the generator (2) increases accordingly. The amount of refrigerant generated also increases. Then, when the load on the heated fluid side does not change, the liquid level in the refrigerant reservoir (41) of the evaporator (5) begins to rise, and the absorption liquid cycle moves to the right of the rated cycle in FIG. Begin to. In addition, in FIG. 2, it is represented by a dotted line.
G ₁ ′ → G ₂ ′ → A ₁ ′ → A ₂ ′ → G ₁ ′ cycle and G ₁ ″ →
The G ₂ ″ → A ₁ ″ → A ₂ ″ → G ₁ ″ cycle shows an example of the cycle of the absorbing liquid that has moved to the right due to the rise of the liquid level in the refrigerant liquid reservoir (41). As is clear from the position of G ₂ ′ or G ₂ ″ in this figure, in this type of absorption heat pump, if the liquid level in the refrigerant liquid reservoir (41) is left to rise, the generator ( Reservoir concentrated in 2) (38), tube
(17), it can be seen that the concentrated absorbing liquid in the tube (18) and the like first reaches the crystal region.

In the device of the present invention, when the liquid level in the refrigerant liquid reservoir (41) rises to a set level (the absorbing liquid in the generator (2) approaches the crystal region), the signal of the liquid level controller (C ₂ ) Open / close valve
(V) is opened, the refrigerant liquid in the refrigerant liquid reservoir (41) is evaporated (5),
It is sent to the refrigerant reservoir (40) of the condenser (3) by the pressure difference and the pressure drop between the concentrators (3) and the discharge force of the pump (9). Then, the refrigerant liquid reservoir (40) is immediately filled with the refrigerant liquid, and the pipe (4
The refrigerant liquid overflows from the refrigerant liquid reservoir (40) to the solution reservoir (38) of the generator (2) via 5). As a result, the absorption liquid concentrated in the generator (2) is diluted in a short time to prevent the absorption liquid from being crystallized, and the operation of the absorption heat pump can be safely continued. And the refrigerant liquid reservoir (41) of the evaporator (5)
When the liquid level inside drops and reaches the set safety level, the on-off valve (V) is closed by the signal from the liquid level controller (C ₂ ) and the normal operation is resumed.

When the absorption heat pump is stopped, the on-off valve (V) is opened by a switch (not shown) for a certain period of time prior to stopping the absorption liquid pump (10) to store the refrigerant liquid (41).
After the refrigerant liquid inside is blown to the solution reservoir (38) via the refrigerant liquid reservoir (40) of the condenser (3) by the discharge force of the pump (9) and the pressure difference and the drop, the absorption liquid is absorbed for a predetermined time. The driving to dilute is performed. As a result, crystallization of the absorbent after the operation is stopped is prevented.

Then, when the operation of the absorption heat pump is restarted, the refrigerant (40) from the refrigerant reservoir (40) of the condenser (3) which is almost full of the refrigerant liquid to the refrigerant reservoir (41) of the evaporator (5) is cooled by the pump (8). Liquid is sent. As a result, in a short time, the refrigerant liquid will be sprayed by the pump (9) to the heat supplier (25) of the evaporator (5),
Evaporation of the refrigerant starts early. When the evaporation of the refrigerant is started early, the pressure of the evaporation absorption stage (4) also rises quickly, and accordingly, the generator (2) is passed from the absorber (6) via the solution heat exchanger (7). The speed of the absorbing liquid flowing down to the water also increases, and the circulation of the absorbing liquid between the generator (2), the solution heat exchanger (7) and the absorber (6) is promoted. In addition, the refrigerant sump (40) of the condenser (3) during operation stop
Since the refrigerant liquid is filled with the refrigerant and is separated from the absorbing liquid, the time required for the absorbing liquid to reach a predetermined concentration also becomes short. Therefore, the time from the restart of the operation to the transition to the steady operation is shortened, and the start-up is accelerated.

As described above, in this type of absorption heat pump using the device of the present invention (hereinafter referred to as the present device), the refrigerant liquid sump (40) of the condenser (3) depends on the pressure difference, the head, and the discharge force of the pump (9). )
Since a predetermined amount of refrigerant liquid is blown into the absorbing liquid in the generator (2) via a short time, the concentration of the absorbing liquid circulating in the machine is kept below a predetermined value, and the absorbing liquid during operation is crystallized. Can be prevented in advance. Further, crystallization of the absorption liquid after the operation is stopped can be surely prevented. In FIG. 1, reference numeral (46) indicated by a chain double-dashed line is a liquid-sealed U-shaped tube that connects the vicinity of the uppermost portion of the refrigerant liquid reservoir (41) and the generator (2) to the refrigerant liquid reservoir ( 41)
This is for overflowing the liquid to the generator (2) side when the liquid level inside rises above the upper limit level set in the liquid level controller (C ₂ ) for some reason. Although not shown, a pipe with an on-off valve (not shown) may be connected to the pipe (44) and the generator (2) instead of the U-shaped pipe (46). Further, in this machine, the refrigerant liquid is almost filled and stored in the refrigerant liquid reservoir (40) of the condenser (3) during the suspension of operation, so that the refrigerant liquid reservoir (40) is retained during the suspension of operation. As compared with the conventional absorption heat pump of this type in which the refrigerant liquid is hardly stored in (41), the evaporation of the refrigerant in the evaporator (5) is started in a short time after restarting the operation, and the absorption liquid circulates quickly. As a result, the time required for the absorption liquid to reach a predetermined concentration is shortened and the start-up at the time of restarting the operation is accelerated.

In addition, in the embodiment shown in the figure, since the generation-condensation stage (1) is composed of two containers, the generator (2) and the condenser (3), the refrigerant liquid reservoir ( The flow path for the refrigerant liquid to overflow from the 40) to the solution reservoir (38) of the generator (2) is formed by the pipe (45), but the generation condensation stage (1) is composed of one container (not shown). It goes without saying that the pipe (45) is unnecessary in the case of doing so. Although the evaporative absorption stage (4) is arranged above the generating / condensing stage (1), the evaporative absorbing stage (4) may be arranged below the generating / condensing stage (1). The former arrangement is these steps
Although it is preferable because the speed at which the refrigerant liquid is blown is increased by the drop difference between (4) and (1), this drop is due to the pressure difference between these stages (4) and (1) and the discharge force of the pump (9). Since the force is smaller than that of the refrigerant liquid, the blowing speed of the refrigerant liquid is not so different between the former arrangement and the latter arrangement.

(F) Effects of the Invention As described above, the present invention, in this type of absorption heat pump, when the amount of the refrigerant liquid in the evaporator during operation increases to a set value, and the absorption liquid pump at the time of operation stop The refrigerant liquid in the evaporator is controlled to be blown into the absorbing liquid in the generator via the condenser for a predetermined amount of time in a short period of time before the stop of the, due to the pressure difference and the discharge force of the pump. Therefore, it is possible to prevent the crystallization of the absorbing liquid by keeping the concentration of the absorbing liquid during operation to a predetermined value or less, or to prevent the crystallization of the absorbing liquid after the operation is stopped.

Further, in this type of absorption heat pump provided with the control device of the present invention, since the refrigerant liquid is filled and stored in the refrigerant liquid reservoir of the condenser while the operation is stopped, the refrigerant is immediately evaporated in the evaporator after the operation is restarted. In addition, the time required to evaporate the absorption liquid to a predetermined concentration can be shortened as compared with the conventional absorption heat pump of this type, and the start-up when the operation is restarted can be accelerated.

[Brief description of drawings]

FIG. 1 is a schematic structural explanatory view showing an embodiment of a control apparatus for an absorption heat pump of this type according to the present invention, and FIG. 2 shows an example of an absorption liquid cycle when operating an absorption heat pump of this type. It is a Duhring diagram. (1) …… Generating condenser stage, (2) …… Generator, (3) …… Condenser,
(4) …… Evaporation absorption stage, (5) …… Generator, (6) …… Absorber,
(7) …… Solution heat exchanger, (8), (9), (10) …… Pump, (23)
...... Heater, (24) …… Cooler, (25) …… Heat supply, (26)…
… Heated device, (38) …… Solution reservoir, (40), (41) …… Refrigerant liquid reservoir, (44), (45) …… Pipe, (C ₂ ) …… Liquid level controller, (V ) ……
On-off valve.

Claims (1)

[Claims] 1. A salt solution is used as an absorbing liquid, a cooling fluid is caused to flow through a condenser, a heat source fluid is supplied to an evaporator and a generator, and a heated fluid having a temperature higher than that of the heat source fluid is taken out from the absorber. In an absorption heat pump configured by connecting a generator, a condenser, an evaporator, an absorber, etc. in a pipe, a refrigerant with an on-off valve between the discharge side of the refrigerant liquid pump for recirculating the refrigerant liquid of the evaporator to the evaporator and the condenser Connect with a liquid conduit, connect the generator and absorber with an absorbent liquid conduit with an absorbent pump,
A flow path for overflowing the refrigerant liquid is formed between the condenser and the generator, the opening / closing of the opening / closing valve is controlled based on the refrigerant liquid amount of the evaporator during operation of the absorption heat pump, and the absorption heat pump A control device for an absorption heat pump, comprising a mechanism for operating the refrigerant liquid pump for a predetermined time and stopping the opening / closing valve before stopping the absorption liquid pump when the operation is stopped.