JPH0583830B2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention extracts cold water and other cold fluids using the latent heat of vaporization of the refrigerant, while extracting hot water and other warm fluids using the latent heat of condensation of the refrigerant and the sensible heat of the absorption liquid. The present invention relates to a cold-temperature switching type double-effect absorption refrigerator (hereinafter referred to as this type of double-effect absorption refrigerator).

(B) Conventional technology The conventional technology for this type of dual-effect absorption chiller is to allow refrigerant vapor generated in a high-temperature generator during heating operation to bypass the condenser and flow to the evaporator, and to A device equipped with a conduit equipped with a solenoid valve or other on-off valve so that the absorbing liquid heated by the temperature bypasses the low-temperature generator and is distributed to the heat exchanger of the evaporator [e.g., JP-A-51-148848 No. Publication].

(c) Problems to be solved by the invention In this type of dual-effect absorption refrigerator, the resistance to the flow of refrigerant from the high-temperature generator side to the evaporator side by bypassing the condenser is smaller than that for the refrigerant flow via the generator and condenser to the evaporator side. In this type of conventional dual-effect absorption refrigerator,
During heating operation, most of the refrigerant vapor generated in the high-temperature generator flows directly to the evaporator, and very little refrigerant vapor flows to the low-temperature generator and condenser. tends to be lower than that of For this reason, the absorption liquid flowing from the high-temperature generator side to the low-temperature generator side via the solution heat exchanger tends to remain in the low-temperature generator, and the amount of absorption liquid in the absorber and high-temperature generator gradually decreases until it becomes liquid. There was a risk of cavitation of the pump and overheating of the high temperature generator.

In addition, in this type of dual-effect absorption refrigerator, the pressure difference between the high temperature generator side and the evaporator side during cooling operation is several hundred mmHg, so when switching from cooling operation to heating operation, the pressure difference is Allowable operating pressure for valves [This refers to the pressure at which a solenoid valve can open and close properly. For example, in a small-sized double-effect absorption refrigerator of this type, the allowable operating pressure is 0.05Kg (approximately 40mmH).
g) Solenoid valve is used. ] It is necessary to do the following. When switching from cooling operation to heating operation, the pressure difference is usually reduced by stopping the heating of the high temperature generator and performing dilution operation of the absorption liquid. Therefore, this kind of conventional double-effect absorption refrigerator has the problem that the dilution operation time has to be longer than necessary. Note that when a solenoid valve with a high allowable operating pressure is used, the valve becomes expensive and large.

In view of these problems, the present invention makes it possible to smoothly switch from cooling operation to heating operation in a short time by using a small and inexpensive solenoid valve or other on-off valve, and to reduce the absorption liquid during heating operation. The object of the present invention is to provide a dual-effect absorption refrigerator of this type that can prevent excessive stagnation in the low-temperature generator, thereby preventing cavitation of the solution pump and overheating of the high-temperature generator.

(d) Means for Solving the Problems The present invention, as a means for solving the above-mentioned problems, provides a U with a solenoid valve and other cooling/heating switching on/off valves provided in this type of dual-effect absorption refrigerator. The downstream side of the on-off valve in the U-shaped conduit is connected to the low-temperature generator by a conduit, and the U-shaped conduit is connected to the discharge side of the solution pump with a thin tube with an orifice to prevent overflow. The structure is such that it is connected to the solution reservoir of the absorber through a thin tube.

(e) Function In this type of dual-effect absorption refrigerator according to the present invention, the pressure difference at the inlet and outlet of the solenoid valve and other cooling/heating switching on/off valves is the difference between the pressure on the low temperature generator side and the pressure on the high temperature generator side. Compared to conventional systems, which are governed by the difference between the pressure on the evaporator side and the pressure on the high-temperature generator side, the above pressure difference can be used to switch between cooling and heating in a short time during absorption liquid dilution operation. It has the function of keeping the pressure below the allowable operating pressure of the valve. Therefore, the cooling operation can be quickly switched to the heating operation. In addition, during heating operation, a larger amount of refrigerant vapor flows from the high-temperature generator side to the low-temperature generator side via the pipe connecting the U-shaped pipe and the low-temperature generator than in conventional systems, increasing the pressure inside these devices. Since the pressure is maintained at approximately the same level, the pressure on the low temperature generator side will not be lower than that on the evaporator side.
Therefore, during heating operation, a large amount of absorption liquid does not remain in the low temperature generator, and cavitation of the solution pump and overheating of the high temperature generator are prevented.

Moreover, in this kind of double-effect absorption refrigerator according to the present invention, the U-shaped pipe is connected to the discharge side of the solution pump through a thin tube with an orifice, and connected to the solution reservoir of the absorber through an overflow thin tube. During cooling operation, the low-temperature generator and absorber are liquid-sealed with a U-shaped pipe to maintain the required pressure difference between these devices, and the evaporator heat exchanger is It has the effect of preventing the absorption liquid from scattering.
Therefore, good cooling operation can be performed.

(F) Embodiment The drawing is a schematic structural diagram showing an embodiment of this type of dual-effect absorption refrigerator according to the present invention. In the figure, 1 is a high temperature generator, 2 is a gas-liquid separator, and 3
is a generation condenser consisting of a low temperature generator 4 and a condenser 5; 6 is an evaporative absorber consisting of an evaporator 7 and an absorber 8; 9 and 10 are low temperature and high temperature solution heat exchangers;
1 is a bubble pump, 12 is a solution pump, and these are a liquid pumping pipe 13, and pipes 14, 15, 16, through which absorption liquid flows.
17, pipes 18, 19, 20, 2 to which the absorption liquid is sent
1. Pipes 22, 23, 24, 25, 2 through which refrigerant flows
6 and 27 to form a circulation path for refrigerant (water) and absorption liquid (lithium bromide aqueous solution) similar to that of a conventional dual-effect absorption refrigerator of this type.

28 is a refrigerant vapor and absorption liquid bypass pipe connecting the gas-liquid separator 2 and the evaporative absorber 6, and this pipe is equipped with a solenoid valve V having an allowable operating pressure of about 0.05 kg/cm ² . A U-shaped portion 29 is formed downstream of the solenoid valve. Note that the valves provided in the bypass conduit 28 are not limited to electromagnetic valves, and various types of on-off valves such as electric valves and those operated by air pressure can be used.

In addition, 30 is a low temperature generator 4 and a bypass pipe 2
This pipe is connected to the downstream side of the electromagnetic valve V of No. 8, and the open end of this pipe on the low temperature generator 4 side is located above the bottom wall of the low temperature generator 4. Further, 31 is a thin tube with an orifice O ₁ that connects the U-shaped part 29 of the bypass pipe 28 and the pipe 19 on the discharge side of the solution pump 12, and 32 is a thin tube with an orifice O 1 that connects the U-shaped part 29 of the bypass pipe 28 with the evaporator absorber 6 of the bypass pipe 28. This is an overflow thin tube that connects the side wall of the U-shaped portion 29 located below the connection opening 33 of the absorber 8 and the solution reservoir 34 of the absorber 8 to allow the absorption liquid to overflow.

35 is the burner of the high temperature generator 1, 36 is the heater of the low temperature generator 4, 37 and 38 are the coolers of the condenser 5 and absorber 8, respectively, 39 is the heat exchanger of the evaporator 7, 40, 41 , 42 are coolers 38, 37
The pipes 43 and 44 are pipes through which cold water or hot water flows, which connect the air conditioning unit (not shown) and the heat exchanger 39 in series. In addition, 4
5 is a heating coil for the bubble pump 11, and 46
is a liquid receiver provided at the bottom of the evaporator 7.

47 is a U-shaped absorption liquid overflow pipe provided between the low temperature generator 4 and the absorber 8;
9 through a thin tube 48 with an orifice _O2 . Further, 49 is a pipe with a valve V ₀ connecting the pipe 26 and the solution reservoir 34, and 50 and 51 are a refrigerant liquid dispersion device and an absorption liquid dispersion device, respectively. Furthermore, 52, 53, and 54 are eliminators provided in the gas-liquid separator 2, the generation condenser 3, and the evaporator-absorber 6, respectively.

Next, an example of the operation of a dual-effect absorption refrigerating machine (hereinafter referred to as this machine) of the cooling/heating switching type (hereinafter referred to as this machine) configured as described above will be explained. I will explain this by comparing it with the machine (called a machine).

During cooling, the electromagnetic valve V is closed and the operation is performed in the same way as in the conventional machine, and cold water is obtained from the heat exchanger 39 by forming a dual-effect absorption refrigeration cycle by circulating refrigerant and absorption liquid. During cooling, the internal pressure of the high-temperature generator 1, gas-liquid separator 2, generation condenser 3, and evaporator-absorber 6 is 600 to 700 mmH, respectively, as in the conventional model.
g, 600-700mmHg, 55-65mmHg, 5-7mmH
The engine can continue to operate while being maintained at around g. In addition, in this machine, during cooling operation, the absorption liquid sent to the U-shaped part 29 of the bypass pipe 28 via the capillary tube 31 to seal the gap between the generation condenser 3 and the evaporator absorber 6 is transferred to the capillary tube. The solution is returned to the solution reservoir 34 via 32. Therefore, the absorption liquid is not sprayed onto the heat exchanger 39, and good refrigeration performance is exhibited.

When switching from cooling operation to heating operation,
Prior to this, the heating of the high temperature generator 1 is stopped and the absorption liquid is circulated within the machine to perform a dilution operation of the absorption liquid. By performing such dilution operation for about 10 minutes, the concentration and temperature of the absorption liquid circulating in the machine decrease, and the pressure difference between the gas-liquid separator 2 and the generation condenser 3, and the difference between the gas-liquid separator 2 and the evaporative absorption. The pressure difference between the vessels 6 will be about 20 mmHg and 50 mmHg, respectively. In other words, in this machine, the pressure difference at the inlet and outlet of the solenoid valve V becomes approximately 20 mmHg in about 10 minutes after starting dilution operation, and the allowable operating pressure of the valve [0.05 kg/
cm ² ] or less. On the other hand, in conventional machines in which a force equivalent to the pressure difference between the gas-liquid separator 2 and the evaporator-absorber 3 is applied to the inlet and outlet of the valve, the pressure difference has not yet reached the allowable operating pressure of the solenoid valve. A dilution operation of about 25 minutes is required to achieve the pressure difference below this. Therefore, in this machine, compared to conventional machines, the solenoid valve V is closed in a short time after starting dilution operation.
can be opened.

Then, open the solenoid valve V, and
The heating is restarted, and the supply of cooling water to the coolers 38 and 37 is stopped, and the operation is started. As a result, as in the conventional machine, the liquid seal in the bypass pipe 28 is broken, and the absorption liquid heated in the high temperature generator and the generated refrigerant vapor flow into the evaporator absorber 6 via this pipe. The temperature of water in the heat exchanger 39 is raised by the latent heat of condensation of the refrigerant vapor and the sensible heat of the absorption liquid distributed in the heat exchanger 39, and hot water is supplied to an air conditioning unit (not shown). In other words, it switches to heating operation. Further, after switching to heating operation, refrigerant vapor flows from the gas-liquid separator 2 to the generation condenser 3 side through the bypass pipe line 28 and the pipe line 30, and these devices are almost equalized in pressure. Therefore, in this machine, unlike the conventional machine, there is almost no possibility that the absorption liquid is unevenly distributed in the low temperature generator 4, causing cavitation of the solution pump 12 or overheating of the high temperature generator 1.

In addition, if absorbing liquid leaks from the closed solenoid valve V during cooling operation of this machine, the pressure on the outlet side of the solenoid valve V in this machine is close to that on the generation condenser 3 side, and the pressure on the evaporator absorber 6 Since it is not as low as the conventional model that is similar to the one on the side, there is no drawback that leaked absorption liquid self-flashes and crystallizes near the valve seat. Therefore, in this machine, even if absorbing liquid leaks from the solenoid valve V, the solenoid valve V can be switched open and closed more safely than the conventional machine.

Furthermore, in this machine, the cooler 38 of the absorber 8
When the configuration is such that hot water is extracted from the U-shaped portion 29 of the bypass pipe 28 and the pipe 30,
The pipe 47 is not necessarily used because it serves both as a pipe for overflowing the absorption liquid and as a pipe for liquid sealing to maintain the required pressure difference between the generation condenser 3 and the evaporative absorber 6 during cooling operation. You don't have to prepare.

(G) Effects of the Invention The present invention is a cold-temperature switching type double-effect absorption refrigerating machine configured as described above, which includes an on-off valve that connects the high-temperature generator to the low-pressure side container by bypassing the condenser and low-temperature generator. Connect the U-shaped pipe with the on-off valve downstream of this U-shaped pipe to the low temperature generator, and the thin pipe from the U-shaped pipe to the absorption liquid pipe on the discharge side of the solution pump. and an overflow tube so that the absorption liquid flows from the downstream side of the U-shaped part of the U-shaped pipe to the absorber. Using a small and inexpensive on-off valve with a low allowable operating pressure, it has the effect of quickly switching from cooling to heating operation, and also reduces the retention of absorption liquid in the low-temperature generator during heating operation. This is effective in preventing cavitation of solution pumps and overheating of high temperature generators. Furthermore, during cooling operation, the generation condenser and evaporative absorber are liquid-sealed with a U-shaped bypass pipe to maintain the required pressure difference between these devices. The absorption liquid sent to the channel is returned to the absorber and does not flow to the evaporator side, so it exhibits good refrigeration performance.

[Brief explanation of the drawing]

The drawing is a schematic structural diagram showing an embodiment of this type of dual-effect absorption refrigerator according to the present invention. 1... High temperature generator, 2... Gas-liquid separator, 3...
Generation condenser, 4... Low temperature generator, 5... Condenser,
6... Evaporative absorber, 7... Evaporator, 8... Absorber, 9, 10... Low temperature, high temperature solution heat exchanger, 12
... Solution pump, 19 ... Pipe, 28 ... Bypass pipe line, 29 ... U-shaped part, 31, 32 ... Thin tube, 34 ... Solution reservoir, 39 ... Heat exchanger, O ₁
... Orifice, V ... Solenoid valve.

Claims (1)

[Claims] 1. A high-temperature generator, a low-temperature generator, a condenser into which the refrigerant vapor generated by the low-temperature generator and the high-temperature generator flows and condenses, a low-pressure side container that houses an evaporator and an absorber, and an absorber in this low-pressure side container. an absorption liquid pipe line from the high temperature generator to the high temperature generator with a solution pump; a U-shaped pipe line with an on-off valve from the high temperature generator bypassing the condenser and the low temperature generator to the low pressure side container; and this U-shaped pipe. A pipe line from the downstream side of the on-off valve to the low temperature generator, and a narrow pipe from the U-shaped pipe line to the absorption liquid pipe line on the discharge side of the solution pump, and downstream of the U-shaped part of the U-shaped pipe line. A cold/temperature switching type double-effect absorption refrigerator characterized by an overflow capillary connected so that the absorption liquid flows from the side to the absorber.