JPH09236352A - Hot water absorption absorption refrigerator - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To continuously dissipate exhaust heat of an engine at a low cost even when the load of a hot water-fired absorption refrigerator constituting a cogeneration system is reduced. A liquid refrigerant pipe connecting a condenser 2 and an evaporator 3 is provided with a refrigerant bypass proportional valve 10 having outlet ports A and B, and the outlet port A is used as a refrigerant spraying device of the evaporator 3 and an outlet port. B is connected to the solution spraying device of the absorber 4, and the openings of the outlet ports A and B are controlled based on the temperature Th of the heat source water supplied to the regenerator and the cold water outlet temperature Tc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water-fired absorption refrigerator having a regenerator heated with hot water, and more particularly to a hot water-fired absorption refrigerator in which hot water uses engine exhaust heat as a heat source.

[0002]

2. Description of the Related Art A hot water-fired absorption refrigerating machine equipped with a regenerator heated by hot water using engine exhaust heat as a heat source is incorporated into, for example, the cogeneration system disclosed in JP-A-6-159848 shown in FIG. There are some The cogeneration system shown in FIG. 4 is an engine 21 that drives a generator 22, a hot water absorption that is connected to the engine 21 by a heat source water circuit pipe 30 having heat source water control valves 26, 27 and a heat source water three-way valve 29. Heat is exchanged between the cooling tower 25, the heat source water circuit tube 30 and the cooling water circuit tube 31 which are connected to the refrigerator 24 and the hot water-fired absorption refrigerator 24 by the cooling water circuit tube 31 with the cooling water control valve 28 interposed. Heat dissipation heat exchanger 2
3 is included.

[0003]

In such a cogeneration system, the hot water-fired absorption refrigerator 24 is used.
When the load decreases, the cooling water control valve 28 controls the flow of the cooling water so that the heat source water three-way valve 29 connects the heating fluid outlet side of the heat radiating heat exchanger 23 to the engine 21. The heat source water control valve 26 is closed and the heat source water control valve 27 is opened by opening the heat source water control valve 27. In this way, the heat source water (heat exhaust heat) from the engine 21 is absorbed in the absorption refrigerator 24.
Is bypassed to the heat radiating heat exchanger 23, where heat is exchanged with the cooling water, the heat is radiated in the absorption refrigerator cooling tower 25, and the operation of the engine 21 is continued.
Further, as shown in FIG. 5, a method of suppressing a temporary rise in the engine cooling water temperature generated at this time was also required.

In the system as described above, the heat radiating heat exchanger 23 must be installed for radiating the exhaust heat of the engine, which is a factor of increasing the cost of the system.

An object of the present invention is to reduce the load on a hot water-fired absorption refrigerator that constitutes a cogeneration system,
It is to continuously dissipate engine exhaust heat at low cost.

[0006]

A first means of the present invention is as follows.
In order to achieve the above problem, in a regenerator heated by hot water using engine exhaust heat as a heat source, a condenser, an evaporator and an absorber and a hot water-fired absorption refrigerator that forms an absorption refrigeration cycle by pipe connection, A branch pipe is provided in the liquid refrigerant pipe for guiding the liquid refrigerant from the condenser to the evaporator, the branch pipe is connected to the upper part of the absorber, and a flow rate control means for controlling the flow rate of the liquid refrigerant flowing through the branch pipe is provided. It is characterized by

When the load on the refrigerator decreases, a part of the liquid refrigerant is guided to the upper part of the absorber by the flow rate control means to reduce the evaporation amount of the liquid refrigerant in the evaporator, thereby reducing the heat input amount in the regenerator. Without doing so, it is possible to avoid a situation in which the heat medium (for example, cold water) flowing in the evaporation coil is excessively cooled and frozen. The liquid refrigerant introduced to the upper part of the absorber is the absorbing solution (concentrated solution) also introduced to the upper part of the absorber.
Is mixed with the mixture to form a dilute solution and flows down to the bottom of the absorber. The sensible heat generated during the mixing is removed by the cooling water flowing through the cooling water coil of the absorber. Therefore, even if the load of the hot water-fired absorption refrigerator that uses the exhaust heat of the engine as a heat source is reduced, the operation of the engine can be continued regardless of the load.

The second means of the present invention is a hot water-fired absorption refrigeration system in which a regenerator, a condenser, an evaporator and an absorber, which are heated by hot water whose heat source is engine exhaust heat, are connected by piping to form an absorption refrigeration cycle. In the machine, in the liquid refrigerant pipe connecting the condenser and the evaporator, at least two flow outlets for distributing the liquid refrigerant to the two outlets are provided, and one outlet is connected to the evaporator and the other outlet is connected. It is characterized by being connected to the upper part of the absorber.

When the load on the refrigerator decreases, a part of the liquid refrigerant is guided to the upper part of the absorber by the flow distribution means and the amount of the liquid refrigerant introduced to the evaporator is reduced to reduce the evaporation amount of the liquid refrigerant in the evaporator. By doing so, it is possible to avoid a situation in which the heat medium (for example, cold water) flowing in the evaporation coil is excessively cooled and frozen without reducing the heat input amount in the regenerator. Therefore, even if the load of the hot water-fired absorption refrigerator that uses the engine exhaust heat as a heat source decreases, the engine operation can be continued regardless of the load.

The flow rate distribution means is controlled such that the total of the flow passage cross-sectional areas to the two outlets is always substantially equal to the flow passage cross-sectional area when the flow passage to one of the outlets is fully opened. Good to do. In addition, the flow rate distribution means is configured such that the cold water outlet temperature T
It is desirable that the temperature be controlled based on c and the temperature Th of the hot water that heats the regenerator.

The chilled water outlet temperature Tc is controlled by the flow distribution means.
When the temperature falls below the preset first temperature T ₁ , the outlet connected to the absorber starts to open, and when the cold water outlet temperature Tc reaches the preset second temperature T ₂ , the outlet is fully opened. It is better to Further, the flow rate distribution means may immediately open the outlet connected to the absorber when the chilled water outlet temperature Tc falls below the preset third temperature T ₃ .

If the amount of heat input to the regenerator does not change, the above procedure may be used. However, if the temperature of the heat source water flowing into the regenerator changes, the flow rate distribution means should be controlled based only on the chilled water outlet temperature Tc. It causes inconvenience. Therefore, it is preferable that the flow rate distribution unit changes the preset first temperature T ₁ and second preset temperature T ₂ based on the temperature Th of the hot water that heats the regenerator.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The hot water-fired absorption refrigerating machine shown in FIG. 1 was connected to a regenerator 1 in which an absorption solution contained in engine cooling water (heat source water) (not shown) is heated, and to the regenerator 1 via a refrigerant vapor passage. A condenser 2, an evaporator 3 connected to the condenser 2 via a refrigerant bypass proportional valve 10 which is a flow distribution means, an absorber 4 connected to the evaporator 3 via a refrigerant vapor passage, and an absorber 4 Solution circulation pump 6 arranged by connecting the suction side to the bottom, solution heat exchanger 5 arranged by connecting the heated fluid entering side to the discharge side of the solution circulation pump 6, the engine and the regenerator A heat source water circuit pipe 11 arranged in a circulation loop between the two to circulate the heat source water.
A cold water pipe 12 arranged in a circulation loop between the evaporation coil installed in the evaporator 3 and a cold water load to circulate a heat medium (cold water); and a regenerator inlet of the heat source water circuit pipe 11. Heat source water temperature sensor 3 for detecting and outputting heat source water temperature Th
4, the cold water outlet temperature sensor 33 that detects and outputs the cold water temperature Tc at the evaporator outlet of the cold water pipe 12, and the refrigerant bypass proportional valve 10 with the outputs of the heat source water temperature sensor 34 and the cold water outlet temperature sensor 33 as inputs. Controller 35 for controlling
And is configured.

The bottom of the regenerator 1 and the heating fluid inlet side of the solution heat exchanger 5 are connected by a concentrated solution pipe 36, and the heating fluid outlet side of the solution heat exchanger 5 is connected to a concentrated solution spraying device installed in the upper part of the absorber. It is connected. The refrigerant bypass proportional valve 10 is a three-way valve having one inlet port and two outlet ports A and B. The inlet port is connected to the condenser 2 by the liquid refrigerant pipe 38, and the outlet port A is an evaporator. It is connected to a liquid refrigerant spraying device installed in the upper part, and an outlet port B is connected to the concentrated solution spraying device installed in the upper part of the absorber through a branch pipe 37. The refrigerant bypass proportional valve 10 is configured to open and close with the opening degrees of the two outlet ports associated with each other, and the flow passage cross-sectional areas when the respective outlet ports are fully opened are equal to each other. In addition, the total opening of the two outlet ports is always 100%.
The operating position of the refrigerant bypass proportional valve 10 is the controller 3
5 is input.

When the hot-water-fired absorption refrigerator having the above-described structure is operated at full load with the heat-source water temperature at the planned value, the controller 35 sets the refrigerant bypass proportional valve 10 and the opening of the outlet port A to 100. %, The opening of the outlet port B is maintained at 0%. In this state, the cold water outlet temperature Tc
Keeps the planned temperature. From this state, when the cold water load on the absorption refrigerator is reduced while the output state of the engine remains the same, the liquid refrigerant supplied to the evaporator becomes excessive, and the cold water outlet temperature Tc drops. When the cold water temperature becomes lower than the preset first temperature T ₁ , the controller 35
The refrigerant bypass proportional valve 10 is operated to open the outlet port B by a predetermined amount and close the opening degree of the outlet port A by the same amount. When the cold water outlet temperature Tc further drops to the preset second temperature T ₂ , the outlet port B is fully opened and the outlet port A is opened.
Fully close. When the cold water outlet temperature Tc is between T ₁ and T ₂ , the opening degree of the outlet port B may be opened or closed stepwise or by stepwise proportional control or proportional integral control.

As the first temperature T ₁ and the second temperature T ₂ ,
When water is used as the heat medium circulated to the load side, for example, if the temperature of the heat source water is 80 ° C., a value of 7 ° C. or 3 ° C. is appropriately set.

By opening the outlet port B, the amount of the liquid refrigerant supplied to the evaporator 3 is reduced and the refrigerating capacity is lowered. On the other hand, the liquid refrigerant introduced to the concentrated solution spraying device of the absorber through the outlet port B is mixed with the concentrated solution there to reduce the concentration and then sprayed on the cooling water coil. Therefore, the absorbing power is also reduced, and the cooling water temperature is prevented from lowering. As a result, the refrigerating capacity of the absorption refrigerator is reduced to a refrigerating capacity commensurate with the reduction of the cold water load. The amount of heat input to the regenerator in this state is the same as that at full load, and there is no obstacle to removal of engine exhaust heat.

With this control, when the cold water load is zero, that is, when the hot water-fired absorption refrigerator does not work, but the hot exhaust heat of the engine must be dissipated, the refrigerant bypass proportional valve 10 is fully opened, and the condenser is closed. The operation is to introduce all of the liquid refrigerant supplied from the absorber to the absorber and mix it into the concentrated solution.

In the above example, the temperature Th of the heat source water is not changed, but if the temperature Th of the heat source water supplied from the engine is high, even if the flow rate of the circulated heat source water per hour is the same. Since the amount of heat input to the regenerator increases, more refrigerant evaporates, and a more concentrated concentrated solution is produced, the refrigerating capacity of the absorption chiller tends to increase.
Therefore, the opening degree of the outlet port B of the refrigerant bypass proportional valve 10 is corrected and controlled by the temperature Th of the heat source water. FIG. 2 shows an example of the relationship between the cold water outlet temperature Tc and the opening degree of the outlet port B with the cold water outlet temperature Tc as the horizontal axis and the opening degree of the outlet port B as the vertical axis, and using the temperature Th of the heat source water as a parameter. Is shown. As is clear from the figure,
As the temperature Th of the heat source water becomes higher, the cold water outlet temperature T _{1 at} which the outlet port B starts to open and the cold water outlet temperature T _{2 at} which the outlet port B is fully opened become higher.

FIG. 3 shows an example of a procedure for controlling the chilled water outlet temperature T _{1 at} which the outlet port B starts to open and the chilled water outlet temperature T ₂ at which the outlet port B fully opens according to the temperature Th of the heat source water. Show. In this case, the controller 35 stores in advance a table showing the first temperature T ₁ and the second temperature T ₂ corresponding to the temperature Th of the heat source water, as shown in FIG. The first temperature T ₁ and the second temperature T ₂ corresponding to the temperature Th of the heat source water are taken out. Next, the cold water outlet temperature Tc is detected, and the opening degree of the outlet port B is determined using the detected cold water outlet temperature Tc, the first temperature T ₁ and the second temperature T ₂ . Opening of the outlet port B (%) is calculated, for example, by _{(Tc-T 1) ÷ (} T 2 -T 1) × 100.
Although FIG. 3 does not mention the control of the opening of the outlet port A, the opening of the outlet port A is automatically (100−exit port B if the opening of the outlet port B is controlled.
The opening degree is controlled so that

[0021] In the above example, has been described as controlling the stepwise or steplessly based the opening of the outlet port B to a temperature Th of the cold water outlet temperature Tc and the heat source water, for example, the T _1, T ₂ A third temperature T ₃ may be set in the middle, and when the cold water outlet temperature Tc falls below the _third temperature T ₃ , the outlet port B may be fully opened immediately. When this method is used when the chilled water load does not change stepwise but is limited to change to 0% or 100%, control can be simplified.

[0022]

According to the present invention, even if the cold water load fluctuates, the heat input to the regenerator can be continued while the absorption refrigerator is operating, so that the engine power generation load can be operated as a priority cogeneration system. Also, since a heat exchanger for heat radiation is not required, an inexpensive and simple cogeneration system can be constructed.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a graph showing an example of the present invention.

FIG. 3 is a control procedure diagram showing another embodiment of the present invention.

FIG. 4 is a system diagram showing an example of a conventional technique.

FIG. 5 is a system diagram showing another example of the conventional technique.

[Explanation of symbols]

1 Regenerator 2 Condenser 3 Evaporator 4 Absorber 5 Solution heat exchanger 6 Solution circulation pump 7 Solution diversion valve 8 Concentrated solution pipe 9 Cooling water coil 10 Refrigerant bypass proportional valve 11 Heat source water circuit pipe 12 Cold water pipe 21 Engine 22 Power generation Machine 23 Radiation heat exchanger 24 Absorption refrigerator 25 Cooling tower 26, 27 Heat source water control valve 28 Cooling water control valve 29 Heat source water three-way valve 30 Heat source water circuit pipe 31 Cooling water circuit pipe 32 Thermometer 33 Cold water outlet temperature sensor 34 Heat source water temperature sensor 35 Controller 36 Concentrated solution pipe 37 Branch pipe 38 Liquid refrigerant pipe

Claims (8)

[Claims] 1. A hot water-fired absorption refrigerator in which an absorption refrigeration cycle is formed by connecting a regenerator 1, a condenser 2, an evaporator 3 and an absorber 4 which are heated by hot water using engine exhaust heat as a heat source, to form an absorption refrigeration cycle. A branch pipe 37 is provided in a liquid refrigerant pipe 38 that guides the liquid refrigerant from the condenser 2 to the evaporator 3, and the branch pipe 37 is connected to the upper part of the absorber 4 and the flow rate of the liquid refrigerant flowing through the branch pipe 37 is controlled. A hot water-fired absorption refrigerating machine, which is provided with a flow rate control means 10 for controlling. 2. A hot water-fired absorption refrigerating machine which forms an absorption refrigeration cycle by connecting a regenerator 1, a condenser 2, an evaporator 3 and an absorber 4 which are heated by hot water whose heat source is engine exhaust heat, to form an absorption refrigeration cycle. A liquid refrigerant pipe 38 connecting the condenser 2 and the evaporator 3 is provided with a flow rate distribution means 10 for flowing the liquid refrigerant separately to at least two outlets A and B, and one outlet A is connected to the evaporator 3. In addition, the other outlet B is connected to the upper part of the absorber 4, and a hot water-fired absorption refrigerator is characterized. 3. The flow rate distribution means 10 has two outlets A and B.
The flow path cross-sectional area to the outlet is controlled so as to be substantially equal to the flow path cross-sectional area when the flow path to one outlet is fully opened. Hot water fired absorption refrigerator. 4. The chilled water outlet temperature Tc of the flow rate distribution means 10
The hot water-fired absorption refrigerator according to claim 2 or 3, which is controlled on the basis of the temperature Th of the hot water for heating the regenerator 1. 5. The cold water outlet temperature Tc of the flow distribution means 10
When the temperature falls below a preset first temperature T ₁ , the outlet B connected to the absorber 4 begins to open, and the chilled water outlet temperature Tc fully opens the outlet B at the preset second temperature T _2. The hot water-fired absorption refrigerator according to claim 4, wherein 6. The chilled water outlet temperature Tc of the flow distribution means 10
The hot water-fired absorption refrigerating machine according to claim 4, wherein when the temperature falls below a preset third temperature T ₃ , the outlet B connected to the absorber 4 is fully opened. 7. The flow rate distribution means 10 changes the preset first temperature T ₁ and second preset temperature T ₂ in accordance with the temperature Th of the hot water that heats the regenerator 1. The hot water-fired absorption refrigerator according to any one of claims 4 to 6. 8. An absorption refrigeration cycle is formed by connecting a regenerator 1, a condenser 2, an evaporator 3 and an absorber 4 which are heated by hot water whose heat source is engine exhaust heat, to form an absorption refrigeration cycle, and the condenser and the evaporator. The liquid refrigerant pipe 38 connecting to the above is provided with a flow rate distribution means 10 for distributing the liquid refrigerant separately to the outlets A and B which can adjust at least two openings and the total of both openings is always 100%. In a method of controlling a hot water-fired absorption refrigerator in which an outlet A is connected to an evaporator 3 and an outlet B is connected to an upper portion of an absorber 4, a temperature Th of the hot water is detected, and the detected temperature Th and a predetermined table Based on the first temperature T ₁ and the second temperature
Temperature T ₂ is selected, the cold water temperature Tc at the outlet of the evaporator 3 is detected, the temperature T ₁ is compared with the temperature Tc, and when Tc> T ₁ , the outlet B is closed and the temperature Th of the hot water is detected. The above procedure is repeated, and when Tc> T ₁ is not satisfied, the temperature T ₂ and the temperature Tc
When Tc <T ₂ , the procedure for detecting the temperature Th of the hot water after the outlet B is fully opened is repeated. If Tc <T ₂ is not satisfied, the opening degree of the outlet B is determined based on T ₁ , T ₂ and Tc. Is calculated, the opening degree of the outlet B is changed to the calculated opening degree, and then the procedure for detecting the temperature Th of the hot water is repeated, and the method for controlling the hot water absorption refrigerator is characterized.