JP2003148829A - Cogeneration type absorption refrigerating machine and its operation control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cogeneration type absorption refrigerating machine and its control method, capable of realizing high performance and low cost. SOLUTION: This cogeneration type absorption refrigerating machine comprises a power generating device having an engine as a driving source, and an absorption refrigerating machine comprising a high pressure regenerator for absorbing and dissolving a refrigerating gas evaporated by an evaporator into a solution of high concentration in an absorber, and heating the diluted solution from the absorber by a burner to regenerate the same as a solution of high temperature and high concentration, and returning the solution of high concentration to the absorber. The exhaust heat of the engine is also used as a heating source of the high pressure regenerator. A fuel amount determining circuit 70a is mounted for calculating a fuel control valve opening command value outputted to a fuel control valve 43, by subtracting cooling or heating performance given by the exhaust heat of the engine, from the fuel amount of the burner corresponding to the cooling and heating load of the absorption refrigerating machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cogeneration type absorption refrigerating machine capable of simultaneously performing power generation and cooling / heating, and particularly, it efficiently operates by effectively utilizing exhaust heat of an engine for driving the generator. The present invention relates to a cogeneration-type absorption refrigerator and a control method thereof.

[0002]

2. Description of the Related Art A cogeneration absorption refrigerating machine is a device capable of simultaneously performing power generation by an engine-driven generator and cooling and heating by an absorption refrigerating machine, and uses exhaust heat of an engine as a heat source for the absorption refrigerating machine. Thus, it is possible to reduce the fuel consumption required to heat the dilute solution of the absorbing liquid (generally lithium bromide) to form a concentrated solution. Therefore, the cogeneration-type absorption refrigerator has an advantage that energy can be saved with high efficiency as compared with a normal absorption refrigerator.

An absorption refrigerator is a refrigerator using water as a refrigerant, a lithium bromide solution as an absorbent, and gas fuel, oil fuel, or steam as a heating energy source. This absorption refrigerator has an evaporator, an absorber, a regenerator, and a condenser as main components, and the inside of the evaporator and the absorber is maintained in a high vacuum (absolute pressure 6 to 7 mmHg). .

In the evaporator, the liquid refrigerant (water) sent by the refrigerant pump is sprayed toward the evaporator tube through which cold water (for example, 12 ° C.) flows, so that the liquid refrigerant is heated and the refrigerant vapor ( Gas). In other words, since the evaporator is a high-vacuum container, liquid water (refrigerant) boils at around 4 to 6 ° C and evaporates and evaporates. Therefore, even cold water at 12 ° C can be used as heat source water. You can do it.

The temperature of the cold water flowing in the evaporator tube decreases by the latent heat of vaporization given to the liquid refrigerant (water) (for example, 7 ° C.).
Then it goes out of the evaporator. The chilled water whose temperature has been lowered (for example, to 7 ° C.) is sent to a cooling device or the like (cooling load) of a building, and is used for cooling as a cold heat source for cooling by exchanging heat with the air in the room. The cold water used for cooling rises in temperature (for example, reaches 12 ° C.) and flows into the evaporator tube of the evaporator again.

In the absorber, the refrigerant vapor generated in the evaporator is absorbed by the lithium bromide solution. The lithium bromide solution which has absorbed water and has a low concentration (hereinafter referred to as "diluted lithium bromide solution") is collected at the bottom of the absorber. In this absorber, the latent heat of condensation when the refrigerant vapor is absorbed by the lithium bromide solution and changes from gas (water vapor) to liquid (water) and when the concentration of the lithium bromide solution absorbs water and becomes thin Since heat of dilution is generated, these heats are removed by cooling water (which is circulated in a system different from the above "cold water"). Since the lithium bromide solution has a partial vapor pressure of water lower than that of saturated vapor of water, it is highly hygroscopic and is a suitable substance for absorbing refrigerant vapor.

In the regenerator, the diluted lithium bromide solution sent from the absorber is heated by a burner or the like. For this reason,
A part of the refrigerant in the dilute solution of lithium bromide is vaporized, and the solution becomes a concentrated lithium bromide solution (hereinafter, referred to as "concentrated lithium bromide solution"). The concentrated lithium bromide solution whose concentration has been increased to the original state in this way is sent to the absorber and absorbs the refrigerant vapor again. On the other hand, the evaporated refrigerant vapor is sent to the condenser.

In an actual absorption refrigerating machine, a double-effect absorption refrigerating machine having a regenerator arranged in two stages is adopted for the purpose of increasing thermal efficiency and reducing heating energy.
In this double-effect absorption refrigerator, as a regenerator, a high-pressure regenerator that heats the dilute solution of lithium bromide by burning the supplied fuel or by introducing high-temperature steam, and a high-pressure regenerator And a low-pressure regenerator that heats the dilute lithium bromide solution using the high-temperature refrigerant vapor generated in the reactor as a heating source.

In the condenser, the refrigerant vapor sent from the regenerator is condensed and liquefied by cooling it with cooling water. The water condensed by this condenser is again supplied to the evaporator as a liquid refrigerant (water).

In this manner, in the absorption refrigerator, the refrigerant (water) changes (water-steam-water) (phase change), and the lithium bromide solution changes from concentrated solution-diluted solution-concentrated solution. (Change in concentration). The absorption chiller produces cold water by the latent heat of vaporization of water during the above-described phase change (refrigerant) and concentration change (lithium bromide solution), and absorbs water vapor by the absorption capacity of the lithium bromide solution. Is a device for repeatedly performing the above in a high vacuum closed system.

In such an absorption refrigerating machine, the amount of fuel or steam supplied to the high-pressure regenerator is increased to increase the amount of heating and the concentration of the lithium bromide solution is made thicker, whereby the cold water flowing out of the evaporator is increased. The temperature can be lowered. Conversely, the amount of fuel and steam supplied to the high-pressure regenerator can be reduced to reduce the amount of heating and reduce the concentration of the lithium bromide solution to raise the temperature of the cold water exiting the evaporator. . In this way, by adjusting the concentration of the lithium bromide solution, the temperature of the cold water is controlled and the temperature of the cold water leaving the evaporator is maintained at the set temperature (for example, 7 ° C).

In the cogeneration type absorption refrigerator, an engine-driven generator is installed together with the absorption refrigerator described above, and exhaust heat of the engine that drives this generator is used as a heat source for the high-pressure regenerator. The amount of fuel used in the high pressure regenerator can be saved.

[0013]

By the way, in the above-mentioned conventional cogeneration type absorption refrigerator, the exhaust heat of the engine should be used more effectively according to the heating and cooling load and the operating condition of the generator (engine). Is desired. That is, based on the engine operating conditions and the cooling and heating capacity required for the absorption chiller, the most effective and stable engine exhaust heat can be selected to further reduce the fuel consumption required to heat the dilute solution. Therefore, it is desired to achieve high performance and low cost.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a cogeneration type absorption refrigerator and a control method thereof that realize high performance and low cost.

[0015]

The present invention adopts the following means in order to solve the above problems. According to the invention described in claim 1, a power generator using an engine as a drive source and a refrigerant gas evaporated in an evaporator are absorbed and dissolved in a high-concentration solution in the absorber, and the diluted solution discharged from the absorber is dissolved. A cogeneration system that includes an absorption refrigerator that regenerates a high-temperature high-concentration solution by heating with a burner, and returns the high-concentration solution to the absorber, and exhaust heat of the engine is also used as a heating source of the dilute solution. In the absorption refrigerator, the fuel control valve opening command value output to the fuel control valve is obtained by subtracting the cooling / heating capacity contributed by the engine exhaust heat from the fuel amount of the burner corresponding to the cooling / heating load of the absorption refrigerator. It is characterized in that a fuel amount determining means for calculating is provided.

According to the present invention, the fuel is actually supplied with respect to the energy required to satisfy the cooling and heating load, minus the energy contributed by the engine exhaust heat. Therefore, the fuel consumption amount can be suppressed.

According to a second aspect of the present invention, in the cogeneration type absorption refrigerating machine according to the first aspect, a fuel amount command value corresponding to a cooling / heating capacity contributed by the engine exhaust heat is calculated based on a load of the engine. And a rate limiter for limiting the magnitude of the fluctuation rate of the fuel amount command value calculated by the arithmetic unit.

When the fuel control valve opening command value output to the fuel control valve is suddenly changed, the cooling capacity is changed. Therefore, by limiting the change rate as in the present invention, Prevent sudden changes in the control valve opening command value.

According to a third aspect of the present invention, in the cogeneration type absorption refrigerating machine according to the first or second aspect, an operation control map showing the relationship between the engine load and the cooling / heating capacity of the engine exhaust heat which increases with the engine load. Is remembered,
The fuel amount determining means calculates a fuel amount command value corresponding to the cooling / heating capacity contributed by the engine exhaust heat, based on the engine load and the operation control map.

In the present invention, by using a predetermined operation control map, it is possible to easily determine the degree of contribution of exhaust heat of the engine and the amount of fuel to be actually supplied.

[0021] The invention according to claim 4 is based on claims 1 to 3.
In the cogeneration type absorption refrigerating machine according to, the predicted fuel amount command value is obtained based on the load change rate of the engine, and the predicted fuel amount command value is the fuel amount command value of the burner corresponding to the cooling and heating load of the absorption refrigerator. It is characterized in that a prediction command value calculating means for adding to is provided.

According to a fifth aspect of the present invention, in the cogeneration type absorption refrigerator according to the fourth aspect, the predictive command value calculating means limits the magnitude of the fluctuation rate of the predictive fuel amount command value. It is characterized by having.

According to a sixth aspect of the present invention, a power generator using an engine as a drive source and a dilute solution discharged from the absorber by absorbing and dissolving the refrigerant gas evaporated in the evaporator into a high-concentration solution in the absorber. Is regenerated as a high-temperature high-concentration solution by heating with a burner, and the high-concentration solution is returned to the absorber. An absorption refrigerator is provided, and the exhaust heat of the engine is also used as a heating source of the dilute solution. -Type absorption refrigerator, a predicted fuel amount command value is obtained based on the load change rate of the engine, and the predicted fuel amount command value is added to the burner fuel amount command value corresponding to the cooling and heating load of the absorption refrigerator. A value calculating means is provided.

According to a seventh aspect of the present invention, in the cogeneration-type absorption refrigerating machine according to the sixth aspect, the predicted command value calculating means limits the magnitude of the fluctuation rate of the predicted fuel amount command value. It is characterized by having.

When the load on the engine changes, the exhaust heat of the engine also changes, which affects the operation of the absorption refrigerator. When the fuel control valve opening command value is determined based on the chilled water outlet temperature or the like, since the response of the absorption refrigerator is slower than the load change of the engine, the cooling and heating capacity greatly varies. According to the invention of claims 4 and 6, when the load of the engine changes, the fuel control valve opening command value can be changed in advance before the absorption refrigerator responds.

Further, when the fuel control valve opening command value output to the fuel control valve is suddenly changed, the cooling capacity is changed. Therefore, the magnitude of the change rate is set as in the invention of claim 5 or 7. Is restricted to prevent a rapid change in the fuel control valve opening command value.

According to the eighth aspect of the present invention, the power generator using the engine as a drive source and the refrigerant gas evaporated in the evaporator are absorbed and dissolved in the high-concentration solution in the absorber, and the absorber is discharged. The lean solution is regenerated as a high-temperature high-concentration solution by heating it with a burner, and an absorption refrigerator for returning the high-concentration solution to the absorber is provided, and exhaust heat of the engine is also used as a heating source of the dilute solution. In the cogeneration type absorption refrigerator, the exhaust gas line from which the exhaust gas is discharged from the engine, the exhaust gas line is branched, and the exhaust gas is supplied to the heating source for the diluted solution and the atmosphere. A bypass line for discharging, and a proportional valve for controlling the opening is provided in the bypass line, and the exhaust gas supplied to the heating source of the dilute solution is controlled by controlling the proportional valve. Wherein the amount of gas is adjusted.

According to this invention, since the exhaust gas supply destination is switched between the atmosphere side and the heating source side of the dilute solution by the proportional valve, the conventionally used three-way valve becomes unnecessary. On the other hand, even if the proportional valve is fully opened, the exhaust gas slightly flows into the heating source side of the dilute solution. For this reason, the cold water temperature drops even if there is no cooling load. Therefore, even when the absorption refrigerator is stopped, the solution leaving the absorber is supplied to the heating source of the diluted solution, and the water of the refrigerant is bypassed from the evaporator to the absorber to flow into the heating source of the diluted solution. Offset the refrigeration capacity of the exhaust gas input.

According to the ninth aspect of the present invention, the power generator using the engine as a drive source and the refrigerant gas evaporated in the evaporator are absorbed and dissolved in the high-concentration solution in the absorber, and then the absorber is discharged. The lean solution is regenerated as a high-temperature high-concentration solution by heating it with a burner, and an absorption refrigerator for returning the high-concentration solution to the absorber is provided, and exhaust heat of the engine is also used as a heating source of the dilute solution. In the operation control method for a cogeneration absorption refrigerating machine, the absorption refrigerating machine is stopped, the engine is in operation, a diluted solution is supplied from the absorber, and exhaust heat is used as a heating source of the diluted solution. To bypass the refrigerant from the evaporator to the absorber.

In the present invention, the exhaust gas line from which the exhaust gas is discharged from the engine, the exhaust gas line is branched, and the exhaust gas is supplied to the exhaust gas supply line for supplying the diluted solution to the heating source and the atmosphere. In the absorption refrigeration machine provided with the bypass line, the switching can be performed by the proportional valve provided in the bypass line. That is,
Even if the proportional valve is fully opened, the exhaust gas slightly flows into the burner side. For this reason, the cold water temperature drops even if there is no cooling load. However, as in the present invention, even when the absorption refrigerator is stopped, the exhaust gas is supplied to the heating source of the dilute solution, and the refrigerant water is bypassed from the evaporator to the absorber to offset the refrigerating capacity of the exhaust gas input. As a result, it is possible to prevent the cold water temperature from decreasing, and thus a configuration without using the three-way valve becomes possible.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a cogeneration type absorption refrigerator and its operation control method according to the present invention will be described below with reference to the drawings. The overall configuration of the cogeneration type absorption refrigerator according to the present invention is shown in the system diagram of FIG. The cogeneration-type absorption refrigerator includes an absorption refrigerator ARM and a gas engine unit GE that drives a generator (not shown).

One of the gas engine parts GE is an internal combustion engine for driving a generator (not shown) according to the amount of electric power demand. In the figure, reference numeral 1 is a gas engine, 2 is a jacket water passage, and 3 is a water passage. A heat exchanger for heat radiation (so-called radiator), 4 is a three-way valve, 5 is an exhaust gas line, 6 is a silencer, and 7 is a gas engine control unit. Gas engine 1
Is operated under the control of the gas engine control unit 7 using a gas fuel such as city gas as fuel. The gas engine control unit 7 not only controls the operation / stop of the gas engine 1, but also adjusts the fuel supply amount and the like according to the load on the generator side that changes with the power demand amount, and controls the output of the gas engine 1. It has a function to do.

The jacket water flow path 2 is a flow path for circulating jacket water (engine cooling water) in order to cool the gas engine 1 and maintain it within a predetermined operating temperature range. The jacket water flow passage 2 is connected to a heat radiating heat exchanger 3 and a jacket water heat exchanger 31 on the absorption refrigerating machine ARM side which will be described later, and the flow passages can be selectively switched by the jacket water three-way valves 4 and 34, respectively. It is like this. The heat radiating heat exchanger 3 has a main purpose of cooling jacket water, while the jacket water heat exchanger 31 has a main purpose of utilizing exhaust heat of the gas engine 1. Although the heat radiating heat exchanger 3 shown in the drawing is a water-cooling type that heats the jacket water by exchanging heat with a cooling water W2, which will be described later, an air-cooling type that cools by the outside air may be used.

The exhaust gas line 5 is a conduit for releasing high-temperature exhaust gas generated by burning gas fuel, and for discharging to the atmosphere from a chimney or the like, and a silencer 6 on the way. It is provided. The exhaust gas line 5 is branched, and the exhaust gas is regenerated by the high pressure regenerator 40 on the absorption refrigerating machine ARM side described later.
It is divided into an exhaust gas supply line 5a introduced into the inside and a bypass line 5b guided to the chimney 45.

In the absorption refrigerator ARM, the evaporator 10 and the absorber 20 are formed in the same shell (high vacuum container). An evaporator tube 11 is arranged in the evaporator 10, and cold water W1 is supplied to the tube 11 via a cold water inlet line L1. The cold water W1 flowing through the evaporator tube 11 is discharged to the outside via the cold water outlet line L2. The refrigerant (water) pumped from the bottom of the evaporator 10 by the refrigerant pump P1 via the refrigerant line L11 indicated by the broken line is sprayed from the upper part of the evaporator 10 toward the evaporator tube 11. The refrigerant thus dispersed is
The latent heat of vaporization is taken from the cold water W1 flowing in the evaporator tube 11 to evaporate and vaporize to become refrigerant vapor. This refrigerant vapor passes through the gas-liquid separator 12 installed between the evaporator 10 and the absorber 20 and flows into the absorber 20 side.

The cold water W1 described above enters the evaporator 10 at a temperature of 12 ° C. (cold water inlet temperature Ti), is cooled by the evaporator tube 11, and is cooled by the evaporator 10 to, for example, 7
It is discharged at a temperature of ℃ (cold water outlet temperature To). The 7 ° C. cold water W1 supplied from the cold water outlet line L2 is used, for example, for cooling a building or for a process in a factory. The temperature of the cold water W1 that has been used for cooling in a cooling load such as a building cooling temperature rises by exchanging heat with the indoor air,
For example, the cold water inlet temperature of 12 ° C. is reached, and the evaporator 10
Flows into.

On the other hand, inside the absorber 20, the absorber tube 2
1 is arranged. Cooling water W2 is supplied to the absorber tube 21 via a cooling water line L3. Then, the concentrated solution of lithium bromide (absorption liquid) that has been pressure-fed through the solution line L21 is sprayed toward the absorber tube 21. Therefore, the sprayed concentrated lithium bromide solution absorbs the refrigerant vapor flowing into the absorber 20 side through the gas-liquid separator 12, so the concentration of the solution becomes thin.
The diluted lithium bromide solution thus diluted is collected at the bottom of the absorber 20. The heat generated in the absorber 20 is the cooling water W2 flowing in the absorber tube 21.
Is cooled by.

The diluted lithium bromide solution collected at the bottom of the absorber 20 is pumped by the solution pump P2, and the low temperature heat exchanger 30, the solution line L22, and the jacket water heat exchanger 3 are used.
It is supplied to the high-pressure regenerator 40 via the high temperature heat exchanger 32 and the solution line L23.

The high-pressure regenerator 40 has a furnace cylinder and a heat transfer tube housed in the barrel, and is equipped with a burner 41 and an exhaust gas supply line 5a as a heating source. The one burner 41 heats the dilute lithium bromide solution with heat of combustion gas or the like generated by burning the fuel gas (burner fuel) supplied through the fuel control valve 43 provided in the gas line L31. To do. The other exhaust gas supply line 5a is
High-temperature exhaust gas (exhaust heat) supplied from the exhaust gas line 5 of the gas engine section GE described above is introduced into the high-pressure regenerator 40, and the dilute solution of lithium bromide is heated in the process of passing this exhaust gas. Is. Since the exhaust gas supply line 5a is branched from the exhaust gas line 5 to the bypass line 5b by the exhaust gas three-way valve 44, introduction of the exhaust gas to the high pressure regenerator 40 can be selected as necessary. The exhaust gas flowing out from the high-pressure regenerator 40 is released from the chimney 45 into the atmosphere. The heating using the burner 41 and the heating using the exhaust gas supply line 5a using the engine exhaust heat can be used alone or in combination of both according to the operation control map of the control unit 70 described later.

The lithium bromide dilute solution supplied to the high-pressure regenerator 40 is heated by the above-mentioned heating source, so that a part of the refrigerant is evaporated and vaporized to become a high-concentration solution. This lithium bromide solution is used for the solution line L24, the high temperature heat exchanger 32,
The concentration is further increased through the low temperature heat exchanger 30 and is supplied to the absorber 20 again as a concentrated lithium bromide solution.

On the other hand, the refrigerant vapor evaporated in the high pressure regenerator 40 is supplied to the low pressure regenerator tube (not shown) of the low pressure regenerator 50, and is further supplied to the condenser 60. The low pressure regenerator 50 and the condenser 60 are configured in the same shell. In the low pressure regenerator 50, the solution line L2
The diluted lithium bromide solution branched from the solution line L22 via 5 is sprayed toward the low pressure regenerator tube.
This dilute solution of lithium bromide is heated by the low-pressure regenerator tube, and a part of the refrigerant evaporates to become a concentrated lithium bromide solution having a high concentration, and joins with the solution discharged from the high temperature heat exchanger 32 described above to obtain a low temperature. After being sent to the heat exchanger 32, it is supplied to the absorber 20 again as a concentrated lithium bromide solution.

The condenser 60 has a cooling water line L4.
A condenser tube 61 to which the cooling water W2 is supplied is arranged. In the condenser 60, the refrigerant vapor evaporated in the high pressure regenerator 40 and introduced into the low pressure regenerator 50 and the refrigerant vapor evaporated in the low pressure regenerator 50 and flowing into the condenser 60 side are condensed into the condenser. It is cooled and condensed in the tube 61 to become a refrigerant (water). The refrigerant R is sent to the evaporator 10 via the refrigerant line L14 due to gravity and pressure difference.
After being collected at the bottom of the evaporator 10, the refrigerant is sprayed again by the refrigerant pump P1 toward the evaporator tube 11 via the refrigerant line L11.

In the absorption refrigerator ARM, the evaporator 10
The heating operation is performed by causing hot water for heating to flow through the cold water system (evaporator tube 11) and introducing the high-temperature refrigerant vapor generated by the high-pressure generator 40 into the evaporator 10 through a route (not shown). You can The high-temperature refrigerant vapor introduced into the evaporator 10 is directly sprayed toward the evaporator tube 11, and the hot water flowing inside can be heated to raise the outlet temperature higher than the inlet temperature. The refrigerant (water) condensed by this heating falls to the bottom of the condenser 10 and the solution pump P2
By the operation of (3), it flows into the absorber 20 through the stabilizer solenoid valve 13 in the open state. The condensed water of the refrigerant flowing into the absorber 20 is mixed with the lithium bromide solution to form a dilute solution,
After that, it is supplied to the high pressure regenerator 40 through the solution line L22, the low temperature heat exchanger 30, the jacket water heat exchanger 31, and the high temperature heat exchanger 32.

The lithium bromide dilute solution supplied to the high pressure regenerator 40 is heated by the burner 41 and the exhaust gas supply line 5a. By supplying the high-temperature refrigerant vapor thus evaporated to the evaporator 10, the water of the refrigerant flows through the same path and repeats the state change, so that the heating operation can be continued. Even during such heating operation, the exhaust heat of the gas engine 1 can be effectively used in the jacket water heat exchanger 31 and the high temperature regenerator 40.

Now, the control unit 70 of the cogeneration type absorption refrigerator having the above-mentioned structure has an operation control map as shown in FIG. This operation control map is provided with four operation areas, and an operation area corresponding to the detected values of the cooling and heating load on the vertical axis and the engine load on the horizontal axis is selected. The first operation region is for heating the dilute solution of lithium bromide by utilizing only the exhaust heat of the gas engine 1, and is the region C in FIG.
The operating region C is the lower limit of operation of the absorption refrigerator ARM,
It is set in a region surrounded by a cooling / heating capacity line of engine exhaust heat increasing with engine load and a line of engine load 100%.

The second operation region is for heating the dilute solution of lithium bromide by using the burner heating by the burner 41 set to the lower limit of the burner load control range and the engine exhaust heat together. It is the region B. This operation region B includes an operation lower limit value of the engine load, an operation lower limit value of the absorption chiller ARM, an engine exhaust heat cooling and heating capacity line that increases with the engine load, an engine load 100% line, and a burner load control range. Is set to the area surrounded by the lower limit value of and.

The third operation region is to heat the dilute solution of lithium bromide by using the burner heating which changes within the burner load control range and the engine exhaust heat together, and is the region A in FIG. is there. This region A is set to a region surrounded by the engine load lower limit value, the engine load 100% line, the burner load control range lower limit value, and the cooling / heating load 100% line.

The fourth operation region is to heat the dilute solution of lithium bromide by using only the burner heating which changes within the burner load control range, and is regions E and F in FIG. The region E / F is set to a region surrounded by the engine load lower limit value, the absorption refrigerator ARM operating lower limit value, the engine load 0% line, and the cooling / heating load 100% line.

The lower limit of operation of the absorption chiller ARM is the minimum value of the cooling / heating load (%) that enables the operation of the absorption chiller, and is a constant value determined by various conditions. The engine load lower limit value is the minimum value of the gas engine load (%) at which the gas engine 1 can be operated, and is a constant value determined by the specifications of the gas engine used. The cooling / heating capacity line due to the exhaust heat is a value that increases as the load of the gas engine 1 increases. This cooling / heating capacity line may not only be a straight line as shown, but also a curved line depending on the characteristics of the gas engine 1. The lower limit value of the burner load control range, that is, the lower limit of the turndown of the burner 41 is the fuel control valve 4
3 is adjusted to reduce the gas fuel supply amount, and the cooling and heating load (%) obtained by the minimum heating possible by the burner 41
That is. In other words, the lower limit value of the burner load control range is the minimum cooling / heating load obtained by burning the minimum gas fuel supply amount at which the burner 41 does not misfire,
It is a constant value determined by the heating amount and various conditions of the absorption refrigerator ARM.

Next, the cooling / heating load on the vertical axis of the operation control map is obtained by calculating the ratio of the actual inlet / outlet temperature difference to the rated cold water inlet / outlet temperature difference. The case of the cooling operation will be specifically described. The cold water inlet temperature Ti of the cold water W1 supplied to the evaporator tube 11 of the evaporator 10 from the cold water inlet line L1 and the cold water outlet line L2.
It is calculated by (1) of the following [Equation 1] in the control unit 70 based on the cold water outlet temperature To discharged from and the rated cold water inlet / outlet temperature difference Ts. The cold water inlet temperature Ti used here is the detected value of the temperature sensor 14, and the cold water outlet temperature To is the detected value of the temperature sensor 15, which are input to the control unit 70, respectively.
Is a set value determined by the user. It should be noted that during heating operation, it is calculated by (2) of the following [Equation 1].

[Formula 1]

The engine load, which is the horizontal axis of the operation control map, is obtained by calculating the ratio of the power demand amount Pd to the rated power generation capacity P. More specifically, the control unit 70 uses the following [Equation 2] according to the power demand amount Pd indicating the value of the power generation amount required for the generator and the power generation capacity P during the rated operation of the gas engine 1.
Is calculated by The power demand amount Pd is determined by the gas engine control unit 7 that actually controls the gas engine 1.
Is a value input to the control unit 70 from the
It is a constant value determined in advance by the specifications of the gas engine 1 and the generator.

[Formula 2]

Therefore, the control unit 70 calculates one engine load (value on the horizontal axis) from the power demand amount Pd input from the gas engine control unit 7 and the power generation capacity P stored in advance as a constant value. In addition, the temperature sensor 14
The other cooling / heating load (value on the vertical axis) based on the cold water (hot water) inlet temperature Ti input from the cold water (hot water) outlet temperature To input from the temperature sensor 15 and the preset cold water inlet / outlet temperature difference Ts. Is calculated, and the one corresponding to the point where both calculated values intersect is selected from the first to fourth operation regions provided in the above-mentioned operation control map. In this way, when the operation area is selected and controlled from the operation control map, for example, various input data are sequentially judged based on the flowchart and compared with the control method that determines the optimum operation method, It is possible to display the operating region (driving method) that is being displayed on a panel, that is, to display it visually so that it can be shown to the administrator and the user.
The area D / below the lower limit of operation of the absorption refrigerator ARM
Since G is an inoperable region, it is not selected.

FIG. 3 is a block diagram showing main data input to the control unit 70 and main devices operated by control signals output from the control unit 70.
The electric power demand amount Pd and the operation / control signal of the gas engine 1 are input to the control unit 70 from the gas engine control unit 7. Further, the absorption refrigerating machine ARM causes the control unit 70 to
Cold water outlet temperature To, cold water inlet temperature Ti, opening of fuel control valve 43 for supplying gas fuel to burner 41 (fuel control valve opening), high pressure regenerator temperature detected by temperature sensor 46, and pressure sensor 47 detected. High-pressure regenerator pressure, engine exhaust gas temperature detected by a temperature sensor (not shown) provided at an appropriate position of the exhaust gas line 5, jacket water temperature detected by a temperature sensor (not shown) provided at an appropriate position of the jacket water flow path 2, etc. Is entered.

The intersection between the gas engine load calculated from the electric power demand Pd input from the gas engine control unit 7 to the control unit 70 and the cooling / heating load calculated from the cold water outlet temperature To and the cold water inlet temperature Ti is operation controlled. If it is in the area A of the map, the fuel control valve 4
The opening degree of 3 is controlled, and heating is performed by the burner 41 whose supply amount of burner fuel is adjusted. At the same time, the exhaust gas three-way valve 44 and the jacket water three-way valve 34 are switched to introduce the exhaust gas and the jacket water to the absorption refrigerator ARM side.
As a result, the diluted solution of lithium bromide can recover the exhaust heat from the jacket water in the jacket water heat exchanger 31, and recover the exhaust heat from the exhaust gas in the exhaust gas heat recovery heat exchanger 33 and the high temperature regenerator 40. Therefore, the exhaust heat of the gas engine 1 is used to heat the dilute solution, and an operation is performed in which heating according to the combustion amount of the gas fuel by the burner 41 in the high-pressure regenerator 40 is also used.

In this operating region A, the burner 41 is operated within the burner load control range from the lower limit of turndown, so the heating amount by the burner 41 can be adjusted according to the gas fuel supply amount. Therefore, if the cold water outlet temperature To detected by the temperature sensor 15 is lower than the set temperature, the fuel control valve 43
Is reduced to reduce the amount of heating by the burner 41 to reduce the concentration of the concentrated lithium bromide solution. On the other hand, if the cold water outlet temperature To is higher than the set temperature, the fuel control valve 43 is operated so that the opening degree is increased to increase the concentration of the concentrated lithium bromide solution by the burner 41.

Here, a method of determining the gas fuel supply amount will be described. FIG. 4 shows a fuel amount determining circuit (fuel amount determining means) 70a for determining the fuel amount, which constitutes a part of the control unit 70. In the figure, reference numeral 80 is a PI for obtaining a fuel command value from the cold water outlet temperature To.
The controller. The fuel command value obtained here is
It is a fuel command value of the burner 41 corresponding to the cooling / heating load obtained from the cold water outlet temperature To, and is a value that does not consider the contribution of the cooling / heating capacity by the exhaust gas of the gas engine 1. Reference numeral Fx is a function (calculator) that calculates a fuel command value corresponding to the refrigerating capacity of the exhaust gas of the gas engine 1 based on the gas engine load. Reference numeral 83 is PI
It is a subtracter that subtracts the calculation result of the function Fx from the fuel command value of the controller 80 and outputs it as the fuel control valve opening degree to the fuel control valve 43. More specifically describing the function Fx, in the operation control map of FIG. 2, when the gas engine load is X1 and the cooling and heating load is Y1, the contribution of exhaust heat of the gas engine is the amount indicated by the symbol a. is there. The function Fx calculates a command for the amount of fuel of the refrigerating capacity corresponding to this code a. Therefore, the fuel control valve opening degree calculated by the subtractor 83 has a value corresponding to the refrigerating capacity shown by the symbol b in FIG.

As described above, the fuel control valve opening actually output to the fuel control valve 43 is the amount of energy required to satisfy the cooling and heating load minus the contribution of engine exhaust heat. Therefore, the amount of fuel consumption can be suppressed.

By the way, as described above, in FIG. 4, the actual fuel control valve opening is obtained by subtracting the command value for the fuel amount due to the exhaust heat of the gas engine 1 from the fuel command value by the PI controller 80. However, when the engine load changes rapidly, the fuel control valve opening also changes rapidly with the engine load. Although the response of the absorption chiller is delayed due to the engine load change, if the fuel control unit opening is drastically changed, the cooling / heating capacity will drastically change. Therefore, as in the fuel amount determination circuit 70b of FIG. 5, the output of the function Fx is passed through the rate limiter 85, so that the fuel amount command value corresponding to the cooling / heating capacity contributed by the exhaust gas is changed by a predetermined amount. Do not change more than the rate. For example, as shown in FIG. 6, even when the engine load sharply decreases as indicated by reference sign a, the fluctuation becomes gentle as indicated by reference sign b due to the action of the rate limiter 85. Similarly, even when the engine load suddenly increases, the fluctuation of the fuel control valve opening degree can be moderately suppressed. As a result, it is possible to suppress a sudden change in the cooling and heating capacity and to realize stable operation.

Next, a modification of the above embodiment will be described. What is shown in FIG. 7 is a prediction command value calculation circuit (prediction command value calculation means) 70c for determining the fuel amount,
It constitutes a part of the control unit 70. In the figure, reference numeral 9
0 is a differentiation circuit that differentiates the engine load value, and Fx
1, Fx2 is a predetermined function, 91 is a function Fx1 and a function Fx
2, 85 'is a rate limiter for suppressing a change above a predetermined fluctuation rate. Now
For example, when the engine load sharply decreases as indicated by the symbol a in FIG. 8A, the value based on the variation rate (differentiation) of the engine load is obtained by passing through the differentiator 90 and the function Fx1. Further, the function Fx2 and the integrator 91 convert it into a fuel command value that reflects the magnitude of the engine load. This fuel command value is shown by the symbol b in FIG. However, since a rapid change in the fuel control valve opening causes a change in the cooling capacity, the rate limiter 85 ′ gently changes it as indicated by the symbol c, and this is used as the predicted fuel amount command value in the adder 8
6 is added to the fuel amount command value based on the cold water outlet temperature To. As a result, a signal is given to the refrigerator for a relatively long time, and it is possible to further suppress the influence of the engine load fluctuation on the refrigerator. Although the case where the gas engine load is suddenly reduced has been shown above, it is needless to say that the present invention is also applied to the case where the gas engine load is rapidly increased.

With this configuration, it is possible to suppress the influence of the absorption refrigerator when the engine load fluctuates rapidly. That is, the thermal energy of the exhaust gas changes abruptly due to the rapid change of the engine load. On the other hand,
There is a delay in the response of the absorption refrigerator due to the detection of the variation of the cold water outlet temperature To and the adjustment of the fuel control valve opening based on the variation. Therefore, if you do not consider the engine load fluctuation,
There is a possibility that the control of the absorption refrigerator will not be in time for changes in the thermal energy of the exhaust gas, and the amount of fuel will temporarily become excessive or excessive. With the configuration of this example, when the load of the engine changes, the fuel control valve opening command value can be changed in advance before the absorption refrigerator responds.

Furthermore, as shown in FIG. 9, FIG.
Of course, the fuel amount determination circuits 70a and 70b shown in FIG. 7 and the predicted command value calculation circuit 70c shown in FIG. 7 may be combined. With this configuration, it is possible to calculate the fuel control valve opening degree by subtracting the fuel amount corresponding to the refrigerating capacity of the exhaust gas of the gas engine according to the load of the engine 1, and the load of the gas engine It is possible to realize operation that suppresses the influence of fluctuations.

Next, another embodiment of the present invention will be described. The same components as those in the above embodiment are designated by the same reference numerals, and the description thereof will be omitted. FIG. 10 is a system diagram showing the overall configuration of a cogeneration type absorption refrigerator. In this example, in comparison with the cogeneration type absorption refrigerator of FIG.
A proportional valve 95 for controlling the opening of the bypass line 5b is installed, while the exhaust gas line 5 to the bypass line 5
The exhaust gas three-way valve 44 is removed at the branch portion branching to b and the exhaust gas supply line 5a. Other configurations and controls are the same as those of the absorption refrigerator shown in FIG.

Now, in the operation control map of FIG. 2, when the engine is in a low load state such as the regions B and C, the gas engine 1
The state of the absorption refrigerating machine is likely to fluctuate depending on whether the heat energy of the exhaust gas is excessive or when the burner 41 is ignited because the heat of the exhaust gas is not sufficient. However, if the exhaust gas three-way valve 44 sends exhaust gas to the high-pressure regenerator 40 as in the above-described embodiment, it is difficult to control the thermal energy by the exhaust gas, and if it is excessive, the stabilizer solenoid valve 13 is used. It was necessary to open the valve to suppress the capacity of the absorption refrigerator, and to frequently turn on / off the burner 41 in order to stabilize the state of the absorption refrigerator. Therefore, there is a problem that stable control is difficult. In the present embodiment, by controlling the opening degree of the proportional valve 95, the excess input exhaust gas is bypassed to the bypass line 5b and escaped, and the refrigerating machine capacity is adjusted by not introducing it into the high pressure regenerator 40. Therefore, the absorption refrigerator can be kept more stable in the low load region, and the number of times the burner 41 is turned on / off can be reduced. Therefore, the life of the burner can be extended.

On the other hand, in this example, when the absorption refrigerator is stopped and the gas engine is operating, even if the proportional valve 95 is fully opened, the exhaust gas slightly flows into the high pressure regenerator 40. For this reason, the cold water temperature drops even if there is no cooling load. Therefore, in this example, even when the absorption refrigerator is stopped, the solution pump P2 is driven to circulate the solution and the stabilizer solenoid valve 13 is opened,
Water of the refrigerant is supplied from the evaporator 10 to the absorber 20 to offset the refrigerating capacity of the exhaust gas input. As described above, in the present embodiment, by using the proportional valve 95, an expensive three-way valve can be omitted, so that a significant cost reduction can be realized.

The configuration of the present invention is not limited to the above-described embodiments, but may be modified as appropriate without departing from the scope of the present invention. For example, a drive source for a generator other than a gas engine. No internal combustion engine is used, or the burner fuel is not limited to gas.

[0066]

According to the cogeneration type absorption refrigerator and the operation control method thereof of the present invention described above, the following effects can be obtained. According to the invention described in claim 1, the fuel is actually supplied with respect to the energy required to satisfy the cooling and heating load, minus the contribution of the engine exhaust heat. Therefore, fuel consumption can be suppressed, and a highly efficient cogeneration type absorption refrigerator can be realized. According to the second aspect of the present invention, by limiting the fluctuation rate of the fuel control valve opening command value output to the fuel control valve, it is possible to prevent a rapid fluctuation of the fuel control valve opening command value. it can. Therefore, more stable operation can be realized. According to the third aspect of the present invention, by using the predetermined operation control map, it is possible to easily determine the degree of contribution of the exhaust heat of the engine and the amount of fuel to be actually supplied.

According to the fourth and sixth aspects of the present invention, when the load of the engine changes, the fuel control valve opening command value can be changed in advance before the absorption refrigerator responds.
Therefore, stable operation can be realized. Further, by limiting the magnitude of the fluctuation rate as in the invention of claim 5 or 7, it is possible to prevent a rapid fluctuation of the fuel control valve opening command value and realize more stable operation.

According to the eighth aspect of the present invention, since the exhaust gas supply destination is switched between the atmosphere side and the burner side by the proportional valve, the conventionally used three-way valve becomes unnecessary, and the cost is greatly reduced. Down can be realized. According to the invention as set forth in claim 9, even if the three-way valve is not used, the refrigerating capacity of the exhaust gas can be canceled when the absorption refrigerator is stopped.

[Brief description of drawings]

FIG. 1 is a system diagram of an overall configuration showing an embodiment of a cogeneration-type absorption refrigerator according to the present invention.

FIG. 2 is a diagram showing an operation control map formed in the control unit of FIG.

FIG. 3 is a block diagram of a control unit shown in FIG.

FIG. 4 is a diagram showing a configuration of a fuel amount determination circuit that constitutes a part of a control unit.

FIG. 5 is a diagram showing the configuration of another example of the fuel amount determination circuit that constitutes a part of the control unit.

6 is a diagram showing the operation of the rate limiter according to FIG.

FIG. 7 is a diagram showing a configuration of a prediction command value calculation circuit forming a part of a control unit.

FIG. 8 is a diagram illustrating an operation of a prediction command value calculation circuit.

FIG. 9 is a diagram showing an example in which a fuel amount determination circuit and a predicted command value calculation circuit are combined.

FIG. 10 is a system diagram of an overall configuration showing another embodiment of a cogeneration type absorption refrigerator.

[Explanation of symbols]

1 gas engine 5 Exhaust gas line 7 Gas engine control unit 10 evaporator 13 Stabilizer valve 20 absorber 30 low temperature heat exchanger 31 jacket water heat exchanger 32 High temperature heat exchanger 34 jacket water three-way valve 40 high-pressure regenerator 41 burners 43 Fuel control valve 44 Exhaust gas three-way valve 50 low pressure regenerator 60 condenser 70 Control unit 70a Fuel amount determination circuit (fuel amount determination means) 70b Fuel amount determination circuit (fuel amount determination means) 70c Prediction command value calculating circuit (prediction command value calculating means)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F25B 15/00 306 F25B 15/00 306C 306V (72) Inventor Minoru Matsuo 2-chome Niihama, Arai-cho, Hyogo Prefecture No. 1 Mitsubishi Heavy Industries, Ltd. Takasago Research Institute (72) Inventor Shuichi Matsushita 3-1, Asahi-cho, Nishibiwajima-cho, Nishikasugai-gun, Aichi Prefecture F-Term (Reference) 3L093 BB05 BB22 BB26 BB37 CC00 DD08 EE00 GG00 HH08 HH11 HH12 JJ02 JJ04 KK05 LL03

Claims (9)

[Claims] 1. A power generator using an engine as a drive source, and a refrigerant gas evaporated in an evaporator is absorbed and dissolved in a high-concentration solution in an absorber, and a dilute solution discharged from the absorber is heated by a burner. An absorption refrigerator is provided, which is regenerated as a high-temperature high-concentration solution and returns the high-concentration solution to the absorber.
In a cogeneration type absorption refrigerator that also uses the exhaust heat of the engine as a heating source of the diluted solution, subtract the cooling / heating capacity contributed by the engine exhaust heat from the fuel amount of the burner corresponding to the cooling / heating load of the absorption refrigerator. According to the above, the cogeneration type absorption refrigerator is provided with a fuel amount determining means for calculating a fuel control valve opening command value output to the fuel control valve. 2. The cogeneration-type absorption refrigerating machine according to claim 1, wherein an arithmetic unit for calculating a fuel amount command value corresponding to a cooling / heating capacity contributed by the engine exhaust heat based on a load of the engine; A cogeneration type absorption refrigerating machine, which is provided with a rate limiter for limiting the magnitude of the fluctuation rate of the fuel amount command value calculated by the container. 3. The cogeneration absorption refrigerating machine according to claim 1, wherein an operation control map showing a relationship between an engine load and an engine exhaust heat cooling / heating capacity that increases with the engine load is stored, and the fuel amount is stored. The cogeneration-type absorption refrigerating machine, wherein the determining means calculates a fuel amount command value corresponding to the cooling / heating capacity contributed by the engine exhaust heat, based on the engine load and the operation control map. 4. The cogeneration type absorption refrigerating machine according to claim 1, wherein a predicted fuel amount command value is obtained based on a load change rate of the engine, and the predicted fuel amount command value is used as a cooling / heating load of the absorption refrigerating machine. A cogeneration-type absorption refrigerating machine is provided with a predicted command value calculation means for adding to the fuel amount command value of the burner corresponding to the above. 5. The cogeneration absorption refrigerator according to claim 4, wherein the predicted command value calculation means includes a rate limiter for limiting the magnitude of the fluctuation rate of the predicted fuel amount command value. A cogeneration type absorption refrigerator. 6. A power generator using an engine as a drive source, and a refrigerant gas evaporated in an evaporator is absorbed and dissolved in a high-concentration solution in the absorber, and the diluted solution discharged from the absorber is heated by a burner. A cogeneration-type absorption refrigerating machine comprising an absorption refrigerating machine which is regenerated as a high-temperature high-concentration solution and which returns the high-concentration solution to the absorber, and exhaust heat of the engine is also used as a heating source of the diluted solution. A predicted fuel amount command value is obtained based on the load change rate, and the predicted fuel amount command value is added to the predicted fuel amount command value of the burner corresponding to the cooling and heating load of the absorption refrigerator. A cogeneration type absorption chiller that is characterized by 7. The cogeneration type absorption refrigerator according to claim 6, wherein the predicted command value calculation means includes a rate limiter that limits the magnitude of the fluctuation rate of the predicted fuel amount command value. A cogeneration type absorption refrigerator. 8. A power generator using an engine as a drive source, and a refrigerant gas evaporated in an evaporator is absorbed and dissolved in a high-concentration solution in an absorber, and the diluted solution discharged from the absorber is heated by a burner. Regeneration as a high-temperature high-concentration solution, comprising an absorption refrigerator that returns this high-concentration solution to the absorber, in the cogeneration-type absorption refrigerator that also uses exhaust heat of the engine as a heating source of the dilute solution, An exhaust gas line from which the exhaust gas is discharged from the engine; an exhaust gas line that branches, an exhaust gas supply line that supplies the exhaust gas to a heating source of the diluted solution, and a bypass line that discharges the exhaust gas to the atmosphere; A proportional valve for controlling the opening is installed in the bypass line, and by controlling the proportional valve, the amount of exhaust gas supplied to the heating source of the dilute solution can be adjusted. Cogeneration type absorption refrigerating machine according to symptoms. 9. A power generator using an engine as a driving source, and a refrigerant gas evaporated in an evaporator is absorbed and dissolved in a high-concentration solution in the absorber, and the diluted solution discharged from the absorber is heated by a burner. An absorption refrigerator is provided, which is regenerated as a high-temperature high-concentration solution and returns the high-concentration solution to the absorber.
In the operation control method of a cogeneration type absorption refrigerating machine in which exhaust heat of the engine is also used as a heating source of the dilute solution, the absorption refrigerating machine is stopped, the engine is in operation, and the dilute solution from the absorber is used. Is supplied and exhaust heat is supplied as a heating source for the dilute solution, and the refrigerant is bypassed from the evaporator to the absorber.