JP4283633B2 - Double-effect absorption chiller / heater with exhaust heat recovery unit - Google Patents

Description

  The present invention relates to a double-effect absorption chiller / heater having an exhaust heat recovery device, specifically an absorber, a low-temperature regenerator, a high-temperature regenerator, an evaporator, a condenser, a solution (absorbing liquid) heat exchanger, and the like. The double-effect absorption chiller / heater has a waste heat recovery device that recovers waste heat from outside, reducing the amount of high-grade heating combustion energy (city gas, LPG, kerosene, heavy oil, etc.) used. , Concerning a double-effect absorption chiller / heater with a waste heat recovery device that incorporates a recovery device that recovers external waste heat that effectively uses exhaust heat supplied from the outside to improve efficiency It is.

  2. Description of the Related Art Conventionally, a double-effect absorption chiller / heater as illustrated in FIG. 5 is known (FIG. 5 shows an example in which cold water is obtained). This absorption chiller / heater constitutes a reverse cycle in which an absorbing liquid (for example, an aqueous solution of lithium bromide) flows from the absorber a to the high temperature regenerator e through the low temperature regenerator c. The absorption cycle in this absorption chiller / heater will be described. First, an absorption liquid (a rare absorption liquid) whose concentration has been reduced by absorbing a large amount of refrigerant vapor in the absorber a is transferred from the absorber a to the low-temperature heat exchanger b. After being fed and heated by the low-temperature heat exchanger b, it is fed to the low-temperature regenerator c. The rare absorbent is regenerated at a low temperature in the low temperature regenerator c, and a part of the absorbed refrigerant is released, and the concentration is increased by that amount to become an intermediate concentration absorbent (intermediate absorbent). Next, the intermediate absorbent is fed from the low temperature regenerator c to the high temperature heat exchanger d, heated by the high temperature heat exchanger d, and then fed to the high temperature regenerator e.

  The intermediate absorption liquid is regenerated at a high temperature in the high temperature regenerator e, and a part of the absorbed refrigerant (for example, water vapor) is released to further increase the concentration to become a high concentration absorption liquid (concentrated absorption liquid). . The concentrated absorbent is returned to the heating side of the high temperature heat exchanger d as a heating source for heating the intermediate absorbent, and further the heating source for heating the rare absorbent on the heating side of the low temperature heat exchanger b. Is returned to the absorber a. The returned concentrated absorbing liquid is sprayed on the heat transfer tube in the absorber a and absorbs the refrigerant vapor again while being cooled by the cooling water to become the rare absorbing liquid.

In such a double-effect absorption chiller / heater, high-temperature steam (steam) is supplied to the high-temperature regenerator e from a steam boiler f as a heating source, and intermediate absorption is performed by this steam. The absorbed refrigerant is released by heating the liquid, and the released refrigerant vapor is used by the low temperature regenerator c as a heating source in the low temperature regenerator c, and then returned to the condenser g for condensation. To do. The refrigerant liquid (for example, water) from the condenser g enters the evaporator h, and the condensed refrigerant liquid is sprayed on the heat transfer pipe (water is circulating) of the evaporator h by a refrigerant pump and cooled by latent heat of evaporation. Cold water is obtained.
In addition, a bypass pipe k is provided to connect the absorption liquid pipe i from the low temperature regenerator c and the heating side absorption liquid pipe j between the high temperature heat exchanger d and the low temperature heat exchanger b. A part of the intermediate concentrated absorbent that exits c and is supplied to the high-temperature regenerator e is bypassed to the concentrated absorbent pipe that returns to the absorber a.
Instead of providing the steam boiler f, a high temperature regenerator e is provided with a combustion device, and the absorption liquid in the high temperature regenerator is heated and concentrated by heating the high temperature combustion exhaust gas from the combustion device. Heavy-effect absorption cold / hot water machines are also well known.

  Conventionally, double-effect absorption chiller water heaters, absorption chiller water heaters that use external waste heat, etc. are already known, but due to a decrease in exhaust heat hot water temperature after heat recovery of external waste heat, other An absorption chiller / heater that takes into account the impact on the equipment (return side of the waste water) has not been developed.

When the use amount of the combustion energy for heating is low and the cooling load is low, the temperature level during the operation cycle of the absorption chiller / heater becomes low. At this time, if external exhaust heat is supplied and used as a heat source for an absorption operation cycle, the temperature of the operation cycle is low, so that the heat recovery amount of the external exhaust heat is increased, and a favorable effect is obtained from the viewpoint of effective use of heat. At this time, the outlet temperature of the exhaust heat hot water (exhaust hot water) decreases corresponding to the temperature decrease of the operation cycle, and the heat recovery amount increases.
However, an increase in the amount of heat recovery is preferable from the viewpoint of effective use of heat, but a decrease in the temperature of the return exhaust heat hot water may adversely affect other devices. In particular, when the external heat source system device is a gas engine and the heat of the jacket cooling water of the gas engine is used as an exhaust heat source, the efficiency of the gas engine is reduced.

On the other hand, when the cooling load is extremely reduced and it is no longer necessary to recover the exhaust heat, the exhaust water recovery heat exchanger is bypassed to return the hot water to the jacket side of the gas engine. The gas engine is not sufficiently cooled, and problems such as a reduction in efficiency and overheating occur.
For this reason, in exhaust heat utilization systems and devices combined with gas engines, the temperature of the hot water returned to the gas engine is also controlled at the same time as the control device for controlling the temperature and flow rate on the inlet side of the heat recovery heat exchanger that recovers exhaust heat. A control device that adjusts and controls the exhaust heat recovery amount by performing some control is required, and a complicated control device that controls the exhaust heat hot water temperature at the entrance and exit of the exhaust heat recovery heat exchanger is required.
The air conditioning load in the absorption chiller / heater, the power generation load of external heat source system equipment such as a gas engine, the exhaust heat / hot water temperature in the chiller / heater, and the fuel reduction rate in the chiller / heater can be summarized roughly. As shown in Table 1.

  As shown in Table 1, when the balance between the cooling load and the power generation load is changed, the operating conditions are changed, and in particular, the temperature condition of the absorbing liquid circulating inside the absorption chiller / heater side is changed. Therefore, it can be seen that it is difficult to perform efficient heat recovery and energy-saving operation of the absorption chiller / heater by controlling only a part of the temperature conditions.

  Conventionally, as a double-effect absorption chiller / heater, the control is performed by detecting the chilled water outlet temperature or the chilled water inlet temperature to control the heating amount, and the inlet temperature when the exhaust hot water enters the exhaust heat recovery device. A control system has been invented for controlling the heat recovery amount of the absorption chiller / heater by controlling the temperature (for example, see Patent Document 1 and Patent Document 2). However, in addition to load control and exhaust heat recovery control of the absorption chiller / heater, a control circuit (method) that considers the effect on the equipment side (for example, gas engine) that detects the return temperature and generates exhaust heat Has not been proposed.

In addition, as a double-effect absorption chiller / heater, an absorber, a low-temperature regenerator, a high-temperature regenerator, a condenser, an evaporator, an absorption liquid that is returned to the absorber is introduced as a heat source, and is absorbed from the absorber. Low-temperature heat exchanger that preheats liquid, high-temperature heat exchanger that preliminarily absorbs the absorption liquid that is introduced from the high-temperature regenerator as a heat source and that is directed to the high-temperature regenerator, externally generated hot water and absorber introduced from outside the system In an absorption chiller / heater equipped with a hot water heat exchanger for exchanging heat with all or part of the absorption liquid derived from the low temperature heat exchanger, the absorption liquid derived from the absorber is converted into the low temperature heat exchanger. The bypass line that bypasses the low-temperature heat exchanger is provided in the pipe line that goes to the hot water heat exchanger via the heat exchanger, and the pipe that returns the absorbent to the absorber via the low-temperature heat exchanger is connected to the evaporator. Known to have a configuration with a tension line connected. Is (e.g., see Patent Document 3).
Japanese Patent Laid-Open No. 11-83228 (2nd page, FIG. 2) JP 2000-65436 A (second page, FIG. 1) JP 2003-207222 A (2nd page, 3rd page, FIG. 1)

  The problem to be solved is that it has a large effect on the external heat source equipment (for example, gas engine in the cogeneration system) due to the decrease in the exhaust heat hot water temperature after recovering the external exhaust heat. The efficiency of the external heat source device is reduced. The object of the present invention is a double-effect absorption chiller / heater that is more efficient than conventional double-effect absorption chiller / heaters, and that can save energy. Exhaust heat recovery with a control system that can maximize the use of exhaust heat and reduce the impact on external heat source equipment in a dual effect machine that reduces the amount of gas in a high-temperature regenerator It is to obtain a double-effect absorption chiller / heater having a vessel.

In the control of an absorption chiller / heater that recovers heat using external waste heat, normally, the control of the amount of exhaust heat supplied from the outside by detecting the chilled / hot water outlet temperature of the absorption chiller / heater, and the chiller / heater Control of the amount of combustion of the own combustion equipment. In other words, when the cooling load is high, all exhaust heat is recovered, and the amount of combustion is increased and decreased to control the chilled water outlet temperature to be constant. Shut off the fuel supply to the plant and perform air conditioning operation using only the exhaust heat as the heat source.
From the standpoint of the absorption chiller / heater unit, there is no problem with the control corresponding to the increase / decrease of the normal cooling / heating load. However, the load on the facility side that generates waste heat and supplies this waste heat to the absorption chiller / heater, that is, the impact of the waste heat source such as a gas engine that is operating in combination with the generator, is not considered at the same time. However, it cannot be said to be optimal control, and driving tends to be unstable.
However, in consideration of these points, a double-effect absorption chiller / heater and a control device therefor have not been proposed which further improve efficiency and save energy.

  The present invention is a dual-effect absorption chiller / heater incorporating an external exhaust heat recovery device, which effectively recovers external exhaust heat, and other heat source equipment (cogeneration system) due to a decrease in the temperature of returned exhaust heat hot water. In this example, in order to reduce the impact on gas engines, etc., in addition to the conventionally known heat recovery methods, control and recovery efficiency during exhaust heat recovery are improved, Install a waste heat recovery device that takes into account the efficiency of the return side equipment (equipment such as a gas engine that is also a heat source device that generates waste hot water), and consider the effect on the heat source equipment on the waste heat supply side, and The most important feature is that peak cut control of the exhaust heat recovery amount and refrigerant temperature control are performed so as to increase the efficiency of the double effect machine.

  The double-effect absorption chiller / heater having the exhaust heat recovery device of the present invention includes an absorber, a low-temperature regenerator, a high-temperature regenerator, an evaporator, a condenser, an absorption liquid heat exchanger, an absorption liquid pump, a refrigerant pump, etc. The pipes are connected to form an absorption liquid flow path, a refrigerant flow path, and a refrigerant vapor flow path so that the absorption liquid of the absorber is guided to the low temperature regenerator, and then the absorption liquid of the low temperature regenerator is guided to the high temperature regenerator. In reverse flow type dual-effect absorption chiller / heater, the exhaust heat from the outside is recovered and used as a heating source, and the absorption liquid is heated and evaporated to absorb the refrigerant absorbed in the absorption liquid. An exhaust heat recovery unit is installed in front of the low-temperature regenerator to increase the concentration of the liquid, and the amount of heating heat that raises the concentration of the absorption liquid by heating the absorption liquid with the low-temperature regenerator is controlled by the amount of exhaust heat recovered from the outside. Reducing the amount of heat exchange in the low-temperature regenerator. Even if the amount of refrigerant vapor generated as a heating source of the low-temperature regenerator is reduced by heating and concentrating the absorption liquid generated by the regenerator, the exhaust heat recovery operation can be performed according to changes in the heating and cooling load, and the high-temperature regenerator It is characterized by reducing the consumption of high-grade heating fuel used for heating and saving energy.

In this double-effect absorption chiller / heater, the ratio of heating heat that heats the absorbent with a low-temperature regenerator and raises the concentration of the absorbent is controlled by controlling the amount of exhaust heat recovered from the outside, and the heating / cooling load is 100-0. %, It is configured to reduce by 15 to 100%.
In addition, compared to the double-effect absorption chiller / heater without a waste heat recovery device, the consumption of high-grade heating fuel used for heating in a high-temperature regenerator is rated by providing a waste heat recovery device. Energy saving is achieved by reducing 15-30% during load operation and 15-100% during low load (partial load) operation. In addition, an exhaust hot water control valve, an exhaust hot water pipe, and an exhaust hot water controller for recovering external exhaust heat and using it as a heat source for the exhaust heat recovery device are provided.

In addition, when the temperature of the exhaust water at the inlet of the exhaust heat recovery device is higher than the temperature of the absorption liquid heated in the exhaust heat recovery device by a predetermined temperature (for example, plus 3 ° C), the exhaust heat water is recovered by controlling the exhaust water control valve. It is configured to flow into the vessel and heat the absorption liquid.
Further, the temperature of the exhaust water is returned so that it does not adversely affect the operating conditions and efficiency of the heat source system equipment (for example, a gas engine) that is a heat source for generating external exhaust heat (for example, 60 ° C. or more). The exhaust warm water temperature is controlled using the three-way valve opening upper limit peak cut control, and the exhaust warm water flows into the exhaust heat recovery device by a predetermined amount to heat the absorption liquid. Further, a three-way valve for controlling the flow rate of the exhaust heat hot water is provided at the exhaust heat recovery device inlet, and the upper limit peak cut control of the three-way valve is a proportional control type.

In addition, when the flow rate control of the exhaust heat water entering the exhaust heat recovery unit is performed and the peak cut control of the exhaust heat water is performed, and the heating amount is insufficient for the demand of the air conditioning load, the combustion amount is increased and controlled. It is configured. Further, when the amount of heating is smaller than the load by the load control calculation, control is performed to increase the combustion control amount and correct the shortage of the exhaust hot water amount. Further, when there is no heating due to external exhaust heat, a selection specification is provided so that the operation mode can be switched so that the operation is started from the combustion control operation at the time of startup.
The absorption pump outlet of the absorber and the evaporator are connected via an absorption liquid distribution pipe having a flow control valve, and the temperature sensor provided in the cold water outlet pipe or the cold water inlet pipe of the evaporator and the flow control valve are connected. Via the control device (control panel), the amount of absorbed liquid injected into the evaporator can be controlled by the temperature detected by the cold water temperature sensor, and the refrigerant accumulated in the evaporator refrigerant pool and the absorbed liquid flowing in are evaporated. An overflow weir or overflow pipe provided in the vessel is configured to flow down or return to the absorber liquid reservoir.

Furthermore, the refrigerant temperature sprayed by the evaporator, the refrigerant temperature in the evaporator refrigerant pool and the cold water outlet temperature are monitored, and either the refrigerant temperature before the absorption liquid injection and the refrigerant temperature after the absorption liquid injection or the cold water outlet temperature or Both the temperature differences are compared, and the injection amount is controlled by the absorption liquid flow rate control valve so that the temperature difference (Δt ° C.) does not exceed the set value.
In addition, when exhaust heat is supplied to the exhaust heat recovery unit and exhaust heat is recovered, the exhaust heat is exhausted during partial load operation that does not require reheating combustion operation with the combustion device of the high temperature regenerator. In order to increase the recovery amount as much as possible, the operation of the absorption pump is controlled at the rated operation to increase the circulation rate of the absorption liquid, and if the load increases and the reheating combustion operation becomes necessary, the operation depends on the load. The discharge amount of the absorption liquid pump is controlled so that the absorption liquid circulation amount operates efficiently.
Also, during the partial load operation in which the exhaust heat is passed through the exhaust heat recovery device and the exhaust heat is recovered to reduce the heat of combustion and the combustion device of the high temperature regenerator is used for the partial load operation, the high temperature regeneration is performed due to load fluctuations, etc. In order to prevent the liquid level in the chamber from fluctuating and causing a safety stop due to empty can operation or low liquid level, the discharge rate of the absorption pump is controlled to ensure the amount of absorption liquid circulating to the high temperature regenerator, It is configured so that stable operation can be continuously performed.

The exhaust heat recovery unit is configured to be a pool boiling type shell-and-tube heat exchanger in which exhaust hot water that is a heating fluid flows inside the tube and a rare absorbing liquid flows outside the tube.
In this case, the rare absorption liquid outlet of the pool boiling type shell-and-tube heat exchanger is provided near the uppermost stage of the heat transfer tube group constituting the shell-and-tube heat exchanger, The arrangement of the heat transfer tubes at the uppermost stage and the lower stage of the heat transfer pipe group does not hinder the outflow of the surfactant added to the absorbent from the rare absorbent outlet.
In addition, the arrangement of the heat transfer tubes in the uppermost stage and the lower stage of the exhaust heat recovery unit is a grid arrangement. Further, the refrigerant vapor line from the exhaust heat recovery unit to the low-temperature regenerator is provided with a branch line connected to the heating side of the evaporator, and provided with cooling / heating switching means for switching between cooling and heating for the branch line, The cooling / heating switching means is switched to heating, and the refrigerant vapor from the exhaust heat recovery device is guided to the evaporator to heat the hot water flowing in the heat transfer pipe in the evaporator.

As described above, in the dual-effect absorption chiller / heater that effectively recovers exhaust heat supplied from the outside to save energy, the external exhaust heat is effectively recovered and exhaust heat is generated. In addition to the conventional load control that detects the chilled water outlet (inlet) temperature of the absorption chiller / heater to control the heating amount in order to eliminate the influence on the equipment side, external exhaust heat is reduced. In order to recover as much as possible and eliminate the influence on the equipment that generates exhaust heat, the return temperature of the exhaust heat depends on the change (high or low) of the absorption liquid temperature circulating through the chiller / heater by changing the external load Exhaust heat recovery amount control that performs peak cut control that is controlled while changing, and controls so that the effect of recovering more exhaust heat recovery amount and hunting of the control operation of the exhaust heat recovery control device can be prevented to enable stable operation Under the circuit and cold water outlet (inlet) temperature Ri only to prevent, providing the absorption liquid pipe connected so as to inject the absorbing liquid to the evaporator (coolant reservoir), the absorption liquid control valve equipped in the middle thereof piping.
At this time, as shown in FIG. 2, the temperature of the refrigerant sprayed by the evaporator or the cold water outlet temperature is monitored, and the refrigerant temperature before the absorption liquid injection, the refrigerant temperature after the absorption liquid injection or the cold water outlet temperature, or both And the mixing amount is controlled by the absorbing liquid control valve so that the temperature difference (Δt ° C.) does not exceed the set value. The absorption liquid to be injected is guided by a pipe branched from the discharge port of the low temperature absorption liquid pump.

The present invention has the following effects.
(1) In the dual effect absorption chiller / heater, by performing peak cut control and refrigerant temperature control of the exhaust heat recovery amount in the exhaust heat recovery device, the exhaust heat recovery amount can be increased and the efficiency can be increased.
(2) Decreasing the temperature of the chilled water outlet (inlet) by mixing a part of the absorption liquid from the absorber into the refrigerant in the refrigerant pool and spilling (returning) the refrigerant and the absorption liquid into the absorption liquid reservoir of the absorber. If the temperature is too high, the operation of the safety device can be prevented, and the return temperature of the exhaust water can be stabilized by continuously flowing the exhaust water, thereby reducing the adverse effect on the external heat source equipment such as the gas engine.
(3) Absorption liquid that exchanges heat with waste water does not drop too much due to the heat of waste water, rises quickly when the load increases during operation, and reduces the amount of fuel that burns up. Therefore, it is possible to increase the energy saving effect by effectively using the exhaust heat.

  In a dual-effect absorption chiller / heater equipped with an exhaust heat recovery unit, it is configured to perform peak cut control of exhaust heat recovery amount and refrigerant temperature control for the purpose of maximizing exhaust heat and increasing efficiency. It was realized.

Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications.
FIG. 1 shows an absorption chiller / heater according to a first embodiment of the present invention. In this embodiment, the absorber 10, the low-temperature absorption liquid pump 12, the low-temperature heat exchanger 14, the low-temperature regenerator 16, the high-temperature absorption liquid pump 18, the high-temperature heat exchanger 20, the high-temperature regenerator 22, the condenser 24, and the evaporator 26. In the reverse cycle double-effect absorption refrigerator having the refrigerant pump 28 and the absorption liquid pipe connecting these devices, the refrigerant pipe and the like as components, the upstream side of the low-temperature regenerator 16 in the absorption liquid flow path Further, an exhaust heat regenerator 30 described later is provided. In FIG. 1, an arrow attached to the solid line indicates the flow direction of the absorbing liquid, the refrigerant liquid, or water, and an arrow attached to the broken line indicates the flow direction of the refrigerant vapor or the mixture of the refrigerant vapor and the condensed refrigerant (refrigerant drain). Indicates.

  32 is a bypass pipe for bypassing a part of the absorbent from the low temperature regenerator 16 to the return concentrated absorbent pipe from the high temperature heat exchanger 20. Reference numeral 34 denotes a cold / hot water pump, 36 denotes a cooling water pump, and 38 denotes a first cooling / heating switching valve. Further, the outlet pipe of the low-temperature absorption liquid pump 12 branches, and one branch absorption liquid pipe 40 is connected to the refrigerant liquid reservoir 42 of the evaporator 26. The branch absorption liquid pipe 40 is provided with an absorption liquid flow rate adjustment valve 44, which is connected to an absorption chiller / heater operation / control panel 46 for operation control / safety control operation.

The other branched absorption liquid pipe 48 from the low temperature absorption liquid pump 12 is connected to the low temperature heat exchanger 14, and the absorption liquid is heated by the low temperature heat exchanger 14 and then introduced into the aforementioned exhaust heat recovery unit 30. . The exhaust heat recovery unit 30 is configured to be supplied with exhaust hot water generated by exhaust heat from an external heat source device such as a gas engine, a gas turbine, or an incinerator as a heat source.
The exhaust hot water inlet pipe 50 and the exhaust hot water outlet pipe 52 are provided with hot water temperature sensors 54 and 56, respectively, and these sensors 54 and 56 and the operation / control panel 46 are connected. The drain temperature inlet pipe 50 and / or the drain temperature outlet pipe 52 is provided with, for example, a drain warm water flow rate control valve 58 that is a three-way control valve, and the control valve 58 and the operation / control panel 46 are connected. . Further, an absorption liquid temperature sensor 62 is provided in the absorption liquid pipe 60 at the inlet of the exhaust heat recovery device 30, and the temperature sensor 62 and the operation / control panel 46 are connected to each other. 64 is a second cooling / heating switching valve, and 66 is an overflow weir provided in the refrigerant liquid reservoir 42 of the evaporator 26. It is also possible to use an overflow pipe instead of the weir.

  Next, in the absorption chiller / heater configured as described above, the absorption liquid circulation cycle will be described in order. First, a part of the rare absorbent whose concentration is reduced by absorbing a large amount of refrigerant vapor in the absorber 10 is supplied from the absorber 10 to the low-temperature heat exchanger 14 and heated by the low-temperature heat exchanger 14. After that, it is introduced into the exhaust heat recovery unit 30. The remainder of the absorbing liquid is fed to the refrigerant liquid reservoir 42 of the evaporator 26. The rare absorption supplied to the exhaust heat recovery unit 30 is heated and regenerated by the exhaust hot water, and a part of the absorbed refrigerant is released to increase the concentration accordingly, and the low temperature regeneration is performed via the absorption liquid pipe 68. Sent to the vessel 16. The refrigerant vapor from the exhaust heat recovery unit 30 contains the absorption liquid, and is sent to the low-temperature regenerator 16 and the evaporator 26 via the refrigerant vapor pipes 70 and 72. The second cooling / heating switching valve 64 is provided in the refrigerant vapor pipe 72 to the evaporator.

Most of the intermediate concentrated absorbent regenerated at low temperature in the low temperature regenerator 16 is supplied from the low temperature regenerator 16 to the high temperature heat exchanger 20 by the high temperature absorbent pump 18 and heated by the high temperature heat exchanger 20. It is fed to the high temperature regenerator 22. The intermediate concentrated absorbent is regenerated in the high-temperature regenerator 22 and a part of the absorbed refrigerant is released, and the concentration is further increased to become a concentrated absorbent having a high concentration.
The remainder of the intermediate concentrated absorbent from the low-temperature regenerator 16 is bypass-supplied to the concentrated absorbent pipe that returns to the absorber 10 via the bypass pipe 32. In this way, part or all of the absorption liquid from the low temperature regenerator 16 is supplied to the high temperature heat exchanger 20 by the high temperature absorption liquid pump 18, where the concentrated absorption liquid from the high temperature regenerator 22 and indirect. After the heat is exchanged, the high temperature regenerator 22 is supplied.

In the high temperature regenerator 22, the concentrated absorbent that has been heated and concentrated by the combustion heat of the fuel such as gas fuel is introduced to the heating side of the high temperature heat exchanger 20 to heat the absorbent from the low temperature regenerator 16, and then the low temperature is reduced. It is introduced to the heating side of the heat exchanger 14. The remaining portion of the absorption liquid from the low-temperature regenerator 16 (which may be zero) joins the absorption liquid in the absorption liquid pipe on the heating side from the high-temperature heat exchanger 20 via the bypass pipe 32.
The refrigerant vapor from the high-temperature regenerator 22 is introduced into the heat transfer tube group of the low-temperature regenerator 16 through the refrigerant vapor pipe 74, and the refrigerant drain is introduced into the condenser 24 after heating and concentrating the absorption liquid here.

  The refrigerant vapor from the low temperature regenerator 16 is introduced into the condenser 24 through the refrigerant vapor pipe 76, and the refrigerant drain from the low temperature regenerator 16 is introduced into the condenser 24. Note that a part of the refrigerant drain from the low-temperature regenerator 16 is supplied to the evaporator 26 by opening the first cooling / heating switching valve 38.

  Further, a cold / hot water temperature sensor 78 is provided in the cold / hot water discharge pipe, a steam drain temperature sensor (not shown) is provided in the steam drain pipe from the low temperature regenerator 16, and an absorbing liquid extraction conduit 80 from the high temperature regenerator 22. Is provided with an absorption liquid temperature sensor (not shown), and the refrigerant vapor pipe 74 is provided with a vapor temperature sensor (not shown) and a pressure gauge (pressure sensor (not shown)). The steam drain temperature sensor, the steam temperature sensor, and the steam pressure sensor are not provided at the same time, and any one of them may be provided. Two or more may be provided. The refrigerant line having the refrigerant pump 28 is provided with a refrigerant temperature sensor 82, the cold / hot water inlet line is provided with a cold / hot water temperature sensor 84, and the exhaust gas line of the high-temperature regenerator 22 is provided with an exhaust gas temperature sensor 86. It has been. Reference numeral 88 is a combustion apparatus, and 90 is a fuel flow rate control valve.

  Further, as described above, the operation / control panel 46 is provided. The operation / control panel 46, the absorption liquid flow rate adjustment valve 44, the hot water temperature sensors 54, 56, the exhaust hot water flow rate control valve 58, and the absorption liquid temperature sensor 62 are provided. , Cold / hot water temperature sensors 78, 84, refrigerant temperature sensor 82, steam drain temperature sensor, high-temperature regenerator combustion device 18 or fuel flow control valve 90, exhaust gas temperature sensor 86, absorption liquid temperature sensor for absorption liquid extraction conduit 80, The low-temperature absorption liquid pump 12, the high-temperature absorption liquid pump 18, the vapor temperature sensor of the refrigerant vapor pipe 74, and a pressure gauge (pressure sensor) are connected in an interlocked manner so that the temperature, pressure, flow rate, etc. of these parts can be controlled. ing. Note that the steam drain temperature sensor, the steam temperature sensor, and the steam pressure sensor are not provided at the same time, but any one of them is provided. Two or more may be provided.

In the absorption chiller / heater of the present invention configured as described above, a temperature change on the load side is detected from a chilled / hot water temperature sensor 78 provided in a chilled / hot water outlet pipe from the evaporator 26, and the temperature change is operated / controlled. The control signal from the panel 46 is introduced into the combustion device 88 or the fuel flow control valve 90 to increase or decrease the fuel supplied to the high temperature regenerator 22 and increase or decrease the combustion amount of the combustion device 88 to increase the efficiency of the high temperature regenerator 22. Driving.
At the same time, each of the absorption liquid pumps 12 and 18 is operated to stably supply and circulate absorption liquids having different water content ratios to perform continuous operation. That is, a part of the liquid flowing from the low-temperature regenerator 16 into the high-temperature absorption liquid pump 18 is branched and bypassed by the bypass pipe 32, and the supply / circulation amount of water / absorption liquid is adjusted. Adjusting the power load to be applied, energy saving and stable continuous operation.

  Further, the temperature of the load (cold / hot water) is detected by the cold / hot water temperature sensor 78, and the combustion amount (heating amount) of the combustion device 88 is increased / decreased through the operation / control panel 46, and at the same time, the vapor pressure inside the high-temperature regenerator 22. When the temperature detected by the steam drain temperature sensor at the outlet of the high-temperature regenerator heated by steam rises, the high-temperature absorbing liquid passes through the operation / control panel 46 for safety. If the rotation speed of the pump 18 is increased, the liquid circulation amount is increased, and as a result the vapor pressure is lowered, and the drain temperature detected by the vapor drain temperature sensor decreases, the high-temperature absorbing liquid pump 18 is passed through the operation / control panel 46. The number of circulating fluids is decreased to increase the vapor pressure so that stable operation can be continued in a temperature range and pressure range suitable for continuous operation. Controlling the rotational speed of the low-temperature absorbent pump 12 simultaneously with the high-temperature absorbent pump 18 has the effect of further increasing the corresponding speed. Even if the high-temperature absorbing liquid pump 18 is operated at a constant speed without changing the rotational speed, the flow rate is adjusted by the bypass pipe 32, so that no problem occurs even if the rotational speed is not controlled.

  Moreover, simultaneously with increasing / decreasing the combustion amount (heating amount) of the combustion device 88 due to the temperature change of the load (cold / warm water), the vapor pressure inside the high temperature regenerator 22 rises and the temperature rises, and the high temperature regenerator outlet part If the temperature detected by the steam pipe or the temperature sensor detects that the temperature is detected by the temperature sensor, the rotational speed of the high-temperature absorption pump is increased for safety, and the liquid circulation rate is increased. If the steam pressure or temperature falls, the rotation speed of the high-temperature absorption liquid pump 18 is lowered to reduce the liquid circulation rate to increase the steam pressure, and stable operation continues in the temperature range and pressure range suitable for continuous operation. It can be so. Increasing and decreasing the rotational speed of the high-temperature absorbent pump 18 and simultaneously increasing and decreasing the rotational speed of the low-temperature absorbent pump 12 have the effect of increasing the response speed and improving the controllability.

  Further, when the supply device for supplying water / absorption liquid to the high-temperature regenerator 22 during operation, for example, the high-temperature absorption liquid pump 18 fails and the supply amount is reduced, the supply is held inside the high-temperature regenerator 22. Since the amount of water / absorbed liquid decreases and hinders continuous operation, an alarm is issued and at the same time, combustion is shut off and control is performed to enter a safe stop operation.

  Further, when the amount of water / absorbing liquid supplied to the high temperature regenerator 22 is reduced during operation, or the amount of water / absorbing liquid held in the high temperature regenerator 22 is decreased, the temperature of each part is set to a safe operation set value. If the temperature exceeds the range, the high temperature regenerator 22 or the absorption liquid temperature sensor provided at the absorption liquid outlet of the high temperature regenerator 22 issues an alarm via the operation / control panel 46 and simultaneously shuts off the combustion to stop safety. Control to enter the operation. It is also possible to use a boiler-type high-temperature regenerator such as a once-through boiler instead of the type of high-temperature regenerator 22 that indirectly heats the absorbent with combustion exhaust gas as shown in FIG.

Next, the control flow will be described in more detail. First, cold water outlet (inlet) temperature Tc1 detection → load control calculation → temperature detection of exhaust heat water inlet temperature Th1 and exhaust heat recovery device inlet absorption liquid temperature Tw1 and exhaust heat recovery device outlet hot water temperature Th2 are detected.
Determination condition (1): When Th1−Tw1> set value.
The flow control opening to the exhaust heat recovery device side of the three-way control valve 58 of the exhaust warm water is fully opened, and the entire amount flows to the exhaust heat recovery device 30. After confirming that the opening degree of the control valve 58 is 100%, normal combustion control is performed according to the cold water outlet (inlet) temperature Tc1. Next, load control calculation is performed, and combustion operation output control and operation output control of the three-way control valve 58 of the exhaust water are performed.

3 and 4, the absorption liquid temperature circulating through the chiller / heater changes due to a change in the external load, the absorption liquid temperature Tw1 at the inlet of the exhaust heat recovery unit 30 changes, and the outlet hot water of the exhaust heat recovery unit 30 changes. When the temperature Th2 changes, the opening of the three-way control valve 58 is controlled according to the outlet temperature to change the amount of warm water that flows to the exhaust heat recovery device 30 and the amount of warm water that is bypassed. In FIG. 4, 92 is a heat transfer tube group. Then, the following controls (a), (b), and (c) are performed. As described above, the outlet hot water temperature Th2 is not a fixed value but a variable value. That is, the temperature range and temperature from 60 ° C. to 83 ° C. shown as an example in FIG. 3 may be changed from 65 ° C. to 80 ° C., for example. With respect to 60 ° C. when the valve opening degree is 0% and 83 ° C. when the valve opening degree is 100%, there is a possibility that the setting of the temperature width and the outlet temperature may be changed depending on the request of the customer.
(A) The upper-limit peak cut control of the three-way control valve 58 of the waste water is performed according to the waste water outlet temperature.
(B) The peak cut value is proportionally controlled by the exhaust water outlet temperature.
(C) The amount of heat shortage due to the peak cut of the waste water is increased and controlled. When the amount of heating is smaller than the load by the load control calculation, the combustion control amount is increased to correct the shortage of the exhaust hot water amount.

Further, when the heating amount is larger than the load, the amount of combustion control is reduced and control is performed so that the chilled water cooler outlet (inlet) temperature Tc1 is stabilized at the set temperature. If the amount of heat (exhaust heat recovery amount) is larger than the load even if the combustion heat amount is zero, and the chilled water outlet (inlet) temperature Tc1 decreases and is not stable at the set temperature, the absorption liquid flow rate that causes the absorbent to flow into the evaporator The control valve 44 is opened to allow the absorption liquid to flow into the refrigerant reservoir 42 of the evaporator 26, and the refrigerant accumulated in the refrigerant reservoir 42 of the evaporator and the flowing absorption liquid are absorbed from an overflow weir 66 provided in the evaporator. Spill (return) to 10 absorbent reservoir 94.
For example, the absorption liquid flow rate adjusting valve 44 is opened for 5 seconds and then fully closed to check the cold water temperature Tc1 and determine whether to open the valve 44 again. The function of checking the passage of time and the change of the cold water temperature Tc1 is provided. Since it is incorporated in the control device and includes a control that prevents the absorption liquid from flowing into the refrigerant pool more than necessary, the chilled water temperature is prevented from excessively rising. Therefore, the adverse effect on the external heat source device side is reduced, and the adverse effect on the cooling load side is also reduced, thereby preventing energy loss.

  Mixing the absorption liquid into the refrigerant in the refrigerant reservoir 42 and spilling (returning) the refrigerant and the absorption liquid into the absorption liquid reservoir 94 to prevent the cold water outlet (inlet) temperature from being excessively lowered and the operation of the safety device, and By continuing the flow of the exhaust warm water, the return temperature of the exhaust warm water is stabilized and the adverse effect on the gas engine side is reduced. In addition, the absorption liquid that exchanges heat with the waste water does not fall too much due to the heat of the waste water, so the rise when the load increases while the operation continues is quick and the fuel is burned off. Since it can be reduced, the energy saving effect can be increased by effectively using the exhaust heat.

Judgment condition (2): When Th1-Tw1 <setting value, or when Th1-Tw1 = setting value. The flow control circuit to the exhaust heat recovery device 30 side of the three-way control valve 58 of the exhaust warm water is fully closed, and the exhaust heat recovery device 30 is bypassed for the entire amount. At this time, when there is a cooling load and there is a combustion operation output signal to the heating source, normal fuel combustion control is performed.
Other conditions include a control operation that enables the combustion control operation after the exhaust hot water control valve 58 is fully opened before the start of combustion when the exhaust hot water control is possible at the time of startup. At the time of stop, the three-way control valve 58 of the exhaust hot water is fully closed, and the exhaust hot water is not sent to the exhaust heat recovery device 30, but the entire amount is bypassed.

When the generator load is large and the amount of exhaust heat is large, and the cooling load is small, the amount of heat collected by the chiller / heater decreases, so the temperature of the exhaust water returning to the gas engine rises. Moreover, the cold water temperature cooled by the cold / hot water machine may be too low. In this case, it is possible to prevent the cold water temperature from being excessively lowered by controlling the above-described absorption liquid to be injected into the refrigerant, but it is not possible to completely control the exhaust hot water temperature. For this reason, it is a matter of course that a separate cooling device for releasing the exhaust heat to the atmosphere is required, as used in the conventional system.
By providing the cold / hot water machine of the present invention, it becomes possible to cope with the case where external heat source equipment, for example, a gas engine is operated alone and exhausted hot water is generated while the cold / hot water machine is stopped. In view of this, it can be said that the configuration of the present invention is a device that must be equipped.
In addition, although FIG. 1 demonstrated the case of the double effect type absorption chiller-heater, of course, this invention is applicable also to a single effect type (single effect type) absorption chiller / heater.

It is a systematic schematic block diagram of the double effect type absorption chiller / heater having the exhaust heat recovery device according to the first embodiment of the present invention. It is for demonstrating the control method in the cold / hot water machine of this invention, and is a graph which shows the relationship between time, cold water exit temperature, and refrigerant | coolant temperature. It is for demonstrating the control method in the cold / hot water machine of this invention, and is a graph which shows the relationship between waste water outlet temperature and the three-way control valve opening degree of waste water. It is an expansion explanatory view around a three-way control valve of an exhaust heat recovery device and exhaust heat warm water. It is a systematic schematic block diagram which shows an example of the conventional absorption-type cold water heater.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Absorber 12 Low temperature absorption liquid pump 14 Low temperature heat exchanger 16 Low temperature regenerator 18 High temperature absorption liquid pump 20 High temperature heat exchanger 22 High temperature regenerator 24 Condenser 26 Evaporator 28 Refrigerant pump 30 Waste heat recovery device 32 Bypass pipe 34 Cold temperature Water pump 36 Cooling water pump 38 First cooling / heating switching valve 40 Branch absorption liquid pipe 42 Refrigerant liquid reservoir 44 Absorption liquid flow rate adjustment valve 46 Absorption type chiller / heater operation / control panel 48 Branch absorption liquid pipe 50 Waste water inlet pipe 52 Waste water Outlet pipe 54, 56 Hot water temperature sensor 58 Waste water flow control valve (3-way control valve)
60 Absorbing liquid pipe 62 Absorbing liquid temperature sensor 64 Second cooling / heating switching valve 66 Overflow weir 68 Absorbing liquid pipe 70, 72, 74, 76 Refrigerant vapor pipe 78, 84 Cold / hot water temperature sensor 80 Absorbing liquid extraction conduit 82 Refrigerant temperature sensor 86 Exhaust gas temperature sensor 88 Combustion device 90 Fuel flow control valve 92 Heat transfer tube group 94 Absorption liquid reservoir

Claims (16)

Absorber, low-temperature regenerator, high-temperature regenerator, evaporator, condenser, absorption liquid heat exchanger, absorption liquid pump, refrigerant pump, etc. In the reverse flow double-effect absorption chiller / heater, the absorption liquid of the absorber is guided to the low temperature regenerator, and then the absorption liquid of the low temperature regenerator is guided to the high temperature regenerator. An exhaust heat recovery unit is installed in front of the low-temperature regenerator to recover the exhaust heat and use it as a heating source to heat the absorption liquid and heat and evaporate the refrigerant absorbed in the absorption liquid to increase the concentration of the absorption liquid. By reducing the amount of heat generated by heating the absorption liquid in the low-temperature regenerator and increasing the concentration of the absorption liquid by controlling the amount of exhaust heat recovered from the outside, the heat exchange amount of the low-temperature regenerator is reduced and the temperature is increased. Heating and concentrating the absorption liquid generated in the regenerator to heat the low-temperature regenerator Reduce the amount of generation of the refrigerant vapor to be to allow exhaust heat recovery operation in response to the heating and cooling loads change, the exhaust heat recovery device is flushed with discharge hot water, combustion heat reduction during operation to recover the waste heat, and During partial load operation that does not require reheating combustion operation with a high-temperature regenerator combustion device, the absorption pump is operated at rated operation to increase the amount of absorption liquid circulation so as to maximize the amount of exhaust heat recovery. If the load increases and the reheating combustion operation becomes necessary, the discharge amount of the absorption liquid pump is controlled so that the absorption liquid circulation amount can be efficiently operated according to the load. A double-effect absorption chiller / heater having a waste heat recovery device, characterized in that consumption of high-grade heating fuel used for heating in a high-temperature regenerator is reduced to save energy. Absorber, low-temperature regenerator, high-temperature regenerator, evaporator, condenser, absorption liquid heat exchanger, absorption liquid pump, refrigerant pump, etc. In the reverse flow double-effect absorption chiller / heater, the absorption liquid of the absorber is guided to the low temperature regenerator, and then the absorption liquid of the low temperature regenerator is guided to the high temperature regenerator. An exhaust heat recovery unit is installed in front of the low-temperature regenerator to recover the exhaust heat and use it as a heating source to heat the absorption liquid and heat and evaporate the refrigerant absorbed in the absorption liquid to increase the concentration of the absorption liquid. By reducing the amount of heat generated by heating the absorption liquid in the low-temperature regenerator and increasing the concentration of the absorption liquid by controlling the amount of exhaust heat recovered from the outside, the heat exchange amount of the low-temperature regenerator is reduced and the temperature is increased. Heating and concentrating the absorption liquid generated in the regenerator to heat the low-temperature regenerator The exhaust heat recovery operation according to the change in the heating / cooling load can be performed even if the generation amount of the refrigerant vapor is reduced, the exhaust heat water is passed through the exhaust heat recovery device, and the exhaust heat recovery operation is being performed. During partial load operation that uses a high-temperature regenerator combustion device to perform reheating combustion, the liquid level of the solution in the high-temperature regenerator does not fluctuate due to load fluctuations, etc. to prevent a safe stop due to empty can operation or low liquid level In addition, by controlling the discharge rate of the absorption liquid pump to ensure the amount of absorption liquid circulation to the high-temperature regenerator so that it can be operated continuously and stably, high-grade heating used for heating in the high-temperature regenerator A double-effect absorption chiller / heater having an exhaust heat recovery device characterized by reducing fuel consumption and saving energy. When the heating / cooling load fluctuates in the range of 100 to 0% by controlling the amount of exhaust heat recovered from the outside, the ratio of the heating heat amount that heats the absorbing solution and raises the concentration of the absorbing solution in the low temperature regenerator, 15 to 100 A double-effect absorption chiller / heater having an exhaust heat recovery device according to claim 1 or 2 that is reduced by%. Compared to the double-effect absorption chiller / heater without a waste heat recovery unit, a high-temperature heating fuel consumption used for heating in a high-temperature regenerator can be operated at a rated load by providing a waste heat recovery unit. The double-effect absorption system having an exhaust heat recovery device according to claim 1 , wherein the energy is reduced by 15 to 30% during operation and 15 to 100% during low-load operation so as to save energy. Type water heater. The exhaust heat recovery device according to any one of claims 1 to 4 , further comprising an exhaust hot water control valve, an exhaust hot water conduit, and an exhaust hot water controller for recovering external exhaust heat to be used as a heat source for the exhaust heat recovery device. Has a double-effect absorption cold / hot water machine. When the temperature of the exhaust water at the inlet of the exhaust heat recovery unit is higher than the absorption liquid temperature to be heated in the exhaust heat recovery unit by controlling the exhaust temperature control valve, the exhaust warm water flows into the exhaust heat recovery unit and the absorption liquid is removed. A double-effect absorption chiller / heater having the exhaust heat recovery device according to claim 5 , which is heated. Three-way valve opening upper limit peak cut control for the return waste water temperature so that the temperature of the waste water does not adversely affect the operating conditions and efficiency of the heat source system equipment that is the heat source that generates external waste heat A double-effect absorption chiller / heater having a waste heat recovery device according to claim 6 , wherein the exhaust heat water flows into the waste heat recovery device by a predetermined amount and heats the absorption liquid. A double-effect absorption type having an exhaust heat recovery unit according to claim 7 , wherein a three-way valve for controlling the flow rate of exhaust heat hot water is provided at the exhaust heat recovery unit inlet, and the upper limit peak cut control of the three-way valve is a proportional control type. Cold and hot water machine. In the case where the flow rate control of the exhaust heat water entering the exhaust heat recovery unit is performed and the peak cut control of the exhaust heat water is performed, and if the heating amount is insufficient for the demand of the air conditioning load, the amount of combustion is increased and controlled. Item 8. A double-effect absorption chiller / heater having the exhaust heat recovery device according to Item 7 . The exhaust heat recovery according to any one of claims 1 to 9 , wherein a selection specification is provided so that the operation mode can be switched so that the operation is started from the combustion control operation at the time of startup when there is no heating by external exhaust heat. Double-effect absorption chiller / heater with a vacuum vessel. The absorption pump outlet of the absorber and the evaporator are connected via an absorption liquid distribution pipe having a flow control valve, and the temperature sensor provided in the cold water outlet pipe or the cold water inlet pipe of the evaporator and the flow control valve are connected. Via the control device, it is possible to control the amount of absorption liquid to be injected into the evaporator according to the temperature detected by the cold water temperature sensor, and further, the refrigerant accumulated in the evaporator refrigerant reservoir and the absorbed liquid flowing in are provided in the evaporator. The double-effect absorption chiller / heater having the exhaust heat recovery device according to any one of claims 1 to 10 , wherein the drainage heat sink is caused to flow down or return from an overflow weir or an overflow pipe. Monitor the refrigerant temperature sprayed by the evaporator, the refrigerant temperature in the evaporator refrigerant pool and the cold water outlet temperature, and either the refrigerant temperature before the absorption liquid injection, the refrigerant temperature after the absorption liquid injection or the cold water outlet temperature or both The double-effect absorption having an exhaust heat recovery device according to claim 11 , wherein the temperature difference is compared, and the injection amount is controlled by the absorption liquid flow rate control valve so that the temperature difference (Δt ° C) does not exceed a set value. Type water heater . Exhaust heat recovery device is, exhaust hot water flows through the tube is a heating fluid, to any one of claims 1 to 12, which is a shell-and-tube heat exchanger of the pool boiling system through the outer tube is diluted absorption solution A double-effect absorption chiller / heater having the exhaust heat recovery device described. The rare-boiling liquid outlet of the pool boiling type shell and tube heat exchanger is provided near the uppermost stage of the heat transfer tube group constituting the shell and tube type heat exchanger, and the heat transfer tube group 14. The exhaust heat according to claim 13 , wherein the arrangement of the heat transfer tubes in the uppermost stage and the lower stage is configured not to inhibit the surfactant added to the absorbent from flowing out from the rare absorbent outlet. Double-effect absorption chiller / heater with a collector. The double-effect absorption chiller / heater having a waste heat recovery device according to claim 14 , wherein the arrangement of the heat transfer tubes at the uppermost stage and the lower stage of the exhaust heat recovery device is arranged in a grid pattern. A branch line connected to the heating side of the evaporator is provided in the refrigerant vapor line from the exhaust heat recovery device to the low temperature regenerator, and cooling / heating switching means for switching between cooling and heating is provided in the branch line, and the cooling / heating switching is performed. The method according to any one of claims 1 to 15 , wherein the means is switched to heating and the refrigerant vapor from the exhaust heat recovery device is led to the evaporator to heat the hot water flowing in the heat transfer pipe in the evaporator. Double-effect absorption chiller / heater with exhaust heat recovery unit.

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