JP2921372B2 - Double-effect absorption heat pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a double-effect absorption heat pump.

[0002]

2. Description of the Related Art Conventional double-effect absorption heat pumps are:
Under the conditions where the low-temperature heat source temperature is low and the absorption solution concentration is relatively high, if you try to take out hot water at the temperature required for heating, the high-temperature regenerator pressure will exceed atmospheric pressure, and the pressure vessel will need to be recharged. However, the temperature of the hot water could not be raised to a temperature required for heating.

For this reason, as described in JP-A-5-52438 or JP-A-5-52439, an intermediate-temperature heat medium is produced by a double-effect heat pump cycle, and the intermediate-temperature heat medium is supplied to a low-temperature heat source. As a method, a single-effect heat pump was operated to take out hot water at a high temperature. When the temperature is raised in two stages in this manner, high-temperature hot water can be taken out, but there is a disadvantage that the coefficient of performance (COP) is low.

For example, the highest COP at present is COP = 2.2 for a double-effect absorption heat pump and COP = 1.7 for a single-effect absorption heat pump.

[0005]

(Equation 1)

As a result, only 29% of the heating heat can use the exhaust heat.

[0007]

According to the above-mentioned conventional technology, high-temperature hot water can be taken out, but the thermal efficiency is low.
There was a problem that the waste heat utilization rate was small.

An object of the present invention is to recover heat from a relatively low exhaust heat source, efficiently produce hot water having a temperature required for heating,
An object of the present invention is to provide a double-effect absorption heat pump having high utilization of waste heat.

Another object of the present invention is to provide a double-effect absorption heat pump capable of extracting hot water at a constant temperature level required for heating even when the temperature of the exhaust heat source is lowered.

[0010]

In order to achieve the above object, a condenser for directly condensing and heating hot water with refrigerant vapor generated from a high-temperature regenerator is provided at a hot water outlet side of a double effect absorption heat pump, and condensed and liquefied. refrigerant back to the evaporator through a condenser which constitutes a double-effect absorption heat pump, a further
Hot water is generated by the heat of condensation of the refrigerant vapor generated by the high-temperature regenerator.
The hot water line of the condenser to be heated is passed through the condenser to bypass the condenser.
And the condenser is bypassed by the pressure of the high-temperature regenerator.
The amount of hot water passed is controlled .

[0011] In addition, in order to achieve the above Symbol purpose, double-effect
The hot-water outlet side of the absorption heat pump, originating from the low temperature regenerator
A condenser that directly condenses and heats hot water with the generated refrigerant vapor is installed.
Heat and condensed and liquefied refrigerant into a double-effect absorption heat pump.
It is obtained by the Suyo back to the evaporator through the condenser constituting.

[0012] In addition, in order to achieve the above Symbol purpose, the evaporator
Under the condition that the temperature of the low-temperature heat source water flowing into the furnace falls and the concentration of the absorbing solution is increased, when the absorbing solution concentration becomes higher than a certain level, the refrigerant liquid of the evaporator automatically enters the absorber side, and the solution of the absorbing solution is removed. It is designed not to become darker than a certain level.

[0013]

[Function] A condenser that directly guides refrigerant vapor generated in a high-temperature regenerator and condenses and liquefies by heating hot water is an evaporator,
Combined with the absorber, it constitutes a single-effect absorption heat pump cycle. Therefore, when the temperature of the exhaust heat source is low and the concentration of the absorbing solution is high, and the solution concentration in the low-temperature regenerator is high and the solution temperature is high, the high-temperature regenerator pressure is large in the double effect absorption heat pump cycle. If the hot water is heated by an absorber and a condenser within a range not exceeding the atmospheric pressure, and the portion of the hot water that does not reach a predetermined temperature is heated by a condenser that condenses and liquefies the refrigerant vapor generated in the high-temperature regenerator, This means that heating is performed by the utility absorption heat pump cycle,
OP becomes an intermediate value between the single-effect absorption heat pump cycle and the double-effect absorption heat pump cycle, and the utilization rate of exhaust heat increases.

Further, when the temperature of the exhaust heat source is relatively high, the concentration of the absorber solution becomes low, so that the hot water can be heated to near a predetermined temperature by the double effect absorption heat pump cycle. In this case, when the hot water passing through the condenser for condensing and liquefying the refrigerant vapor generated in the high-temperature regenerator is bypassed and the amount of condensation is reduced, the rate of heating by the double effect absorption heat pump cycle increases, and the overall COP Will be higher. Further, since the amount of hot water bypass of the condenser is controlled by the pressure of the high-temperature regenerator, the rate of heating by the double effect absorption heat pump cycle should be maximized as long as the high-temperature regenerator pressure does not exceed the atmospheric pressure. As the exhaust heat source temperature condition changes, the most efficient operation under that condition is performed.

[0015] When the temperature of the exhaust heat source drops and the concentration of the absorber solution becomes higher than a certain level, the refrigerant liquid automatically flows into the absorber solution from the evaporator so that the solution concentration does not become higher than the certain level. If the solution does not crystallize, the absorption heat pump acts as a heat exchanger that uses all of the heat from the drive source to heat the hot water, and COP = 1. When the temperature of the exhaust heat source rises, a part of the evaporator evaporates, and the COP becomes 1 or more. When the temperature of the exhaust heat source further rises, the COP becomes high and reaches a maximum of 2.2. In other words, when an absorber heat pump with an evaporator that directly guides and condenses the refrigerant vapor generated in the high-temperature regenerator, when the concentration of the absorber solution becomes higher than a certain level, the refrigerant liquid is automatically transferred from the condenser to the absorber solution. The provision of the inflow device enables operation without heat loss even when the temperature of the exhaust heat source greatly changes.

[0016]

An embodiment of the present invention will now be described with reference to FIGS.
This will be described with reference to the drawings. Low-temperature heat source water 2 as a low-temperature heat source flows through the heat transfer tube passing through the evaporator 1, and the refrigerant outside the tube is dispersed by the refrigerant pump 3 onto the heat transfer tube, and heat is transferred from the low-temperature heat source water 2 flowing inside the tube. Take away and evaporate. The evaporated refrigerant reaches the absorber 4 and is absorbed by the solution maintained at an appropriate temperature and concentration by the hot water 5 flowing in the pipe, and the solution is diluted. The diluted solution is sent to a low-temperature regenerator 7 and a high-temperature regenerator 8 by a solution pump 6, where the solution is heated and concentrated by an external heat source 9. The refrigerant vapor generated at this time reaches the inside of the tube of the low-temperature regenerator 7, heats and concentrates the dilute solution outside the tube, liquefies itself, and flows into the condenser 10. The liquids concentrated in the high-temperature regenerator 8 and the low-temperature regenerator 7 are combined, returned to the absorber 4, and sprayed on the heat transfer tube. The refrigerant liquid condensed in the condenser 10 and the low-temperature regenerator 7 returns from the condenser 10 to the evaporator 1, and the cycle goes around.
The hot water passing through the absorber 4 and the condenser 10 is heated by obtaining heat of absorption and heat of condensation, and is used for heating or heating.

The second condenser 11 is further heated by passing the hot water heated by the condenser 10 into the heat transfer tube and introducing the refrigerant vapor generated from the high-temperature regenerator 8 outside the tube to condense. Raise the temperature. The refrigerant vapor generated in the high-temperature regenerator 8 has a high saturation temperature at which the dilute solution can be heated and concentrated in the low-temperature regenerator 7, and thus has a potential to heat hot water to about 90 ° C. The control valve 17 regulates the amount of hot water passing through the second condenser 11,
Adjust the amount of heating.

In response to the signal from the pressure detector 15 of the high-temperature regenerator 8, the pressure regulator 16 increases the amount of hot water passing through the second condenser 11 when the pressure of the high-temperature regenerator 8 becomes close to the atmospheric pressure. The heating amount is increased, and when the pressure is low, on the other hand, control is performed so as to decrease the amount of heating by decreasing the amount of hot water passing therethrough.

The control valve 14 for controlling the input of the heating source is operated by the signal of the temperature controller 13 which receives and controls the signal of the temperature sensor 12 at the hot water outlet, and controls the hot water outlet temperature to be constant.

In a heat pump having such a configuration, the outlet temperature of hot water is often set to around 50 ° C. when used for general heating purposes, and the higher the temperature, the higher the temperature.
Even if the heat transfer area of the air conditioners is reduced, there is an advantage that a required amount of heating can be obtained and the power for transferring hot water can be reduced.

On the other hand, when viewed from the absorption heat pump side, in the double effect cycle, the outlet temperature of the hot water of the condenser 11 determines the condensation pressure of the refrigerant in the condenser 11. The refrigerant evaporation pressure generated in the low-temperature regenerator 7 communicating with the refrigerant increases. When the refrigerant evaporation pressure increases, the temperature of the solution in equilibrium with the refrigerant evaporation increases, so that the condensation temperature of the refrigerant vapor in the pipe that heats the solution increases, and the saturation pressure with respect to the condensation temperature is equal to the pressure of the high-temperature regenerator. Therefore, the pressure of the high-temperature regenerator 8 increases.

In summary, the relationship is established that the higher the hot water outlet temperature, the higher the pressure of the high-temperature regenerator 8.

These relationships will be described with reference to the During diagram shown in FIG. 2. For example, the outlet temperature of the low-temperature heat source water (te
o) is 10 ° C and the hot water outlet temperature (thc) is 47 ° C,
The solution concentration of the absorber 4 becomes about 58%, the refrigerant condensation temperature (Tc) of the condenser 11 is 48.5 ° C., and the saturation pressure (Pc) is 8
6 mmHgabs, and the solution temperature at the low temperature regenerator outlet is 97
° C, the refrigerant condensation temperature (Tgc) in the pipe becomes 100 ° C,
The high temperature regenerator pressure (PHG) is at atmospheric pressure. When the temperature level of the low-temperature heat source water rises and the low-temperature heat source water outlet temperature (teo) becomes about 15 ° C., the evaporation pressure (Pe) rises, so that the solution concentration of the absorber 4 becomes about 56%. Also, the solution temperature at the outlet of the low-temperature regenerator falls to 93 ° C., and the pressure of the high-temperature regenerator also becomes lower than the atmospheric pressure.

As described above, when low-temperature wastewater such as sewage treatment water is used as a low-temperature heat source, in order to obtain a high-temperature hot water temperature required for heating in a double effect cycle, the high-temperature regenerator pressure becomes atmospheric pressure. That is all.

If the inside of the machine exceeds the atmospheric pressure, the entire absorption heat pump becomes a pressure vessel, and strict safety considerations are required, so that an expensive heat pump is required, and special qualifications are required for a driver who operates the heat pump. And other safety problems. Therefore, in actual heat pumps, a safety switch is provided to stop the machine or the hot water outlet temperature is reduced by limiting the load so that the operating pressure does not exceed the atmospheric pressure. .

In the present invention, a part of the refrigerant vapor generated in the high-temperature regenerator 8 is guided to the second condenser 11, and the hot water discharged from the condenser 10 is supplied to the outside of the heat transfer tube of the second condenser 11. To heat with the condensation heat of the refrigerant vapor.

With this arrangement, when the temperature of the hot water at the outlet of the second condenser 11 is set at 47 ° C.,
The outlet hot water temperature of 0 becomes about 45 ° C., and the internal pressure of the high-temperature regenerator can be made sufficiently lower than the atmospheric pressure.

The refrigerant liquid condensed and liquefied by heating the hot water in the second condenser 11 passes through the condenser 10
Since the heat is returned to the evaporator 1, the evaporator 1 is used for pumping heat from a low-temperature heat source. That is, the heat of condensation used for heating the hot water in the second condenser 11 acts as a single-effect cycle and is effectively used for heat recovery from a low-temperature heat source. As described above, the coefficient of performance of a single-effect cycle heat pump is about 1.7.

On the other hand, the heat of condensation used for heating the hot water in the condenser 10 acts as a double-effect cycle, increasing the efficiency of heat recovery from the low-temperature heat source, and the coefficient of performance as a heat pump is about 2.2. . Therefore, the overall coefficient of performance increases when the amount of heated hot water in the second condenser 11 is reduced and the amount of heated hot water in the condenser 10 is increased. For example, as described above, when the temperature of the low-temperature heat source is high and the solution concentration of the absorber 4 is low, the temperature of the hot water can be raised to a predetermined temperature in the condenser 10, so that the heating amount in the second condenser is reduced to zero. Yes, the highest coefficient of performance is 2.2. Conversely, when the temperature of the low-temperature heat source is low, the concentration of the solution in the absorber increases, so that the condenser 10
The amount of heating in the second condenser must be increased so that the heating amount in the second condenser does not exceed the atmospheric pressure in the high-temperature regenerator. In this case, the coefficient of performance of the heat pump becomes low, and the amount of heating of the condenser 10 becomes 0, which is a minimum of 1.7. That is,
The coefficient of performance is 1.7 depending on the amount of heating in the second condenser 11.
~ 2.2.

The amount of heated hot water in the second condenser 11 can be adjusted by controlling the control valve 17 for adjusting the amount of hot water that bypasses the second condenser 11. Control of the control valve 17 is performed by the pressure detector 1 of the high-temperature regenerator 8.
The signal of No. 5 is supplied to the controller 16 so that the bypass amount is reduced when the high-temperature regenerator pressure is high, and the bypass amount is increased when the high-temperature regenerator pressure is low.

With the above control, the pressure of the high-temperature regenerator 8 of the absorption heat pump can be reduced to the atmospheric pressure or lower, and the operation can be performed at the point having the highest coefficient of performance in accordance with the temperature level of the low-temperature heat source.

FIG. 3 shows another embodiment. All of the refrigerant vapor generated in the high-temperature regenerator 8 flows into the low-temperature regenerator 7,
A part of the solution in the low-temperature regenerator 7 is condensed by heating, and a part thereof is condensed to form a refrigerant liquid and flows into the condenser 10. The refrigerant vapor that has not been condensed is separated from the refrigerant liquid by the separator 19, The hot water is directly heated, condensed and liquefied, and flows into the condenser 10 via a gas blow-through prevention float valve 18. With this configuration, the heat of the superheat of the refrigerant vapor generated in the high-temperature regenerator 8 (about 5
%) Can be used for heating the solution in the low-temperature regenerator 7, and a high coefficient of performance can be obtained even when the low-temperature heat source temperature is low.

FIG. 4 shows still another embodiment. When the temperature of the low-temperature heat source decreases, the evaporation temperature (TE) decreases and the evaporation pressure (PE) decreases, so that the concentration of the absorbing solution increases. When the low-temperature heat source temperature becomes extremely low, the absorption capacity is lost, and the refrigerant in the absorbing solution is separated and the solution concentration is increased, and at the same time, the amount is reduced. On the other hand, in the evaporator 1, the amount of the refrigerant separated from the solution increases, and the liquid level increases. The refrigerant return device 20 is a device for returning the refrigerant liquid to the absorber 4 when the refrigerant liquid level of the evaporator 1 becomes higher than a certain level. By adjusting the mounting level, the solution is prevented from becoming more than an arbitrary concentration. be able to. For example, when the low-temperature heat source temperature is low and the refrigerant liquid level becomes equal to or higher than the level of the refrigerant return device 20, the refrigerant flows from the evaporator 1 into the absorber 4, and the solution concentration does not become more than a certain concentration and no crystals are generated. The circulation of the solution is continued, and the solution exchanges heat with the hot water 5 and is maintained at a constant temperature. In the low-temperature regenerator 7, the solution is heated by the refrigerant vapor generated in the high-temperature regenerator 8, but the refrigerant is hardly regenerated. Most of the refrigerant vapor generated in the high-temperature regenerator 8 heats the hot water in the second condenser 11, condenses and liquefies, and flows into the condenser 10. At this time, the control valve 17 is controlled by the high-temperature regenerator pressure to increase the amount of hot water passing through the second condenser 11, so that the high-temperature regenerator pressure is kept at or below the atmospheric pressure. All the heat that has entered the heat pump from the heat source 9 is transmitted to the hot water 5 and does not escape to the outside.

FIG. 5 shows still another embodiment. Upon receiving the signal from the low temperature heat source water outlet temperature detector 21, the temperature controller 2
2 controls the refrigerant blow valve 23. The operation is such that when the temperature of the low-temperature heat source water is too low, the refrigerant blow valve 23 is opened, the refrigerant is blown to the absorber 4, and the absorption capacity is reduced to prevent the low-temperature heat source water from being supercooled. This is useful for preventing supercooling of the low-temperature heat source water when the low-temperature heat source water temperature is low and the inlet temperature of the hot water 5 is low.

[0035]

According to the present invention, even if the temperature level of the low-temperature heat source changes, hot water of a constant temperature can be taken out, and the operation can be performed with the highest coefficient of performance in accordance with the load and the low-temperature heat source temperature level.

If the temperature of the low-temperature heat source is equal to or higher than a certain
P ranges from 1.7 to 2.2, which is 1.3 to 1.3
1.7 times.

Further, since the heat pump uses the exhaust heat as a low-temperature heat source, it is necessary that the temperature condition is not constant and the heat pump can be operated in a wide temperature range. Can drive to the range that could not be done.

[Brief description of the drawings]

FIG. 1 is a cycle flow diagram showing one embodiment of the present invention.

FIG. 2 is a During diagram showing a relationship between a hot water outlet temperature, a low-temperature heat source temperature, and a high-temperature regenerator pressure.

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

FIG. 4 is a diagram showing still another embodiment of the present invention.

FIG. 5 is a diagram showing still another embodiment of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 evaporator, 2 low-temperature heat source water, 3 refrigerant pump, 4 absorber, 5 hot water, 6 solution pump, 7 low-temperature regenerator, 8
... High temperature regenerator, 9 ... Heat source, 10 ... Condenser, 11 ... Second condenser, 12 ... Hot water outlet temperature detector, 13 ... Hot water outlet temperature controller, 14 ... Heat reduction control valve, 15 ... High temperature regenerator Pressure detector, 16: Pressure controller, 17: Hot water control valve, 18: Float valve, 19: Separator, 20: Refrigerant return device, 21: Low temperature heat source water outlet temperature detector, 22: Low temperature heat source water outlet temperature control 23, refrigerant blow valve in total.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F25B 15/00 303 F25B 30/04 520 F25B 15/00 306

Claims (6)

(57) [Claims] 1. A double-effect absorption heat pump comprising an evaporator, an absorber, a low-temperature regenerator, a condenser constituting a double-effect cycle, a high-temperature regenerator, a solution pump, a refrigerant pump, and piping connecting these. A second condenser for directly introducing and condensing and liquefying the refrigerant vapor generated from the high temperature regenerator is provided downstream of the condenser constituting the double effect cycle, and hot water is supplied to the absorber and the double effect cycle. After heating in the condenser constituting the second condenser, heating is performed in the second condenser, and a passage for introducing the refrigerant liquid condensed in the second condenser to the condenser constituting the double effect cycle is provided. Bypass some of the warm water entering the second condenser
A passage is provided, and this bypass passage is connected to the outlet side of the second condenser.
And the hot water is bypassed by the pressure of the high-temperature regenerator.
A double-effect absorption heat pump comprising a control means for increasing and decreasing the amount . 2. A double effect absorption heat pump comprising an evaporator, an absorber, a low temperature regenerator, a condenser constituting a double effect cycle, a high temperature regenerator, a solution pump, a refrigerant pump, and a passage connecting these. The refrigerant vapor generated in the high-temperature regenerator is introduced into the low-temperature regenerator, and the vapor discharged from the low-temperature regenerator is introduced into the second condenser to be condensed and liquefied. Provided downstream, the hot water is heated by the absorber and the condenser constituting the double effect cycle, then heated by the second condenser, and the refrigerant liquid condensed by the second condenser is cooled by the double effect. A double-effect absorption heat pump characterized in that a passage for introducing into a condenser constituting a cycle is provided. 3. A according to claim 2, wherein the double effect absorption heat pump, a passage for bypassing a portion of hot water entering the second condenser is provided, merging the bypass passage on the outlet side of the second condenser And a control means for increasing or decreasing the bypass amount of hot water by the pressure of the high-temperature regenerator. 4. A second aspect of the double effect absorption heat pump, providing a float valve in the middle of the passage for introducing a refrigerant liquid condensed in the second condenser to the condenser which constitute the double-effect cycle A double-effect absorption heat pump characterized by the following: 5. A double effect absorption heat pump comprising an evaporator, an absorber, a low temperature regenerator, a condenser constituting a double effect cycle, a high temperature regenerator, a solution pump, a refrigerant pump, and piping connecting these. A second condenser for directly introducing and condensing and liquefying the refrigerant vapor generated from the high-temperature regenerator is provided downstream of the condenser constituting the double effect cycle, and hot water is supplied to the absorber and the double effect cycle. After heating in the constituent condenser, heating is performed in the second condenser, and a refrigerant liquid condensed in the second condenser is provided to the condenser forming the double effect cycle. A means for mixing the refrigerant liquid of the evaporator with the absorption solution of the absorber when the amount of the refrigerant becomes constant or more. 6. An evaporator, an absorber, a low-temperature regenerator, a double effect
Condenser, high temperature regenerator, solution pump, cold
Double with medium pump and piping to connect them
In the utility absorption heat pump, from the high temperature regenerator
Secondly, the generated refrigerant vapor is directly introduced and condensed and liquefied.
A condenser downstream of the condenser constituting the double-effect cycle
In the absorber and the double-effect cycle.
After heating in the forming condenser, heating in this second condenser
The refrigerant liquid condensed in the second condenser is subjected to the double effect.
A passage for introducing into a condenser constituting a cycle is provided, and the temperature of the low-temperature heat source water flowing into the evaporator is controlled by the temperature of the evaporator.
A control means to increase or decrease the amount of the medium mixed with the absorbing solution of the absorber
Double effect absorption type heat pon characterized by providing a step
H.