JPH0340301B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dual-effect absorption heat pump cycle that operates at a high-temperature regenerator pressure below atmospheric pressure even at higher hot water temperatures than conventional ones.

As shown in Fig. 1, in a conventional dual-effect absorption heat pump, hot water 12 is first passed through the absorber 1 and then passed through the condenser 4 to obtain hot water at a higher temperature. Ta. Therefore, the dual-effect absorption refrigerator cycle is a cycle in which only the cooling water temperature is increased, and as the cooling water temperature becomes higher, the intermediate solution concentration in the low temperature regenerator 3 becomes higher and the temperature also becomes higher. Along with this, it is necessary to increase the temperature (pressure) of the refrigerant vapor generated in the high temperature regenerator 5 for heating the low temperature regenerator solution 21, so the pressure in the high temperature regenerator 5 becomes higher than before, and the high temperature regenerator Under pressure conditions below atmospheric pressure, it was not possible to raise the hot water outlet temperature. In addition, when hot water is passed through the condenser 4 and the absorber 1 in this order, the pressure in the condenser 4 decreases, but the temperature of the hot water 12, which serves as the cooling water for the absorber 1, increases, so the solution concentration in the absorber 1 increases. becomes higher, the solution concentration 21 in the low-temperature regenerator 3 also rises, and the saturation temperature rises, so no significant improvement can be expected.

Therefore, even if an absorption heat pump is made to have dual effect with high thermal efficiency, the hot water outlet temperature cannot be raised, and the amount of heat available for process heating is reduced. The drawback was that the amount of heat pumped up from the water was also reduced. On the contrary, single-effect systems can raise the hot water outlet temperature, which increases the amount of heat that can be handled and pumps up more heat from the heat source water, resulting in a higher energy-saving effect.

A related example of this type is JP-A-54-79859.

An object of the present invention is to provide a dual-effect absorption heat pump that can maintain high-temperature regenerator pressure below atmospheric pressure and obtain hot water at a higher temperature than before in a dual-effect absorption heat pump cycle. be.

In order to obtain hot water as high as possible at the lowest possible high-temperature regenerator pressure in a dual-effect absorption heat pump cycle, the solution temperature in the low-temperature regenerator that exchanges heat with the refrigerant vapor generated in the high-temperature regenerator must not be raised too much. This leads to not increasing the solution concentration at the absorber outlet. Furthermore, in order to condense the low-temperature refrigerant vapor generated in the low-temperature regenerator in the condenser, it is necessary to pass hot water as low as possible through the condenser heat transfer tube. First, in order to pass the latter hot water with a temperature as low as possible through the condenser heat transfer tube, the hot water is passed in the order from the condenser to the absorber, and in order to avoid increasing the solution concentration at the outlet of the former absorber, the evaporator and absorber are The solution was run in such a way that, considering only the absorption solution cycle, there were two single-effect cycles, each with a low-temperature regenerator or a high-temperature regenerator. The temperature of the low-temperature regenerator can be lowered by sending a lower-concentration, lower-temperature solution, which has been cooled with hot water at the absorber inlet to absorb the refrigerant, to the low-temperature regenerator. can be satisfied. Furthermore, by dividing the evaporator and absorber into two to form two independent absorption solution cycles, the concentration on the low temperature regenerator side can be adjusted independently of the high temperature regenerator side cycle by adjusting the flow rate. It became possible to adjust the width.

An embodiment of the present invention will be described below with reference to FIG.

Among the symbols shown in FIG. 2, the same symbols as those shown in FIG. 1 indicate the same parts.

In FIG. 2, 1a and 1b are absorbers divided by a partition wall 22, and these absorbers 1a (first absorber) and 1b (second absorber) are tubes 14a and 1b.
Each of them has a built-in group 4b. 2a and 2b are evaporators divided by a partition wall 22, and each of the evaporators 2a (first evaporator) and 2b (second evaporator) incorporate tube groups 15a and 15b, respectively.
6a is a pump that sends the absorbed liquid from the absorber 1a to the low-temperature regenerator 3 via a conduit 7a and a heat exchanger 8a. 6b is a pump that sends the absorbed liquid from the absorber 1b to the high-temperature regenerator 5 via the conduit 7b and the heat exchanger 8b. High temperature regenerator 5
A tube group 18 is built in, and a heat source 23 such as steam is supplied to the tubes. 19 is refrigerant vapor generated in the high temperature regenerator 5;
The liquid flows into the tube group 16 inside, heats the solution 21, condenses into liquid, and flows into the condenser 4. 2
0 is a conduit that leads the refrigerant liquid from the condenser to the evaporators 2a and 2b. 10 is a tube group 15 of the evaporators 2a and 2b
A pump that sprays refrigerant onto a and 15b to promote evaporation. 8a is a heat exchanger for the absorption liquid sent from the absorber 1a to the low-temperature regenerator 3 and the absorption liquid returned from the low-temperature regenerator 3 to the absorber 1a. 8b is a heat exchanger for the absorption liquid sent from the absorber 1b to the high-temperature regenerator 5 and the absorption liquid returned from the high-temperature regenerator to the absorber 1b. A conduit 20 guides the refrigerant condensed in the condenser 4 to the evaporators 2a and 2b. 12 is hot water supplied to the tube group 17 of the condenser 4 and the tube groups 14a and 14b of the absorbers 1a and 1b;
As shown in the figure, the water flows from the condenser 4 to the absorbers 1a and 1b in this order. 13 is low temperature heat source water supplied to the tube groups 15a and 15b of the evaporators 2a and 2b;
It is distributed in the order of a and 15b.

In this embodiment, as described above, the absorber 1a and the evaporator 2a provided on both sides of the partition wall 22, and the absorber 1a are provided on both sides of the partition wall 22.
Each set of absorber and evaporator 2b independently performs absorption and evaporation functions, and each set of absorber and evaporator (1a vs. 2a and 1b vs. 2b) performs absorption and evaporation actions independently. ) have their own absorption and evaporation temperatures. In other words, on the left side, the evaporator 2a on the side where the low-temperature heat source water is higher and the absorber 1a on the side where the hot water temperature is lower work together to evaporate and absorb the final water that flows out from the tube group 14b of the absorber 1b. Even if the hot water temperature is high, the absorber 1a
The absorption liquid becomes sufficiently dilute. Therefore, since the concentration of the absorption liquid flowing into the low-temperature regenerator 3 is low, the concentration of the absorption liquid 21 in the low-temperature regenerator also decreases, even though the temperature of the hot water flowing into the tube group 17 of the condenser 4 becomes higher than before. The saturation temperature of the absorption liquid 21 does not rise, and the refrigerant vapor 1 generated in the high temperature regenerator 5 in the tube group 16
The condensation temperature of the high-temperature regenerator 5 does not increase, and as a result, the pressure of the high-temperature regenerator 5 can be prevented from increasing. On the other hand, on the right side, the evaporator 2b on the side where the low-temperature heat source water is low and the absorber 1b on the side where the hot water temperature is high work together to perform evaporation and absorption, so the concentration of the absorbed liquid in the absorber 1b increases, but this absorption The absorbed liquid in the vessel 1b is sent to the high-temperature regenerator 5, and since the temperature level of the heating source 23 flowing into the tube group 18 built in the high-temperature regenerator 5 is usually sufficiently high, it is heated and concentrated.

The above absorption solution cycle will be further explained using the Düring diagram shown in FIG. A is the evaporator 2a
b represents the evaporation temperature of the evaporator 2b, and c represents the condensation temperature of the condenser 4. a represents the absorption liquid temperature of the absorber 1a, b represents the absorption liquid temperature of the absorber 1b, and c represents the absorption liquid outlet temperature of the low temperature regenerator 3. Further, the concentration of the absorbent increases as it goes to the right side in the direction of the arrow in the figure. As shown in Fig. 3, the absorbent liquid in the absorber 1a is indicated by point A from the evaporation temperature a and the absorbent liquid temperature a, and similarly, it appears to be much wider than the point B which indicates the absorbent liquid in the absorber 1b. You can see that it is getting thinner. In order to send the thin absorbent liquid in the absorber 1a to the low temperature regenerator 3, even if the hot water temperature in the condenser 4 becomes high and the condensation temperature reaches c, the absorbent liquid temperature remains at c and is built into the low temperature regenerator. The condensation temperature of the refrigerant vapor generated in the high-temperature regenerator, which condenses in the tube group 16, also remains at c', which is higher by ΔT required for heat transfer. Therefore, even if the temperature at the entrance and exit of the hot water 12 becomes high,
The rate of increase in temperature c′ is small, that is, high temperature regenerator 5
The range in which the pressure of does not exceed atmospheric pressure (temperature of c′ 100℃
(below) and the hot water temperature increases. Also, the third
As can be seen from the figure, if the concentration width of the absorption liquid cycle formed by the absorber 1a and the low-temperature regenerator 3 is reduced, points A and B will approach each other, and the temperature at c will decrease, making it possible to handle even higher hot water temperatures. I understand that. Note that the absorbed liquid in the absorber 1b can be represented by point C, and the absorbed liquid in the high-temperature regenerator 5 can be represented by point D, but if a heating source 23 whose temperature is higher than D is selected, this cycle is established. That's what I do. Depending on the hot water temperature conditions at both points C and D, the concentration of the absorption liquid will be higher than in a normal dual-effect absorption type, but absorber 1
The temperature inside b is sufficiently high, and the danger to the crystals is rather small.

FIG. 4 shows another embodiment of the present invention, in which low-temperature heat source water is supplied to a tube group 15b built in the evaporator 2b.
After flowing into the tube group 15a built in the evaporator 2a, it flows out in the direction of the arrow. The rest is the same as the embodiment shown in FIG. 2, so a description thereof will be omitted. In this embodiment, the evaporation temperature of the evaporator 2b corresponding to the absorber 1b disposed on the outlet side of the hot water 12 is high, and the concentration of the absorption liquid in the absorber 1b is low.
Since the temperature of the absorption liquid in the high temperature regenerator 5 is lowered, there is an advantage that the temperature of the heating source 23 is lowered.

As explained above, according to the present invention, the hot water temperature can be raised to a high temperature using the dual-effect absorption type with high absorption solution cycle efficiency, so the amount of heat that can be heated by the hot water leaving the dual-effect absorption type heat pump increases. death,
The amount of heat pumped from low-temperature heat source water (heat that is normally discarded to the outside world as waste hot water) is increased by 1.5 to 2 times due to its cycle efficiency compared to single-effect systems, making it possible to achieve true energy savings.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a conventional dual-effect absorption heat pump, Figs. 2 and 4 are system diagrams showing an embodiment of the dual-effect absorption heat pump of the present invention, and Fig. 3 is a system diagram of a conventional dual-effect absorption heat pump. It is a Duehring diagram showing an absorption solution cycle. 1a, 1b...absorption liquid, 2a, 2b...evaporator, 3...low temperature regenerator, 4...condenser, 5...high temperature regenerator, 12...hot water, 13...low temperature heat source water.

Claims (1)

[Claims] 1. High temperature regenerator, low temperature regenerator, condenser, evaporator,
In a dual-effect absorption heat pump in which an absorber, a heat exchanger, and a pump are operatively connected, the evaporator and absorber are connected to a first evaporator and a second evaporator, respectively, through a partition wall. , and a first absorber,
This divided first absorber is divided into a second absorber.
The evaporator, the second evaporator, the first absorber, and the second absorber perform evaporation and absorption independently, and hot water is passed in series to the first absorber and the second absorber. the first absorber and the low temperature regenerator form an independent first absorption solution cycle;
The absorber and the high-temperature regenerator form an independent second absorption solution cycle, and hot water is passed through the condenser, the first absorber, and the second absorber in this order. Dual effect absorption heat pump. 2. The dual-effect absorption heat pump according to claim 1, wherein the heat source water is passed through the first evaporator and the second evaporator in this order. 3. The dual-effect absorption heat pump according to claim 1, wherein the heat source water is passed through the second evaporator and then the first evaporator in this order.