JPS5849780B2 - Absorption heat pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an absorption type heat pump, specifically a basic type second type heat pump.
This invention relates to a second type absorption heat pump in which a seed heat pump is operated in two stages to operate a low-temperature and high-temperature heat pump cycle, thereby obtaining hot water at a higher temperature than that of the basic type heat pump.

Absorption heat pumps are classified into type 1 heat pumps and type 2 heat pumps, of which the absorption temperature is higher than the generation temperature, and the evaporation temperature of the refrigerant is higher than the condensation temperature. This is a device that evaporates a refrigerant using heat pumped up from a low-temperature heat source such as heated waste water, and obtains high-temperature hot water using the absorbed heat generated when the refrigerant vapor is absorbed into an absorption liquid.

The basic type of the second type absorption heat pump is, for example, as shown in FIG.
A generator 5 and a condenser 6 are housed in the lower shell 4. A heat exchanger 7 is provided between the generator 5 and the absorber 3 to improve efficiency, and an absorption liquid pump 8 and a refrigerant pump are installed. 9 is attached, and a refrigerant recirculation pump 13 for recirculating the liquefied refrigerant in the evaporator 2 and its connecting piping are attached. Cooling water 11 is used as an endothermic heat source for each of the vessels 6, and hot water 12 is obtained from the absorber 3.

For example, water and an aqueous lithium bromide solution are used as the refrigerant absorption liquid.

The operation cycle of the second type heat pump is as follows.

That is, the heated waste water 10 serving as a heat source is guided to the evaporator 2, and the heat of the heated waste water is given to the refrigerant.

The refrigerant vapor evaporated in the evaporator 2 by this heat is absorbed by an absorption liquid in the absorber 3.

The amount of heat generated in this absorption process heats the water passing through the absorber 3 so that hot water 12 is obtained.

The absorption liquid that has absorbed refrigerant vapor and is diluted is sent to the generator 5 via the heat exchanger 7.

The absorbed liquid is heated in the generator 5 by heated waste water 10 serving as a heat source, boils and is concentrated.

The concentrated absorption liquid is transferred to a heat exchanger 7 by an absorption liquid pump 8.
After heat exchange with the hot diluted liquid from the absorber 3 through the absorber 3
Enter and repeat absorption.

Refrigerant vapor generated in the generator 5 is led to the condenser 6, where it is cooled and condensed by the cooling water 11.

The liquefied refrigerant is sent to the evaporator 2 by a refrigerant pump 9.

The liquefied refrigerant in the evaporator 2 is recirculated by a refrigerant recirculation pump 13.

In this way, by utilizing the heat drop between the heated wastewater and the cooling water, the absorber heats the hot water even higher and sends it out.

In the basic type of absorption heat pump, for example, the temperature of the heated waste water 10 is 60°C and the temperature of the cooling water 11 is 15°C.
When , the hot water 12 obtained from the absorber 3 is approximately 80°C.
~90°C, but in order to make the hot water 12 obtained from the absorber 3 higher temperature by setting the temperature conditions of the heated wastewater and cooling water as described above, the above-mentioned basic type absorption heat pump is replaced with a second one. As shown in the figure, install two units in a row and place one on the low temperature side 20.
, this becomes possible by setting the other side to the high temperature side 21.

In FIG. 2, the same reference numerals are used for parts common to those in FIG. 1, and the numbers are suffixed with a for the low temperature side and b for the high temperature side.

In the low-temperature side heat pump 20, the temperature of the heated waste water 10 is 60°C, the temperature of the cooling water 11 is 15°C, and the obtained hot water 12 is
is 80°C, but in the high temperature side heat pump 21, the 80°C hot water 12 from the low temperature side is guided to the evaporator 2b and the generator 5b, and if the temperature of the cooling water 11 is 15°C, the hot water 12 from the absorber 3b is A high temperature water or steam 22 of 100°C to 120″C is obtained.

However, although it is possible to install two basic type absorption heat pumps in series as described above, there is a problem in that the machines become large and the cost naturally increases.

The present invention aims to provide a compact absorption heat pump having the same performance as that of two absorption heat pumps of the aforementioned basic type connected in series.

The absorption type heat pump according to the present invention has a low-temperature evaporator and a low-temperature absorber housed in one upper shell, and a high-temperature evaporator and a high-temperature absorber housed in the other upper shell. It is similar to a heat pump, but the lower body contains a low-temperature generator and a high-temperature generator, as well as a condenser for both low and high temperatures. waste water, cooling water to cool the condenser, liquid refrigerant or a mixture of refrigerant and absorption liquid evaporated in a high temperature evaporator and heated by a low temperature absorber to transfer heat to a high temperature generator. Two heat pump cycles, one on the low-temperature side and one on the high-temperature side, are operated to obtain high-temperature water from the high-temperature absorber using liquids (hereinafter referred to as mixed heat medium).

Embodiments of the absorption heat pump according to the present invention will be described with reference to the drawings.

In Figure 3, the same reference numbers are used for the same parts as in Figures 1 and 2.
is attached.

In FIG. 3, the upper shell is divided into two parts, a low-temperature side 20 and a high-temperature side 21, and a low-temperature evaporator 2a,
A low-temperature absorber 3a is provided with a high-temperature evaporator 2 in the upper body 1b on the high-temperature side.
b, a high temperature absorber 3b is housed, and one lower body 23 houses a low temperature generator 24, a high temperature generator 25, and a condenser 26 for both low and high temperatures.

The external connection piping is configured such that heated waste water 10 flows in and out as a heating heat source for the low-temperature evaporator 2a and as a driving heat source for the low-temperature generator 24, and cooling water 11 flows in and out as an endothermic heat source for the condenser 26. and high temperature water or steam2
2 is taken out from the high-temperature absorber 3b, hot water flows in and out.

On the other hand, the liquid refrigerant or the mixture of refrigerant and absorption liquid in the high-temperature evaporator 2b, that is, the mixed heat medium, first passes through the tube in the high-temperature generator 25 by the heat medium pump 27, and then passes through the pipe in the low-temperature absorber 3.
A flash evaporator is used as the high-temperature evaporator 2b that is guided into the high-temperature evaporator 2b through the tube inside a.

Also, is there a heat exchanger between the low temperature generator 24 and the low temperature absorber 3a and between the high temperature generator 25 and the high temperature absorber 3b to improve efficiency? a 7b, absorption liquid pumps 8a and 8b are attached to the low-temperature side and high-temperature side, a refrigerant pump 9 is attached to the condenser 26, and a high-temperature evaporator 2
A heat medium pump 27 is attached to b, and a refrigerant recirculation pump 13 and its connecting piping are attached for forcibly dropping the liquefied refrigerant in the low-temperature evaporator 2a onto the heat transfer tubes.

It goes without saying that the refrigerant pump 9 and the refrigerant recirculation pump 13 have a pump protection device such as a liquid level relay to prevent pump cavitation or the like.

The heat pump cycle of this absorption heat pump will be explained.

The refrigerant vapor generated in the lower shell 23 is condensed in the condenser 26 to become a liquid refrigerant, and the refrigerant pump 9 sends the liquid refrigerant to the low-temperature evaporator 2a and the high-temperature evaporator 2b.

Next, the absorption liquid is divided into a low temperature cycle and a high temperature cycle. In the low temperature cycle, the absorption liquid is transferred to the low temperature generator 24.
The concentrated liquid is heated by the heated waste water 10 and sent to the low-temperature absorber 3a by the absorbent pump 8a, where it absorbs the refrigerant evaporated by the low-temperature evaporator 2a, and the absorbed heat flows through the pipe. Tell the fluid.

Next, in the high-temperature cycle, the absorption liquid is heated in the high-temperature generator 25 by the mixed heating medium from the high-temperature evaporator 2b, becomes a concentrated liquid, and is guided to the high-temperature absorber 3b by the absorption liquid pump 8b, where the refrigerant coming from the high-temperature evaporator 2b The absorbed heat generated at this time heats the hot water 22 flowing inside the high temperature absorber 3b.

The absorption liquid, which has become thinner by absorbing the refrigerant that heated the hot water, returns to the high temperature generator 25 and is heated again to become a concentrated liquid, and the same cycle is repeated.

A characteristic feature of this cycle is the circulation cycle of the mixed heat medium.

The mixed heat medium that has exited the high-temperature evaporator 2b is pumped by the heat-medium pump 27 and sent into the tube of the high-temperature generator 25, where it gives heat to the absorption liquid flowing down outside the tube, and the temperature increases. The temperature decreases and is sent to the low-temperature absorber 3a.

In the low-temperature absorber 3a, contrary to the high-temperature generator 25, it is heated by the absorption liquid flowing down outside the tube.

This heated mixed heat medium is led to the high-temperature evaporator 2b, and is sprayed into the container by a spray nozzle installed in the high-temperature evaporator, flash evaporates, and becomes refrigerant vapor, and the liquid cools itself by self-evaporation. In the above-described embodiment, the circulation cycle of this mixed heat medium is as follows: high-temperature vapor heat medium pump high-temperature generation low-temperature absorption Although we have shown examples of how to flow this mixed heat medium, there are other ways to flow this mixed heat medium.
For example, a system in which high temperature evaporation heat medium low temperature absorption high temperature generation high temperature evaporator 2b pump 27 collector 3a generator b generator 2b flows in series, high temperature evaporation heat medium low temperature absorption high temperature evaporator 2b pump 27 collector 3 Generator 2b high-temperature generator, part of the system flows in parallel, high-temperature vapor heat medium pump low-temperature absorption high-temperature generation high-temperature evaporator 2b pump 2 collector 3a generator 25 generator 2b low-temperature evaporator part 7,
Various methods are conceivable, such as a method in which part of the power flows in parallel and a part of the power is bypassed, as shown in A7, 7 and Generator 2a.

FIG. 4 depicts the operating cycle of the absorption heat pump according to the present invention on a Dühring diagram.

In the figure, A is the circulation cycle of the absorption liquid on the low temperature side, B is the circulation cycle of the absorption liquid on the high temperature side, C is the circulation cycle of the refrigerant,
is the temperature at which the refrigerant vapor condenses in the condenser 26, t
2 is the temperature at which the absorption liquid completes boiling concentration in the low temperature generator 24, t3 is the temperature at which the refrigerant evaporates in the low temperature evaporator 2a, and t4 is the temperature at the point at which the absorption liquid completes boiling concentration in the high temperature generator 25. , t5 is the temperature at which the refrigerant evaporates in the high-temperature evaporator 2b, t6 is the temperature at the point at which absorption of the absorption liquid is completed in the low-temperature absorber 3a,
t7 is the temperature at the point where the absorption liquid has completed absorption in the high-temperature absorber 3b, P is the pressure in the upper shell 1a on the low temperature side, PB is the pressure in the upper shell 1b on the high temperature side, and PC is the pressure in the lower shell 23. Yes, in low-temperature absorption liquid cycle A, a-hb is absorption in the absorber, b-4-c
is the state change on the dilute solution side during heat exchange between the dilute solution and the concentrated solution, (-d is boiling concentration in the generator, d-4-a is the heat exchange 1) -a- (the state on the concentrated solution side corresponding to It shows change.

Hot absorbent cycle B operates similarly to cycle A.

In this heat pump, the evaporation temperature and heating temperature are the same, and only the heat output from the absorber can be used as hot water.

Therefore, the coefficient of performance (COP) is as follows: Qo: Heat received by the low temperature generator QE: Heat received by the low temperature evaporator QA: Cooling heat amount of the high temperature absorber Qc: Cooling heat amount of the condenser.

Since the absorption heat pump according to the present invention has four barrels as shown in FIG. 2, it is reduced to three as shown in FIG. It is possible to obtain hot water at a higher temperature than the basic type of absorption heat pump.

[Brief explanation of drawings]

Figure 1 is a diagrammatic explanatory diagram of the basic type 2 heat pump, and Figure 2 is the basic type 2 type heat pump shown in Figure 1.
FIG. 3 is a diagrammatic explanatory diagram of a heat pump connected in stages, FIG. 3 is a diagrammatic explanatory diagram of an embodiment of an absorption heat pump according to the present invention, and FIG. 4 is an overview of a Dühring diagram of an absorption heat pump according to the present invention. . A... Circulation cycle of the absorption liquid on the low temperature side, B...
...High temperature side absorption liquid circulation cycle, C...Refrigerant cycle, t...Temperature, P...Pressure, 1... Upper shell, 2... Evaporator, 3.
...Absorber, 4...Lower body, 5...
Generator, 6... Condenser, 7... Heat exchanger, 8... Absorption liquid pump, 9... Refrigerant pump, 10...・・Hot waste water, 11・・・Cooling water, 12・・・・Hot water, 13・・・・Refrigerant recirculation pump, 20・・・・Low temperature side heat pump, 2
1...High temperature side heat pump, 22...
High-temperature water and steam, 23...Lower body, 24...
... Low temperature generator, 25 ... High temperature generator, 26
...Condenser, 27... Heat medium pump.

Claims (1)

[Claims] 1 A low-temperature evaporator and a low-temperature absorber are housed in one upper shell, a high-temperature evaporator and a high-temperature absorber are housed in the other upper shell,
A low-temperature generator and a high-temperature generator are housed in one lower body, and a condenser for both low and high temperatures is housed in one lower body, and heated waste water is used to heat the low-temperature evaporator and the low-temperature generator, and the condenser is cooled. The cooling water is evaporated in the high-temperature evaporator and a refrigerant heated by the low-temperature absorber or a mixture of a refrigerant and an absorption liquid is used to transfer heat to the high-temperature generator, and the low-temperature side is heated. and an absorption heat pump characterized in that two heat pump cycles on the high temperature side are activated to obtain high temperature water from the high temperature absorber.