JPS5944555A - Absorption type heat pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (a) Field of the Invention The present invention relates to an absorption type heat pump that uses a low temperature fluid as a heat source to obtain a high temperature fluid by using a closed circulation cycle of an absorption liquid and a refrigerant. (b) Conventional absorption heat pumps are classified into type 1 heat pumps and type 2 heat pumps, of which the absorption temperature is higher than the generated humidity, and the evaporation temperature of the refrigerant is higher. It is generated when the refrigerant is evaporated by the heat drawn from a low-temperature heat source such as heated waste water, and this refrigerant vapor is absorbed into the liquid. This is a device that obtains high-temperature hot water by absorbing heat.

The basic helicopter type of the second type absorption heat pump (for example, as shown in Fig. 1, evaporation e% 2 is
- and an absorber 3 are housed in the lower shell 4, a generator 5 and a condenser 6 are housed in the lower shell 4, and a heat exchanger 7 is provided between the generator 5 and the absorber 30 to improve efficiency; A liquid pump 8 and a refrigerant pump 9 are attached, and a refrigerant recirculation pump 13 for recirculating the liquefied refrigerant in the evaporator 2, its connections, and piping are attached, and is used as a heating heat source for the evaporator 2 and for driving the generator 5. The heated waste water 10 is used as a heat source, the cooling water 11 is used as an endothermic heat source for the condenser 6, and the absorber 3 also receives high-temperature water or steam 12. For example, water and an aqueous lithium bromide solution are used as the refrigerant/absorbing liquid.

In the 11J cycle made by the second scale Heat Bomb, heated waste water 10 serving as a heat source is led to the evaporator 2, and the heat of the heated waste water is given to the refrigerant. The refrigerant vapor is absorbed by the absorption liquid in the absorber 3. The heat generated in this absorption process heats the water passing through the absorber 3, resulting in high temperature water or vapor 12. The diluted absorption liquid is transferred to heat exchanger 7.
The signal is sent to the generator 5 via the . 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 passes through the heat exchanger 7 by the absorption liquid pump 8, exchanges heat with the Takafuchi diluted solution in the absorber 3, and then enters the absorber 3 to repeat absorption. Refrigerant vapor generated in the generator 5 is led to an injection condenser 6, where it is cooled and condensed by 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 13Vc. In this way, by utilizing the heat drop between the heated waste water and the cooling water, the absorber heats the hot water to a higher temperature and sends it out. (c) Problems with the conventional technology These conventional absorption types In a heat pump, for example, the temperature of heated waste water 10 is 60°C and the temperature of cooling water 11 is 1
At 5℃, absorber 3 may yield 1 ↓ (high temperature water 1
2 is approximately 80°C to 90°C. In order to operate the heat pump cycle mentioned above, it is necessary to prevent the absorption liquid from crystallizing. Conventionally, the method generally used to prevent the crystallization of the absorption liquid is to A thermostat is inserted to shut down the equipment when the temperature of the concentrated solution rises. However, this method can prevent crystallization of the absorbed liquid when the heat source temperature remains unchanged and the condensation pressure is constant, but as the heat source temperature changes, the condensation pressure also changes. There was a problem that the method of detecting a single addition of a concentrated solution at only one point was inadequate.

B) Purpose of the Invention In order to solve the above-mentioned problems, the present invention provides a heat pump of the above-mentioned basic type, in which a temperature measuring resistor or the like is installed in the condenser and generator, respectively, in order to detect the temperature difference between the refrigerant liquid and the concentrated solution. A temperature detector is inserted, and a solenoid valve is interposed in the middle of the piping connecting the evaporator and the generator, and when the temperature difference exceeds a predetermined set value, the solenoid valve is activated and the inside of the evaporator is activated. refrigerant is mixed into the absorption liquid in the generator to keep the concentration of the absorption liquid low, thereby preventing crystallization of the absorption liquid, and achieving t4
The present invention aims to provide an absorption heat pump that can be operated within a concentration range.

(e) Main points of the invention In an absorption heat pump that uses a heat source at a low temperature level to obtain a fluid at a high temperature level, the temperature of the refrigerant liquid in the condenser and the temperature of the concentrated solution in the generator are detected. When the difference in liquid temperature exceeds a preset value of 1-1'1', the refrigerant in the evaporator is mixed with the absorbent in the generator to reduce the concentration of the absorbent. be.

(f) Embodiment of the Invention In Fig. 2 showing the operating cycle of an absorption heat pump, A is a standard absorption liquid circulation cycle, B is a refrigerant, and tl
is the temperature at which the refrigerant vapor condenses in the condenser, t2
is the temperature of the absorption liquid that completes boiling concentration in the generator and exits the generator, t3 is the temperature at which the refrigerant evaporates in the evaporator,
t4 is the imaginary temperature at which the absorption liquid leaves the absorber after completing absorption;
PA is the pressure inside the upper body, P and l are the pressures inside the lower body,
In absorption liquid cycle A, 2-+ l) is absorption in absorber 3, l) -+ ( is state change on the dilute solution side in heat exchange between dilute solution and concentrated solution, C-+ d is absorption in generator 5
Boiling concentration, d→a, indicates a state change on the concentrated solution side corresponding to heat exchange b-+C, and the heat output from the absorber is used to heat hot water.

The cycle on this data IJ diagram changes if the temperature and pressure conditions of the absorption heat pump change, but for example, under pressure P,,'-4,5γmI-Tg,
Absorption liquid temperature T, -36.5℃, refrigerant temperature IgTc =O
The concentration at the crystal critical point at °C is 62% and the pressure is P. -5
If the concentration at the crystal critical point is 66% when the absorption liquid temperature T = 95°C and the refrigerant temperature T = 38°C under 0 Hg, then the area below the dotted line connecting these two points is This is the area where operation as an absorption heat pump cannot be performed or where operation should be avoided.

On the other hand, if the boundary (dotted line in FIG. 2) indicating this region is assumed to be a straight line, this boundary line can be determined as the -dimensional number between the temperature Tc of the refrigerant and the temperature TQ of the absorbing liquid. Assuming that the values of these temperatures 'r, , TC, To, and 'r are as described above (therefore, the relationship shown by the dotted line in Fig. 2),
Tc and T. Which relation, Tc= aT, + b
(However, a, b are constants), then this - following equation has Tc, T
(, To, by substituting the values of T2 and eliminating a and b, the relational expression T, = 1.54Tc + 36.51 is obtained.

Therefore, if the operation is performed under the conditions of T, (1,54To+36.51), crystals of the absorption liquid can be avoided, and T
,-T. Diagram showing the relationship between tobacco.

That is, Tl, = 1.54Tc + 36.51 straight l
¥! The upper left region with i as the border is the crystal region, and the lower right E is the operating region.

Note that the above-mentioned first-order discriminant can also be used as a discriminant that takes into account a second-order or higher-order term to match the actual data depending on the type of absorption and refrigerant liquid. T so that you can drive inside. and T
Crystals can be prevented by detecting the temperature difference c and activating the solenoid valve for preventing crystals.

The explanation will be given below with reference to an explanatory diagram of an absorption heat pump showing an embodiment of the present invention. In FIG. 4, the same reference numerals are used for the same parts as in FIG. 1. In FIG. 4, an evaporator 2 and an absorber 3 are housed in an upper shell 1, and a generator 5 and a condenser 6 are housed in an upper shell 4. The external connection piping is configured such that heated waste water 10 flows in and out as a heating heat source for the evaporator 2 and as a driving heat source for the generator 5, and cooling water 11 flows in and out as an endothermic heat source for the condenser 6. High temperature water or steam 12
Hot water is made to flow in and out so as to be taken out from the absorber 3.

A heat exchanger 7 for improving efficiency is provided between the generator 5 and the absorber 3, an absorption liquid pump 8 is attached to the generator 5, a refrigerant pump 9 is attached to the condenser 6, and an evaporator pump 9 is attached to the condenser 6. 2
In order to forcibly drip the liquefied refrigerant inside onto the heat transfer tubes, a refrigerant retiQ ring pump 13 and its connecting piping are provided. 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.

In order to detect the temperature of the concentrated solution in the generator (5), a temperature sensor 05) such as a resistance temperature detector for preventing crystallization is inserted into the generator (5), and the temperature of the refrigerant liquid in the condenser (6) is In order to detect the temperature, a temperature detector <16+, such as a resistance temperature detector for crystallization prevention, is inserted in the condenser (6), and A crystalline anti-TLZ output (17) is interposed in the middle, and the temperature difference between the temperature of the concentrated solution in the generator (5) and the temperature of the refrigerant liquid in the condenser (6) is a predetermined set value. When the temperature exceeds this point, a solenoid valve (17) is activated to open the flow path.

The heat pump cycle of this absorption heat pump will be explained. The refrigerant vapor generated in the lower shell (4) is transferred to the condenser (
6), it is condensed into liquid refrigerant, and the refrigerant is pumped into the refrigerant pump (9).
) to the evaporator (2). Next, the absorption liquid is heated in the generator (5) by heated wastewater 00), becomes a concentrated liquid, and is sent to the absorber (3) by the absorption liquid pump (8).

The absorber (3) absorbs the refrigerant gas flowing in from the evaporator (2), and the absorption heat generated at this time heats the hot water (1) flowing inside the absorber (3). The descending absorption liquid returns to the generator (5) and is heated again, and the above-mentioned cycle is repeated to continue the heating operation.

During this cycle, the temperatures of the concentrated solution in the generator (5) and the refrigerant liquid in the condenser (6) detected by the two anti-crystallization resistance thermometers 05) and (16) The difference is a predetermined temperature IW difference setting value, that is, T shown in FIG.
, -T, , when the value obtained from the relationship of
2) The refrigerant in the generator (5) is mixed with the absorption liquid in the generator (5), so that the concentration of the absorption liquid is kept low, and crystallization of the absorption liquid is prevented.

(G) Effects of the Invention As described above, the absorption heat pump of the present invention is different from the general absorption heat pump in that the temperature difference between the refrigerant liquid in the condenser and the concentrated solution in the generator has a predetermined set value. By adding a mechanism that mixes the refrigerant in the evaporator with the absorption liquid in the generator to keep the absorption liquid concentration low, it is possible to prevent the absorption liquid from crystallizing and to operate the absorption heat pump in a high temperature range. Efficient <;'A [It is something that can be converted.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the basic configuration of an absorption heat pump.
Fig. 2 is a Dueling diagram explaining the operation of the heat pump shown in Fig. 1, Fig. 3 is a TC-To diagram showing an example of the boundary line between the crystal region and the operating region, and Fig. 4 is the absorption heat pump according to the present invention. It is an explanatory view showing an example. 1-upper shell, 2-evaporator, 3-absorber, 4-lower shell,
5 - Generator, 6 - Condenser, 15.16 - Temperature detector, 17 - Solenoid valve. Every 1 figure temperature L ('C) 3rd figure Tc (0C)

Claims (1)

[Claims] (1) It has an evaporator and an absorber housed in the upper shell, and a generator and a condenser housed in the lower shell, and hot wastewater is condensed to heat these evaporators and generators. In an absorption heat pump in which the heat pump cycle is operated using cooling water to cool the reactor, and high-temperature water or steam can be taken out from the absorber, the temperature of the refrigerant liquid in the condenser and the concentrated solution in the generator is controlled. In order to detect the refrigerant in the condenser, a temperature detector such as a resistance temperature detector is attached to each of the condenser and generator, and a solenoid valve is inserted in the middle of the piping connecting the evaporator and generator. When the temperature difference between the liquid and the concentrated solution in the generator exceeds a predetermined set value, the solenoid valve is activated to mix the refrigerant in the evaporator into the absorbent in the generator to suppress the concentration of the absorbed liquid. An absorption heat pump characterized in that it can be operated in a high temperature range while preventing crystallization of an absorption liquid.