JP3103225B2 - Absorption heat pump using low-temperature heat source - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption heat pump using a low-temperature heat source that uses heat of river water or sewage as a driving heat source.

[0002]

2. Description of the Related Art A conventional heat pump utilizing river water or sewage treatment water as a heat source water obtains warm water for heating (40 ° C. to 45 ° C.) by setting up a single-effect cycle of direct fire or steam drive. .

[0003]

However, in the case of using two levels of exhaust heat (low-temperature water 65 ° C. to 75 ° C., steam) such as fuel cell exhaust heat as a heat source for driving a heat pump, a conventional single-effect cycle is used. Since it is impossible to use low-temperature water waste heat with high efficiency, the temperature is raised in a single-effect cycle using only steam, and the low-temperature water waste heat is recovered using a heat exchanger for heating. There is a drawback that hot water is obtained, which results in a large consumption of steam.

[0004] It is an object of the present invention to reduce the consumption of steam used to obtain hot water for heating in an absorption heat pump utilizing a low-temperature heat source.

[0005]

The structure of an absorption heat pump utilizing a low-temperature heat source according to the present invention is as follows.

[0006] Evaporator, first absorber, first generator, first heat exchanger, second absorber, second generator, third generator, condenser, second heat exchanger, third heat exchange A heat source water line passed through the evaporator, a hot water extraction line circulating through the condenser from the first absorber through the second absorber, a low temperature water extraction line circulating through the first generator, A first bypass line for cooling switching, which branches off a first diluted solution line from the first absorber to the first generator and connects to a second diluted solution line from the second absorber to the second generator; The second concentrated solution line from the third generator to the second absorber is branched and the second concentrated solution line is branched from the first generator to the first
The heating cycle includes a second bypass line for switching cooling connected to the first concentrated solution line leading to the absorber, and in the heating cycle, heat is drawn from the low-temperature heat source in the evaporator and the evaporated refrigerant vapor is converted into the absorbing solution in the first absorber. Absorbed, the dilute solution in the first absorber is passed through the first heat exchanger by the solution pump, heated by the low-temperature water led to the first generator and separated into refrigerant vapor and a concentrated solution. The separated concentrated solution is passed through a first heat exchanger and sent to a first absorber,
The refrigerant vapor is again absorbed and circulated between the first absorber and the first generator, and the refrigerant vapor generated in the first generator is absorbed in the absorption solution in the second absorber, and the diluted solution in the second absorber is absorbed. Was led to the second generator through the second heat exchanger and the third heat exchanger by the solution pump, and was heated by steam (high-temperature heat source) to be separated into an intermediate-concentration solution and a refrigerant vapor, and separated in the second generator. The intermediate-concentration solution is led to the third generator via the third heat exchanger, and the refrigerant vapor generated in the second generator causes
It is further heated to separate it into a concentrated solution and refrigerant vapor, and the concentrated solution separated in the third generator is sent to the second absorber via the second heat exchanger, and the refrigerant vapor generated from the first generator is absorbed again. Then, the absorbing solution is circulated in the order of the second absorber, the second generator, and the third generator, and the refrigerant vapor generated in the second generator is guided to the third generator, and the intermediate solution is heated and concentrated. And
After the condensation, the refrigerant is led to the condenser 8, the refrigerant vapor generated in the third generator is led to the condenser, and latent water is given to the cooling water (here, the heating water for heating) to be condensed. Sends, pumps out the heat of the low-temperature heat source, evaporates, and flows the hot water for heating through the hot water take-out line in the order of the first absorber, the second absorber, and the condenser, and in the first absorber, the second absorber In the cooling cycle, the refrigerant vapor generated by removing heat from the cooling water in the evaporator receives the heat of absorption and the heat of condensation in the condenser. In the first absorber, the diluted solution in the first absorber is absorbed into the absorbing solution, guided to the second generator through the first heat exchanger and the third heat exchanger by the solution pump, and heated by steam to form an intermediate concentration solution. Separated into refrigerant vapor and the intermediate concentration solution of the second generator The concentrated solution of the third generator is guided to the third generator via the third heat exchanger, heated by the refrigerant vapor generated from the second generator and separated into a concentrated solution and a refrigerant vapor. Through the first absorber, absorbs the refrigerant vapor from the evaporator again, guides the refrigerant vapor generated in the second generator to the third generator, heats and concentrates the intermediate-concentration solution to condense it into the condenser. Sending the refrigerant vapor generated in the third generator to the condenser, giving latent heat to the cooling water and condensing it, sending the refrigerant of the condenser to the evaporator, evaporating by taking away heat from the cooling water for cooling, and cooling. Water absorbs heat of absorption in the first absorber and heat of condensation in the condenser, and further switches the first and second bypass lines to bypass the first generator and the second absorber. Constructed so that cooling can be performed in a double effect cycle Low temperature heat source using absorption heat pump consisting of Te.

[0007]

[Action]

1. Cycle at the time of heating Pumping heat from a low-temperature heat source in the evaporator and evaporating the refrigerant vapor is absorbed in the absorbing solution in the first absorber. First
The dilute solution in the absorber passes through the first heat exchanger by the solution pump, is led to the first generator, is heated by the low-temperature water, and is separated into the refrigerant vapor and the concentrated solution. The concentrated solution separated in the first generator passes through the first heat exchanger 4, is sent to the first absorber, and circulates between the first absorber and the first generator by absorbing the refrigerant vapor again. I do. Further, the refrigerant vapor generated in the first generator is absorbed in the absorbing solution in the second absorber. The dilute solution in the second absorber 5 is led to the second generator through the second heat exchanger and the third heat exchanger by the solution pump, and is heated by steam (high-temperature heat source) to be converted into an intermediate concentration solution and refrigerant vapor. Separated. The intermediate concentration solution separated in the second generator is led to the third generator via the third heat exchanger, and further heated by the refrigerant vapor generated in the second generator to be separated into a concentrated solution and refrigerant vapor. You. The concentrated solution separated in the third generator is sent to the second absorber through the second heat exchanger and absorbs the refrigerant vapor generated again from the first generator, so that the absorbing solution becomes the second absorber, The circulation is performed in the order of the second generator and the third generator. The refrigerant vapor generated in the second generator is led to the third generator, where the intermediate solution is heated and concentrated, condensed, and then led to the condenser. Also,
The refrigerant vapor generated in the third generator is also guided to the condenser 8 and condenses by giving latent heat to the cooling water (here, hot water for heating). The refrigerant in the condenser is sent to the evaporator 1 and pumps up the heat of the low-temperature heat source to evaporate. During the repetition of the above cycle, the hot water for heating in the hot water extraction line flows in the order of the first absorber, the second absorber, and the condenser, and the first absorber, the second absorber,
The temperature is increased by receiving heat of absorption in the absorber and heat of condensation in the condenser, and circulates in the radiator.

[0008] 2. Cooling cycle The refrigerant vapor generated by removing heat from the cooling water in the evaporator is absorbed by the absorbing solution in the first absorber. First
The dilute solution in the absorber is supplied to the first heat exchanger and the third
It is guided to the second generator via the heat exchanger, and is separated into an intermediate concentration solution and a refrigerant vapor by being heated by the vapor. The intermediate-concentration solution of the second generator is guided to the third generator via the third heat exchanger, and is heated by the refrigerant vapor generated from the second generator to be separated into a concentrated solution and refrigerant vapor. The concentrated solution of the third generator is led to the first absorber via the first heat exchanger, and absorbs the refrigerant vapor from the evaporator again. The refrigerant vapor generated in the second generator is guided to the third generator, where the intermediate-concentration solution is heated and concentrated, condensed, and sent to the condenser. Third
Refrigerant vapor generated in the generator is guided to the condenser, and condenses by giving latent heat to the cooling water. The refrigerant in the condenser is sent to the evaporator, and evaporates by removing heat from the cooling water for cooling. The cooling water takes away heat of absorption in the first absorber and heat of condensation in the condenser. That is, between the first heat exchanger and the first generator and between the second heat exchanger and the third heat exchanger, between the third generator and the second heat exchanger, and between the first generator and the first heat exchanger. By providing the first and second bypass lines between the exchangers and switching to the bypass side, the first generator and the second absorber are bypassed, and during cooling, cold water is supplied through the heat source water line. By taking it out, it becomes possible to perform cooling in a normal double-effect cycle.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, 1 is an evaporator, 2 is a first absorber,
3 is a first generator, 4 is a first heat exchanger, 5 is a second absorber,
6 is a second generator, 7 is a third generator, 8 is a condenser, 9 is a second heat exchanger, 10 is a third heat exchanger, and 11 is a heat source water line (cold water) passed through the evaporator 1. Line, 12 is a hot water extraction line (cooling water line) passing from the first absorber 2 through the second absorber 5 and circulating through the condenser 8, 13 is a low temperature water line circulating in the first generator 3, Reference numeral 14 denotes a second dilute solution line 21 which branches out of the first dilute solution line 20 from the first absorber 2 and reaches the first generator 3 by the three-way valve 15 and extends from the second absorber 5 to the second generator 6.
A first bypass line for cooling switching connected to a three-way valve 16 is connected to a third concentrated solution line 23 extending from the third generator 7 to the second absorber 5 by a three-way valve 18. From first
A second bypass line for cooling switching, which is connected to a first concentrated solution line 22 leading to the absorber 2 by a three-way valve 19, 24 is a heated steam line for heating the inside of the second generator 6, 25, 26, 27, 28
Is a steam line. Next, an operation example of the above embodiment will be described.

[0010] 1. Heating operation cycle In the evaporator 1, the refrigerant vapor pumped up from the low-temperature heat source and evaporated is absorbed in the absorption solution in the first absorber 2.
The dilute solution in the first absorber 2 passes through the first heat exchanger 4 by the solution pump, is led to the first generator 3 and is heated by low-temperature water to be separated into refrigerant vapor and a concentrated solution. The concentrated solution separated in the first generator 3 passes through the first heat exchanger 4 and is sent to the first absorber 2, where the concentrated solution is again absorbed by the refrigerant vapor so that the first absorber 2 and the first generator 3 are absorbed. Circulating between
Further, the refrigerant vapor generated in the first generator 3 is absorbed in the absorbing solution in the second absorber 5. The dilute solution in the second absorber 5 is led to the second generator 6 via the second heat exchanger 9 and the third heat exchanger 10 by the solution pump, and is heated by steam (high-temperature heat source) to receive the intermediate solution and the refrigerant. Separated with steam. The intermediate-concentration solution separated in the second generator 6 is guided to the third generator 7 through the third heat exchanger 10, and further heated by the refrigerant vapor generated in the second generator 6, and is further heated by the refrigerant vapor. And separated. The concentrated solution separated in the third generator 7 is sent to the second absorber 5 through the second heat exchanger 9 and absorbs the refrigerant vapor generated by the first generator 3 again, so that the absorbing solution becomes the second solution. It circulates in the order of the two absorbers 5, the second generator 6, and the third generator 7. The refrigerant vapor generated in the second generator 6 is guided to the third generator 7, where the intermediate solution is heated and concentrated, condensed, and then guided to the condenser 8. The refrigerant vapor generated in the third generator 7 is also guided to the condenser 8 and condenses by giving latent heat to the cooling water (here, hot water for heating). The refrigerant in the condenser 8 is sent to the evaporator 1 and pumps up the heat of the low-temperature heat source to evaporate. During the repetition of the above-described cycle, the hot water for heating in the hot water extraction line 12 flows in the order of the first absorber 2, the second absorber 5, and the condenser 8, and the first absorber 2, the second absorber 5 In the heat of absorption,
In the condenser 8, the temperature is raised by receiving the heat of condensation, respectively, and reaches a radiator (not shown) to perform heating.

2. Cooling operation cycle Refrigerant vapor generated by removing heat from a low-temperature heat source in the evaporator 1 is absorbed in the absorption solution in the first absorber 2. The dilute solution in the first absorber 2 is guided to the second generator 6 through the first heat exchanger 4 and the third heat exchanger 10 by a solution pump, and is heated by steam to be converted into an intermediate concentration solution and refrigerant vapor. Separated. The intermediate-concentration solution of the second generator 6 is guided to the third generator 7 through the third heat exchanger 10 and is heated by the refrigerant vapor generated from the second generator 6 to be converted into a concentrated solution and refrigerant vapor. Separated. The concentrated solution in the third generator 7 is guided to the first absorber 2 via the first heat exchanger 4 and absorbs the refrigerant vapor from the evaporator 1 again. The refrigerant vapor generated in the second generator 6 is guided to the third generator 7, where the intermediate-concentration solution is heated and concentrated, condensed, and sent to the condenser 8. Refrigerant vapor generated in the third generator 7 is guided to the condenser 8 and is supplied to the cooling water line 12.
Gives latent heat to the cooling water passing through and condenses it. The refrigerant in the condenser 8 is sent to the evaporator 1 and evaporates by removing heat from cooling water for cooling. The cooling water takes away heat of absorption in the first absorber 2 and heat of condensation in the condenser 8. That is, as shown in FIG. 1, between the first heat exchanger 4 and the first generator 3 and between the second heat exchanger 9 and the third heat exchanger 10, between the third generator 7 and the second heat exchanger. By providing a three-way valve for cooling switching and bypass lines 14 and 17 for cooling and heating between the units 9 and between the first generator 3 and the first heat exchanger 4, the first generator 4 and the second generator By bypassing the absorber 5 and taking out a cold water from the heat source water line 11 at the time of heating in a normal double effect cycle at the time of cooling, and circulating in the radiator to perform cooling.

Next, an example of calculation conditions for an absorption heat pump using the above embodiment will be described.

[0013] 1. Initial conditions (1) Cold water temperature Inlet 12 ° C Outlet 9 ° C (2) Low temperature hot water temperature for heating Inlet 70 ° C Outlet 65 ° C (3) Steam pressure for heating 5 kg / cm ² G (4) Hot water temperature Inlet 40 ° C Outlet 45 ° C 2. Cycle conditions used for calculation The cycle conditions of the new cycle determined from the initial conditions are shown below.

[0014] (1) evaporator temperature t _E 7.5 ° C. The pressure P _E 8 mmHg (2) the absorber first pressure P _E 8 mmHg second pressure P _CE 14 mmHg (3) condenser temperature t _C 47 ° C. The pressure P _C 80 mmHg (4) regenerator first pressure P _CE 14 mmHg second pressure P _C 80 mmHg third pressure P _C 589 mmHg (5) solution concentration lower stage diluted solution xi] _L1 60.0% concentrated solution xi] _L2 63.0% higher stage Side Dilute solution ξ _H1 55.2% Intermediate solution ξ _H2 57.0% Concentrated solution ξ _H2 58.2% 3. Conventional system used for comparison Single-effect absorption heat pump + low-temperature exhaust heat recovery hot-water heat exchanger Comparison results <Example of calculation results> When obtaining 100 kcal / h of hot water for heating New cycle Low-temperature water waste heat usage 40.4 kcal / h Steam consumption 30.0 kcal / h Conventional system Low-temperature water waste heat usage 40.4 kcal / h Steam consumption 35.1 kcal / h Steam consumption reduction rate (35.1−30.0) /35.1×100 = 1
From 4.5% or more, when the same low-temperature water exhaust heat is used, steam consumption can be reduced by about 15% compared to the conventional system.

FIG. 2 shows a During diagram during the new cycle operation.

[0016]

Since the present invention has the above-described structure and operation, in the heating operation, it is possible to reduce the steam consumption by about 15% to perform the efficient operation and to perform the cooling only by switching the three-way valve. Sometimes a double effect cycle operation can be performed.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an embodiment of a heat pump according to the present invention.

FIG. 2 is an explanatory diagram of a During diagram in the case of an embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Evaporator 2 1st absorber 3 1st generator 4 1st heat exchanger 5 2nd absorber 6 2nd generator 7 3rd generator 8 Condenser 9 2nd heat exchanger 10 3rd heat exchanger 11 Heat source water line (cold water line) 12 Hot water extraction line (cooling water line) 13 Low temperature water line 14 First bypass line 15, 16 Three-way valve 17 Second bypass line 18, 19 Three-way valve 20 First dilute solution line 21 Second Dilute solution line 22 First concentrated solution line 23 Second concentrated solution line 24 Heated steam line

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-37262 (JP, A) JP-A-62-272068 (JP, A) JP-A-59-32762 (JP, A) (58) Field (Int. Cl. ⁷ , DB name) F25B 15/00 303 F25B 30/04 520

Claims (1)

(57) [Claims] 1. An evaporator, a first absorber, a first generator, a first
From the heat exchanger, the second absorber, the second generator, the third generator, the condenser, the second heat exchanger, the third heat exchanger, the heat source water line passed through the evaporator, and the first absorber A hot water extraction line circulating through the condenser through the second absorber, a low temperature water line circulating through the first generator, and a first dilute solution line exiting from the first absorber and reaching the first generator are branched. A first bypass line for cooling switching connected to a second dilute solution line from the second absorber to the second generator, and a second concentrated solution line from the third generator to the second absorber. In the heating cycle, a second bypass line for switching cooling is connected to a first concentrated solution line from the first generator to the first absorber.
In the evaporator, heat is drawn from the low-temperature heat source and the evaporated refrigerant vapor is absorbed in the absorption solution in the first absorber, and the diluted solution in the first absorber is passed through the first heat exchanger by the solution pump,
Heated by the low-temperature water led to the first generator to separate into a refrigerant vapor and a concentrated solution, the concentrated solution separated in the first generator is passed through the first heat exchanger, sent to the first absorber, and again. The refrigerant vapor is absorbed and circulated between the first absorber and the first generator, and the refrigerant vapor generated in the first generator is absorbed in the absorption solution in the second absorber, and the diluted solution in the second absorber is removed. The solution pump passes through the second heat exchanger and the third heat exchanger to the second generator and is heated by steam (high-temperature heat source) to be separated into an intermediate-concentration solution and a refrigerant vapor, which is then separated in the second generator. Guiding the concentrated solution through a third heat exchanger to a third generator,
The refrigerant vapor generated in the second generator is further heated to separate it into a concentrated solution and a refrigerant vapor, and the concentrated solution separated in the third generator is sent to the second absorber via the second heat exchanger and again. The refrigerant vapor generated from the first generator is absorbed, the absorbing solution is circulated in the order of the second absorber, the second generator, and the third generator, and the refrigerant vapor generated in the second generator is generated in the third generator. After the intermediate solution is heated, concentrated and condensed, and condensed, it is guided to the condenser 8, and the refrigerant vapor generated in the third generator is guided to the condenser, and the cooling water (here, hot water for heating)
Gives latent heat to the condensate, the refrigerant of the condenser is sent to the evaporator,
The heat of the low-temperature heat source is pumped and evaporated, and the warm water for heating flows through the hot water take-out line in the order of the first absorber, the second absorber, and the condenser, and is absorbed in the first absorber and the second absorber. Heat and heat are condensed in the condenser to raise the temperature and circulate through the radiator. In the cooling cycle, the refrigerant vapor generated by removing heat from the heat source water line in the evaporator is first absorbed. The dilute solution in the first absorber is introduced into the second generator via the first heat exchanger and the third heat exchanger by the solution pump, and is heated by the steam to be heated to the intermediate concentration solution and the refrigerant vapor. And the intermediate concentration solution of the second generator is led to the third generator via the third heat exchanger, and heated by the refrigerant vapor generated from the second generator to be separated into the concentrated solution and the refrigerant vapor. Then, the concentrated solution of the third generator is passed through the first heat exchanger to the first suction port. Lead to the collector,
The refrigerant vapor from the evaporator is again absorbed, the refrigerant vapor generated in the second generator is led to the third generator, the intermediate concentration solution is heated and concentrated, condensed, sent to the condenser, and generated in the third generator. The refrigerant vapor is led to the condenser and condenses by giving latent heat to the cooling water, and the refrigerant in the condenser is sent to the evaporator to take heat from the cooling water for cooling and evaporate, and the cooling water is absorbed by the first absorber. In heat and condenser, it takes away heat of condensation,
And using a low-temperature heat source configured to switch the second bypass line to bypass the first generator and the second absorber and to perform cooling in a normal double effect cycle during cooling. Absorption heat pump.