JPS58203368A - Absorption type cold and hot water machine - 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 The present invention relates to a water-lithium bromide absorption type water chiller/heater that is frequently used for air conditioning, etc., and in particular, it recovers heat from the exhaust gas of a boiler installed in a high-temperature regenerator to cool the air conditioner.

The present invention relates to an absorption type water chiller/heater suitable for improving heat utilization efficiency in heating.

As shown in Fig. 1, the conventional water chiller/heater of this type has an evaporator 1.
．． Absorber 2. Condenser 3. High temperature regenerator 4° low temperature regenerator 5.
Low temperature heat exchanger6. High temperature heat exchanger 7° circulation pump 8. Solution spray ejector pump9. Refrigerant spray pump 10. It consists of a boiler 11 that heats the high temperature regenerator 4.

During cooling operation, valve 14 is closed. A mixed solution of water and lithium bromide (hereinafter abbreviated as solution) in the high-temperature regenerator 4 is heated by the combustion gas of the boiler 11 and becomes refrigerant vapor (steam).
occurs. The generated refrigerant vapor is led to the low-temperature regenerator 5, heats the solution in the low-temperature regenerator 5, condenses it into a liquid, and supplies the solution to the condenser 3 via the outlet header 16. The solution in the low temperature regenerator 5 is heated by the refrigerant vapor generated in the high temperature regenerator 4 to generate refrigerant vapor. The refrigerant vapor is led to the condenser 3, cooled by the cooling water 13 flowing in the heat transfer tube, condensed and liquefied, heated the low temperature regenerator 5 and sent to the evaporator 1 together with the condensed and liquefied refrigerant through the valve 25. Supplied. The liquid refrigerant supplied to the evaporator 1 is sprayed onto the heat transfer tube group by the refrigerant spray pump 10, exchanges heat with the cold water 12 flowing inside the heat transfer tubes, evaporates and vaporizes, and deprives the cold water 12 of the latent heat of evaporation. This cools the cold water 12 and provides a refrigeration effect. Refrigerant vapor evaporated in the evaporator 1 is guided to the absorber 2. On the other hand, the solution concentrated by generating refrigerant vapor in the high-temperature regenerator 4 (hereinafter referred to as concentrated solution) and the concentrated solution in the low-temperature regenerator 5 pass through the high-temperature heat exchanger 7 and the low-temperature heat exchanger 6, respectively. The solution is sucked into the solution ejector spray pump 9 driven by the high-pressure solution of the circulation pump 8, is pressurized, is spread over the heat transfer tube group of the absorber 2, and is cooled by the cooling water 13 flowing inside the heat transfer tubes. The refrigerant vapor evaporated in the evaporator 1 is absorbed and diluted to form a dilute solution. The dilute solution in the absorber 2 is sucked and pressurized by the circulation pump 8, preheated by the low temperature heat exchanger 6, and sent to the low temperature regenerator 5, and a portion is preheated by the high temperature heat exchanger and sent to the high temperature regenerator 4, respectively. Supplied. The cooling cycle was configured as explained above.

Next, heating operation will be explained. High temperature regenerator 4 during heating
A common method is to indirectly heat the hot water 13 flowing in the absorber 2 and condenser 3 with refrigerant vapor generated from a solution heated by a boiler 11 installed in the absorber 2 and the condenser 3. For example, when the valve 14 is opened and the valves 20° 21.22, 23, 24.25 are closed, the refrigerant vapor generated in the high temperature regenerator 4 heats the solution in the low temperature regenerator 5, and the refrigerant vapor itself is condensed and liquefied. Valve 14 again
and then returns to the high temperature regenerator 4. The refrigerant vapor generated by being heated by the refrigerant vapor of the high-temperature regenerator 4 in the low-temperature regenerator 5 heats the hot water 13 flowing in the heat transfer tube of the condenser 3, and is condensed and liquefied, and then regenerated into the low-temperature regenerator 5. The air is returned through the bypass flow path (5♀ not shown, closed during cooling). The heating cycle was configured as described above.

In the above-mentioned direct-heating double-effect absorption type water chiller/heater,
The solution in the high-temperature regenerator 4 is at a temperature level of approximately 140 to 170C, and the combustion exhaust gas discharged from the boiler 11 is discarded into the atmosphere at a high temperature of 140 to 170C or higher. The efficiency was not sufficient because it was not used.

An object of the present invention is to provide a heat exchanger in the flue gas passage of the boiler 11 provided in the high-temperature regenerator 4 and recover heat to the low-temperature regenerator 5 using the high-temperature liquid refrigerant of the low-temperature regenerator 5. In addition to improving the heat utilization efficiency of cooling and heating, problems caused by the heat exchanger arrangement, such as retention of surfactant and leakage of refrigerant vapor to the condenser, are addressed.

An object of the present invention is to provide an absorption type water chiller/heater that prevents an increase in heat loss due to an increase in the temperature of a liquid refrigerant flowing out of a condenser.

A heat exchanger is disposed in the flue gas flow path of the boiler 11 provided in the high-temperature regenerator 4 to supply part or all of the condensed liquid refrigerant of the low-temperature regenerator 5, and the generated refrigerant vapor is transferred to the low-temperature regenerator 5. In addition to using the liquid refrigerant for heating, the remaining liquid refrigerant is supplied to the condenser 3 during cooling and to the high-temperature regenerator 4 during heating to (1) maintain an appropriate level of liquid refrigerant in the heat exchanger; The outflow amount of the liquid refrigerant accompanying the refrigerant vapor is reduced so that the liquid refrigerant does not inhibit the concentration of the solution in the high temperature regenerator 4 during cooling.

(11) Supplying liquid refrigerant in an amount greater than the amount of evaporation to prevent the refrigerant in the heat exchanger from becoming a solution (causing a rise in boiling point) due to the trace amount of solution contained in the liquid refrigerant flowing into the heat exchanger remaining without evaporation. This was prevented by draining the refrigerant again as a liquid refrigerant.

0il) The refrigerant in the heat exchanger is converted into a surfactant by a small amount of surfactant (for example, n-octyl alcohol) contained in the liquid refrigerant flowing into the heat exchanger remaining without evaporation, in the same manner as in (11). Prevented.

It is characterized by Furthermore, when the heat exchanger and the condenser 3 are connected as described above, the refrigerant vapor generated in the heat exchanger flows into the condenser 3 together with the liquid refrigerant, resulting in heat loss (refrigerant vapor is mixed with the liquid refrigerant). Approximately 500 kcat/compared to the case of
It was found that the enthalpy is large and the heat loss is also large by Kf. Therefore, in order to prevent refrigerant vapor from flowing out, a control valve (for example, a float valve) that opens and closes depending on the refrigerant liquid level in the heat exchanger is disposed in the refrigerant conduit connecting the heat exchanger and the condenser 3. shall be. Furthermore, the liquid refrigerant in the heat exchanger is supplied to the heat exchanger by the flow pressure loss of the duct connecting the heat exchanger and the heating section of the low-temperature regenerator 5 and the heating pipe 5a of the low-temperature regenerator 5. It was found that the temperature was higher than that of the liquid refrigerant. If the liquid refrigerant in the heat exchanger is supplied as it is to the condenser 3, heat loss will be large. Therefore, the present invention is characterized in that heat is exchanged between the solution sent from the absorber 2 to the high temperature regenerator 4 and the low temperature regenerator 5, and the liquid refrigerant sent from the heat exchanger to the condenser.

Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 2 to 6, the same or equivalent parts are given the same reference numerals as those shown in FIG. 1, and their explanation will be omitted. 2 and 3, 30 is a heat exchanger disposed in the exhaust path 37 of the combustion exhaust gas G generated by the boiler 11, and the heat exchanger 30 is connected to the lower header 31.
and the upper ladder 32 which also serves as a steam/water separator, and its header 3.
It consists of a large number of heat exchanger tubes connected to 1.32 and a large number of fins planted on these heat exchanger tubes. The lower ladder 31 and the liquid refrigerant outlet header 16 of the low temperature regenerator 5 are connected by a refrigerant conduit 33 . The upper header 32 is connected at its lower part via a valve 34 to the gas phase of the high-temperature regenerator 4 and via a valve 20 to the condenser 3 via a liquid refrigerant line 35 . Further, a steam pipe 17 that connects the high temperature regenerator 4 and the low temperature regenerator 50 inlet steam header 18 is connected to the top of the ladder 32 via a steam duct 36 .

Next, the operation and effects of this embodiment having the above-described configuration will be explained.

During cooling operation, the gate valve 34 is closed, and the gate valves 3g and 2 are closed.
1, 22, 23, 24. Set 25 to open state. The liquid refrigerant condensed and liquefied in the heating pipe 5a of the low-temperature regenerator 5 is introduced into the heat exchanger 30 via the outlet header 16 and the conduit 33, and is then discharged from the combustion exhaust of the boiler 11.

It exchanges heat with gas and generates refrigerant vapor of 86C to 96tr. This refrigerant vapor is led to the steam duct 36 and the steam pipe 17 through an eliminator (not shown), and is led together with the refrigerant vapor generated in the high temperature regenerator 4 to the heating pipe 5a through the inlet header 18 of the low temperature regenerator 5. The solution is condensed and liquefied, and the solution in the low-temperature regenerator 5 is heated by the radiation of latent heat at that time, thereby generating refrigerant vapor and concentrating the solution. The liquefied refrigerant is again introduced into the heat exchanger 30 via the outlet header 16 and the conduit 33. The liquid refrigerant in the heat exchanger 30 is discharged to the condenser 3 via the conduit 35 and the gate valve 38 in an amount equal to the amount of refrigerant vapor generated in the high temperature regenerator 4.

Therefore, it was possible to prevent the heat exchanger 30 from overflowing with liquid refrigerant and the liquid refrigerant flowing into the high-temperature regenerator 4 through the steam duct 36 and the steam pipe 17, thereby inhibiting the concentration action of the solution. The refrigerant vapor generated in the high-temperature regenerator 4 contains vapor of a surfactant (for example, n-octyl alcohol) that has the effect of promoting heat transfer in the absorber 2 and fine solution mist. The surfactant is generally a higher alcohol type having a higher boiling point than the refrigerant (water). In the heat exchanger 30, since refrigerant vapor is generated at a lower temperature than in the high-temperature regenerator 4, the surfactant remains, but (9) is discharged together with the liquid refrigerant to the condenser 3 through the conduit 35.

Therefore, the concentration of the surfactant and the concentration of the solution in the heat exchanger 30 are extremely low, and these impurities hardly cause an increase in the boiling point. Therefore, the pressure level of the heat exchanger 30 is almost the same as that of the high temperature regenerator 4, whereas the temperature level of the heated medium is 60-70C lower and the boiler 11
The temperature is at a level that allows sufficient heat exchange with the exhaust gas. As described above, the heat of the exhaust gas from the boiler 11 is transferred to the low temperature regenerator 5.
It is recovered into a solution and used for concentrating the solution and generating refrigerant, contributing to an increase in the refrigerating capacity of the absorption type water chiller/heater.

Usually, the solution temperatures in the low-temperature regenerator 5 and the high-temperature regenerator 4 are 80 to 90C and 130 to 160C, respectively, and the exhaust gas temperature in the boiler 11 is about 200t:'.

The boiling point of the refrigerant in the heat exchanger 30 is 86-96C, which is higher than the solution temperature in the low-temperature regenerator 5, and it is easy to make the exhaust gas temperature level after heat exchange in the heat exchanger 30 about 1000. From this, approximately 5% of the heat input to the boiler 11 will be recovered (10), and as a result, the refrigerating capacity will be increased by 70 to 80 inches of recovered heat. In other words, the coefficient of performance based on heat input can be improved by about 4%, resulting in the effect of saving energy.

During heating operation, the gate valve 34 is opened, the gate valves 38,
21, 22, 23, and 24.25 are set to the closed state.

The liquid refrigerant condensed and liquefied in the heating pipe 5a of the low-temperature regenerator 5 is introduced into the heat exchanger 30 via the outlet header 16 and the conduit 33, where it exchanges heat with the combustion exhaust gas of the boiler 11 to generate refrigerant vapor. Further, the remaining liquid refrigerant is returned to the gas phase portion of the high temperature regenerator 4 via the valve 34. This refrigerant vapor is guided through an eliminator (not shown) to the steam duct 36 and the steam pipe 17, and together with the refrigerant vapor generated in the high temperature regenerator 4, is led to the heating pipe 5a through the inlet header 18 of the low temperature regenerator, where it is condensed. Liquefied 1. The latent heat released at this time heats the solution in the low-temperature regenerator 5 and generates refrigerant vapor. The refrigerant vapor generated in the low-temperature regenerator 5 is led to the condenser 3, heats the hot water 13 flowing in the heat transfer tube, condenses and liquefies it, and returns to the low-temperature regenerator 5 (11) again. As described above, the heat of the exhaust gas from the boiler 11 is recovered into hot water.

The effect of heat recovery is different from that during cooling, and the effect is based on the entire amount of heat recovered, resulting in energy savings of approximately 5.5 cm.

Next, another embodiment of the present invention will be explained with reference to FIG. This embodiment and the above-mentioned embodiments are such that the outlet water chamber 16 of the low-temperature regenerator 5 and the heat exchanger 30 are connected via a gate valve 39, and the heat exchanger 30 and the steam pipe 17 are connected to each other via a gate valve 39.
The conventional cycle has a refrigerant flow path system, that is, a system that connects the condenser 3 and the outlet water chamber 16 via the gate valve 20, and the high-temperature regenerator 4.
The difference is that the system connecting the gas phase and the outlet ice chamber 16 remains. As described above, by closing the gate valves 40, 39, 34, it becomes easy to disconnect the exhaust heat recovery heat exchanger i, 30 from the main cycle of the water cooler/heater. Therefore, there is an advantage that the heat recovery heat exchanger 30 can be easily installed in an existing water cooler/heater.

Note that since the non-condensable gas (12) remains in the outlet water chamber 16, a bleed pipe 45 is provided.

Next, the operation will be explained. When cooling, use the gate valve 20°21.
22, 23, 24, 25, 38, 39° 40 are set in the open state and the gate valves 14 and 34 are set in the closed state. The condensate refrigerant of the low-temperature regenerator 5 is supplied to the outlet ice chamber 16, and a portion is supplied to the gate valve 20.
to the condenser 3 via the gate valve 39, and the rest to the heat exchanger 3 via the gate valve 39.
0. The refrigerant vapor generated in the heat exchanger 30 passes through the gate valve 40, the duct 36, the steam pipe 17, and the inlet ice chamber 18, and is supplied to the low-temperature regenerator 5 together with the refrigerant vapor generated in the high-temperature regenerator 4 to heat the solution. Further, the remaining liquid refrigerant is sent to the condenser 3 via the gate valve 38 and the conduit 35. In addition,
Even if the liquid refrigerant outlet of the conduit 35 is attached to the ladder 31 at the bottom, the refrigerant liquid level of the heat exchanger 30 is maintained at an appropriately balanced position. An appropriately balanced position is a point where the liquid head of the heat exchanger 30 and the pressure drop of the duct 36, the steam pipe 17, and the heat transfer tube 5a are balanced in consideration of the liquid head of the liquid refrigerant conduit 33 and the flow pressure drop thereof.

(13) During heating, gate valves 20, 21, 22, 23°24.2
5.38 to the closed state, and the gate valve 14, 34°39.40 to the open state. A portion of the liquid refrigerant in the outlet water chamber 16 returns to the high temperature regenerator 4 via the gate valve 14. The remaining liquid refrigerant is introduced into the transthermal exchanger 30 through a conduit 33 and a gate valve 39, and exchanges heat with the exhaust gas of the boiler 11 to generate refrigerant vapor. The generated refrigerant vapor is supplied to the low-temperature regenerator 5 together with the refrigerant vapor generated in the high-temperature regenerator 4 through the duct 36, the gate valve 40, the steam pipe 17, and the inlet duct 18, and the solution in the low-temperature regenerator 5 is heat up. Further, the remaining liquid refrigerant is returned to the high temperature regenerator 4 via the gate valve 34. As described above, the heat of the exhaust gas from the boiler 11 is recovered into the solution in the low temperature regenerator 5.

The effects are as described above.

However, a portion (about 1 inch) of the refrigerant vapor generated in the heat exchanger 30 is discharged to the condenser 3 via the conduit 35.

The following methods can be used to prevent heat loss caused by this. This invention will be explained below using FIG. 5.

(14) A float chamber 42 is connected to the heat exchanger 30 via a weir 43, and is connected to the condenser 3 via a conduit 35 via a float valve 41 and a gate valve 38. The float valve 41 is closed when the refrigerant liquid level in the float chamber 42 decreases, and refrigerant vapor is not discharged into the conduit 35, so there is no heat loss due to vapor outflow, and the effect of heat recovery can be further enhanced. Furthermore, while the liquid level in the heat exchanger 30 is undulating due to boiling of the refrigerant, the float chamber 42 is filled with liquid refrigerant overflowing the weir 43, which causes the float valve 41 to vibrate abnormally. This is advantageous in terms of durability of the float valve 41.

By the way, as mentioned above, the temperature level of the liquid refrigerant in the heat exchanger 30 is about 2 to 3 times higher than that of the liquid refrigerant in the outlet ice chamber 16 of the low temperature regenerator 5 due to the pressure drop in the flow path and the refrigerant head.
C high. Therefore, the enthalpy of the liquid refrigerant supplied to the condenser 3 is large, and the improvement in thermal efficiency by heat recovery 1 is not sufficient. Therefore, an attempt was made to further improve the thermal efficiency by configuring the device as shown in FIG.

(15) In FIG. 6, the differences from the embodiment shown in FIG. 2 are as follows:
A conduit 35 connecting the heat exchanger 30 and the condenser 3 is provided with a heat exchanger 44 that exchanges heat with the solution pumped from the absorber 2 to the low-temperature heat exchanger 6 by the circulation pump 8.

The action of the heat exchanger 44 is to recover the sensible heat of the high temperature liquid refrigerant discharged from the heat exchanger 30 into a solution, and thereby to transfer the sensible heat to the condenser 3.
The thermal energy wasted into the cooling water 13 is further reduced, thereby increasing the heat utilization efficiency during cooling operation.

Note that even if refrigerant vapor is mixed into the liquid refrigerant discharged from the heat exchanger 30 to the conduit 35, heat can be recovered to the solution.

As explained above, in the first invention, a heat exchanger is disposed in the combustion gas exhaust path of the boiler to supply a high temperature liquid refrigerant to the low temperature regenerator, so that the solution in the low temperature regenerator is heated to a high temperature. It is configured to recover heat based on the principle of siphon (i.e., transferred by boiling and condensation of the refrigerant), and is configured to return excess liquid refrigerant to the condenser during cooling and to the high-temperature regenerator during heating. (16) (1) Since the liquid refrigerant in the heat exchanger does not become a solution or a surfactant, the boiling point of the refrigerant does not increase, and the heat recovery temperature can be maintained almost constant.

(2) Since heat can be recovered in the cycle during cooling and heating, the utilization efficiency of the heat exchanger is high and the energy saving effect per invested capital is large.

Further, by using the second invention in combination, (3) during cooling, it is possible to prevent the refrigerant vapor generated in the heat exchanger 30 from blowing through to the condenser, so that the heat utilization efficiency is improved accordingly.

Furthermore, by using the third invention in combination, (4) during cooling, the sensible heat of the high temperature liquid refrigerant heated by the heat exchanger 30 is recovered into a solution and then sent to the condenser. So,
Heat utilization efficiency is improved by the sensible heat of the liquid refrigerant.

There is an effect.

It is also conceivable that the liquid refrigerant introduced from the ladder 16 to the liquid refrigerant outlet of the low-temperature regenerator 5 into the heat exchanger 30 and the liquid refrigerant discharged from the heat exchanger 30 to the condenser 3 undergo heat exchange. This means that the liquid refrigerant introduced from the outlet ice chamber 16 (17) into the heat exchanger 30
This is because the temperature is lower than that of the liquid refrigerant discharged from 0 to the condenser 3. Therefore, there is an effect of reducing the reduction in efficiency due to refrigerant vapor being discharged to the condenser 3.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional absorption type water chiller/heater, Fig. 2 is a block diagram of an embodiment of the present invention, Fig. 3 is a partial detailed explanatory diagram of Fig. 2, Figs. 4 and 5, FIG. 6 is a block diagram of another embodiment of the present invention. 1... Evaporator, 2... Absorber, 3... Condenser, 4
... high temperature regenerator, 5 ... low temperature regenerator, 30 ... heat exchanger, 42 ... float box, 41 ... flow 11P, 44 ... heat exchanger for refrigerant sensible heat recovery, 45・
・Bleed air piping. Agent Patent Attorney Toshiyuki Usuda I Ql ;tl (21 2nd eye 3 closing

Claims (1)

[Claims] 1. A heat exchanger is provided in the exhaust path of the combustion gas of the boiler provided in the high-temperature regenerator, and the condensed liquid refrigerant of the low-temperature regenerator is supplied to the heat exchanger, and the refrigerant generated in the heat exchanger is The refrigerant vapor generated in the heat exchanger is supplied to the low-temperature regenerator along with the refrigerant vapor generated in the high-temperature regenerator, and the liquid refrigerant from the heat exchanger is supplied to the condenser during cooling operation and to the high-temperature regenerator during heating operation. Absorption type water chiller/heater. 2. A liquid refrigerant conduit connecting the heat exchanger and the condenser,
2. The absorption chiller/heater according to claim 1, further comprising a control valve that opens and closes depending on the liquid level of the liquid refrigerant in the heat exchanger. 3. Claim 1, characterized in that the liquid refrigerant supplied from the heat exchanger to the condenser and the solution supplied from the absorber to the low-temperature regenerator or the high-temperature regenerator are heat-exchanged.
The absorption type water chiller/heater according to item 1 or 2.