JPS58108369A - Method of recovering heat of exhaust gas of 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 an exhaust gas heat recovery method for an absorption type water chiller/heater suitable for improving heat utilization efficiency for cooling and heating by recovering heat from the exhaust gas of a boiler provided in a high-temperature regenerator.

This conventional Shiba cold water heater is shown in Figure 1.

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 1
0. It consists of a boiler 11 that heats the high temperature regenerator 4.

When producing cold water (during cooling operation), close the cooling/heating switching valve 14.
The refrigerant is spread over a group of heat transfer tubes through which the cold water 12 of the evaporator 1 escapes and evaporated, and this refrigerant gas is sent to the absorber 2. On the other hand, during hot water production (during heating operation), the cooling/heating switching valve 14 is opened, and the refrigerant is sent to the absorber 2 and mixed with the solution.

The above-mentioned tower water heater is installed as shown in Figure 2.

A heat exchanger 30 is disposed in the exhaust path of the combustion exhaust gas of the boiler 11, and a refrigerant conduit is connected between the lower part of the heat exchanger 30 and the liquid phase part of the outlet water chamber 16 of the low temperature regenerator 5 via the throttle valve 31. The upper part of the heat exchanger 30 and the inlet water chamber 17 of the low-temperature regenerator 5 are connected through a conduit 33, and the heat of the exhaust gas is transferred to the solution in the low-temperature regenerator 5 using the thermosiphon principle. A method of heat recovery was proposed.

However, in the above-described heat recovery method, liquid refrigerant accumulates in the heat transfer tubes of the heat exchanger 30 when the refrigerator is stopped, and when the refrigerator is restarted,
There are problems in that moisture in the exhaust gas condenses on the fins of the heat exchanger 30 for a relatively long period of time, and the deterioration is more significant than in the heat exchanger tubes used in the boiler 1. The reason for this is that once the moisture in the combustion exhaust gas condenses, the water droplets absorb strongly acidic and hygroscopic gases such as SO2 and HCJ in the exhaust gas. This is because it does not dry even at high temperatures (approximately 70 to SO, C>).

The purpose of the present invention is to recover heat from the exhaust gas of the boiler installed in the high-temperature regenerator during cooling and heating operations, and to prevent condensation and fog formation on the heat recovery heat exchanger installed in the exhaust path of the boiler. An object of the present invention is to provide a method for recovering exhaust gas heat from an absorption type water chiller/heater, which prevents corrosion damage to a heat exchanger caused by water.

This invention is a boiler using kerosene or gas as fuel)1
Once the moisture in the combustion exhaust gas in No. 1 condenses, the water droplets contained in the exhaust gas will be 80. This was done because strongly acidic and hygroscopic gases such as HCA are absorbed, so even if heat is recovered at a relatively high temperature, corrosion and deterioration of the heat recovery heat exchanger 30 described above progresses. When the water cooler/heater is started from a low temperature state, - the heat production recovery heat exchanger 30 is heated to about 100
It is characterized in that it can be heated dry to a high temperature of 0 or higher to expel fog water and absorbed gas (for example, 804.HCp, etc.).

Embodiments of the present invention will be described below with reference to the drawings. Among the reference numerals shown in FIGS. 3 to 5, the same reference numerals as those shown in FIGS. 1 and 2 indicate the same parts.

In FIG. 3, a boiler 11 installed in the high temperature regenerator 4
A heat exchanger 30 is disposed in the exhaust path. The lower part of the heat exchanger 30 and the lower part of the outlet side water chamber 16 of the low temperature regenerator 5 are connected via a solenoid valve 40 and a refrigerant conduit 32. −
10,000, the upper part of the heat exchanger 30 and the heat transfer tube 5a of the low temperature regenerator 5
A part of the refrigerant conduit 32 is connected to the refrigerant conduit 32. Further, the heat exchanger 30 is arranged below the low temperature regenerator 4.

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

The refrigerant vapor generated in the high-temperature regenerator 4 is guided through the conduit 17° inlet ice chamber 18 into the heat transfer tube 5Jll of the low-temperature regenerator 5, where it is condensed and liquefied at about 70 to 80C, and the latent heat of condensation at that time is used to cool the refrigerant in the low-temperature regenerator. Heat the solution in 5.

The refrigerant (water) condensed and liquefied in the heat transfer tube 5a is transferred to the outlet water chamber 16.
It flows out into the condenser 3 via the conduit 19 due to the pressure difference. On the other hand, a part of the liquid refrigerant in the water chamber 16 flows down the conduit 32 with a head difference, exchanges heat with the exhaust gas in the heat exchanger 30, boils and evaporates, and becomes low-density refrigerant vapor.
3, it is guided to a part of the heat transfer tube 5a of the low temperature regenerator 5, exchanges heat with the solution, condenses and liquefies, and returns to the ice chamber 16 again. In this way, the heat of the exhaust gas from the boiler 11 is recovered to the solution in the low temperature regenerator 5.

Normally, the solution temperatures in the low-temperature regenerator 5 and the high-temperature regenerator 4 are 70-90C1 and 140-160C, respectively, so the exhaust gas temperature in the boiler 11 is higher than the solution temperature in the high-temperature regenerator 4, and the heat exchanger 30 The temperature of the exhaust gas after heat exchange is also higher than the temperature of the solution in the low-temperature regenerator 4. For example, if the exhaust gas temperature of the boiler 11 is 200C and the exhaust gas temperature of the heat exchanger 30 is 80C, about 6% of heat will be recovered, depending on the fuel and combustion conditions, and therefore the refrigeration capacity during cooling will be reduced by about 3%. %, or the heating capacity during heating can be increased by about 6%. In other words, the effect is that fuel can be saved by approximately 3% for cooling and approximately 6% for heating.

By the way, at startup, the heat exchanger 30 is at a low temperature p1, so moisture in the exhaust gas condenses on the heat exchanger 30. At this time, when the solenoid valve 40 is closed, the heat exchanger 30 evaporates the liquid refrigerant and the exhaust gas temperature of the L boiler 11 is 2, which is in an empty firing state.
Approaching 00C.

When the heat exchanger is heated to a temperature of about 1001:' or more in this way, the aforementioned condensed water and corrosive gas evaporate, resulting in a dry state. Is this state the temperature sensor installed in the heat exchanger 30? -41 is detected and the solenoid valve 40 is opened. Then,
The liquid refrigerant in the ice chamber 16 is guided to the heat exchanger 30 by the head difference, and heat is recovered as described above. In particular, during heating, it is assumed that the condensation temperature in the heat transfer tube of the low temperature regenerator 5 may be operated at around 60C, which is slightly higher than the temperature at which moisture in the exhaust gas condenses (approximately 50C). Since there are no water droplets adsorbing hygroscopic gas on the surface, no condensation occurs.

Note that in this embodiment, since the steam conduit 33 is connected to a part of the heat transfer tube 5 m of the low temperature regenerator 5, there is a phenomenon in which unevaporated droplets are heated by superheated steam from the high temperature regenerator and evaporate explosively. Since it does not occur, it has the effect of preventing noise.

Further, the solenoid valve 40 is replaced with the fuel control valve 115 of the boiler 11.
16, the refrigerant spray pump 10, the solution circulation pump 8, etc., via a delay relay 42 (not shown), the same effect as described above can be obtained. In this case, considering the heat capacity of the boiler 11 and the heat capacity of the heat exchanger 30, it is approximately 20 to 30 minutes in the 300 refrigeration ton class.

Note that when the supply of liquid refrigerant to the heat exchanger 30 is stopped when the operation is stopped, the liquid refrigerant remaining in the heat exchanger 30 is evaporated by residual heat. Therefore, there is an advantage that damage to the heat exchanger 30 due to freezing of the refrigerant in extremely cold weather can be prevented.

FIG. 4 is an explanatory diagram of another embodiment of the present invention.

In this embodiment, a steam/water separator 34 is provided in the middle of a refrigerant vapor conduit 33 connecting the heat exchanger 30 and the inlet ice chamber 18, and a return pipe 35 is provided to return the separated liquid refrigerant to the 300 Å port of the heat exchanger. This embodiment differs from the previous embodiment in that it has been set. With this configuration, the superheated steam flowing from the conduit 17 causes the conduit 3 to
Bumping of the refrigerant contained in the steam flowing in from 3 can be prevented.

This has the effect of preventing the so-called steam hammering phenomenon from occurring. Furthermore, since the amount of refrigerant circulated through the heat exchanger 30 can be increased, there is an effect that the heat exchange efficiency can be improved.

FIG. 5 is an explanatory diagram of another embodiment of the present invention.

In this embodiment, the heat exchanger 30 is placed at the same level as the low-temperature regenerator 5 or higher, and a pump 42 for supplying liquid refrigerant is installed.
is placed in the middle of the conduit 32 below the water chamber 16.
This embodiment differs from the embodiment shown in FIG. 3 in that the skeleton pump 42 has the same function as the electromagnetic valve 40 described above. Further, this embodiment differs from the embodiment shown in FIG. 3 in that the refrigerant vapor conduit 33 is connected to the sunrise sluice 16 of the low-temperature regenerator 5. The refrigerant vapor from the refrigerant vapor conduit 33 flows into the heat transfer tube 5m, condenses and liquefies, and returns to the water chamber 16 again. This has the advantage that the piping route of the heat exchanger 30 can be shortened.

Furthermore, since the pump 42 is used, there is a concern that the cost will increase. However, for example, in a 300 refrigeration ton dual-effect absorption chiller/heater, the coefficient of performance C, O, PW is 1.2° and the exhaust gas efficiency is 8.
0%, and if approximately 6% heat is recovered, the refrigerant circulation amount is approximately 15Kg/m! If you use I, you can use a small-capacity pump.

As explained above, the refrigerant supply to the heat exchanger that recovers heat from the combustion exhaust gas of the boiler is temporarily stopped, and the moisture and acidic hygroscopic gas condensed on the heat exchanger are evaporated, and the surface of the heat exchanger is Because heat can be recovered in a dry state.

(11) Even if heat is recovered to a temperature slightly higher than the temperature at which moisture in the combustion exhaust gas condenses, no condensation occurs, and therefore deterioration due to corrosion of the heat exchanger can be maintained at the same level as the boiler body.

(2) Since heat can be recovered to the low-temperature regenerator from the temperature of the exhaust gas from the boiler of the high-temperature regenerator of approximately 200C to approximately 80C, energy-saving operation of approximately 3% during cooling and approximately 6% during heating can be achieved.

There is an effect.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the cycle of a dual-effect absorption type water chiller/heater, Fig. 2 is a block diagram of the prior art, Fig. 3 is a block diagram of one embodiment of the present invention, and Fig. 4 is a diagram of another embodiment of the present invention. FIG. 5 is a block diagram of another embodiment of the present invention. l... Evaporator, 2... Absorber, 3... Condenser, 4
...High temperature regenerator %5...Low temperature regenerator, 11...Boiler, 16...Low temperature regenerator outlet ice chamber, 18...Low temperature regenerator inlet water chamber. 19... Liquid refrigerant conduit, G... Exhaust gas, 30... Heat exchanger, 31... Throttle valve, 32... Liquid refrigerant conduit, 3
3... Refrigerant vapor conduit, 40... Solenoid valve, 41...
Temperature sensor, 42--Delay relay, 43--Refrigerant supply pump. ”-1IfJ2 Figure 3

Claims (1)

[Claims] 1. A heat exchanger is provided in the combustion gas exhaust path of the boiler provided in the high-temperature regenerator, and the heat exchanger and the low-temperature regenerator heating section are connected through a liquid refrigerant conduit and a steam conduit. At the same time, a temperature sensor is installed in the heat exchanger, and the temperature sensor detects condensation, and the control valve installed in the liquid refrigerant pipe is closed, and the heat exchanger is heated dry to remove condensed water and moisture absorption. evaporate sexual gases,
A method for recovering exhaust gas heat from an absorption type water chiller/heater that detects this with a temperature sensor and opens the control valve again as a 4I symptom. 2. The exhaust gas heat recovery method for an absorption type water chiller/heater according to claim 1, characterized in that a refrigerant pump is disposed in the refrigerant conduit. Claim 1, characterized in that the control valve is opened via a delay relay when the water cooler/heater is started.
Exhaust gas heat recovery method for an absorption type water chiller/heater as described in .