CN1128964C

CN1128964C - Absorptive refrigerating circulation system

Info

Publication number: CN1128964C
Application number: CN00117124A
Authority: CN
Inventors: 王飞跃; 黄小池; 顾中平; 柳碧青
Original assignee: Guangdong Kelong Electrical Appliances Co Ltd
Current assignee: Guangdong Kelong Electrical Appliances Co Ltd
Priority date: 2000-05-30
Filing date: 2000-05-30
Publication date: 2003-11-26
Anticipated expiration: 2020-05-30
Also published as: CN1326081A

Abstract

The present invention relates to a novel absorptive refrigerating circulation system which has the structure that liquid butane is placed in an evaporator, and ammonia gases are filled in the evaporator so as to reduce the partial pressure of the liquid butane; a heat exchanger is used for providing the liquid butane for the evaporator and receiving mixed gases of butane and the ammonia gases, and the mixed gases are evaporated; a condenser /an absorber is used for receiving the evaporative gases, and after ammonia vapor is showered, the ammonia vapor is absorbed; simultaneously, the partial pressure of butane gases is improved, so that the butane gases are condensed, and the butane gases return to the evaporator through the heat exchanger; strong ammonia water is separated, the ammonia gases are sent into the evaporator, and water enters the condenser /the absorber. The novel absorptive refrigerating circulation system has the advantages of low material requirements, no work noise, long service life, high reliability, cleanliness and environmental protection.

Description

Novel absorption type refrigeration circulating system

Technical field

The present invention relates to Refrigeration Technique, more particularly, relate to a kind of novel absorption type refrigeration circulating system.

Background technology

Along with the mankind to the pay attention to day by day of environment problem and freon destruction to ozone layer, the Refrigeration Technique of seeking cleaning, environmental protection substitutes existing compression refrigeration circulation becomes the problem that refrigeration industry is more and more paid close attention to.In other words, the compression refrigeration of tradition freon is except bringing the destruction to the environment ozone layer, also have the big shortcoming of compressor operating noise, at present technical do not have as yet a kind ofly both can solve the environmental problem that freon brings, the technical scheme that can under low noise, work again.

Summary of the invention

The object of the present invention is to provide a kind of new refrigeration system, can overcome the above-mentioned shortcoming of prior art, both the non-environmental-pollution problem did not have any noise again.

The object of the present invention is achieved like this, construct a kind of novel absorption type refrigeration circulating system, adopt butane to make cold-producing medium, ammonia is made pressure equilibrium agent, water is made absorbent, its cyclic process is as follows: in the evaporimeter of liquefied butane is housed, pressure balance effect by the ammonia steam that injects, make the butane gas partial pressure reduce, make ammonia-butane mixed when over-heat-exchanger, evaporate, the ammonia steam that evaporates in the gas is being absorbed by water through there being water to water in the condensation/absorber of pouring, condensation turns back to evaporimeter through over-heat-exchanger under higher temperature thereby cause the butane partial pressure of vapor to rise simultaneously, and ammonia steam is absorbed into behind the concentrated ammonia liquor through separating device by water and makes its isolated ammonia part enter evaporimeter and isolated water section enters condenser and waters pouring through over-heat-exchanger.

In according to novel absorption type refrigeration circulating system provided by the invention, described separator comprises the heater that preheating is carried out in output to condenser, be used to produce the generator of ammonia and be used for the temporary liquid trap of collecting ammonia-aqueous mixtures, between described generator and described liquid trap, be connected with a bubble pump and be used for rare ammonia-water-soluble liquid pump with generator in described liquid trap, the ammonia steam that described generator produces under the effect of heater is delivered to heat exchanger, described liquid trap bottom has pipeline that water is sent back to described generator, and the aqueous water in the described generator sprays in described condenser by pipeline.

In the novel absorption type refrigeration circulating system that provides according to the utility model, system pressure is 4 crust.The temperature of described condenser is 315K.The temperature of described evaporimeter can be-25 ℃ to+40 ℃ scopes, and described evaporator temperature also can be 266K.Described generator temperature is 375K.Liquefied butane in the described condenser by siphon mode through the heat exchanger Returning evaporimeter.

Implement novel absorption type refrigeration circulating system of the present invention, have the following advantages:, can accomplish noiselessness or low noise owing to there is not the mechanical moving element of compressor, pump one class; Comparing with traditional ammonia-water-hydrogen absorption type refrigeration circulating system, is that diffusant (ammonia) is absorbed in this circulation, and traditional be that cold-producing medium (ammonia) is absorbed; Condenser in this circulation is identical with the internal pressure of evaporimeter, has reduced the requirement to material, and this circulatory system is totally-enclosed design simultaneously, and the life-span is long, reliability height, the heating efficiency height of cyclic process, cleaning, environmental protection.

Description of drawings

Below, in conjunction with the accompanying drawings and embodiments, further specify characteristics of the present invention, in the accompanying drawing:

Fig. 1 is the principle schematic of explanation novel absorption type refrigeration circulating system of the present invention;

Fig. 2 is ammonia-butane T-x-x-y schematic diagram;

Fig. 3 illustrates the influence curve of pressure variation to condenser and evaporator temperature;

Fig. 4 illustrates the influence curve of pressure variation to the coefficient of performance;

Fig. 5-Fig. 8 illustrates everywhere variations in temperature to the influence curve of the coefficient of performance.

The specific embodiment

As shown in Figure 1, novel absorption type refrigeration circulating system of the present invention is like this work: liquefied butane enters evaporimeter 200 by putting 2 from condenser 100.In evaporimeter 200, liquefied butane evaporates under saturation temperature, makes the cooling of butane and ammonia, and externally freezes.Ammonia-butane mixed vapour leaves evaporimeter 200 at point 3 and enters heat exchanger 300, the high temperature ammonia steam that cooling refluxes from generator 400 (point 5).Ammonia-butane superheated vapor flows out from putting 6 heat exchanger 300, enters because external heat reduces to continue the condenser 100 of lowering the temperature.Simultaneously, the aqueous water in the generator 400 sprays into condenser 100 at point 9.Water siphons away ammonia from ammonia-butane steam under the affinity effect.The absorption of ammonia steam is increased to degree near gross pressure with the dividing potential drop of butane steam, at this moment just can be under the saturation temperature of butane condensation.Because the density of butane and ammoniacal liquor is different, and ammoniacal liquor is immiscible with butane under the temperature and pressure of condenser, the density of liquefied butane is littler than liquid ammoniacal liquor, above butane floats over, at point 1 siphon Returning evaporimeter 200.Simultaneously, ammonia-aqueous mixtures leaves from condenser 100 bottoms, enters heat exchanger 300 (point 7).Mixture enters generator first preheating before here.In generator 400, drive away the ammonia steam of generation by 700 pairs of dense ammonia of heater-aqueous solution heating, the ammonia steam enters evaporimeter 200 (point 5).600 li of bubble pump 500 pumps to reservoirs of remaining rare ammonia-aqueous solution quilt point 8.600 li ammonia steams from the bubble pump of reservoir are all sent into condenser 100 (point 8).Rare ammonia-aqueous solution by solution heat exchanger with heat transferred from the dark liquid of the concentrated ammonia liquor of condenser.At last, water is sprayed into condenser 100.

Study in conjunction with low noise kind of refrigeration cycle thermodynamic behaviour, characteristics of the present invention are described, the vapor-liquid equilibrium thermodynamics dynamic performance model of ammonia-butane mixture, as shown in Figure 2, select the base example of ammonia-water-butane, selective system pressure 4bar, condenser temperature 315K, evaporator temperature 266K as the low noise kind of refrigeration cycle, generator temperature 375K, select cause description as follows:

The condenser temperature is elected 43 ℃ or 315K as, and heat can be loose in ambient air.Next, as shown in Figure 2, we have studied the change procedure of ammonia-butane mixture to determine the system pressure and the evaporator temperature of base example.We heat ammonia-aqueous mixtures of about 50/50 of the 315K that flows into from condenser in order to produce the ammonia steam, are heated to 375K and make that the mass concentration of ammonia is reduced to below 0.2 in the liquid, are unlikely to produce too many steam again.So the generator temperature in the basic example is decided to be 375K.

Fig. 2 explanation is under certain system pressure, and the characteristic of ammonia-butane mixture has limited the minimum and maximum temperature of evaporimeter and condenser respectively.Utilize these two limiting temperatures to improve temperature to greatest extent in the base example.This limiting temperature is called " maximum temperature rise " condition, and temperature rise refers to the temperature difference between condenser and the evaporimeter.

In order to determine 1) system pressure 2) temperature 3 of evaporimeter, condenser and generator) the change effect of heat transfer temperature difference, we study parameter.

When generator temperature keep constant and under the maximum temperaturerise condition between evaporimeter and the condenser system pressure change.Along with the rising of system pressure, maximum temperaturerise also strengthens thereupon, as Fig. 3.Next, when the condenser temperature be made as 315K, when evaporator temperature is made as 275K, fixing maximum temperaturerise, research pressure changes Effect on Performance.As shown in Figure 4, pressure raises and causes COP to descend.When system pressure was 5.5bar, the minimum temperature of evaporimeter was 275K.But 315K is far below the maximum temperature 327K of condenser in condenser.When system pressure was 4bar, the maximum temperature of freezing machine/absorber was 315K, but 275K is far above the minimum temperature 266K of evaporimeter.In freezing machine/absorber temperatures is not that the coefficient of performance (is that temperature is low more than the performance height that moves under the maximum temperaturerise condition under the highest situation, the coefficient of performance is high more), but the coefficient of performance improves manyly under the situation that evaporator temperature raises, and please refer to Fig. 5 and 6.

As shown in Figure 5, the temperature (315K) of condenser temperature from basic example is when down reducing, and COP increases gradually, till condensation temperature is near evaporating temperature.Shown in Fig. 3 b, the temperature (266K) in evaporator temperature and the basic example is when up raising, and COP increases gradually, till evaporating temperature is near condensation temperature.This circular flow efficient improved when maximum temperaturerise descended.But, improve evaporator temperature than reducing freezing machine/absorber temperatures and more can improve COP.

In basic example, other parameter is fixed, and the variations in temperature of let us research generator is to Effect on Performance.COP is how along with the variation of generator temperature changes as can be seen from Figure 7.COP reached maximum 0.17 when generator temperature was 373K, but the excursion of COP is very little around best generator temperature.The liquid of coming in when generator temperature raises must be through bigger temperature difference heating.Same, when generator temperature is higher, the also corresponding increase of heat that the bubble pump requires, reason is that the composition of water accounts for manyly in the liquid.But, when generator temperature is low, from water, separate, also do not have the ammonia of return condensed machine/absorber fewer yet.The mutual balance of these several effects during 373K, it is maximum that COP reaches.

Whole three heat transfer temperature differences all are made as 0 in the base example.Change the heat transfer temperature difference value can the reflect heat exchanger performance to the influence of systematic function.Fig. 7 has shown and changes each in three heat transfer temperature differences respectively and change three different-effects that brought simultaneously.Heat transfer temperature difference (2-3) is represented the temperature difference between the

state

2 and 3 in the schematic diagram.

The change of heat transfer temperature difference (2-3) has no impact to COP.Evaporimeter forecooler interior heat mechanical mass flow velocity maximum be ammonia-butane steam air-flow, can cool off the liquefied butane and the gaseous ammonia of coming in.Improve heat transfer temperature difference (2-3) if maintenance heat transfer temperature difference (6-1) is constant, existing ammonia steam temperature necessarily descends, but COP remains unchanged.So the heat transfer temperature difference that plays a decisive role in the forecooler is (6-1).The rising of heat transfer temperature difference (6-1) can reduce COP really, because reduce the ability that the existing temperature of this air-flow has also just reduced to cool off other two strands of liquid stream, air-flow.

The performance of generator inner heat exchanger is also influential to the performance of whole circulation.The heat transfer temperature difference that improves stream 7 and flow between 9 can reduce regeneration (backheat) effect, has also just reduced circulation COP value.The rising of three heat transfer temperature differences also cause the circulating reduction of COP value.But the COP value has also only descended 10% when three heat transfer temperature differences all are 5K.

From low noise kind of refrigeration cycle thermodynamics dynamic property result, can draw following conclusion.At first, evaporimeter has minimum temperature, a freezing machine/absorber that a maximum temperature is arranged under certain system pressure.The maximum temperature of freezing machine/absorber is exactly the saturation temperature of cold-producing medium under this system pressure.The condition of also having determined simultaneously to obtain maximum COP value is a selecting system pressure, leaves the pure cold-producing medium of being almost of freezing machine/absorber under this pressure.In other words, system pressure should be set like this: under the condenser temperature of hope, the operating pressure of freezing machine/absorber is the peak in the possible range.

For the generator temperature of the best of COP existence, it approximately is 100 ℃.But if departed from this optimum temperature, the performance that causes in 60～150 ℃ of scopes descends very little.

We have considered two heat exchangers under study for action, and this is: evaporimeter precooler 1) generator inner heat exchanger 2).The performance of these two heat exchangers is little to the overall performance influence of circulation.Mutually relatively, the performance of evaporimeter forecooler is bigger to the performance impact of circulation.So should be meticulousr during the design forecooler than the inner heat exchanger of design generator.

Circularly exhibiting in the another kind of mode that does not have to finish under the condition of solution pump absorption refrigeration.Compare with Munters ammonia-water-hydrogen diffusion circulation with Platen, the gas diffusion-restricted of this process is littler, and the optional liquid of this process more (can select low-molecular-weight alkane such as iso-butane, propane, different propane as refrigerating fluid for use), can adapt to bigger temperature limit.In addition, hydrogen is not used in this circulation, and hydrogen is difficult to be used, inflammable and explosive again.This circulation is not that unique one (Taylor, 1929) adopt ammonia, water and butane in absorption refrigeration is used, but its structure has disconnected the dissolving ring, so the temperature coupling is more approaching.How COP 0.15 is brought up to 0.20 at present also among research from basic example.

Claims

1, a kind of novel absorption type refrigeration circulating system is characterized in that, adopts one of butane, propane, different propane to make cold-producing medium, selects for use ammonia to make pressure equilibrium agent, and choosing uses water as absorbent.

2, novel absorption type refrigeration circulating system according to claim 1 is characterized in that, comprising:

Evaporimeter is used to place liquefied butane, and is injected with ammonia the liquefied butane partial pressure is reduced;

Heat exchanger is used for providing liquefied butane and reception to come the butane-ammonia gas mixture body of flash-pot and make it to evaporate to evaporimeter;

Condenser, be used to receive the gas that evaporates of flash-pot, and ammonia steam is wherein absorbed by water watered pouring by water after, thereby cause butane partial pressure of vapor rising condensation under higher temperature simultaneously, and the described heat exchanger of process turns back to described evaporimeter

Separator is used for the concentrated ammonia liquor that condenser forms is separated, and isolated ammonia part is entered evaporimeter through over-heat-exchanger, isolated water section is entered condenser water pouring.

3, novel absorption type refrigeration circulating system according to claim 2, it is characterized in that, described separator comprises the heater that preheating is carried out in output to condenser, be used to produce the generator of ammonia and be used for the temporary liquid trap of collecting ammonia-aqueous mixtures, between described generator and described liquid trap, be connected with a bubble pump and be used for rare ammonia-water-soluble liquid pump with generator in described liquid trap, the ammonia steam that described generator produces under the effect of heater is delivered to heat exchanger, described liquid trap bottom has pipeline that water is sent back to described generator, and the aqueous water in the described generator sprays in described condenser by pipeline.

4, novel absorption type refrigeration circulating system according to claim 3 is characterized in that, system pressure is 4 crust.

5, novel absorption type refrigeration circulating system according to claim 3 is characterized in that, the temperature of described condenser is 315K.

6, novel absorption type refrigeration circulating system according to claim 3 is characterized in that, described evaporator temperature is 266K.

7, novel absorption type refrigeration circulating system according to claim 3 is characterized in that, described generator temperature is 375K.

8, novel absorption type refrigeration circulating system according to claim 3 is characterized in that, the liquefied butane in the described condenser by siphon mode through the heat exchanger Returning evaporimeter.

9, novel absorption type refrigeration circulating system according to claim 3 is characterized in that, the temperature of described evaporimeter is-25 ℃ to+40 ℃ scopes.