JP2005127614A - Adsorption type refrigerating machine and its operating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adsorption type refrigerating machine and an adsorbent used in the same, capable of reducing the regenerating energy without enlarging the equipment, and improving the energy efficiency by increasing the refrigerating capacity. <P>SOLUTION: In this adsorption type refrigerating machine composed of an evaporator for evaporating a refrigerant, an adsorber filled with the adsorbent for adsorbing the evaporated refrigerant and comprising a heating means and a cooling means for the adsorbent, and a condenser for condensing the refrigerant desorbed from the adsorber, water is used as the refrigerant, the adsorbent satisfying that a relative pressure (P/P<SB>0</SB>) is 0.14-0.2, and an adsorption swing amount is changed to be more than 0.05 kg/adsorbent (1kg) is filled, and the adsorption swinging operation and the desorbing operation are performed in an area of the adsorption of 0.04 kg/adsorbent (1kg) or more. As the adsorbing/desorbing operation is performed in an area of capillary condensation, the heat of adsorption is inhibited, the heating quantity necessary for regeneration is reduced, and the freezing capacity and the energy efficiency can be improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an adsorption refrigeration machine having an increased refrigeration capacity by a pressure swing method, an operation method thereof, and an adsorbent used for the adsorption refrigeration machine.

  An adsorption heat pump is a device that pumps heat by using the phase change that accompanies the adsorption and desorption phenomenon of working medium (refrigerant) such as water or alcohol to a solid adsorbent such as silica gel or activated carbon. is there. FIG. 1 shows an example in which this adsorption heat pump is used as an adsorption refrigerator, and an evaporator 1 for evaporating refrigerant and two adsorbers filled with a solid adsorbent such as silica gel, that is, an adsorption tower. 2 and 3, and a condenser 4, the inside of these apparatus systems is sealed under reduced pressure, and the adsorption towers 2 and 3 are adsorption towers that adsorb refrigerant vapor, that is, water vapor when water is used as a refrigerant. The regenerator for desorbing the adsorbed moisture (water vapor), that is, the regenerator is used by alternately switching the regenerator every predetermined operation time. As shown in FIG. 1, when the adsorption tower 2 is used as an adsorber and the adsorption tower 3 is used as a regenerator, that is, the valves V1, V4, V5, V6, V11, and V12 are open. When the filled valves V2, V3, V7, V8, V9, and V10 are closed, hot water of about 55 to 75 ° C. flows through the heat exchanger 5 of the adsorption tower 3 on the regenerator side. The solid adsorbent is heated to desorb moisture previously adsorbed. This desorbed water vapor moves through the valve V4 to the condenser 4 provided with a heat exchange pipe through which the cooling water cooled to, for example, about 30 to 37 ° C. by the cooling tower 6 passes. And it cools and condenses by the said heat exchange pipe in the condenser 4, Condensed water is cooled by the cooling tower 6, and moves to the evaporator 1 via the condensed water piping which abbreviate | omitted illustration. When the water in the evaporator falls on the heat exchange pipe through which the cold water in the evaporator 1 passes, the water in the evaporator boiles and evaporates, and the cold water in the heat exchange pipe is rapidly removed by the heat of vaporization at this time. Decreases. On the other hand, the water vapor evaporated in the evaporator 1 flows into the adsorption tower 2 through the valve V1, and is supplied to the cooling tower 6 from the cooling tower 6 through the valve V3. While the heat of adsorption is removed, it is adsorbed on the adsorbent. If the valves are switched so that the filled valves V2, V3, V7, V8, V9, V10 are open and the valves V1, V4, V5, V6, V11, V12 are closed, the adsorption tower 2 is used as a regenerator. The adsorption tower 3 is used as an adsorber. Thereafter, this cycle is basically repeated. A cycle considering the cooling / preheating process is also performed so that the water vapor pressure in the adsorber and the regenerator can be easily adsorbed or regenerated at the start of adsorption or regeneration. In this way, cold water whose temperature has dropped rapidly can be supplied to the outside from the heat exchange pipe passing through the evaporator 1. The heat exchangers 5 and 5a include, for example, a fin type in which cooling water or hot water flow paths and adsorbent packed layers are alternately stacked, and the adsorbent is filled into the fin space in a required amount.

In the adsorption refrigeration machine, water having no environmental load can be used as a refrigerant without the disadvantages of facilities such as an increase in the size of a compressor and an increase in compression ratio as in a conventional compression heat pump. In general, in adsorption refrigerators that use phase changes associated with adsorption and desorption phenomena, the adsorption characteristics of the adsorbent are determined by the combination with the working medium, i.e., the refrigerant. As a material, silica gel is usually suitable. This silica gel-water type adsorption refrigerator can be driven only by a heat source such as exhaust heat of 100 ° C. or less, but the adsorption amount difference cannot be made large, and thus the cold output is limited. Even in the case of a heat source of 100 ° C. or lower, if the temperature of exhaust heat increases, in the adsorption process using an adsorber regenerated with this heat source, a low relative pressure (P / P ₀ ) (P: Adsorption is performed in the state of water vapor partial pressure, P ₀ : saturated water vapor pressure at 7 ° C.), so that the adsorbate, that is, the water of the refrigerant is adsorbed directly on the inner surface of the pores. The binding energy is greater than when adsorbed by capillary condensation. For this reason, the amount of heat required for desorption and the amount of heat of adsorption at the time of adsorption are increased, and the heat transfer area of the heat exchanger in the adsorber must be increased accordingly, leading to an increase in equipment size and a decrease in energy efficiency. .

  On the other hand, as an adsorption refrigeration machine with sufficient refrigerating capacity with a small amount of regenerative heat and improved energy efficiency (coefficient of performance), air conditioning consisting of two adsorbers arranged in series and one heat exchanger An adsorption refrigeration machine is disclosed in which two lines are provided so that continuous cooling is possible (see, for example, Patent Document 1). In this adsorption type refrigerator, the air conditioning air dehumidified and heated by the two adsorbers of one air conditioning line is cooled in a constant humidity by the heat exchanger, and then the other air conditioning in the desorption process It is humidified and cooled by one adsorber on the line and sent to the air-conditioned space. By this humidification cooling, the one adsorber can be desorbed without supplying heat energy from the outside, and there is an advantage that the amount of heat required for regeneration can be reduced with respect to the obtained refrigeration capacity.

JP 2001-91090 A ([0019] to [0032])

  However, the silica gel-water type adsorption refrigerator has the above-mentioned problems, and the adsorption refrigerator disclosed in Patent Document 1 capable of reducing the necessary regeneration energy has sufficient refrigeration capacity. In addition, it is necessary to arrange a plurality of adsorbers in one air conditioning line, that is, the adsorption process, which causes problems such as an increase in the size of equipment.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an adsorption refrigeration machine and an adsorbent used therefor that reduce regeneration energy, increase refrigeration capacity, and improve energy efficiency without increasing the size of equipment. It is.

  In order to solve the above problems, the present invention employs the following configuration.

That is, it comprises an evaporator for evaporating the refrigerant, an adsorber filled with an adsorbent and provided with an adsorbent heating means and a cooling means, respectively, and a condenser for condensing the refrigerant desorbed from the adsorber. The adsorber is cooled by the cooling means to adsorb the refrigerant vapor from the evaporator, the other adsorber is heated by the heating means to regenerate the adsorbent, and the adsorber is alternately adsorbed and regenerated. In an adsorption refrigeration machine used as a storage device, an adsorbent in which the refrigerant is water and the relative swing (P / P ₀ ) is between 0.14 and 0.20 and the amount of adsorption swing changes by 0.05 kg / adsorbent (1 kg) or more. It was filled. Here, the relative pressure (P / P ₀ ) is the ratio of the saturated water vapor pressure P at the atmospheric temperature in the evaporator to the saturated water vapor pressure P _{0 at the} surface temperature of the adsorbent filled in the adsorber. The atmospheric temperature in the evaporator is assumed to be 7 ° C.

If the above-mentioned narrow relative pressure (P / P ₀ ) is 0.14 to 0.20 and the adsorption swing amount changes by 0.05 kg / adsorbent (1 kg) or more, that is, an ideal adsorbent is filled, this low and narrow relative By performing the adsorption operation with a pressure swing between the pressures, the generated heat of adsorption can be suppressed, so the flow rate of the cooling water in the adsorber, that is, the adsorbent packed bed during adsorption can be reduced, and the temperature is relatively low. It is possible to easily desorb the moisture adsorbed by the heat source using the exhaust heat.

The reason why the relative pressure (P / P ₀ ) is limited to the range of 0.14 to 0.20 and the adsorption swing amount is limited to 0.05 kg / adsorbent (1 kg) or more will be described below. In order to obtain a cooling temperature of 7 to 12 ° C. in the adsorption refrigerator, the adsorbent temperature at the time of adsorption depends on the cooling water temperature of the adsorber 30 to 35 ° C., and the relative pressure at the time of adsorption (P / P ₀ ) has a maximum of 0.2. On the other hand, if the relative pressure (P / P ₀ ) is made smaller than 0.14 in order to improve the amount of adsorption swing, it is necessary to make the adsorbent at a higher temperature during regeneration, increasing the sensible heat loss in the device, In addition, the binding energy at the time of adsorption increases due to the high degree of drying of the adsorbent. For this reason, the amount of heat required for desorption and the amount of heat of adsorption during adsorption increase, and the heat transfer area of the heat exchanger in the adsorber needs to be increased. In addition, if the adsorption swing amount is changed to 0.05 kg / adsorbent (1 kg) or more, the refrigerating capacity can be remarkably improved as compared with the case where ordinary silica gel is used as the adsorbent. When the swing amount is smaller than 0.05 kg / adsorbent (1 kg), the effect of improving the refrigerating capacity is reduced.

  Thus, using the pressure swing method for the adsorption operation, the adsorbent whose starting adsorption amount changes by 0.04 kg / adsorbent (1 kg) and the adsorption swing amount by 0.05 kg / adsorbent (1 kg) or more between the above low relative pressures. Is reduced, the heat of adsorption generated is suppressed, and less energy is required for desorption, and the refrigerating capacity and energy efficiency can be remarkably improved as compared with the case of using ordinary silica gel as the adsorbent.

2, when filled ideal adsorbent A _f described above and the conventional silica gel A _s the adsorption type refrigerator, for each of the adsorption isotherm, a relative pressure performing adsorption swing operation (P / P ₀ ) In comparison with the adsorption swing amount Δq. Table 1 shows the operating conditions of this adsorption refrigerator. The adsorption isotherm of the ideal adsorbent _Af is based on theoretical calculation, and the pore structure is preferably uniform, that is, highly regular. Moreover, the adsorber temperature line on silica gel A _s is based on the measured value at 25 ° C..

From FIG. 2, the adsorption amount is 0.095 to 0.180 kg when the ideal adsorbent _Af is filled by performing the adsorption operation at the ideal swing position where the relative pressure (P / P ₀ ) falls within the range of 0.14 to 0.20. / Adsorption swing amount in the high adsorption amount region of the adsorbent (kg) is realized, and a high adsorption amount of 0.085 kg / adsorbent (1 kg) is obtained. In contrast, when filled with silica gel A _s is the adsorption swing range is 0.075～0.080Kg / obtained only low adsorption amount of the adsorbent 0.005 kg / adsorbent in (1kg) (1kg).

Table 2 is the cooling capacity of the adsorption refrigerator filled with ideal adsorbent A _f, shown in comparison with a case filled with conventional silica gel A _s. It can be seen that the refrigerating capacity can be increased by about 9 times by filling the ideal adsorbent _Af when the adsorbent filling amount is similar.

  Desirably, the heating means uses exhaust heat in a temperature range of 50 to 200 ° C. as a heat source, and the cooling means uses cooling water in a temperature range of 30 to 40 ° C. obtained by a cooling tower as a cooling heat source.

An adsorbent having the performance of changing the adsorption swing amount by 0.05 kg / adsorbent (1 kg) or more when the relative pressure (P / P ₀ ) is between 0.14 and 0.20 is used for exhaust steam and exhaust from the factory in the above temperature range. Desorption using hot water as a heat source is possible, and because the heat of adsorption in the adsorption process is suppressed, the heat of adsorption is removed with cooling water in the above temperature range normally obtained by a cooling tower, and the inside of the adsorber is required. Can be kept below temperature.

  In the above operation method of the adsorption refrigeration machine, it is desirable to perform the adsorption swing operation and the desorption operation in the region where the adsorption amount of the adsorbent filled in the adsorber is 0.04 kg / adsorbent (1 kg) or more.

Thus, in the region where the pore structure of the adsorbent has high regularity and the adsorption amount is 0.04 kg / adsorbent (1 kg), most of the inner surface of the pore of the adsorbent is adsorbate, That is, it is in a state covered with the coolant water. If the adsorption swing operation is performed from this state, adsorption and desorption are performed in the region of capillary condensation, and at the time of adsorption and desorption, less heat is required for cooling and heating, and adsorption refrigeration with lower energy is required. The machine can be operated and energy efficiency is improved. Here, the lower limit of the adsorption amount is 0.04 kg / adsorbent (1 kg) because the adsorption swing amount is 0.05 kg / adsorbent (P / P ₀ ) between 0.14 and 0.20. For adsorbents that change by 1 kg) or more, starting the adsorption swing operation in an adsorption amount range of 0.04 kg / adsorbent (1 kg) or more can increase the amount of adsorption, improving the refrigeration capacity. By performing an adsorption swing operation in an adsorption area of kg / adsorbent (1 kg) or more, the required desorption can be performed regardless of the temperature in the temperature range of the above-mentioned heat source (50 to 200 ° C.), and the refrigerating capacity can be improved. This is because it does not decrease.

The start and end timing of the suction swing operation, based premeasured adsorption isotherm of the adsorbent, the measured value of the ambient temperature of the temperature and the evaporator of the adsorptive material A _P filled in the adsorber Can be controlled.

An adsorbent for an adsorption refrigerator using water as a refrigerant, wherein the adsorbent has a highly regular pore structure and a ratio of at least 3 × 10 ⁵ m ² / adsorbent (1 kg) or more. It is desirable to have a surface area and a performance of an adsorption amount swing amount of 0.05 kg / adsorbent (1 kg) or more in a relative pressure (P / P ₀ ) range of 0.14 to 0.20.

If the specific surface area of the adsorbent is smaller than 3 × 10 ⁵ m ² / adsorbent (1 kg), an adsorption swing amount of 0.05 g / adsorbent (1 g) or more cannot be obtained. The upper limit of the specific surface area is preferably about 15 × 10 ⁵ m ² / adsorbent (1 kg). If the specific surface area becomes too large, there will be a portion where the pore surface of the adsorbent is not covered with refrigerant water at the operating relative pressure, and when the adsorption swing operation is started from this state, the refrigerant water is directly adsorbed on the adsorbent. In this state, the binding energy is larger than that in the case of being adsorbed by capillary condensation, so that the heat of adsorption at the time of adsorption and the heating amount required for desorption are increased, and the energy efficiency is lowered. As mentioned above, if the adsorption amount at the start of adsorption is 0.04kg / adsorbent (1kg) or more in the relative pressure (P / P ₀ ) range of 0.14 to 0.20, the generated adsorption heat is suppressed. In addition, less energy is required for desorption, and the refrigerating capacity and energy efficiency can be remarkably improved as compared with the case of using ordinary silica gel.

Examples of the material for realizing the ideal adsorbent _Af having the structure and the adsorption characteristics include highly ordered silica and zeolite whose pore structure is adjusted to 2 nm or less in the production process.

In the present invention, an adsorption type refrigerator is filled with an adsorbent having a performance in which the amount of adsorption swing varies by 0.05 g / adsorbent (1 g) or more in the range of low relative pressure (P / P ₀ ) 0.14 to 0.20. Therefore, the generated heat of adsorption is suppressed, less energy is required for desorption, and the refrigerating capacity and energy efficiency can be remarkably improved.

  In addition, by operating the adsorption refrigerator so as to start the adsorption swing operation in the region where the adsorption amount is 0.04 kg / adsorbent (1 kg) or more, the adsorption and desorption operations are performed using most of the capillary condensation region. Therefore, less heat is required for cooling and heating during adsorption and desorption, which contributes to improvement in refrigeration capacity and energy efficiency. And since the amount of heat required for heating at the time of desorption is smaller, the refrigerating capacity is not affected by the temperature of the heat source.

  Furthermore, the adsorption refrigerator can be desorbed by using normal exhaust steam or exhaust hot water from a factory as a heat source, and cooling water in a temperature range obtained by a normal cooling tower can be used to remove adsorption heat. Since it can be used, it does not require a special installation environment and can be operated easily.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. Note that the device configuration of the adsorption refrigerator embodiments, except novel adsorbent A _P embodiments filled in the adsorption tower 2 (see FIG. 1), similarly to the adsorption refrigerating machine shown in FIG. 1 It is.

Figure 3 were measured at 25 ° C., shows the adsorption isotherms of the novel adsorbent A _p embodiments, the novel adsorbent A _p is the two surfactants double-chain type as the template Used mesoporous silica produced by a hydrothermal synthesis method. In the range of operation relative pressure (P / P ₀ ) 0.14 to 0.20 of the adsorption refrigerator from the end of regeneration to the end of adsorption, 0.05 kg in the region where the adsorption amount is 0.04 kg / adsorbent (1 kg) or more / It can be seen that the adsorption swing amount Δq of the adsorbent (1 kg) is realized.

FIG. 4 shows an adsorption-type refrigerator filled with the above-mentioned new adsorbent A _p and normal adsorbent A _s (silica gel) using a pressure swing method in a relative pressure (P / P ₀ ) range of 0.14 to 0.20. operation, i.e., when the adsorption operation, a comparison of the adsorbed amount Δq for adsorption time, as the adsorption time, it can be seen that towards the adsorption capacity of the novel adsorbent a _p is superior to silica gel.

FIG. 5 shows the daytime cold energy during operation of the adsorption refrigerator in the range of 0.14 to 0.20 relative pressure (P / P ₀ ) filled with a new adsorbent A _p and a normal adsorbent A _s (silica gel). This is a comparison of the adsorption amount Δq with respect to the adsorption time when the supply temperature of the cold water from the evaporator 1 (see FIG. 1) fluctuates in the range of 7 to 14 ° C. due to the change in output. it is seen that the newer adsorbent a _p is superior about 8-21% than silica gel.

FIG. 6 shows the temperature of the heat source during operation of the adsorption refrigerator in the range of 0.14 to 0.20 relative pressure (P / P ₀ ) filled with a new adsorbent A _p and a normal adsorbent A _s (silica gel). when regeneration temperature is changed by variation shows an example of comparison of the adsorbed amount Δq for the regeneration temperature of the novel adsorbent a _p and the normal of the adsorbent a _s (silica gel), the newer adsorbent a _p It can be seen that the average adsorption amount, that is, the adsorption capacity, is superior to that of silica gel.

7, similarly, during the operation of the new adsorbents A _p and the normal of the adsorbent A _s adsorption chillers in the range of relative pressure (P / P ₀₎ 0.14 to 0.20 of the (silica gel) packed respectively, adsorption This is a comparison of the cooling output with time. High cold output newer adsorbent A _p is compared to the silica gel, cold output of the peak is better about 14%.

  As described above, the adsorption refrigerator is filled with an adsorbent whose adsorption swing amount changes by 0.05 kg / adsorbent (1 kg) or more between the low relative pressures, and the adsorption operation is performed using the pressure swing method. Compared to conventional adsorbents such as packing, the amount of adsorption increases, refrigerating capacity is remarkably improved, and the amount of heating required for regeneration can be reduced, improving the energy efficiency of the refrigerator. .

  The adsorption refrigeration machine of the present invention can improve the refrigeration capacity and energy efficiency by the adsorption operation using the pressure swing method if it is filled with the required adsorbent, and is stable to the process cooling process in the industrial field. It can be used as a low-cost cold water supply source.

It is explanatory drawing of an adsorption-type refrigerator. It is an explanatory view showing the relationship between the range and the adsorption swing amount Δq of relative pressure performing adsorption swing operation of an adsorption type refrigerating machine (P / P _0). It is explanatory drawing of the adsorption isotherm of a novel adsorbent ( _Ap ). It is explanatory drawing which compared the adsorption amount with respect to adsorption time with a novel adsorbent ( _Ap ) and the conventional silica gel. It is explanatory drawing which compared the adsorption amount with respect to evaporator temperature same as the above. It is explanatory drawing which compared the adsorption amount with respect to the regeneration temperature of a novel adsorbent ( _Ap ) and the conventional silica gel. It is explanatory drawing which compared the cold-power output of the adsorption-type refrigerator of embodiment filled with the novel adsorbent ( _Ap ), and the adsorption-type refrigerator filled with silica gel.

Explanation of symbols

1: Evaporator 2, 3: Adsorption tower 4: Condenser 5, 5a: Heat exchanger 6: Cooling tower

Claims (4)

One adsorber is composed of an evaporator for evaporating the refrigerant, an adsorber filled with an adsorbent, each having an adsorbent heating means and a cooling means, and a condenser for condensing the refrigerant desorbed from the adsorber. The adsorber is cooled by the cooling means to adsorb the refrigerant vapor from the evaporator, the other adsorber is heated by the heating means to regenerate the adsorbent, and the adsorber is alternately used as an adsorber and a regenerator. In the adsorption refrigerator used, the refrigerant is water and filled with an adsorbent whose relative pressure (P / P ₀ ) is between 0.14 and 0.20 and the amount of adsorption swing changes by 0.05 kg / adsorbent (1 kg) or more. The adsorption type refrigerator characterized by this. The heating means uses exhaust heat in a temperature range of 50 to 200 ° C as a heat source, and the cooling means uses cooling water in a temperature range of 30 to 40 ° C obtained by a cooling tower as a cold heat source. The adsorption-type refrigerator as described. The operation method of the adsorption type refrigerator according to claim 1, wherein the adsorption swing operation and the desorption operation are performed in an area where the adsorption amount of the adsorbent filled in the adsorber is 0.04 kg / adsorbent (1 kg) or more. A method of operating an adsorption refrigeration machine. An adsorbent for an adsorption-type refrigerator using water as a refrigerant, wherein the adsorbent has a highly regular pore structure and a ratio of at least 3 × 10 ⁵ m ² / adsorbent (1 kg) or more. An adsorbent for an adsorption refrigeration machine having a surface area and having an adsorption amount swing amount of 0.05 kg / adsorbent (1 kg) or more in a relative pressure range of 0.14 to 0.20.