JPS61235652A - Method of controlling absorption refrigerator - 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 [Field of Industrial Application] The present invention relates to a control method for an absorption chiller in which the temperature of chilled water is controlled by adjusting the heating amount of a generator.

[Conventional technology]

Generally, in an absorption refrigerator, the amount of heating by the generator is adjusted so that the temperature of the chilled water is approximately constant.

If the temperature of the cooling water rises by 1 due to a failure or operational error in the cooling fan of the cooling tower during operation of the refrigerator, the temperature of the solution in the absorber increases, which affects the absorption action and shifts the concentration of the solution toward higher concentrations. If this is shown in FIG. 1, what appears as a solid line during normal operation will change in the direction of the broken line as the solution concentration increases, and eventually it will approach the crystal line K and there is a danger of crystallization.

Conventional crystallization prevention methods include a method of detecting a high concentration and mixing a refrigerant into the solution if there is a risk of crystallization (for example, Japanese Patent Publication No. 17338/1983).

[Problem that the invention seeks to solve]

However, this method has a problem in that the refrigerant produced by adding heat to the generator is emitted unnecessarily without exerting its freezing effect, which is contrary to energy conservation.

An object of the present invention is to provide a method for controlling an absorption refrigerating machine that can solve the problem described in item 1 of the conventional method, prevent the danger of crystallization of the solution, and prevent wasteful consumption of energy. This is the purpose.

[Means for solving problems]

The present invention, as a means for solving the above problems,
It is equipped with an absorber, a generator, a condenser, an evaporator, and a solution path and a refrigerant path that connect these devices, and detects the temperature of the cold water and adjusts the amount of solution heating in the generator based on the detected value to adjust the temperature of the cold water. In a method for controlling an absorption refrigerator, a cascade control is performed in which the temperature of a solution in an absorber is detected and a chilled water temperature set value is adjusted according to the detected solution temperature, and the cascade control Until reaches a predetermined value, the cold water temperature set value is kept constant unless another control B is performed, and when the detected solution temperature exceeds a predetermined value, the higher the detected solution temperature is, the higher the detected solution temperature is. It is an object of the present invention to provide a method for controlling an absorption refrigerator, characterized in that the chilled water temperature set value is increased.

〔Example〕

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

In Figure 2, A is an absorber, G is a generator, C is a condenser,
E is evaporator, X is solution heat exchanger, sp is solution pump, R
P is a refrigerant pump. Piping 1゜2.3.4 is a solution pipe,
5 is an overflow pipe, and pipes 6 and 7 are refrigerant pipes. 8
．． 9 is a cooling water pipe, 10 is a cold water pipe, 11 is a heating pipe,
It is equipped with a flow control valve 12 that controls the flow rate of a heating medium such as steam to adjust the amount of solution heating.

A control mechanism 13 controls the flow rate control valve 12 in accordance with the cold water outlet temperature detected by the temperature detector 14, and maintains the cold water outlet temperature at a predetermined set value unless other control is performed.

Reference numeral 15 denotes a temperature detector that detects the temperature of the solution in the absorber A, and performs cascade control to change the cold water temperature set value in the control mechanism 13 according to the detected solution temperature.

Changes to the set value should be made by keeping the chilled water temperature set value constant until the detected solution temperature in the absorber reaches a predetermined value (approximately 39°C at N') unless other controls are performed. When the solution temperature exceeds a predetermined value, the higher the detected solution temperature, the higher the cold water temperature setting value is changed. If the temperature of the detection solution further increases, a dangerous state such as crystallization will occur, so in order to avoid this, a second predetermined value (I) is set above the first predetermined value of the temperature of the detection solution. 45° C.), and when this second predetermined value is reached, the operation of the refrigerator is stopped, for example, the supply of heat source to the generator is stopped.

If the cooling water temperature rises due to an operational error or failure of the cooling fan, the solution temperature will rise, and if the chilled water temperature remains constant, the refrigerant vapor pressure will also remain constant, and the solution concentration will become thicker and approach the crystal line.

If the chilled water temperature set value is increased here, the refrigerant evaporation temperature of the evaporator E increases while the solution temperature remains substantially constant. Therefore, the solution concentration is reduced, and the cycle moves from a solid line to a broken line as shown in FIG. In this way, by increasing the chilled water temperature set value, the cycle moves towards lower concentration, which can be used to avoid mixing the refrigerant liquid into the solution and avoid crystals while allowing operation for as long as possible. can.

Crystals are basically formed by increasing the concentration.

Therefore, the solution temperature of absorber A (the temperature at any one point within the range of the output of solution heat exchanger X for concentrated solutions and the inlet of solution heat exchanger X for dilute solutions) is detected, and this temperature is detected. When the temperature rises above a predetermined value, the set value of the cold water temperature is increased.

For more precise control, it is preferable to detect the concentration in addition to the temperature of the solution and change the cold water temperature set value in accordance with both side-out values.

The concentration may be detected directly or indirectly, for example, by detecting the refrigerant liquid level in the evaporator E with the water level detector 16. The detected solution concentration signal detected by the water level detector 16 is sent to the control mechanism 13, and together with the detected solution temperature signal from the temperature detector 15, the chilled water temperature set value is changed to a value obtained by a predetermined program and cascade is performed. Control.

In addition to the control of the present invention, cascade control as shown in Japanese Patent Application No. 57-222118 is used to detect when the detected solution temperature is below a third predetermined value, which is lower than the first predetermined value. Control may also be used in which the cold water temperature setting value is increased as the solution temperature is lower.

Note that the above method can be used for single-effect and multiple-effect absorption refrigerators and cold/hot water machines.

〔Effect of the invention〕

The present invention is useful in cases where the cooling water temperature rises and there is a risk of solution crystallization when the cooling fan, cooling pump, etc. of the cooling tower malfunctions during operation of the refrigerator, or when an operational error occurs. On the other hand, by detecting the solution temperature and increasing the cold water temperature in response to a rise in temperature above a predetermined value, the cycle approaching the crystal line is moved to a lower concentration direction.
It is possible to operate for a long period of time while avoiding crystallization without taking measures such as mixing a refrigerant liquid into the solution, and has the effect of preventing wasteful consumption of energy.

[Brief explanation of drawings]

FIG. 1 is a cycle diagram of a conventional method, FIG. 2 is a flow diagram of an embodiment of the present invention, and FIG. 3 is a cycle diagram thereof. 1, 2. 3. 4... Piping, 5... Overflow pipe, 6.7... Piping, 8.9... Cooling water pipe, 1
0...Cold water pipe, 11...Heating pipe, 12...Flow rate control valve, 13...Control mechanism, 14.15...Temperature detector, 16...Water level detector, A...・Absorber, G...
Generator, C... Condenser, E... Evaporator, X... Solution heat exchanger, sp... Solution pump, RP... Refrigerant pump. Patent applicant: EBARA CORPORATION Representative Patent Attorney: Masayuki Takagi Representative Patent Attorney: Yakushi Minoru Representative Patent Attorney: Yori 1) Takaji
Section 71-- Nori Gei

Claims (1)

[Claims] 1. An absorber, a generator, a condenser, an evaporator, and a solution path and a refrigerant path connecting these devices, detect the cold water temperature, and use the detected value to heat the solution in the generator. In a control method for an absorption chiller that controls the temperature of chilled water by adjusting the amount, the temperature of a solution in an absorber is detected, and a cascade control is performed in which a set value of the chilled water temperature is adjusted according to the detected solution temperature, A method for controlling an absorption refrigerator, wherein the cascade control is such that when the detected solution temperature exceeds a predetermined value, the higher the detected solution temperature is, the higher the chilled water temperature set value is. 2. A second predetermined value is set above the predetermined value of the detected solution temperature, and the refrigerator is stopped when the detected solution temperature exceeds the second predetermined value. The method described in Scope 1.