JP3172315B2 - Number of operation units for absorption chillers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling the number of operation of a multi-type absorption refrigerator in which a plurality of absorption refrigerators are installed in parallel in order to enhance the capacity.

[0002]

2. Description of the Related Art As this kind of technology, for example, Japanese Patent Publication No. Sho 6
There is a technique disclosed in Japanese Patent Application Laid-Open No. 2-62266 for determining the number of operating absorption chillers in response to a change in load on the secondary side.
However, this control method is simply intended to respond to changes in the secondary load in a stable state, and even if there is an absorption refrigerator whose capacity has been reduced due to the generation of non-condensable gas, etc. Without consideration, the system adopts a method of selecting and starting the smallest absorption chiller from among the absorption chillers that can respond to the secondary load from the design capability.

[0003]

For this reason, if an absorption chiller having a reduced capacity is selected and operated, the fuel is consumed excessively and energy efficiency is reduced. The solution of this point has been an issue.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and is an apparatus for switching and controlling the number of operating absorption chillers installed in parallel according to the load amount. A means for detecting the difference between the inlet and outlet temperature of the cold or hot water of each absorption refrigerator, and the means for detecting the difference between the inlet and outlet temperature of each absorption refrigerator and the opening of the fuel valve for each absorption refrigerator. Means for comparing and calculating the design temperature difference of the entrance and exit of the absorption chiller, wherein the operation order of the absorption chillers whose comparison calculated value does not reach the predetermined value is positioned at the lower rank. .

[0005]

[Operation] A comparison is made between the difference between the inlet and outlet temperature of cold water or hot water detected for each absorption refrigerator and the design temperature difference between the inlet and outlet of cold water or hot water determined by the opening of the fuel valve of each absorption refrigerator. If there is an absorption chiller that does not reach the predetermined value, the operation order of this absorption chiller is set to the lower rank and it corresponds to the secondary load, so that the capacity of the absorption chiller is reduced by generating non-condensable gas inside the machine. The frequency of operation of the reduced absorption refrigerator is reduced, fuel consumption is saved, and the coefficient of performance is improved.

[0006]

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. In FIG. 1, reference numerals 1 to 4 denote absorption chillers installed in parallel, each of which is obtained from a conventionally known absorber, evaporator, condenser, generator, heat exchanger (all not shown), and the like. For example, the pump 5 can circulate and supply cold water or hot water (hereinafter, referred to as cold water) to an air conditioner 6 of a building. 7 is a control device that determines the magnitude of the load of the air conditioner 6 from the temperature of the chilled water detected by the temperature detecting means T1 and the secondary side set temperature, and controls the number of operating the absorption chillers 1-4. It is connected to the control unit of each absorption chiller via a communication line. Note that T2 to T9 are absorption chillers 1-4.
These are temperature detecting means installed at each of the cold water inlet / outlet portions, and can transmit measured temperature data to the control device 7 via the communication line.

Each of the absorption chillers 1 to 4 controls the opening of a fuel valve (not shown) for controlling the supply of fuel to the regenerator according to the magnitude of the load, similarly to the conventionally known absorption chillers. The thermal power can be controlled by the control. When each device is operating normally, if the fuel valve is of a proportional control type, the inlet / outlet temperature difference ΔT of the chilled water for each opening degree is the inlet / outlet design temperature difference in FIG. It is uniquely determined like A (may differ between absorption chillers 1-4).

[0009] However, when air enters through a pipe connection part or the like in a low pressure designed machine or when a hydrogen gas or the like is generated due to a reaction between a refrigerant or an absorbing liquid and a metal of the machine, these gases are normally used. Since this is a non-condensable gas that does not condense in the refrigeration cycle, the internal pressure rises and the evaporation of the refrigerant is hindered, so that a predetermined temperature difference between the inlet and outlet temperature difference ΔT of the cold water cannot be obtained.

[0010] In the absorption refrigerator in such a state,
In order to obtain a predetermined chilled water temperature difference, an operation in which the opening degree of the fuel valve is made larger is performed, and the coefficient of performance decreases, so that fuel such as gas is wasted.

For each of the absorption chillers 1 to 4, the temperature difference ratio k (ΔT / A) of the chilled water inlet / outlet temperature difference ΔT of each absorption chiller actually detected by the temperature detecting means T2 to T9 to the inlet / outlet design temperature difference A. ) Is a predetermined ratio, for example, a limit temperature difference ratio B indicated by a broken line defined as 0.8 as shown in FIG.
At the following times, the control device 7 determines that the refrigeration capacity of the absorption chiller is reduced, and when operating the absorption chillers 1 to 4 corresponding to the load, The absorption chiller, which is operated with the operation order being set lower, and whose refrigeration capacity is reduced, is controlled by the control device 7.
Is displayed on the abnormality display section 71 of the display device using a liquid crystal or the like.

For example, as illustrated in FIG. 3, the absorption chillers 1, 2, and 4 are sequentially started to perform a chilled water supply operation in order to cope with a change in load. When the difference ratio k is calculated to be, for example, 0.78, and it is determined that the refrigerating capacity is decreasing, the control device 7 outputs a stop signal to the absorption refrigerator 2 to stop the operation, and instead, the absorption refrigeration is performed. A start signal is output to the machine 3 to start this operation.

Further, the fact that the capacity of the absorption chiller 2 is reduced is displayed on the abnormality display section 71 from time a, and an alarm is issued.

When the load further increases at time b, the control unit 7 outputs an operation signal to the stopped absorption chiller 2 to start it. Further, when the load decreases until time c, the operation stop signal is preferentially output from the control device 7 to the absorption chiller 2 whose refrigeration capacity has decreased, and the absorption chiller is stopped.

As described above, according to the control device 7 of the present invention, the inlet / outlet design temperature difference A of the chilled water uniquely determined for each load (opening of the fuel valve) for each of the absorption chillers 1-4.
And a temperature difference ratio k between the actual temperature difference ΔT of the inlet and outlet of the chilled water detected by the temperature detecting means T2 to T8,
Judging the state of each refrigeration capacity, if there is an absorption chiller with reduced capacity, it is operated with the operation order of the lower rank, so the absorption chiller with reduced refrigeration capacity due to generation of non-condensable gas etc. Driving time is shortened, and the overall coefficient of performance is improved.

Since the present invention is not limited to the above embodiment, various modifications can be made without departing from the spirit of the appended claims.

For example, the critical temperature difference ratio B with respect to a predetermined entrance / exit design temperature difference A is set to an appropriate ratio (for example, 0.7 to 0.
9), the temperature difference ΔT actually detected by the temperature detecting means T2 to T9 is subtracted from the value of the limit temperature difference ratio B. When this value is positive, the refrigerating capacity is not significantly deteriorated.
It is also possible to provide such that it is determined that the refrigerating capacity is degraded when the value is negative.

Further, when there are a plurality of absorption chillers whose values obtained by the comparison operation do not reach the predetermined value, the absorption chillers which are farther from the predetermined value are positioned lower and operated.

Further, the temperature detecting means T3.
It can be replaced with a single temperature detecting means installed at an appropriate position on the outlet side of the air conditioner 6.

Furthermore, the absorption chillers installed in parallel may have the same or different refrigeration capacities, and the fuel valves may be of a control system other than proportional control. .

[0021]

As described above, the absorption chiller according to the present invention is a device for switching and controlling the number of operating absorption chillers installed in parallel according to the load amount. Means for detecting the difference between the inlet and outlet temperatures of the hot water, and the means for comparing and calculating the difference between the inlet and outlet temperatures of each absorption refrigerator detected by this means and the design temperature difference between the inlet and outlet of the cold water or hot water determined by the opening of the fuel valve for each absorption refrigerator. Means, and the operation number control device of the absorption chiller is characterized in that the operation order of the absorption chiller in which the value calculated and compared does not reach the predetermined value is positioned at the lower rank,

The frequency of operation of an absorption refrigerator having a reduced capacity due to generation of non-condensable gas in the machine is reduced, fuel consumption is reduced, and the coefficient of performance is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment.

FIG. 2 is an explanatory diagram of a method for detecting an absorption refrigerator having insufficient capacity.

FIG. 3 is an explanatory diagram of a control example.

[Explanation of symbols]

 1-4 Absorption refrigerator 5 Pump 6 Air conditioner 7 Controller 71 Abnormality display section T1-T9 Temperature detecting means A Design temperature difference between entrance and exit B Limit temperature difference ratio

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 15/00 306 F25B 15/00

Claims (1)

(57) [Claims] 1. An apparatus for switching and controlling the number of operating absorption refrigerators installed in parallel according to a load amount,
Means for detecting the temperature difference between the inlet and outlet of the cold or hot water of each absorption refrigerator; and the inlet and outlet of the cold or hot water determined by the difference between the temperature of the inlet and outlet of each absorption refrigerator detected by this means and the opening of the fuel valve for each absorption refrigerator. Means for comparing and calculating a design temperature difference, wherein the operation number control apparatus of the absorption chillers is characterized in that the operation order of the absorption chillers whose comparison calculated values do not reach a predetermined value is positioned lower.