JPH02106666A - Absorptive type freezer - Google Patents

Abstract

PURPOSE:To provide a fast adjustment of output of a refrigerant capability and prevent entering a super cooling limit by a method wherein a discharging system for a refrigerant pump is provided with a three-way control valve for performing an opening or closing operation of a valve in response to a temperature of cold water port and the three-way control valve controls a spraying system for a spraying nozzle of an evaporator and a bypassing system for a refrigerant tank. CONSTITUTION:Refrigerant discharged from a refrigerant pump 8 distributes its flow rate into a spraying system (a) and a bypassing system (b) by a three- way control valve 10 arranged at a discharging side. Distributing amount at the spraying system (a) and the bypassing system (b) of the three-way control valve 10 is applied for a flow rate control in response to a detected temperature of a temperature sensor 12 arranged at an outlet port of an evaporator of a cold water system 11. With this arrangement, a spraying amount of refrigerant is limited as a cold water temperature is lowered and then a limitation of cooling power is controlled in an internal cycle system without any heat loss.

Description

[Detailed description of the invention] [Industrial application field] TECHNICAL FIELD The present invention relates to an absorption refrigerator, particularly an intermediate stage refrigerator.

The present invention relates to an absorption refrigerator having supercooling prevention means suitable for cooling operation in winter.

[Conventional technology]

Cooling operation in winter is generally low-load, and the chiller cycle and temperature control (hereinafter referred to as temperature control) are set assuming peak times in summer.
A synergistic effect such as a drop in the temperature of the cooling water causes chilled water supercooling, so an automatic refrigerant blower system may be adopted as a countermeasure.

This results in heat loss, which is contrary to energy conservation.

Note that related refrigerators of this type include, for example, Japanese Unexamined Patent Publication No. 80461/1983.

[Problems to be Solved by the Invention] Conventionally, for cold water supercooling, a refrigerant blowing method has been generally implemented in which the cold water outlet temperature is used as a barometer and the refrigerant is blown to the absorber side.

However, this reduces the refrigerating capacity and temporarily increases the cold water outlet temperature. Therefore, since the temperature of the cold water increases, the temperature control command issues a command to increase the wall on the heat source side, thereby increasing the refrigerating capacity. Therefore, the balance with the load side could not be maintained, and the internal heat amount was reflected energy, and due to the unbalanced temperature control, the capacity of the refrigerator became a hunting output, resulting in unstable supply to the load side. .

The present invention was made in order to solve the problems of the prior art described above, and it prevents supercooling of cold water, stabilizes the temperature control balance, prevents internal heat loss, and achieves high efficiency even under low load. The purpose is to provide an absorption chiller that enables energy-saving operation.

[Means to solve the problem]

In order to achieve the above object, a first aspect of the absorption refrigerator of the present invention includes an evaporator and an absorber.

In an absorption refrigerator equipped with a condenser, a regenerator serving as a heat source, a solution heat exchanger, a solution pump, a refrigerant pump, and a piping system that operatively connects these, an evaporator spray is applied to the discharge system of the refrigerant pump. A three-way control valve is provided to control the spray system leading to the nozzle and a bypass system leading to the refrigerant tank, and a temperature sensor is provided in the cold water system communicating with the tube group in the evaporator, and a temperature sensor is provided in the cold water system communicating with the tube group in the evaporator. This is a control circuit that controls the amount of refrigerant sprayed onto the tube group.

Further, the configuration of the second invention includes an evaporator and an absorber.

In an absorption refrigerator equipped with a condenser, a regenerator serving as a heat source, a solution heat exchanger, a solution pump, a refrigerant pump, and a piping system that operatively connects these, the discharge system of the refrigerant pump is provided with a a three-way control valve that controls the amount of refrigerant sprayed onto the tube group of the evaporator in conjunction with the temperature condition of the chilled water in the chilled water system passing through the evaporator; a fuel control valve that controls the amount of heat input; A connected fuel control temperature controller, means for detecting cooling water inlet temperature and cold water mg humidity temperature, and when the cooling water inlet temperature becomes a predetermined temperature or less, the fuel control temperature controller is connected to the fuel control temperature controller in accordance with the temperature drop value. The apparatus is provided with arithmetic control means for outputting a signal for controlling the amount of heat input by converting the controlled cold water temperature of the meter to a higher value.

Additionally, the relationship between the idea behind the development of the present invention and the structure of the invention is as follows.

The present invention deals with two objectives.

To prevent overcooling, it is important not to spray more refrigerant than necessary, and a mechanism is provided to return unnecessary refrigerant to the refrigerant tank and eliminate internal heat loss. As a means for this, a three-way control valve is provided between the refrigerant pump discharge and the evaporator refrigerant spray mechanism, and the system is branched into a spray system and a bypass system that returns to the refrigerant tank.

On the other hand, for the purpose of saving energy during air conditioning operation during the intermediate and winter seasons, the system is equipped with a mechanism that automatically converts adjustments to increase the temperature setting in temperature control.

Since the cooling water temperature drops during the intermediate period, the refrigeration capacity actually increases. In addition, since the load on the load side is significantly reduced compared to the summer, even at the lowest heat input, the output of the refrigerator side is superior, leading to supercooling. therefore,
Is there a way to use the cooling water inlet temperature as a barometer for the temperature control set temperature, and then raise the temperature control set temperature when the coolant inlet temperature drops?
Automatically change the fl adjustment set temperature. As a result, it is possible to provide a margin with respect to the supercooling trip limit, and the amount of heat input is controlled to match the output of the refrigerating capacity based on the cooling water inlet temperature, leading to energy savings.

[Effect]

The condensed refrigerant and residual refrigerant from the refrigerant sprayed in the evaporator tube group collects in the refrigerant tank and is circulated again to the refrigerant spray, but the refrigerant pump discharge system has a valve that opens and closes depending on the chilled water outlet temperature. A three-way control valve will be installed. When the chilled water outlet temperature is higher than the set temperature, this three-way control valve proportionally increases the amount of circulation to the refrigerant spray system as the temperature difference increases, thereby outputting the refrigerating capacity.

Similarly, if the temperature is lower than the set temperature, reduce the amount sent to the spray system and increase the amount returned directly to the refrigerant tank.

By adjusting the circulation amount in this way, it is possible to adjust the output of the refrigerating capacity at an early stage, and it is possible to prevent the refrigerating capacity from reaching the supercooling limit.

Further, overcooling caused by increasing the refrigerating capacity with low cooling water can be prevented by changing the temperature control operation.

The amount of heat input is controlled by a control valve that controls the amount of fuel inflow or combustion based on the temperature of the cold water. Therefore, the guideline for the output of the refrigeration capacity is the difference between the chilled water outlet temperature and the inlet temperature, but since control is generally performed to keep the chilled water outlet temperature constant, the chilled water inlet temperature is decreasing. In this case, a temperature control conversion is performed to increase the set temperature of the chilled water temperature of the fuel control temperature controller by the temperature difference corresponding to the temperature drop with respect to the predetermined reference coolant inlet temperature. In this operation, a microcomputer with arithmetic functions changes the fuel control output signal and performs an operation to quickly control the amount of heat input in advance.

As a result, overcooling prevention and energy saving are achieved.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 is a cycle system diagram showing the configuration of a direct-fired absorption type dual-effect water cooler/heater according to an embodiment of the present invention, and FIG. It is a cycle system diagram showing the composition of a heavy-duty water cooler/heater.

First, the first invention will be explained with reference to FIG.

In FIG. 1, 1 is an evaporator, 2 is an absorber, 3 is a condenser, 4 is a high temperature regenerator, 5 is a low temperature regenerator, 6 is a solution heat exchanger, 7 is a solution pump, 8 is a refrigerant pump, and 9 is the refrigerant tank,
10 is a three-way control valve provided in the discharge piping system of the refrigerant pump 8, and the three-way control valve 0 is connected to a spray system (■) that leads to the spray nozzle 1a of the evaporator 1, and a bypass system (■) that leads to the refrigerant recovery tank 9. The discharge side (2) of the refrigerant pump 8 is branched. 11 is a cold water system that communicates with the tube group 11, a in the evaporator 1; 12 is a temperature sensor provided on the evaporator outlet side of the cold water system 11; 13 is a three-way valve controller; This is a cooling water system that passes through the condenser 3.

The cold water in the cold water system 11 passes through the tube group 11a of the evaporator 1 and becomes cold water at 7°C. The refrigerant in the lower part of the evaporator 1 is sprayed from the upper spray of the evaporator 1, that is, the spray nozzle 1a, to the evaporator tube group 11a by the refrigerant pump 8, and is evaporated by obtaining heat from the cold water. The evaporated refrigerant is
It enters the absorber 2 and is absorbed by the solution sprayed from the top of the absorber 2. The solution that has absorbed the refrigerant is sent to the low-temperature regenerator 5 and the high-temperature regenerator 4 by the solution pump 7 through the solution heat exchanger 6 . In each regenerator, the solution is heated to evaporate the refrigerant in the solution, and the refrigerant vapor enters the condenser 3 and is cooled and condensed by the cooling water system 19.

All of the refrigerant condensed in the condenser 3 returns to the evaporator 1 and collects in a refrigerant tank 9 provided at the bottom of the evaporator 1. The returned refrigerant is sent to the tube group 1 of the evaporator 1 again by the refrigerant pump 8.
It is pumped to spray onto 1a. Here, the flow rate of the refrigerant discharged from the refrigerant pump 8 is distributed to the spray system (1) and the bypass system (2) by a three-way control valve 10 provided on the discharge side. The distribution amount on the ■ side and ■ side of the three-way control valve 10 is determined by the temperature sensor 1 installed on the evaporator outlet side of the chilled water system 11.
Based on the temperature detected in step 2, the three-way valve controller 13 sends a valve opening command signal to the three-way control valve 10 to control the flow rate. As a result, the amount of refrigerant spray is limited as the chilled water temperature decreases, and the cooling capacity is controlled by an internal cycle system without causing heat loss.

On the other hand, the temperature control set temperature is changed depending on the cooling water inlet temperature,
An embodiment of the second invention in which the temperature control temperature setting zone is automatically changed to the upper limit side will be described with reference to FIG. 2.

In FIG. 2, the same reference numerals as those in FIG. 1 are the same parts as in the previous embodiment, so a description thereof will be omitted.

In FIG. 2, 14 is a fuel control valve, 15 is a fuel control temperature controller electrically connected to this fuel control valve 14, and 16 is a temperature controller for fuel control.
1 is a chilled water temperature control sensor provided on the evaporator 1 side of the chilled water system 11, 17 is a chilled water temperature detector, 18 is a computing unit for computing control means equipped with a microcomputer, etc., and 20 is a sensor for cooling water system 19. Cooling jobs provided [1 temperature sensor, 21 is a cooling water temperature detector.

Heat input to the water cooler/heater is controlled by the fuel control valve 14, and a signal output to the fuel control valve 14 is output from the fuel control temperature controller 15. The output of this fuel control temperature controller 15 is performed as follows.

A signal detected by a chilled water temperature control sensor 16 provided in the chilled water system 11 is outputted by a chilled water temperature detector 17, and the signal is inputted to a computing unit 18. In the calculator 18, when the coolant temperature input signal is lower than the set temperature, the deviation temperature from the set temperature is replaced with the refrigeration cycle efficiency improvement value, the capacity amplifier is calculated, and the chilled water outlet temperature is converted to the chilled water outlet temperature. The chilled water temperature input from the detector 17 is shifted by the deviation amount, replaced as an input signal of the fuel control temperature controller 15, and output.

As a result, the amount of heat input is controlled so that the minimum required amount of human heat is burned as fuel.

This embodiment provides the following effects.

1) Overcooling failures caused by sudden temperature changes can be avoided.

2) Overcooling failures in low cooling water operation can be avoided.

3) Energy-saving operation has become possible by adding the cooling water inlet temperature condition to the conventional cold water temperature control.

4) Stable continuous operation can be performed.

Next, Figures 3 and 4 show the chilled water temperature time proportional control.
This will be explained with reference to the figures.

FIG. 3 is a diagram showing the time proportional control start/stop region, and FIG. 4 is a diagram showing changes in cold water temperature.

The direct-fired absorption type double-effect chiller/heater shown in Figure 2 above automatically changes the set temperature according to the change in chilled water temperature over time.
It is possible to perform energy-saving operation commensurate with the load condition.

In Figure 3, the horizontal axis shows the elapsed time (minutes) from the time when the chilled water outlet temperature decreased to 12℃ or less, and the vertical axis shows the set stop temperature ('C), and the time proportional control is activated. Stop area (O
(N area, OFF area).

During cooling, the automatic stop operation temperature is set to 3 depending on the elapsed time since the cold water outlet temperature has decreased to 12℃ or less.
Automatically change as shown. That is, if the cold water temperature is 10
If it reaches 11 °C in ~20 minutes, stop the heat input at 11 °C, and if it reaches 10 °C in 20 to 30 minutes, 10 °C.
Stop heat input at °C. However, for 10 minutes, regardless of the load, it will not stop until the temperature reaches 7°C.

If this is expressed as the relationship between cold water temperature and time, with time on the horizontal axis and cold water temperature on the vertical axis, it will be as shown in Part 4.

As described above, in one aspect of the present invention, the setting value of the temperature sensor for controlling the cold water outlet temperature is converted in accordance with the passage of time. In other words, if the chilled water outlet temperature decreases and the time from passing a certain temperature (e.g. 12°C) to passing through the next temperature (e.g. 11°C) is short, the temperature will be higher than the initial setting value (7°C). It is equipped with a control device for an automatic conversion control mechanism that stops burner combustion and, if the time is long, stops burner combustion at an initial setting value.

In addition, during heating, the automatic stop operation temperature can be similarly changed depending on the elapsed time from the time when the hot water outlet temperature becomes 55° C. or higher.

〔Effect of the invention〕

As described above, according to the present invention, supercooling of cold water is prevented, temperature control balance is stabilized, internal heat loss is prevented,
It is possible to provide an absorption chiller that enables efficient energy-saving operation even under low load.

[Brief explanation of drawings]

FIG. 1 is a cycle system diagram showing the configuration of a direct-fired absorption type dual-effect water cooler/heater according to an embodiment of the present invention, and FIG. FIG. 3 is a cycle diagram showing the configuration of a heavy-duty water cooler/heater, FIG. 3 is a line diagram showing time proportional control start/stop regions, and FIG. 4 is a line diagram showing changes in chilled water temperature. 1... Evaporator, 2... Absorber, 3... Condenser, 4
...High temperature regenerator, 5...Low temperature regenerator, 6...Solution heat exchanger, 7...Solution pump, 8...Refrigerant pump, 9
... Refrigerant tank, 10 ... Three-way control valve, 11 ... Chilled water system, 12 ... Temperature sensor, 13 ... Three-way valve controller, 14 ... Fuel control valve, 15 Temperature control for fuel control total,
16... Chilled water temperature sensor, 17... Chilled water temperature detector, 18... Arithmetic unit, 19... Cooling water system, 20...
...Cooling water inlet temperature sensor 21...Cooling water temperature detector.

Claims (1)

[Claims] 1. Absorption refrigeration equipped with an evaporator, an absorber, a condenser, a regenerator serving as a heat source, a solution heat exchanger, a solution pump, a refrigerant pump, and a piping system that operatively connects these. On the machine,
A three-way control valve is provided in the discharge system of the refrigerant pump to control a spray system leading to the evaporator spray nozzle and a bypass system leading to the refrigerant tank, and a temperature sensor is provided in the cold water system communicating with the tube group in the evaporator. An absorption refrigerator comprising: a control circuit that controls the amount of refrigerant sprayed onto the tube group of the evaporator in communication with the chilled water temperature condition. 2. In an absorption refrigerator equipped with an evaporator, an absorber, a condenser, a regenerator serving as a heat source, a solution heat exchanger, a solution pump, a refrigerant pump, and a piping system that operatively connects these, the refrigerant pump a three-way control valve that controls the amount of refrigerant sprayed onto the tube group of the evaporator in conjunction with the temperature condition of the chilled water in the chilled water system passing through the evaporator; and a fuel control valve that controls the amount of heat input. A fuel control temperature controller electrically connected to the fuel control valve; a means for detecting the cooling water inlet temperature and the chilled water temperature control temperature; an absorption refrigerating machine, characterized in that it is provided with arithmetic control means for outputting a signal for controlling the amount of heat input by converting the controlled cold water temperature of the fuel control temperature controller to a higher value in accordance with the above.