JPH064554U - Cooling system - Google Patents

Abstract

(57) [Abstract] [Purpose] For a cooling system that needs to change its cooling capacity, use a motor-compressor unit with a single rated power and piston displacement to operate it at optimum maximum efficiency. With the goal. The power supply unit supplies a variable voltage and frequency to the electric motor, as a function of the data provided by the sensor means of the temperature change related to the reference expected temperature,
Electronic control connected to temperature sensor means located at one or more points in the range to be cooled and temperature sensor means located on the surface of the condenser for monitoring the power supply unit The power supply control unit is controlled by a unit.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cooling machine having a motor-compressor unit with a variable amount of supplied electricity, and more particularly to a device for giving different electric power supply states to the motor-compressor unit according to required performance.

[0002]

[Background of device]

 The object of the present invention is characterized by rated powers that are substantially adjacent to each other, such as 1 / 12HP, 1 / 10HP, 1 / 8HP, 1 / 6HP, etc., for cooling systems that require varying cooling capacities. Instead of having a range of motor-compressor units, it is to use a motor-compressor unit with a single rated power and piston displacement. In the case of motor-compressor units for refrigeration systems, it is known that their cooling capacity is proportional to the speed of rotation of the motor and thus the frequency supplied.

With such a configuration, it is possible to reduce the number of ratings of the motor / compressor unit, so that the facility is simplified, especially in mass production of the cooling device, and the storage unit, the spare unit, and the like are reduced. This has the advantage of simplifying the structure and further increasing the value by providing an automatic control device for electrically feeding the motor so that the cooling system can be operated at optimum maximum efficiency in the manner described in the embodiments. is there.

The technical problem to be solved in order to achieve the above-mentioned objects was to design a suitable electronic control system and connect it to the cooling system. In the known cooling system, the motor / compressor unit is operated intermittently in order to maintain the temperature of the volume to be cooled near the temperature value selected by the user. For this reason, a bimetal type thermostat is used as a temperature control means, and by this, the motor is turned on and off at two temperatures above and below the temperature selected by the user.

However, in these thermostats, since the temperature change (Δt) in the volume to be cooled, that is, the temperature change in the condenser or the evaporator occurs due to the intermittent operation of the temperature control means, the heat of the cooling system is reduced. The mechanical efficiency cannot be increased.

Further, as the number of times the electric motor is turned on and off increases, it is common that the overall efficiency of the electric motor decreases.

[0007]

[Means for Solving the Problems]

 Efficiency can be surely increased by solving the above-mentioned technical problems. To that end, the cooling device according to the invention provides that the power supply unit supplies a variable voltage and frequency to the electric motor, as a function of the data provided by the sensor means of the temperature change related to the reference expected temperature. An electronic control connected to temperature sensor means located at one or more points in the range to be cooled and temperature sensor means located on the surface of the condenser for monitoring the power supply unit The power supply unit is controlled by the unit.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows diagrammatically a cooling system, 10 a cabinet, which, as usual, has an evaporator 12 and a condenser 14 and is a piston-type motor-compressor driven by a single-phase induction motor. It is connected to the circuit comprising unit 16. The temperature sensor 18 is provided in the cabinet 10 and the temperature sensors 20 and 22 are provided in the evaporator 12 and the condenser 14 so that the temperature value at the monitoring point is continuously and accurately given. These temperature sensors are connected to a central control unit 24, which is an electronic control unit equipped with a microprocessor, which processes the temperature data obtained from the sensors 18, 20, 22 and gives the power supply unit 26 a suitable signal. It sends a signal of voltage V and frequency F to the motor compressor unit 16 in response to the signal received from the central control unit 24. Regarding the voltage V and frequency F supplied to this motor, there is a standard that the ratio V / F is constant. Under such supply conditions, the rated power of the motor changes in proportion to the frequency, and its operating characteristics are practically unchanged.

Since temperature changes can occur in the cabinet and at three points in the evaporator and condenser, three temperature sensors 18, 20 and 22 are placed in the cabinet and on the surface of the evaporator 12 and condenser 14, respectively. Has been. When the refrigerator door is opened, the temperature value of the evaporator 12 changes and the voltage V and the frequency F are supplied to the motor / compressor unit 16 The power supply unit 26 is connected to the central control unit 24 The sensor 20 sends a signal. When the cabinet door is opened, the temperature value in the cabinet changes and the sensor 18 sends a signal to the central control unit 24. When the temperature of the condenser 14 changes, the sensor 22 sends a signal to the central controller 24. Thus, three temperature sensor means 18, 20 and 22 are placed at specific points where the temperature can change.

The cooling capacity required for the motor-compressor unit, and thus the motor supply conditions, determines the temperature value determined by the sensor 18 in the central control unit 24 as a function of the temperature change over time in the volume to be cooled. The performance of the cooling system is automatically adapted by determining and performing the process so as to determine the required temperature condition of the cooling system according to these values.

In order to increase the thermodynamic efficiency of the cooling system, the temperature values obtained from the three temperature sensors 18, 20, 22 are processed by the central control unit 24 and the control signal is supplied to the power supply unit 26. Then, the temperature change (Δt) at the monitor point is set to the minimum value.

Furthermore, focusing on the fact that it is advantageous to evaporate at the maximum possible temperature, in order to get the closest to the theoretical efficiency of the cooling system, the temperature data obtained from the sensors 20 and 22 are stored in the central controller 24. Can be further processed to determine further control of the power supply conditions.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating an embodiment of the present invention.

[Explanation of symbols]

 10 Cabinet 12 Evaporator 14 Attenuator 16 Motor-compressor unit 18, 20, 22 Temperature sensor 24 Central controller 26 Power supply unit

Claims (4)

[Scope of utility model registration request] 1. A cooling device comprising a motor-compressor unit (16) equipped with an electric motor, and an evaporator (12) and a condenser (14) connected to the motor-compressor unit (16). A power supply unit (26) supplies a variable voltage (V) and frequency (F) to the electric motor, and a sensor means for detecting a temperature change (Δt) related to a reference planned temperature.
Temperature sensors placed at one or more points in the range (10) to be cooled in order to monitor the power supply unit (26) as a function of the data given by (18, 20, 22) Means that the power supply unit (26) is controlled by an electronic control unit (24) connected to the means (18, 20) and the temperature sensor means (22) located on the surface of the condenser (14). Characteristic cooling device. 2. A motor-compressor unit having a single rated power and piston displacement, the motor-compressor unit operating with different performance characteristics corresponding to multiple rated powers around its rated power. The cooling device according to claim 1, wherein the cooling device is configured as described above. 3. The cooling device according to claim 1, wherein the electronic control unit comprises a microprocessor. 4. The power supply unit comprises an inverter and a voltage regulator.
The cooling device described.