JPH0221498B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for preventing freezing of a refrigerant used in an absorption heat pump.

Absorption heat pumps are composed of a regenerator, a condenser, an evaporator, an absorber, etc. The regenerator separates the refrigerant from the absorption liquid, and the evaporator vaporizes the liquid refrigerant, converting the heat obtained to condensation heat or absorption. It has a mechanism that extracts the reaction heat of the liquid to the outside of the machine, and is used to raise the temperature of hot spring water and factory waste water.

However, in general, this type of absorption heat pump uses lithium bromide or
Since water is used as a refrigerant, there is a risk that the refrigerant (water) may freeze depending on the usage conditions of the absorption heat pump. When the refrigerant freezes, the so-called heat pump function may be completely lost. There was a drawback that the equipment could be damaged.

For this reason, when the temperature or pressure conditions of the absorption heat pump's evaporator approach conditions that would cause the refrigerant to freeze, a refrigerant freeze prevention device is installed that forcibly stops the operation of the absorption heat pump, such as by stopping the operation of the burner of the regenerator. Attempts have also been made to install an attached heat pump, but when an absorption heat pump is installed in a location that is susceptible to the influence of outside air temperature, stops operation in the winter, and starts operation after the equipment has been exposed to low temperatures, Even when there is no risk of the refrigerant freezing, the refrigerant antifreeze device may operate and make it impossible to restart the heat pump operation.

Particularly when the temperature sensing part for preventing refrigerant freezing is installed in the evaporator of an absorption heat pump, the ability to prevent the refrigerant from freezing is high, but if the temperature inside the evaporator drops even for a short time after restarting operation, the refrigerant will be prevented from freezing. It is difficult to prevent the device from operating, and it has the disadvantage that normal operation cannot be achieved unless the burner is forced to operate separately to raise the temperature inside the machine, or the temperature of the device is raised by running hot water manually. Ta.

The present invention was developed in view of these points, and for a certain period of time after the absorption heat pump starts operating, the function of stopping the operation of the absorption heat pump by the anti-freezing device does not extend to the operation of the heat pump, thereby making it possible to start the operation of the absorption heat pump smoothly. This is a control device characterized by:

In the figure, 1 is a regenerator having a heater 2 for separating the refrigerant from the dilute absorption liquid that has absorbed the refrigerant;
3 is a refrigerant gas separator; 4 is a condenser that provides the latent heat and sensible heat of the gas refrigerant flowing from the separator 3 to the heat exchanger 5 to liquefy the refrigerant; 6 is the condenser 4;
An evaporator obtains thermal energy from heat source water 7 with a low temperature level by vaporizing the liquefied refrigerant under low pressure conditions; 8 is a pump that recirculates the unvaporized liquid refrigerant above the evaporator 6; 9 is a liquid pump; This is an absorber that absorbs the refrigerant vaporized in the evaporator 6 using the absorption liquid supplied from the regenerator 1. A heater 10 is housed therein to raise the temperature of hot water flowing into the chamber, and the heater 10 and the heat exchanger 5 are connected to obtain hot water from a pipe 11 through which it flows.

In addition, 12 is an absorption liquid pump that returns the dilute absorption liquid that has absorbed the refrigerant to the regenerator 1, 13 is a burner, 14 is a refrigerant low-temperature thermostat that forms an anti-freeze device, and 15 is an absorption liquid pump that returns the dilute absorption liquid that has absorbed the refrigerant to a constant temperature (for example, 50°C or higher). ) is a pump start/stop thermostat that operates to drive the absorption liquid pump 12, and 16 is a heat source water thermostat that closes when the heat source water temperature is above a certain temperature to enable heat pump operation, and these control devices. are connected as shown in the electric circuit of FIG. 2 or 3 to constitute the control device of the present invention.

That is, in the electric circuit shown in FIG. 2, operation switch 1 is turned on to start the operation of the absorption heat pump.
7, normally the heat source water temperature is above a certain temperature and the heat source water thermostat 16 is closed, the solenoid 18 is energized and the contacts 19 and 20 are closed,
Since the burner 13 is energized via the normally closed switch contact 21, it starts heating the absorption liquid in the regenerator 1 regardless of whether the contact of the refrigerant low temperature thermostat 14 is opened or closed. As mentioned above, the refrigerant low temperature thermostat 14 turns the burner 1 on when the temperature or pressure conditions of the evaporator 6 approach conditions that would cause the refrigerant to freeze.
3, the operation of the absorption liquid pump 12 is stopped, but if such an electric circuit is used, the stop function of the anti-freeze device will not reach the absorption heat pump due to the contact 21, and the burner 13 will be forcibly stopped. Driving takes place.

In this way, the temperature of the absorption liquid in the regenerator 1 rises next, and when the contact 15 of the absorption liquid pump thermostat is closed and the absorption liquid pump 12 is operated, the absorption liquid 9
The high temperature absorption liquid is circulated and normal heat pump operation is started. Furthermore, since the closing of the contact 15 also energizes the solenoid 22, the contact 21 is opened, and the low temperature thermostat 14 for preventing refrigerant freezing also enters the normal operating state at the same time as the normal heat pump operation starts. In such operating conditions, if there is a risk of refrigerant freezing due to a decrease in the flow rate of the heat source water, the antifreeze device automatically stops the burner 13 and then stops the operation of the absorption liquid pump 12 to prevent damage to the heat pump. can be prevented.

FIG. 3 shows another embodiment of the control device of the present invention, in which the stop mechanism of the refrigerant antifreeze device does not reach the heat pump for a certain period of time at the start of operation, and the burner 13 is forced to operate. Therefore, the timer solenoid 23 and its contact 24 are connected in parallel with the refrigerant low temperature thermostat 14. The other parts are the same as in FIG. 2, so while the operation switch 17 is turned on and the timer switch 23 and contacts 24 are working, the absorption heat pump is operated in the same way as at the start of operation in FIG. At the same time as the timer 23 finishes operating and the contact 24 opens, the refrigerant low temperature thermostat 1
The refrigerant anti-freeze device containing No. 4 now functions as a normal protection device.

As described above, the absorption heat pump control device according to the present invention prevents the operation stop function of the refrigerant antifreeze device from reaching the heat pump for a certain period of time after the absorption heat pump starts operating. This system is designed to prevent the stoppage of heat pump operation due to malfunction of the refrigerant antifreeze mechanism, which tends to occur when the heat pump starts operating. Operation can be started, and it can be applied to a small and simple absorption heat pump to ensure a reliable start of operation.

[Brief explanation of drawings]

FIG. 1 is a cycle diagram showing an example of an absorption heat pump, and FIGS. 2 and 3 are main part electrical circuit diagrams showing an embodiment of a control device according to the present invention. 1... Regenerator, 4... Condenser, 6... Evaporator,
9...Absorber, 10...Heater, 14...Refrigerant low temperature thermostat.

Claims (1)

[Claims] 1. A regenerator that separates the refrigerant from the dilute absorption liquid that has absorbed the refrigerant, an evaporator that obtains thermal energy from a heat source fluid with a low temperature level by vaporizing the liquid refrigerant under low pressure conditions, and an evaporator that absorbs the refrigerant that has been vaporized by the evaporator. In an absorption heat pump having an absorber that absorbs liquid, and a heater disposed in the absorber to heat the fluid using the latent heat of refrigerant gas and the heat of reaction between the refrigerant gas and the absorption liquid, the inside of the evaporator is An anti-freeze device is provided that forcibly stops the operation of the absorption heat pump when the refrigerant freeze condition approaches, and for a certain period of time after the absorption heat pump starts operating, the anti-freeze device has a function to stop the operation of the absorption heat pump. An absorption heat pump control device characterized in that the function of the absorption heat pump is not exceeded.