JPS6238629B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solar dynamic air conditioner that drives a refrigeration cycle circuit using a Rankine cycle circuit using solar heat as a heat source.

An object of the present invention is to improve the efficiency of a Rankine cycle circuit and the overall efficiency of an air conditioner, as well as to improve the reliability of an expander in a Rankine cycle circuit.

Conventionally, Rankine cycle air conditioners that use solar heat as a heat source use a circulation pump to flow a heat medium from a solar heat collection circuit to an evaporator of the Rankine cycle circuit.

In the conventional example described above, the flow rate of the heat medium circulation pump is constant. As is well known, the amount of solar heat absorbed into the solar heat collector circuit is constantly changing, so the amount of heat input to the boiler of the Rankine cycle circuit changes. Therefore, in some cases, the working fluid at the inlet of the expander in the Rankine cycle circuit becomes an unevaporated two-phase flow and flows out the internal lubricating oil of the expander, increasing the amount of internal leakage of the expander and causing damage to the expansion mechanism. This accelerated wear.

The present invention eliminates the drawbacks of the conventional examples and provides a highly efficient solar air conditioner. DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. 1 and 2 of the accompanying drawings.

As shown in FIG. 1, the solar dynamic air conditioner is formed of a solar heat collection circuit, a Rankine cycle circuit, and a refrigeration cycle circuit. A solar heat collection circuit that absorbs and transports solar heat is composed of a heat medium transport pipe 1, a circulation pump 2, and an evaporator 3 (hereinafter referred to as a boiler) having a multi-tube structure or the like. As the heat medium, for example, an ethylene glycol aqueous solution is used. The Rankine cycle circuit includes a boiler 3, an expander 4, a condenser 5, and a working fluid pump 6 arranged in a ring shape. For example, a fluorocarbon compound is used as the working fluid. The refrigeration cycle circuit is
A compressor 7, a condenser 8, an expansion valve 9, and an evaporator 10 are arranged in a ring.

In the boiler 3, the working fluid to which the solar heat has been transferred evaporates and becomes high-temperature, high-pressure steam that flows into the expander 4, which acts on a rotating part (for example, a rotary vane) of the expander 4 to perform an expansion process. and transmits power to its rotating shaft 11. The rotating shaft 11 is the compressor 7
The power is transmitted to the refrigeration cycle, and the refrigerant in the refrigeration cycle produces a refrigeration effect to cool the inside of the house.

When the solar heat of the heat medium conveyed by the solar heat collection circuit decreases during operation, the amount of heating to the working fluid in the boiler 3 decreases, and the temperature of the expander 4 in FIG. 2 (showing the state of the working fluid in the Rankine cycle) decreases. The state of the working fluid at the inlet changes from a vapor state A to a two-phase flow state B of liquid and vapor. At this time, expander 4
A detector 12 installed at the inlet of the working fluid detects the void ratio of the working fluid (quantity used to evaluate the ratio of vapor and liquid in a two-phase fluid).
is detected, it is determined that the liquid working fluid has started to enter the inlet of the expander 4, and the rotation speed of the circulation pump 2 of the solar heat collection circuit is increased via an appropriate control circuit 13.

The detector 12 is a device that detects the ratio of gas (steam) and liquid in the fluid, and therefore a generally commercially available void ratio measuring device may be used. Void rate is 100% when the fluid is only gas
It is called.

The rotation speed of the circulation pump 2 is adjusted, the amount of heat medium circulated is increased, the amount of heating to the boiler 3 is improved, and the working fluid at the inlet of the expander 4 is brought into the two-phase state B in FIG.
The state returns to steam state A, and normal operation is achieved.

By detecting the void ratio of the working fluid at the inlet of the expander 4, increasing the amount of heating to the boiler 3, and preventing liquid working fluid from entering the expander 4, the expansion efficiency is improved. Wear of the expander 4 can be prevented, and when the expander 4 is of a positive displacement type (for example, a sliding vane type), the expansion efficiency is greatly affected by the leakage of working fluid inside the expander 4. According to the present invention, it is possible to prevent the lubricating oil from washing away, which causes this problem, and as a result,
The expansion efficiency is maintained high, thus improving the overall efficiency of the air conditioner, the lubricating oil is not washed away, and the sliding parts inside the expander 4 are protected by an oil film to prevent wear. In addition to increasing the reliability of the system, it can also be applied to turbine-type expanders, in which case it can prevent damage to the turbine blades due to the intrusion of liquid working fluid and also prevent abnormal vibrations. It is.

As described above, according to the present invention, the ratio of gas and liquid in the working fluid to the inlet of the expander of the Rankine cycle circuit can be detected using the detector that detects the void ratio. The circulation pump of the solar heat collection circuit can be controlled and the rotation speed can be adjusted using the output of This increases the amount of heating and allows normal operation, and also provides excellent effects such as improving expansion efficiency and preventing wear on the expander.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of a solar dynamic air conditioner according to an embodiment of the present invention, and FIG. 2 is a pressure-enthalpy diagram of a working fluid. DESCRIPTION OF SYMBOLS 1... Conveyance pipe, 2... Circulation pump, 3... Evaporator, 4... Expander, 5... Condenser, 6... Working fluid pump, 7... Compressor, 8... Condenser, 9 ……
Expansion valve, 10... Evaporator, 12... Detector, 13
...control circuit.

Claims (1)

[Claims] 1. A solar heat collection circuit that circulates a heat medium heated by solar heat in a conveying pipe by a circulation pump, an evaporator, an expander, a condenser, and a working fluid pump that heat a working fluid by the heat medium, arranged in a ring. A refrigeration circuit including a connected Rankine cycle circuit, a compressor rotated by power transmitted from the expander, a condenser, an expansion valve, and an evaporator connected in a ring, and a working fluid inlet of the expander. A solar dynamic air conditioner, comprising: a detector for detecting the ratio of gas to liquid in a working fluid; and a control means for controlling rotation of the circulation pump based on the output of the detector.