COMPRESSOR-FREE REFRIGERATION SYSTEM POWERED BY HEAT SOURCE

A refrigeration system having: a heat source that provides heat energy; a power generator that contains the heat source to heat a refrigerating medium, to increase the temperature and pressure and vaporize the refrigerating medium; a condenser into which flows the liquid refrigerating medium from the power generator under the pressure difference resulted from heating in the power generator, and in which the liquid refrigerating medium temperature is decreased; a throttle valve that jets the liquid refrigerating medium into an evaporator to decrease its pressure and absorb heat; an evaporator to exchange heat from the refrigerating medium with a refrigeration output; and a liquid working medium return unit through which the liquid working medium accumulated on the bottom of the evaporator flows by gravity back freely to the power generator, wherein the evaporator, liquid working medium return unit, and power generator are arranged from top to bottom vertically.

DETAILED DESCRIPTION OF THE EMBODIMENTS

As shown inFIG. 1, the refrigeration system in the present invention comprises: a heat source1that is designed to provide heat energy; a power generator2that contains a liquid working medium3and a gaseous working medium4, a condenser5, a throttle valve7, an evaporator8, a refrigeration output10, and a liquid working medium return unit15. The power generator2utilizes the heat source1arranged in it to heat up the refrigerating medium comprising the liquid working medium3and gaseous working medium4, so that the temperature and pressure of the refrigerating medium are increased and the refrigerating medium is vaporized. Under the action of the pressure difference resulted from the high temperature in the power generator2, the liquid refrigerating medium3flows from the power generator2into the condenser, and the temperature of the liquid refrigerating medium is decreased in the condenser5. The throttle valve7controls the liquid refrigerating medium flowing through the condenser to jet out from it under the action of the pressure difference, so that the pressure of the liquid refrigerating medium is decreased under the jet action and the liquid refrigerating medium absorbs heat. The low-temperature and low-pressure refrigerating medium is jetted from the throttle valve7into the evaporator8, exchanges heat with the refrigeration output10in the evaporator, and is accumulated in a form of liquid refrigerating medium on the bottom of the evaporator8. The liquid working medium accumulated on the bottom of the evaporator8flows back freely to the power generator under gravity action via the liquid working medium return unit15.

The liquid working medium return unit15comprises an upper valve12, a reservoir13, and a lower valve14, wherein, the upper end of the reservoir13is connected to the evaporator8via the upper valve12, the lower end of the reservoir13is connected to the power generator2via the lower valve14, and the upper valve12and lower valve14open sequentially, but don't open at the same time. Especially, the evaporator8, liquid working medium return unit15, and power generator2are arranged from top to bottom in a vertical direction in turn.

The working process of the entire system is as follows: the liquid working medium3is heated up in the power generator2, so that the temperature and pressure of the liquid working medium3are increased and the liquid working medium3is vaporized. In the entire system, the evaporator side is in low-temperature and low-pressure state, while the power generator side is in high-temperature and high-pressure state. For example, the temperature is 20° C. at the evaporator side and 60° C. at the power generator side. It is seen from the following table: in the case of refrigerant F-12, the pressure at 20° C. is 0.4689 MPa and 1.427 MPa at 60° C., which is to say, the pressure difference between the evaporator side and the power generator side is 0.958 MPa.

Under the action of the pressure difference between the evaporator side and the power generator side, the liquid working medium that is not vaporized in the lower part of the power generator flows out of the power generator2into the condenser5through a pipe outlet below the gas-liquid interface in the power generator2. At the condenser5, the temperature of the liquid working medium drops, but the liquid working medium is still in high-pressure state. The high-pressure liquid working medium is jetted out through a throttle valve into the evaporator8. At this point, the pressure of the liquid working medium drops, and the liquid working medium is vaporized and absorbs the heat from the refrigeration output in the evaporator; thus, heat exchange is accomplished.

To prevent reduction of pressure difference between the power generator and the evaporator and ensure the working medium can flow back to the power generator and circulates, a liquid working medium return unit15is arranged between the power generator and the evaporator.

The liquid working medium return unit15comprises an upper valve12(e.g., in the form of an electronic switch), a reservoir13, and a lower valve14(e.g., in the form of an electronic switch). The upper end of the reservoir13is connected to the evaporator8via the upper valve12, and the lower end of the reservoir13is connected to the power generator2via the lower valve14.

Especially, the evaporator8, liquid working medium return unit15, and power generator2are arranged from top to bottom in a vertical direction in turn.

After heat exchange with the refrigeration output10, the gaseous working medium in the evaporator becomes low-temperature and low-pressure liquid working medium. The liquid working medium is accumulated on the bottom of the evaporator. The upper valve12connected to the bottom of the evaporator8opens at a specific time interval. Within a preset time after the upper valve is opened, the pressure between the reservoir13and the evaporator8will be balanced, and the liquid working medium on the bottom of the reservoir13will flow back freely into the reservoir13under gravity action, as shown inFIG. 2. Then, the upper valve12is closed. Next, the lower valve14is opened; within a preset time after the lower valve14is opened, the pressure between the reservoir13and the power generator2will be balanced, and the liquid working medium in the reservoir13will flow back freely into the power generator2under gravity action in the same way. Then, the lower valve14is closed. As the upper valve and lower valve are opened in alternate, pressure isolation is achieved between the power generator and the evaporator. With the liquid working medium return unit15, the pressure difference between the power generator and the evaporator is maintained so that the system operation can continue, and the liquid working medium can flow back. A refrigeration cycle is accomplished through the above process.

Thus, in the present invention, the working medium can flow back from the evaporator to the power generator solely under gravity action, and a preset pressure difference is maintained between the power generator and the evaporator by means of the upper valve and lower valve, so that the entire system can continue its operation.

The time interval at which the valves are opened can be controlled by means of a controller.

Preferably, water cooling or air cooling is used in the present invention. As shown inFIG. 3, in the present invention, two condensers connected in series are employed for duplex cooling, i.e., a heat storage water tank20, followed by an air-cooled condenser.

As described above, a variety of common heat sources can be used as the power source for heating up the working medium, so that the working medium can flow from the power generator into the evaporator; in addition, gravity is used as the power source for driving the working medium to flow back from the evaporator into the power generator. Thus, the complex process of electrical energy-mechanical energy conversion involved in the compressor in conventional refrigeration systems is eliminated thoroughly. In addition, the compressor-free refrigeration system in the present invention has simple structure and lower cost, and is applicable to a variety of application scenarios.

Therefore, the refrigeration system disclosed in the present invention can save energy. It can utilize a variety of common heat sources, such as water heaters and waste heat of boilers, etc., and doesn't consume electrical energy heavily when compared with compression refrigeration systems. In addition, the refrigeration system disclosed in the present invention doesn't have noise produced by compressor, and has low cost and wide applicability. The implementers can employ different heat sources, such as solar heat source, electric heat source, or waste heat of boiler, etc., according to the local conditions.