JPH01244173A - Closed-circuit heat engine - Google Patents

Abstract

PURPOSE:To recover waste so efficiently by circulating a heating medium being ebulliently evaporable at room temperature or such less than that, while gasifying it by heat reception from a cold heat source, and utilizing a volumetric difference between liquid and gas. CONSTITUTION:A prime mover 1 is driven by a heating medium turned to high temperature and pressure gas by a gasifying heat exchanger 4. The heating medium, whose pressure and temperature are lowered by driving this prime mover 1, is further cooled by a liquefying heat exchanger 2, turning to a low pressure and temperature liquid. This liquefied heating medium is pressurized by a pressure-feed pump 3, and fed into the gasifying heat exchanger 4. The heating medium selects such one that is ebulliently evaporable at lower temperature than that of a supply heat source, so that even if it is a low temperature heat source, the heating medium is gasifiable in using such one. Thus, the gasified heating medium is fed to the prime mover 1 and mechanical energy is taken out.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a closed-circuit heat engine that recovers waste heat or relatively low-temperature heat and extracts it as mechanical energy.

(Prior Art and Problems to be Solved by the Invention) Typical heat engines include internal combustion engines that burn fuel directly within the engine, and external combustion engines that operate by receiving heat from an external heat source.

In an internal combustion engine, engine output can be controlled relatively easily and rapidly, whereas in an external combustion engine, rapid output control is difficult due to cost considerations, making it difficult to apply to small engines and the like.

By the way, both types of engines require a high-temperature heat source, such as by burning fuel, and efficient operation cannot be expected with a low-temperature heat source, so low-temperature waste heat, etc., which is dumped outside, is used as a heat source. is difficult to implement in practice due to cost and other considerations.

An object of the present invention is to provide a volume difference heat engine, which is a type of external combustion engine, which can recover thermal energy from low-temperature waste heat or a heat source below the outside air temperature as a heat source, and is also capable of rapid output control. With the goal.

(Means for Solving the Problems) In order to achieve such an object, the present invention includes a prime mover driven by supply of a vaporized heat medium, a liquefaction heat exchanger that liquefies exhaust gas from the prime mover, and a liquefaction heat exchanger that liquefies exhaust gas from the prime mover. , a pump that pressurizes the liquefied heat medium, a vaporization heat exchanger that vaporizes this high-pressure liquid by receiving heat from an external heat source, and a pressure regulating valve that adjusts the vaporization pressure of the gas sent to the prime mover. Configure a closed circuit. A heat medium having a boiling point in the room temperature range or lower was sealed as a heat medium circulating in this closed circuit.

(Operation) A heat medium that boils and vaporizes at room temperature or lower temperature is circulated, and it is vaporized by receiving heat from a low-temperature heat source.
Since work is extracted by utilizing the difference between the circulating heat medium liquid and gas, the low-temperature waste heat that was conventionally released to the outside can be efficiently recovered and extracted as mechanical energy. .

Further, although the present invention is a type of external combustion engine, the boiling point can be adjusted based on the characteristics of the saturated liquid line of the heat medium by controlling the pressure within the system, thereby enabling rapid output control.

(Example) FIG. 1 shows a first example. This embodiment is of a type that operates using relatively high temperature waste heat.

In the figure, 1 is a volume differential prime mover consisting of, for example, a reciprocating piston engine, 2 is a liquefaction heat exchanger that removes heat from the low-pressure low-temperature gas discharged from the prime mover 8!1, and liquefies it; 3
4 is a pressure pump that pressurizes the liquefied low-temperature, low-pressure liquid, and 4 is a vaporization heat exchanger that receives heat from an external heat source to vaporize the pressurized liquid into a high-pressure, high-temperature gas. The high pressure and high temperature gas from the heat exchanger 4 is transferred to the pressure regulating valve 6.
By supplying the volume difference prime mover 1 via
The operation of the prime mover 1 is changed.

The heat medium used in these tight leap circuits is
The boiling point at atmospheric pressure is in the room temperature range or lower, such as ammonia (boiling point -33℃), 70N12 (
(boiling point -29°C), ethyl (boiling point 34°C), etc. are used. Of course, the heat medium is not limited to these.
Depending on the temperature of the external heat source to be recovered, an appropriate heat medium may be selected from known heat media with a lower boiling point than this.

Therefore, the heat medium can be vaporized even if the external heat source of the vaporization heat exchanger 4 is at a temperature lower than, for example, 1 degree Celsius outside air. ).

In addition, the boiling point of these heat media can be freely changed by adjusting the pressure in the vaporizing heat exchanger 4 using the pressure regulating valve 6 to perform saturated liquid line control, and output control can be performed based on this. can.

Next, the operation of the present invention will be explained with reference to the basic theoretical diagram shown in Figure tj113.

First, in FIG. m1, the prime mover 1 is driven by a heat medium that has been turned into a high-temperature, high-pressure gas by the vaporizing heat exchanger 4. The heat medium whose pressure and temperature have decreased by driving the prime mover 1 is
It is further cooled in the liquefaction heat exchanger 2 and turns into a low-pressure, low-temperature liquid. As described above, the heat medium remains in a gaseous state even at room temperature or below, so the gas discharged from the prime mover 1 will not liquefy unless it is further cooled. In this case, since the temperature of the heat supply source is relatively high and the boiling point of the heat medium used is correspondingly high, the liquefaction heat exchanger 2 cools the heat medium by releasing heat to groundwater or the atmosphere. Liquefied name.

The liquefied heat medium is pressurized by the pressure pump 3 and sent to the vaporization heat exchanger 4. The vaporization heat exchanger 4 receives heat from an external heat source and vaporizes the liquefied heat medium.The heat medium is selected to be one that boils and vaporizes at a lower temperature than the temperature of the supplied heat source. Even a low-temperature heat source lower than the outside air temperature can be used to vaporize the heat medium.

Note that it is of course possible to use waste heat emitted from various devices and devices as the heat source.

By supplying the heat medium thus vaporized to the prime mover 1, the prime mover fJJJml is rotationally driven, and its output can be extracted as mechanical energy.

The work done by this closed circuit heat engine is the output generated by the Hara 4J Iso 1 minus the work consumed by the pump 3 and the liquefaction heat exchanger 2.

By the way, in this case, by controlling the pressure regulating valve 6 to lower the internal pressure of the vaporizing heat exchanger 4, boiling of the heat medium, α
In other words, the vaporization temperature decreases and the amount of gas that drives the prime mover 1 increases.As a closed circuit system, the lower the system pressure, the greater the output. This point is completely opposite to that of a marine heat engine, whose output increases by increasing the pressure.

If the pressure in the system is increased by operating the pressure control valve 6, the boiling point will be raised, the amount of steam generated can be reduced, and the output can be lowered.

At this time, the temperature of the heat medium of the liquefaction heat exchanger 4 increases relatively while remaining in liquid state, so that the heat supplied from the external heat source can be stored in the heat medium. When lowering the internal pressure, the heat medium is instantly vaporized with good response, and the prime mover 1 can be rapidly accelerated.

Next, the generated work will be further explained according to the basic theoretical diagram of fjS3 diagram.

In this figure, the compression piston 10 corresponds to the pressure-feeding pumpco 3, and the expansion piston 11 corresponds to the prime mover 1. In this example, the compression piston 10 and the expansion piston 111' are interlocked with each other, and the cylinder chambers 10A and IIB are connected to each other. It's communicating.

The compression piston 10 pressurizes the liquefied heat medium.
During the transition from the compression piston 10 to the expansion piston 11 with the same pressure, the heat medium receives heat and vaporizes. Vaporized heat! The expansion piston 11 is driven by the A quality, and this movement is taken out as an output, and a portion is consumed to drive the compression piston 10.

Generally, when a liquid absorbs heat from the outside and changes into a gas, its volume increases significantly. Therefore, at the same pressure *
If the expansion piston 11 is driven at the same pressure by utilizing the volume difference between the expanding liquid and the gas, the work generated will be much greater than the work consumed by the compression piston 10, which pressurizes the liquid.

The pressures in the cylinder chambers 10A and IIA are the same, but by increasing or decreasing this pressure, the boiling point, α, at which liquid changes to gas changes, and as mentioned above, the lower the pressure, the easier it is to vaporize, and the difference in volume is reduced. Because of the configuration in which the prime mover 1 is driven using the
The output can be easily and responsively controlled based on the characteristics of the saturated liquid line.

In addition, in FIG. 3, Q=heat amount, L=liquid, G=gas,
M=mass, ■=volume (effective cylinder volume), P=positive pressure F=output, W=work, T=humidity temperature S=saturated liquid line, l=efficiency, a, b, c=constants, then the following The theoretical formula holds true.

M1=M2 (the masses of liquid and gas are equal) P1=P2(
The pressure of the liquid and the gas are equal) T1≦1゛2 (the gas has a higher temperature due to the heat received from the heat source) Q1≦Q2 (the gas has a larger calorific value due to the heat received from the heat source) ■1≦V2 (vaporization (equivalent to volumetric expansion due to) P/'I
' = c (temperature is proportional to pressure) W/Q = a (work is proportional to heat) P = b/W (pressure is inversely proportional to work) F2 - F1 = F3 (from the output of the expansion piston 11 to the output of the compression piston 10 When the driving force is subtracted, the positive work corresponding to the volume difference) F3Xη=W (Actual amount of work with the mechanical efficiency of the system 't tft) Next, ff12y in Figure 2! , to explain the example,
This is a case where the heat source supplied to the vaporization heat exchanger 4 is lower temperature than in the Pt51 example, and the heat medium used is selected to have a lower boiling point. In order to obtain the cooling performance necessary for liquefying a low heat medium, a heat pump 5 with extremely high heat transfer efficiency is provided.

Does the heat pump 5 absorb heat inside the liquefaction heat exchanger 2? 1
FIS5A is also installed inside the heat exchanger 4 for vaporization.
A compressor 5C is provided, and a closed circuit is connected between them, and a compressor 5C is added to circulate the refrigerant sealed inside.

The refrigerant pressurized by the compressor 5C becomes a high-pressure, high-temperature gas, releases heat in the heat radiation section 5B of the vaporization heat exchanger 4, and becomes a high-pressure, low-temperature liquid.

Since the pressure of this high-pressure liquid rapidly decreases downstream of the evaporation valve 5D, the heat absorption section 5A'' of the liquefaction heat exchanger 2 responds accordingly.
C' expands and evaporates, taking heat from the surroundings, lowering the temperature of the heat medium in the liquefaction heat exchanger 2, and promoting its liquefaction. The low-pressure, low-temperature gas is then pressurized again by the compressor 5C to become a high-pressure, high-temperature gas and circulated to the heat radiation section 5B.

By installing the heat pump 5 with extremely high heat transfer efficiency in this way, the temperature of the heat source supplied to the vaporization heat exchanger 4 is relatively low, and therefore the heat used 1&
Even if the boiling point of the material is low, it is possible to reliably liquefy the material by keeping the cooling efficiency of the liquefaction heat exchanger 2 low. Furthermore, the heat recovered by the heat absorption part 5A of the heat pump 5 is released to the heat medium by the heat radiation part 5B, so that the output efficiency of the closed circuit heat engine is improved accordingly.

(Effects of the Invention) As described above, according to the present invention, a heat medium that boils and vaporizes at room temperature or lower temperature is circulated, and is vaporized by receiving heat from a low-temperature heat source. In order to extract work by using the volume difference between liquid and gas,
The low-temperature waste heat that was conventionally released to the outside can be efficiently recovered and extracted as mechanical energy.

Furthermore, although the present invention is a type of external combustion engine, it is possible to rapidly control the output based on the characteristics of the saturated liquid line of the heat medium by controlling the pressure within the system. Since heat can be stored in the heat medium, this can be used to quickly accelerate the vehicle with good response when the next output is increased.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram showing an embodiment of Pt51 of the present invention, Figure 2 is a block diagram showing an embodiment of Pt51 of the present invention.
The figure is a block diagram showing the second embodiment, and FIG. 3 is a basic theoretical diagram of the present invention. DESCRIPTION OF SYMBOLS 1... Prime mover, 2... Heat exchanger for liquefaction, 3... Pump, 4... Heat exchanger for vaporization, 5... Heat pump, 6... Pressure adjustment valve.枳 C Lu Yu

Claims (1)

[Claims] A prime mover driven by the supply of a vaporized heat medium, a liquefaction heat exchanger that liquefies exhaust gas from the prime mover, a pump that pressurizes the liquefied heat medium, and a supply of heat from an external heat source to this high-pressure liquid. The present invention is characterized by comprising: a vaporizing heat exchanger that vaporizes the gas that it receives; a pressure regulating valve that adjusts the vaporizing pressure of the gas sent to the prime mover; and a heat medium whose boiling point is in the normal temperature range or lower as the circulating heat medium. Closed circuit heat engine.