JPS6160344B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to improvements in heat pumps.

From the standpoint of effective use of heat, heat pumps
In recent years, it has come to be utilized in various fields, especially as an energy saving measure. The present invention aims to provide a heat pump devised to reduce the required power from the viewpoint of energy saving.

Generally, the cycle of a heat pump is as shown in FIG. That is, heat is absorbed from the outside by evaporating the working fluid in the evaporator 1, and the evaporated vapor is compressed in the compressor 2 to increase the temperature and pressure.
Heat is dissipated to the outside in the condensing section 3, and the working fluid becomes a liquid. This liquid is throttled and expanded by an expansion valve 4 and returned to the evaporator 1, and the cycle ends.

To explain the above cycle according to the Pi diagram of the working fluid shown in Fig. 2, the working fluid at the outlet of the evaporator 1 is saturated vapor, and this vapor is sucked into the compressor 2 and is converted to high temperature and high pressure. compressed into steam.
The amount of compression work at this time is determined by △i ₂ =i ₂ −i ₁ . The vapor from the compressor 2 is cooled and condensed in the condensing section 3 and becomes a saturated liquid. While passing through the expansion valve 4, this high-pressure liquid is throttled and expanded at an enthalpy constant of →. The low-temperature, low-pressure working fluid that comes out of the expansion valve 4 absorbs heat from the surroundings in the evaporator 1 and evaporates. The amount of heat at this time is △i ₁ = i ₁
−i ₄ and represents the refrigeration effect per unit weight of working fluid.

As stated at the beginning, the present invention relates to improvements in heat pumps, and in particular to reducing the power required for the compressor. The power p of the compressor is given by the product of the compression work Δi ₂ and the circulating amount W of the working fluid. Further, the amount of circulation of the working fluid is given by the quotient of the total amount of heat q taken from the surroundings when the working fluid evaporates, divided by the refrigeration effect Δi ₁ of the working fluid. Therefore, it can be seen that the power of the compressor is inversely proportional to the refrigeration effect. In view of these facts, the present invention increases the refrigeration effect by forming the working fluid condensation section in multiple stages (two stages in the illustrated example) as shown in _{FIG .} This is intended to reduce the required power P.

Next, one embodiment of the present invention shown in FIG. 4 will be described. In the figure, the heat pump includes a compressor 11, condensing sections 12 and 13, and expansion valves 14 and 15.
and an evaporation section 16. The working fluid condensing sections 12 and 13 constitute evaporators 17 and 18, respectively;
The working fluid evaporator 16 constitutes a condenser 19, and exhaust steam or heated wastewater from, for example, a factory, led from the supply port 20 is transferred to the evaporators 17, 18 and the condenser 19.
leading to both.

The working fluid cycle in this embodiment will be explained with reference to FIG. 3. In the compressor, →
The working fluid compressed into high-temperature, high-pressure steam first discards the heat of condensation to the outside in the first condensing section 12 →
It condenses. Upon exiting the first condensing section 12, the working fluid is expanded as →' by the first expansion valve 14,
It is separated into vapor and liquid in a flash converter 21. The vapor is condensed in the second condensing section 13 in the direction '→'' and becomes liquefied, joins with the liquid from the flash tank 21 and reaches the second expansion valve 15.
The working fluid passes through the expansion valve 15, expands and expands as follows, and then takes heat from the surroundings in the evaporator section 16 and evaporates as follows.

Next, if we look at the heated wastewater etc. that entered the system from the supply port 20, first, when passing through the evaporator 18,
It receives condensation latent heat from the working fluid condensed in the first condensing section 13, and then in the evaporator 17, the working fluid is further heated by the heat discarded in the first condensing section 12. On the other hand, a portion of the heated wastewater and the like that has proceeded to the condensing section 19 gives heat to the working fluid that evaporates in the evaporating section 16 .

Although the embodiment described and illustrated here has two stages of condensing sections 12 and 13, it is also possible to have three or more stages. In short, the objects of the present invention can be achieved by providing a multi-stage condensing section. Furthermore, it is clear that a wide range of different embodiments can be constructed without departing from the technical idea and scope of this invention. It is to be understood that there is no limitation to the embodiments.

As explained above, the heat pump of the present invention includes a compressor that compresses a vaporized working fluid into high-temperature, high-pressure steam, and a heat pump for externally transmitting the heat of the working fluid that has been converted into high-temperature, high-pressure steam by the compressor. a condensing section that condenses and liquefies the fluid, an expansion valve that throttles and expands the working fluid liquefied in the condensing section, and a working fluid that is throttled and expanded by the expansion valve and evaporates it into saturated steam by taking heat from the outside. In a heat pump that includes an evaporation section and a working fluid evaporated in the evaporation section, which sends the working fluid to a vapor compressor and repeats the above cycle, the condensation section is multi-staged, and an expansion valve and a flash tank are provided in the working fluid path between each condensation section. At the same time, the flash tank separates vapor and liquid, and only the separated vapor is sent to the condensing section of the next stage, and the separated liquid is fed to the outlet of the condensing section of the next stage. Because of this, the required power of the compressor can be reduced,
Economical and suitable for energy consumption measures.

That is, the required power P of the compressor is the compression work △i ₂
is given by the product of the working fluid circulation amount W, and
The circulating amount W of the working fluid is the total amount of heat q taken from the surroundings when the working fluid evaporates, and the refrigeration effect of the working fluid △
The quotient divided by i ₁ is given by W = q/△i ₁ , and therefore,
The required power P of the compressor is inversely proportional to the refrigeration effect △i ₁ ,
This method focuses on the fact that the required power P of the compressor can be reduced by increasing this refrigeration effect △i _1. For this purpose, the condensing section is made in multiple stages. The working fluid is passed through an expansion valve and a flash tank, where it is separated into vapor and liquid. Only the vapor component is sent to the next stage condensing section to be condensed, and the liquid component is sent to the next stage condensing section. This improves the refrigeration effect in the condensing section of each stage by merging it with the outlet.

[Brief explanation of the drawing]

Figure 1 is a flow sheet for a conventional heat pump.
Figure 2 shows the cycle of the heat pump in Figure 1.
Pi diagram, FIG. 3 is a flow sheet similar to FIG. 1 showing an embodiment of the heat pump of the present invention, and FIG. 4 is a Pi diagram showing the cycle of the heat pump of FIG. 3. 11... Compressor, 12, 13... Condensing section, 1
4, 15...expansion valve, 16...evaporation section.

Claims (1)

[Claims] 1. A compressor that compresses a vaporized working fluid into high-temperature, high-pressure vapor, and a condensing section that condenses and liquefies the working fluid that has been converted into high-temperature, high-pressure vapor by releasing the heat to the outside. an expansion valve that throttles and expands the working fluid liquefied in the condensing section; an evaporation section that removes heat from the outside of the working fluid that has been throttled and expanded in the expansion valve and evaporates it into saturated steam; In a heat pump that sends working fluid to a vapor compressor and repeats the above cycle, the condensing section is multi-staged, an expansion valve and a flash tank are provided in the working fluid path between each condensing section, and the flash tank is used to collect steam. A heat pump characterized in that the separated vapor is separated into a liquid and a liquid, and only the separated vapor is sent to a condensing section at the next stage, and the separated liquid is fed together to an outlet of the condensing section at the next stage.