CN203024632U - Combined type phase-change material heat storing and heat transferring unit pipe - Google Patents

Abstract

The utility model discloses a combined phase-change material heat storage and heat exchange unit tube. The unit tube has a central tube, and 24 heat storage and heat exchange units are welded on the central tube. The heat storage and heat exchange units are separated The annular container is filled with a phase change material. Among the 24 heat storage units, each 8 ring-shaped containers is a section, and each section uses phase-change materials with the same melting point. The phase-change materials are NaF-60KF, 80.5LiF-19.5CaF ₂ , KF-15CaF ₂ The phase change temperature of the heat storage phase change material in the heat unit tube is selected according to the difference of solar radiation heat flow, which can ensure that all the heat storage materials melt at the same time, and use three phase change temperature phase change materials instead of a single phase change temperature phase change temperature. Change materials, forming a phase change energy storage system with variable temperature combination, can not only speed up the heat storage and heat release speed, but also help to improve the efficiency of the system.

Description

A combined phase change material heat storage and heat exchange unit tube

technical field

The utility model relates to an energy storage and release device, in particular to a combined phase change material heat storage and heat exchange unit tube.

Background technique

The space station solar thermal power generation system uses a parabolic concentrator to intercept solar energy and gather it into the cylindrical cavity of the heat absorber/regenerator, where it is absorbed and converted into heat energy, and part of the heat energy is transferred to the circulating working fluid to drive the heat engine To generate electricity, another part of the heat is encapsulated in multiple annular containers in the heat storage and heat exchange unit tubes, and the phase change heat storage materials in the annular containers are absorbed and stored by melting. During the shadow period of the orbit, the phase change heat storage material solidifies and releases heat near the phase transition point, and acts as a heat source for the heat engine to heat the circulating working fluid, so that the space station can still work continuously to generate electricity when it is in the shadow period.

In the existing heat absorption/regenerator structure, 23 heat storage and heat exchange unit tubes are evenly distributed in parallel on the inner wall of the cylindrical heat absorption cavity, and 24 heat storage container units are welded and fitted outside the heat storage and heat exchange unit tubes. The heat storage unit is a separate annular container filled with a single phase change material of 80.5LiF-19.5CaF2 with a melting point of 1042K.

Due to the difference in the incident heat flow of the sun on the outer wall of the heat storage and heat exchange unit tube in the axial direction and the difference in the temperature of the working medium on the inner wall, the melting rate of each heat storage unit is very different, and the phase change heat storage material of some containers melts during the orbital period. The rate changes little. This causes a waste of latent heat storage capacity, increases the quality of the system, and also causes large fluctuations in the outlet temperature of the working medium.

Contents of the invention

The utility model provides a combined phase change material heat storage and heat exchange unit tube with simple structure, convenient processing and excellent performance. For this reason, the technical scheme that the utility model adopts is as follows:

The utility model mainly includes a central tube, on which 24 heat storage and heat exchange units are welded and fitted, and the heat storage and heat exchange units are separate annular containers filled with phase change materials. Among the 24 heat storage units, every 8 ring-shaped containers from the left to the right are one section, and each section uses phase-change materials with the same melting point, and the phase-change materials are NaF-60KF, 80.5LiF-19.5CaF ₂ , KF -15CaF ₂ .

The utility model has the characteristics of compact structure, convenient processing and high heat transfer efficiency. The phase change temperature of the heat storage phase change material in the heat storage heat exchange unit tube is selected according to the difference of solar radiation heat flow, which can ensure that all heat storage materials Melting at the same time, using three kinds of phase change temperature phase change materials to replace single phase change temperature phase change materials, thus forming a phase change energy storage system with variable temperature combination, which can not only speed up the energy storage and discharge speed, but also significantly improve the heat utilization efficiency . This is of great significance for space solar heat storage systems that have strict requirements on heat storage or heat release time. Compared with the analysis and comparison of the phase change material heat exchange unit tube with a single phase change temperature, the use of a three-stage combined phase change heat storage material heat exchange unit tube has significantly improved the thermal performance of the heat absorber, and increased the outlet temperature of the working medium during the shadow period. It is beneficial to improve the efficiency of the system; the maximum temperature of the working fluid is reduced, which is conducive to improving the reliability of the heat exchange unit tube; the fluctuation of the outlet temperature of the heat absorber is reduced, and the utilization rate of the latent heat of the phase change heat storage material is improved, which is beneficial to Reduce system mass. the

Description of drawings

Fig. 1 is a schematic diagram of a cylindrical structure of a heat absorber/regenerator of the present invention.

Fig. 2 is a structural schematic diagram of a combined phase change material heat storage and heat exchange unit tube of the present invention.

In the figure, 1-combined phase change material heat storage and heat exchange unit tube, 2-working fluid inlet tube, 3-working fluid outlet tube, 4-inlet annular header, 5-outlet annular header, 6-endothermic/ Cylindrical cavity of the heat accumulator, 7 - the first section of the heat storage and heat exchange unit tube, 8 - the second section of the heat storage and heat exchange unit tube, and 9 - the third section of the heat storage and heat exchange unit tube.

Detailed ways

In order to better understand the utility model, the utility model will be further described below in conjunction with the accompanying drawings. As shown in FIG. 1 , its structure includes a cylindrical cavity 6 , a heat storage heat exchange unit tube 1 , a working fluid inlet tube 2 , a working fluid outlet tube 3 , an inlet annular header 4 and an outlet annular header 5 . As shown in Figure 2, the phase change material contained in the annular container in the first section 7 of the heat storage and heat exchange unit tube is NaF-60KF, and the phase change material contained in the annular container in the second section 8 is 80.5LiF-19.5CaF _2. The phase change material contained in the annular container in the third section 9 is KF-15CaF ₂ .

When the heat absorber/regenerator is working, the solar heat flow entering the heat absorber/regenerator cavity 6 during the sunshine period radiates part of the heat energy and transfers it to the circulating working medium, and the circulating working medium flows into the inlet annular main pipe 4 through the working medium fluid inlet pipe 2 It is distributed to each heat storage and heat exchange unit tube 1. After the temperature of the circulating working fluid is increased, it is collected into the outlet annular main pipe 5, and flows into the turbine through the working medium fluid outlet pipe 3 to expand and perform work to drive the heat engine to generate electricity; the other part of heat energy heats the heat storage exchange The outer surface of the annular container of the heat unit tube 1 melts the phase-change heat storage material inside, and the phase-change heat storage material in the annular container absorbs heat and changes from solid to liquid to store heat energy. During the shadow period of the orbit, the phase change heat storage material solidifies and releases heat near the phase transition point, and acts as a heat source for the heat engine to heat the circulating working fluid, so that the space station can still work continuously to generate electricity when it is in the shadow period.

Claims (2)

1. A combined phase change material heat storage and heat exchange unit tube, characterized in that it has a central tube, and 24 heat storage and heat exchange units are welded on the central tube, and the heat storage and heat exchange units are separated annular The container is filled with a phase change material inside the annular container. 2. A combined phase change material heat storage and heat exchange unit tube according to claim 1, characterized in that, among the 24 heat storage units, every 8 annular containers from the left side to the right side are one section, Phase change materials with the same melting point are used in each section, and the phase change materials are NaF-60KF, 80.5LiF-19.5CaF ₂ , and KF-15CaF ₂ in sequence.

Images