JPS58175792A - Heat accumulation type heat exchanger - Google Patents

Abstract

PURPOSE:To make the thermal stress in a heat accumulation body small in a heat exchanger of heat accumulation type, by dividing the formation of a heat accumulation body into the upper, the middle and the lower parts, and by forming the upper and the lower parts of bricks in layers for heat accumulation, while by making the middle part of pebbles in layers. CONSTITUTION:The outer surface of a heat accumulation body is encircled by a heat insulating material 1, and laid bricks (checkerwork) 6 for heat accumulation in the lower part, a pebble layer 7 for the middle part, and a checkerwork 8 for the upper part are formed in layers on a supporting plate 2. Heating air flows from an opening 4 to an opening 5, while cooling air is reversely flown from the opening 5 to the opening 4. By forming the heat accumulation body in such a manner, the heat transfer surface per unit volume can be made small, so that the thermal stress in the heat accumulation body is made small, accordingly, the part of a pebble layer is prevented from being destroyed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a regenerative heat exchanger, and more particularly to a regenerative heat exchanger with a shape suitable for obtaining high-temperature gas using combustion gas.

[Prior art and its problems]

As shown in FIG. 1, the heat storage type exchanger alternately passes hot air and cold air through a heat storage body, and radiates the heat absorbed during the heating period during the cooling period. The heat storage body has the Takaya Life section at the top and the low temperature section at the bottom, making it easy to support the heat storage body, and hot air flows in the opposite direction from the top to the bottom, and cold air flows in the opposite direction from the bottom to the top.

Heat storage bodies include spherical pebbles, hole-shaped charcoal briquettes, checkerboard stacking bricks, etc., and are wired in an R-shape.

Conventionally, heat storage type exchangers have the following drawbacks. The first point is that in the pure pebble heat storage structure of the heating gas constant force type, the temperature gradient of each pebble is constrained.
It is unavoidable that the I& and heating gas outlet temperatures become high. The resulting problem is that at the beginning of the next cooling cycle, the difference between the incoming cold air and the pebble becomes large enough to cause a thermal shock that rapidly cools the lower half of the pebble, causing the pebble to collapse due to thermal stress. Destroy. The second point is that the pebble heat storage body has a large heat transfer area per nested volume, so in the constant heating gas wrinkle method, the pebble temperature gradient in the upper part of the acid is likely to be large. The temperature of the half part rises rapidly, and the pebble is prone to breakage due to thermal stress. The third point is A1 because the checker has a small heat transfer area per fathom volume.
The disadvantage is that it tends to become large.

[Purpose of the invention]

The present invention was made to solve the above-mentioned drawbacks, and an object of the present invention is to provide a heat storage cedar heat exchanger 4 that reduces thermal stress in the upper heat storage body during heating and the lower heat storage body during cooling.

[Summary of the invention]

The present invention divides the shape of the heat storage body into three parts: an upper part, a middle part, and a lower part, and the upper part and the lower part are made of checkered bricks for heat storage, and the middle part is made of pebble and 1-9 heat storage type heat exchanger. It is a vessel.

〔Effect of the invention〕

According to this invention, it is possible to reduce the thermal stress of the heat storage body by reducing the heat transfer rfJfJ per unit volume.

[Embodiments of the invention]

Calculating the thermal stress of a heat storage body is very difficult, and generally the thermal stress is predicted by obtaining the average temperature rise rate of the heat storage body. For example, it is said that alumina pebbles break at about 40 k/min.

Next, the energy balance equation at the top of the heat storage body of the heat storage type exchanger is given by the following equation.

Here, m: heat storage heavy wave, C: heat storage body specific heat.

Tm: temperature of the heat storage body, t: time, h2@heat transfer wheel between the body and the heating gas, input: heat transfer area, 'rg: heating is smlf%, q': thermal inertia. Here, when q'=O and deformed, it becomes dl'm.From this, @To lower the hair gradient dt, the specific heat C takes a constant value depending on the material, so reduce the temperature difference Δ゛r.
Alternatively, you can think of ways to reduce the heat transfer area (knee) or reduce the heat transfer rate. Among these, it is difficult to change the heat transfer coefficient and the difference ΔT significantly, so the best way is to change them. This method can be easily achieved by changing the shape of the heat storage body from pebble to checkered. If, the thermal stress can be lowered.

You can also change - by n by changing the diameter of the pebble. Since the overall shape t of the pebble is constant and is inversely proportional to the diameter, it is possible to reduce the thermal stress by increasing the pebble diameter.

FIG. 2 is a schematic cross-sectional view showing an embodiment of the heat storage type exchanger according to the present invention. The heat storage body is divided into three parts: a checker 8 in the upper part, a pebble 7 in the middle part, and a checker 6 in the lower part, and is supported by a support plate 2. The outer periphery of the support plate 2 is fixedly supported by the heat insulating material 1. A heat insulating material 1 is placed around the outer periphery of the heat storage body to reduce heat loss from the cold wind and the heat storage body.

By changing the shape of the heat storage body in this way, the zero-order advantage of being able to make the unit unit smaller than K is that if the thermal stress λ applied to the heat storage body is constant, by reducing -, the difference between the heat storage body and the heating wind can be reduced. The honey difference ΔT can be increased and the heating time can be shortened. Also checkered @ on the top and bottom of the heat storage body.
Since the temperature gradient is smaller than that of the pebble, the temperature difference in the entire heat storage body can be increased, and by lowering the temperature of the first part of the forging, the heat shock can be reduced.

[Other embodiments of the invention]

In addition, as an example of the second embodiment, as shown in Fig. 3, the diameter of the pebble can be made larger at the upper and lower parts and smaller at the middle part, thereby changing the heat transfer area per volume per second. Achieved too. Further, as a modification of the second embodiment, the thermal stress can be reduced by dividing the diameter of the pebble into not only three parts but also more parts, for example, 4, 5, and 6 parts.

[Brief explanation of the drawing]

Figure 41 is a schematic diagram of a conventional heat storage type exchanger, fs
FIG. 2 is a schematic cross-sectional view showing a practical example of the heat storage type exchanger according to the present invention, and FIG. 3 is a schematic cross-sectional view showing another embodiment. 2... Support plate, 6... Checker, 7... Pebble, 8... Checker, 9... Large pebble, 10...
・Small Pebble, 11...Large Pebble. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) The shape of the heat storage body is divided into three parts: an upper part, a middle part, and a lower part, and the upper part and the lower part are made of checkers (heat storage stacking bricks), and the middle part is made of pebbles. Heat storage form exchanger. (2) The size of the heat storage pebble is divided into three parts: upper part, middle part, and upper part.
The heat storage type exchanger according to claim 4!1, characterized in that the heat storage type exchanger is divided into parts, and the upper and lower parts are set further apart from the middle part.