JPH04203464A - Regenerative heat exchanger of external combustion engine - Google Patents

Abstract

PURPOSE:To improve the performance of the whole body of a regenerative heat exchanger and to increase the efficiency of the engine by forming numerous sheets of wire-gauzes of two or more sorts with different heat conductivity, which are housed by superposing in a case. CONSTITUTION:In a regenerative heat exchanger 8 for high temperature and a regenerative heat exchanger 11 for low temperature, wire gauzes 36 and 37 formed of metallic wires with different heat conductivity are laminated alternatively, and housed in a case 8a and a case 11a. By using copper gauze 37 with a higher heat conductivity for the regenerative heat exchangers 8 and 11, the heat is transmitted to the inside of the wire-gauze, and the heat is accumulated effectively more than using a stainless gauze 36. Consequently, by superposing the stainless gauzes 36 and the copper gauzes 37 alternatively, the heat conductive loss can be suppressed in a low level as a whole while increasing the heat capacity, and the performance of the regenerative heat exchangers 8 and 11 can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a regenerative heat exchanger for an external combustion engine using a VM (Bulmeier) cycle.

<Prior art> Conventionally, regenerative heat exchangers for external combustion engines of this type have generally used either stainless steel or brass wire mesh, and a laminated layer of these wire meshes is housed in a case. (See, for example, Japanese Patent Publication No. 63-12240), and stainless steel has been used for low-temperature use as well, in order to achieve the same H value as for high-temperature use. Furthermore, in the past, the main method was to change the way the mesh was stacked and its shape.

<Problem to be solved by the invention> However, as mentioned above, stainless steel wire mesh, which has been used with emphasis on heat resistance, has low thermal conductivity, and in order to effectively store heat inside the wire mesh, it is necessary to The wire diameter must be reduced, leading to an increase in pressure loss.

On the other hand, if only copper is used in the regenerative heat exchanger, the heat conduction between the wire meshes is high, which increases the heat conduction loss from the high-temperature part to the low-temperature part. That is, the use of a heat exchange wire mesh made of one type of metal has various drawbacks.

In view of the above circumstances, the present invention improves the performance of the entire regenerative heat exchanger and improves the efficiency of the engine by using wire meshes made of two or more types of metals with different thermal conductivities and arranging them alternately. The purpose of this invention is to provide a regenerative heat exchanger for an external combustion engine.

<Means for solving the problem> The present invention consists of a regenerative heat exchanger for an external combustion engine, which consists of a case and a number of wire meshes that are stacked and stored inside the case. A wire mesh made of two or more metals with different thermal conductivity.

<Function> As mentioned above, wire meshes made of a metal with low thermal conductivity (e.g. stainless steel) and wire meshes made of a metal with high thermal conductivity (e.g. copper) are layered alternately, so that the inside of the wire meshes can be effectively Heat is stored, increasing the heat capacity while keeping the overall heat conduction loss low.

<Example> Hereinafter, the present invention will be explained based on drawings of embodiments.

Fig. 1 shows a VM cycle drive type external combustion engine (heat pump), in which 1 is an external combustion engine, and the high-temperature side cylinder 2 containing the piston 3 and the low-temperature side cylinder 4 containing the piston 5 are arranged at right angles. At the same time, the piston rods 21 and 22 of both pistons 3.5 are connected to a crank 23 attached to a rotating shaft 24 in a crankcase 25 by a connecting rod 19.20, so that they reciprocate out of phase. Firstly, a heater tube 6 having fins 7 for heating working gas at a high temperature level is connected to the temperature control cylinder 2, and a high temperature regenerative heat exchanger 8 and medium temperature gas are connected to the heater tube 6. A medium-temperature heat exchanger 9 for dissipating heat is provided, and a low-temperature heat exchanger 12 is connected to the low-temperature cylinder 4 via a low-temperature gas tube 13.
2 is provided with a low temperature regenerative heat exchanger 11 and a medium temperature heat exchanger 10, and this medium temperature heat exchanger 10 and the medium temperature heat exchanger 9 are communicated through a communication pipe 14. Furthermore, a circulation pump 27 is connected to the low temperature side heat exchanger 12 through a cold water pipe I8.
A cooler 17 is connected via
A heater 15 is connected via the heater 15, and the heater 15 and cooler 17 are provided within the indoor unit 30. 28
1 is a heat exchanger for exhaust heat that is branch-connected from the heating three-way valves 1 and 32 provided in the hot water pipe 16, and two are branch-connected from the cooling three-way valves 33- and 34 provided in the cold water pipe 18. This is a heat exchanger for waste heat. 35 is a burner that heats the heater tube 6. In this case, the high-temperature regenerative heat exchanger 8 and the low-temperature regenerative heat exchanger 11 are installed in the cases 8a and lla with a wire mesh 36.
37 stacked alternately (Fig. 4A)
, see B).

For example, as shown in FIG. 5 as an example, the details of the internal wire mesh are basically the same structure as the conventional wire mesh type, but stainless steel wire mesh 36 and copper wire mesh 37 are alternately stacked. As shown in FIG. 6, the stainless steel wire mesh 36 and the copper wire mesh 37 may not be alternately laminated every 11 sheets, but may be alternately laminated every 2 to 3 sheets.

In addition to the combination of stainless steel and copper, stainless steel and aluminum (M conductivity? 7.5 kcal/*l+℃)
, or brass (85 kcal/+h'C), or a combination of three or more of these metals.

Next, to explain this operation, in an external combustion engine, when the rotating shaft 24 rotates and the crank 23 rotates, the piston 3 of the high-temperature side cylinder 2 and the piston 5 of the low-temperature side cylinder 4, which are arranged at right angles, alternate. Operation is performed by reciprocating and interlocking with a constant phase difference.

Here, the working gas exiting the high-temperature side cylinder 2 is heated by the heater tube 6 and flows from the high-temperature regenerative heat exchanger 8 to the medium-temperature side heat exchanger 9.

During heating, a heating medium is taken out from the medium-temperature side heat exchanger 9 and 10 and guided to the heater 15 for heating, and a cooling medium is taken out from the low-temperature side heat exchanger 12 and transferred to the exhaust heat "heat exchanger". 29 and pumps up heat from outside.5
<1 During cooling, the cooling medium is guided from the low-temperature side heat exchanger 12 to the cooler 17 for cooling, and the heating medium is taken out from the medium-temperature side heat exchanger 59.10 and transferred to the exhaust heat heat exchanger 28. The heat of this medium is discharged outside.

That is, in the regenerative heat exchangers 8 and 11, the working gas reciprocates in accordance with the movement of the piston 3.degree. 5, and heat absorption and heat radiation are repeated by the movement of the gas on the high temperature side and the low temperature side. The time is very short; when the piston rotation speed is 1000 rpm, the time required for heat exchange between the gas and the wire mesh is 30 m5ec.
(See Figure 2).

For this reason, the regenerative heat exchangers 8 and 11 are required to quickly exchange heat with the gas so that the heat on the surface quickly reaches the core of the wire mesh and efficiently stores heat.

If a copper wire mesh 37 with high thermal conductivity is used in the regenerative heat exchanger 8.11, heat will be transmitted to the inside of the wire mesh and stored more effectively than a stainless steel wire mesh 36 (see FIG. 3). Therefore, by alternately stacking the stainless steel wire mesh 36 and the copper wire mesh 37, it is possible to increase the heat capacity while keeping the overall heat conduction loss low, thereby increasing the performance of the regenerative heat exchanger 8.11. can.

Table 1 shows a comparison of the physical properties of stainless steel and copper.

<Effects of the Invention> As described above, in the regenerative heat exchanger for an external combustion engine of the present invention, the heat conductive member housed inside is made of alternating layers of wire mesh with high thermal conductivity and wire mesh with low thermal conductivity. As a result, heat is transmitted to the inside of the wire mesh, and the heat is stored effectively, and the heat conduction loss can be kept low while increasing the heat capacity, and its performance can be improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and Fig. 1 is a schematic diagram of an external combustion engine, and Fig. 2 is a model explanation of the velocity of gas passing through the regenerative heat exchanger when the engine speed is 10 (10 rpm). Figure 3 is a temperature change explanatory diagram showing a comparison of heat conduction to the inside of the regenerative heat exchanger made of wire mesh or stainless steel and copper, and Figure 4 A and B are plane views of the regenerative heat exchanger. Fig. 5 is an explanatory diagram showing a stacked state of a stainless wire mesh and a copper wire mesh, and Fig. 6 is an explanatory diagram showing a stacked state of a plurality of stainless steel wire meshes and copper wire meshes. 1... External combustion Engine, 8... High temperature regenerative heat exchanger, 8a
...Case, 11...Low temperature regenerative heat exchanger, 11a
...Case, 36...Stainless steel wire mesh, 37...
・Copper wire mesh. Fig. 2 wC3 Fig. Numazure Fig. 4 (A) Page 4 (B) m5 Fig. 6

Claims (1)

[Claims] 1. In a regenerative heat exchanger for an external combustion engine, which is composed of a case and a number of wire meshes that are stacked and stored in the case, the multiple wire meshes are made of two or more types of metals with different thermal conductivities. A regenerative heat exchanger for an external combustion engine, characterized in that it is formed of: