JPS61134596A - Heat exchanger for heat pump device - Google Patents

Abstract

PURPOSE:To provide a heat exchanger for heat pump device equipped with highly reliable condenser and evaporator by a structure wherein member for airtight sealing is inserted between heat exchanger tube and partition wall for joining each other so as to allow the tube to expand freely. CONSTITUTION:If the partition wall 8 provided in a heat exchanger and the heat exchanger tube 6 are fixed to each other by means of welding or the like, stress is generated between the nest of heat exchanger tubes 6 and the outer wall 7 of a condenser due to the difference of the elongations of the members at the outer wall and the nest of tubes because said members have different temperature from each other, resulting in producing cracks at the fixed point or bucking in the nest of tubes and consequently stopping the function of a heat pump device. In order to prevent the cracks at the fixed point or bucking in the nest of tubes as mentioned above, the heat exchanger tube is made expansible in the direction of the axis of the tube without fixing the heat exchanger tube to the partition wall at the portion, through which the heat exchanger tube pierces the partition wall. In order to keep the airtightness between the tube 6 and the partition wall 8 at the expansible part 9, elastic sealing member 10 is inserted between the tube 6 and the partition wall 8 and kept in place by a keep plate 11, which is fixed to the partition wall by means of a fixing means such as screws or the like.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a heat exchanger for a heat pump device.

[Technical background of the invention and its problems]

2. Description of the Related Art In general, a heat pump device shown in FIG. 6 is known, which uses a low-temperature heat source fluid such as heated wastewater from a factory to produce a high-temperature heat source fluid such as high-temperature water.

In particular, compression type heat pump devices in which the compressor 15 is driven by an electric motor or heat engine are widely used today because they can utilize thermal energy several times as much as the input energy.

However, with the recent rise in the price of fossil fuels, the ratio of the energy used to the input energy has been improved, and the compressor drive energy can be reduced for the same amount of heat output, resulting in significant energy savings.

From this perspective, heat pump devices are being considered for large building air conditioning and district heating and cooling systems. As a method of extracting higher-grade thermal energy than using separate heat pump devices in each household, as shown in No. 611g1, low temperature cycles and high temperature cycles are stacked in two stages and operated as a heat pump device. The medium coming out of the outlet 13 is heated to about 100° C. and comes out in a state that is very easy to use.

However, there is one problem here. That is, compared to conventional condensers, the tube 6 for narrow heat exchange through which a high temperature medium flows expands and is restricted by the partition wall 8 and the condenser outer wall 7 shown in FIG. 7. Compressive force acts on the tube, causing it to buckle.
Cracks may occur in the partition wall and cause it to collapse.

This applies not only to the condenser but also to the partition wall provided at the tube end of the evaporator 14.

[Purpose of the invention]

In order to improve the drawbacks of the heat exchangers used in the conventional condensers and evaporators for heat pumps, this invention has a structure in which heat exchange tubes can be freely expanded and contracted, and a highly reliable condenser and evaporator are provided. The purpose of the present invention is to provide a heat exchanger for a heat pump device.

[Summary of the invention]

This invention is characterized by the fact that the heat exchange tube and the partition wall are not rigidly connected by welding, brazing, soldering, or diffusion bonding, but instead an airtight member is inserted to allow the tube to expand and contract while maintaining airtightness. This is a heat exchanger for a heat pump device.

[Effects of the invention] This invention prevents cracks occurring in the partition walls of the condenser and evaporator and buckling of the heat exchange tubes, which can be seen during long-term operation, and there is no leakage of the working medium. Replenishment becomes unnecessary.

[Embodiments of the invention]

An example of the heat exchanger used in the condenser and evaporator of the present invention, which has the above-mentioned effects, will be explained.

FIG. 1 shows an example of a condenser, in which the refrigerant flows from the top to the bottom. The low-temperature liquid flows from the left to the right in the diagram, where it is heated and becomes a high-temperature liquid, which is then used as an electric heat source. The refrigerant is supplied to pressure chambers 1, 2, 3, 4 and four heat exchange chambers, and in order to improve cycle efficiency, the pressure and condensation temperature of each chamber are controlled from pressure chamber 1 (upstream) to pressure chamber 4 (downstream). As it flows, it becomes under high pressure and temperature. The fluid heated in the condenser flows into the pressure equalization chamber 5 on the left, flows through the tube group 6 for heat exchange, exchanges heat in each pressure chamber, and becomes a high-temperature liquid in sequence, and is divided into 6 tubes in the collection chamber on the right. The liquids flow together and flow out to the outside.

When the condenser outer wall 7 and the heat exchanger tube group 6 are operated in this manner, stress is generated in the tube group and the outer wall due to the difference in member temperature between the condenser outer wall 7 and the heat exchanger tube group 6, and the difference in the expansion and contraction length of each member. If the provided partition wall 8 is fixed by means such as welding, cracks will occur at the fixing points and buckling of the pipes will occur, causing the heat pump device to stop functioning.

For this reason, in order to prevent buckling at fixed points and pipes, the heat exchange tubes are not fixed at the part where they normally pass through the partition wall, but are made to be able to expand and contract in the axial direction (lengthwise direction) of the tubes.

A partially enlarged view of the flexible portion 9 is shown in FIG. In the figure, in order to maintain airtightness between the tube 6 and the partition wall 8, an elastic sealing member 10 is inserted and a holding plate 11 is fixed to the partition wall using screws or other means.

By the means described above, the condenser can freely expand and contract between the pipes and the outer wall, and the operating temperature range of the refrigerant is not limited, making it possible to prevent troubles occurring in the partition walls and pipes. This means that the temperature of the working medium is not regulated even in the process of reaching a steady operating state, so there are no restrictions on the operating method when starting or stopping the heat pump, making it possible to provide a highly functional heat pump.

[Other embodiments of the invention]

There are various methods of maintaining airtightness while being expandable and contractible. In addition to the embodiment shown in FIG. 2, there are various methods as illustrated in FIGS. 3 to 5. The airtight method that can be used is not particularly limited. The present invention is not limited to a tlI/l condenser, but can be similarly implemented in an evaporator.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a condenser of the present invention, FIG. 2 is a partially enlarged sectional view of FIG. 1, FIGS. 3 to 5 are cross-sectional views showing other embodiments of the present invention, and FIG. 7 shows an example of a cycle of a heat pump device, and FIG. 7 is a sectional view of a conventional condenser. 6... Heat exchange tube 8... Partition wall 9... Expandable portion 10... Seal member 11... Presser plate 12... Condenser 14... Evaporator 15... Compressor Agent Patent attorney Kensuke Norichika (and 1 other person) Figure 1 Figure 4 Figure 5 Figure 6 L
−−−−−−−−−−−1 Figure 7

Claims (1)

[Claims] A heat pump device that is used in a heat pump device that includes a compressor that compresses a working medium sealed therein, a condenser that condenses the working medium, and an evaporator that evaporates the working medium. At least one of them holds a plurality of heat exchange chambers with different pressure levels, and there is a tube group installed over the entire length of the heat exchanger through the partition wall of the heat exchange chamber, and the section where this tube group normally passes through the partition wall is provided. A heat exchanger for a heat pump device, characterized in that the tubes can be freely expanded and contracted in the length direction, and the partition walls are made airtight.