JPH0253703B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat pump that drives a compressor of a refrigeration cycle by a prime mover consisting of an internal combustion engine.

[Conventional technology]

The above-mentioned heat pump consists of a refrigeration cycle, a prime mover consisting of an internal combustion engine that drives its compressor, a hot water tank that collects the exhaust heat of the prime mover and heats it with circulating water, and stores the heat in the hot water. A type of hot water supply system is known that includes a hot water supply pipe that opens at the upper end of the hot water tank. This prime mover-driven heat pump has the advantage of having a large coefficient of performance in terms of primary energy, since the exhaust heat from the prime mover can be recovered into hot water using the coolant of the prime mover, stored in a hot water tank, and used for hot water supply.

FIG. 1 shows a hot water tank portion of a conventional motor-driven heat pump as described above. In Figure 1, 9 is a hot water tank;
10 is a hot water storage heat exchanger disposed at the bottom of the hot water tank 9; 11 is a water supply pipe that opens at the bottom of the hot water tank 9;
Reference numeral 12 denotes a hot water supply pipe that opens at the upper end of the hot water tank 9 .

In the conventional system configured as described above, circulating water, which is cooling water that has recovered exhaust heat from the prime mover, flows to the hot water storage heat exchanger 10 as shown by the arrow in FIG.
By heating the hot water stored in the lower part of the hot water tank 9 and gradually increasing the temperature of the hot water in the hot water tank 9 through natural convection, the temperature inside the tank is almost the same between the upper and lower parts, and is uniform down to the lower part. Therefore, the effective amount of hot water stored can be increased. And, as shown in Utility Model Application Publication No. 57-11475, the first
It is also possible to install a heat exchanger for hot water storage up to a point slightly higher than that shown in the figure, or to install a large heat exchanger for hot water storage in the middle of the hot water tank in the vertical direction, as shown in JP-A-56-102665. Conceivable.

[Problem to be solved by the invention]

However, the motor-driven heat pump shown in Fig.
Do you only operate the prime mover for cooling or heating?
Because the temperature of the hot water stored in the hot water tank rises almost uniformly from top to bottom and almost in proportion to the operating time of the prime mover, it takes a considerable amount of time to reach the temperature required for hot water supply, which is generally 45 degrees Celsius or higher. Even if a sufficient amount of heat is stored in the hot water tank, the hot water temperature is often below the required temperature, which often causes dissatisfaction among users, especially when the temperature of the hot water stored in the hot water tank is low. If the operating time of the prime mover is short, the temperature of the stored hot water discharged from the hot water tank will be low, so the prime mover may be operated for hot water supply, or the auxiliary heater may be used to heat the stored water or circulating water. The problem is that it needs to be done. This problem can be solved even if the hot water storage heat exchanger is installed slightly above the one in Figure 1, as shown in Japanese Utility Model Application Publication No. 57-11475.
almost unsolvable.

In addition, as shown in Japanese Patent Application Laid-open No. 56-1062665,
Since a large heat exchanger for hot water storage is installed in the center of the hot water tank, this heat exchanger becomes heavy, which not only makes it difficult to suspend it in the hot water tank, but also makes it difficult to connect the stored water and circulating water. When the temperature difference is small, the amount of heat exchanged in the upper part of these hot water storage tanks increases, causing the problem that the amount of heat in the circulating water cannot be used effectively.

This invention solves the above-mentioned problems and can supply hot water at the required high temperature with a short-time operation of the prime mover, and also makes the hot water storage heat exchanger small and lightweight so that it can be easily installed in the hot water tank. The purpose of the present invention is to provide a motor-driven heat pump that can be suspended in the air and that can effectively utilize the calorific value of circulating water.

[Means to solve the problem]

In the above-mentioned prime mover-driven heat pump, the present invention includes linearly disposing heat exchange pipes into the hot water tank from the top of the hot water tank downwards into which circulated water that has recovered exhaust heat from the prime mover enters. At the same time, a serpentine or spiral hot water storage heat exchanger is disposed at the lower part of the hot water tank, and is connected to the lower end of the heat exchange pipe to output the circulating water from the lower end of the hot water tank to the outside of the hot water tank. ,
The heat transfer volume of this hot water storage heat exchanger is made larger than the heat transfer area of the heat exchanger described above.

[Function] In the prime mover-driven heat pump according to the present invention, when the prime mover is operating, the circulating water that has recovered the exhaust heat enters the hot water tank from the upper part of the hot water tank through the heat exchange pipe. After flowing towards the bottom, it enters the hot water storage heat exchanger located at the bottom of the hot water tank.
The circulating water exits from the lower end of the hot water tank after exchanging heat with the hot water stored inside the tank. Therefore, when the temperature of the hot water stored in the hot water tank is low, the temperature difference between the stored hot water and the circulating water is large, so that the stored water is exchanged mainly at the heat exchange pipe section, that is, at the top of the hot water tank. Heat. Additionally, if the prime mover continues to operate for a certain period of time and the temperature of the stored hot water in the hot water tank increases and the temperature difference between the stored hot water and the circulating water decreases, the heat exchange capacity of the heat exchange pipes will decrease. , the amount of heat exchanged in the hot water storage heat exchanger is increased, the stored hot water is mainly heated from the lower part of the hot water tank where the temperature of the stored hot water is relatively low, and the calorific value of the circulating water can be used effectively. Therefore, in this invention, since the stored hot water is first heated from the upper part of the hot water tank, when discharging a small amount of stored hot water, the prime mover can be operated for a short time, and high-temperature water can be discharged. It is possible to eliminate the operation only for hot water supply, shorten the time, and reduce the number of times. In addition, since the hot water stored in the hot water tank can be heated to a high temperature from the top, the high-temperature hot water dispensing capacity does not depend much on the operating time of the prime mover, and hot water can be drawn out sequentially from the hot water tank that opens at the top of the hot water tank, which is effective. The amount of hot water increases. The heat exchange pipes are arranged linearly in the upper part of the hot water tank, and the heat exchanger for hot water storage is arranged in a meandering or spiral shape only in the lower part of the hot water tank, making this heat exchanger compact and lightweight. This can be easily suspended in the hot water tank.

Furthermore, in this invention, the heat transfer area of the hot water storage heat exchanger is made larger than the heat transfer area of the heat exchange tube, so even when the temperature difference between the circulating water and the hot water stored in the hot water tank is small, the hot water storage heat exchanger The exchanger provides a sufficient amount of heat exchange.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

FIG. 2 shows the cycle system of this embodiment. In Fig. 2, 1 is a prime mover consisting of an internal combustion engine, 2 is a compressor driven by the prime mover 1, 3 is a four-way valve, and 4 is a compressor driven by the prime mover 1.
5 is an indoor heat exchanger, 5 is a throttle mechanism, and 6 is an outdoor heat exchanger. A refrigeration cycle is composed of the compressor 2, the four-way valve 3, the indoor heat exchanger 4, the throttling mechanism 5, and the outdoor heat exchanger 6 as main parts. Due to the changeover, it is now being used for heating and cooling. Further, 7 is a flow path for circulating the cooling water of the prime mover 1 and recovering its heat, 8 is a pump installed in this flow path 7, 9 is a hot water tank, and 10 is a hot water storage heat installed in the hot water tank 9. exchanger, 13 is flow path 7
A hot water control valve such as a thermovalve provided upstream of the hot water tank 9, 14, a bypass flow path 15 connected from the upstream side of the hot water control valve 13, bypassing the hot water tank 9 and downstream thereof; is a resistance portion such as a thin tube provided in the bypass channel 14.

Further, FIG. 3 shows the hot water tank portion of this embodiment, in which a heat exchanger 16 extends vertically from the top to the bottom of the hot water tank 9, and this heat exchange pipe 1
The upper end of the hot water storage heat exchanger 10 is connected to the lower end of the hot water storage heat exchanger 6 . The heat exchanger 10 is formed in a meandering or spiral shape, has a heat transfer area larger than the heat transfer area of the heat exchange tube 16, and is disposed at the lower part of the hot water tank 9 to exchange heat for storing hot water. The lower end of the vessel 10 extends from the lower end of the hot water tank 9 to the outside thereof. Further, a water supply pipe 11 and a hot water supply pipe 12 are opened at the bottom and top end of the hot water tank 9, respectively.

In the prime mover-driven heat pump configured as described above, when the prime mover 1 is operating, the cooling water is circulated through the pipe line 7 by the drive of the pump 8, and the circulating water that has recovered the exhaust heat of the prime mover 1 is used for heat exchange. Heat exchanger 16 and hot water storage heat exchanger 10 exchange heat with the hot water stored in the hot water tank 9 to lower the temperature, and the water is circulated back to the prime mover 1.

In the hot water tank 9, the circulating water that has recovered the exhaust heat of the prime mover 1 is passed through the heat exchange pipe 16 to the hot water tank 9.
After entering from the upper part of the hot water tank 9 and flowing toward the lower part through the heat exchange pipe 16, the hot water enters the hot water storage heat exchanger 10 arranged at the lower part of the hot water tank 9, and the stored hot water inside the hot water tank 9 flows from the lower end of the hot water tank 9. After exchanging heat with the circulating water, it exits the hot water tank. For this reason, immediately after the circulating water enters the hot water tank 9, it starts exchanging heat with the stored hot water in the 16 parts of the heat exchange pipe and gradually lowers its temperature, and the remaining heat is exchanged in the 10 parts of the hot water storage heat exchanger. It turns out. For this reason,
When the temperature of the hot water stored in the hot water tank 9 is low, there is a large temperature difference between the temperature of the circulating water that has recovered the exhaust heat of the prime mover 1, and the heat exchange pipe 16, that is, the hot water tank 9
The internal upper part mainly exchanges heat to heat the stored water.

In addition, if the operation of the prime mover 1 continues for a certain period of time and the temperature of the stored hot water increases and the temperature difference between it and the circulating water decreases, the heat exchange capacity of the heat exchange pipe 16 decreases, so the heat exchanger for hot water storage The amount of heat exchanged in the container 10 increases, and the stored hot water is mainly heated from the lower part of the hot water tank 9, where the temperature of the stored water is relatively low.

Therefore, in this embodiment, since the stored hot water is first heated from the upper part of the hot water tank 9, it is used for purposes other than dispensing a large amount of hot water at once, such as dispensing to a bathtub, i.e., dispensing a small amount of hot water for use in the washroom, kitchen, etc. When dispensing hot water, high-temperature water of 45°C or higher can be dispensed by simply operating the prime mover 1 for a short period of time.In addition, it is possible to eliminate or shorten the operation of the prime mover only for hot water supply as in the past. The number of times of heating can be reduced, and a heat source for an auxiliary heater such as an electric heater or an auxiliary burner can be made unnecessary.

In addition, in this example, the heat exchange of the stored hot water in the hot water tank is by natural convection, so the heat passage rate is relatively small compared to forced convection. If a type with an enlarged heat transfer surface is used, the heat exchange capacity will be increased, and the problem can be easily solved by laying the piping in a straight line from the top to the bottom of the hot water tank instead of meandering.

In addition, the heat exchanger for hot water storage, which is installed only at the bottom of the hot water tank, is small and lightweight, so it is easy to suspend the heat exchanger in the hot water tank against the load, and it is able to resist the vibration of the prime mover. Problems can also be solved.

Furthermore, in this embodiment, the hot water stored in the hot water tank is heated to a high temperature from the top, so the high temperature hot water dispensing ability does not depend much on the operating time of the prime mover.
Hot water can be supplied sequentially from the hot water pipes that open at the top of the hot water tank.
Effective amount of hot water increases. Moreover, since the heat transfer area of the hot water storage heat exchanger is made larger than the heat transfer area of the heat exchange tube, even when the temperature difference between the circulating water and the hot water stored in the hot water tank is small, the hot water storage heat exchanger can A sufficient amount of heat exchange can be obtained, and the amount of heat in the circulating water can be used effectively.

In this embodiment, the circulating water entering the hot water tank 9 is controlled by controlling the hot water control valve 13 at a preset temperature and by restricting the flow rate of the circulating water flowing through the bypass channel 14 by the resistor 15. The temperature can be set to a preset temperature and the circulating water can be circulated. Therefore, 80~ from the top of the hot water tank 9
High-temperature stored water heated to a boiling temperature of 90℃,
It also has the advantage of being able to supply hot water for normal hot water supply loads such as when using the bathroom or in the kitchen.

〔Effect of the invention〕

As explained above, the prime mover-driven heat pump according to the present invention has a heat exchange tube arranged in a straight line in the hot water tank from the top of the hot water tank downwards into which circulating water that has recovered the exhaust heat of the prime mover enters. At the same time, a serpentine or spiral hot water storage heat exchanger is installed in the lower part of the hot water tank, which is connected to the lower end of the heat exchange pipe and delivers the circulating water from the lower end of the hot water tank to the outside of the hot water tank. However, since the heat transfer area of this hot water storage heat exchanger is made larger than the heat transfer area of the above-mentioned exchanger, the following effects can be obtained.

That is, according to this invention, when the temperature of the hot water stored in the hot water tank is low, there is a large temperature difference between the stored hot water and the circulating water, and the stored water is heated mainly by heat exchange in the upper part of the hot water tank. Therefore, when dispensing a small amount of stored hot water, it is possible to dispense high-temperature water by operating the prime mover for a short time, and it is possible to eliminate the operation of the prime mover only for hot water supply, shorten the time, and reduce the number of times. It is possible to eliminate the heat source for auxiliary heating. In addition, since the hot water stored in the hot water tank can be heated to a high temperature from the top, the high-temperature hot water supply capacity does not depend much on the operating time of the prime mover, and hot water can be drawn sequentially from the top of the hot water tank, increasing the effective amount of hot water. do. Moreover, as the temperature of the hot water stored in the hot water tank rises and the temperature difference between the stored water and the circulating water decreases, the heat exchange capacity of the heat exchange pipe section decreases, so the heat exchange capacity of the hot water storage heat exchange section decreases. The amount of exchange increases, the hot water is heated mainly from the lower part of the hot water tank where the storage temperature is relatively low, and the heat transfer area of the hot water storage heat exchanger is made larger than the heat transfer area of the heat exchange tubes, so the hot water storage Since a sufficient amount of heat exchange can be obtained by the heat exchanger, the amount of heat in the circulating water can be used effectively. The heat exchange tubes are arranged in a straight line in the upper part of the hot water tank, and the meandering or spiral heat exchanger for hot water storage is installed only in the lower part of the hot water tank, making it possible to make the heat exchange pipes smaller and lighter. Therefore, it can be easily suspended in the hot water tank, and the problem of vibration caused by the prime mover can be solved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of the hot water tank portion of a conventional motor-driven heat pump, FIG. 2 is a cycle system diagram of a motor-driven heat pump according to an embodiment of the present invention, and FIG. 3 is a longitudinal cross-sectional view of the hot water tank portion of the same. It is a diagram. 1... Prime mover, 2... Compressor, 3... Four-way valve,
4... Indoor heat exchanger, 5... Throttle mechanism, 6... Outdoor heat exchanger, 7... Channel, 9... Hot water tank, 10...
... Heat exchanger for hot water storage, 11 ... Water supply pipe, 12 ... Hot water supply tank, 13 ... Hot water control valve, 14 ... Bypass passage, 15 ... Resistance section, 16 ... Heat exchange pipe. In addition,
In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A refrigeration cycle consisting of a compressor, an indoor heat exchanger, a throttle mechanism, and an outdoor heat exchanger as main parts, a prime mover consisting of an internal combustion engine that drives the compressor, and circulating water that recovers the exhaust heat of this prime mover. In a motor-driven heat pump that is equipped with a hot water tank in which stored hot water is heated to store heat, and a hot water pipe that opens at the upper end of the hot water tank, the above-mentioned heat pump is installed in the hot water tank from the top of the hot water tank downwards. A heat exchange pipe into which circulating water that has recovered the exhaust heat of the prime mover is arranged in a straight line, and the circulating water is supplied from the lower end of the hot water tank connected to the lower end of the heat exchange pipe in the lower part of the hot water tank. A prime mover drive characterized in that a meandering or spiral hot water storage heat exchanger is disposed to take the hot water out of the hot water tank, and the heat transfer area of the hot water storage heat exchanger is larger than the heat transfer area of the heat exchanger. heat pump.