JPS59141752A - Water heater using heat engine - Google Patents

Abstract

PURPOSE:To enable to heat water in a hot-water storing tank at a high thermal efficiency through utilization of engine-cooling water, by covering a liquid-cooled type heat engine by a heat-insulating cover except for auxiliary machinery of the electric system requiring protection from high temperature. CONSTITUTION:In operation of an engine 10, releasing of heat produced by the engine 10 to an engine room 34 is prevented by a cover 38, and cooling water circulated in the engine 10 and an exhaust heat exchanger 40 is heated by the heat accumulated on the inside of the cover 38. Therefore, heat accumulated on the inside of the cover 38 is carried to a heat exchanger 26 in a hot-water storing tank 24 by the cooling water. As for the auxiliary machinery to be protected from high temperature, a starter 44 is, for instance, projected to the outside from the cover 38, and a compressor 12 is similarly projected to the outside for the convenience of repairing and inspection. Further, an air cleaner 14, a case 46 incorporating therein auxiliary machinery of the electric system, etc. are disposed in the engine room 34. With such an arrangement, it is enabled to heat water in the hot-water storing tank by the engine- cooling water at a high thermal efficiency without releasing the heat of an engine to the outside of the system.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water heater using a heat engine, in which water is heated by the coolant of the liquid-cooled heat engine.

A device is being considered that uses a liquid-cooled heat engine to drive the compressor of a heat pump air conditioner, and uses the engine's heat to heat water to obtain hot water, thereby improving the overall thermal efficiency of the entire device. . Also, a device is being considered in which a generator or the like is driven by a liquid-cooled heat engine, and water is heated by the heat of the engine.

When hot water is obtained using the heat of a liquid-cooled heat engine in this way, it is necessary to reduce engine waste heat as much as possible in order to improve overall thermal efficiency. Since a large proportion of engine heat is wasted in the form of exhaust,
Conventionally, an exhaust heat exchanger has been provided to recover exhaust heat, but the amount of heat dissipated outward from the outer wall of the engine is also quite large. Therefore, it has been proposed to house the engine in a closed engine room and provide a heat exchanger for waste heat recovery in the engine room as well (see, for example, Japanese Patent Application No. 57-29815). However, since the temperature difference between the temperature inside the engine room and the refrigerant flowing through the waste heat recovery heat exchanger is relatively small, there is a problem in that the cost is high despite the low heat recovery efficiency. This engine room still houses the accessories that normally come with the engine, so there was also the inconvenience that the electrical system accessories, which needed to be kept from getting too hot, would also end up overheating.

The present invention was made in view of these circumstances, and it is possible to eliminate the need for installing a heat exchanger for waste heat recovery in the engine room.
A water heater using a liquid-cooled heat engine that can efficiently recover waste heat very easily and inexpensively, and also prevent overheating of supplementary equipment housed in the engine room that should be avoided from high temperatures in the electrical system. The i-purpose is to provide.

In order to achieve this object, the present invention includes a liquid-cooled heat engine and engine accessories housed in an engine room; The water heater used was constructed so that at least the engine was covered with a heat insulating cover, except for supplementary items that needed to avoid high temperatures in the electrical system. The present invention will be described in detail below based on the illustrated embodiments.

Figure 1 is an overall configuration diagram of an embodiment of the present invention, Figures 2 and 3 are
The figure shows a partially sectional front view and left side view. 'This embodiment is a combination of a heat pump air conditioner and a water heater. In FIG. 1, reference numeral 10 indicates a liquid-cooled gas engine 1.12 indicates a compressor driven by this engine 10. In FIG. Air is sucked into the engine 10 via an air cleaner 14 and a mixer 16, while gas as a fuel, such as city gas, is supplied via a pressure regulator 15 to a mixer 16, where a mixture of gas and air is created. generated and inhaled into the engine 10.

18 is a four-way switching valve, 19 is an expansion valve, 20 is an indoor heat exchanger, 22 is an outdoor heat exchanger, and these and the compressor 12
A closed loop is formed in which a suitably selected working fluid is enclosed. Each member forming this closed loop and the engine 10 form a known heat pump.

This heat pump operates as follows. During cooling, the switching valve 18 is in the position shown by the solid line in Figure 1, and the compressor 12
The working fluid that has been compressed to a high temperature is transferred to the outdoor heat exchanger 2.
After being cooled and liquefied in step 2, it passes through an expansion valve 19 to a low pressure and is vaporized in an indoor heat exchanger 20, removing indoor heat. Then, the cycle of being compressed again by the compressor 12 is repeated.

During heating, the switching valve 18 is placed in the imaginary line position in Figure 1, and the high-temperature working fluid compressed by the compressor 12 warms the room in the indoor heat exchanger 20, passes through the expansion valve 19, and becomes low pressure. After that, it vaporizes and expands in the outdoor heat exchanger 22 and takes in heat from the outside air using the latent heat of vaporization at that time. This working fluid then returns to the compressor 12 and repeats the above cycle.

In Fig. 1, 24 is a hot water storage tank, which includes a heat exchanger 26.
A coolant for the engine 10 is circulated through the heat exchanger 26. That is, the water in the hot water tank 24 is heated by the waste heat of the engine 10. Note that 28 is a valve for injecting water into the hot water tank 24, and 30 is a valve for discharging hot water. Further, reference numeral 32 denotes an auxiliary burner that uses gas as fuel, and is ignited when the water temperature in the hot water storage tank 24 drops excessively to maintain the water temperature at an appropriate level.

In Fig. 2.3, 32 is a rectangular cylindrical case, and an engine room 34 is formed in the lower part of this case 32, above which is the hot water tank 24, and further above that is an outdoor heat exchanger 22-. are accommodated in each. Inside this case 32, each device except the indoor heat exchanger 20 shown in FIG. 1 is housed. A fan 36 is disposed above the outdoor heat exchanger 22 to guide outside air into the heat exchanger 22 at a strong force of 11J. The engine room 34 houses the engine 1o and engine accessories. Among these supplements, those that become hot are housed in the heat insulating cover 38 together with the engine 10. That is, an exhaust heat exchanger 40 that recovers exhaust heat, an auxiliary oil tank 42 that communicates with a lubricating oil reservoir at the bottom of the crankcase, and the like are housed within the cover 38. The starter motor 44 is exposed outside the cover 38 through a window 46 provided in the cover 38 to avoid high temperatures. Further, for convenience of maintenance and inspection, the compressor 12 is similarly installed so as to protrude from the cover 38 into the engine room 34. As shown in FIG. 3, one side of the cover 38 serves as a removable lid plate 38a-, and the portion of the case 32 that forms one side of the engine room 34 of the side facing the lid plate 38a similarly serves as a removable lid plate 38a-. It is a removable cover plate 34a. For this reason, the cover plate 34
By removing a + 38a, the engine 10 can be inspected.

Inside this engine room 34 are accessories that need to be protected from heat, such as electrical system accessories such as an electronic ignition system, ignition coils, various control circuits, and an air cleaner 2.
4, a regulator 15, a mixer 16, etc. are housed. Note that these electrical system supplements are housed in a case 46 (FIG. 2).

Intake air is guided to the share cleaner 14 through an intake pipe 48.

The exhaust gas passes through the exhaust heat exchanger 40 and the exhaust muffler 50 and is discharged to the outside of the case 32 from the exhaust port 52. Note that the coolant that circulates between the engine 10 and the heat exchanger 26 is guided to the exhaust heat exchanger 40, and the exhaust heat is recovered into the coolant and used to heat the water in the hot water tank 24. . In Figure 2, 5
Reference numeral 4 indicates an inlet/outlet for the coolant flowing through the engine 10 and the exhaust heat exchanger 40, and 56 indicates the heat exchanger 2 in the hot water storage tank 24.
These are the inflow and outflow ports for the cooling liquid flowing into the port 6.

While engine 10 is currently operating, engine 1 oo
m is prevented from dispersing into the engine room 34 by the cover 38, and the temperature inside the cover 38 increases. This cover 3
8 heats the coolant circulating in the engine 1o and the exhaust heat exchanger 40, and this coolant cools the hot water tank 2.
4 to the heat exchanger 26 in the 4. Therefore, less heat is dissipated into the engine room 34, and the waste heat of the ennon 1o can be used effectively. In addition, since the supplements that do not like high temperatures are placed in traps outside the cover 38, these supplements will not be harmed by overheating.

In the embodiments described above, the compressor 12 is made to protrude from the cover 38 for reasons of inspection and maintenance, but in the present invention, the compressor 12 can also be housed within the cover 38 together with the engine 10. FIG. 4 is a partially sectional front view showing such an embodiment. In this figure, the same parts as in FIG. 2 are denoted by the same reference numerals, so their description will not be repeated. According to this embodiment, the heat emitted by the compressor 12 can also be absorbed by the cooling liquid within the cover 38, so that the thermal efficiency is further improved. In each embodiment of 4° or more, not only the engine 10 but also the exhaust heat exchanger 40 are housed within the heat insulating cover 38, but other supplementary items such as the exhaust silencer 50 that become hot are also housed within the cover 38. Of course, it may be accommodated. On the other hand, it goes without saying that the desired effects of the present invention can also be obtained even if only the engine 10 is accommodated within the cover.

As described above, the present invention covers at least the liquid-cooled engine with a heat insulating cover in the engine room, excluding the electrical system supplements that need to avoid high temperatures. The water is trapped inside the cover without escaping, and can be used to heat the water in the hot water storage tank using the cooling liquid. Therefore, the engine waste heat can be used effectively,
Thermal efficiency can be improved. Furthermore, since the auxiliary items that should be kept away from the high temperatures of the electrical system are placed outside the cover, these auxiliary items can be protected from the heat. It goes without saying that heat-resistant electrical system accessories such as spark plugs may be installed inside the cover.

[Brief explanation of the drawing]

Figure 1 is an overall configuration diagram of an embodiment of the present invention, Figures 2 and 3 are
The figures are a partially sectional front view and a left side view, and FIG. 4 is a partially sectional front view of another embodiment. 10...Engine, 24...Hot water tank, 34...
・Engine room, 38...Insulating cover. Patent, Applicant: Small Gas Cooling Technology Research Association Agent Patent Attorney Yama 1) Yu Moon Figure 2 Figure 3

Claims (1)

[Claims] A liquid-cooled heat engine and engine auxiliaries are housed in the engine room, and the coolant of the engine is circulated to a hot water storage tank to heat water, except for the auxiliaries that need to avoid high temperatures in the electrical system. A water heater using a heat engine, characterized in that the engine is covered with a heat insulating cover.