JPH0362984B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is an engine-driven heat pump that is capable of cooling and heating heat loads such as greenhouses. In the exchange medium circulation circuit, a heat exchanger using engine exhaust heat is installed on the condenser outlet side, consisting of a first exchanger using engine cooling water as a heat source and a second heat exchanger using engine exhaust gas as a heat source. This article relates to an engine-driven heat pump equipped with an engine-driven heat pump.

[Conventional technology]

One of the conventionally well-known engine-driven heat pumps of this type is the
There is one shown in Figure 1 in Publication No. 66071, and the one shown here is a first one that uses engine cooling water as a heat source on the condenser outlet side in the hot water heat exchange medium circulation circuit to the condenser. It was equipped with a heat exchanger and a second heat exchanger using engine exhaust gas as a heat source, and these heat exchangers, a condenser, and a heat load were simply connected in series with piping.

[Problem that the invention seeks to solve]

As mentioned above, a heat pump that is basically a condenser, a heat exchanger, and a heat load connected in series via piping circulates well water for heat exchange to the evaporator, and directs hot water in the hot water circuit to the heating load. When switching between a heating state in which well water is circulated to the condenser and a cooling state in which well water for heat exchange is circulated to the condenser and chilled water in the chilled water circuit is circulated to the cooling load. The amount of well water circulated as a hot water heat exchange medium through the exhaust heat heat exchanger is relatively small (for example, 200/ml).
However, during heating, the amount of hot water heat exchange medium circulated from the engine-based heat exchanger to the heating load is reduced to the amount of well water circulated to the evaporator. In order to maintain the heat balance between
I had to.

Therefore, the amount of hot water heat exchange medium circulating through the engine exhaust heat heat exchanger is larger during heating than during cooling, so the temperature of the hot water heat exchange medium during cooling and the temperature during heating are different from the temperature of the hot water heat exchange medium during heating. As long as it is within a range that does not affect the heat transfer characteristics (heat passage resistance) of heat exchangers that utilize waste heat, the amount of heat exchanged will increase as the amount of circulation increases, and the temperature of the engine coolant will decrease. was larger than the setting, causing engine overcooling.

An object of the present invention is to provide a system that can prevent engine overcooling during heating by adding a simple mechanism.

[Means for solving problems]

The characteristic configuration according to the present invention is that a bypass circuit is provided that directly connects the condenser discharge side and the heat load, and a valve is provided in this bypass circuit to branch and flow hot water from the condenser into the bypass circuit. During heating, in which well water for heat exchange is circulated to the condenser and hot water in the hot water circuit is circulated to the heating load, the valve is opened and the well water for heat exchange is circulated to the condenser. The valve is closed during cooling when the cold water in the cold water circuit is circulated toward the cooling load, and its effects are as follows.

[Effect]

In other words, by keeping the valve open during heating, a portion of the heat exchange medium discharged from the condenser can be circulated directly to the heat load via the bypass circuit. The amount of heat exchange medium circulated through the heat utilization heat exchanger can be made the same as the amount of circulation during cooling, and at the time of cooling, the valve can be closed and only a predetermined amount of circulation can be circulated as before. Moreover, since the installation part of the bypass circuit is directly connected to the heat load from the condenser outlet, the circulation amount in the condenser can be maintained at a predetermined amount, and the heat balance between the condenser and evaporator will not be disrupted. do not have.

〔Effect of the invention〕

As a result, it is possible to avoid the overcooling phenomenon of the engine during heating, and to do so, it is only necessary to add a bypass circuit with a valve to the condenser outlet side, which requires no installation modification. It is also easy to change.

〔Example〕

As shown in FIGS. 1 and 2, for a refrigerant circulation circuit equipped with a condenser 1, an expansion valve 2, an evaporator 3, and an engine E-driven compressor 4, a hot water heat exchange medium is supplied to the condenser 1. In the circulation circuit 5, on the outlet side of the condenser 1, engine exhaust heat is collected from a first heat exchanger 6 whose heat source is engine cooling water, which has exchanged heat with a second heat exchanger 7 whose heat source is engine exhaust gas. In addition to the heat exchanger 8 used, a cold water heat exchange medium circulation circuit 9 is provided for the evaporator 3. A well water circulation circuit 10 and a heat load circulation circuit 11 of a greenhouse or the like are placed in communication with these cold and hot water heat exchange medium circulation circuits 9 and 5, respectively, and as shown in FIG.
While circulating hot water from condenser 1 to 2,
A heating state in which well water is circulated through the evaporator 1, and a second
As shown in the figure, a cold water heat exchange medium circulation circuit 5, a heat load circulation circuit 11 for greenhouses, etc., and a well water circulation circuit 1.
The heat pump is configured to be able to switch to a cooling state in which cold water is circulated through the heat load 12 by communicating the hot water heat exchange medium circulation circuit 9 with the hot water heat exchange medium circulation circuit 9.

The amount of hot water circulated to the heating load 12A in the heating state is 350/min, and the amount of cold water circulated to the evaporator 3 side is 200/min. Also, the amount of cold water circulated for the cooling load 12B in the cooling state is
300/min, and the hot water (well water) circulation rate to the condenser 1 side is 200/min. The temperature drop after heat exchange with the heating load 12A of the hot water in the heating state is 5°C, and the cooling load 12A of the cold water in the cooling state is 5°C.
The temperature increase after heat exchange with B is 11°C.

A bypass circuit 13 is provided that directly connects the discharge side of the condenser 1 and the heat load 12, and an electromagnetic valve 14 is provided in the bypass circuit 13 to allow hot water from the condenser 1 to flow into the bypass circuit. When opened, the amount of hot water circulating to the engine exhaust heat utilization heat exchanger 8 can be reduced to the amount of circulation during cooling (200/min), and overcooling of the engine E can be prevented. Further, during cooling, the electromagnetic valve 14 is closed so that the entire amount of hot water from the condenser 1 flows into the engine exhaust heat utilization heat exchanger 8.

[Another example]

The valve 14 may be a manual stop valve.

The engine exhaust heat utilization heat exchanger 8 exchanges heat with the hot water from the condenser 1 in a first heat exchanger 6 using engine cooling water as a heat source, and then in a second heat exchanger 7 using engine exhaust gas as a heat source. Both heat exchangers 6 and 7 may be configured to exchange heat with hot water.

[Brief explanation of drawings]

The drawings show an embodiment of an engine-driven heat pump according to the present invention, with FIG. 1 being an overall configuration diagram showing a heating state, and FIG. 2 being an overall configuration diagram showing a cooling state. 1... Condenser, 3... Evaporator, 5... Hot water heat exchange medium circulation circuit, 8... Heat exchanger using engine exhaust heat, 12... Heat load, 12A... Heating load, 12B... Cooling load, 13...bypass circuit, 14...valve.

Claims (1)

[Claims] 1 An engine-driven heat pump in which a heat exchanger 8 that utilizes engine exhaust heat is interposed on the outlet side of the condenser 1 in a hot water heat exchange medium circulation circuit 5 to the condenser 1. A bypass circuit 13 is provided to connect the discharge side and the heat load 12, and a valve 14 is provided in the bypass circuit 13 to branch the hot water from the condenser 1 into the bypass circuit 13. During heating, in which well water for heat exchange is circulated and hot water in the hot water circuit is circulated toward the heating load 12A, the valve 14 is opened, and the condenser 1 is The engine-driven heat pump is configured to close the valve 14 during cooling, in which well water is circulated and chilled water in the chilled water circuit is circulated toward the cooling load 12B.