JPS6256427B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a heating device that performs heating by driving a compressor using a heat engine powered by combustion energy such as city gas or kerosene. .

[Prior art]

BACKGROUND ART In recent years, from the viewpoint of energy conservation, there has been active development of air-conditioning devices that perform air-conditioning and heating using heat pumps that use combustion energy such as city gas or kerosene.
This heat pump uses combustion energy to operate the engine, etc., which drives the heat pump compressor to perform heating and cooling, and the exhaust heat of the engine during heating can be used for heating.
It is more energy efficient than an electric heat pump.

[Problem that the invention seeks to solve]

However, conventional engine-driven exhaust heat recovery heat pumps have the following problems.

In other words, in conventional heat pumps, when the outside air temperature is very low or when it snows, the evaporation temperature in the outside air side heat exchanger decreases, the specific volume of refrigerant gas increases significantly, and the amount of refrigerant circulated is drastically reduced, resulting in heating. The capacity may drop abnormally and frost may form, making it unusable. In such a case, not only will the heat pump not be able to heat the load hot water, but the heat pump load will be so small that the engine will not be able to rotate at the rated speed, and if the compressor is stopped, the exhaust heat will be It is not possible to use the engine, and even if only the engine is rotated, there is no load and the engine is idling.
The amount of exhaust heat also decreases, and in the end, the heating capacity is not only due to the decrease in the heat of the outside air that should be pumped, but also due to a combination of the decrease in heat pump heating due to the inability of the heat pump to operate, and the decrease in the amount of exhaust heat from the engine. The problem was that the heating capacity was severely reduced.

In addition, as a countermeasure against such an abnormal drop in outside temperature, the technology disclosed in Publication of Utility Model Publication No. 51-35632 is also known. The use of heat is limited to heating the evaporator via outside air, which causes large heat radiation loss, and does not heat the interior air, which is the load fluid, with exhaust heat. The problem is that the amount of heating of the load fluid is small, and the engine exhaust heat is not used when the outside temperature is normal, so exhaust heat recovery is not performed well. It was hot.

There is also a system like the one shown in Utility Model Publication No. 52-22735, but when the outside temperature is normal, heat is not pumped up from the outside air, and the amount of heat recovered is small. If the engine's exhaust heat drops abnormally, the use of engine exhaust heat is limited to heating the heat pump's evaporator, without heating the indoor air, which is the load fluid, and at the same time pumping heat from the outside air. The problem was that the amount of heating of the indoor air was small.

Furthermore, in order to solve these problems, it has been proposed to install an auxiliary evaporator in parallel with the outside air side heat exchanger, but the amount of refrigerant led to the auxiliary evaporator is larger than necessary, resulting in As a result, the evaporation temperature and evaporation pressure rise, and the temperature difference with the outside air disappears, leading to insufficient heat intake from the outside air, resulting in a decrease in the coefficient of product production (COP).

The present invention solves the above-mentioned problems of the conventional ones, allows the heat pump cycle to operate even when the outside temperature drops abnormally, prevents frost formation, heats the load fluid, and also operates using waste heat. Heats the fluid to achieve the best COP, and compensates for the lack of heat by increasing the rotational speed to prevent a decrease in heating capacity, and
The object of the present invention is to provide a heating device that heats a load fluid using exhaust heat from a heat engine together with a heat pump even when the outside air temperature is normal, thereby improving heat utilization efficiency.

[Means for solving problems]

The present invention provides a heat pump consisting of a compressor driven by a heat engine, an outside air side heat exchanger, a load side heat exchanger, an expansion device, and a refrigerant path connecting these devices, and a heat pump that recovers exhaust heat from the heat engine. an auxiliary evaporator disposed in parallel to the outside air side heat exchanger in the refrigerant path; and a heating device including a load fluid to the exhaust heat recovery device and the load side heat exchanger. a load fluid path to guide the load fluid or the waste heat medium to the auxiliary evaporator, an outside air temperature detection device that directly or indirectly detects the outside temperature, and the obtained detected value as a set value. a flow rate ratio control device that compares and controls a refrigerant flow rate ratio to the outside air side heat exchanger and the auxiliary evaporator based on the detected value when the outside air temperature is below a predetermined abnormally low temperature; a load detection device that detects the load; and a rotation device that compares the detected value obtained with a set value and controls the rotation speed of the heat engine based on the detected value when the load is excessive. This heating device is characterized by being equipped with a numerical control device.

〔Example〕

The present invention will be explained with reference to the drawings based on examples.
In the cooling/heating device shown in the drawing, 1
3 is a compressor, 3 is an outside air side heat exchanger, 7 is a load side heat exchanger, 9 is an expansion valve as an expansion device, and a heat pump is formed by connecting each device with a refrigerant path. Note that a four-way valve 2, an expansion valve 6, and check valves 4 and 8 are provided in the refrigerant path to enable switching to cooling operation. 5 is a receiver.

The heat pump is further provided with an auxiliary evaporator 23 in parallel with the outside air side heat exchanger 3. In this embodiment, the refrigerant path connecting the refrigerant path between the receiver 5 and the expansion valve 9 and the outside air side heat exchanger 3 and the four-way valve 2 is a bypass path that bypasses the outside air side heat exchanger 3. Branched out as 37,
A bypass valve 21 and an expansion valve 2 are provided in the bypass path 37.
2 and an auxiliary evaporator 23 are provided.

Reference numeral 25 denotes an engine used as a heat engine for driving the compressor 1. For example, a jacket 1 is used as an exhaust heat recovery device for recovering exhaust heat from the engine 25.
1 and an exhaust gas heat exchanger 14.

A load fluid path that bypasses the load side heat exchanger 7 is branched into a load fluid path that leads the load fluid to the load side heat exchanger 7 as a bypass path 19 . The bypass path 19 connects the jacket 11 of the engine 25, the coolant cooler 10, and the exhaust gas heat exchanger 1.
4, an auxiliary heat source path 16 that bypasses the coolant cooler 10 and passes through the auxiliary evaporator 23 is branched. 12
is a pump, 13 is a three-way valve, 15, 17, 18 are three-way switching valves, and 20 is a solenoid valve.

The heating device formed as described above further includes an outside temperature detection device that directly or indirectly detects the outside temperature, and compares the obtained detected value with a set value, and determines whether the outside temperature is below a predetermined abnormally low temperature. , a flow rate ratio control device that controls the refrigerant flow rate ratio to the outside air side heat exchanger 3 and the auxiliary evaporator 23 based on the detected value, and a load detection device that detects the load. A rotation speed control device is provided that compares the detected value with a set value and controls the rotation speed of the engine 25 based on the detected value when the load is excessive. The outside temperature detection device is a device for detecting physical quantities related to outside air temperature, such as outside air temperature (temperature detector 27), evaporation pressure (pressure detector 28), or evaporation temperature (temperature detector 30), that is, a device that directly detects outside temperature. Alternatively, a detection device that detects indirectly is used, and the load detection device only needs to detect the load, that is, the amount of load, and the inlet temperature of the load fluid (hot water),
Detection devices such as outlet temperature (temperature detector 26) or inlet/outlet temperature difference are used. The flow ratio control device consists of a control mechanism and a bypass valve 21, and the rotation speed control device consists of a control mechanism and a rotation speed adjustment device 38. The control mechanism of the flow rate ratio control device and the control mechanism of the rotation speed control device compare the detected value obtained by the outside temperature detection device in the former and the load detection device in the latter with a set value, and the former compares the detected value obtained by the outside temperature detection device with a set value. In the latter case, when the load is excessive when the temperature is below low temperature, the flow rate ratio or the rotation speed is controlled based on the detected value. That is, the signal from the detection device is compared with a predetermined setting value, and a signal corresponding to the input signal is output according to feedback or a predetermined program, and this output signal is used to activate the bypass valve. 21 or the rotational speed adjusting device 38 to a predetermined flow rate ratio or rotational speed. As the rotation speed control device, for example,
A control mechanism that converts a temperature signal of the detected load temperature into a voltage signal, and a rotation speed adjustment device 38 that sends this voltage signal to a governor and operates a throttle valve of the engine 25 by a governor motor are provided. It is controlled so that it remains constant.

Therefore, the normal heat pump cycle is similar to that of a general electric air source heat pump.
In other words, during summer cooling, the refrigerant flows through the compressor 1 → four-way valve 2 → outside air side heat exchanger 3 (operates as a condenser)
→ Check valve 4 → Receiver 5 → Expansion valve 6 → Load side heat exchanger 7 (operates as an evaporator) → Four-way valve 2 →
The cold water is circulated in the order of the compressor 1 and cooled in the load side heat exchanger 7.

During heating, the four-way valve 2 is switched to change the refrigerant path, compressor 1 → four-way valve 2 → load side heat exchanger 7 (acts as a condenser) check valve 8 → receiver 5 → expansion valve 9 → outside air side heat The hot water is circulated in the order of exchanger 3 (acting as an evaporator) → four-way valve 2 → compressor 1, and the hot water is heated in the load-side heat exchanger 7.

On the other hand, the cycle on the engine 25 side is as follows. During cooling, the exhaust heat from the jacket 11 is cooled by the outside air by the cooling medium cooler 10.
That is, the coolant that has been heated by cooling the jacket 11 is sucked by the pump 12, sent to the coolant cooler 10, and cooled there. The water is then supplied to the jacket 11 again via the three-way valve 13. The temperature of the cooling medium is detected by the temperature detector 24, the bypass amount of the exhaust gas heat exchanger 14 is controlled by the three-way valve 13, and cooling water at an appropriate temperature is supplied to the jacket 11.

During heating, the three-way switching valves 15, 17, and 18 are switched, and the solenoid valve 20 is opened so that the exhaust heat from the engine 25 is used to heat the hot water. That is, the cooling water (part of the load hot water) heated by cooling the jacket 11 is sucked into the bypass path 19 by the pump 12, passes through the three-way switching valve 15, the auxiliary heat source path 16, and the auxiliary evaporator 23, and then , sent to the exhaust gas heat exchanger 14 via the three-way switching valve 17,
It is further heated by exhaust gas.

The heated hot water joins the hot water from the load-side heat exchanger 7 via the three-way switching valve 18, and is used for heating the load. Solenoid valve 2 handles the load hot water when the temperature drops.
0, and the jacket 11 is cooled again. Note that when the load is light, the temperature of the hot water supplied to the jacket 11 may be too high, so this supply temperature is detected by the temperature detector 24 and adjusted by the three-way control valve 13 so that the temperature is approximately constant. .

Since the heating load is normally smaller than the cooling load, the rotational speed of the engine 25 may be set lower during heating than during cooling.

In this way, as will be described later, it is easy to provide a margin for increasing the rotational speed at abnormally low temperatures.

During heating, when the outside temperature is normally high enough, the bypass valve 21 is closed, the entire amount of refrigerant is guided to the outside air side heat exchanger 3, and the heat source of the heat pump is taken only from the outside air. Since the heating capacity decreases when the outside temperature drops to a certain degree, the rotation speed of the engine 25 is automatically controlled by the rotation speed control device 38 based on the detected value of the temperature of the load fluid. and let it rise. As described above, even in a device in which the rotational speed during heating is set lower than the rotational speed during cooling, in this case the rotational speed is increased above the set rotational speed.

Furthermore, when it is detected that the outside temperature is lower than a predetermined abnormally low temperature, for example, a temperature at which frost frequently appears on the outside air side heat exchanger 3, the flow rate is increased to prevent frost formation. The ratio control device operates,
By controlling the load ratio of the loads borne by the outside air side heat exchanger 3 and the auxiliary evaporator 23, the heat required for the heat pump is taken in from the outside air with priority, thereby improving the product growth coefficient under the outside air temperature condition. By taking the insufficient heat from the hot water in the auxiliary evaporator 23, and using this heat to perform the evaporation action, the load hot water is heated by the heat pump formed, and at the same time, the load hot water is heated by the engine exhaust heat. do. Therefore, the heat that is still insufficient due to the excessive load is supplemented by directly or indirectly using the surplus output or exhaust heat obtained by increasing the rotation speed of the engine 25 from the normal speed using the rotation speed control device. take in.

If the outside air temperature drops extremely abnormally, the bypass valve 21 will be fully open, and most of the load will be borne by the auxiliary evaporator 23. An on-off valve may also be provided in the path of the outside air side heat exchanger 3.

As described above, the flow rate ratio is controlled by the flow rate ratio control device so that the required amount of heat is taken in from the outside air with priority, the insufficient amount is taken in from the hot water in the auxiliary evaporator 23, and the insufficient amount is further taken in by increasing the rotation speed of the engine 25. By taking in the heat, it is possible to prevent frost formation, perform a good heating cycle operation of the COP, and prevent a decrease in the heating capacity. In other words, in order to achieve the best COP, it is better to take in as much heat as possible from the outside air, but if the outside temperature is low, abnormal frost formation will occur, so it is necessary to keep the temperature at the lowest level without causing abnormal frost formation. The refrigerant flow rate is distributed between the outside air side heat exchanger 3 and the auxiliary evaporator 23.

An example of a control method will be explained. Although various control methods are shown in the drawings, this does not mean that they are all provided or operated at the same time, but are drawn on the same drawing for convenience, and each control method may be used alone or in combination as appropriate. It is used.

The control to adapt the heating capacity according to the load by the rotation speed control device uses, for example, the temperature detector 26 of the hot water temperature in the return path as the load detection device, and based on the signal, the control mechanism 39 and the rotation speed adjustment device 38 controls the rotational speed of the engine 25 to keep the return hot water temperature almost constant.

The load ratio control of the load between the outside air side heat exchanger 3 and the auxiliary evaporator 23, that is, the flow rate ratio control of both, by the flow rate ratio control device is performed by controlling the flow rate of the bypass valve 21, and is performed, for example, in the following manner. be exposed.

When the temperature detector 27 is used as an outside temperature detection device, the temperature detector 30 is controlled by the control mechanism 40, and when the pressure detector 28 is used, the control mechanism 42
When using the bypass valve, the control mechanism 41 controls the bypass valve so that the evaporation pressure or evaporation temperature reaches a predetermined value that will give an evaporation temperature that does not cause frosting relative to the outside air temperature at that time and will maximize the COP. 21 flow rate control is performed.

Alternatively, as another control method, control may be performed using a preset program. For example, a program between the outside air temperature (temperature detector 27) and the opening degree of the bypass valve 21, evaporation pressure (pressure detector 27), etc.
8) and the opening degree of the bypass valve 21, a combination of signals between the load (temperature detector 32, engine speed detector or cooling water temperature detector 31) and outside air temperature (temperature detector 27) and the opening degree of the bypass valve 21 (control mechanism 33
or 34), load (temperature sensor 32, engine speed sensor or cooling water temperature sensor 3
1), evaporation pressure (pressure detector 29), and the opening degree of the bypass valve 21 using a program (using the control mechanism 35).

Alternatively, as another control method, the temperature difference between the outside air temperature (temperature detector 27) and the evaporation temperature (temperature detector 30) is detected, and the bypass valve 21 is activated by the control mechanism 36.
The opening degree may be controlled by a program or so that the evaporation temperature or evaporation pressure becomes a predetermined value as described above. This method is more preferable than other methods.

The various outside temperature detection devices (temperature detectors 27, 31, pressure detectors 28, 29) described above detect outside temperature-related physical quantities related to outside air temperature, that is, directly or indirectly detect outside temperature. It is a thing,
In addition, for example, the suction pressure of the compressor 1 (approximately the same as the evaporation pressure) may be detected.

In addition to the above, the heat source of the auxiliary evaporator 23 may be direct exhaust heat, or the heat exchanger 7 on the load side.
It may be heated by hot water at the inlet or outlet of the condenser. That is, it is also possible to directly introduce the waste heat medium or hot water to the auxiliary heat source path 16.

The above embodiment is configured and operates as described above, so that even if the outside temperature drops abnormally, frost will not form on the outside air side heat exchanger 3, or the COP will decrease, resulting in a decrease in capacity. Moreover, it has the advantage of not requiring special heating equipment such as a boiler.

Although this device is a heating device according to the purpose of the invention, it may also be a heating and cooling device as in the illustrated embodiment. However, it has nothing to do with a cooling-only machine, which is a type of heat pump in a broad sense.

〔Effect of the invention〕

According to the present invention, it is possible to provide a heating device having the following particularly remarkable effects.

(1) When the outside temperature drops abnormally, (a) the load fluid and refrigerant are simultaneously introduced into the auxiliary evaporator inserted in parallel with the outside air side heat exchanger used in the case of normal outside temperatures; None, the refrigerant is heated by the load fluid and evaporated to generate a refrigerant gas with a small specific volume, preventing frost formation and enabling the operation of the heat pump cycle. The auxiliary evaporator heats the load fluid and provides the load fluid with a larger amount of heat than the heat removed by the auxiliary evaporator, effectively heating the load fluid.

(b) Since a part of the load fluid is directly heated by the exhaust heat of the heat engine, the amount of heating of the load fluid is further increased, and less recovered heat is dissipated.

(c) As shown in (a), by enabling the operation of the heat pump cycle, the heat engine is operated at or near the rated load rather than in an idling state, so the amount of waste heat is large, and in combination with (a) The amount of heating of the load fluid becomes large.

(d) At the same time that the auxiliary evaporator heats the load fluid, it is also possible to pump up heat from the outside air in the outside air side heat exchanger, which can increase the amount of heating of the load fluid in the heat pump.

(e) Increase the rotation speed of the heat engine to increase the capacity of the heat pump, that is, the amount of heat pumped,
This increases the amount of heat generated by waste heat.

(f) In this way, the load fluid is heated as much as possible to prevent a decrease in heating capacity.

(g) Furthermore, frost formation can be prevented and stable operation can be achieved.

(h) COP can be maintained at the best value.

(2) When the outside temperature is normal (a) Heat is pumped up from the outside air to activate the heat pump cycle to heat the load fluid, and at the same time heats a part of the load fluid using the exhaust heat of the heat engine to generate heat. It is possible to improve the utilization rate.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Compressor, 2...Four-way valve, 3...Outside air side heat exchanger, 4...Check valve, 5...Receiver, 6...Expansion valve, 7...Load side heat exchanger, 8...Check valve, 9...
Expansion valve, 10... Cooler, 11... Jacket, 12
...Pump, 13...Three-way valve, 14...Exhaust gas heat exchanger, 15...Three-way switching valve, 16...Auxiliary heat source path, 1
7... Three-way switching valve, 18... Three-way switching valve, 19... Bypass path, 20... Solenoid valve, 21... Bypass valve, 2
2... Expansion valve, 23... Auxiliary evaporator, 24... Temperature detector, 25... Engine, 26, 27... Temperature detector,
28, 29... Pressure detector, 30, 31, 32... Temperature detector, 33, 34, 35, 36... Control mechanism,
37... Bypass path, 38... Rotation speed adjustment device, 3
9, 40, 41, 42...control mechanism.

Claims (1)

[Scope of Claims] 1. A heat pump consisting of a compressor driven by a heat engine, an outside air side heat exchanger, a load side heat exchanger, an expansion device, and a refrigerant path connecting these devices;
an auxiliary evaporator disposed in the refrigerant path in parallel with the outside air side heat exchanger; a load fluid path that leads the load fluid to the load side heat exchanger; an auxiliary heat source path that leads the load fluid or the waste heat medium to the auxiliary evaporator;
An outside temperature detection device that directly or indirectly detects the outside temperature, and compares the obtained detected value with a set value, and when the outside temperature is below a predetermined abnormally low temperature, a flow rate ratio control device that controls a refrigerant flow rate ratio to the outside air side heat exchanger and the auxiliary evaporator; and a load detection device that detects the load;
A rotation speed control device that compares the obtained detected value with a set value and controls the rotation speed of the heat engine based on the detected value when the load is excessive. heating equipment. 2. The device according to claim 1, wherein the load detection device is a temperature detector that detects the temperature of the load fluid.