JPS6396457A - Heat pump device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat pump device, and particularly to pressure measurement thereof.

[Conventional technology]

Conventionally, as a device of this kind, for example, the Mitsubishi Electric Refrigeration Handbook [No.
There was something shown in the figure. In fig.

+1) is the compressor, (21 is the condenser, and (3) is the first pressure reducing device.

For example, a temperature-type expansion valve, (4: evaporator, (51) temperature-sensitive cylinder of the temperature-type expansion valve (3), (6a) a high-pressure side pressure switch provided at the outlet of the compression @ (1), (6b) ) is the low-pressure side pressure switch installed at the inlet of the compressor fi+.The pressure switch C6a') and (sb) are 1, for example, Refrigeration and Air Conditioning Handbook, 4th edition, Basics 1 (Japan Refrigeration Association, published 1986.5). This is a generally known pressure switch as described in .30).Furthermore, a heat medium 1 such as a refrigerant is sealed in the pipes that connect all these.

Next, the operation will be explained. High-pressure refrigerant gas V1.1) discharged by the compressor (1): radiates heat in the condenser (2), liquefies it, and flows into the thermostatic expansion valve (3). The refrigerant flowing into the thermostatic expansion valve (3) is depressurized, becomes low temperature and low pressure, absorbs heat in the evaporator (4), is gasified, and is sucked into the compressor +1) again, forming a circulation cycle.

In addition, a high pressure switch (6a) is installed on the discharge side of the compressor (1).
), the switch operates and the pressure can be detected when the discharge pressure of the compressor (1) increases beyond the set high pressure. Similarly, the suction pressure of the compressor (1) is configured so that when the suction pressure decreases below the set low pressure, a switch is operated and the pressure can be detected. Based on the detected pressure, the rotational speed of the fans of the condenser [2] and the evaporator (4), the rotational speed of the compressor (1), etc. are controlled.

[Problem that the invention seeks to solve]

In the above-mentioned heat pump equipment, a pressure switch or pressure sensor must be installed to detect the pressure, and if multiple pressures need to be detected, multiple pressure switches or pressure sensors must be installed. become very expensive. Also.

In the case of a pressure switch, this is because it detects based on the set pressure.

Problems such as the impossibility of detecting continuous pressure changes.

Does this invention have such problems? The purpose of this invention is to provide at a low cost a heat pump device that detects continuous pressure changes and controls its operation.

[Means for solving problems]

The heat pump device according to the present invention includes piping that connects a high pressure side from a compressor outlet to a first pressure reducing device inlet and a low pressure side from a first pressure reducing device outlet to the compressor inlet via a second pressure reducing device; A cooling means for cooling the heat medium flowing into the second pressure reducing device from the high pressure side of the piping, and a bypass means branching from the high pressure side of the piping and flowing from the middle part of the cooling means to the inlet of the second pressure reducing device. , a first temperature sensor that detects the entire temperature of the high-pressure heat medium from the position where the heat medium flows into the bypass means to the inlet of the second pressure reducing device on the downstream side, and a first temperature sensor that detects the entire temperature of the high pressure side heat medium at the outlet of the second pressure reducing device A second temperature sensor is provided for detecting the temperature of the medium, and the pressure on the high pressure side and the pressure on the low pressure side of the compressor are determined by the second temperature sensor and the second temperature sensor, respectively.

[Effect]

In this invention, the temperature sensor is cheaper than a pressure sensor or pressure switch, and can detect continuous temperature changes of the target object. It is possible to estimate the pressure that has a predetermined relationship with the saturation temperature, and to control the operation of the heat pump device using the saturation temperature as a control signal.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, the high pressure side from the +61Fi compressor (1) outlet to the thermostatic expansion valve, i.e. the first pressure reducing device (3) inlet, and the low pressure side from the thermostatic expansion valve (3) outlet to the compressor (1) population. are passed through a second pressure reducing device (7), and the high pressure side on the inlet side and the low pressure side on the outlet side of the second pressure reducing device (7) are made into counter-flow type by a cooling means, that is, a heat exchanger (8). In this example, the high-pressure side is the piping connected to the heat exchange connection and is connected to the gas phase of the condenser (2), and the low-pressure side is the piping from the evaporator (4) exit to the compressor (1). ) is connected to the inlet to form a bypass circuit. 7? −
, the second suppression device (7) is composed of, for example, a capillary. The heat exchanger (8) is a double pipe.

The current structure is such that the high-pressure side of the refrigerant flows through the pipe, and the low-pressure side of the refrigerant flows through the pipe. (9) branches from the high-pressure side of the pipe (6) and flows between the middle part of the heat exchanger (8) and the inlet of the second pressure reducing device (7). In other words, it is a bypass pipe that bypasses the 1% pressure side of the heat exchanger (81).αe is the high pressure downstream from the position where the heat medium flows into the bypass pipe (9) up to the inlet of the pressure reducing device (7). The temperature of the side heat medium is detected.In other words, in this example, the temperature of the second heat medium of the bypass circuit (6) is detected.
The first temperature sensor, αD, is installed in the pipe at the inlet of the pressure reducing device (7) and detects the temperature of the high-pressure refrigerant in the pipe.
df, 2g A second temperature sensor is provided in the piping from the outlet of the pressure device (7) to the low-pressure side inlet of the heat exchanger (8) and detects the temperature of the low-pressure refrigerant in the piping.

02 is a temperature detector to which first and second temperature sensors αα and αD are connected.

FIG. 2 shows the state of the main parts of the cold coop during operation of the heat pump device on a Mollier diagram, and the 'fc' shows the pressure versus ν enthalpy. In the figure, Pd1j is the compression ladder (1) discharge pressure, and Ps is the suction pressure.

A is the compressor fil outlet, and B is the high pressure side outlet of the heat exchanger (8).

B' is the inlet of the capillary (7), C is the capillary (7)
7) Outlet, and D indicate the refrigerant-like precharge at the inlet of the compressor (1), respectively.

Fig. 3 shows an example of a temperature detector, which is composed of a microcomputer M8748 manufactured by Mitsubishi Electric and its peripheral circuits, and temperature sensors ac and H are connected to an A/D converter f.
It is connected to microcomputer I via i3.

Next, the operation will be explained. A part of the high-temperature, high-pressure refrigerant gas discharged by the compressor (1) is divided into the heat exchanger (8) and the bypass pipe (9) from the high-pressure side of the bypass circuit (6), flows into the heat exchanger (8), and then joins again. and flows into the second pressure reducing device (7). Here, one cold # cooled through the heat exchanger (8):
t'i, the liquid state changes from state A to state B shown in Fig. 2 and is slightly supercooled (l), and the other bypass pipe (
The refrigerant that passed through 9) remains in the refrigerant vapor state shown in A,
The refrigerant passes through the heat exchanger (8) and joins with the refrigerant that has become a liquid state, and the refrigerant becomes a two-phase state of gas and liquid as shown in B'. Next, the capillary (7) reduces the pressure to the suction pressure of the compressor (1), changes the state from B' to C, becomes a low-temperature two-phase state, flows through the tubes of the heat exchanger (8), exchanges heat, and is compressed. It flows into the machine (1). At this time, the refrigerant has become a vapor as shown in D. The first temperature sensor (1 (1) is a high-pressure two-phase refrigerant installed at the inlet pipe of the second pressure reducing device (7), and the second temperature sensor (1) installed at the outlet pipe) is a low-pressure The total saturation temperature at that point is detected from the refrigerant in a two-phase state.This consists of a temperature sensor A2 circuit as shown in Figure 3, and the first and second temperature sensors The accompanying resistance change is read as a voltage change and the temperature is detected. Furthermore, the pressure is estimated from the relationship between this saturation temperature and pressure, and the operation of the heat pump device is controlled using the temperature as a control signal.

This invention has the advantage of not requiring an expensive pressure sensor because it detects the saturation temperature, which has a certain relationship with pressure, as a means of determining pressure, and can simultaneously detect pressures on the high and low pressure sides. Furthermore, it is necessary to install a bypass circuit (in the case where there is no bypass pipe (9) on the depressed pressure side of 61, a temperature sensor α! in the middle of the heat exchanger where the high pressure side refrigerant is in a two-phase state!) and the operating conditions However, since the temperature sensor's position changes depending on the temperature, it is difficult to select the location to install the temperature sensor, and it is also difficult to accurately detect the pressure.

By providing the bypass pipe (9), the refrigerant that has been cooled into liquid by the heat exchanger (8) and the refrigerant vapor that has passed through the bypass pipe (9) are mixed, so that the second pressure reducing device (
7) Since it is in a two-phase state at the inlet, it has the effect of being able to accurately detect pressure over a wide operating range.

Further, the second pressure reducing device (7) is not limited to a capillary, but may be an oriice or a nozzle. Furthermore, in the above embodiment, the refrigerant is always allowed to flow through the bypass circuit (61), but an on-off valve may be provided in the middle to allow the refrigerant to flow only when it is desired to detect the pressure. (
Although 8) is a double pipe, the high pressure 61) 1 and low pressure side piping may be brought into contact with each other.

〔Effect of the invention〕

As described above, according to the present invention, in a device in which a compressor, a condenser, a first pressure reducing device, and an evaporator are connected in this order to circulate a heat medium, from the outlet of the compressor to the inlet of the first pressure reducing device. piping that connects the high pressure side of the piping and the low pressure side from the outlet of the first coercive pressure device to the inlet of the compressor via a second pressure reducing device, and cooling that cools the heat medium flowing from the high pressure side of this piping to the Ryou 2 pressure reducing device. means, a bypass means that branches from the high pressure side of the piping and flows from the middle part of the cooling means to the inlet of the second pressure reducing device; a second pressure reducing device downstream from the position where the heat medium of the bypass means flows; The first temperature sensor detects the temperature of the high-pressure heat medium up to the inlet, and the second temperature sensor detects the temperature of the low-pressure heat medium at the outlet of the 19EE device, and the first and second temperature sensors Now that we know the high-pressure side pressure and low-pressure side pressure of the eight pressure devices above, we can estimate the pressure from the saturation temperature since the heat medium is in a two-phase state at the inlet and outlet of the pressure device. This has the effect that a heat pump device that can detect continuous pressure changes with high accuracy can be obtained at low cost.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a heat pump device according to an embodiment of the present invention, and FIG. 2 is a Mollier diagram showing the pressure with respect to the enthalpy of the heat medium at each part during operation of the device shown in FIG. 1. 3 is a circuit diagram showing an embodiment of a temperature detector, and FIG. 4 is a configuration diagram showing a conventional heat pump device. In the figure, (Ild compressor, (21 is a condenser, (3)
is the first pressure reducing device, C4) is the evaporator, (5) is the temperature sensing cylinder of the first pressure reducing device (3), (6a), (6b') is the pressure switch, (6) is the bypass circuit, (7) i! 2nd it
Pressure felt? , (81H heat exchange fi, +91t-! Bypass tube book Q (1-(lυ is the first and second temperature sensor, (I7J is the temperature detector. The same reference numerals in Figure 9 indicate the same - or corresponding parts. shows.

Claims (3)

[Claims] (1) A compressor, a condenser, a first pressure reducing device, and an evaporator are connected in this order to circulate a heat medium,
Piping that connects the high pressure side from the compressor outlet to the first pressure reducing device inlet and the low pressure side from the first pressure reducing device outlet to the compressor inlet via a second pressure reducing device; cooling means for cooling the heat medium flowing into the pressure reducing device;
a bypass means that branches from the high pressure side of the piping and flows from the middle part of the cooling means to the inlet of the second pressure reducing device;
A first temperature sensor detects the temperature of the high-pressure heat medium downstream from the point where the heat medium flows into the bypass means up to the inlet of the second pressure reducing device, and a first temperature sensor that detects the temperature of the high pressure heat medium at the outlet of the second pressure reducing device. Equipped with a second temperature sensor that detects temperature,
A heat pump device characterized in that the high-pressure side pressure and the low-pressure side pressure of the compressor are determined by first and second temperature sensors, respectively. (2) The heat pump device according to claim 1, wherein the high-pressure side of the piping is connected between the outlet of the compressor and the gas phase portion of the condenser. (3) The cooling of the heat medium on the high-pressure side of the piping is performed by cold air on the low-pressure side.
The heat pump device described in Section 1.