JP2012032123A - Flow rate estimating apparatus, heat source machine and flow rate estimating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate estimating apparatus capable of easily estimating a flow rate of a heating medium without using a sensor for detecting the flow rate of the heating medium, and to provide a heat source machine and a flow rate estimating method.SOLUTION: A cold-water inlet temperature sensor Tdetects an inlet temperature of cold water flowing into an evaporator and a cold water outlet temperature sensor Tdetects an outlet temperature of cold water flowing out of the evaporator. Furthermore, the temperature of a refrigerant is detected based on the pressure of the refrigerant in the evaporator which is detected by an evaporation pressure sensor PE. Then, a cold-water flow rate estimation part 50 estimates a flow rate of cold water by a physical model expressing the heat balance of cold water flowing into/out of the evaporator. The physical model is expressed by using the detected cold-water inlet temperature, the detected cold-water outlet temperature, the detected refrigerant temperature, and a value concerned with heat transfer from the evaporator to cold water. Furthermore, a design value of the evaporator is used as a value concerned with heat transfer from the evaporator to cold water.

Description

  The present invention relates to a flow rate estimation device, a heat source device, and a flow rate estimation method.

Conventionally, a turbo chiller, which is an example of a heat source device, performs a high-efficiency operation over a wide load body in accordance with the cooling water inlet temperature and the refrigeration capacity (refrigeration load). Control is performed to switch the machine inlet vane and hot gas bypass valve.
In order to perform the above control, a value indicating the refrigerating capacity is required together with the cooling water inlet temperature. As the cooling number inlet temperature, a value detected by a temperature sensor (cooling water inlet temperature sensor) is used. On the other hand, the refrigeration capacity Q can be calculated by the following formula using the cold water inlet temperature T _CWi and the cold water outlet temperature T _CWo , the cold water flow rate G _CW , and the specific heat Cp _CW of the cold water detected by the temperature sensor. .
Q = G _CW・ Cp _CW・ (T _CWi ‐T _CWo )

  In addition, as a technique for obtaining an appropriate refrigeration capacity range, Patent Document 1 describes the relationship between the head and the refrigeration capacity using a flow coefficient, a pressure coefficient, and a predetermined coefficient at a specific operating point of the turbo compressor. Obtain the arithmetic expression shown, determine the coefficient used in the arithmetic expression using the refrigerating capacity that can take the substantially maximum coefficient of performance in the same head (for example, the same cold water temperature and the same cooling water temperature), The determined coefficient is an optimum coefficient, a predetermined range including the optimum coefficient is an appropriate operation coefficient range, and a technique for obtaining an appropriate refrigeration capacity range from the above arithmetic expression using the appropriate operation coefficient range and a head during operation is provided. Are listed.

JP 2009-204262 A

  Here, since the flow rate sensor is more expensive than the temperature sensor, it may not be provided to the turbo refrigerator. In such a case, for example, a fixed value such as a design value at the rated load is used as the flow rate of the cold water for calculating the refrigerating capacity. However, for example, when the cooling water flow rate decreases and the cooling load decreases, the turbo chiller control is switched from the turbo compressor rotation speed control to the combination of the compressor inlet vane control and the rotation speed control. The turbo refrigerator is controlled so as to reduce the refrigerating capacity. In such a case, if the flow rate of the chilled water is a fixed value, the cooling load is not correctly evaluated. As a result, the correct refrigeration capacity is not calculated and the turbo chiller cannot be operated with high efficiency. .

  The present invention has been made in view of such circumstances, and without using a sensor that detects the flow rate of the heat medium, the flow rate estimation device, the heat source device, and the flow rate estimation that can easily estimate the flow rate of the heat medium. It aims to provide a method.

In order to solve the above problems, the flow rate estimation device, the heat source unit, and the flow rate estimation method of the present invention employ the following means.
That is, the flow rate estimation apparatus according to the present invention provides a flow rate of the heat medium in a heat source device having a compressor that compresses the refrigerant, and a heat exchanger that exchanges heat between the refrigerant compressed by the compressor and the heat medium. A flow rate estimating device for estimating, a first temperature detecting means for detecting an inlet temperature of the heat medium flowing into the heat exchanger, and a second for detecting an outlet temperature of the heat medium flowing out of the heat exchanger. Temperature detection means; third temperature detection means for detecting the temperature of the refrigerant in the heat exchanger; the inlet temperature detected by the first temperature detection means; and the temperature detected by the second temperature detection means. Heat balance of the heat medium flowing into and out of the heat exchanger using the outlet temperature, the temperature of the refrigerant detected by the third temperature detecting means, and the value related to heat transfer from the heat exchanger to the heat medium By a physical model that represents , And a estimating means for estimating the flow rate of the heating medium.

According to the present invention, the first temperature detecting means detects the inlet temperature of the heat medium flowing into the heat exchanger, the second temperature detecting means detects the outlet temperature of the heat medium flowing out of the heat exchanger, The temperature of the refrigerant in the heat exchanger is detected by the third temperature detection means. For example, a thermocouple is used as the first temperature detection unit, the second temperature detection unit, and the third temperature detection unit.
Then, the flow rate of the heat medium is estimated by the estimation unit by a physical model representing the heat balance of the heat medium flowing into and out of the heat exchanger. The physical model includes an inlet temperature detected by the first temperature detecting means, an outlet temperature detected by the second temperature detecting means, a temperature of the refrigerant detected by the third temperature detecting means, and a heat exchanger to the heat medium. It is expressed using the value related to heat transfer. In addition, as a value regarding the heat transfer from the heat exchanger to the heat medium, a design value of the heat exchanger is used.

Further, as the heat medium, either cold water or hot water may be used. When the above physical model is used with the heat medium as cold water, the heat source unit is operated in a freezing operation, and the heat exchanger is an evaporator. On the other hand, when using the said physical model by making a heat medium into warm water, it is a case where a heat source machine is heat-pump-operated, and a heat exchanger becomes a condenser.
From the above, the present invention can easily estimate the flow rate of the heat medium without using a sensor that detects the flow rate of the heat medium.

The flow rate estimation apparatus according to the present invention includes a response delay in the detection of the inlet temperature by the first temperature detection means, a response delay in the detection of the outlet temperature by the second temperature detection means, and the third temperature detection means. Correction means for correcting at least one of the response delays in the detection of the temperature of the refrigerant.
According to the present invention, the flow rate of the heat medium can be estimated more accurately because the flow rate of the heat medium can be estimated using the detected value whose response delay is corrected in the physical model.

In the flow rate estimation device according to the present invention, the value related to heat transfer includes a heat transfer coefficient of the heat exchanger, and the heat transfer coefficient is expressed as a function of the flow rate of the heat medium and the flow rate of the refrigerant. Also good.
According to the present invention, by expressing the heat transfer coefficient of the heat exchanger as a function of the flow rate of the heat medium and the flow rate of the refrigerant among the values related to heat transfer from the heat exchanger to the heat transfer medium, a more accurate heat transfer coefficient Is used in the physical model, the flow rate of the heat medium can be estimated more accurately.

In the flow rate estimation apparatus according to the present invention, the third temperature detection unit may detect the temperature of the refrigerant based on the pressure of the refrigerant in the heat exchanger.
According to the present invention, since the temperature of the refrigerant is detected by the third temperature detection means based on the pressure of the refrigerant in the heat exchanger, the third temperature detection means does not include a dedicated detection means for detecting the temperature of the refrigerant. By detecting the pressure of the refrigerant, the temperature of the refrigerant can be obtained.

On the other hand, a heat source apparatus according to the present invention includes a compressor that compresses a refrigerant, a heat exchanger that exchanges heat between the refrigerant compressed by the compressor and a heat medium, and the flow rate estimation device described above. .
According to the present invention, the heat source device having the compressor that compresses the refrigerant and the heat exchanger that exchanges heat between the refrigerant compressed by the compressor and the heat medium includes the flow rate estimation device described above. The flow rate of the heat medium can be easily estimated without using a sensor that detects the flow rate of the heat medium.

Further, the flow rate estimation method according to the present invention includes a flow rate of the heat medium in a heat source device including a compressor that compresses the refrigerant, and a heat exchanger that exchanges heat between the refrigerant compressed by the compressor and the heat medium. A flow rate estimation method for estimating a temperature of an inlet of the heat medium flowing into the heat exchanger, an outlet temperature of the heat medium flowing out of the heat exchanger, and a temperature of the refrigerant in the heat exchanger. To the heat exchanger using the first step, and the inlet temperature detected by the first step, the outlet temperature, the temperature of the refrigerant, and values related to heat transfer from the heat exchanger to the heat medium. And a second step of estimating a flow rate of the heat medium by a physical model representing a heat balance of the heat medium flowing in and out.
According to the present invention, the inlet temperature of the heat medium flowing into the heat exchanger, the outlet temperature of the heat medium flowing out of the heat exchanger, and the temperature of the refrigerant in the heat exchanger are detected, and the detected inlet temperature and outlet temperature are detected. The flow rate of the heat medium is estimated by a physical model that represents the heat balance of the heat medium flowing into and out of the heat exchanger using values related to the temperature of the refrigerant and heat transfer from the heat exchanger to the heat medium. The flow rate of the heat medium can be easily estimated without using a sensor that detects the flow rate of the medium.

  The present invention has an excellent effect that the flow rate of the heat medium can be easily estimated without using a sensor that detects the flow rate of the heat medium.

It is a block diagram of the turbo refrigerator based on 1st Embodiment of this invention. It is a figure which shows the relationship between the operating end which concerns on 1st Embodiment of this invention, cooling water inlet temperature, and refrigerating capacity. It is a functional block diagram regarding the switching control of the control part which concerns on 1st Embodiment of this invention. It is a schematic diagram required for description of the physical model which concerns on 1st Embodiment of this invention. It is a functional block diagram regarding the switching control of the control part which concerns on 2nd Embodiment of this invention. It is a functional block diagram regarding the switching control of the control part which concerns on other embodiment of this invention.

  Hereinafter, an embodiment of a flow rate estimation device, a heat source device, and a flow rate estimation method according to the present invention will be described with reference to the drawings.

[First Embodiment]
The first embodiment of the present invention will be described below.
In FIG. 1, the structure of the turbo refrigerator 10 which is an example of the heat source machine which concerns on this 1st Embodiment is shown.
The turbo refrigerator 10 includes a turbo compressor 12 that compresses the refrigerant, a condenser 14 that condenses the high-temperature and high-pressure gas refrigerant compressed by the turbo compressor 12, and the liquid refrigerant that is condensed in the condenser 14. The subcooler 16 that provides supercooling, the high-pressure expansion valve 18 that expands the liquid refrigerant from the subcooler 16, and the intermediate cooling that is connected to the high-pressure expansion valve 18 and to the intermediate stage of the turbo compressor 12 and the low-pressure expansion valve 20 And an evaporator 24 for evaporating the liquid refrigerant expanded by the low-pressure expansion valve 20.

  The turbo compressor 12 is a centrifugal two-stage compressor, and is driven by an electric motor 28 whose rotational speed is controlled by an inverter 26. The output of the inverter 26 is controlled by the control unit 30. The refrigerant inlet of the turbo compressor 12 is provided with a compressor inlet vane (IGV) 32 for controlling the intake refrigerant flow rate, and the capacity control of the turbo refrigerator 10 is possible.

The condenser 14 as a heat exchanger is provided with a condensed refrigerant pressure sensor PC for detecting the condensed refrigerant pressure. The output of the sensor PC is transmitted to the control unit 30.
The subcooler 16 is provided on the downstream side of the refrigerant flow of the condenser 14 so as to supercool the condensed refrigerant. Immediately after the refrigerant flow downstream side of the subcooler 16, a temperature sensor T _s for detecting the refrigerant temperature after supercooling is provided.
The condenser 14 and the subcooler 16 are inserted with cooling heat transfer tubes 34 for cooling them. The cooling water outlet temperature is detected by a cooling water outlet temperature sensor T _cout , and the cooling water inlet temperature is detected by a cooling water inlet temperature sensor T _cin . Note that the cooling water is exhausted to the outside in a cooling tower (not shown), and then led to the condenser 14 and the subcooler 16 again.

The intermediate cooler 22 is provided with an intermediate pressure sensor PM for detecting an intermediate pressure.
The evaporator 24, which is a heat exchanger, is provided with an evaporation pressure sensor PE for detecting the evaporation pressure. A refrigerant having a rated temperature (for example, 7 ° C.) is obtained by absorbing heat in the evaporator 24. A cold water heat transfer tube 36 for cooling a heat medium (hereinafter referred to as “cold water”) supplied to an external load is inserted into the evaporator 24. The temperature of cold water flowing out from the evaporator 24 in the cold water heat transfer pipe 36 (hereinafter referred to as “cold water outlet temperature”) is detected by the cold water outlet temperature sensor T _out and flows into the evaporator 24 in the cold water heat transfer pipe 36. the cold water temperature (hereinafter referred to as "cold water inlet temperature.") is detected by the cold water inlet temperature sensor T _in.
A hot gas bypass pipe 38 is provided between the gas phase part of the condenser 14 and the gas phase part of the evaporator 24. The hot gas bypass pipe 38 is provided with a hot gas bypass valve 40 for controlling the flow rate of the refrigerant flowing in the hot gas bypass pipe 38. By adjusting the hot gas bypass flow rate by the hot gas bypass valve 40, the compressor inlet vane 32 can control the capacity of a very small region that is not sufficiently controlled.
In addition, although the turbo refrigerator 10 which concerns on this embodiment uses a thermocouple as each temperature sensor, for example, you may use not only this but other sensors, such as a resistance temperature sensor, as a temperature sensor.

Here, the turbo chiller 10 according to the first embodiment has an operation end (the turbo compressor 12 according to the cooling water inlet temperature and the refrigeration capacity Q as shown in FIG. Switching control for switching the rotational speed of the compressor, the compressor inlet vane 32, and the hot gas bypass valve 40).
The refrigeration capacity Q used to perform this switching control is, for example, using the cold water inlet temperature T _CWi , the cold water outlet temperature T _CWo , the cold water flow rate G _CW , and the specific heat Cp _CW of cold water, Q = G _CW Calculated by _CW · (T _CWi -T _CWo ).

FIG. 3 is a functional block diagram of the control unit 30 for performing switching control.
The control unit 30 includes a cold water flow rate estimation unit 50 and an operation command value deriving unit 52.

The chilled water flow rate estimation unit 50 flows into and out of the evaporator 24 using values regarding the chilled water inlet temperature T _CWi , the chilled water outlet temperature T _CWo , the refrigerant temperature in the evaporator 24, and the heat transfer from the evaporator 24 to the chilled water. The chilled water flow rate is estimated by a physical model representing the heat balance of the chilled water.

Here, in the turbo chiller 10 according to the present embodiment, the cold water flow rate is estimated by calculating from the physical model represented by the following equation (1). Equation (1) expresses the dynamic behavior of the cold water outlet temperature as a discrete equation.
In the equation (1), M _CW is the amount of cold water held in the evaporator 24, Cp _CW is the specific heat of cold water held in the evaporator 24, and _MEM is the heat transfer surface of the evaporator 24 ( The metal part of the evaporator 24, the weight of the cold water heat transfer tube 36), Cp _EM is the specific heat of the heat transfer surface of the evaporator 24, U _E is the heat transfer coefficient of the evaporator 24, and A _E is the heat transfer area of the evaporator 24 , T _E is the refrigerant temperature in the evaporator 24. Δt represents a sampling time, and i represents each time step.

In the present embodiment, the temperature detected by the cold water inlet temperature sensor T _in the cold water inlet temperature T _CWi, the temperature detected by the cold water outlet temperature sensor T _out the coolant outlet temperature T _CWO, is detected by the evaporation pressure sensor PE and the saturation temperature of the refrigerant obtained from the pressure has a refrigerant temperature T _E in the evaporator 24.
On the other hand, the cold water quantity M _CW that are held in the evaporator 24, cold water specific heat Cp _CW, the weight M _EM heat transfer surface of the evaporator 24, the specific heat Cp _EM of the heat transfer surface, the heat transfer coefficient of the evaporator 24 U _E , the heat transfer area A _{E of} the evaporator, and the refrigerant temperature T _E in the evaporator 24 are values obtained from design values, and each design value is stored in a magnetic memory device or a semiconductor memory device (not shown). The cold water flow rate estimation unit 50 reads each design value from the storage means when estimating the cold water flow rate.

Here, the left side of the equation (1) is a term of time differentiation, which is the product of the sum of the heat capacity of the cold water held by the evaporator 24 and the heat capacity of the evaporator 24 and the amount of change in the temperature of the cold water outlet with time. is there. The first term on the right side of equation (1) indicates the product of the cold water flow rate, the specific heat of the cold water, and the temperature difference between the inlet and outlet of the cold water with respect to the evaporator 24, and the second term on the right side of equation (1) is the evaporator. The amount of heat transferred by heat transfer from the refrigerant in 24 to the cold water is shown. That is, the equation (1) is a physical model showing a balance between the heat capacity of the cold water and the heat capacity of the metal part of the evaporator 24.
In practice, the evaporator 24 transfers heat from the cold water to the heat transfer surface of the evaporator 24 and from the heat transfer surface of the evaporator 24 to the refrigerant. Equation (1) is a schematic diagram of FIG. As shown in FIG. 4, the simplified physical model assumes that the heat transfer surface temperature T _M of the evaporator 24 is equal to the cold water outlet temperature T _CWo .

Then, equation (2) for calculating the cold water flow rate G _CW is derived from equation (1).

The operation command value deriving unit 52 calculates the refrigerating capacity Q using the cold water flow rate estimated by the cold water flow rate estimating unit 50.
Further, the operation command value deriving unit 52 determines the rotation speed command value indicating the rotation speed of the turbo compressor 12 according to the calculated refrigeration capacity Q and the cooling water inlet temperature detected by the cooling water inlet temperature sensor T _cin. Is transmitted to the turbo compressor 12 and a vane opening command value indicating the opening of the compressor inlet vane 32 is derived and transmitted to the compressor inlet vane 32 to indicate the opening of the hot gas bypass valve 40. A bypass valve opening command value is derived and transmitted to the hot gas bypass valve.
When the turbo compressor 12 receives the rotational speed command value, the turbo compressor 12 rotates at the rotational speed indicated by the rotational speed command value, and when receiving the vane opening command value, the compressor inlet vane 32 opens. When the hot gas bypass valve 40 receives the bypass valve opening command value, the hot gas bypass valve 40 opens at the opening indicated by the bypass valve opening command value.

As described above, the turbo refrigerator 10 according to the first embodiment, the cold water inlet temperature sensor T _in detects the cold water inlet temperature that flows into the evaporator 24, the cold water outlet temperature sensor T _out is evaporated The outlet temperature of the cold water flowing out from the vessel 24 is detected. Further, the temperature of the refrigerant is detected based on the pressure of the refrigerant in the evaporator 24 detected by the evaporation pressure sensor PE. Then, the cold water flow rate estimation unit 50 estimates the flow rate of the cold water using a physical model representing the heat balance of the cold water flowing into and out of the evaporator 24. This physical model is represented by using the detected cold water inlet temperature, the detected cold water outlet temperature, the detected refrigerant temperature, and the values relating to the heat transfer from the evaporator 24 to the cold water.
From the above, the turbo chiller 10 according to the first embodiment can easily estimate the flow rate of cold water without using a sensor that detects the flow rate of cold water flowing into and out of the evaporator 24.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described.

The configuration of the turbo refrigerator 10 according to the second embodiment is the same as the configuration of the turbo refrigerator 10 according to the first embodiment shown in FIG.
FIG. 5 shows a functional block configuration of the control unit 30 according to the second embodiment. 5 that are the same as those in FIG. 3 are assigned the same reference numerals as in FIG. 3 and descriptions thereof are omitted.
The control unit 30 according to the second embodiment includes sensor compensators 60A to 60D. Since various sensors have response delays, there is a difference between the value detected by each sensor and the actual value (hereinafter referred to as “true value”). Therefore, the sensor compensators 60A to 60D correct response delays of the corresponding sensors. In the following description, when each sensor compensator 60 is distinguished, any of A to D is added to the end of the reference numeral, and when each sensor compensator 60 is not distinguished, A to D are omitted.

Sensor compensator 60A corrects the delay of the detection of the cold water inlet temperature by the cold water inlet temperature sensor T _in.
The sensor compensator 60B corrects a delay in detecting the cold water outlet temperature by the cold water outlet temperature sensor _Tout .
The sensor compensator 60C corrects the delay in detecting the evaporation pressure by the evaporation pressure sensor PE. Note that a pressure sensor (for example, a strain gauge type pressure sensor) has a response delay smaller than that of the temperature sensor, and therefore may not be provided with the sensor compensator 60C in the control unit 30.
The sensor compensator 60D corrects a delay in detection of the cooling water inlet temperature by the cooling water inlet temperature sensor T _cin .

そして、（３）式から（４）式が導かれる。

Then, the sensor compensator 60 corrects the detection value T by each sensor to the true value T ′ using the following equations (3) and (4). In the equation (3), τ is a time constant of each sensor, and is stored in advance in storage means (not shown).

Then, equation (4) is derived from equation (3).

以上説明したように、本第２実施形態に係るターボ冷凍機１０は、センサー補償器６０によって、冷水入口温度センサーＴ_ｉｎによる冷水入口温度の検出の応答遅れ、冷水出口温度センサーＴ_ｏｕｔによる冷水出口温度の検出の応答遅れ、及び蒸発圧力センサーＰＥによる蒸発圧力の検出の遅れが補正されるので、蒸発器２４に流入出する冷水の流量を検出するセンサーを用いることなく、より正確に冷水の流量を推定できる。 Furthermore, by using the true value T ′ obtained by the correction by the sensor compensator 60, the cold water flow rate G _CW is calculated by the following equation (5).

As described above, the turbo refrigerator 10 according to the second embodiment, the sensor compensator 60, the cold water inlet temperature sensor T _in the cold water inlet temperature response of the detection delay of by cold water outlet by chilled water outlet temperature sensor T _out Since the response delay in detecting the temperature and the delay in detecting the evaporating pressure by the evaporating pressure sensor PE are corrected, the flow rate of the chilled water can be accurately measured without using a sensor for detecting the flow rate of the chilled water flowing into and out of the evaporator 24. Can be estimated.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described.

The configuration of the turbo chiller 10 according to the third embodiment and the configuration of the functional block of the control unit 30 are shown in the configuration of the turbo chiller 10 according to the first embodiment shown in FIG. 1 and FIG. Since it is the same as the structure of the functional block of the control part 30 which concerns on 2nd Embodiment, description is abbreviate | omitted.
In the first and second embodiments described above, the case where the design value, that is, the fixed value is used as the heat transfer coefficient U _E of the evaporator 24 has been described. However, the value of the heat transfer coefficient changes according to the flow conditions of the two fluids (cold water and refrigerant in the third embodiment) via the heat transfer surface. Therefore, the heat transfer coefficient can be expressed as the following equation (6) as a two-variable function of the cold water flow rate G _CW and the refrigerant flow rate G _E. Therefore, in the cold water flow rate estimating unit 50 according to the third embodiment, the heat transfer coefficient U _E is set as a heat transfer coefficient U ′ _E expressed as a two-variable function.

The cold water flow rate estimation unit 50 according to the third embodiment uses the refrigerant flow rate G _E , the characteristic map of the turbo compressor 12, the differential pressure between the evaporator 24 and the condenser 14, and the turbo compressor 12 and the compressor inlet vane. It is calculated from the opening of 32.
The chilled water flow rate estimation unit 50 according to the third embodiment is a nonlinear equation in which the heat transfer coefficient U _E in the equation (5) is replaced with the heat transfer coefficient U ′ _E represented by the equation (6) ( 7) Calculate the cold water flow rate G _CW from the equation.

  As described above, the turbo chiller 10 according to the third embodiment uses the heat transfer coefficient of the evaporator 24 among the values related to the heat transfer from the evaporator 24 to the cold water as a function of the flow rate of the cold water and the flow rate of the refrigerant. Represent as Thereby, although convergence calculation for solving the nonlinear equation represented by the equation (7) is required, the flow rate of the chilled water can be more accurately detected without using a sensor for detecting the flow rate of the chilled water flowing into and out of the evaporator 24. Can be estimated.

Incidentally, the cold water flow rate estimation unit 50 according to the third embodiment has described the case of replacing the heat transfer coefficient U _'E represented the heat transfer coefficient U _E (6) In equation in (5), the The invention is not limited to this, and the cold water flow rate G _CW is calculated from a non-linear equation in which the heat transfer coefficient U _E in equation (2) is replaced with the heat transfer coefficient U ′ _E expressed in equation (6). It is good also as a form.

  As mentioned above, although this invention was demonstrated using said each embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above-described embodiments without departing from the gist of the invention, and embodiments to which the changes or improvements are added are also included in the technical scope of the present invention.

For example, the above embodiments have described the case of deriving from the refrigerant temperature T _E of the evaporation pressure sensor PE in detected pressure in the evaporator 24, the present invention is not limited to this, FIG. the coolant temperature sensor 80 for detecting the temperature of the refrigerant in the evaporator 24 as shown in 6 is provided, the detected values by the refrigerant temperature sensor 80 may be configured to a refrigerant temperature T _E.

In each of the above embodiments, it is assumed that the heat transfer surface temperature T _M of the evaporator 24 is equal to the chilled water outlet temperature T _CWo , that is, the case where the chilled water flow rate G _CW is calculated from a simplified physical model. However, the present invention is not limited to this. Heat transfer from the cold water to the heat transfer surface of the evaporator 24 and heat transfer from the heat transfer surface of the evaporator 24 to the refrigerant in the evaporator 24 are performed. The cold water flow rate G _CW may be calculated from the physical model considered. According to this embodiment, a more accurate cold water flow rate can be estimated.

Calculation formulas in the case of this embodiment are shown in the following formulas (8) and (9). Expression (8) is an expression representing heat transfer from the heat transfer surface of the evaporator 24 to the refrigerant in the evaporator. On the other hand, (9) is an expression that represents the heat transfer to the heat transfer surface of the evaporator 24 from cold water, substitutes the heat transfer surface temperature T _M calculated from equation (8) to (9) Thus, the cold water flow rate G _CW is calculated.
In Eqs. (8) and (9), U _E ^CW-M is the heat transfer coefficient between the cold water and the heat transfer surface, and A _E ^CW-M is the heat transfer between the cold water and the heat transfer surface. U _E ^EM is a heat transfer coefficient between the refrigerant and the heat transfer surface, and A _E ^EM is a heat transfer area between the refrigerant and the heat transfer surface.

In each of the above embodiments, the case where the present invention is applied to the centrifugal chiller 10 that performs the refrigeration operation has been described. However, the present invention is not limited to this, and the present invention is applied to a heat pump turbo chiller that can also perform the heat pump operation. Also good.
In this case, the evaporator 24 is used as a condenser, and the heat medium whose flow rate is estimated is warm water.

10 turbo refrigerator 12 turbo compressor 24 evaporator 50 the cold water flow rate estimation unit 60 sensor compensator T _OUT coolant outlet temperature sensor T _in the cold water inlet temperature sensor PE evaporation pressure sensor

Claims (6)

A flow rate estimation device for estimating a flow rate of the heat medium in a heat source machine having a compressor that compresses the refrigerant, and a heat exchanger that exchanges heat between the refrigerant compressed by the compressor and the heat medium,
First temperature detecting means for detecting an inlet temperature of the heat medium flowing into the heat exchanger;
Second temperature detecting means for detecting an outlet temperature of the heat medium flowing out from the heat exchanger;
Third temperature detecting means for detecting the temperature of the refrigerant in the heat exchanger;
From the inlet temperature detected by the first temperature detecting means, the outlet temperature detected by the second temperature detecting means, the temperature of the refrigerant detected by the third temperature detecting means, and the heat exchanger Estimating means for estimating the flow rate of the heat medium by a physical model representing the heat balance of the heat medium flowing into and out of the heat exchanger using values relating to heat transfer to the heat medium;
A flow rate estimation apparatus comprising:   Response delay in detection of the inlet temperature by the first temperature detection means, response delay in detection of the outlet temperature by the second temperature detection means, and response delay in detection of the refrigerant temperature by the third temperature detection means. The flow rate estimation apparatus according to claim 1, further comprising a correction unit that corrects at least one of them. The heat transfer value includes a heat transfer coefficient of the heat exchanger,
The flow rate estimation device according to claim 1, wherein the heat transfer coefficient is expressed as a function of a flow rate of the heat medium and a flow rate of the refrigerant.   The flow rate estimation apparatus according to any one of claims 1 to 3, wherein the third temperature detection means detects a temperature of the refrigerant based on a pressure of the refrigerant in the heat exchanger. A compressor for compressing the refrigerant;
A heat exchanger that exchanges heat between the refrigerant and the heat medium compressed by the compressor;
A flow rate estimation apparatus according to any one of claims 1 to 4,
Heat source machine equipped with. A flow rate estimation method for estimating a flow rate of the heat medium in a heat source machine having a compressor that compresses the refrigerant, and a heat exchanger that exchanges heat between the refrigerant compressed by the compressor and the heat medium,
A first step of detecting an inlet temperature of the heat medium flowing into the heat exchanger, an outlet temperature of the heat medium flowing out of the heat exchanger, and a temperature of the refrigerant in the heat exchanger;
The heating medium flowing into and out of the heat exchanger using values of the inlet temperature, the outlet temperature, the refrigerant temperature, and the heat transfer from the heat exchanger to the heating medium detected in the first step. A second step of estimating the flow rate of the heat medium by a physical model representing the heat balance of
A flow rate estimation method including:

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