JP2006162380A - Measuring method of input energy of equipment apparatus, and measuring method of steam flow rate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To readily measure the energy input quantity of facility apparatus that uses steam as energy source, without cutting pipes. <P>SOLUTION: The temperature of steam flowing into an absorption refrigerating machine 1 is measured, and inlet side steam enthalpy is determined. The temperature of steam condensate outputted from the absorption refrigerating machine 1 is measured, and output side steam enthalpy is determined. An ultrasonic flowmeter 19 for liquid use is mounted on the surface of a vertical tube 15 in which the steam condensate flows, and the flow rate of the steam condensate is determined. Resultantly, steam energy inputted into the absorption refrigerating machine 1 can be determined, by subtracting the output side steam enthalpy from the inlet side steam enthalpy, and multiplying the result by the flow rate of the steam condensate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for measuring input energy (consumed energy) and a method for measuring a steam flow rate of equipment such as an absorption chiller, a steam-driven turbine, a heating facility, and the like that are supplied with steam energy.

  About half of the energy consumed by buildings (mainly building buildings) is consumed by air-conditioning energy, and 60% of that energy is consumed by heat source equipment such as refrigerators. In particular, a decrease in the performance of a refrigerator will immediately lead to an increase in energy consumption, so it is indispensable to evaluate the performance of the refrigerator in order to save energy in a building.

  Generally, COP (ratio of input energy to production energy) is used as a performance index of the refrigerator, and the degree of deterioration is determined by comparing with factory test results. When the performance of the refrigerator decreases, the amount of input increases with respect to the amount of production heat, so the fuel consumption of electricity, gas, and oil also increases. In an electric turbo chiller, the input is electricity, and the input energy can be specified by installing a power meter or the like.

  However, there are few existing facilities equipped with measuring equipment for the input energy of steam in absorption chillers to which steam is charged. The reason for this is that a steam flow meter that directly measures the flow rate of steam is very expensive and does not directly reflect the running cost like gas or oil (steam is one of the media for energy transfer). There is). In addition, re-installation after a new construction may require a great deal of cost and labor, such as cutting and removing piping. When the performance of an absorption refrigerator decreases, the amount of steam consumed increases with respect to the amount of heat produced, and thus the amount of consumption of gas and oil as fuel increases. Therefore, an inexpensive and simple method for measuring the energy input of a vapor absorption refrigerator is desired.

As described above, in an absorption refrigerator that produces cold using steam as an energy source, grasping the performance of the refrigerator is indispensable for energy saving and high-efficiency operation of the refrigerator.
For evaluation of the performance of the refrigerator, the amount of cold heat produced and the input amount of energy required for it are measured. For example, a COP obtained by dividing the amount of cold heat by the input amount is used. Here, in order to measure the amount of energy input, that is, the amount of heat of the steam consumed by the refrigerator, the flow rate of the steam flowing through the steam inlet pipe of the absorption refrigerator is measured, and the enthalpy of saturated steam entering the absorption refrigerator and the absorption refrigeration Multiply the difference in the enthalpy of steam return water from the machine. Therefore, to obtain the COP of the absorption refrigerator, it is necessary to obtain the steam flow rate and the enthalpy of steam and return water.

  Also, when steam of specified conditions (pressure, temperature) is input to condense the steam to a specific temperature to measure the usage status of equipment with a condenser that uses steam energy, this occurs in boilers When measuring the distribution of steam in equipment that distributes steam to multiple devices (for example, when supplying steam for heating in a district heating system), the steam inlet conditions (temperature, pressure), return water When the outlet conditions (temperature, pressure) can both be defined or deemed to be specified, it is particularly necessary to obtain the steam flow rate.

In this regard, conventional steam flow meters for measuring the steam flow include the following.
(A) A flow meter in which a detection mechanism is inserted into a pipe and brought into direct contact with a fluid. This type includes a turbine type, an orifice type, and a cone type.
(B) Non-contact type flow meter in which the detection mechanism does not come into contact with the fluid. This type includes an ultrasonic method using a special short tube called a so-called semi-clamp on type. This is an ultrasonic wave that is alternately transmitted and received from two ultrasonic transmitters, measures the steam flow velocity from the time difference between the steam flow direction and the forward and reverse directions, and multiplies the tube cross-sectional area to obtain the steam flow rate. Although it is a propagation time difference type, because there is attenuation of ultrasonic waves on the ultrasonic transmitter, pipe surface and pipe material, a special short pipe that integrates the protective pipe and pipe of the ultrasonic transmitter / receiver is inserted in the middle of the pipe. There is a need to.
Patent Document 1 discloses that the flow rate of condensate flowing through the steam pipe is measured.

Japanese Patent Publication No. 6-63793

In the steam flow measurement method using the conventional steam flow meter described above, if there is no individual steam flow meter for each absorption refrigerator, the operation of the absorption refrigerator is stopped, and a part of the steam pipe is cut off. It was necessary to remove this and attach a flow meter. As a result, the measurement takes a considerable amount of time and money, and the operation of the refrigerator is stopped, so that the supply of cold heat must also be stopped. In addition, in the measurement of these vapors, there are many additional measuring instruments that separately measure the vapor pressure or measure the vapor temperature and convert it to the pressure to obtain the vapor mass flow rate from the vapor specific volume due to the pressure. In general, it is necessary to measure the temperature and pressure required to measure the input quantity of the absorption refrigerator with an insertion-type thermometer or insertion-type pressure gauge. From this point, part of the steam pipe is cut and removed.
Therefore, in the past, in order to measure the input energy of an absorption chiller without a steam flow meter, it was inevitable to cut or remove the piping and stop the equipment due to that. Moreover, the thing of patent document 1 does not aim at specification of input steam quantity and input energy, and even if it is used, input steam quantity and input energy cannot be calculated | required immediately.

  This invention is made | formed in view of this point, and it aims at providing the method of measuring easily the energy input amount of the installation equipment which uses steam as an energy source, without cut | disconnecting piping. In addition, a method for measuring the steam flow rate is also provided.

  In order to achieve the above object, the present invention is a method for measuring steam energy input to equipment using steam, and measures the temperature of the steam flowing into the equipment to determine the inlet side steam enthalpy. Measuring the temperature of the steam return water exiting from the equipment and determining the outlet side steam enthalpy, and applying the ultrasonic flowmeter for liquid attached to the surface of the pipe through which the steam return water exiting the equipment flows. And obtaining a flow rate of the steam return water. Then, the outlet side steam enthalpy is subtracted from the inlet side steam enthalpy, and the result is multiplied by the flow rate of the steam return water to obtain the steam energy input to the equipment.

  In order to measure the temperature of the steam flowing into the equipment and determine the inlet-side steam enthalpy, the temperature-specific enthalpy relationship of the inlet-side steam enthalpy is determined in advance, and the conversion formula for the inlet-side steam enthalpy is approximated based on this relationship. If the equation is used, the inlet-side steam enthalpy can be obtained immediately from the measured temperature. Similarly, in order to measure the temperature of the steam return water from the equipment and determine the outlet side steam enthalpy, the temperature-specific enthalpy relationship of the outlet side return water enthalpy is obtained in advance, and the outlet side return water is determined based on the relationship. Find the enthalpy conversion formula.

  And the instantaneous value of the volume flow of the steam return water measured by the ultrasonic flowmeter for liquid attached to the surface of the pipe through which the steam return water from the facility equipment flows was time-averaged, and the average value of the return water temperature was obtained. The steam flow rate is obtained by converting the mass flow rate divided by the specific volume of water. Further, by subtracting the outlet-side steam enthalpy from the inlet-side steam enthalpy and multiplying the result by the flow rate of the steam return water, the steam energy input to the equipment can be obtained.

  As the liquid ultrasonic flowmeter, for example, an existing one utilizing a difference in propagation time of ultrasonic waves or the Doppler effect can be used. Although the flow of the return water is intermittent due to the condensation trap, the instantaneous value of the return water flow rate (volume flow rate) measured by the ultrasonic flowmeter for liquid is time-averaged (time integration), and the return water flow The steam flow rate can be obtained in terms of the mass flow rate divided by the specific volume of water obtained by the average temperature value.

If the return water flow rate is not averaged, a stable measured value of the steam input cannot be obtained due to the intermittent flow of the return water due to the intermittent operation of the condensation trap. In equipment that seals from steam to return water, mass conservation between the steam and return water is always true.
Although the return water flow rate measured by the ultrasonic flowmeter is a volume flow rate, conversion to mass flow rate has no practical problem if the relationship between temperature and specific volume is used. For example, 1 liter is simply converted to 1 kg. However, the error is at most 3 to 4%. If there is no condensation trap and the steam is completely consumed up to the return water (heat exchanged and cooled), and there is no fluctuation in the steam flow and no pressure fluctuation in the equipment, the return water flow and the steam flow Instantaneous values are equal. That is, return water flow rate (instantaneous value) = steam flow rate (instantaneous value).
However, if there is a condensation trap, the intermittent return of the condensation trap will be equal even if the flow rate of the return water flowing intermittently and the constant flow rate of steam are compared at an instantaneous value at a certain point in time. Don't be. Therefore, by integrating (averaging) instantaneous data of the return water flow rate for a predetermined time, it becomes equal to (average of) the steam flow rate. That is, it can be paraphrased that the time integration values are equal as follows. Return water flow rate (time integral value) = Steam flow rate (time integral value)
Therefore, as the steam flow rate input to the equipment is constant and stable, the return water flow rate and the steam flow rate agree well even with a short time average. As a result, the return water flow rate and the steam flow rate become equal. Therefore, when obtaining the flow rate of the steam return water, it is preferable to perform an averaging process on the return water flow rate data measured as an instantaneous value and use this as the return water flow rate.

The liquid ultrasonic flowmeter should be installed on the surface of the vertical pipe through which the steam return water flows. This makes it possible to measure the flow rate of the return water (steam flow rate) from the pipe surface because the upstream condensate trap is always in full operation even if it is intermittently operated.

  For example, a temperature logger can be used to measure the temperature of the steam flowing into the equipment, but if a thermocouple is used, this should be measured even if the steam inlet temperature exceeds 300 ° C. It is possible to extend the range of input energy measurement target equipment to, for example, a steam-driven turbine using high-temperature steam.

  ADVANTAGE OF THE INVENTION According to this invention, the energy input amount of the equipment which uses steam as an energy source can be measured simply, without cutting or removing piping.

  Hereinafter, preferred embodiments of the present invention will be described. FIG. 1 shows the circumference of a steam pipe of an absorption refrigerator 1 as an example of equipment to be measured. The absorption refrigerator 1 includes a regenerator 2, a condenser 3, an absorber / evaporator 4. Yes.

  The regenerator 2 includes, for example, a pipe 11 for introducing steam generated by a high-temperature steam generator (not shown) such as a boiler into the absorption refrigerator 1 and the absorption refrigerator 1 using the introduced steam, for example, cooling A pipe 12 for returning the steam after the production to the high-temperature steam generator is connected. The pipe 11 is provided with an automatic valve 13 for controlling the amount of cold heat produced by the absorption refrigerator 1. The pipe 12 is provided with a condensing trap 14 as a condensing device that traps and condenses the vapor after leaving the regenerator 2 of the absorption refrigerator 1. A vertical pipe 15 is piped downstream of the condensation trap 14.

  Between the regenerator 2 and the automatic valve 13 in the pipe 11, a temperature sensor 16 that measures the temperature of the high-temperature steam flowing in the pipe 11 is provided, and the vertical pipe 15 has a return water flowing in the vertical pipe 15. A temperature sensor 17 for measuring the temperature is provided. Detection signals from these temperature sensors 16 and 17 are input to the temperature logger 18. Various temperature sensors 16 and 17 can be used. For example, those disclosed in JP-A-2001-296187 can be used by being attached to the surface of the pipe.

  Between the temperature sensors 16 and 17 and the pipe 11 and the vertical pipe 17, it is preferable to apply heat conductive silicon to the junction between the temperature sensor and the pipe surface to improve heat transfer. . In addition, it is desirable that the piping portion to which the temperature sensors 16 and 17 are attached is appropriately heated to reduce measurement errors. The inlet steam temperature of the absorption refrigerator 1 is approximately 150 to 180 ° C. The temperature of the steam return water in the vertical tube 15 after leaving the regenerator 2 and condensed in the condensation trap 14 is approximately 80 to 100 ° C.

  An ultrasonic flow meter 19 for liquid is provided on the downstream side of the temperature sensor 17 in the vertical tube 15. The ultrasonic flow meter 19 is a so-called clamp-on type in which an ultrasonic transmitter / receiver is installed on the outer wall of a pipe. In this way, the installation position of the ultrasonic flowmeter 19 for liquid is the vertical pipe 15 after the condensation trap 14, so that the steam return water becomes full in the pipe, and the steam flow rate can be measured from the pipe surface. . Moreover, it is desirable that the attachment position of the ultrasonic flowmeter 19 is a position sufficiently away from the absorption refrigerator 1. As a result, the temperature of the surface of the vertical pipe 15 is cooled by the ambient air, so that the heat load of the ultrasonic transmitter / receiver (not shown) of the ultrasonic flowmeter 19 up to about 130 ° C. even if the heat resistant temperature is high. Can be reduced. In addition, even when steam (bubbles) is mixed during the operation of the condensation trap, the piping is cooled and the return water in the piping is cooled, so that a full water state can be ensured.

  The circumference of the piping of the absorption refrigerator 1 and the main equipment for carrying out the measurement method according to the embodiment of the present invention are configured as described above. Next, a specific measurement method will be described.

First, the steam enthalpy is obtained from the temperature of the steam flowing through the pipe 11. Conversion from steam temperature to steam enthalpy can be obtained by the conversion formula shown in FIG. In the present embodiment, a conversion formula created based on a data table described in a known document (for example, the Air Conditioning and Sanitation Engineering Society: Air Conditioning and Sanitation Engineering Handbook 13th Edition, Volume 1, Basic Edition (2001)) is used. It was.
In the present embodiment, the following conversion formula is obtained.
Steam temperature specific enthalpy h '' (kJ / kg)
= −0.00001 × (steam temperature) ³ + 0.0007 × (steam temperature) ²
+ 1.7981 × (steam temperature) +2501.2

Further, the return water enthalpy is obtained from the temperature of the steam return water flowing through the vertical pipe 15. Conversion from steam return water temperature to return water enthalpy can be obtained by the conversion formula shown in FIG. This is a conversion formula created based on a data table described in a known document (for example, the Society for Air Conditioning and Sanitation Engineering: Air Conditioning and Sanitation Engineering Handbook 13th Edition, Volume 1, Basic Edition (2001)).
In the present embodiment, the following conversion formula is obtained.
Specific enthalpy of return water temperature h ′ (kJ / kg) = 4.2208 × return water temperature

  Then, an instantaneous value of the volume flow rate of the steam return water flowing through the vertical pipe 15 is measured by the ultrasonic flow meter 19, converted into a mass flow rate, and averaged to obtain the steam flow rate. Regarding the processing method of the measurement value of the return water flow rate, since the condensation trap 14 operates intermittently, the instantaneous value of the flow rate measured at a sampling period of several seconds to several minutes is once recorded in a data logger (not shown), By averaging the measured values for several tens of minutes to about one hour, it is possible to specify a stable and stable steam input. It is desirable to evaluate the performance of the absorption refrigerator 1 with data obtained by such processing. By performing the above processing, it is possible to measure with an accuracy of several percent compared to a pipe-inserted flow meter, and within 3% when compared with actual measurements. FIG. 4 shows a measurement result (solid line: central data) by a pipe insertion type vortex steam flow meter, a measurement result by this embodiment (circle), and a comparison result.

From the above measurement results, the steam energy amount Q (kW) input to the absorption refrigerator 1 can be calculated by the following equation. That is, Sv: Steam flow rate (kg / s) measured by the vertical pipe 15, Hi: Steam enthalpy (kJ / kg) estimated from the steam temperature measured by the pipe 11 on the steam inlet side of the absorption refrigerator 1, H ₀ : When the enthalpy (kj / kg) estimated from the return water temperature measured by the vertical pipe 15 is used,
Q = Sv × (Hi−H ₀ )
It is.

Therefore, according to the measurement method according to the present embodiment, the operation of the absorption refrigerator 1 that is in operation is stopped without cutting and removing the steam pipes even in a refrigerator that is not provided with an existing steam flow meter. Therefore, the amount of input energy can be specified as direct measurement, and the performance evaluation of the absorption refrigerator 1 can be performed.
Also, by measuring the steam flow rate and enthalpy of the absorption refrigerator 1 in operation, the amount of input energy can be measured, so that the time and cost required for measurement, such as pipe cutting and installation of a steam flow meter, can be saved. In addition, since there is no stop of the cold supply due to the stop of the absorption refrigerator 1 accompanying the construction, it is not necessary to stop the operation of other equipment. In this way, there is no need to stop the various equipment, so there is no excessive burden on equipment management.
Even if there is an existing measuring device, it can be installed in parallel with the existing measuring device and can be used to check the operation of the existing measuring device without obstructing the conventional monitoring device and equipment.

  As for the temperature sensor 16 for measuring the steam inlet temperature, if a thermocouple with an upper limit measurable temperature of up to several thousand degrees is attached to the pipe surface, it can be measured without limitation to the high temperature range (high pressure range). In addition, when steam is consumed in a closed path from steam (gas) to return water, the steam consumption can be specified. Therefore, not only the absorption refrigerator 1 as described above, but also steam energy such as a steam-driven turbine or heating equipment is input. It can be widely applied to the measurement of the performance of equipment such as equipment and boiler steam generation.

  Next, an example of actual measurement according to the method described above will be described. First, the steam temperature and the return water temperature of the steam are measured (instantaneous value: measured data). Next, from these measured data, the measured values every minute are averaged every 60 minutes. FIG. 5 shows measured data (instantaneous values) of each of the steam temperature and the return water temperature, and data obtained by averaging measured values every minute every 60 minutes.

  Next, each enthalpy is obtained from the average value of the steam temperature and the average value of the return water temperature by the above-described conversion formula for specific enthalpy obtained in advance. FIG. 6 shows the steam enthalpy and return water enthalpy determined by this.

  On the other hand, for the return water flow rate, the measured value every minute is averaged every 60 minutes from the actually measured instantaneous value. FIG. 7 shows measured data (instantaneous value) of the return water flow rate (volume flow rate) and data obtained by averaging measured values every minute every 60 minutes.

  Then, the averaged volume flow rate (l / min) is converted into a mass flow rate (kg / min) based on a known water temperature and specific volume relationship of water. The volume flow before conversion and the mass flow after conversion are shown in FIG.

  Next, by multiplying the difference between the steam enthalpy and the return water enthalpy by the return water flow rate (mass flow rate) after the conversion, the heat amount (energy) of the input steam can be obtained. FIG. 9 shows the amount of steam heat obtained by these series of measurements and calculations.

  The above is an example of obtaining the heat quantity (energy) of steam input to the absorption refrigerator 1 as an example of the equipment to be measured. However, the present invention is not limited to obtaining such input energy. , It is possible to determine the steam flow itself after the energy is consumed.

That is, as shown in FIGS. 7 and 8, first, the volume flow rate of the steam return water is measured with an ultrasonic flowmeter for liquid, averaged, and then the mass flow rate based on the specific volume relationship between water temperature and water. It is possible to obtain the steam flow rate after consuming the energy. Therefore, it is possible to easily measure the flow rate of steam after consumption of steam energy, even for various equipment that has a condenser such as a condensing trap that operates intermittently in a closed pipe line through which steam flows. .
In the conversion of mass flow here, the specific volume of water may be set in advance from the return water temperature in the specifications of the equipment. Since the error in conversion due to this is about 3 to 4%, there is no practical problem in measurement that does not require higher accuracy. This also eliminates the need for measuring the return water temperature and saves steam flow.

  INDUSTRIAL APPLICABILITY The present invention is useful for measuring input energy and measuring steam flow of various equipment using steam as an energy source.

It is explanatory drawing which shows the piping surrounding the absorption refrigerator for implementing embodiment, and the installation condition of main apparatuses. It is a figure which shows the conversion formula of the relationship between steam temperature-steam enthalpy, and steam enthalpy. It is a figure which shows the conversion formula of the relationship between steam return water temperature-return water enthalpy, and the return water enthalpy. It is a graph which shows the comparison result of the measurement result of the steam flow rate by the piping insertion type vortex steam flow meter, and the measurement result of the steam flow rate according to the present embodiment. It is a time series graph of steam temperature, instantaneous value of steam return water temperature, and averaged data. FIG. 6 is a time series graph of steam enthalpy and return water enthalpy obtained from the average value of steam temperature and the average value of return water temperature in FIG. 5. It is the time series graph of the data which averaged the measurement data (instantaneous value) of the return water flow rate (volume flow rate) of a return water flow rate, and the measured value for every minute for every 60 minutes. FIG. 8 is a time series graph of mass flow rate and volume flow rate based on the averaged data of FIG. 7. FIG. It is a time series graph of the amount of steam heat calculated based on the data of FIGS.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Absorption refrigeration machine 2 Regenerator 3 Condenser 4 Absorber / evaporator 11, 12 Piping 13 Automatic valve 14 Condensation trap 15 Vertical pipe 16, 17 Temperature sensor 18 Temperature logger 19 Ultrasonic flow meter

Claims (7)

A method of measuring steam energy input to equipment using steam,
Measuring the temperature of the steam flowing into the equipment and determining the inlet-side steam enthalpy;
Measuring the temperature of the steam return water from the equipment to determine the outlet side steam enthalpy;
Obtaining the flow rate of the steam return water by means of an ultrasonic flowmeter for liquid attached to the surface of the pipe through which the steam return water from the equipment flows.
Further, subtracting the outlet-side steam enthalpy from the inlet-side steam enthalpy, and multiplying the result by the flow rate of the steam return water to obtain the steam energy input to the equipment, Measurement method. The method for measuring input energy of equipment according to claim 1, wherein the ultrasonic flowmeter for liquid is attached to a surface of a vertical pipe through which steam return water flows. The flow rate of the steam return water is obtained by averaging the return water flow rate data measured as an instantaneous value to obtain the return water flow rate. To measure the input energy of the equipment in Japan. The method for measuring the input energy of equipment according to any one of claims 1 to 3, wherein a thermocouple is used to measure the temperature of the steam flowing into the equipment. A method for measuring steam flow after energy consumption from equipment that uses steam energy,
The steam after consuming the energy is led out from the equipment through a sealed line,
The closed pipe is provided with a condensing device for changing the phase of the steam into steam return water,
An ultrasonic flow meter for liquid is attached to the surface of the pipe through which the steam return water after the phase change by the condensing device flows,
A method for measuring a steam flow, characterized in that the steam flow after energy consumption is obtained based on the return water flow measured by the liquid ultrasonic flowmeter. The return water flow rate measured by the ultrasonic flowmeter for liquids is the mass flow rate divided by the specific volume of water obtained by averaging the volume flow rate over time and then calculating the average return water temperature. The method for measuring a steam flow rate according to claim 5. The method for measuring a vapor flow rate according to claim 5 or 6, wherein the ultrasonic flowmeter for liquid is attached to a surface of a sealed pipe line of a vertical pipe through which steam return water flows.

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