CN201034751Y

CN201034751Y - Heat distributed measuring device

Info

Publication number: CN201034751Y
Application number: CNU2007201034176U
Authority: CN
Inventors: 方滨; 李盛林; 王玉玺
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2007-02-01
Filing date: 2007-02-01
Publication date: 2008-03-12
Anticipated expiration: 2017-02-01

Abstract

A heat allocating measurement device is provided to measure the heat flux of each radiator of a heating system, which belongs to the heat measurement field. The device includes a single chip (1), a simulating calculation amplifier (2), a thermocouple (3), a communication circuit (4) and a power (5). The two output terminals of the thermocouple (3) are jointed with the two input terminals of the simulating calculation amplifier (2) which can amplify the thermal potential signal. The output terminals of the simulating calculation amplifier (2) are jointed with the simulating input terminal of the single chip, which sends the amplified thermal potential signal to the analog-to-digital converter of the single chip to change into the digital signal. The communication circuit (4) is connected with the serial interface of the signal chip by a data interface, which sends the measured data to outside and receives the setting instruction. The power (5) is connected with the power of each device to supply power. The device can get the heat flux of each radiator more accurately with low cost, which is applicable for any form of radiators with the same specification.

Description

Heat distribution metering device

Technical Field

The utility model relates to a device of heat distribution measurement for measure the heat flow of every radiator among the heating system, belong to the heat measurement field.

Background

Riser downstream piping structures are currently widely used in existing residential heating systems. In the house with the structure, each household has more than one water inlet and outlet, and the household metering needs to be carried out by additionally arranging a heat meter on each radiator in each household, so the cost is very high. Another solution is to modify the pipeline structure so that each household has a uniform hot water inlet and outlet, but the modification of the pipeline structure is expensive and can destroy the original interior decoration. The method for solving the household heat metering problem of the residential building with the structure generally adopts a heat distribution metering method.

The heat distribution metering method does not directly measure the heat dissipation capacity of each radiator, but measures the heat dissipation capacity of the whole system by using a building heat meter, measures the percentage of the heat dissipation capacity of each radiator in the heat dissipation capacity of the whole system by using the heat distribution meter, and obtains the actual heat dissipation capacity of each radiator through apportionment calculation. Two approaches have been used in the past, evaporative heat distribution tables, and the later emerging electronic heat distribution tables. The evaporative heat distribution meter is arranged on the surface of the radiator, certain chemical liquid is pre-filled in the meter, and the liquid is heated and then volatilized, and escapes out through the pores. The evaporation rate of the liquid is closely related to the surface temperature of the heat sink, and the liquid evaporates more rapidly the higher the surface temperature of the heat sink is. After the heating season is over, the apportionment ratio is calculated by recording the amount of liquid left in each heat distribution table, and the cost to be shared by each radiator is obtained. The evaporative heat distribution meter must be filled with chemical liquid before each heating season begins, data cannot be remotely transmitted, manual meter reading is needed, and the evaporative heat distribution meter is troublesome to use. The electronic heat distribution meter basically simulates the function of an evaporative heat distribution meter, replaces chemical liquid with an electronic device and a temperature sensing element, increases a remote transmission function and avoids the defects of the evaporative heat distribution meter. However, in both the evaporation type and the electronic type, the temperature of the surface of the radiator is taken as the measurement basis, and the indication value of the temperature cannot truly reflect the relationship with the heat flow of the radiator.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the heat distribution metering device that the heat dissipation capacity of calculating the radiator at present adopted all uses radiator surface temperature as the measurement foundation, and the defect of the unable truly relation between reflection and the radiator heat flow of its indicating value, the device of a new heat distribution measurement that provides is applicable to any form with the specification radiator, and the indicating value is closer to actual radiator heat flow more.

The device of the utility model, see fig. 1, contains singlechip 1, analog operational amplifier 2, thermocouple 3, communication circuit 4, power 5. Two output ends of the armored thermocouple 3 are connected with two input ends of the analog operational amplifier 2, and the analog operational amplifier 2 amplifies weak thermoelectric potential signals; the output end of the analog operational amplifier 2 is connected with the analog input end of the singlechip, and the amplified thermoelectric potential signal is sent to an analog-to-digital converter of the singlechip to be converted into a digital signal; the communication circuit 4 is connected with a serial interface of the single chip microcomputer 1 through a data interface, and sends measurement data to the outside and receives a set instruction; the power supply 5 is connected to and supplies power to each device in the apparatus.

And the communication circuit for sending the measurement data is connected with the total heat meter through a network. Total heat meter passing networkCollecting thermoelectric voltage signals generated on all radiators in the system according toi =1.. M, the shared heat flow for each radiator is calculated.

The principle of the present invention is based on the following facts: if a certain quantity (simply called characteristic quantity) of the radiator is in direct proportion to the heat flow of the radiator (the proportionality coefficient is called characteristic quantity coefficient), the method can be adopted

Calculating the heat dissipation amount of each heat sink, wherein _i Is the heat dissipation capacity of the ith radiator, phi is the total heat dissipation capacity of the system, N _i Is the heat dissipation amount phi of the ith radiator _i And (4) performing heat sharing calculation on the proportional characteristic quantity. The principle of heat transfer can prove that under most operating conditions, the temperature difference between the water temperature of the water inlet of the radiator and the temperature of the air nearby is in direct proportion to the heat flow of the radiator, and therefore the temperature difference of the water and the air can be used as a characteristic quantity to carry out heat sharing calculation.

The basic principle of thermocouples is known to measure temperature differences. Within the operating regime of the heating system, it can be considered that the thermoelectric potential generated by the thermocouple is proportional to the temperature difference between the working and cold ends. If the thermocouple is used to measure the water-air temperature difference of the radiator directly, that is, the working end of the thermocouple is inserted into the water inlet to measure the water temperature of the inlet, and the cold end is not compensated like the conventional application but directly exposed to the air near the water inlet, the thermoelectric force generated by the thermocouple will be proportional to the temperature difference between the water temperature at the water inlet of the radiator and the air temperature near the water inlet, and therefore, the thermoelectric force generated by the thermocouple will also be proportional to the heat flow of the radiator, and therefore, the thermoelectric force generated in this way can also be used as the characteristic quantity.

Obviously, a heat distribution meter manufactured according to the above principle is installed on each radiator, the characteristic quantity of the radiator is measured, and the heat metering of each radiator can be realized according to the apportionment metering principle by matching with a building total heat meter. Fig. 2 is an overall block diagram of the heat distribution metering system.

The low realization cost is a great advantage of the device. In a large number of old buildings using a riser downstream heating structure at present, the measuring device can be additionally arranged on each radiator, the cost is not high, and the measuring device is very suitable for distributing and metering heat among households in a building. Because the types of the radiators are the same, the characteristic quantity coefficient does not play a role in the whole apportionment metering process, so that the coefficient determination problem does not exist, and the method can be applied to radiators with the same specification in any forms.

The process is the test that SYTLZ-A-2-1.2's copper aluminium composite heat radiator and four post 813 type cast iron radiators go on to the model, obtains the thermoelectric force of the K type thermocouple of actual measurement and the experimental curve of heat flow, as shown in figure 3 and figure 4, the theory that experimental result and thermoelectric force and heat flow are direct proportional relation coincide better, and then has proven the utility model discloses a heat distribution measurement's device can be more accurate the heat flow that obtains every radiator.

FIG. 5 shows the relative error distribution between the measurement of the present apparatus and the direct measurement of other gauges. It can be seen from the figure that under various working conditions, the measurement error between the heat flow measured by the device and the heat flow directly measured by the meter can be basically controlled within 10%.

Drawings

FIG. 1 is a block diagram of a thermal flow metering device system, wherein:

1. singlechip, 2, analog operational amplifier, 3, thermocouple, 4, communication circuit, 5 and power supply

FIG. 2 is a block diagram of the heat distribution metering system

FIG. 3 is a curve of a copper-aluminum composite radiator (flow 400 kg/h)

FIG. 4 experimental curve of four-column 813 type heat sink (flow 400 kg/hr)

FIG. 5 relative error distribution of the present apparatus and the direct measurement of the meter

Detailed Description

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings:

the singlechip 1 in the device is PIC10F220 of American micro-core company. The analog operational amplifier 2 employs the SGM8522. The device uses battery power supply, power supply voltage stabilization chip

TPS60213 was used. Communication electric applianceWay 4 uses MAX3471. The thermocouple 3 for water inlet temperature measurement is a K-shaped sheathed thermocouple with threads, and the model is WRNK-206. In use, a thermocouple measuring the inlet water temperature is connected to the water inlet line of the radiator to be tested, with the cold end exposed to the ambient air.

An 8-bit analog-to-digital converter is integrated in the single chip microcomputer 1, and the analog input of the analog-to-digital converter is connected with the output end of an analog operation amplifying circuit for measuring the water inlet temperature. The program in the singlechip 1 simulates a serial communication interface and forms an RS-485 serial communication circuit 4 with MAX3471 through a general I/O port.

When the system works, in a working period, the total heat meter polls each heat distribution meter respectively, after a single chip microcomputer 1 in the heat distribution meters receives a polling request, amplified thermal potential analog input which is proportional to the temperature difference of water and air is sampled and converted, and the single chip microcomputer 1 directly sends digitized thermal potential analog values to the total heat meter through a serial communication circuit 4. After receiving the data sent by all M heat distribution meters, the total heat meter is used for calculating the total heat distribution meter according to the formula

And calculating the heat flow of each radiator, and obtaining the heat consumed by each radiator after integrating the heat flow with time.

In the present embodiment, the duration of the duty cycle of the system is 120 seconds.

Claims

1. A heat distribution metering device, characterized by: the device comprises a singlechip (1), an analog operational amplifier (2), a thermocouple (3), a communication circuit (4) and a power supply (5); the two output ends of the thermocouple (3) are connected with the two input ends of the analog operational amplifier (2), and the analog operational amplifier (2) amplifies a thermal potential signal; the output end of the analog operational amplifier (2) is connected with the analog input end of the singlechip, and the amplified thermoelectric force signal is sent to an analog-to-digital converter of the singlechip and is converted into a digital signal; the communication circuit (4) is connected with a serial interface of the singlechip (1) through a data interface, and is used for sending measurement data to the outside and receiving a set instruction; the power supply (5) is connected with and supplies power to each device in the device.

2. A heat distribution metering device as set forth in claim 1 wherein: the communication circuit (4) is connected with the total heat meter through a network, and the total heat meter calculates the apportioned heat flow of each radiator through thermoelectric potential signals generated on all radiators in the network acquisition system.