JPS6142100Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an electronic calorimeter, in particular, it calculates the heat conversion coefficient based on the temperature of the heat medium, and also calculates the heat flow rate,
Cumulative volume, flow rate, temperature difference, inlet temperature, outlet temperature,
This invention relates to an electronic calorific value measuring device that calculates various functions such as the amount of heat used above the contracted heat flow rate.

By the way, in district heating and cooling energy centers and building air conditioning monitoring rooms that perform centralized heat management and control, it is necessary to accurately understand the efficiency of heat sources.
Therefore, it is necessary to correct the heat conversion coefficient, which varies depending on the type and temperature of the heat medium. Recently, liquids other than water are often used as heat media, and monitoring and control of such liquids has become difficult due to issues such as ensuring safety when used at high temperatures, optimal control of air conditioning systems, and energy conservation. More stringent requirements are required to monitor and control heat sources and consumption equipment, and in addition to monitoring and controlling heat sources and consumption equipment, it is necessary to monitor and control heat flow, integrated volume, flow rate, temperature difference, inlet temperature, outlet temperature, or customer's contract heat. It is becoming extremely important and necessary to accurately know the amount used above the flow rate. Conventionally, various calculation methods have been proposed for integral calorimeters, but most of them only calculate the integral calorific value, and their configuration is based on a single function, so other functions are required. However, there were drawbacks such as the fact that it was not easy to manufacture.

The present invention was made in view of the above problems, and by connecting two resistance thermometers in series, it is possible to obtain the inlet temperature of the heating medium and the temperature difference between the inlet and outlet with high accuracy, and to obtain the temperature difference between the inlet temperature and the inlet and outlet. An object of the present invention is to provide an electronic calorific value measuring device that can accurately obtain various types of information necessary for optimal control of an air conditioning system, etc. with a simple configuration by converting the difference from analog to digital and performing arithmetic processing. , its characteristics are that a constant current is supplied from a constant current circuit, and a resistance thermometer is connected in series at the inlet and outlet of a device that uses fluid as a heat medium, and the temperature between the inlet and outlet is A subtraction circuit for detecting the difference, a switching means for switching between the output of the subtraction circuit and the output of the inlet side temperature measuring resistor, and a flow rate signal generator for generating a flow rate signal by generating one pulse per unit volume of heat medium. and a voltage-to-digital conversion circuit which converts the output signal of the switching means into a digital signal, converts the temperature difference signal into a digital signal as a heat quantity signal every time a flow rate signal is input, and outputs the flow rate signal as it is; Based on the digital signal and flow signal, the integrated heat amount,
Perform predetermined calculations to obtain heat flow rate, integrated volume, flow rate, temperature difference between inlet and outlet, inlet and outlet temperatures, amount used above the contracted heat flow rate, etc., and convert the inlet temperature obtained by switching the switching means into heat amount. It consists of a calculation control circuit for calculating coefficients, and a display means for displaying the cumulative amount of heat and the like based on the output of this calculation circuit.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

A constant current from the constant current circuit 1 is supplied to resistance temperature sensors 2 and 3 made of nickel, platinum, copper, etc.
The detected temperatures are each input to a subtraction circuit 4 and converted into an electric signal DS proportional to the temperature difference between the inlet and the outlet. This electrical signal DS is transferred to the changeover switch 16.
The signal is then input to the voltage-to-digital converter circuit 5 and converted into a digital signal indicating the temperature difference. Further, the flow rate signal FS from the flow rate signal generator 7 which generates one pulse per unit volume of the heat medium is also input to the voltage-digital conversion circuit 5, and this flow rate signal is
When FS is input, both are multiplied to obtain a digital signal PD indicating the amount of heat in the heat medium.

On the other hand, an electric signal TS proportional to the inlet temperature obtained by switching the changeover switch 16 is also input to the voltage-digital conversion circuit 5 and converted into a digital signal PD indicating the inlet temperature.

Note that the voltage-digital conversion circuit 5 uses only one A-D converter, so the output digital signal PD is a calorific value signal when the flow rate signal FS is input, and is a calorific value signal at other times. It is a temperature difference signal, and when the changeover switch 16 is switched, it is an inlet temperature signal.

The various digital signals PD are input to a calculation control circuit 6 composed of a microcomputer, and the amount of heat, etc. of the heating medium is determined by digital calculation according to a predetermined program calculation, and the results are sent to an integrated amount of heat indicating device 8. , a heat flow rate indicator 9, an integrated volume indicator 10, a flow rate indicator 11, a temperature difference indicator 12, an inlet temperature indicator 13, an outlet temperature indicator 14, and a usage amount indicator that indicates usage above the contract heat flow rate. 15 respectively.

The calculation control circuit 6 switches the changeover switch 16 so that the input to the voltage-digital conversion circuit 5 is the temperature difference between the heat medium at the inlet and the outlet, or the temperature at the inlet of the heat medium. In addition, the resistance temperature detectors 2 and 3 are arranged at the inlet and outlet of a heat medium such as a radiator, respectively, and the calculation control circuit 6 calculates the heat amount conversion coefficient of the heat medium according to the temperature, and calculates the heat flow rate from this. A program for calculating etc. is stored in advance.
Further, the flow rate signal FS is directly outputted from the voltage-digital conversion circuit 5 to the calculation control circuit.

In such a configuration, the resistance temperature detectors 2 and 3
are connected in series, so the current flowing through them is the same, and the drift of constant current circuit 1 affects resistance temperature detectors 2 and 3 at the same rate, so this drift can be reduced to a negligible level by subtraction circuit 4. Reduced. This is particularly effective when the temperature difference is small. Therefore, the temperature at the inlet and outlet is the resistance temperature detector 2.
and 3, an electrical signal DS corresponding to the temperature difference is obtained by a subtraction circuit 4, and this electrical signal DS is inputted to a voltage-to-digital conversion circuit 5 via a changeover switch 16. On the other hand, the flow rate signal FS from the flow rate signal generator 7 is also input to the voltage-digital conversion circuit 5, and when this flow rate signal FS is input, the electric signal DS is A-D converted to obtain a digital signal PD indicating the amount of heat. . Note that since the flow rate signal FS is one pulse generated per unit volume of the heat medium, it is an electric signal that is converted from A to D.
Since DS is the product of the temperature difference between the inlet and outlet and the flow rate, the digital signal PD indicates the amount of heat at that time.

The digital signal PD indicating the amount of heat, the temperature difference, and the digital signal PD indicating the inlet temperature are input to the calculation control circuit 6, and according to a pre-stored program, the digital signal PD indicating the inlet temperature is first converted into a digital signal PD indicating the inlet temperature.
Determine the heat conversion coefficient of the heat medium using PD.

Next, a digital signal indicating the amount of heat per unit volume
The PD is added, multiplied by a heat conversion coefficient based on the inlet temperature as necessary, and the result is output in a unit suitable for the cumulative heat amount indicating device 8 to indicate the cumulative heat amount.

Thereafter, in order, the calculation control circuit 6 measures the time between pulses of the flow signal FS, divides the digital signal PD indicating the amount of heat by this time, multiplies the amount of heat conversion coefficient as necessary, and converts this value into one hour. Alternatively, it is converted per minute and output to the heat flow indicator 9. The flow rate signal FS is counted and outputted as a unit suitable for the integrated volume indicating device 10. The flow rate signal FS is integrated for a predetermined period of time, and this integrated value is further converted into per hour or per minute, and the flow rate of the heat medium is output to the flow rate indicating device 11. Digital signals PD indicating the temperature difference and the inlet temperature are output to the temperature difference indicating device 12 and the inlet temperature indicating device 13, respectively. The outlet temperature is calculated by adding or subtracting the digital signal PD indicating the temperature difference and the digital signal PD indicating the inlet temperature, and outputs it to the outlet temperature indicating device 14. The amount of heat for which the heat flow exceeds the contracted heat flow is integrated and output to the usage amount indicating device 15.

Note that when the heat conversion coefficient is approximately equal to 1, such as during cooling, the digital signal PD indicating the heat amount is
is the amount of heat as it is, and when the heat amount conversion coefficient needs to be corrected, such as during heating, the calculation control circuit 6 corrects it using the digital signal PD indicating the inlet temperature to obtain the amount of heat.

In this way, according to the present invention, it is possible to obtain various types of information necessary for optimal control of an air conditioning system with a single calorimeter, and also by connecting a resistance temperature detector in series with a constant current circuit. By calculating the heat conversion coefficient from the inlet temperature, the various information mentioned above becomes highly accurate despite the simple configuration.
It has the advantage of being inexpensive to manufacture and extremely practical.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is.

[Brief explanation of the drawing]

The drawing is a block diagram showing an embodiment of the present invention. 1... Constant current circuit, 2, 3... Resistance temperature sensor, 4
... Subtraction circuit, 5 ... Voltage-digital conversion circuit, 6 ... Calculation control circuit, 7 ... Flow rate signal generator, 8 ... Integrated heat amount indicator, 9 ... Heat flow indicator, 10 ... Integrated volume Indicator, 11...Flow rate indicator, 12...Temperature difference indicator, 13...Inlet temperature indicator, 14...Outlet temperature indicator, 1
5... Usage amount indicating device, 16... Changeover switch,
DS, TS……Electrical signal, FS……Flow rate signal, PD
...Digital signal.

Claims (1)

[Scope of utility model registration request] A constant current is supplied from a constant current circuit, and the temperature difference between the inlet and outlet is detected by a resistance thermometer connected in series, which is installed at the inlet and outlet of a device that uses fluid as a heat medium. a subtraction circuit for switching, a switching means for switching between the output of the subtraction circuit and the output of the inlet-side temperature measuring resistor, a flow rate signal generating device for generating a flow rate signal by generating one pulse per unit volume of the heat medium; a voltage-to-digital conversion circuit that converts the output signal of the means into a digital signal, converts a temperature difference signal into a digital signal as a heat quantity signal every time a flow rate signal is received, and outputs the flow rate signal as it is; Based on the flow rate signal, the integrated heat amount, heat flow rate, integrated volume,
A calculation control circuit that performs predetermined calculations to determine the flow rate, the temperature difference between the inlet and outlet, the inlet and outlet temperatures, the usage amount above the contracted heat flow rate, etc., and also calculates the heat conversion coefficient from the inlet temperature obtained by switching the switching means. and a display means for displaying the integrated heat amount, etc. based on the output of the calculation circuit.