UA123256U - Accounting method of heat and device for its implementation - Google Patents

Abstract

The method of accounting for thermal energy in the heating system is based on measuring the flow of the coolant and its temperatures at the inlet and outlet of the heating system. The coolant consumption is determined on the basis of the established fact of self-dependence of dimensionless temperature difference on the elements of thermoelectric generator, which flow in a counterflow scheme with the forward and reverse coolant of the heating system, from the coolant consumption, which allows to uniquely identify the amount of thermal energy consumed by the heat and electricity of the heat and electricity at the inlet and outlet of the heating system.

Description

The proposed method of thermal energy accounting concerns measuring equipment, namely control and measuring devices for heating systems. All known devices for accounting for consumed thermal energy in heating systems use a single principle of measurement, which consists in determining the consumption of the heat carrier Si in the system and the temperature difference between the forward and reverse heat carrier. With the help of these parameters, the power of thermal energy consumption

Gather as ; c (1) where Cho - r -iv. P specific heat capacity of the coolant.

To determine the amount of consumed energy, expression (1) is integrated over time. The most common thermal energy metering devices usually consist of two functional units - a unit for measuring primary parameters (temperature and consumption) and a calculation unit in which primary information is appropriately processed and archived. It should be noted that if temperature measurement does not raise any questions - standardized temperature sensors are used for this, then flow measurement is a more complex problem and is based on the use of devices of various types - tachometric, ultrasonic, electromagnetic, etc., each of which has its own advantages and disadvantages . As a rule, the existing flow measurement systems have acceptable characteristics at a heat carrier flow rate of 0.4 m/sec, while in domestic heating systems the flow rate is usually from 0.1 to 0.5 m/sec, (11.

Another disadvantage of the existing thermal energy accounting systems is the need to connect them to the electrical network to provide power to the electronic unit, which practically makes their use in domestic conditions impossible. In addition, existing metering devices are not at all adapted for use in single-pipe heating systems, which make up the vast majority in existing buildings. All this complicates the use of metering devices in the utility industry and slows down the development of energy-efficient technologies.

The development of thermal energy metering devices using thermoelectric modules capable of operating in autonomous mode is also known. For example, in (|2| a design of a heat meter is proposed, in which the thermoelectric module provides power to the electronic unit. In IZ) a method of accounting for the consumed thermal energy is proposed, based on the measurement of the amount of electricity generated by the thermoelectric module due to the temperature difference between the coolant and the air in the heated room . The last development is closest to the proposed method and is considered as a prototype.

The proposed method of accounting for thermal energy is based on the fact that I established the self-similarity of the dependence of the dimensionless temperature difference on the elements of the thermoelectric generator on the consumption of the heat carrier relative to the initial temperatures of the heat carriers. To explain, consider a thermoelectric generator (TEH), which consists of a thermoelectric module (TM), which flows around coolants with different temperatures according to a counter-flow scheme (Fig. 1). For a TEG of a fixed design, the temperature difference on the thermoelements at-Tj-Tc depends only on the initial temperatures of the coolants and the mass flow rate of the coolant, which determines the flow rate in the channels and the intensity of heat exchange on the module surfaces. Examples of such a dependence for different values of the initial temperatures of coolants are shown in Fig. 2. The analysis of the modes of the TEG scheme under consideration, using the methods of the similarity theory, shows that in the case of reducing the problem to a dimensionless form, the entire array of values of the temperature difference on the module from the flow of the coolant and its initial temperatures is drawn into one generalized curve, and can be represented, regardless of the absolute values of the initial temperatures of the coolants, as follows (Fig. 3):

Thu (2) dla--- de du - dimensionless temperature difference on TM.

That is, the mass consumption of the heat carrier can be unambiguously determined in the form of a function an ; (3) assuming that the thermal EMF of the thermoelectric module is equal to

Co. (5)

Thus, according to (1), the instantaneous value of the consumed thermal power can be determined as:

o - BE ar)Srayu (c) where E and to. parameters that are easily amenable to direct measurements, and the function a-ceao) is a characteristic of the device, which is determined by calibration measurements of the dependence of the thermo-EMF of the thermoelectric module on the consumption of the coolant. Due to the self-similarity of the process, it is sufficient to obtain such a dependence for arbitrary values of temperatures in and is.

The proposed method provides significant advantages over existing thermal energy accounting systems: it does not require the use of flow meters; does not need to be connected to the power grid, since the power supply of the electronic unit can be carried out at the expense of TM power; provides the possibility of measurements at low mass consumption of the coolant; suitable for use in single-pipe heating systems; ensures the necessary accuracy of measurements with small temperature differences; compatible with computing units of existing heat meters.

Sources of information: 1. D.L. Anisimov. Heat energy accounting. -

Nerz /Lymly.arok.tilLog 5res/apisiev.ryr"pia-z029. 2. Method of measuring thermal energy for a certain period of time in water supply and heating systems and a device for its implementation. - Patent of the Russian Federation No. 2536073.

Z. Heat meter. - Patent of the Russian Federation No. 2148803 dated May 10, 2000.

Claims (1)

USEFUL MODEL FORMULA A method of accounting for thermal energy in the heating system, which is based on the measurement of the heat carrier flow and its temperatures at the entrance and exit from the heating system, which is distinguished by the fact that the heat carrier flow is determined based on the established fact of self-similarity of the dimensionless temperature difference on the elements of the thermoelectric generator, which flow around the direct and reverse heat carrier of the heating system according to the counter-flow scheme, from the consumption of the heat carrier, which makes it possible to unambiguously identify the amount of consumed thermal energy by measuring the electromotive force of the thermoelectric generator and the temperatures of the heat carriers at the entrance and exit from the heating system. i S r She drink now tn 0 111 ii. puairaiuvuvi U U U: iz vu yi. I am with T Fig. 1