In the era of expensive energy carriers, the economic aspects of heat supply have long become a pressing issue in industry, utilities, even in the economy of each individual family. It is known that a rational and efficient economy must be based on accounting. Accordingly, the economics of heat supply should be based on a qualitative accounting of the produced, supplied and consumed heat energy, or simply - heat.
Purpose and principle of operation of heat meters
A significant (almost overwhelming) number of modern communal or industrial heat supply systems are based on pipeline systems, in which the heat carrier is water. To account for the performance of heating devices or the consumption of thermal energy by consumers in such systems, special metering devices are used - water heat meters.
A modern water heat meter combines the following features:
- multi-parameter instrumentation, in which the measured parameters are: the flow rate of the coolant in the pipeline, as well as the temperature difference of the coolant at the inlet and outlet of the controlled pipeline system;
- a computing and analytical device (controller) that calculates the quantitative consumption of thermal energy, and in some modern digital and computerized models - performs some analytical operations, and also writes statistical information into electronic memory, for the purpose of its further analysis by specialists, even allows you to read it remotely online, via the Internet or radio signals.
Why do we need heat meters in industrial, municipal or domestic heat supply systems? Ultimately, to save heat and energy. But how can a meter actually save heat energy? It is very simple - through the optimization of the behavior of personnel serving the heating system. Knowing the objective indicators of heat consumption, it is already possible to reasonably regulate both the reproduction and supply of heat energy (from the heat supply side) and its consumption (from the subscribers - consumers).
Scope of water heat meters
The areas of application of water heat meters are any pipeline systems that use water as a heat carrier to transfer heat energy from a water heater (boiler, boiler) to consumers:
- TPPs and boiler houses of centralized heating and (or) hot water supply systems, for industrial and municipal purposes;
- industrial technological installations (heat exchangers, reactors, heaters, coolers, etc.), for the control and management of technological processes.
- subscriber inputs of centralized water heating and hot water supply systems for apartment buildings (so-called house heat meters of heating points), office or industrial complexes;
- subscriber inputs of centralized systems for individual apartments and private houses (so-called apartment heat meters);
- local boiler houses and water boilers for heating individual buildings, offices, private houses;
- apartment subscription
Fig. 1 An example of remote readings from heat meters for residential subscriber metering.
Device, scheme of operation of a water heat meter
- With all the variety of designs, the device of any water heat meter can be basically reduced to the following main functional parts (nodes):
- A straight-through body of the appropriate diameter (for the piping system in which it is installed), with connecting pipes of the appropriate type (flanged, coupling (threaded)).
- A flow meter assembly, placed (partially or completely) in the through-flow housing of the device, performing the task of measuring the flow rate of the medium in the pipeline.
- Two thermometers (of which at least one is remote), for measuring the temperature of the coolant at the inlet and outlet pipelines of the heat supply system.
- The computational and analytical unit (calculator), into which the fixed parameters of the flow diameter of the controlled pipeline, the heat capacity of the coolant are entered, and dynamically variable information is received from the thermometers and the flow meter. Based on fixed parameters and variable data, the calculation block produces:
a) calculation of the volumetric flow rate of the coolant;
b) calculation of the quantitative consumption of thermal energy per calculated unit of time;
c) quantitative summation of heat consumption for the accounting period;
d) issues the corresponding digital indication, performs other calculation and analytical operations.
As a rule, a heat meter is installed on the supply (injection) pipe of the heat supply system. With the beginning of the supply of the coolant to the consumer, the flow meter measures the actual flow rate in the pipe, and the thermometer measures its initial temperature (at the inlet to the local circuit of the consumer). After passing through the heat supply circuit of the consumer, the cooled heat carrier enters the outlet (return) pipe, where its final temperature is measured by a second (usually a remote) thermometer. Information from the flow meter and thermometers enters the calculation and analytical unit, which performs the corresponding calculations, provides indication and storage of their results.
Types of heat meters
The existing designs of heat meters are distinguished according to the principle of operation of the flow meter unit and the calculator unit.
According to the principle of operation of the flow meter, heat meters are:
1) Mechanical. In them, the flow rate of the coolant is measured by taking the number of revolutions of the impeller or turbine placed in it. This is the simplest and cheapest design, but it has a limited working life and measurement errors that grow over time, caused by "fouling" of the impeller or turbine with oxides, scale and other deposits.
2) Ultrasonic. Their principles of operation (there are several of them) are based on measuring different parameters of ultrasound transmission (transit time, frequency change, amplitude) between the emitter and the receiver, which are located in the coolant flow. Ultrasonic heat meters are quite reliable and durable, show good accuracy and stability of measurement results, working in modern heating systems. Today it is the most optimal heat meter for general house and apartment-based heat energy metering systems.
3) Electromagnetic. Their principle of operation is based on the ability of an electrically conductive liquid (water) to excite an electric current when it passes through an electromagnetic field (the phenomenon of electromagnetic induction). This design is based on an electromagnet, which creates an electromagnetic field in the flow of the medium, and a sensitive potentiometer, which measures the electrical potentials arising at the spaced electrodes. Electromagnetic flowmeters show very good measurement accuracy and stability in a clean environment contaminated with non-magnetic clay particles in an airborne system. A factor that can introduce errors in measurements is water pollution by magnetic particles, mainly by corrosion scale from the walls of pipelines. Also, electromagnetic heat meters dealing with small measured currents are very sensitive to the quality of their installation.
4) Vortex. They are essentially a combination of mechanical and electromagnetic flowmeters. The vortex flowmeter has a prism located inside the coolant flow and a potentiometer based on a permanent magnet. The flow of liquid, flowing around the prism, forms vortices periodically breaking off from its surface, which cause changes (oscillations) of the electromagnetic field. The higher the flow velocity of the medium, the higher the frequency of vortex formation on the prism, the higher the fixed frequency of the magnetic field oscillation.
According to the principle of operation of the calculator unit, heat meters are:
- analog - allow you to fix the current value of thermal power, and the total value of the consumption of thermal energy for the period;
- digital - among other things, they allow you to record statistical information on a digital medium (memory) for its subsequent in-depth analysis;
- computerized - among other things, they allow you to program the operation of a heat meter (usually associated with a shut-off and control valve) and remotely monitor the operation of the system in real time (online).
Separately, it is necessary to highlight the devices manufactured by Qundis and allowing to take readings of the heat energy consumption from the radiators of heating systems. These are the so-called distributors (recorders) of heat energy Q caloric. These devices allow you to take readings of the heat consumption of radiators, regardless of the type of pipe routing of risers in the apartment.
Heat meters QUNDIS (Made in Germany)
OPEKS Energosystems is the official representative of the authoritative German company QUNDIS GmbH, which holds a strong position in the European market of heat meters, whose products are characterized by impeccable, guaranteed quality.
The company's warehouse has both mechanical and ultrasonic heat meters for apartment metering. We cooperate with many installation companies and private customers who install meters at the consumer.
The pricing policy for all devices is loyal and satisfies our customers.
Both Qheat mechanical and ultrasonic heat meters from Qundis are certified for use and have a calibration interval of 4 years.
Heat meters Qundis are widely used for apartment metering. They are favorably distinguished by high German workmanship at an affordable cost, reliability and long service life, about 10 years without replacing the battery.
Order QUNDIS heat meters from the official certified importer - OPEKS Energosystems!