RU2348061C1 - Automatic building heating adjustment system with automatic setup unit - Google Patents

Abstract

FIELD: physics, control.

SUBSTANCE: invention concerns sphere of temperature control and adjustment systems by electric means and can be applied in automatic adjustment systems (AAC) for heating buildings with central water heating for solving issues of energy saving. Adjustment system includes outside air temperature sensor and automated setup unit forming setup signal on the basis of two incoming signals and initiating control action for AAC according to the results of comparison of current system state to setup signal. Adding these elements allows for system flexibility in relation to outside climatic factors without additional build-up of adjustment fittings.

EFFECT: heat energy saving due to heat carrier temperature adjustment in accordance with outside air temperature.

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Description

The invention relates to the field associated with control systems and temperature control by electrical means, and can be used for automatic control systems (CAP) for heating buildings with central water heating to solve energy saving problems.

A known system of automatic regulation (CAP) of heating a building using a heat exchanger (Livchak V.I. Energy conservation in district heating systems at a new stage of development // Energy conservation, 2000. No. 2. - P.4-9), containing individual water in heat point (ITP) heat meter (designated as ТС - heat meter), consisting of 2 temperature sensors, a heat carrier flow meter and a heat meter, a direct-acting differential pressure regulator, a control valve with an actuator connected to the regulator, Representing a thermostat with the clock input of which is connected to a temperature sensor, a heat exchanger, circulation pump, heating devices in the building heating system with thermostats, expansion tank with a safety valve.

The main disadvantage of this technical solution is the low efficiency of CAP heating of buildings, since the temperature schedule of the coolant supply from heating networks, the temperature of the outdoor air and the temperature inside the building are not taken into account.

The prototype of the invention is a building heating CAP taking into account climatic factors (RU 2247422 C1, 2004, "Building heating CAP taking into account climatic factors"). This CAP contains a local controller (LK), an immersion temperature sensor for the coolant, and temperature sensors for external and internal air, located respectively on one of the external facades of the building and indoors from this facade, connected to the inputs of the LC from 1 to 3. On the pipelines of the heating system Installed: a control valve connected to external heating networks, a circulation pump and a jumper with a check valve between them connecting the supply and return pipelines. The actuator of the control valve and the electric circulating pump are connected to 1 and 2 outputs of the LC. In addition, CAP has additional control valves and air temperature sensors. CAP contains an additional controller (DC) and hydraulic distributors with branches of the heating system along the facades of the building, and on all or several supply or return branches covering the facades of the building with the exception of the north, additional control valves with actuators 1 through m are installed. In addition, additional external temperature sensors from 1 to j and internal from 1 to i of air are located on the remaining external facades and one in the premises of each of the building facades covered by branches with additional control valves. In addition, the actuators 1 to m are connected to the outputs of the DC from 1 to m, and the temperature sensors for the outdoor air from 1 to j and the indoor air from 1 to i are connected to its corresponding inputs from 1 to (j + i) or through a communication adapter to 1 digital communication port (DPC) of the DC, while 2 DPCs of the additional controller are connected to the DPC of the local controller.

The main disadvantage of the above solution is the need to install additional temperature sensors inside the heated room and control valves for each of the building facades and an additional DC controller, which is often economically inexpedient for buildings of short length and buildings whose heat loss slightly depends on the direction and speed of the wind and the position of the sun on skyline during the heating season.

The technical result is the saving of thermal energy by regulating the temperature of the hot fluid in accordance with the temperature of the outside air.

The technical result is achieved by the fact that the proposed building heating CAP contains an automated controller that generates a reference signal based on two input signals, and then, by comparing the current state of the system and the reference signal, initiates a control action for the system.

The building heating CAP is shown in FIGS. 1 and 2. FIG. 1 shows a block diagram of a building heating with its own boiler room; therefore, an additional control loop with a heat load regulator and a regulating body affecting fuel consumption in the boiler furnace is introduced into the CAP. Figure 2 shows a diagram of automatic regulation of heating of a building from a city heating system. Figure 3 shows the structure of the automatic master.

The proposed CAP contains an additional outdoor temperature sensor - 1, TV - a signal that sets the temperature in the room - 2; ZD - automatic adjuster - 3; adders - 4 and 7; RTsv - temperature regulator of direct network water - 5; PO ₁ - regulatory body that affects the flow of heat into the heating system (Q ₁ ) - 6; PTH - heat load regulator - 8; PO ₂ - regulatory body that affects fuel consumption (W) in the boiler furnace - 9; regulation subject - 10; W _UK - device for compensating external disturbances - 11; µ is the vector of external disturbances affecting the temperature of the direct network water (Тсв) (necessary in the case of a significant influence of external factors on Тсв); Q ₂ - the current amount of heat entering the control object.

The signal from the outdoor temperature sensor 1 and the signal 2, which sets the room temperature, are fed to the input of the setter 3, where a reference signal is generated, which represents the required temperature of the hot water in the heating circuit. Then the signal goes to the adder 4, where the current temperature in the circuit is subtracted from it. Next, the mismatch signal is fed to the input of the controller 5, which generates a control signal and directs it to the regulating body PO ₁ 6, which acts on the heat flux into the heating circuit. On the adder 7, the following occurs: the mismatch signal for RTsv 5 is formed as the difference between the reference signal (ZD) 3, presented as the amount of heat required to maintain a given temperature in the circuit (comes from the output of RTsv 5), and the heat signal supplied to the circuit at the current moment is Q ₂ . In addition, it is also possible to take into account external disturbance if it significantly affects the adjustable parameter (for example, the outdoor temperature must be included here with a large length of heating systems). The mismatch signal, formed in this way, then goes to the input of the heat load controller PTH 8, at the output of which a control action is generated for the regulator PO ₂ 9, which affects the fuel consumption in the boiler furnace. Further, the change in fuel consumption leads to a change in the state of the control object 10, characterized by the parameters Q ₂ and T _St. (figure 1) or only T _St. (figure 2). The circuit in figure 2 works similarly.

The structure of the automatic master is based on the following procedure.

The amount of heat lost by the building into the environment and compensated by heating devices is generally determined by the formula:

where Q _TP - the amount of heat lost by the building through the building envelope;

Q _veins - the amount of heat required to heat the supply ventilation air;

Q _tv - the amount of heat released in the building from working machines and devices.

where A _i - the area of the enclosing structures;

R _0i - thermal resistance of building envelopes;

t _in , t _n - temperature of internal and external air;

n is a correction factor that takes into account corrections for the orientation of the building, for the presence of external walls, doors, etc.

On the other hand, the amount of heat to compensate for heat loss:

where q ₀ - specific heat loss, depending on the functional purpose and volume of the building,

V _health - the volume of the building for external measurement.

The numerical values of q ₀ (V), t _in , t _n are widely represented in the reference literature, in particular in SNiP 2.04.07.

Also, specific heat losses can be tentatively determined by the empirical formula:

where n = 6; а = 1.98 kJ / (s · m ^2.83 · ° С) for buildings built before 1958,

n is 8; а = 1.51 kJ (s · m ^2.83 · ° С) for buildings built after 1958

The correction factor ψ has the following values depending on the values of the calculated temperatures for heating:

when t _n > -10 ° C ψ = 1.2;

at t _n = -20 ° C ψ = 1.1;

at t _n = -30 ° C ψ = 1.0;

at t _n ≤40 ° С ψ = 0.9;

Also, the maximum heat flux can be set by the formula (SNiP 2.04.07):

where q ₀ (F) is an aggregated indicator of the heat flux for heating residential buildings per 1 m ² area, taken in accordance with Table 1.3 (SNiP 2.04.07);

k ₁ - coefficient taking into account the heat flow for heating public buildings; in the absence of data should be taken equal to 0.25;

A is the total area of the heated building.

Using formulas (4-5), we find the maximum heat flux for heating buildings per 1 m ² area. Further, from (3) and the condition of equality of the heat lost by the building Q ₁ and the amount of heat from the heating devices Q _2, we obtain the necessary hot water temperature in the direct line:

where Q ₁ is the heat introduced into the consumer’s buildings with hot water;

And _i is the area of the heating system structures;

R _0i is the thermal resistance of the structures of the heating system;

t _gv , t _in - temperature of direct hot water and air in the consumer’s premises;

where Q ₂ - heat loss of buildings.

To ensure a constant temperature in the room, the following conditions must be met:

* it should be borne in mind that in accordance with (1), in order to increase the calculation accuracy in (8), it is necessary to take into account the heat for heating the ventilation air and the heat from the machines operating in the room.

hence the temperature of the hot water in the direct line:

The parameters of the consumer’s building are constant, the characteristics of the heating devices are practically independent of the temperature difference in the main operating range, therefore, we obtain that t _gv is a function of a single variable - the outdoor temperature t _n . It is used to generate a reference signal for the RTsv controller. For this, the characteristics of the heating devices and the calculated parameters of the consumer building q ₀ (V) and V _{building are used} .

Thus, in accordance with (9), the structure of the setter will have the form (Fig. 3).

T _in and T _n - signals for air temperature inside and outside the room. Moreover, the signal T _in is the control, a change in its value leads to a change in temperature inside the premises. The signal T _n is corrective; it adapts the system to changes in the ambient temperature.

SUM - block summation.

US - gain block, gain (K) is determined from (9):

A feature of the proposed CAP is that it involves the installation of an additional outdoor temperature sensor and the installation of a device for calculating the reference signal. For this, either a standard computer with a device for converting an analog signal from a temperature sensor to a digital form and vice versa, or a simple controller with similar functions can be used.

Consider the principle of operation of the system in the event of a decrease in outdoor temperature. In this case, the automatic master in accordance with (9) generates a mismatch signal as follows: the signal Tnv - 1 and Tv - 2 are fed to the adder 12, and the Tvv is inverted. After reducing the value of Tin at the output of the adder 12 there will be an increased signal (in comparison with the previous state). Next, this signal will go to amplifier 13, where it will be increased by a factor of K, and then to adder 14, on which TB is added to it, in accordance with (9). From the output of the adder 14, this signal is fed to the adder in front of the RTsv 7, where a signal is generated to open the control valves, which provides an additional heat influx into the consumer's building. In the case when the system has the form of FIG. 1, a signal is additionally generated to open the control valves to supply fuel to the boiler. The inertia of the setpoint controller with such regulation is determined only by the inertia of the outdoor temperature sensor, which ensures high efficiency of the system in controlling the flow of coolant.

Thus, the proposed technical solution is aimed at increasing the efficiency of CAP heating by the building, taking into account climatic factors, by introducing an external air temperature signal into the controller and implementing an algorithm for calculating the optimum temperature of the network water in the direct line.

Claims (1)

An automatic control system for heating a building from a city heating system, comprising an immersion temperature sensor, an outside temperature sensor and control valves with actuators, characterized in that the system includes an automatic controller for generating the required hot water temperature in the heating circuit, with one of the inputs which is connected to an outdoor temperature sensor, and a signal that sets the temperature in the room is received at the other input, while automatically th dial is composed of series-connected first adder configured to inversion of one of the received signals to it, the gain block and the second adder, wherein the sum signal from the amplifier output signal and defining a room temperature.

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