RU2313730C2 - Method of and device to control operating conditions of heat center at open heat supply system - Google Patents

Abstract

FIELD: heat power engineering.

SUBSTANCE: invention can be used in open heat supply systems of dwelling, public and industrial buildings at dependent system of connection to heating system or for boiler room with group of consumers. Proposed method of control of operating conditions of heat center at open heating system equipped with water-to-water elevator and commercial heat energy metering unit includes. Delivery of system into heating system and hot water supply by adding heat carrier from return pipeline through stimulating-mixing pump. Ratio of flow rates of system and additional heat carrier is changed by drive of centrifugal pump, head of additional heat carrier is raised over head of conventionally constant head of system water in delivery pipeline, and designed heat consumption of object is maintained. Additional heat carrier is taken from zone of flow in return pipeline at minimum dynamic head of system water at wall of pipe and is delivered to zone of maximum dynamic head of system water in delivery pipeline in center of pipe. Invention contains description of device to control operation of heat center used in proposed method.

EFFECT: improved efficiency of control owing to maintaining constant summary flow rate of heat carrier in heating system at provision of designed (or when necessary, required) heat consumption of object and 20-30% reduction of consumption of high-temperature heat carrier.

3 cl, 2 dwg

Description

The invention relates to a power system, in particular to a heat supply, and can be used in open heat supply systems of residential, public and industrial buildings with a dependent scheme for connecting to a heating network, or for a boiler room with a group of consumers.

Water heating systems are connected to heating networks with mixing at heating points in the following cases:

1) with a pump on the jumper between the supply and return pipelines of the input - with insufficient available head for the elevator to work and pressure in the supply pipe exceeding the static pressure of this heating system by at least 5-10 meters of water column, but not dangerous to the strength of this system ;

2) with a pump on the supply pipe after a mixing jumper between the supply and return pipes - at a static pressure of the system equal to or higher than the pressure in the supply pipe of the heating network or, if necessary, increase the available pressure in the heating system;

3) with a pump on the return pipe from the heating system to the mixing jumper (along the return water) - at a pressure in the return pipe of the network exceeding the permissible limit for this heating system.

The pressure developed by the mixing pump should be 1-2 meters higher than the calculated pressure loss in the heating system (see M. Apartsev, Setting up water for district heating systems. M .: Energoatomizdat, 1983, p. 60).

In all these cases, the mixing pipeline should provide the least pressure loss to reduce power losses on the shaft of the mixing pump (mainly centrifugal type).

The known method and device according to patent No. 2239751. The method of regulating the operation mode of the water heating system, including the supply of network water to the heating system from the supply pipe, by shaking the coolant with a circulation pump, characterized in that the change in the flow ratio of the main and mixing coolant is carried out synchronously by balancing valves, keeping the total flow rate of the coolant constant. A device for regulating the mode of operation of a water heating system, comprising a circulation pump on the supply pipe after the mixing unit, characterized in that balancing valves are installed in front of the mixing unit and on the mixing pipeline, and also additionally on the return pipe; a check valve is installed in front of the balancing valve in the mixing pipe; a coolant purification filter is installed on the supply pipe.

The disadvantage of this method and device is the strict ratio of the costs of the network and the mixed coolant, determined synchronously by balancing valves, while maintaining the total flow rate constant. Reconfiguring balancing valves when changing operating modes of the heating system requires qualified personnel and the use of instrumental methods of tuning the regulation system. Since the circulation pump pumps the total flow rate of the coolant not only in the heating system, but also through the throttle devices (balancing valves), this significantly increases the installation and power consumption of the pump. The ingress of small mechanical impurities into the heating water from the heating system leads to wear of the seats in the valves, which requires repair and reconfiguration.

The technical problem, the solution of which the proposed solution is aimed at, is to increase efficiency without compromising the reliability of the system by regulating the flow of coolant.

The problem is solved in that the method of regulating the operation of the heat supply system includes the supply of network water to the heating system and hot water supply after the pump mixes the coolant from the return pipe.

The change in the ratio of the costs of the network and the mixed coolant is carried out by changing the pump speed, i.e. exceed the pressure of the mixed coolant over the conditionally constant pressure of the mains water, which corresponds to the characteristic of the heating network at the point of connection of the heat point (thermal substation).

The implementation of the proposed method and device provides an increase in the efficiency of controlling the heat load by maintaining the estimated heat consumption of the facility due to a significant (up to 30%) reduction in the consumption of high-temperature coolant exclusively by hydraulic means without the use of throttling devices.

In addition, the proposed method maintains the temperature of hot water in the water supply pipeline at the level of SNiP requirements in a wide range of regulation of the combined heat load of heating and hot water supply (almost until the average daily outdoor temperature is below -15 ° C) without additional control devices.

During the period of maximum water intake for household needs of the consumer, when the hot water consumption exceeds the water consumption for heating and there is a high probability that the available pressure will be reduced to an insufficient value necessary for the stable operation of the water-water elevator, the pump can ensure hydraulic stability of heating systems and hot water supply .

The use of electronic equipment in this circuit is not an obstacle to the implementation of this invention, since when it fails, the system returns to its original state without changing the hydraulic characteristics of the network. The selection of the pump, carried out according to the technical conditions for connecting the heat point (thermal substation) to the heating system, allows its use in manual operation mode. Manual operation is also provided for autonomous operation of the heat supply system in the event of an accident on the distribution (main) heating network.

New in the proposed method is that they change the flow ratios of the network and the mixed heat carrier by a pump with an adjustable speed, maintain the calculated circulation flow in the heating system constant, regardless of the load of hot water supply, maintain the estimated heat consumption of the object and the temperature of hot water close to the standard value the pipeline.

To implement this method, a mixing pipeline is mounted on the jumper between the supply and return pipelines to the water-elevator elevator and a moto-mixing pump equipped with an adjustable drive is installed; the mixing pipe is inserted into the return pipe at the inlet, and at the outlet into the supply pipe.

The mixing pipeline is equipped with a spring-loaded check valve to cut off the high-temperature zone of the network when the mixing pump stops.

New in the proposed method is that the selection of the coolant by the pump is carried out from the zone of minimum dynamic pressure of the return flow of network water, and the flow is carried out in the center of the flow of the supply pipe to the zone of maximum dynamic pressure (see Figure 2). This allows you to minimize the pressure loss in the mixing pipe and more efficiently use the pressure-flow characteristic of the pump without having a noticeable effect on the characteristic of the heating system.

Analysis of scientific, technical and patent information shows the lack of coincidence of the distinctive features of the claimed method and device with the signs of known technical solutions.

All known methods and devices for regulating the heat load using a pump at a heat point include control or balancing valves that perform flow throttling, which leads to a decrease in pump power and excessive energy consumption.

The proposed technical solutions have significant features that together affect the achieved result, namely, cost-effectiveness, availability of the purchase of silent pumps and frequency converters, quick payback (within one heating season) regulation method that performs a complete cycle of heat loss compensation through the barriers of a heated building when the outside temperature changes, without waiting for changes in the thermal regime of the heating system.

The proposed solution is presented in a schematic diagram (Figure 1). The device for regulating the operating mode of a heat point (thermal substation) contains a supply 1 and return 2 network water pipe, a water 3 and circulation 4 hot water system pipe, a mixing pipe 5 is installed between the supply and return pipes with a mixing pump 6 and a spring check valve 7 2. Two ball valves 8 are installed for dismantling the pump and check valve.

The heat point (thermal substation) is mainly equipped with flow rate converters for network water 10 at the supply and return pipelines, as well as with water meters 11 at the draw-in and circulation pipelines. At the outlet of the circulation pipeline, a check valve 9 is installed to exclude unregistered selection of the coolant and reliable indications of the consumed heat energy read by the heat meter of the commercial metering unit.

In addition, the heat station (thermal substation) in accordance with the standards is equipped with mechanical filters on the supply and return pipelines for reliable operation of the flow converters of the network water and pump, as well as thermometers and manometers to provide visual control over the parameters of the coolant.

The method of regulating the mode of operation of the heating system is as follows.

In the initial state, the water-water elevator of the heating system is configured to quench the excess pressure created by the network pumps of the heating system at the point of connection of the heat point (thermal substation), and to allow the estimated flow rate determined by the heating load to pass into the heating system.

The water-water elevator performs the function of a pressure regulator and provides a hydraulic mode of the heating system with a constant mixing ratio.

In open heat supply systems, the compensation for undersupply of heat is usually carried out by an increased temperature schedule, taking into account the possible change in the flow of the coolant into the heating system with an increase in the load of the hot water supply system

Due to the fact that at the beginning of the heating season the temperature of the supply water in the supply pipe for open heating systems is 70-75 ° С, the reduction of the high-temperature coolant will not lead to a decrease in the temperature of hot water in the water supply pipe below the sanitary norm (55-60 ° С ) even in manual operation of the pump. However, manual operation of the pump is associated with the need for qualified service personnel.

In automatic control mode, signals are received from the heat meter, temperature sensors of the network water in the supply pipe T1, network water in the return pipe T2, mixed water behind the elevator T3, hot water in the water pipe T4 and outdoor air T _n.v.

They regulate the speed of the stimulating mixing pump and maintain the hydraulic and thermal parameters of the coolant, which ensure the set value of heat consumption at the actual outdoor temperature.

The proposed solution in the most efficient way ensures that the load of hot water supply is satisfied without additional consumption of network water in comparison with the estimated water consumption for heating.

The auto-regulation system provides technological protection in case of deviation of any of the incoming signals by switching to the "standby" mode, i.e. the absence of supply of the mixed coolant, but at the same time, until the personnel intervenes, it saves at the inlet of the mixing pipeline a certain “hydraulic reserve” for the stable operation of the water-elevator elevator. Which, in turn, will ensure, regardless of the amount of water supplied from the heating system, a constant flow of circulating water in the heating system, ensures its correct distribution among the heating devices.

In the period of lack of water intake with the unused thermal energy coming from the hot water circulating system, the system will automatically use it in the heating system, avoiding the overconsumption of high-temperature coolant.

The use of a pump according to this scheme provides a wide range of regulation, since the water flow in the heating system is kept practically unchanged when the flow of mains water changes from calculated to zero.

The auto-regulation system will allow:

a) it is more efficient to use a high-temperature coolant and, due to this, get a real reduction in thermal energy consumption during “overflows” of main (distribution) networks;

b) maintain the necessary hydraulic mode of operation of heating systems and domestic hot water supply;

c) timely and smoothly adjust the coefficient of admixture at the heat input, taking into account the characteristics of the local system, the temperature of the outdoor air and the flow rate of the coolant for the needs of hot water supply;

d) ensure the standard value of the temperature of the network water returned to the return pipe of the heating main;

d) to effectively use the heat storage capacity of a heated building with sharp daily fluctuations in the temperature of the outside air;

f) significantly reduce the energy consumption for transportation (pumping) of the coolant.

In order to ensure the least pressure loss in the mixing pipeline, a device for implementing the control method is proposed (see Figure 2).

The use of this device is as follows. The adjustable drive of the booster pump maintains the rotational speed and provides the set value of heat consumption at the actual outdoor temperature. In this case, the water flow through the mixing pipeline will be variable, i.e. equal to the value corresponding to the discharge flow characteristic at the actual speed of the pump.

At low flow rates of the mixed coolant, the pressure created by the pump is directly dependent on the total pressure drop and its loss on the non-return valve, so a spring-type non-return valve is used, which gives a tangible effect here.

At maximum flow rates of the mixed coolant, the pressure created by the pump is directly dependent on the total pressure drop and its losses already in the mixing pipeline itself. Here, a tangible effect is achieved by the method in which the mixed heat carrier is taken from the flow with a minimum dynamic pressure in the return pipe and fed into the maximum dynamic pressure stream in the supply pipe.

The above information indicates that when using the claimed method and device the following set of conditions:

1) a tool embodying the claimed method and device is intended for use in industry in the field of heat power;

2) for the claimed method and device in the form described in the claims, the possibility of its implementation using the means and methods described in the application or known prior to the priority date is confirmed;

3) a heat supply system embodying the claimed invention, in its implementation is able to ensure the achievement of the desired technical result.

Therefore, the claimed invention meets the condition of "industrial applicability".

Claims (3)

1. The method of regulating the operating mode of a heating unit with an open heat supply system equipped with a water-water elevator and a commercial metering unit for heat energy, comprising supplying network water to the heating system and hot water supply by mixing the coolant from the return pipe through a forced-mix pump, characterized in that they change and regulate the ratio of the flow rates of the network and the mixed coolants by the centrifugal pump pump, exceed the pressure of the mixed coolant I am above the conditionally constant pressure of the network water in the supply pipe, while maintaining the estimated heat consumption of the object, while the mixed heat carrier is taken from the flow zone in the return pipe with the minimum dynamic pressure of the network water at the pipe wall and fed into the zone of maximum dynamic pressure of the network water in the supply piping to the center of the pipe. 2. The device for regulating the operating mode of the heat point used in the method according to claim 1, containing the supply and return pipelines of the hot water supply system with a mixing pipeline mounted between them, on which a centrifugal-type induction-mixing pump and a water-water elevator are installed in parallel operation, moreover, on the mixing pipeline, the pump is equipped with an adjustable drive, which changes the speed to effect mixing of the coolant. 3. The device according to claim 2, characterized in that a spring check valve is installed after the pump along the water.

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