CN101158485A - A Method for Realizing Hydraulic Uniformity in On-Off Adjustment Mode of Central Heating System - Google Patents

Abstract

The invention relates to a method for realizing hydraulic uniformity in an on-off adjustment mode of a central heating system, belonging to the field of heating, ventilation and air conditioning. The hydraulic uniformity method is based on a certain parameter and fixedly staggers the initial moment of the on-off control valve of each user's heat inlet according to a certain method, so that the users who open and close the entire heating system in time and space are evenly distributed, realizing the system The hydraulic conditions are uniform and stable. Compared with the traditional on-off control method, which relies on the random cumulative effect of a certain number of users to achieve hydraulic uniformity passively, the method provided by the present invention belongs to the active control valve action, which makes the hydraulic uniformity of users, and there is no requirement on the number of users , not only makes the number of on-off control heating system valve switch users evenly distributed in time, but also in space, so that the overall hydraulic working condition is stable.

Description

A Method for Realizing Hydraulic Uniformity in On-Off Adjustment Mode of Central Heating System

technical field

The invention relates to a method for realizing hydraulic uniformity in an on-off adjustment mode of a central heating system, belonging to the field of heating, ventilation and air conditioning.

Background technique

At present, the central heating or air conditioning system with on-off adjustment is controlled by setting a deviation range centered on the indoor set temperature, and controlling the valve on and off according to the set deviation range, that is, when the room temperature is higher than the "set temperature + The valve is closed (opened) when the room temperature is lower than the "set temperature - deviation value", and the valve is opened (closed) when the room temperature is lower than the "set temperature - deviation value". The fan coil air conditioning system with on-off control is a typical example. Since the load of each user changes randomly, the control valves are also opened and stopped randomly. However, due to the large number, this random result shows that the total flow of the pipeline network will not change drastically within a certain period. tends to be more stable. Although this deviation control method can make the on-off control system run stably to a certain extent, the change of hydraulic conditions of the whole system is passive to adapt to the random adjustment of the end user. At the same time, the accuracy of room temperature control is low, and the valve is prone to frequent actions. Engineering applications have limitations.

The patent (Application No. 200610114686.2) discloses a method for realizing heat regulation and heat metering at the same time. The valve control method is based on the difference between the user's current set temperature and the actual temperature, and calculates the next period according to an algorithm (such as 30 Minutes) the valve opening duty ratio (the ratio of the valve opening time to the control cycle), and then control the opening and closing of the valve in the next cycle according to the duty ratio. This method is different from the above-mentioned room temperature deviation control method, although the user load is still It changes randomly, but the randomly changing load is only reflected in the difference in the duty cycle of each user valve. In actual operation, since the opening time of all user valves is concentrated in the first half of a cycle, the closing time of all user valves is concentrated. In the second half, this greatly increases the probability of valve action consistency. As long as the starting time of the valve action of each user is the same or the difference is an integer multiple of the period, and the duty cycle of each user is not 1, there will definitely be When all valves are closed at the same time, hydraulic power will become unstable. As shown in Figure 1, riser 1 has six users, when the control period is 30 minutes, and the valve duty cycle of each user is 0.5, if the starting time of the valve action is the same, the first 15 users in the next cycle Within 1 minute (30 minutes × 0.5), the valves of 6 users are opened at the same time, and the valves will be closed at the same time in the next 15 minutes (as shown in Figure 2). After 1 minute, all user valves are opened, and in the next 15 minutes, all user valves are closed, and the hydraulic condition is seriously deteriorated. During the first 3 minutes of the next cycle, all valves will be open, and for the next 12 minutes, all valves will be closed. Therefore, if this method of calculating the duty ratio to control the valve does not take a certain method to actively adjust the distribution of the working state of the valve, the hydraulic condition will be very unstable.

However, the above-mentioned problems can be solved by a method for realizing hydraulic uniformity in the central heating on-off adjustment mode provided by the present invention.

Contents of the invention

The object of the present invention is to provide a method for realizing hydraulic uniformity in the central heating (system) on-off adjustment mode.

Its basic principle is:

(1) According to a certain parameter and according to a certain method, the starting time of each user's hot inlet on-off control valve is fixedly staggered, so that the opening time and closing time of each user's valve are staggered from each other, and the user's hydraulic power is guaranteed to be uniform in time, as shown in the figure As shown in 3, the bottom of the time axis t represents the total flow rate of standpipe 1. When the control cycles of each user are staggered, only the valves of three users are fully open at any time, which avoids the riser caused by the non-staggered cycle in Figure 2. In the first half of each cycle, all 6 users are open and all 6 users are closed in the second half of each cycle.

(2) In order to ensure the uniformity of space and the convenience of operation, the standpipe is used as the basis for implementation, that is, only the staggering of users on the same standpipe can be considered, and the starting time between different standpipes can be consistent, so that the closing Users and open users are evenly distributed in space.

(3) In the central heating on-off control system disclosed in the patent (application number 200610114686.2), the on-off control valve of the heat inlet of each household has a unique address, which is used to pair with the room temperature controller. The algorithm staggers the starting time of each user's hot inlet valve. When installing for the first time, set the address of each user's on-off control valve according to "high address + low address". The "high address" is used to identify the building number and unit number, the "low address" is used to stagger the control cycle of the on-off valve, and the "high address + low address" is used for pairing communication between the on-off control valve and the room temperature controller.

(4) In order to achieve the purpose of staggering the control cycle, while assigning the low-order address, set the time reference for each on-off control valve, that is, "comparison table". Ensure that the time based on each user's staggering is consistent, and then according to this time, combined with the address, follow a certain algorithm to ensure that the starting time of each user's valve is staggered.

By the method of the present invention, the following objectives can be achieved:

(1) Solve the problem of hydraulic uniformity in the application of a method that simultaneously realizes heat regulation and heat metering disclosed in the patent (application number 200610114686.2), avoiding drastic changes in flow rate and causing deterioration of hydraulic conditions;

(2) Compared with the traditional on-off control method, which relies on the random cumulative effect of a certain number of users to passively realize hydraulic uniformity, the method provided by the present invention belongs to the action of actively controlling the valve, so that the hydraulic uniformity of users can be achieved in the number of users. There is no requirement on

(3) The method provided by the present invention not only makes the number of on-off control heating system valve switch users evenly distributed in time, but also in space, so that the overall hydraulic working condition is stable.

Description of drawings

Figure 1 is a schematic diagram of the installation of the on-off control device. Among them: 1- room temperature on-off control valve.

Fig. 2 Schematic diagram of hydraulic working conditions in the duty cycle on-off adjustment mode of the central heating system, in which: the shaded part represents the valve opening, the blank part represents the valve closing, and T represents a control cycle.

Figure 3 is a schematic diagram of the hydraulic working conditions of the central heating system under the on-off adjustment mode of the duty ratio after staggering each user's control cycle, where: the shaded part represents the valve opening, the blank part represents the valve closing, and T represents a control cycle.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the technical scheme of the present invention is described further:

Referring to Figure 1, there are 3 risers in a certain building, 6 users on each riser, and a room temperature on-off control valve is installed at the heat inlet of each user. The on-off of the valve is based on the difference between the set temperature and the actual temperature of each user, and calculates the duty ratio of the valve in a single cycle (within 30 minutes) according to a certain algorithm, and then controls the on-off of the valve according to the duty ratio. During installation, the on-off control valves of each user are set according to "high address + low address". The room temperature on-off valve of the hot inlet is based on the same time. The high-order address is used to identify the building number and unit number, and the low-order address is used to stagger the control cycle of the on-off valve. For example, the user 2-1 address is set as 2-1, the high address is 2, and the low address is 1. In order to make the hydraulic power of the whole system uniform, the 6 users in standpipe 1 are respectively set to 1, 2, 3, 4, 5, 6 according to the low address, and the start time of the room temperature on-off valve of each user is postponed for 5 minutes in turn, that is, if Taking the starting time of the valve action of user 1-1 as a reference, user 1-2 starts after a 5-minute delay, user 1-3 delays for 10 minutes, and so on, and users 1-6 start after 25 minutes. When the duty cycle of the user is 0.5, as shown in Figure 3, the shaded part represents the opening of the user's valve, and the blank part represents the closing of the user's valve. At any time in the standpipe 1, only three user's valves are open. The valves of the other three users are closed. If the other two standpipes adopt a similar method, only half of the user valves of the entire heating system are open at any time, and the other half of the user valves are closed, and the spatial distribution is relatively uniform, so that the hydraulic conditions of the entire heating system are uniform.

Claims (3)

1. A method for realizing hydraulic uniformity under the centralized heating on-off regulation mode, characterized in that: the hydraulic uniformity method is to fix and stagger the start of the on-off control valves of each user's heat inlet according to a certain method according to a certain parameter Time, so that the entire heating system is evenly distributed in time and space, and the users who turn on and off are evenly distributed, and the hydraulic working conditions of the system are uniform and stable. 2. The method according to claim 1, wherein the basis for staggering the start time of the on-off control valves of each user's hot inlet is that the on-off control valve of each user's hot inlet has a unique address. 3. The method according to claim 1, characterized in that: the method is to install a room temperature on-off control valve at the hot inlet of each user, and the on-off of the valve is based on the difference between the set temperature and the actual temperature of each user. Poor, calculate the duty ratio of the valve in a single cycle according to a certain algorithm, and control the on-off of the valve according to the duty ratio; when it is first installed, the on-off control valve for each user is based on "high address + low address" At the same time, it is necessary to set a time reference for each room temperature on-off valve, that is, "comparison table", so that the room temperature on-off valve of each user's hot inlet is based on the same time; the high address is used To identify the building number and unit number, the low address is used to stagger the control cycle of the on-off valve.

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