KR101075893B1

KR101075893B1 - Heating energy supplying method in district heating system

Info

Publication number: KR101075893B1
Application number: KR1020090089981A
Authority: KR
Inventors: 조성환; 정상훈
Original assignee: 전주대학교 산학협력단
Priority date: 2009-09-23
Filing date: 2009-09-23
Publication date: 2011-10-25
Also published as: KR20110032474A

Abstract

The present invention relates to an energy supply method for efficiently supplying energy to district heating mainly used in a large apartment complex, etc., and setting a target indoor temperature desired for each household in the target building to calculate a target indoor temperature of the building. Step (S100); Calculating a heat load by a heat resistance-heat capacity method by reflecting the calculated target indoor temperature, outdoor temperature, and solar heat of the building (S200); The calculated heat load is input to a controller for controlling the opening degree of the supply valve of the district heating system to calculate the opening degree of the valve, and adjusting the opening degree of the valve in real time according to the calculated opening degree (S300). It is done.

According to the present invention, it is possible to control and supply an appropriate amount of hot water in a district heating system in real time, thereby achieving rationalization of energy use.

District heating, heat capacity, heat load, heat resistance

Description

Control method of heat energy supply of district heating system {HEATING ENERGY SUPPLYING METHOD IN DISTRICT HEATING SYSTEM}

The present invention relates to a heat energy supply control method for efficiently supplying heat energy from a district heating system to a large-scale residential complex or multi-family apartment, and more particularly, heating a building according to a change in outside temperature by using a heat resistance-heat capacity method. The present invention relates to a method for controlling the heat energy supply of a district heating system that can rationalize energy use by calculating a load and appropriately adjusting the amount of heat energy supplied from the district heating system according to the calculated heating load.

Conventionally, in the large-scale apartment complexes, a so-called central heating system has been adopted in which a central machine room is provided for each apartment complex, and a gas boiler is installed in the central machine room to supply hot water from each home. There is a problem of supplying more heat energy than necessary because it supplies heat energy in accordance with the target room temperature of the generation, and if the target room temperature is lowered to prevent this problem, the low-rise generation or the outermost generation in the winter is too low. There is a problem.

In order to solve the problems of the central heating system, an independent boiler such as a gas boiler is recently installed for each household, so that the amount of heating energy can be controlled by each household, thereby causing excessive energy consumption according to the central heating system. However, since each boiler needs to be installed for each household, there is an additional cost, and also expensive heating costs due to the use of expensive gas, and moreover in an apartment complex that supplies energy for heating by the existing central heating method. When switching to the independent heating method there is a problem that you can not use the equipment and piping, such as heat exchangers already installed at all.

Recently, as a way to rationalize the use of energy, a district heating system, which is a method of supplying heat for heating from one or several heat source devices in a building in a certain area, has been introduced. Electricity is generated and the water is heated to a high temperature by the remaining heat, so that the heated water is supplied to a machine room of a nearby apartment complex. The cogeneration district heating system, which is a method of heating water and supplying it to each household with heating water, is in the spotlight because of the low heating cost and the rational use of energy, which has been applied to the existing central heating machine room. Another advantage is that the installed heat exchanger or piping can be used as it is.

When the heat energy (hot water) is supplied from the cogeneration plant (district heating system), the method of supplying the heat energy for each generation in the apartment complex is described in more detail. As shown in FIG. The steam is heated by a primary heat exchanger installed in the power plant, and then condensed water is returned to the boiler. The hot water produced by heat exchange with steam is a secondary heat exchanger installed in a machine room of an adjacent apartment complex. The hot water introduced into the secondary heat exchanger is used to heat the water supplied to each generation through heat exchange to make it hot water, and then it is returned to the power plant. The hot water heated by the secondary heat exchange is transferred to a pump installed in the machine room. It is sent to each household and used for heating or hot water supply.

At this time, in front of the secondary heat exchanger, a flow control valve and a calorimeter for measuring and charging the total amount of thermal energy supplied to each complex are installed in order to adjust the flow rate of the hot water supplied from the district heating system (power plant).

On the other hand, each household in the apartment complex is equipped with a calorimeter to charge according to the energy used by each household, but this calorimeter is generally not connected to a central control panel installed in the machine room or management room. In order to charge according to the quantity, it is inconvenient to check the usage of each household one by one, and to solve this inconvenience, the calorimeter installed in each household must be connected to the central control panel. Since the wiring is required to rewire, the existing apartments still check the amount of usage for each household every month as in the prior art.

For this reason, cogeneration power plants that supply heat energy to district heating systems roughly estimate the required amount of heat energy in consideration of the outside temperature and the results of their use, and for this reason, rational use and efficient use of energy are hindered. If the outside temperature changes drastically, even if the amount of thermal energy is adjusted to reflect the change, it is also necessary to supply it depending on the driver's experience or historical data. Therefore, there is a significant difference between the actual amount of energy required and the amount of energy supplied. There can be.

The present invention has been made to improve the problems of the prior art as described above, the present invention in the district heating system implemented in apartments or large-scale residential complexes, etc., the heat energy actually required by a computer method to calculate the calculated The purpose of the present invention is to provide a heat energy supply method that can rationalize the use of energy by controlling the amount of heat energy supplied from the district heating system according to the amount of heat energy in real time.

In addition, the present invention is to provide a heat energy supply method that can be controlled in real time to compensate for the amount of heat energy supplied in accordance with the change in the outside temperature, and can supply heat energy close to the heating load actually required for heating of the building. There is another purpose.

The purpose of the present invention as described above is to calculate the heat load of the entire building by calculating the heat energy required for each generation according to the outside temperature by the heat resistance-heat capacity method, and then add it, and district heating system according to the calculated heat load of the building This is achieved by adjusting the opening degree of the flow regulating valve in real time.

Another object of the present invention is achieved by modifying the generational indoor target temperature applied to the heat resistance-heat capacity.

The present invention in the district heating system implemented in apartments or large residential complexes, by using the heat resistance-heat capacity method to calculate the heating load according to the change in the outside temperature by a computer method, thereby controlling the amount of heat energy supplied in real time By supplying it, it is possible to reflect environmental changes such as changes in solar heat caused by the operation of the sun, and at the same time, it is possible to adequately supply as much thermal energy as necessary, thereby achieving rationalization of thermal energy use.

In addition, the present invention can achieve the supply of heat energy close to the actual by making it easy to modify the heating load obtained by the heat resistance-heat capacity method is different from the actual heating load.

Hereinafter will be described in more detail with reference to the accompanying drawings showing an embodiment of the present invention.

The present invention relates to a thermal energy supply method for supplying the thermal energy required in a large residential complex or apartment complex rationally and efficiently, the present invention is largely calculated as the average room temperature of the building step (S100), heat It includes a load calculation step (S200), valve adjustment step (S300), calibration step (S500), failure diagnosis step (S500) and the like.

① Calculating the target room temperature of the building (S100)

Each household located in the target building (usually in the machine room installed in the apartment complex, each building or two buildings are bundled and managed to supply thermal energy, hereinafter referred to as "building" for convenience of explanation). The target room temperature may differ by month, area, location, and installation direction due to the effects of solar radiation.The desired room temperature by generation is the indoor room temperature when the indoor room temperature is large. May be somewhat higher than if small, and also if the installation location or direction of the north facing north may be somewhat higher than the desired room temperature. Accordingly, this step is a step of determining the target indoor temperature for each household according to the number of generations, the location and direction of the household.

At this time, the target room temperature may be determined based on the energy consumption used in each year by each household. However, in general, the indoor temperature of the apartment in winter is 21 ° C., which may be determined at an arbitrary value with a slight deviation.

When the desired target room temperature is determined for each generation by the above process, the target room temperature of the building can be obtained based on the following equation (1).

here,

Is the target room temperature of the building,

Is the number of households in the building,

The indoor area of each household,

Is the target room temperature for each household.

② Heat load calculation step (S200)

This step is to calculate the heat load to be supplied to each building to meet the target indoor temperature when the target indoor temperature of the building is determined by the above-mentioned building target room temperature calculation step (S100). In addition, the heat transfer amount and radiant heat are different depending on the structure and direction of the copper. Also, when heat energy is supplied to each household, the entire interior of the household must first be heated first. More calories are needed for the state.

Given these various environmental factors, it is not difficult to manually calculate and calculate the heat load required for each building.

Accordingly, as shown in FIG. 2, a thermal resistance-capacitance method for calculating energy required for a building by expressing it in the form of an electric circuit according to the structure, direction, and location of a building has been developed. This method expresses the wall or floor of each building with a heat resistance and at the same time heat capacity, thereby calculating the energy required for the building, that is, heating load or cooling load. It has recently attracted attention as a method of calculating the heat load of a building.

In more detail, the heat resistance-heat capacity method is described, in which one wall is not only a heat transfer medium but also a heat storage medium, and when windows are installed on the wall, the heat transfer rate through the window and the heat transfer rate through the wall are different. One wall may be converted into two heat resistances and one heat capacity connected in parallel as shown in FIG. 3.

In addition, a building such as an apartment may have a rectangular parallelepiped shape, but may have a polygonal column shape, and the most influential effect on the heating load or the cooling load is solar heat radiation, which is reflected by the operation of the sun. As shown in FIG. 3, the standard building (east) to be applied is one standard having vertical walls, ceilings, and floors in eight directions of east, west, south, north, northeast, southeast, northwest, and northwest. After converting into a building model, these vertical walls, ceilings, and floors are converted into heat storage and heat capacity, and these heat resistances and heat capacity are connected to each other, and given appropriate values according to the structure, direction, and position of the wall. Calculate the heat load required by the building.

On the other hand, the electric circuit having a resistance and capacitance is expressed as the following equation (2), that is, the amount of charge charged in the capacitance per unit time is expressed as the difference of the current.

here,

Is the capacitance,

Is the potential difference,

Is the input current,

Is the output current,

Is resistance.

Similarly, in a thermal system, energy accumulated in a building per unit time is the same as input energy-output energy or input heat-output heat, which can be expressed as Equation 3 below.

here,

Is the total mass of the building,

The specific heat of the building,

Is the outside temperature,

Is the internal temperature of the building,

Is the heat obtained by the lights or solar heat inside the building,

Is heat resistance.

It is clear from Equation 3 that there is a similarity between the equation of the thermal system and the equation of the electrical circuit. In other words,

Is

And

Because both describe the physical characteristics of the system,

Same as, temperature

And potential difference

Are similar because they all show differences in potential energy,

Is

In the end, both systems are the same system.

Equation 3 is a heat balance equation, and when the equation is applied to each building wall or ceiling, it can be expressed as Equation 4 below.

here,

Specific heat such as building walls, ceilings,

Silver time

Temperature of the wall,

Silver time

Temperature of the wall,

Is the time interval,

Time

Location of wall in

Temperature at,

Time

Location of wall in

Temperature at,

Silver wall

Thermal resistance at position,

Is the heat obtained by the light inside the building or solar heat.

If you do not supply heat in the building during winter, the room temperature will gradually decrease. Therefore, in order to maintain the room temperature above a certain temperature, heat energy must be supplied to the building, which is a heat load. Since heat is generated from many heating elements such as products, lamps, and gas stoves, and heat is obtained by solar heat, the heat amount obtained from these heating elements and the solar irradiation are calculated to calculate the heat load actually supplied. The heat should be calculated in consideration of all the heat, but since the heat obtained from the heating element in the room is extremely weak compared to the heat obtained by the irradiation of the sun, the present invention considers only the heat acquired by the irradiation of the sun to simplify the calculation.

On the other hand, the amount of heat obtained from each wall by the irradiation of the sun is different for each day, time, direction, but generally the amount of heat obtained by the irradiation of the sun can be obtained from the following equation (5).

here

Full solar heat irradiated to the wall,

Is the direct sunlight from the sun,

Is solar heat that diffuses from the atmosphere,

Is solar heat reflected from the ground to the wall,

Is the angle of incidence of the building in sunlight.

Solar heat by direct irradiation on the wall of the sun (

There are several solar models to calculate), but the commonly used model is a model proposed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (ASHRAE). Solar

Is shown in Equation 6 below.

here,

Is the sun's direct radiation from the sun,

Seemingly solar,

Is the atmospheric extinction coefficient,

Is the altitude angle of the sun.

Also diffuse solar heat

Again according to the ASHRAE model is obtained by the following equation (7).

Where C is a constant, 0.135 in summer and 0.058 in winter, obtained by interpolation according to date,

Is the sun's direct radiation from the sun,

Is the shape factor of the wall and is equal to the part of the diffuse solar heat incident on the surface of the wall.

Also, solar heat reflected from the ground to the wall

Is calculated by the following equation (8).

here,

Is solar heat reflected from the ground to the wall,

Is the sun's direct radiation from the sun,

Is the heat of the sun,

Is the reflectivity of the ground,

Is the shape factor of the ground.

When the solar heat obtained from each wall is obtained by the above process, all of them are summed to obtain the solar heat obtained for the entire building, and then supplied to Equation 4 when supplied to Equation (4). The heat load is calculated. At this time, if the required heat load is obtained at each time while changing the target indoor temperature, outdoor temperature and solar heat, a heat load curve as shown in FIG. 4 is obtained.

③ Valve control step (S300)

When the heat load is calculated in the heat load calculation step (S200), when the heat load is input to a controller that controls the opening degree of the district heating supply valve which is located in the machine room and supplies hot water to the building, the valve controller sends the input heating load. By calculating the required valve opening degree as a reference, the opening degree of the valve is adjusted to regulate the flow rate of the hot water supplied to the building, whereby the amount of hot water supplied to the building is appropriately supplied without being oversized.

At this time, while continuously monitoring the change in the outside temperature, recalculating the necessary heat load according to the change of the outside temperature to adjust the opening degree of the valve, it is possible to control the amount of hot water for heating in real time according to the heat load, thereby resulting in district heating By properly controlling the amount of energy supplied by the system in real time, energy savings can be achieved while at the same time enabling the occupants in the building to live comfortably.

④ Calibration step (S400)

Although the heat load obtained in the above-described heat load calculation step (S200), the environmental factors are properly reflected because the matters related to the installation direction, structure, and material of the actual building act as input elements, the heat load obtained above is ultimately ultimately Since theoretically obtained, it may be different from the heat load actually required for heating of the building. Accordingly, the present invention includes a calibration step to correct these differences so as to be closer to the actual.

For this purpose, the calorimeter installed for each generation in the building is investigated, and the actual target room temperature for each household is inverted from them, and the obtained target room temperature is applied to the heat resistance-heat capacity method. If you change the target room temperature for each generation and modify it, you can get closer to the real one. If you repeat this process, you can get closer to the real one.

As another calibration method, the heating fee used by each household is charged according to the amount of heat used for each month for each household. Since the target room temperature can be known and the weather agency can know the daily and hourly outside temperature of the region for the last month, the hourly outside temperature and the average indoor temperature by generation are used as reference input data at the same time of next year. By calculating the load, the actual heat load can be calculated. By adjusting the valve opening, more precise and accurate amount of energy can be supplied, thus saving the supply energy. Close control allows for significant energy savings Will be.

⑤ System fault diagnosis step (S500)

On the other hand, if the calorie graph supplied for the day from the district heating calorimeter installed in the machine room is corrected according to the outside temperature of the previous day, and compared with the calorie graph supplied for the day before, both graphs are normal. The same tendency will be shown within a certain range, and accordingly, in the present invention, if the difference is more than a predetermined width, it may be determined that there is an abnormality in the system, and thus the entire system may be checked again.

1 is a flow chart showing an example of a real-time control method of district heating according to the present invention,

2 is a circuit diagram showing an equivalent heat resistance-heat capacity model of a wall;

3 is a perspective view showing one room equivalent model,

4 is a graph showing an example of a heat load curve according to the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

10: wall 11: window

Claims

Calculating a target indoor temperature of each building in the target building by setting a desired indoor target temperature (S100);

Calculating a heat load by a heat resistance-heat capacity method by reflecting the calculated target indoor temperature, outdoor temperature, and solar heat of the building (S200);

The calculated heat load is input to a controller for controlling the opening degree of the supply valve of the district heating system, and the opening degree of the valve is calculated and the opening degree of the valve is adjusted in real time according to the calculated opening degree (S300).

In the step of calculating the heat load (S200), the calorimeter installed for each generation in the building is examined for calories used for one day in each generation, and the actual target indoor temperature for each generation is inverted therefrom, and the target for each generation is calculated. And a correction step (S400) of correcting the indoor target temperature for each generation applied to the heat resistance-heat capacity so as to be the indoor temperature (S400).

delete

The method according to claim 1,

The thermal energy supply control method of the district heating system includes a system fault diagnosis step (S500), wherein the system fault diagnosis step (S500) is to modify the calorie graph supplied for a day from the district heating calorimeter according to the previous day's outside temperature. The heat energy supply control method of the district heating system, characterized in that it is determined by the result of comparing with the calorie graph supplied for the day before.