Existing building low-temperature hot water floor radiant heating thermodynamic balance control method

Abstract

The invention discloses a thermal balance control method for low-temperature hot water floor radiant heating of an existing building. The method comprises the following steps that the thermal load in each room is calculated; calculating the heat dissipation average temperature and heat dissipation capacity of the coil pipe in each room; the water inlet temperature of heating of the whole building is determined; the water inlet temperature, the water outlet temperature and the circulating flow of each coil pipe corresponding to each household water collector are calculated; calculating the circulation resistance of each coil pipe; and by taking the maximum circulating resistance value of the coil pipe of each household as a reference, a coil pipe flow pressure regulating joint is arranged between the adapter joint and the water segregator corresponding to each other coil pipe so as to regulate the circulating resistance of each coil pipe to be the maximum circulating resistance. By adding the flow pressure regulating section in the existing building low-temperature hot water floor radiant heating system, the hydraulic balance of the system can reach an ideal design state, the indoor temperature imbalance phenomenon of the existing building low-temperature hot water floor radiant heating system can be solved, and the indoor imbalance temperature difference of the building is reduced; and the condition of low-temperature-difference large-flow operation is changed.

Description

Technical Field

[0001] The invention relates to the technical field of indoor heating systems, and more particularly to a thermal balance control method for low-temperature hot water floor radiation heating of an existing building. Background Art

[0002] At present, the most commonly used indoor heating method for civil buildings is low-temperature hot water floor radiation heating (floor heating). This heating method is to introduce hot water with a temperature not higher than 60°C from the outdoor heating main pipe, distribute it to the distribution and collection tanks of each heat-using unit in the building through branch pipes, and then the distribution and collection tanks of each heat-using unit distribute the hot water to the various branch coil systems buried under the floor for circulation, heating the floor, and evenly radiating heat to the room through the ground. For residential buildings, each house is a heat-using unit, and a distribution and collection tank is designed and installed in each house; for non-residential buildings, the heat-using unit is the entire area served by each distribution and collection tank on the heating riser in the building.

[0003] Low-temperature hot water floor radiant heating has incomparable advantages over traditional heating and is a new and advanced heating method. It is comfortable, hygienic, environmentally friendly, beautiful, does not occupy the usable area, has thermal insulation, good thermal stability, uniform heating temperature, high efficiency, energy saving, and low operating costs, and has broad development prospects.

[0004] The current low-temperature hot water floor radiant heating has the phenomenon of uneven indoor heating temperature in actual operation. The heating temperature of the rooms on the ground floor and top floor of the same building is lower than that of the middle floors. In the houses on the same floor, the temperature of the rooms against the gable is lower than that of other rooms in the middle.

[0005] The main reason for the above-mentioned uneven indoor heating temperature phenomenon is the hydraulic imbalance in the current design. First of all, in the current design, the laying of floor heating radiator coils is based on the full area of ​​the room. As a result, rooms with large areas, such as the living room, are relatively hot, while rooms with small areas, such as the north bedroom, are not very hot. Secondly, the lengths of the branch coils carried by the same distribution and collection device are different, and there is no controllable measure for the hot water flow rate supplied by the distribution and collection device to each branch coil. Theoretically, the long coil serves a large area, and more hot water flows through the coil; the short coil serves a small area, and less hot water flows through the coil. However, in actual heating operation, the fluidity of water follows the principle of least resistance. Where the resistance is small, more water goes there. The longer the radiator coil, the greater the circulation resistance, and the circulation The less the circulating water volume; the shorter the heat dissipation coil, the smaller the circulation resistance, and the more circulating water volume, which is another problem that causes uneven room temperature; the third is that the number of coil branches of the distributor and collector in the current design is determined according to the number of main rooms so as to be able to control the switching function of the coils in each main room respectively, and one loop is laid for one main room, resulting in an imbalance rate of about 30%-50% in the circulation resistance of the several coils carried by the same distributor and collector; the fourth is that there is no effective control measure for the amount of hot water supplied from the unit riser to the distributor and collector of each household in the unit. All of them are manually debugged many times with stop valves, and it is difficult to achieve the ideal effect. At the same time, the hot water supplied by the unit riser to the distributor and collector of each household in the unit due to the gravity circulation natural additional pressure generated by the temperature drop of the hot water aggravates the vertical imbalance of the room temperature.

[0006] The above reasons are the reasons that cause the room temperature in the middle room to be too hot while the temperature in the rooms on the side, top floor and bottom floor is too low. In order to solve this problem, the heating unit generally adopts the operation mode of small temperature difference and large flow, and the temperature difference of circulating water is only about 5℃, but this operation mode has not been able to eliminate the imbalance of indoor temperature in the building. Based on this situation, in order to ensure that the room temperature of the rooms on the side, top floor and bottom floor reaches the national standard of 16℃ or above, the room temperature of the middle room is as high as 25℃ or above, and the middle room usually has windows open for heat dissipation.

[0007] Therefore, how to provide a control method that can improve the room temperature imbalance of existing low-temperature hot water floor radiant heating buildings, eliminate the occurrence of heat dissipation by opening windows in the middle rooms, and eliminate the operating mode of small temperature difference and large flow is an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0008] In view of this, the present invention provides a thermal balance control method for low-temperature hot water floor radiant heating of an existing building. For the already laid floor heating coils, according to the laying status of the room where they are located and the actual heat load of the room, pressure regulating orifice plates with different apertures are used to control the hot water circulation flow of each coil to achieve thermal balance in each room. At the same time, when distributing the flow of the unit riser, pressure regulating orifice plates with different apertures are also used to control the hot water flow entering each household to solve the problem of uneven indoor heating temperature in the entire building.

[0009] In order to achieve the above object, the present invention adopts the following technical solution:

[0010] A method for controlling thermal balance of low-temperature hot water floor radiation heating in an existing building, comprising the following steps:

[0011] S1. Calculate the heat load in each room;

[0012] S2. Calculate the average temperature and heat dissipation of the coil in each room;

[0013] S3, determine the water inlet temperature for heating the entire building;

[0014] S4. Calculate the inlet and outlet water temperatures and circulation flow rates of each coil corresponding to each household's water collector;

[0015] S5. Calculate the circulation resistance of each coil;

[0016] S6. Based on the maximum circulation resistance value of the coil corresponding to each household's distribution and collection device, install a coil flow pressure regulating joint between the adapter joint and the water distributor corresponding to each remaining coil to adjust the circulation resistance of each coil to the maximum circulation resistance.

[0017] The beneficial effect of the technical solution of the present invention is that by installing a flow pressure regulating section on each coil corresponding to the distribution and collection devices of each household, the circulation resistance of each coil can be adjusted, and then the hot water flow in each coil can be adjusted, so that the hot water flow in each coil reaches the design value, thereby achieving thermal balance in the room served by each coil.

[0018] Preferably, in step S1, the heat load of each room in the building is calculated according to the specifications and the building envelope.

[0019] Preferably, in step S2, the average temperature of the coil heat dissipation in each room is calculated according to the area of ​​each room, the heat load, and the laying spacing and area of ​​the coils, and then the heat dissipation of each coil in each household is deduced.

[0020] Preferably, in step S3, the water inlet temperature for heating the entire building is calculated based on the average heat dissipation temperature of the coil calculated in step S2 and the highest average heat dissipation temperature.

[0021] Preferably, in step S4, the outlet water temperature and circulation flow rate of the coil are calculated according to the total heat load of the room corresponding to each coil and the average heat dissipation temperature of the coil, and the inlet water temperature of the heating of the whole building in step S3, and then the outlet water temperature and circulation flow rate of each coil corresponding to each household and manifold are determined.

[0022] Preferably, in step S4, the total heat dissipation, total circulation flow rate and the inlet and outlet water temperatures of the manifold and collector are calculated for each household based on the inlet and outlet water temperatures and circulation flow rate of each coil.

[0023] Preferably, in step S5, the circulation resistance of each household's water inlet and outlet pipes and each coil is calculated according to the length of each household's water inlet and outlet pipes, the length of each coil and the circulation flow of each coil, and the total circulation resistance of each household is calculated at the same time.

[0024] Preferably, in step S6, a coil pressure regulating orifice is fixed in the coil flow pressure regulating node, and the circulation resistance value of each coil is adjusted to be equal to the maximum circulation resistance by adjusting the aperture of the coil pressure regulating orifice on different branches.

[0025] Preferably, the method further includes step S7: threading an inlet flow pressure regulating node between the unit riser and each household's inlet connecting pipe to make the total circulation resistance between each household equal.

[0026] Preferably, in step S7, a household flow pressure regulating orifice is fixed in the household flow pressure regulating section, and the aperture of the household flow pressure regulating orifice is adjusted to make the total circulation resistance between each household equal, while ensuring that the circulation flow into each household reaches the design value.

[0027] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a method for controlling the thermal balance of low-temperature hot water floor radiation heating in an existing building. By adding a flow pressure regulating section to the low-temperature hot water floor radiation heating system in an existing building, the hydraulic balance of the system can reach the ideal design state, and the indoor temperature imbalance phenomenon of the existing low-temperature hot water floor radiation heating building can be solved, the indoor temperature difference of the building can be reduced, and the low temperature difference and large flow operation situation can be changed;

[0028] The application of this method can control the indoor temperature difference within the standard specified 20 ± 2 ℃; can control the operating temperature difference of the low-temperature hot water floor radiant heating system to about 10 ℃ or more specified in the standard, so that the circulation flow of the system can be reduced, and a small flow, low head circulating water pump can be used instead, reducing the electricity expenditure of the circulating water pump, which can achieve obvious social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0030] Figure 1 The thermal balance control flow chart of low-temperature hot water floor radiant heating for existing buildings provided by the present invention;

[0031] Figure 2 A front view of the pressure regulating joint provided by the present invention;

[0032] Figure 3 A cross-sectional view of the pressure regulating section provided by the present invention.

[0033] in,

[0034] 1-pressure regulating joint; 2-pressure regulating orifice plate; 3-rubber pad; 4-external thread; 5-internal thread. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The embodiment of the present invention discloses a method for controlling thermal balance of low-temperature hot water floor radiation heating in an existing building. Under the premise of the existing pipe layout of the low-temperature hot water floor radiation in the existing building, the water inlet flow of each coil corresponding to the distribution and collection device of each household is reasonably controlled so that the thermal power of each room of each household tends to be balanced. At the same time, a regulating device for distributing the flow of the unit riser to the indoor system is added to regulate the flow of hot water delivered by the unit riser to each household.

[0037] This embodiment takes a six-story building corresponding to the severe cold zone C as an example. The building has a floor height of 2.9 meters and a basement floor height of 2.2 meters. The outer door of the stairwell is a 1.2m x 2.1m insulated double door; the unit entrance door is a 1.0m x 2.1m insulated anti-theft door, and the length of the entrance door gap is 6.2 meters; the living room exterior window size is 2.4m x 1.5m, and the window gap length is 6.0 meters; the bedroom exterior window size is 1.5m x 1.5m, and the window gap length is 3.0 meters; the kitchen exterior window size is 1.5m x 1.5m, and the window gap length is 3.0 meters; the bathroom exterior window size is 1.0m x 1.5m, and the window gap length is 3.0 meters. The thermal parameters of the external envelope structure are shown in Table 1:

[0038] Table 1 Thermal parameters of building envelope (severely cold C zone)

[0039]

[0040] When performing thermal balance control of low-temperature hot water floor radiant heating, follow the steps below:

[0041] S1. Calculate the heat load in each room;

[0042] Calculate the heat load for each room in the building according to code and building envelope;

[0043] When calculating the heat load, the heat transfer coefficient of the external envelope structure is calculated according to the limit value specified in the specification. In this embodiment, the heat loads of the corresponding rooms above and below the middle floors (second to fifth floors) are the same.

[0044] S2. Calculate the average temperature of the coil heat dissipation in each room according to the area, heat load, and the laying spacing and area of ​​the coils, and then deduce the heat dissipation of each coil in each household;

[0045] Check the coil layout diagram during construction, and accurately calculate the length of each coil in each household based on the actual pipe layout, and calculate the area of ​​the room heated by each coil, the length of the coil laid, the spacing between the coils, and the number of 90° elbows in the coil. The order of coil numbering is that the water distributor near the north wall of the bathroom is the first circuit, and the reverse direction is the second circuit, the third circuit, and the nth circuit;

[0046] The average water supply temperature of the floor heating coil in the room is calculated based on the heat load value of each room, the area of ​​the coil laid in each room, the spacing between the coils laid, and other basic conditions;

[0047] The average temperature of the coil heat dissipation in the room should be determined by taking into account the influence of the floor furniture covering and other factors. When determining the average temperature of the coil heat dissipation in the living room and dining room, the heat dissipated by the connecting coils to other rooms through the living room or dining room floor should be excluded;

[0048] In this embodiment, the coil uses a PE-X pipe with a thermal conductivity of 0.38W / (m·K), and the floor is a ceramic surface layer. The influence of furniture shielding in the room is considered in the calculation. The bedroom takes a correction coefficient of 1.30, the living room takes a correction coefficient of 1.10, and other rooms do not consider the influence of furniture shielding. According to JGJ142-2012 Technical Specification for Radiant Heating and Cooling, the results are shown in Table 2, which shows the average heat dissipation temperature of the existing coils in the rooms on the first, second and sixth floors in this embodiment. The average heat dissipation temperature of the existing coils in the rooms on the third, fourth and fifth floors is the same as that of the rooms on the second floor (in actual projects, the actual laying conditions of the coils in each room must be clearly surveyed and calculated for different conditions).

[0049] Table 2 Calculation table of average temperature of coil heat dissipation

[0050]

[0051]

[0052] Calculate the heat dissipation of each coil in each household based on the average heat dissipation temperature of the coil:

[0053] Taking the third-line coil of the left household on the first floor as an example, the third-line coil provides heating to the south bedroom 2 of the household. The coil comes out of the bathroom and enters the south bedroom 2 through the dining room floor. The south bedroom 2 is the main room served by the coil. The average water supply temperature is 38.41℃, which is the average water supply temperature of the third-line coil.

[0054] First, calculate the heat dissipated by the third coil passing through the bathroom floor. The indoor heating temperature of the bathroom is 16°C, and the area of ​​the third coil passing through the bathroom floor is 0.48m 2 The coil spacing is 75mm, and the calculation is based on a spacing of 100mm. According to the JGJ142-2012 Technical Specification for Radiant Heating and Cooling (Table B.1.1-1 Heat Dissipation per Unit Floor Area of ​​Cement, Stone or Ceramic Surface Layers), the unit heat supply of the third coil in the bathroom is 120.58W / m 2 , to obtain

[0055] Heat dissipation of the third coil in the bathroom = bathroom floor area 0.48m 2 The unit heating capacity of the third coil in the bathroom is 120.58W / m 2 =58W:

[0056] Secondly, calculate the heat dissipated by the third coil passing through the restaurant floor. The indoor heating temperature of the restaurant is 18℃, and the area of ​​the third coil passing through the restaurant floor is 3.08m 2The coil spacing is 230mm, and the calculation is based on a spacing of 250mm. According to the JGJ142-2012 Technical Specification for Radiant Heating and Cooling (Table B.1.1-1 Heat Dissipation per Unit Floor Area of ​​Cement, Stone or Ceramic Surface Layers), the unit heat supply of the third coil in the restaurant is 94.21W / m 2 , to obtain

[0057] Heat dissipation of the third coil in the restaurant = restaurant floor area 3.08m 2 The unit heat supply of the third coil in the restaurant is 94.21W / m 2 =290W;

[0058] Calculate the heat dissipated by the third coil on the floor of South Bedroom 2 again. The indoor heating temperature of South Bedroom 2 is 20℃, and the area of ​​the third coil on the floor of South Bedroom 2 is 12.52m 2 Considering the effect of furniture blocking the bedroom, the area correction should be made. The correction coefficient is 1.3. The corrected effective heating area is 12.52 / 1.3=9.63m 2 The coil spacing is 200mm. According to the JGJ142-2012 Technical Specification for Radiant Heating and Cooling (Table B.1.1-1 Heat Dissipation per Unit Floor Area of ​​Cement, Stone or Ceramic Surface), the unit heat supply of the third coil in the south bedroom is 89.71W / m 2 , to obtain

[0059] Heat dissipation of the third coil in the south bedroom = effective floor area of ​​the south bedroom 9.63m 2 The heating capacity of the third coil in the south bedroom is 89.71W / m 2 =864W;

[0060] The sum of the above three items is 1212W, which is the heat dissipation of the third coil of the left household on the first floor. According to the above method, calculate the heat dissipation of each coil of each household on the remaining floors.

[0061] Table 3 Statistics of heat dissipation of coils (left household)

[0062]

[0063]

[0064]

[0065] S3, determine the water inlet temperature for heating the entire building;

[0066] According to the average heat dissipation temperature of the coil calculated in step S2, the water inlet temperature for heating the entire building is calculated with the highest average heat dissipation temperature.

[0067] According to Table 2, the maximum average temperature of the coil heat dissipation is greater than 45°C, and the minimum average temperature is less than 30°C. The inlet water temperature of the circuit is calculated based on the maximum average temperature of the coil heat dissipation in the main rooms (living room, bedroom) and the inlet and outlet water temperature difference is greater than 10, and the inlet water temperature is rounded up (while considering other buildings in the same heating community) as the inlet water temperature for heating the entire building. In this embodiment, the inlet water temperature for heating the entire building is 50°C.

[0068] S4. Calculate the inlet and outlet water temperatures and circulation flow rates of each coil corresponding to each household's water collector;

[0069] According to the total heat load of the room corresponding to each coil and the average heat dissipation temperature of the coil, and based on the inlet water temperature of the heating of the entire building in step S3 as the coil inlet water temperature, the outlet water temperature and circulation flow of the coil are calculated, and then the inlet and outlet water temperatures and circulation flow of each coil corresponding to each household's distribution and collection water tanks are determined.

[0070] Take the third coil on the first floor as an example. The third coil mainly provides heat to the south bedroom 2 of the household. The total heat dissipation of the coil is 1212W, the average heat dissipation temperature of the coil is 38.41℃, and the water inlet temperature of the whole building is 50.00℃.

[0071] The outlet water temperature is 38.41℃X2-50.00℃=26.82℃, the inlet and outlet water temperature difference is 50.00℃-26.82℃=23.18℃, and the circulation flow rate of the third coil on one layer is calculated as heat dissipation 1212W / inlet and outlet water temperature difference 23.18℃ / conversion coefficient 1.163=44.96 (Kg / h).

[0072] In addition, the first coil on the first floor is calculated. The first coil is used to heat the bathroom, dining room and kitchen of the household. The total heat dissipation of the coil is 1274W, the average heat dissipation temperature of the coil is 32.26℃, the inlet water temperature is 50.00℃, and the outlet water temperature is 32.26℃X2-50.00℃=14.52℃. Since the design room temperature of the bathroom is 16.00℃, the design room temperature of the kitchen is 16.00℃, and the design room temperature of the dining room is 18.00℃, the design outlet water temperature of the coil is calculated as 18.00℃, and the inlet and outlet water temperature difference is 50.00℃-18.00℃=32.00℃. Finally, the circulation flow rate of the first coil on the first floor is obtained as heat dissipation 1274W / inlet and outlet water temperature difference 32.00℃ / conversion coefficient 1.163=34.23(Kg / h).

[0073] According to the above method, the inlet and outlet water temperatures and circulation flow rates of each coil corresponding to each household's distribution and collection water tanks are calculated.

[0074] Table 4 Coil circulation flow calculation table (left household)

[0075]

[0076] Based on the inlet and outlet water temperatures and circulation flow of each coil, calculate the total heat dissipation, total circulation flow and the inlet and outlet water temperatures of the distribution and collection water tanks for each household.

[0077] The total heat dissipation of the first floor is the heat dissipation of the first circuit coil of the household 1274W + the heat dissipation of the second circuit coil 1363W + the heat dissipation of the third circuit coil 1212W + the heat dissipation of the fourth circuit coil 850W + the heat dissipation of the fifth circuit coil 646W = the total heat dissipation 5345W. The total circulation flow of the first floor is the circulation flow of the first circuit coil of the household 34.23Kg / h + the circulation flow of the second circuit coil 77.61Kg / h + the circulation flow of the third circuit coil 44.96Kg / h + the circulation flow of the fourth circuit coil 24.36Kg / h + the circulation flow of the fifth circuit coil 18.52Kg / h = 199.68Kg / h. The inlet water temperature of the household distribution and collection tank is 50.00℃, and the inlet and outlet water temperature difference is total heat dissipation 5345W / total circulation flow 199.68 (Kg / h) / conversion coefficient 1.163=23.02℃. The outlet water temperature is inlet water temperature 50.00℃-inlet and outlet water temperature difference 23.02℃≈27.00℃.

[0078] S5. Calculate the circulation resistance of each coil;

[0079] The circulation resistance of each household's inlet and outlet pipes and each coil is calculated based on the length of each household's inlet and outlet pipes, the length of each coil and the circulation flow of each coil, and the total circulation resistance of each household is also calculated.

[0080] According to the length and circulation flow of the inlet and outlet pipes and each coil of each household, the loss along the way and the local resistance are calculated by looking up the table, and the circulation resistance of the inlet and outlet pipes and each coil of each household is calculated. The total circulation resistance of the household is calculated based on the circulation resistance of the coil with the largest value. Therefore, the total circulation resistance of each household is the circulation resistance of the inlet pipe + the circulation resistance of the outlet pipe + the maximum circulation resistance of the indoor coil.

[0081] It should be noted that when calculating the local resistance coefficient of the pipeline, the local resistance coefficient of the filter and the water distributor should be included in the water inlet pipe, and the local resistance coefficient of the water collector should be included in the water outlet pipe.

[0082] S6. Based on the maximum circulation resistance value of the coil corresponding to each household's distribution and collection device, install a coil flow pressure regulating joint between the adapter joint and the water distributor corresponding to each remaining coil to adjust the circulation resistance of each coil to the maximum circulation resistance.

[0083] A coil pressure regulating orifice is fixed in the coil flow pressure regulating section. By adjusting the aperture of the coil pressure regulating orifice on different branches, the circulation resistance value of each coil is adjusted to be equal to the maximum circulation resistance.

[0084] like Figure 2 and 3 As shown, the pressure regulating joint 1 is a columnar structure as a whole, and its top inner wall is provided with an internal thread 5, which is adapted to the external thread of the water distributor branch pipe, and the bottom outer wall is provided with an external thread 4, which is adapted to the internal thread of the coil adapter; the pressure regulating orifice plate 2 is fixed in the inner cavity of the pressure regulating joint 1, and in order to enhance the sealing between the pressure regulating orifice plate 2 and the pressure regulating joint 1, rubber pads 3 are provided on both side panels of the pressure regulating orifice plate 2.

[0085] The aperture of the pressure regulating orifice plate 2 is calculated according to the following formula:

[0086] Formula 1:

[0087] Formula 2:

[0088] In the formula,

[0089] d——diameter of pressure regulating orifice, in mm;

[0090] D——Inner diameter of the pipe, which is 15.7mm according to the inner diameter of the floor heating coil;

[0091] △P——The pressure that the coil with pressure regulating orifice plate needs to consume. Its value is obtained by subtracting the circulation resistance value of the coil with the largest circulation resistance of the coils with several circuits in the distribution and collection device from the circulation resistance value of the coil that needs to be equipped with pressure regulating orifice plate. The unit is Pa.

[0092] G——Hot water circulation flow rate of the coil that needs to be equipped with a pressure regulating orifice plate, unit: kg / h;

[0093] ρ——density of hot water circulating in the floor heating coil. In this embodiment, the value is 992.24Kg / m based on the average temperature of the circulating hot water at 40°C. 3 .

[0094] Take the third-circuit coil on the first floor as an example to design the aperture of the pressure regulating orifice plate.

[0095] The household water collector has five coils. The second coil has the largest circulation resistance, which is 1329.37Pa. The third coil has a circulation resistance of 563.66Pa. The pressure △P consumed by this coil is the circulation resistance of the second coil 1329.37Pa minus the circulation resistance of this coil 563.66Pa=765.71Pa; the hot water flow rate G of this coil is 44.96kg / h; the hot water density p is 992.24Kg / m 3The inner diameter D of the floor heating coil is 15.7 mm. Substituting the calculation factor f into formula 2, the calculation factor f of this loop is 535.18, and substituting the value into formula 1, the diameter of the pressure regulating orifice plate is d = 4.55 mm.

[0096] In addition, the diameter of the pressure regulating orifice plate of the fifth coil on the first floor is also calculated. The circulation resistance of the fifth coil is 91.07Pa. The pressure △P consumed by this coil is the largest circulation resistance, which is the circulation resistance of the second coil 1329.37Pa minus the circulation resistance of this coil 91.07Pa = 1238.30Pa; the hot water flow rate G of this coil is 18.52kg / h; the hot water density p is 992.24Kg / m 3 ; The inner diameter D of the floor heating coil is 15.7mm. Substitute it into Formula 2 and Formula 1 respectively, and you will get the aperture d=2.65mm of the pressure regulating orifice plate that needs to be installed on the fifth coil. Since the aperture <3mm is not suitable for use in practice, it is necessary to consider installing a pressure regulating orifice plate at the inlet and outlet of the coil. Each pressure regulating orifice plate consumes half of the pressure, and the consumed pressure ΔP is 1238.30Pa / 2=619.15Pa. Substitute it into Formula 2 and Formula 1 again to find the aperture d=3.14mm of the pressure regulating orifice plate. For coils with similar pressure regulating plate apertures less than 3mm, two pressure regulating orifice plates are designed according to the above situation. The design calculation results of the apertures of the pressure regulating orifices of each coil carried by other distribution and collection devices are shown in Table 5.

[0097] Table 5 Coil pressure regulating orifice plate aperture calculation table (left side)

[0098]

[0099] S7. Thread the inlet flow regulating joint between the unit riser and each household’s inlet connecting pipe to make the total circulation resistance between each household equal.

[0100] The household flow pressure regulating orifice is fixed in the household flow pressure regulating section. By adjusting the aperture of the household flow pressure regulating orifice, the total circulation resistance between households is made equal, and at the same time, the circulation flow flowing into each household is ensured to reach the design value.

[0101] In this embodiment, an inlet flow pressure regulating section is installed before the pipe valve connecting the unit riser and each household system to serve as a pressure regulating device for flow distribution between households. The circulation flow of each household system reaches the design value by adjusting the aperture size of the pressure regulating orifice plate in the inlet flow pressure regulating section, so that the circulation resistance between each household is equal. The stop valve on the pipeline connecting the unit riser and each household system is replaced with a gate valve. The gate valve does not play a role in flow regulation, but only serves to shut off the inlet circulating water. In the present invention, the unit riser and the pipe connecting the riser and each household system are all welded steel pipes.

[0102] In this embodiment, the hydraulic balance calculation of the unit riser must take into account the influence of the natural additional pressure of gravity circulation generated by the hot water temperature drop. The natural additional pressure of gravity circulation generated by the hot water temperature drop is relative to the first floor, and the natural additional pressure of gravity circulation generated by the second, third, fourth, fifth and sixth floors relative to the first floor.

[0103] The existing building has a floor height of 2.9 meters. The heating water inlet temperature of the whole building is 50℃. The return water temperature is different for each household due to the different flow rates of each household. In actual operation, the influence of mass regulation is taken into account. The influence of the natural additional pressure of gravity circulation can be considered as 2 / 3 of the maximum value of the design condition. Since the natural additional pressure of gravity circulation is generated by the temperature drop of water, it is beneficial to the circulation of hot water, so it is subtracted from the circulation resistance of the loop. The height of the sixth floor relative to the first floor is 14.5m, the water inlet temperature is 50℃, and the water density is 988.07Kg / m 3 , the outlet water temperature is 26℃, and the water density is 996.70Kg / m 3 , the natural additional pressure of gravity circulation is:

[0104] 2 / 3x(996.70-988.07)x9.8x14.5=817.55Pa.

[0105] Table 6 Natural additional pressure calculation table (left side)

[0106]

[0107] After calculation, the maximum value of the circulation resistance in the unit riser system loop occurs in the circulation loop on the sixth floor, with a value of 5119.10Pa. Taking the circulation resistance of the household loop of 5119.10Pa as the base number and comparing it with the circulation resistance of other loops in the system, the system has hydraulic imbalance, and the maximum imbalance rate occurs in the circulation loop on the second floor, reaching 49.06%. On this basis, taking the circulation resistance of the sixth floor with the largest circulation pressure of 5119.10Pa as the base number, the difference between the circulation resistance of other loops and the maximum circulation resistance of 5119.10Pa is the surplus pressure of the loop, which is eliminated by the household flow pressure regulating orifice.

[0108] The calculation method of the inlet flow pressure regulating orifice plate aperture is the same as the calculation method of the coil pressure regulating orifice plate aperture. The calculation results are shown in the following table:

[0109] Table 7 Calculation table of the aperture of the pressure regulating orifice plate for household flow (left household)

[0110]

[0111] The present invention reasonably controls the water inlet flow of each coil carried by each household's distribution and collection device under the premise of the current pipe layout of the existing low-temperature hot water floor radiation, so that the thermal power of each room of each household tends to be balanced. At the same time, a regulating device (household flow pressure regulating section) for distributing the flow of the unit riser to the indoor system is added to regulate the flow of hot water delivered by the unit riser to each household. The use of a pressure regulating orifice plate can make the hydraulic balance of the system reach the ideal design state, which can solve the problem of indoor temperature imbalance in existing low-temperature hot water floor radiation heating buildings, reduce the indoor temperature difference of the building, and change the low temperature difference and large flow operation situation.

[0112] This method can be used to control the indoor temperature difference within the 20±2℃ specified in the specification; it can control the operating temperature difference of the low-temperature hot water floor radiant heating system within the 10℃ or greater specified in the specification. In this way, the circulation flow of the system can be reduced, and a circulating water pump with a small flow and low head can be used instead, reducing the electricity expenditure of the circulating water pump, which can achieve obvious social and economic benefits.

[0113] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0114] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling thermal balance of low-temperature hot water floor radiant heating in an existing building, characterized in that: The following steps are involved: S1. Calculate the heat load in each room; S2. Calculate the average temperature and heat dissipation of the coil in each room; S3, determine the water inlet temperature for heating the entire building; S4. Calculate the inlet and outlet water temperatures and circulation flow rates of each coil corresponding to each household and manifold: S5. Calculate the circulation resistance of each coil; S6. Based on the maximum circulation resistance value of the coil corresponding to each household's distribution and collection device, install a coil flow pressure regulating joint between the adapter joint and the water distributor corresponding to each remaining coil to adjust the circulation resistance of each coil to the maximum circulation resistance.

2. A thermal balance control method for low-temperature hot water floor radiant heating in an existing building according to claim 1, characterized in that: In step S1 , the heat load of each room in the building is calculated according to the code and the building envelope.

3. A thermal balance control method for low-temperature hot water floor radiant heating in an existing building according to claim 2, characterized in that: In step S2, the average temperature of the coil heat dissipation in each room is calculated according to the area of ​​each room, the heat load, and the laying spacing and area of ​​the coils, and then the heat dissipation of each coil in each household is calculated.

4. A thermal balance control method for low-temperature hot water floor radiant heating in an existing building according to claim 3, characterized in that: In step S3, according to the average heat dissipation temperature of the coil calculated in step S2, the water inlet temperature for heating the entire building is calculated with the highest average heat dissipation temperature.

5. A thermal balance control method for low-temperature hot water floor radiant heating in an existing building according to claim 4, characterized in that: In step S4, the outlet water temperature and circulation flow rate of the coil are calculated according to the total heat load of the room corresponding to each coil and the average heat dissipation temperature of the coil, and the inlet water temperature of the heating of the entire building in step S3 is used as the coil inlet water temperature, so as to determine the outlet water temperature and circulation flow rate of each coil corresponding to each household and manifold.

6. A thermal balance control method for low-temperature hot water floor radiant heating in an existing building according to claim 5, characterized in that: In step S4, the total heat dissipation, total circulation flow rate and the inlet and outlet water temperatures of the manifold and collector are calculated for each household according to the inlet and outlet water temperatures and circulation flow rate of each coil.

7. A thermal balance control method for low-temperature hot water floor radiant heating in an existing building according to claim 6, characterized in that: In step S5, the circulation resistance of each household's water inlet and outlet pipes and each coil is calculated according to the length of each household's water inlet and outlet pipes, the length of each coil and the circulation flow of each coil, and the total circulation resistance of each household is calculated at the same time.

8. The method for controlling thermal balance of low-temperature hot water floor radiant heating in an existing building according to claim 7, characterized in that: In step S6, a coil pressure regulating orifice is fixed in the coil flow pressure regulating section, and the circulation resistance value of each coil is adjusted to be equal to the maximum circulation resistance by adjusting the aperture of the coil pressure regulating orifice on different branches.

9. A thermal balance control method for low-temperature hot water floor radiant heating in an existing building according to claim 8, characterized in that: The method also includes step S7: threading an inlet flow regulating node between the unit riser and each household's inlet connecting pipe to make the total circulation resistance between each household equal.

10. A thermal balance control method for low-temperature hot water floor radiant heating in an existing building according to claim 9, characterized in that: In step S7, a household flow pressure regulating orifice is fixed in the household flow pressure regulating node. The aperture of the household flow pressure regulating orifice is adjusted to make the total circulation resistance between households equal, while ensuring that the circulation flow into each household reaches the design value.

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