A building minimum load calculation method

Abstract

This invention discloses a method for calculating the minimum load of a building, enabling objective and accurate calculation of the building's theoretical minimum load to guide refined building design and regulation. The method starts by identifying the thermal environment requirements of the micro-spaces surrounding the human body, deriving the building's theoretical minimum load and its data acquisition system. Based on actual climate conditions, human comfort needs, and the building's actual operating mode, and according to the first principles of heat and mass transfer processes within the complex "climate-building-human" building environment system, this invention proposes a minimum energy calculation method to maintain the comfort needs of the local control body of the human body. The steps are clear and simple, enabling thermal environment regulation to be reduced from the entire space to the local control body, and from the entire time to the local control time, providing architects and engineers with a theoretical basis and reference target for the refined design and regulation of the indoor thermal environment.

Description

Technical Field

[0001] This invention belongs to the field of building technology and relates to a method for calculating the minimum load of a building that takes into account actual climate conditions, the comfort needs of people, and the actual operation mode of the building. Background Technology

[0002] The construction industry's carbon emissions from building operation, construction, and infrastructure total approximately 2.35 billion tons of CO2, accounting for 24% of the nation's total carbon emissions. Building material production processes emit approximately 1.65 billion tons of CO2, accounting for 16%. This means that the total carbon emissions from the entire construction process (including material production, construction, operation, and demolition) account for 40% of the nation's total carbon emissions. Therefore, achieving dual-carbon targets in the construction industry is of paramount importance to achieving my country's overall dual-carbon goals.

[0003] Analyzing the specific technical routes for zero-carbon buildings, building energy demand can be categorized into heating and air conditioning, domestic hot water, and domestic electricity. For general residential and public buildings, the carbon emissions from heating and air conditioning account for the majority. Currently, mature heating and air conditioning technologies and design methods both domestically and internationally are designed for all spaces and all times, meaning they do not consider the refined spatial and temporal requirements. The indoor thermal and humidity environment created by a building should not come at the expense of human comfort. However, maintaining the specified indoor temperatures of 18℃ and 26℃ under a standard system for controlling all spaces and all times in winter and summer comes at a significant cost. This is because, from a heat transfer perspective, to achieve 18℃ and 26℃ across all spaces and times, there will inevitably be areas where indoor thermal parameters are higher than set values ​​in winter and lower than set values ​​in summer. With the further deepening of building energy conservation and carbon reduction efforts, the emergence of methods for creating partial spatial and temporal thermal environments, and the development of new end-point technologies, it has become urgent to propose a theoretical minimum load calculation method for buildings to facilitate practical engineering design.

[0004] Currently, the main technological pathways for achieving building energy conservation or reducing carbon emissions from building operations, both domestically and internationally, include: 1) improving the thermal performance of the building envelope, enhancing airtightness, and reducing heat transfer between indoors and outdoors; 2) improving the energy efficiency and control levels of equipment systems; and 3) increasing the utilization of renewable energy. Analogous to the Carnot limit in thermodynamics, this provides a reference target for fundamental researchers and engineers engaged in the research and development of thermal equipment systems. For the complex building environment system comprised of "climate-building-human," it is also necessary to define the minimum building load created by the above technological measures, ensuring user needs while minimizing the building's load. This minimum load will also provide a reference target for fundamental researchers and engineers in building design and HVAC design. The specific calculation process will be detailed below. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technologies and methods and to provide a method for calculating the minimum load of a building.

[0006] Firstly, this invention proposes a method for calculating the minimum load on a building, which includes two steps: calculating the room temperature and relative humidity of the building in its free-running state, and calculating the heat and mass transfer process between the human body and its surrounding environment.

[0007] First, calculate the room temperature (T) in the building's free-running state. b ) and relative humidity (RH) b The aim is to first obtain the indoor thermal environment parameters (T) created solely by the building itself, without relying on heating and air conditioning equipment. b and RH b Hourly values ​​or values ​​with higher precision are used to provide complex thermal boundary conditions for the second step. It can be seen that T... b and RH b This is a parameter matrix determined by the climate conditions of the building's location and the building's thermal performance. Therefore, its basic assumptions are:

[0008] (1) The building is in a natural ventilation condition (also known as a free-running state), that is, the heating and air conditioning equipment is in a closed state;

[0009] (2) When calculating the room temperature of a building in its free-running state, internal thermal disturbances such as lighting equipment should be considered.

[0010] (3) The human body and the hypothetical surrounding environment are in a state of thermal equilibrium, which is defined as a local control body in this invention;

[0011] (4) The inhalation temperature of the human body is equal to the room temperature of the building in its free-running state.

[0012] The calculation of room temperature in a building under free-running conditions can be performed using dynamic simulation software for building thermal environment such as DeST and EnergyPlus, or it can be performed based on a model established based on the dynamic heat transfer process.

[0013] The second step is to obtain the indoor thermal environment parameters (T) from the first step. b and RH b Based on the hourly values, further calculations are performed on the heat and mass transfer between the local human body control volume and its surrounding environment. To obtain the energy required for the local human body control volume to achieve comfort requirements, it is necessary to calculate the heat loss (Q) caused by moisture diffusion from the skin surface. 皮肤 Latent heat loss due to respiration (Q) 呼吸,潜热 ) and sensible heat loss (Q) 呼吸,显热 Heat loss due to sweating (Q) 出汗 Radiative heat transfer between the outer surface of clothing and the surrounding environment (Q)辐射 ), convective heat transfer between the outer surface of clothing and the surrounding environment (Q 对流 ), skin temperature (T) 皮肤 Physical quantities such as ) are calculated. First, the Fanger model is used to calculate the heat loss (Q) caused by water diffusion from the skin surface when the local control volume of the human body reaches thermal equilibrium. 皮肤 ):

[0014] Q 皮肤 =h w m(p sk -p b (1)

[0015] Where: h w ρ is the latent heat of vaporization of water; m is the skin's permeability coefficient; p sk p is the saturated vapor pressure at skin temperature. b This refers to the vapor pressure of a building when it is in a free-moving state.

[0016] Where, p sk The saturated vapor pressure at skin temperature is related to the skin temperature T. 皮肤 Relatedly, the saturated vapor pressure p of air at skin temperature can be calculated according to equation (2). sk Vapor pressure p of a building in free-running state b Based on the building's free-running room temperature and relative humidity obtained in step one, the saturated water vapor content (p) at that temperature can be calculated. 饱 And calculate p according to equation (3) b .

[0017]

[0018] p b =p 饱 RH b (3)

[0019] Latent heat loss due to respiration (Q 呼吸,潜热 ) and sensible heat loss (Q) 呼吸,显热 ):

[0020] Q 呼吸,潜热 =h w V(W ex -W in (4)

[0021] Q 呼吸,显热 =c p V(T ex -T in (5)

[0022] In the formula: V is the lung ventilation rate; W exW represents the moisture content of exhaled breath. in Moisture content of inhaled air (equal to RH) b );c p T is the specific heat capacity of dry air. ex T represents expiratory temperature. in Intake temperature (equal to T) b ).

[0023] The lung ventilation rate in equations (4) and (5) can be determined based on its empirical function with respect to the human metabolic rate, as shown in equation (6), where K res is a proportionality constant, M is the human metabolic rate, M can be found in ANSI / ASHRAE Standard 55-2020 or measured experimentally. Exhaled air temperature T ex and exhaled air humidity W ex It can be estimated based on the empirical formulas proposed by Fanger, as shown in equations (7) and (8), or it can be estimated based on other empirical formulas.

[0024] V=K res M (6)

[0025] T ex =32.6 + 0.066T b +32RH b (7)

[0026] W ex =0.0277+0.00065T b +0.8RH b (8)

[0027] Heat loss due to sweating:

[0028] Q 出汗 =0.42(M-58.2) (9)

[0029] Radiative heat exchange between the outer surface of clothing and the surrounding environment:

[0030] Q 辐射 =f eff f cl εδ(T cl 4 -T mrt 4 (10)

[0031] In the formula: f eff f is the effective radiation area factor (view factor); cl ε is the ratio of the surface area covered by clothing to the surface area of ​​the naked body; ε is the emissivity of the outer surface of the clothing; δ is the radiation constant; T cl Temperature of the outer surface of the garment; Tmrt The average radiant temperature of the building.

[0032] In equation (10) f cl It can be calculated using the formula in ISO 7730-2005 standard; T cl The calculation can be based on the T proposed by Fanger. cl with I c1 The relationship between them is determined, as shown in equation (11). Under natural convection, T... mrt Room temperature T in free-running state of the building b Black ball temperature T g The emissivity ε of the black ball g The diameter D of the black ball is related to the formula (12).

[0033] T c1 =35.7-0.028MI c1 3.96×10 8 ×f c1 [(T c1 +273) 4 -(T mrt +273) 4 ]+f c1 h c (T c1 -T b )}(11)

[0034]

[0035] Convective heat transfer between the outer surface of clothing and the surrounding environment:

[0036] Q 对流 =f cl h c (T cl -T b (13)

[0037] Where: h c The convective heat transfer coefficient between the clothing and the surrounding environment can be calculated using the formula in ISO 7730-2005.

[0038] Skin temperature T in thermal comfort state 皮肤 It can be calculated according to formula (14).

[0039] T 皮肤 =35.7-0.0275M (14)

[0040] The heat balance equation within the local control volume:

[0041] L = Q met -Q皮肤 -Q 呼吸,潜热 -Q 呼吸,显热 -Q 出汗 -Q 辐射 -Q 对流 +Q 最小 (15)

[0042] In the formula: L is the net load; Q met Equal to M; Q 最小 The minimum energy required to achieve thermal comfort in a localized area; a positive Q value 最小 A negative Q indicates that the human body has a need to be supplied with energy (heated). 最小 This indicates that the human body has a need to have energy removed (to be cooled down).

[0043] The thermal sensitivity coefficient TS can be calculated based on its relationship with M, as shown in equation (16), and PMV can be calculated based on its relationship with L and TS according to equation (17).

[0044] TS = 0.303e (-0.036M) +0.028 (16)

[0045] PMV = TS × L (17)

[0046] In the formula: TS is the thermal sensation coefficient. The 0.303, -0.036, and 0.028 in the above empirical formula are all empirical coefficients. Based on the research of Chinese scholars in the field of human thermal comfort in recent years, more refined models can also be established according to specific climate conditions, building types, user situations, etc.

[0047] It is also evident that the methods for obtaining metabolic rates and the underlying database are crucial for constructing the above empirical models. All the equations above are derived from the first principles of the complex built environment system comprised of "climate-building-human," thus possessing universality. However, for some empirical models and values, such as those concerning human thermal comfort, adaptive thermal comfort models can be used depending on the specific building operation mode.

[0048] Secondly, to achieve the above objectives, a complete data acquisition and computing system is needed to collect and process the data. This system includes information acquisition devices, user interaction devices, and intelligent computing devices.

[0049] The relevant parameters can be categorized into two types and set through sensor acquisition and user interaction devices, respectively: (1) Measurement is performed using sensors via an information acquisition system. The acquisition sensors include several temperature sensors, humidity sensors, air velocity sensors, and black bulb temperature sensors. The temperature sensor acquires the indoor air dry bulb temperature T. bBecause the thermal sensation of different parts of the human body has a significant impact on the overall thermal sensation, the measuring points are placed at corresponding heights of the head, abdomen, and ankles; the humidity sensor and the black sphere temperature sensor are used to detect the relative humidity (RH) of the air. b and air black sphere temperature t g The relative humidity and the average radiation temperature calculated from the black sphere temperature have a relatively weak impact on human comfort and are relatively uniformly distributed at different heights. Therefore, the measuring points are arranged at the height corresponding to the abdominal position of the sitting and standing human body. The sensor technical parameters of the data acquisition system are shown in Table 1. It should be noted that considering that the theoretical minimum load calculation method can be adapted to buildings in different climate zones in my country, the lower limit of the range of the indoor air dry bulb temperature under natural ventilation conditions in severely cold or cold regions and hot summer and warm winter regions is adjusted to -10℃ and the upper limit is adjusted to 50℃, respectively. Secondly, since the building is under natural ventilation and there is no active adjustment device, the upper limit of the range of air velocity is set to 3m / s. The black sphere temperature is generally higher than the air dry bulb temperature, so the range is 0~60℃. (2) Use the user interaction device to perform the corresponding interactive operation to obtain relevant data. This part of the data needs to be calculated by the user by looking up relevant standards to obtain empirical values ​​or empirical formulas and then input into the interaction device: saturated vapor pressure p at skin temperature. sk Retrieve data from a database given the skin temperature; the skin permeability coefficient m is taken as an empirical value; the specific heat capacity of dry air c... p The metabolic rate M is a constant; it can be retrieved from an empirical value based on the database embedded in the device; the effective radiation area factor f eff Empirical values ​​are taken based on human body condition; the emissivity ε of the outer surface of clothing is taken as a fixed value; the vapor pressure p of the building in free-moving state is taken as a fixed value. b The ratio f of the area covered by clothing to the area of ​​the naked body is calculated using an empirical formula based on relative humidity and temperature. cl The convective heat transfer coefficient h between clothing and the surrounding environment c The outer surface temperature T of clothing can be calculated using the empirical formula provided in ISO 7330-2005. cl Depending on the thermal resistance of the clothing, the user inputs visual data of the clothing they are wearing through a user interaction device. This visual data is then converted into a thermal resistance value, which is calculated by a computing device. c1 The data acquisition device and the user interaction device send the acquired information to the intelligent computing device, which then uses the minimum load calculation method to calculate the minimum load value based on the received information.

[0050] Table 1 Technical parameters of sensors used in the data acquisition system

[0051] Attached Figure Description

[0052] Figure 1 This is a flowchart of a method for calculating the minimum load of a building;

[0053] Figure 2 A schematic diagram of a local control body in the human body and its heat and mass transfer with the surrounding environment;

[0054] Figure 3 Typical architectural schematic diagram (circles indicate partial control volumes);

[0055] Figure 4 Schematic diagram of the data acquisition and minimum load calculation system. Detailed Implementation

[0056] This invention proposes a method for calculating the minimum load on a building, aiming to obtain the minimum energy required to maintain the comfort needs of a localized human body. The calculation method is as follows: Figure 1 As shown, the specific steps include:

[0057] Step 1: Obtain the room temperature and relative humidity of the building in its free-running state. The room temperature and relative humidity of the building in its free-running state can be calculated using dynamic simulation software for building thermal environment such as DeST and EnergyPlus, or it can be calculated based on a model established based on the dynamic heat transfer process.

[0058] Step two involves obtaining the minimum energy required to maintain comfort in the localized body of the human body. This requires, based on the first step of obtaining the building's room temperature and relative humidity under free-flowing conditions, and according to the principles of heat and mass transfer between the localized body of the human body and its surrounding environment, such as... Figure 2 As shown, the calculation model for constructing a local control body of the human body and its heat and mass transfer with the surrounding environment is realized, including the following steps.

[0059] Step S20, calculate the heat loss (Q) caused by moisture diffusion across the skin surface. 皮肤 As shown in equation (1), the saturated vapor pressure p at skin temperature sk The vapor pressure p of the building in its free-running state can be calculated according to equation (2). b The room temperature and relative humidity under the free-running state of the building can be calculated based on the information obtained in step one. The saturated water vapor content (p) at that temperature can be obtained by consulting a manual based on the room temperature under the free-running state. 饱 And calculate p according to equation (3). b h w is the latent heat of vaporization of water; m is the skin permeability coefficient.

[0060] Q 皮肤 =h w m( ps kp b (1)

[0061]

[0062] p b =p 饱 RH b (3)

[0063] Step S21, calculate the latent heat loss (Q) caused by respiration. 呼吸,潜热 ) and sensible heat loss (Q) 呼吸,显热 As shown in (4) and (5), this part of the heat loss is caused by the difference in state between the indoor air inhaled and the air exhaled. The inhaled air has the same state as the indoor air, i.e., T in =T b W in =RH b Latent heat loss Q 呼吸,潜热 c p Given the specific heat capacity of dry air, the lung ventilation rate V can be calculated using its empirical function with respect to M (6), K res M is a proportionality constant; its value can be found in ANSI / ASHRAES Standard 55-2020. Exhaled air temperature T ex and exhaled air humidity W ex It can be estimated based on the empirical formula proposed by Fanger, as shown in equations (7) and (8).

[0064] Q 呼吸,潜热 =h w V(W ex -W in (4)

[0065] Q 呼吸,显热 =c p V(T ex -T in (5)

[0066] V=K res M (6)

[0067] T ex =32.6 + 0.066T b +32RH b (7)

[0068] W ex =0.0277+0.00065T b +0.8RH b (8)

[0069] Step S22, calculate the heat loss Q caused by sweating. 出汗 As shown in equation (9), this part of the heat loss is mainly determined by the metabolic rate M.

[0070] Q 出汗=0.42(M-58.2) (9)

[0071] Step S23: Calculate the heat loss (Q) caused by radiative heat transfer between the outer surface of the garment and the surrounding environment. 辐射 As shown in equation (10), f eff Fanger used a photographic method to obtain the correction coefficient for the effect of human posture on the effective surface area, setting it at 0.7 for sitting and 0.72 for standing. cl It can be calculated according to the formula in ISO 7730-2005 standard; ε is the emissivity when wearing clothing, which can generally be taken as a fixed value of 0.95; δ is the radiation constant, which can generally be taken as a fixed value of 5.67×10. -8 w / m 2 ;T cl The calculation can be based on the T proposed by Fanger. cl with I c1 The relationship between them is determined, as shown in equation (11); under natural convection T mrt Room temperature T in free-running state of the building b Black ball temperature T g The emissivity ε of the black ball g The air temperature, black ball temperature and air velocity are related to the diameter D of the black ball and can be calculated according to formula (12), where the air temperature, black ball temperature and air velocity can be collected by the sensor.

[0072] Q 辐射 =f eff f cl εδ(T cl 4 -T mrt 4 (10)

[0073] T c1 =35.7-0.028MI c1 3.96×10 8 ×f c1 [(T c1 +273) 4 -(T mrt +273) 4 ]+f c1 h c (T c1 -T b )}(11)

[0074]

[0075] Step S24: Calculate the heat loss (Q) caused by convective heat transfer between the outer surface of the garment and the surrounding environment. 对流 As shown in equation (13), h cThe convective heat transfer coefficient between the clothing and the surrounding environment can be calculated using the formula in ISO 7730-2005.

[0076] Q 对流 =f cl h c (T cl -T b (13)

[0077] Step S25, skin temperature T under thermal comfort conditions 皮肤 It can be calculated according to formula (14);

[0078] T 皮肤 =35.7-0.0275M (14)

[0079] Step S26: Based on the human metabolic rate obtained in step S21, the thermal sensation coefficient TS can be calculated according to formula (15).

[0080] TS = 0.303e (-0.036M) +0.028 (15)

[0081] Step S27: Based on steps S20-S26, initialize parameter Q. 最小 =0, initialize intermediate parameters i=0, j=-1. Solve for the net load L according to equation (16), substitute the solved net load L into equation (17), calculate the value of PMV, and determine whether it is within the comfort range. If -0.5 < PMV < 0.5, then set equation (17) to 0. At this time, Q 最小 =0.

[0082] L = Q met -Q 皮肤 -Q 呼吸,潜热 -Q 呼吸,显热 -Q 出汗 -Q 辐射 -Q 对流 +Q 最小 (16)

[0083] PMV = TS × L (17)

[0084] Step S28: If PMV is not in the range (-0.5, 0.5), determine if PMV is greater than 0.5. If so, execute equation (18), assign i+1 to i, and execute equation (14) sequentially, setting Q... 最小 +i is then assigned to Q. 最小 Based on this, recalculate L in equation (16). After obtaining L, substitute it into equation (17) to calculate PMV. If PMV is still greater than 0.5, continue the loop calculation until -0.5 < PMV < 0.5. At this point, Q最小 It is the minimum value required to achieve the comfort standard.

[0085] Otherwise, it means PMV is less than -0.5, execute equation (20), assign j-1 to j, and execute equation (21) sequentially, setting Q... 最小 -j is then assigned to Q. 最小 Based on this, recalculate L in equation (16). After obtaining L, substitute it into equation (17) to calculate PMV. If PMV is still less than -0.5, continue the loop calculation until -0.5 < PMV < 0.5. At this point, Q 最小 It is the minimum value required to achieve the comfort standard.

[0086] i = i + 1 (18)

[0087] Q 最小 =Q 最小 +i (19)

[0088] j = j-1 (20)

[0089] Q 最小 =Q 最小 -j (21)

[0090] Example:

[0091] The following explanation uses a typical building as an example to illustrate the calculation process of the method of this invention.

[0092] A typical building is defined as a single-story residential building in the Xi'an area where a portion of the building space is occupied by people. The focus is on the people (circled) rather than the entire building space. Figure 3 As shown. This typical building is designed for energy conservation in accordance with the current national standard "Energy Conservation Design Standard for Residential Buildings in Severe Cold and Cold Regions" JGJ26-2018. All parameters of the building envelope are taken from the limits required by this standard. Assuming the occupants of the building space are seated, if the initial PMV value is greater than 0.5, it is assumed to be at the level of summer clothing with a thermal resistance of 0.5; if the initial PMV value is less than 0.5, it is assumed to be at the level of winter clothing with a thermal resistance of 1.0. The unit is Clo, where 1 Clo = 0.155 m. 2 • K / W, the indoor air velocity is assumed to be a representative medium air velocity, with a value of 1.0 m / s. Table 2 shows the basic parameters of the typical model.

[0093] Table 2. Values ​​of basic parameters for the enclosure structure of typical models.

[0094]

[0095] The ambient temperature and relative humidity of a building in its free-running state are calculated using dynamic building thermal environment simulation software such as DeST and EnergyPlus. Alternatively, calculations can be performed based on a model established using dynamic heat transfer processes, thereby obtaining the natural ambient temperature T0. b and relative humidity (RH) b To obtain the building's theoretical minimum load value, the calculation assumes no indoor heat source and operates under natural conditions year-round. After initializing relevant parameters and defining relevant intermediate variables, the building's room temperature and relative humidity under free-running conditions are calculated or simulated. Q is then calculated using the method described above. 皮肤 Q 呼吸，潜热 Q 呼吸，显热 Q 出汗 Q 辐射 Q 对流 TS is calculated by increasing or decreasing the net load L in resolution steps of 1W each time, and then calculating the PMV value. If the PMV value is still not within the comfort zone, the next resolution step, Q, is then calculated. 最小 The value is increased or decreased until the calculated PMV reaches the comfort range setting, thus creating a feedback loop between the net load calculation and the PMV calculation. To further illustrate Q... 最小 The relationship between the implementation process and architectural design, partial space control, or overall space control will be further explained here.

[0096] Assuming that the cooling / heating load that the local space control method can provide under this typical building is Q 局 Outdoor actual climate conditions - thermal comfort environment = required climate control, and required climate control - passive building regulation = active equipment regulation. Active equipment regulation can be divided into the adjustable load Q of local building spaces. 局 And the building's full-space control load Q 全 In practical applications, the following two situations may occur: when Q... 最小 <Q 局 Localized spatial control can be used; that is, the required climate control - passive building control = localized spatial control of equipment. When Q 最小 >Q 局 In this context, the required climate control – passive building regulation – equals the local spatial regulation of equipment plus the overall spatial regulation of equipment. This calculation method lays the theoretical foundation for constructing a personalized, self-regulating thermal environment service system for residents.

[0097] Using the above method, by changing the architectural design parameters and parameters related to the occupant's status in Table 2, the minimum load of other buildings can be calculated again. Regarding the relevant data collection and minimum load calculation system in practical applications, see... Figure 4 As shown.

[0098] This invention differs significantly from existing methods:

[0099] (1) In the traditional Fanger model, Q 最小 ≡0, meaning that the human body's thermoneutrality is considered to be entirely determined by T. b and RH b This decision also forms the theoretical basis for current domestic and international standards systems and engineering designs. In this invention, T... b and RH b For hourly or higher time precision, a parameter matrix determined by the climate conditions of the building's location and the building's thermal performance is provided, and a local human body control volume and Q are introduced. 最小 The concept of thermal comfort undoubtedly reduces the energy required to maintain human thermal comfort.

[0100] (2) Existing methods and technologies for creating thermal environments directly control T b and RH b The existing control methods target the entire building or room, neglecting fine-tuning of localized areas. This approach is inefficient in terms of energy utilization, making it difficult to reduce building energy consumption and carbon emissions at the source, regardless of improvements in system energy efficiency. This invention narrows the scope of thermal environment regulation from the entire space to a localized control area and from the entire time frame to a localized control time, providing architects and engineers with a theoretical basis for achieving refined design and regulation of indoor thermal environments.

[0101] (3) The energy-saving rate proposed by my country's current building energy-saving standard system considers the comprehensive performance of the complex whole of building and equipment systems, making it difficult for designers to assess the beneficial role of the building itself in building energy conservation and carbon reduction during the design stage. A calculation model for the energy-saving contribution rate of the building envelope based on dynamic heat transfer processes, human thermal comfort, and thermal adaptation models can obtain the contribution rate of the building itself in building energy conservation and carbon reduction, possessing significant theoretical value and practical operability. Based on this, this invention proposes a method for calculating the local control volume, local control time, and corresponding minimum building load, which conforms to the first principles of heat and mass transfer processes in complex building environments. This aims to provide fundamental support for refined design with the goal of maximizing energy consumption reduction and carbon emission reduction.

[0102] (4) Assuming that human thermal comfort requirements are constant, when climatic conditions are determined, the energy-saving rate proposed by my country's current building energy-saving standard system is a function of building thermal performance parameters, equipment system efficiency, etc.; the energy-saving contribution rate calculation model of the building envelope based on dynamic heat transfer process, human thermal comfort and thermal adaptation model requires T b and RH b It is only a function of building thermal performance parameters; Q 最小It depends not only on the building's thermal performance parameters, but also on the thermal resistance of indoor clothing, metabolic rate, and location of occupants. Therefore, through comparison, this invention has established first-principles principles for the heat and mass transfer process among the complex "climate-building-human" building environment system, and provides a solution that aligns with the current development of the construction industry.

[0103] This method of calculating the minimum load on buildings can be considered a novel approach. Starting from the search for the thermal environment requirements of the micro-spaces surrounding the human body, it derives the theoretical minimum load for buildings. As a calculation method, it considers actual climate conditions, human comfort needs, and the actual operating mode of buildings. Based on the first principles of heat and mass transfer processes within the complex "climate-building-human" building environment system, it proposes a minimum energy calculation method to maintain the comfort needs of the local control body of the human body. The steps are clear and simple. The concept of minimum load allows thermal environment control to be reduced from the entire space to the local control body, and from the entire time to the local control time, providing architects and engineers with a theoretical basis and reference target for achieving refined design and regulation of the indoor thermal environment.

Claims

1. A method for calculating the minimum load of a building, characterized in that, The method includes the following steps: Step 1: Obtain the room temperature and relative humidity of the building in its free-running state; Step two: Obtain the minimum energy required to maintain the comfort of the body's localized controls; Building free-running state room temperature T b and relative humidity (RH) b The calculations were performed using DeST and EnergyPlus building thermal environment dynamic simulation software, or a model based on the dynamic heat transfer process could be used. The minimum energy required to maintain the comfort of a local body control system needs to be achieved by first obtaining the room temperature and relative humidity of the building under free-flowing conditions. This is accomplished by constructing a calculation model of the heat and mass transfer between the local body control system and its surrounding environment, and then calculating the heat loss caused by moisture diffusion through the skin surface. Q 皮肤 Latent heat loss due to respiration Q 呼吸,潜热 ) and sensible heat loss ( Q 呼吸,显热 Heat loss due to sweating ( Q 出汗 Radiative heat transfer between the outer surface of clothing and the surrounding environment Q 辐射 ), convective heat transfer between the outer surface of clothing and the surrounding environment ( Q 对流 ), skin temperature ( T 皮肤 ) The parameter calculation model is as follows: Heat loss through water diffusion from the skin surface when the body reaches thermal equilibrium (i.e., when the local body reaches thermal equilibrium) Q 皮肤 ): In the formula: h w The latent heat of vaporization of water; m The skin's permeability coefficient; p sk The saturated vapor pressure at skin temperature; p b The vapor pressure when the building is in a free-moving state; Among them, the saturated vapor pressure at skin temperature p sk The vapor pressure of the building in its free-running state can be calculated according to equation (2). p b Based on the building's free-running room temperature and relative humidity obtained in step one, the saturated water vapor concentration at that temperature can be calculated. p 饱 And calculate according to formula (3) p b ; Latent heat loss due to respiration ( Q 呼吸,潜热 ) and sensible heat loss ( Q 呼吸,显热 ): In the formula: V Lung ventilation rate; W ex This refers to the moisture content of exhaled breath. W in The inhaled moisture content is equal to RH b ; c p The specific heat capacity of dry air; T ex Exhaled temperature; T in The intake temperature is equal to T b ; Lung ventilation rate in the formula V It can be determined based on an empirical function relating it to the human metabolic rate, as shown in equation (6), where K res It is a proportionality constant. M The human body's metabolic rate. M You can refer to ANSI / ASHRAE Standard 55-2020 or obtain the temperature of exhaled air through experimental methods. T ex and the moisture content of exhaled air W ex It can be obtained from the experimental instrument, or estimated according to the empirical formula proposed by Fanger, as shown in equations (7) and (8), or estimated according to other empirical formulas; Heat loss due to sweating: The radiative heat transfer between the outer surface of the garment and the surrounding environment is calculated using the following formula: Radiative heat exchange between the outer surface of clothing and the surrounding environment: In the formula: f eff The effective radiation area factor, also known as the field of view factor; f cl The ratio of the surface area covered by clothing to the surface area of ​​the naked body; ε δ is the emissivity of the outer surface of the garment; δ is the radiation constant. T cl The outer surface temperature of the garment depends on its thermal resistance. I c1 Different thermal resistance values ​​for clothing can be found in ANSI / ASHRAE Standard 55-2020. T mrt The average radiant temperature of the building. T cl The calculation can be based on Fanger's proposal. T cl and I c1 The relationship between them is determined, as shown in equation (11). T c1 =35.7-0.028(M-W)-I c1 {3.96×10 8 ×f c1 [(T c1 +273) 4 -(T mrt +273) 4 ]+f c1 h c (T c1 -T b )}(11) Convective heat transfer between the outer surface of clothing and the surrounding environment: In the formula: h c The convective heat transfer coefficient between the clothing and the surrounding environment; Skin temperature under thermal comfort conditions is calculated using the following formula: Skin temperature under thermal comfort conditions T 皮肤 It can be calculated according to equation (14): The heat balance equation within the local control volume: In the formula: L Net load; Q met Metabolic rate, equal to M ; Q 最小 The minimum energy required to achieve thermal comfort in localized areas of the body.

2. The method for calculating the minimum load of a building as described in claim 1, characterized in that, The thermal sensitivity coefficient is calculated using the following formula: thermal sensitivity coefficient TS Based on its relationship with M The relationship between them is calculated as shown in equation (16). PMV Based on its relationship with L and TS The relationship between them is calculated according to equation (17): In the formula: TS The coefficients 0.303, -0.036, and 0.028 in the above empirical formulas are all empirical coefficients. They can be updated based on research findings on human thermal comfort, or more refined models can be established based on specific climate conditions, building types, and user situations.

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