RU2636807C1 - Estimation method of microclimate comfort in premises of habitable, public and office buildings - Google Patents

Abstract

FIELD: ventilation.

SUBSTANCE: in the described method, which consists in measuring the indoor air temperature, relative humidity, air mobility, ambient temperature, preliminarily determine the preferred type and characteristics of the work performed, as well as the thermal conductivity resistance of the people's clothing preferred type, additionally measure the person clothing surface temperature, the carbon dioxide concentration in the air of the premise under examination and in the outdoor air, calculate the components of the person heat balance equation, determine the coefficient of human thermal condition comfort coefficient k₁, the radiative cooling coefficient k₂, the radiation fluxes asymmetry coefficient k₃, the air medium quality coefficient k₄. Calculate the comfort level of the microclimate according to the formula: W = k₁⋅k₂⋅k₃⋅k₄, and estimate the comfort level of the microclimate according to the following scale: <-0.5 - cold, discomfort, -0.3÷-0.5 - cool, light discomfort, 0÷-0.3 - cool, but comfortable, 0 - comfort, 0÷0.3 - heat, but comfortable, 0.30÷0.5 - heat, slight discomfort.

EFFECT: increasing the accuracy of determining the comfort level in the premises of habitable, public and office buildings.

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Description

The invention relates to systems for monitoring the efficiency of heating, ventilation and air conditioning systems in residential, public and administrative buildings and can be used in the design, reconstruction and optimization of the operating modes of these systems, as well as in the development and implementation of energy-saving measures.

Widely known methods for determining the comfort of a microclimate, including measuring and evaluating its individual components: temperature, mobility, relative humidity of indoor air, as well as the characteristics of thermal radiation. An example is GOST 30494-2011 “Residential and public buildings. The microclimate parameters in the premises ", as well as SanPiN 2.2.4.548-96" Hygienic requirements for the microclimate of industrial premises ".

A significant drawback of these methods is the neglect of air quality, as well as the mutual influence of microclimate factors on each other and on the human body.

Closest to the technical nature of the claimed is a method for assessing the comfort of the working area according to the microclimate parameters (patent for invention RU No. 2509322, IPC G01W 1/02, 2012), adopted as a prototype. The indicated method consists in first measuring the air temperature using a psychrometer, then measuring the air humidity using a stationary psychrometer and determining the air speed using anemometers, and then, based on the obtained parameters, the air temperature in the working area, its humidity and speed, as well as the temperature surrounding surfaces in the working area - calculate the degree of comfort according to the following formula:

S = 7.83-0.1t _B -0.0968t _O -0.0372P + 0.18v (37.8-t _B ),

where t _B - air temperature in the working area of the production room; t _O is the temperature of the surrounding surfaces in the working area; v is the air velocity, m / s;

P is the partial pressure of water vapor, calculated by the formula:

P = 0.01ϕ × P _us , mmHg,

where ϕ is the relative humidity,%; P _us - the partial pressure of water vapor in a saturated state, after which they evaluate the comfort of the microclimate parameters on the following scale: 1 - very hot; 2 - too warm; 3 - warm, but nice; 4 - a sense of comfort; 5 - cool, but nice; 6 - cold; 7 - very cold; characterized in that they measure: air temperature and its humidity using a stationary VIT-2 psychrometer, air velocity using an ATE-1034 digital anemometer, and the temperature of surrounding surfaces in the working area using a contact thermometer with an immersion probe of the TK5 type. 01M.

The disadvantage of this solution is its applicability exclusively to industrial premises and the lack of consideration of the mutual influence of parameters on each other and on the comfort of the microclimate.

The technical result consists in increasing the accuracy of determining the level of comfort of premises of residential, public and administrative buildings by expanding the range of parameters taken into account when assessing the level of comfort of the microclimate, as well as analyzing the hazards that are typical only for premises of residential, public and administrative buildings.

The technical result is achieved by the fact that in the method of assessing the comfort of the microclimate in the premises of residential, public and administrative buildings, which consists in measuring the indoor air temperature, relative humidity, air mobility, temperature of the surrounding surfaces, the preferred type and characteristics of the work performed, as well as resistance, are preliminarily determined thermal conductivity of the predominant type of people's clothing, additionally measure the surface temperature of human clothing, the concentration of dioxide and carbon in the air of the test room and in the outdoor air, calculate the components of the equation of the heat balance of a person, calculate the coefficient of comfort of the heat state of a person k ₁ by the formula: k ₁ = (q _n -q _f ) / q _n ,

where q _n is the amount of thermal energy that must be removed from the surface of the human body to ensure a comfortable thermal state for a given type of work performed in the room, q _f is the amount of heat actually removed from the surface of the human body (W / m ² ).

Calculate the value of the asymmetry of radiation by the formula:

Δt _a = t _{p, max} -t _{p, min} ,

where t _{p, max} - the maximum temperature of the surrounding surfaces of the room, ° C;

t _{p, min} - the minimum temperature of the surrounding surfaces of the room, ° C;

The value of the coefficient of radiation cooling k _{2 is} determined:

at t _in -t _{p, min} > 2 is calculated by the formula: k ₂ = (q _n -q _{l, t} ) / q _n , where q _{l, t} is the radiant heat flux leaving the surface of the human body to the coldest surrounding surface premises, t _in - air temperature in the room, ° С,

when t _in -t _{p, min} ≤2 take k ₂ = 1.

The value of the asymmetry coefficient of the radiation flux k _{3 is} determined:

when Δt _a > 3.9 + 1.8 R ₀ , where R ₀ is the thermal conductivity resistance of the predominant type of clothing of people in the room,

calculated by the formula: k ₃ = 1-0.01 (0.17Δt _a ² + 0.72Δt _a -2.12),

when Δt _a ≤3.9 + 1.8 R ₀ take k ₃ = 1.

The excess concentration of carbon dioxide C in the room is calculated according to the formula: C = C _p -C _o ,

where C _p is the concentration of carbon dioxide in the room air, ppm; With _o - the concentration of carbon dioxide in the outdoor air, ppm.

The value of the air quality factor k _{4 is} determined:

at C> 400, it is calculated by the formula: k ₄ = -0,00045C + 1.18,

when C≤400 take k ₄ = 1.

The microclimate comfort level is calculated by the formula:

W = k ₁ ⋅k ₂ ⋅k ₃ ⋅k ₄ ,

and evaluate the level of microclimate comfort on the following scale:

The method is implemented as follows.

First, the preferred type and characteristics of the work performed in the examined room are determined (metabolic heat, referred to 1 m ^{2 of the} surface of the human body - q _mt , W / m ² ; the efficiency of mechanical work - η; the relative speed of motion in still air - v ₀ , m / s).

Determine the thermal conductivity resistance R ₀ , clo, the predominant type of clothing of people in the room.

Measure the air temperature t _in , ° C; relative humidity ϕ,%; surface temperature of human clothing t _o , ° C; air mobility - ν, m / s; the temperature of the surrounding surfaces t _{p, i} , ° C, at three points remote from each other by more than 0.5 m; the concentration of carbon dioxide (CO ₂ ) in the air of the inspected room With _p , cm ³ / m ³ (ppm) and the concentration of carbon dioxide (CO ₂ ) in the outside air - With _o , cm ³ / m ³ (ppm). Measurements are carried out, for example, with the testo-435-1 multifunction measuring instrument or other certified measuring instruments entered in the State Register of Measuring Instruments. Choose the maximum t _{p, max} and minimum t _{p, min} temperatures of the surrounding surfaces of the room.

The components of the heat balance equation of a person are calculated.

The heat flux, which must be removed by radiation and convection from the surface of the human body to ensure its comfortable thermal state, is calculated by the formula:

q _n = q _mp -q _dp -q _un -q _ds -q _qa ,

where q _tp is the internal heat production of the human body, W / m ² ;

q _DP - heat loss through the skin due to vapor diffusion, W / m ² ;

q _ip - the heat loss from the skin surface by evaporation of moisture, W / m ^2;

q _ds - latent heat loss during breathing, W / m ² ;

q _AH - explicit heat loss during breathing, W / m ^2.

The internal heat production of the human body is calculated as

q _mp = q _mt (1-η),

where q _mt is the metabolic heat (energy of the oxidation process occurring in the human body), referred to the unit surface of the human body, W / m ² ;

η is the efficiency of mechanical work.

Heat loss through human skin due to the vapor diffusion process q _{dp is} calculated by the formula:

q _dp = 0.41 (1.92t _to -25.3-p _in ),

where t _to - human skin temperature;

t _k = 35.7-0.032⋅q _mp = 35.7-0.032⋅q _mt (1-η);

p _in - the partial pressure of water vapor in moist air, mm Hg:

The amount of heat spent on the evaporation of liquid from the surface of the human body is calculated by the expression:

q _un = 0.49 (q _mp -50) = 0.49 (q _MT (1-η) -50).

The latent heat released during breathing is calculated by the formula:

q _ds = 0.0027q _mt (44-p _in ).

The apparent heat released during breathing is calculated by the formula:

q = 0,0014q _{AH MT} (34 _a-t).

The heat flux actually removed from the surface of the human body by convection and radiation is calculated as:

q _f = q _l + q _k ,

where q _l is the loss of heat from the surface of clothing and uncoated clothing on the surface of the human body due to radiation, W / m ² ;

q _to - heat loss from the surface of clothes and uncoated clothing of the surface of the human body due to convection, W / m ² .

The heat flux leaving the surface of a person’s clothing due to radiation is calculated by the formula:

q _l = 3,629⋅10 ^-8 ⋅ [(t _о +273) ⁴ - ((t _{p, о} +273) ⁴ ],

where t _{p, о} is the average radiation temperature of the room, which for approximate calculations is taken 2 ° C below air temperature:

t _{p, o} = t _in -2.

Calculate the convective heat flux leaving the surface of the human body:

- in still air (v = 0 m / s):

_to q = 2,4 (t _a -t _b) ^1.25;

- with forced convection and 0.1 <ν <2.6 m / s:

The comfort coefficient of a person’s thermal state k _{1 is} calculated:

Further, the effects on the comfort level of radiation cooling are taken into account. To do this, calculate the radiant heat flux leaving the surface of the human body on the coldest surface of the room:

q _{l, t} = 0.605 × 10 ^-8 [(t _o +273) ⁴ - ((t _{p, min} +273) ⁴ ].

The coefficient of radiation cooling k ₂ :

- at t _in -t _{p, min} ≤2:

k ₂ = 1;

- at t _in -t _{p, min} > 2:

Calculate the effect on the comfort level of the asymmetry of radiation. To do this, calculate the value of the asymmetry of radiation according to the formula:

Δt _a = t _{p, max} -t _{p, min} .

The asymmetry coefficient of the radiation flux k ₃ :

- at Δt _a ≤3.9 + 1.8R ₀ :

k ₃ = 1;

at Δt _a > 3.9 + 1.8R ₀ :

Next, determine the effect on the comfort level of air quality. To this end, calculate the excess concentration of CO ₂ in the room:

C = C _p -C _about .

And determine the air quality factor k ₄ :

- at C <400:

k ₄ = 1;

- at C> 400:

k ₄ = -0,00045 ° C + 1.18.

Then calculate the comfort level of the microclimate according to the formula

W = k ₁ ⋅k ₂ ⋅k ₃ ⋅k ₄ .

The level of comfort corresponding to the level is determined on a scale.

An example implementation of the proposed method

It is required to determine the level of comfort in the premises of the training laboratory if:

the metabolic heat characteristic of this type of work is q _mt = 93 W / m ² , the efficiency of mechanical work is η = 0; relative speed in still air - v ₀ = 0 m / s. Students present in the room are dressed in light trousers and short-sleeved shirts, the estimated resistance to heat transfer of clothing is R _o = 0.5 clo.

The experimental values of the microclimate parameters are determined using the multifunctional measuring device testo-435-1:

indoor air temperature t _in , = 24 ° С;

relative humidity in the room ϕ = 15%;

indoor air mobility ν = 0.05 m / s;

the average surface temperature of students ’clothing t _o = 29 ° C;

the minimum temperature of the surrounding surfaces t _{p, min} = 14 ° C,

maximum temperature of surrounding surfaces t _{p, max} ; = 20 ° С;

the concentration of carbon dioxide in the air of the room With _p = 350 ppm;

the concentration of carbon dioxide in outdoor air With _about = 30 ppm.

Internal heat production of the human body:

q _mp = q _mt (1-η) = 93⋅ (1-0) = 93 W / m ² .

Human skin temperature:

t _k = 35.7-0.032⋅q _mp = 35.7-0.032⋅q _mt (1-η) = 35.7-0.032⋅93 = 32.7 ° С.

Partial pressure of water vapor in moist air:

Heat loss through human skin due to vapor diffusion:

q _dp = 0,41 (1,92t -25.3 _to-r) = 0,41 (1,92⋅32,7-25,3-27,09) = 4,26 W / m ^2.

The amount of heat spent on the evaporation of liquid from the surface of the body:

q _un = 0.49 (q _mp -50) = 0.49 (q _mt (1-η) -50) = 0.49 (93-50) = 21.07 W / m ² .

Latent heat released during breathing:

q _ds = 0.0027q _mt (44-p _in ) = 0.0027⋅93 (44-27.09) = 4.25 W / m ² .

Explicit heat released during breathing:

q = 0,0014q _{AH MT} (34 _a-t) = 0,0014⋅93 (34-24) = 1,302 W / m ^2.

The heat flux that must be removed by radiation and convection from the surface of the human body to ensure its comfortable thermal state:

q = q _{mn n} -q _dp -q _un -q _x = -q _AH 93-4,26-21,07-4,25-1,302 = 62.12 W / m ^2.

The heat flux leaving the surface of a person’s clothing due to radiation:

q _l = 3,629⋅10 ^-8 ⋅ [(t _o +273) ⁴ - (t _{p, o} +273) ⁴ ] = 3,629⋅10 ^-8 ⋅ [(29 + 273) ⁴ - (22 + 273) ⁴ ] = 33.78 W / m ² ;

where is the average radiation temperature of the room:

t _{p, o} = t _in -2 = 24-2 = 22 ° C.

Convective heat flux leaving the surface of the human body due to convection:

The heat flux that is actually removed from the surface of the human body through convection and heat radiation:

q _f = q _L + q _k = 33.78 + 13.53 = 47.31 W / m ² .

The comfort indicator of a person’s thermal state k ₁ :

Radiant heat flux leaving the surface of the human body to the coldest surface of the room:

q _{l, t} = 0.605⋅10 ^-8 ⋅ [(t _o +273) ⁴ - ((t _{p, min} +273) ⁴ ] = 0.605⋅10 ^-8 ⋅ [(29 + 273) ⁴ - (14 + 273 ) ⁴ ] = 9.46.

t _at -t _{p, min} = 24-14 = 10 ° C.

The coefficient of radiation cooling at t _in -t _{p, min} > 2:

Asymmetry of radiation Δt _a :

Δt _a = t _{p, min} -t _{p, min} = 20-14 = 6 ° C.

3.9 + 1.8R ₀ = 3.9 + 1.8⋅0.5 = 4.8.

The asymmetry coefficient of radiation at Δt _a > 3.9 + 1.8R ₀ :

We calculate the excess concentration of CO ₂ in the room:

C = C _p -C _o = 350-30 = 320 ppm.

When C <400 k ₄ = 1.

We calculate the microclimate comfort level by the formula:

W = k ₁ ⋅k ₂ ⋅k ₃ ⋅k ₄ = 0.24⋅0.85⋅0.92⋅1 = 0.19.

We conclude about the level of comfort, on a scale the level of comfort equal to W = 0.19, corresponds to the state of a person “warm, but comfortable”.

Claims (18)

A method for assessing the comfort of a microclimate in residential, public and administrative buildings, which consists in measuring indoor air temperature, relative humidity, air mobility, temperature of surrounding surfaces, characterized in that the preferred type and characteristics of the work performed, as well as the thermal conductivity of the preferred type are preliminarily determined clothes of people, in addition measure surface temperature of clothes of the person, concentration of carbon dioxide in air obs eduemogo premises and the outside air is calculated equates human thermal balance coefficient is calculated human thermal comfort condition by the formula k _1: k ₁ = (q _n -q _p) / q _n, where q _n - the amount of thermal energy that must be removed from the surface of the human body to ensure its comfortable thermal condition for a given type of work performed in the room, W / m ² ; q _f - the amount of heat actually removed from the surface of the human body, W / m ² , calculate the asymmetry of radiation radiation by the formula Δt _a = t _{p, max} -t _{p, min} , where t _{p, max} is the maximum temperature of the surrounding surfaces of the room, ° C, t _{p, min} is the minimum temperature of the surrounding surfaces of the room, ° C; determine the value of the coefficient of radiation cooling k ₂ : at t _in -t _{p, min} > 2 is calculated by the formula: k ₂ = (q _n -q _{l, t} ) / q _n , where q _{l, t} is the radiant heat flux leaving the surface of the human body to the coldest surrounding surface premises, t _in - air temperature in the room, ° C, when t _in -t _{p, min} ≤2 take k ₂ = 1, determine the coefficient of asymmetry of the radiation flux k ₃ : when Δt _a > 3.9 + 1.8 R ₀ , where R ₀ is the thermal conductivity resistance of the predominant type of clothing of people in the room, the clo is calculated by the formula: k ₃ = 1-0.01 (0.17Δt _a ² + 0.72Δt _a -2,12), when Δt _a ≤3.9 + 1.8R ₀ take k ₃ = 1, calculate the excess concentration of carbon dioxide in the room according to the formula: C = C _p -C _o , where C _p - the concentration of carbon dioxide in the room air, ppm; With _{o the} concentration of carbon dioxide in the outdoor air, ppm, determine the value of the air quality factor k ₄ : at C> 400, it is calculated by the formula: k ₄ = -0,00045 C + 1.18, when C≤400 take k ₄ = 1, calculate the comfort level of the microclimate according to the formula: W = k ₁ ⋅k ₂ ⋅k ₃ ⋅k ₄ , and evaluate the level of microclimate comfort on the following scale: