CN104896660A - Method for optimized setting of air conditioner temperature in office building - Google Patents

Abstract

The invention discloses a method for optimized setting of air conditioner temperature in an office building and relates to a dynamic setting method for changing a set value of the air conditioner temperature in real time according to indoor and outdoor environmental factors. To improve the dynamic setting of the air conditioner temperature, a simplified room thermodynamic model is established; in the model, the air conditioning opening is performed in the daytime, and natural ventilation is performed at night. The dynamic relations between the air conditioner load and environmental variables such as outdoor temperature, hot material temperature and the indoor temperature set value are established through the analysis of the room model. With the air conditioner load as an objective function and according to the limiting conditions that the human comfort index PMV value is within the regulated range, an optimized model of the air conditioner temperature set value is established; and optimization solution is performed on the model, so as to obtain the optimal air conditioner temperature set value at each moment. The obtained dynamic temperature set value can guarantee the good thermal comfort level for indoor workers and can effectively reduce energy consumption of the air conditioner.

Description

A kind of office building room conditioning temperature optimization establishing method

Technical field

The present invention relates to a kind of office building room conditioning temperature optimization establishing method.

Background technology

In larger office building, air conditioning energy consumption accounts for 40% of building total energy consumption, and along with larger office building increase and the requirement of people to comfort level improves day by day, air conditioning energy consumption rises rapidly, how to take effective measures on the basis ensureing human comfort that to reduce air conditioning energy consumption significant for building energy conservation.

Air-conditioner temperature setting is divided into fixed temperature to set and dynamic temperature sets two kinds, and the setting value of fixed temperature setting and air-conditioning is steady state value within a period of time, and the desired temperature of dynamic temperature setting and air-conditioning is change with time along with environmental changes such as outdoor temperatures.Traditional air-conditioner temperature setting method adopting fixed temperature setting more, therefore, mainly be based upon the research of air conditioner energy saving at present on the basis of fixed temperature setting, wherein three main directions are: reducing energy consumption, the design of office building structure energy-saving of air-conditioning system and manage energy-conservation.The reducing energy consumption of air-conditioning system mainly utilizes new technologies and materials to carry out reducing energy consumption to air-conditioning system, improves the utilization ratio with energy equipment in air-conditioning system.But because investment is huge or by the restriction of space, the use of this power-economizing method is subject to larger restriction.The design of office building structure energy-saving mainly reduces air conditioning energy consumption indirectly by the design that improves building enclosure and the measure such as air-tightness that improves door and window.This mode can only be applied in the design and construction stage of building.Manage and energy-conservationly mainly avoid the irrational operation of operations staff and the not energy-conservation use habit of air conditioner user by the energy-saving run system, code, staff training etc. improving air-conditioning and the energy consumption waste that causes.This method is subject to the subjective initiative restriction of related personnel.Dynamic air conditioning temperature setting method meets human comfort at the same time and saves the advantage that air conditioning energy consumption aspect has uniqueness.The equivalent temperature variation track of prediction outside air temperature and solar radiation and the index of establishment measurement human thermal comfort degree are the bases of research trends air-conditioner temperature establishing method.By change and the indoor occupant thermal comfort sensation of indoor and outdoor surroundings factor, adjustment air-conditioner temperature setting value is the key of dynamic air conditioning temperature setting method in real time, and existing technology is not very ripe in this respect, still needs and further improves.

Summary of the invention

Technical problem to be solved by this invention is, not enough for prior art, provides a kind of office building room conditioning temperature optimization establishing method.

For solving the problems of the technologies described above, the technical solution adopted in the present invention is: a kind of office building room conditioning temperature optimization establishing method, comprises the following steps:

1) outside air temperature, the equivalent temperature of solar radiation heat effect and outdoor combined air temperature T is predicted ₀;

2) thermodynamic analysis is carried out to office building room, set up equation of heat balance, obtained the dynamic relationship of air conditioner load and outdoor temperature, air-conditioner temperature setting value and hot mass temperature etc. by equation of heat balance, the object function of setting Optimized model;

3) hot comfort index PMV is calculated by the computational methods based on heat balance number HB, using pmv value setting within the limits prescribed as the constraints of air-conditioner temperature setting;

4) on the basis of above steps, set up air-conditioner temperature setting Optimized model, ask the method for energy consumption minimum of a value by linear programming technique, Optimized model is optimized and solves, obtain the optimum air-conditioner temperature setting value in each moment.

Described step 1) in, outdoor combined air temperature T ₀expression formula be:

T ₀＝T _w+T _q；

Wherein, $\begin{array}{c}{T}_w=T_{w.p}+(T_{w.\max }-T_{w.p})\sin \left[\mathrm{\ω}(t-t_0)\right]\\ =T_{w.p}+{\mathrm{\ΔT}}_w\sin \left[\mathrm{\ω}(t-t_0)\right]\end{array},$

T ₀represent outdoor combined air temperature, outdoor combined air temperature equals described equivalent temperature and outside air temperature sum, T _wrepresent outside air temperature, T _qrepresent the equivalent temperature of solar radiation, T _w.prepresent the mean value of outside air temperature on the same day, T _w.maxrepresent the maximum of outside air temperature on the same day, ω is the frequency of outside air temperature change, and value is π/12h ^-1, t represents the moment, t ₀represent the phase angle of outside air temperature change, △ T _wthe difference of outdoor air maximum temperature and outdoor air mean temperature, k ₀, k ₁, k ₂, k ₃, k ₄constant, k ₀, k ₁, k ₂, k ₃, k ₄value be to T by least square method _qcarry out curve fitting and to get.

Described step 2) in, equation of heat balance is:

Daytime:

${\mathrm{MC}}_m\frac{{\∂T}_m}{\∂t}={\mathrm{\α}}_o{S}_o(T_0-T_m)-{\mathrm{\α}}_i{S}_o(T_m-T_s);$

α _iS _o(T _m-T _s)+E＝-Q _cl

Night:

${\mathrm{MC}}_m\frac{{\∂T}_m}{\∂t}+{\mathrm{\α}}_o{S}_o(T_m-T_o)+{\mathrm{\α}}_i{S}_o(T_m-T_i)=0;$

ρC _pq _v(T _o-T _i)+α _iS _o(T _m-T _i)＝0

Wherein: M represents the quality of room exterior wall, C _mrepresent the specific heat capacity of exterior wall, T _mrepresent outer CALCULATE TEMPERATURE INSIDE WALL, α _orepresent the coefficient of heat transfer of exterior wall outer surface, α _irepresent the coefficient of heat transfer of exterior wall inner surface, S _orepresent the surface area of exterior wall, T _srepresent air-conditioner temperature setting value, E represents Indoor Thermal gain, Q _clrepresent air conditioner load, T _irepresent indoor temperature at night, ρ represents atmospheric density, C _prepresent air ratio thermal capacitance, q _vrepresent night ventilation rate.

The dynamic relationship of air conditioner load and outdoor temperature, air-conditioner temperature setting value, hot mass temperature is as follows:

Wherein, ζ=MC _m/ ρ C _pq _vrepresent based on night ventilation rate q _vtime constant, γ _o=α _os _o/ ρ C _pq _vrepresent nondimensional convection outside heat trnasfer number, γ _i=α _is _o/ ρ C _pq _vrepresent nondimensional internal convection heat trnasfer number, represent the phase shift of outer CALCULATE TEMPERATURE INSIDE WALL relative to outdoor temperature, C ₁be a constant, tried to achieve by boundary condition.

The computing formula of hot comfort index PMV is:

PMV＝2.43-3.76HB；

Wherein, t _skrepresent human body skin mean temperature, T _mrtthe mean radiant temperature of environment, M ₀represent that human metabolism leads, I _clrepresent the basic thermal resistance of clothes, I _arepresent air layer thermal resistance, f _clrepresent clothes area coefficient, I _a/ f _cl=0.1m ²dEG C/W.

Pmv value is set as :-0.9≤PMV≤0.9.

Air-conditioner temperature setting Optimized model is:

Wherein, t ₁for air-conditioning start-up time, t ₂for air-conditioning close moment, t ₁~ t ₂between be air-conditioning on daytime opening time section; represent the phase shift of outer CALCULATE TEMPERATURE INSIDE WALL relative to outdoor temperature; D ₁, D ₂represent weight coefficient, s _jrepresent the surface area on a room jth surface, wherein S ₀it is the surface area of exterior wall.

Compared with prior art, the beneficial effect that the present invention has is: the air-conditioner temperature setting value in the present invention is along with indoor and outdoor surroundings factor change with time, therefore, it is possible to people's thermal comfort level of guarantee indoor maintained constant level in one day.In the methods of the invention, indoor people's hot comfort level is better.In dynamic air conditioning temperature setting method of the present invention, morning and at dusk because the temperature of outdoor is lower, therefore, morning and at dusk air-conditioner temperature setting value set higher automatically, effectively can reduce air conditioning energy consumption, according to measuring and calculating, the inventive method can energy-conservation about 9% relative to fixed temperature setting value method.

Accompanying drawing explanation

Fig. 1 is office building room schematic diagram by day, Air conditioned on daytime, indoor air temperature T _iwith air-conditioner temperature setting value T _sequal.

Fig. 2 is the schematic diagram of office building room at night, night ventilation, and air-conditioning is closed.

Being labeled as in accompanying drawing: 1-room exterior wall, 2-room partition wall, the thermal source of 3-house interior, the internal heat material in 4-room.

Detailed description of the invention

The schematic diagram in office building room as depicted in figs. 1 and 2.In office building, daytime, (daytime referred to t ₁~ t ₂in time period, t can be got ₁=6, t ₂=18; Night refers to 0 ~ t ₁and t ₂~ 24 time periods) Air conditioned, indoor air temperature T _iwith air-conditioner temperature setting value T _sequal, night, air-conditioning was closed, and gravity-flow ventilation, night ventilation rate is q _v.The tables and chairs etc. of indoor are summed up as internal heat material.The body of wall in room is divided into exterior wall and partition wall.Have the face wall directly contacted to be exterior wall with outdoor environment, other walls are partition walls.Daytime, indoor all thermal enhancements were grouped into an internal heat resource, and its thermal enhancement is E; Night, indoor did not have thermal enhancement, namely night E=0.

In order to quantize the impact of outdoor environment on indoor thermal environment, the equivalent temperature of outside air temperature and solar radiation must be predicted.The equivalent temperature of outside air temperature and solar radiation and be outdoor combined air temperature, represent that outside air temperature and solar radiation are to the combined influence of indoor thermal environment.

Outside air temperature is expressed as:

T _w＝T _w.p+(T _w.max-T _w.p)sin[ω(t-t ⁰)]

(1)

＝T _w.p+△T _wsin[ω(t-t ₀)]

Wherein: T _wrepresent outside air temperature, T _w.prepresent the mean value of outside air temperature on the same day, T _w.maxrepresent the maximum of outside air temperature on the same day, ω value π/12h ^-1, t represents the moment, t ₀represent the phase angle of outside air temperature change.

The equivalent temperature of solar radiation is expressed as:

$T_q=\frac{{\mathrm{\ρ}}_{s}I}{{\mathrm{\α}}_e}---\left(2\right)$

Wherein: T _qrepresent the equivalent temperature of solar radiation, ρ _srepresent that building enclosure outer surface is to the absorption coefficient of solar radiation; I represents the solar irradiance on the same day, α _erepresent the building enclosure outer surface coefficient of heat transfer.

The equivalent temperature that above formula represents is unfavorable for the calculating of subsequent process, so carry out matching with a quartic polynomial to the equivalent temperature drawn by (2) formula, polynomial fitting is

K ₀, k ₁, k ₂, k ₃, k ₄be fitted polynomial coefficients, can draw in the process of matching.

Outdoor combined air temperature T ₀be expressed as:

T ₀＝T _w+T _q(4)

T _wand T _qdrawn by formula (1) and formula (3) respectively.

Room exterior wall is analyzed, room exterior wall itself can not produce heat, also can not consumption of calorie, therefore, the numerical value of the heat storing or discharge in room exterior wall temperature changing process equals the heat that room exterior wall and indoor and outdoor surroundings carry out obtaining in heat exchange process or losing.Analyze for indoor thermal environment, daytime, the load that air-conditioning exports will offset indoor thermal enhancement and outdoor environment is delivered to indoor thermal enhancement by room exterior wall in order to maintain the value of indoor air temperature.Therefore the equation of heat balance on daytime is:

${\mathrm{MC}}_m\frac{{\∂T}_m}{\∂t}={\mathrm{\α}}_o{S}_o(T_0-T_m)-{\mathrm{\α}}_i{S}_o(T_m-T_s)---\left(5\right)$

α _iS _o(T _m-T _s)+E＝-Q _cl(6)

Wherein: M represents the quality of room exterior wall, C _mrepresent the specific heat capacity of exterior wall, T _mrepresent outer CALCULATE TEMPERATURE INSIDE WALL, t represents the moment, α _orepresent the coefficient of heat transfer of exterior wall outer surface, α _irepresent the coefficient of heat transfer of exterior wall inner surface, S _orepresent the surface area of exterior wall, T _srepresent air-conditioner temperature setting value, E represents Indoor Thermal gain, Q _clrepresent air conditioner load, summer air-conditioning exports refrigeration duty, and its value is negative value.

Simultaneous (4) (5) (6) formula solves and obtains

Wherein: T _mrepresent outer CALCULATE TEMPERATURE INSIDE WALL, Q _clrepresent air conditioner load, ζ=MC _m/ ρ C _pq _vrepresent based on night ventilation rate q _vtime constant, γ _o=α _os _o/ ρ C _pq _vrepresent nondimensional convection outside heat trnasfer number, γ _i=α _is _o/ ρ C _pq _vrepresent nondimensional internal convection heat trnasfer number, represent the phase shift of outer CALCULATE TEMPERATURE INSIDE WALL relative to outdoor temperature, C ₁be a constant, tried to achieve by boundary condition.

Night, air-conditioning was closed, gravity-flow ventilation, and internal heat gain is zero, and the thermal balance mode at night is:

${\mathrm{MC}}_m\frac{{\∂T}_m}{\∂t}+{\mathrm{\α}}_o{S}_o(T_m-T_o)+{\mathrm{\α}}_i{S}_o(T_m-T_i)=0---\left(9\right)$

ρC _pq _v(T _o-T _i)+α _iS _o(T _m-T _i)＝0 (10)

Wherein: T _irepresent indoor temperature at night, ρ represents atmospheric density, C _prepresent air ratio thermal capacitance, q _vrepresent night ventilation rate.

Simultaneous (4) (9) (10) formula solves and obtains

Wherein: γ ' _i=γ _i/ (1+ γ _i); C ₂be constant, tried to achieve by boundary condition;

Respectively comprise a differential equation by day with in the equation of heat balance at night, so create two constant C in solution procedure ₁and C ₂.These two constants are tried to achieve by boundary condition.Assuming that the start time on daytime is t ₁, finish time is t ₂, i.e. t ₁with t ₂it is the boundary moment at daytime and night, because the variations in temperature of room exterior wall inner surface is continuous print, therefore at t ₁with t ₂the T that moment is tried to achieve by formula (7) and formula (11) _mvalue is equal.Therefore there are two relational expressions below:

At t ₁shi Keyou:

At t ₂shi Keyou:

Constant C can be solved by formula (12) and formula (13) ₁and C ₂value.

The PMV index calculating method weighing human comfort is:

PMV＝2.43-3.76HB (14)

$\mathrm{HB}=\frac{[T_{\mathrm{sk}}-(T_s+T_{\mathrm{mrt}})/2]/(I_{\mathrm{cl}}+I_a/f_{\mathrm{cl}})}{M_0}---\left(15\right)$

$T_{\mathrm{mrt}}=\frac{\underset{j=1}{\overset{5}{\mathrm{\Σ}}}{S}_j\·T_s}{\underset{j=0}{\overset{5}{\mathrm{\Σ}}}{S}_j}+\frac{S_0\·T_m}{\underset{j=0}{\overset{5}{\mathrm{\Σ}}}{S}_j}---\left(16\right)$

Wherein: HB represents heat balance number, PMV represents the average votes of prediction, T _skrepresent human body skin mean temperature, T _mrtthe mean radiant temperature of environment, M ₀represent that human metabolism leads, I _clrepresent the basic thermal resistance of clothes, I _arepresent air layer thermal resistance, f _clrepresent clothes area coefficient, S _jrepresent the surface area on j surface, room.

The calculating formula that simultaneous (14) (15) (16) formula obtains PMV is:

$\mathrm{PMV}=2.43-3.76\frac{{2T}_{\mathrm{sk}}-(D_1{T}_s+D_2{T}_m+T_s)}{2M_0(I_{\mathrm{cl}}+I_a/f_{\mathrm{cl}})}---\left(17\right)$

Wherein: $D_1=\frac{\underset{j=1}{\overset{5}{\mathrm{\Σ}}}{S}_j}{\underset{j=0}{\overset{5}{\mathrm{\Σ}}}{S}_j},D_2=\frac{S_0}{\underset{j=0}{\overset{5}{\mathrm{\Σ}}}{S}_j}.$

Indoor people is-0.9≤PMV≤0.9 to the requirement of hot comfort, substitutes into formula (17) and is expressed as:

$-0.9\≤2.43-3.76\frac{{2T}_{\mathrm{sk}}-(D_1{T}_s+D_2{T}_m+T_s)}{{2M}_0(I_{\mathrm{cl}}+I_a/f_{\mathrm{cl}})}\≤0.9---\left(18\right)$

Optimize the dynamic air conditioning desired temperature drawn, must meet and reduce air conditioning energy consumption to greatest extent under the prerequisite ensureing human thermal comfort.The absolute value of air conditioning energy consumption and air conditioner load is positive correlation, and therefore, with the minimum object function for optimizing of the absolute value sum of each moment air conditioner load, the air conditioner load in each moment is drawn by formula (8); In order to ensure human thermal comfort, with comfort level within the limits prescribed for constraints, constraints is drawn by formula (18), the variable T in its Chinese style (18) _mdrawn by formula (7), therefore formula (7) is the equality constraint of air-conditioner temperature setting value Optimized model.The Optimized model of air-conditioner temperature setting value is expressed as:

F represents object function---the absolute value sum of each moment air conditioner load, minf represents the minimum of a value asking object function.Solve the optimum air-conditioner temperature setting value that above-mentioned optimization problem can obtain each moment, the air-conditioner temperature setting value drawn is the dynamic value of a change with time, can reach under the prerequisite ensureing human comfort, significantly reduce the effect of air conditioning energy consumption.

Claims (7)

1. an office building room conditioning temperature optimization establishing method, is characterized in that, comprise the following steps:

1) outside air temperature, the equivalent temperature of solar radiation heat effect and outdoor combined air temperature T is predicted ₀;

2) thermodynamic analysis is carried out to office building room, set up equation of heat balance, obtained the dynamic relationship of air conditioner load and outdoor temperature, air-conditioner temperature setting value and hot mass temperature etc. by equation of heat balance, the object function of setting Optimized model;

3) hot comfort index PMV is calculated by the computational methods based on heat balance number HB, using pmv value setting within the limits prescribed as the constraints of air-conditioner temperature setting;

4) on the basis of above steps, set up air-conditioner temperature setting Optimized model, ask the method for energy consumption minimum of a value by linear programming technique, Optimized model is optimized and solves, obtain the optimum air-conditioner temperature setting value in each moment.

2. air-conditioner temperature Optimal Setting method according to claim 1, is characterized in that, described step 1) in, outdoor combined air temperature T ₀expression formula be:

T ₀＝T _w+T _q；

Wherein, $\begin{array}{c}{T}_w=T_{w.p}+(T_{w.\max }-T_{w.p})\sin \left[\mathrm{\ω}(t-t_0)\right]\\ =T_{w.p}+{\mathrm{\ΔT}}_w\sin \left[\mathrm{\ω}(t-t_0)\right]\end{array},$

T ₀represent outdoor combined air temperature, outdoor combined air temperature equals described equivalent temperature and outside air temperature sum, T _wrepresent outside air temperature, T _qrepresent the equivalent temperature of solar radiation, T _w.prepresent the mean value of outside air temperature on the same day, T _w.maxrepresent the maximum of outside air temperature on the same day, ω is the frequency of outside air temperature change, and value is π/12h ^-1, t represents the moment, t ₀represent the phase angle of outside air temperature change, △ T _wthe difference of outdoor air maximum temperature and outdoor air mean temperature, k ₀, k ₁, k ₂, k ₃, k ₄constant, k ₀, k ₁, k ₂, k ₃, k ₄value be to T by least square method _qcarry out curve fitting and to get.

3. air-conditioner temperature Optimal Setting method according to claim 2, is characterized in that, described step 2) in, equation of heat balance is:

Daytime:

${\mathrm{MC}}_m\frac{{\∂T}_m}{\∂t}={\mathrm{\α}}_o{S}_o(T_0-T_m)-{\mathrm{\α}}_i{S}_o(T_m-T_s);$

α _iS _o(T _m-T _s)+E＝-Q _cl

Night:

${\mathrm{MC}}_m\frac{{\∂T}_m}{\∂t}={\mathrm{\α}}_o{S}_o(T_0-T_m)-{\mathrm{\α}}_i{S}_o(T_m-T_s)=0;$

ρC _pq _v(T _o-T _i)+α _iS _o(T _m-T _i)＝0

Wherein: M represents the quality of room exterior wall, C _mrepresent the specific heat capacity of exterior wall, T _mrepresent outer CALCULATE TEMPERATURE INSIDE WALL, α _orepresent the coefficient of heat transfer of exterior wall outer surface, α _irepresent the coefficient of heat transfer of exterior wall inner surface, S _orepresent the surface area of exterior wall, T _srepresent air-conditioner temperature setting value, E represents Indoor Thermal gain, Q _clrepresent air conditioner load, T _irepresent indoor temperature at night, ρ represents atmospheric density, C _prepresent air ratio thermal capacitance, q _vrepresent night ventilation rate.

4. air-conditioner temperature Optimal Setting method according to claim 3, is characterized in that, the dynamic relationship of air conditioner load and outdoor temperature, air-conditioner temperature setting value, hot mass temperature is as follows:

Wherein, ζ=MC _m/ ρ C _pq _vrepresent based on night ventilation rate q _vtime constant, γ _o=α _os _o/ ρ C _pq _vrepresent nondimensional convection outside heat trnasfer number, γ _i=α _is _o/ ρ C _pq _vrepresent nondimensional internal convection heat trnasfer number, represent the phase shift of outer CALCULATE TEMPERATURE INSIDE WALL relative to outdoor temperature, C ₁be a constant, tried to achieve by boundary condition.

5. air-conditioner temperature Optimal Setting method according to claim 4, is characterized in that, the computing formula of hot comfort index PMV is:

PMV＝2.43-3.76HB；

Wherein, t _skrepresent human body skin mean temperature, T _mrtthe mean radiant temperature of environment, M ₀represent that human metabolism leads, I _clrepresent the basic thermal resistance of clothes, I _arepresent air layer thermal resistance, f _clrepresent clothes area coefficient, I _a/ f _cl=0.1m ²dEG C/W.

6. air-conditioner temperature Optimal Setting method according to claim 5, is characterized in that, be set as by pmv value :-0.9≤PMV≤0.9.

7. air-conditioner temperature Optimal Setting method according to claim 6, is characterized in that, air-conditioner temperature setting Optimized model is:

Wherein, t ₁for air-conditioning start-up time, t ₂for air-conditioning close moment, t ₁~ t ₂between be air-conditioning on daytime opening time section; represent the phase shift of outer CALCULATE TEMPERATURE INSIDE WALL relative to outdoor temperature; D ₁, D ₂represent weight coefficient, s _jrepresent the surface area on a room jth surface, wherein S ₀it is the surface area of exterior wall.