A building energy-saving design method based on annual heat gain and loss analysis

Abstract

The present invention provides a building energy-saving design method based on year-round heat gain and loss analysis. First, the building's geometric information and thermal calculation parameters, as well as information such as personnel, equipment, and lighting power density and operating hours, are determined. Second, the building's annual energy consumption is calculated, and the building's heat gain and heat loss components are statistically analyzed by season. The heat gain and loss items in different seasons are sorted to obtain the main heat gain and heat loss items at the building level and between room levels. Based on the sorting results, energy-saving design strategies are proposed at the building level and room level, and the priority of these energy-saving design strategies is determined. The annual comprehensive benefits of a single energy-saving design strategy in a certain season are examined. If the annual comprehensive benefit is less than zero, the building plan is redesigned. If it is greater than zero, multiple single strategies are combined and designed, and the building's annual energy consumption and energy-saving rate under different combinations are calculated. The combined operating condition with the greatest energy-saving potential and the energy-saving rate level under this condition are determined.

Description

Technical Field

[0001] The present invention belongs to the field of building energy-saving design, and in particular relates to a building energy-saving design method based on annual heat gain and loss analysis. Background Art

[0002] With the rapid increase in my country's urbanization rate, the demand for the development of the construction industry is also increasing, which is bound to bring about a large amount of energy consumption, posing a severe challenge to the energy conservation, emission reduction and low-carbon development of the construction industry.

[0003] During the architectural design phase, selecting and determining appropriate design strategies is a key directional issue for achieving green, low-energy, and even zero-carbon goals. Currently, widely used approaches for selecting and determining energy-saving design strategies include Olgyay's bioclimatic diagram method, Givoni's "climate design" approach, which combines temperature and humidity charts, and Mahoney's list method. Olgyay proposed a method for designing buildings based on human thermal comfort and outdoor climate conditions. This analytical approach was graphically represented, proposing various design elements, such as building form, orientation, and the location and size of openings, to compensate for adverse outdoor conditions. However, its greatest limitation is that this analysis of human thermal comfort is based on outdoor meteorological parameters and is therefore applicable to rooms with similar indoor and outdoor climate conditions. Givoni's method, however, develops Olgyay's "bioclimatic design method," by displaying the applicable range of nighttime ventilation, shading, and other measures on a temperature and humidity chart, creating a "building climate design analysis chart" that clearly identifies potential energy-saving measures. The Mahoney list method adopts the effective temperature method when considering human thermal comfort, takes into account the adaptability of people to the climate in different climate zones, and establishes the relationship between climate indicators and specific building measures.

[0004] These methods can provide design recommendations for passive energy-saving design strategies, but their application still presents certain challenges. First, while designers can propose energy-saving design strategies, they often lack year-round considerations, making it easy to focus on one aspect and neglect another. Design strategies tailored to a particular season can easily deteriorate the environment in other seasons, leading to increased overall energy consumption. For example, adding a sunroom in winter could increase air conditioning energy consumption in the summer, failing to achieve the goal of reducing building energy consumption.

[0005] Secondly, although designers can predict the energy-saving effects of design strategies using software tools, they often do not understand the reasons for the effects, cannot determine the priority of energy-saving strategies, and cannot optimize and improve the strategies in a targeted manner.

[0006] The "Code for Thermal Design of Civil Buildings" (GB50176-2016) proposes principles for thermal insulation, heat protection, moisture-proofing, thermal insulation of building envelopes, natural ventilation, and building shading. The "Energy-Saving Design Standard for Residential Buildings in Severely Cold and Cold Regions" (JGJ 26-2018) proposes corresponding energy-saving design measures based on the overall layout, shape coefficient, window-to-wall area ratio, and thermal performance parameters of the building envelope for residential buildings in severe cold and cold regions. This standard primarily focuses on reducing winter heat loss and emphasizes insulation of building envelopes. The "Energy-Saving Design Standard for Residential Buildings in Hot Summer and Cold Winter Regions" (JGJ 134-2010) focuses primarily on summer insulation. The "General Code for Energy Saving and Renewable Energy Utilization in Buildings" (GB55015-2021) proposes that building energy conservation should prioritize passive energy-saving measures while increasing the proportion of renewable energy. However, these energy-saving standards rarely address the evaluation of energy-saving effects throughout the year and the reasons for these effects.

[0007] Therefore, how to conduct an in-depth analysis of the causes of energy consumption and propose appropriate design strategies based on a year-round perspective is a pressing issue in current building energy-saving design. This paper attempts to analyze the heat gain and loss of buildings throughout the year, obtain the levels of heat gain and loss in each building in different seasons, and propose energy-saving measures to address the main contradictions. Furthermore, using a comprehensive annual evaluation index, it proposes a design strategy combination based on maximizing annual benefits, as well as annual comprehensive benefit indicators under different combinations, in order to provide architectural designers with a convenient and powerful analysis tool, contributing to building energy conservation and even zero-carbon building. Summary of the Invention

[0008] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a building energy-saving design method based on annual heat gain and loss analysis to solve the problems of the existing technology.

[0009] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0010] A building energy-saving design method based on annual heat gain and loss analysis includes the following steps:

[0011] Step 1: Determine the building's geometric information, structural information, and thermal physical parameters of the materials; determine the building's indoor and outdoor calculation parameters, meteorological parameters, and information such as indoor personnel, equipment, and lighting power density.

[0012] Step 2: Calculate and count the heat gain and loss of the building as a whole and each room in each season. The heat gain and heat loss statistical analysis items mainly include:

[0013] a. Heat gain from solar radiation through glass windows;

[0014] b. The temperature difference between indoor and outdoor air causes heat transfer in the enclosure structure;

[0015] c. Heat gain (loss) due to ventilation (infiltration);

[0016] d. Heat gain (loss) by personnel, equipment, and lighting;

[0017] e. The equipment system supplies heat;

[0018] Step 3: Sort the heat gain and loss items in step 2 according to different seasons to obtain the main heat gain and heat loss items of each room and the building as a whole.

[0019] Step 4: Based on the ranking results, propose targeted energy-saving design strategies at the building level and room level, and determine the priority of these energy-saving design strategies.

[0020] Step 5: Examine the comprehensive benefits of a certain season’s energy-saving design strategy throughout the year. For example, the energy-saving amount of the winter energy-saving design strategy in winter is q1, and in other seasons it is q2, and the comprehensive benefits of the year are Δq w =q1-q2, if Δq w If Δq is less than zero, return to step 1 to redesign the building design and adjust the energy-saving design strategy. w If the value is greater than zero, the strategy is determined to be a year-round design strategy. The method for determining the comprehensive benefits of energy-saving design strategies in summer and other seasons is the same as that in winter.

[0021] Step 6: For multiple annual comprehensive income Δq w All of them are positive energy-saving design strategies. Combination design is carried out for single strategies. The annual energy consumption and energy-saving rate of the building under different combinations are calculated to determine the combination working condition with the greatest energy-saving potential and the energy-saving rate level under this working condition.

[0022] Preferably, it is characterized in that:

[0023] In step 2, the heat gain and heat loss items in winter and summer include:

[0024] Heat gain from solar radiation through glass windows:

[0025] Q s =C clC C z D Jmax #(1)

[0026] C z =C w C n C s #(2)

[0027] Among them, Q sis the heat gain from solar radiation through the glass window, C clC C is the heating and cooling load coefficient of solar radiation through standard unshaded glass; z is the comprehensive shading coefficient of the exterior window; C w is the external shading correction coefficient; C n is the internal shading correction coefficient; C s is the glass correction factor; D Jmax It is the maximum value of solar heat gain factor.

[0028] The temperature difference between indoor and outdoor air causes heat transfer in the building envelope:

[0029] Q n =A n K n (t2-t 2，n )#(3)

[0030] Where n is the number of the enclosure structure; Q n A is the amount of heat gained or lost by the building due to the heat transfer from the nth envelope structure at each hour; n is the area of ​​the nth enclosure structure; K n is the heat transfer coefficient of the nth surface enclosure structure; t2 is the instantaneous value of the enclosure structure calculation temperature; t 2，n Design temperature for the room.

[0031] Heat gain (loss) caused by ventilation:

[0032] Q w =0.278V w ρc#(4)

[0033] Among them, V w In winter, it is the total amount of air that seeps into the gaps between doors and windows; V w In summer, it is the total amount of air entering through open doors and windows; ρ is the air density at outdoor temperature, and c is the constant pressure specific heat of air.

[0034] Heat gain (loss) from personnel, equipment, and lighting:

[0035]

[0036]

[0037]

[0038] Among them, Q p Heat generated by human metabolism, Ccl rt is the human cooling load coefficient, Φ is the cluster coefficient, Q rt is the heat dissipation of the human body, which can be obtained by consulting the Code for Design of Heating, Ventilation and Air Conditioning for Civil Buildings (GB 50736-2012).l Heat generated by household appliances lighting, C clzm is the lighting cooling load coefficient, C zm is the lighting correction factor, Q zm is the heat dissipated by lighting, Q e is the heat generated by the equipment, C clsb is the equipment cooling load coefficient, C sb is the equipment correction factor, Q sb Dissipate heat for the device.

[0039] Preferably, in step 5, the annual comprehensive income of a certain season, taking winter and summer as an example, is calculated as follows:

[0040] The annual comprehensive benefit Δq of the winter seasonal energy design strategy w :

[0041] Δq w =q1-q2#(8)

[0042] The annual comprehensive benefit Δq of the summer seasonal energy design strategy s :

[0043] Δq s =q3-q4#(9)

[0044] Only the methods for winter and summer are listed here. If there is overheating (coldness) problem in spring and autumn, the design strategy and the determination of the comprehensive benefits for the whole year should refer to formulas (8) and (9).

[0045] Among them, q1 is the winter energy consumption reduced by the winter seasonal energy-saving design strategy, q2 is the energy consumption increased by the winter seasonal energy-saving design strategy in other seasons of the year, q3 is the summer energy consumption reduced by the summer seasonal energy-saving design strategy, and q4 is the building energy consumption increased by the summer seasonal energy-saving design strategy in other seasons of the year.

[0046] Preferably, the annual energy saving rate of the building in step 6 is:

[0047]

[0048] Among them, J is the annual energy saving rate of the building, t D,out is the average daily outdoor air temperature throughout the year, t D,in The energy saving rate calculation formula is derived from the patent "A Method for Calculating Building Energy Saving Rate" (CN201510072207.4) and can more accurately reflect the energy saving effect throughout the year.

[0049] Compared with the prior art, the present invention has the following technical effects:

[0050] (1) The design method of the present invention takes into account the energy-saving effect of the energy-saving design strategy throughout the year, making the effect of the energy-saving design clearer and improving the existing energy-saving design evaluation system.

[0051] (2) The design method of the present invention finds the main heat gain and heat loss items by analyzing the heat gain and loss of the building in summer and winter, so as to propose energy-saving design strategies in a more targeted manner, so that the energy-saving design has a basis to rely on and solves the main contradictions.

[0052] (3) The design method of the present invention determines the energy-saving design strategy of the building and rooms with different orientations based on the calculation results of heat gain and loss, taking into account the differences in the outdoor thermal environment facing each room of the building, making the building energy-saving design more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a plan view of an embodiment of the present invention;

[0054] Figure 2 This is a schematic diagram of a heat gain project of a building envelope structure in summer according to an embodiment of the present invention;

[0055] Figure 3 This is a schematic diagram of heat gain of exterior windows of a building in different directions in summer according to an embodiment of the present invention;

[0056] Figure 4 This is a schematic diagram of a heat loss project of a building envelope structure in winter according to an embodiment of the present invention;

[0057] Figure 5 This is a schematic diagram of heat loss projects of exterior windows in different orientations in winter in an embodiment of the present invention;

[0058] Figure 6 It is a schematic diagram of the annual energy saving rate of a building under different working condition combinations according to an embodiment of the present invention.

[0059] The specific contents of the present invention are further explained in detail below with reference to the embodiments. DETAILED DESCRIPTION

[0060] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0061] Example:

[0062] The enclosing structures in this article include: west wall, north wall, east wall, south wall, west exterior window, north exterior window, east exterior window and south exterior window.

[0063] This embodiment takes a residential building in Turpan as an example to illustrate the specific application method of the present invention.

[0064] Build a building model, floor plan Figure 1 shown.

[0065] Step 1: Collect the basic information of the building model: net window glass area; area of ​​walls and windows in different orientations; roof area; heat transfer coefficients of windows, walls, and roof, as shown in Tables 1 and 2:

[0066] Table 1: Basic information of the building model

[0067]

[0068] Table 2: Area of ​​windows in different orientations

[0069]

[0070] Step 2: Calculate heat gain and loss for typical seasons. Here, we take winter and summer as examples. According to formulas (1) to (7), the heat gain and heat loss items are obtained and statistically analyzed.

[0071] First, the indoor heat gain and loss in summer are calculated and counted. The results are shown in Table 3. The main heat gain items are heat transfer of the enclosure structure caused by the temperature difference between indoor and outdoor. and the heat from the sun through the windows s , heat loss items have ventilation and lose heat Q w .

[0072] Table 3: Calculation and statistics of heat gain and loss in summer

[0073]

[0074] Table 4: Solar heat gain through windows of different orientations in summer

[0075]

[0076] Table 5: Calculation and statistics of heat gain of building envelopes with different orientations in summer

[0077]

[0078] Step 3 to Step 4: Based on the principle of reducing heat gain and increasing heat loss in summer, use formula (3) to calculate the heat transfer of the enclosure structure in different directions in summer. The calculation results are statistically analyzed, such as Figure 2 As shown in Table 5, Q5>Q1>Q3>Q2>Q4. The roof, west wall, east wall and north wall account for 88% of the total heat gain of the exterior wall. Priority should be given to taking insulation measures on the roof, west wall, east wall and north wall of the west-facing rooms (first bedroom and second bedroom);

[0079] from Figure 3As can be seen from Table 5, Q9>Q8>Q7>Q6, south windows, east windows and north windows account for 95% of the total external window heat gain. Insulation treatment can be taken for the windows facing south, east and north, which can reduce the heat transfer coefficient of the windows and reduce the amount of heat transferred through the windows.

[0080] According to formula (1), the amount of solar heat gain through windows of different orientations in summer can be calculated. As shown in Table 4, south windows and east windows account for 70% of the total solar heat gain of the building's exterior windows. Sunshade treatment can be taken for windows of these two orientations to reduce the amount of solar heat gain through the exterior windows.

[0081] As far as heat loss is concerned, night ventilation is a heat loss item, so night ventilation measures can be taken to reduce room temperature;

[0082] Step 2: Calculate and count the indoor heat gain and loss in winter. The results are shown in Table 6.

[0083] Table 6: Calculation and statistics of heat gain and loss in winter

[0084]

[0085] Table 7: Calculation and statistics of heat loss of building envelopes in different orientations in winter

[0086]

[0087]

[0088] Step 3 to Step 4: Sort the calculation results of winter heat gain and loss in Table 6, Q s >Q p >Q l >Q e ,

[0089] Based on the principle of increasing heat gain and reducing heat loss in winter, passive solar energy utilization is preferred. Because my country is located in the northern hemisphere, with stronger southerly solar radiation, adding additional sunrooms to the south, such as those in front of the second bedroom and living room, can be considered. These additional sunrooms are equipped with heat collectors and thermal storage devices to utilize solar energy and increase heat gain.

[0090] From the perspective of reducing heat loss in winter, the heat gain and loss of the enclosure structure in different directions in winter are calculated according to formula (3). from Figure 4 As can be seen from Table 7, Q5>Q1>Q2>Q3>Q4, the roof, west wall, north wall and east wall account for 84% of the total heat loss of the wall. Insulation measures can be taken for the roof, west wall, north wall and east wall of the west-facing rooms (first bedroom and second bedroom);

[0091] from Figure 5 As can be seen from Table 7, among the heat lost by the exterior windows in different directions, Q9>Q8>Q7>Q6, and the south windows, east windows and north windows account for 93% of the lost heat. Insulation measures can be added to the windows in these three directions to reduce the heat transfer coefficient of the windows and reduce the heat loss of the windows.

[0092] The energy-saving design strategies proposed for both winter and summer are as follows: ① Add a sunroom to the south (with sunshade); ② Ventilate the room at night; ③ Take thermal insulation measures for the roof, west wall, north wall and east wall of the west-facing rooms (first bedroom and second bedroom); ④ Take thermal insulation measures for the south, north and east exterior windows.

[0093] Step 5: Take the winter energy-saving design measures of adding a south-facing sunroom to the residential building as an example. The winter energy-saving design strategy will increase summer energy consumption. The additional sunroom is a raised type, with a depth of 1.5m, the same height and width as the building, and the internal window construction method is the same as the original building. The increase in heat gain per unit building area in winter q1 is 16.33KWh, and the increase in heat gain per unit building area in summer q2 is 26.46KWh, Δq w =q1-q2<0.

[0094] Adjust the design of the residential building model, perform shading on the additional sunroom, and recalculate Δq w , then Δq w If it is greater than 0, it means that the measure is feasible throughout the year. According to this method, the annual energy saving rate of each individual strategy can be determined, as shown in Table 8 below.

[0095] Table 8: Annual energy saving rate of single energy-saving design strategy

[0096]

[0097] The single energy-saving design strategy proposed above cannot meet the needs of different seasons simultaneously, and a combination of multiple energy-saving design strategies must be considered. Table 9 lists several combined operating conditions and their energy-saving rates. Under year-round operating conditions, the energy-saving rates are ranked from highest to lowest: 5 > 4 > 3 > 2 > 1, indicating that operating condition 5, when used with a sunroom and sunshades, has the highest year-round energy-saving rate. The increase from operating condition 1 to operating condition 2 is the largest, indicating that adding a sunroom (with sunshades) and nighttime ventilation are the most effective energy-saving measures.

[0098] Table 9: Annual energy saving rate of buildings under different working conditions

[0099]

[0100]

[0101] By comparing the energy-saving rates of the energy-saving strategies proposed by this method and other related methods, it can be found that, regardless of working condition 2 or working condition 5, the energy-saving rate corresponding to the strategy proposed by the present invention is further improved compared with the energy-saving rates of other methods.

[0102] Table 10: Comparison of different building climate analysis methods and this method

[0103]

Claims

1. A building energy-saving design method based on annual heat gain and loss analysis, characterized in that: The steps include: Step 1: Determine the building's geometric information, structural information, and thermal properties of materials; determine the building's indoor and outdoor calculation parameters, meteorological parameters, and indoor personnel, equipment, and lighting power density; Step 2: Calculate and count the heat gain and loss of the building as a whole and each room in each season throughout the year. The heat gain and heat loss statistical analysis items mainly include: a. Heat gain from solar radiation through glass windows; b. The temperature difference between indoor and outdoor air causes heat transfer in the enclosure structure; c. Heat gain / loss due to ventilation / infiltration; d. Heat gain / loss from personnel, equipment, and lighting; e. The equipment system supplies heat; Step 3: Sort the heat gain and loss items in step 2 according to different seasons to obtain the main heat gain and heat loss items of each room and the building as a whole; Step 4: Based on the ranking results, propose targeted energy-saving design strategies at the building level and room level, and determine the priority of these energy-saving design strategies; Step 5: Examine the comprehensive benefits of a certain season’s energy-saving design strategy throughout the year. The energy-saving amount of the winter energy-saving design strategy in winter is q1, and in other seasons it is q2. The comprehensive benefits of the year are Δq w =q1-q2, if Δq w If Δq is less than zero, return to step 1 to redesign the building design and adjust the energy-saving design strategy. w If it is greater than zero, the energy-saving design strategy is determined to be a design strategy that can be adopted throughout the year. The method for determining the comprehensive benefits of energy-saving design strategies in summer and other seasons is the same as that in winter. Among them, the comprehensive benefits of a season throughout the year, taking winter and summer as examples, are calculated as follows: The annual comprehensive benefit Δq of the winter seasonal energy design strategy w : Δq w =q1-q2# The annual comprehensive benefit Δq of the summer seasonal energy design strategy s : Δq s =q3-q4# Only the methods for winter and summer are listed here. If there are overheating / cold problems in spring and autumn, the design strategy and the determination of the comprehensive benefits for the whole year should refer to formulas (8) and (9); Among them, q1 is the winter energy consumption reduced by the winter seasonal energy-saving design strategy, q2 is the energy consumption increased in other seasons of the year by the winter seasonal energy-saving design strategy, q3 is the summer energy consumption reduced by the summer seasonal energy-saving design strategy, and q4 is the building energy consumption increased in other seasons of the year by the summer seasonal energy-saving design strategy; Step 6: For multiple annual comprehensive income Δq w All are positive energy-saving design strategies. Combined design of individual strategies is performed to calculate the annual energy consumption and energy-saving rate of the building under different combinations. The combined working condition with the greatest energy-saving potential and the energy-saving rate level under this condition are determined. The annual energy-saving rate of the building is: Among them, J is the annual energy saving rate of the building, t D,out is the average daily outdoor air temperature throughout the year, t D,in It is the average daily natural room temperature in the room.

2. The building energy-saving design method based on annual heat gain and loss analysis according to claim 1, characterized in that: In step 2, the heat gain and heat loss items in winter and summer include: Heat gain from solar radiation through glass windows: Q s =C clC C z D Jmax #(1) C z =C w C n C s #(2) Among them, Q s is the heat gain from solar radiation through the glass window, C clC C is the heating and cooling load coefficient of solar radiation through standard unshaded glass; z is the comprehensive shading coefficient of the exterior window; C w is the external shading correction coefficient; C n is the internal shading correction coefficient; C s is the glass correction factor; D Jmax is the maximum value of solar heat gain factor; The temperature difference between indoor and outdoor air causes heat transfer in the building envelope: Q n =A n K n (t2-t 2,n )#(3) Where n is the number of the enclosure structure; Q n A is the amount of heat gained or lost by the building due to the heat transfer from the nth envelope structure at each hour; n is the area of ​​the nth enclosure structure; K n is the heat transfer coefficient of the nth surface enclosure structure; t2 is the instantaneous value of the enclosure structure calculation temperature; t 2,n Design temperature for the room; Heat gain / loss due to ventilation: Q w =0.278V w ρc#(4) Among them, V w In winter, it is the total amount of air that seeps into the gaps between doors and windows; V w In summer, it is the total amount of air entering through open doors and windows; ρ is the air density at outdoor temperature, and c is the specific heat of air at constant pressure; Heat gain / loss from personnel, equipment, and lighting: Among them, Q p Heat generated by human metabolism, Ccl rt is the human cooling load coefficient, Φ is the cluster coefficient, Q rt is the heat dissipation of the human body, which can be obtained by consulting the "Design Code for Heating, Ventilation and Air Conditioning of Civil Buildings". l Heat generated by household appliances lighting, C clzm is the lighting cooling load coefficient, C zm is the lighting correction factor, Q zm is the heat dissipated by lighting, Q e is the heat generated by the equipment, C clsb is the equipment cooling load coefficient, C sb is the equipment correction factor, Q sb Dissipate heat for the device.

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