| The construction industry at home and abroad occupies an important place in the carbon emissions of the whole society.The global construction industry produces 39%of the greenhouse gases generated by the whole industry,and in China,the figure is25%.In the severe global warming situation,China proposes to complete the carbon peak in 2030 and the carbon neutral goal in 2060,striving to reduce the carbon emissions of various industries.At present,there are various ways to achieve energy saving and emission reduction in the building field.Buildings can effectively restrain building energy consumption by conducting heat exchange between the internal and external environment through the envelope and adopting energy-saving materials to reduce their thermal parameters;near-zero energy buildings are a form of building to achieve a low-energy and high-comfort building indoor environment in the future and have a broad development potential.Many studies have been conducted on the two directions of building envelope energy efficiency and the development of near-zero energy buildings,but most of them take a single building as an example to prove its effect of energy saving,lacking the analysis of the upper limit of energy saving when the building is applied to the whole region.If these two ways of building energy saving are combined with the energy consumption peak target in Carbon Peak to explore its energy saving potential,it may provide an effective reference for the road to Carbon Peak in the building field.Based on the above description,this paper conducts research and analysis.Firstly,residential and commercial buildings in towns and cities in sub-tropical climate zones,where commercial buildings are divided into hotels,shopping malls and office buildings,are used to derive the year-by-year percentage of floor area renewable energy before the peak carbon time point using high-precision fitted curve prediction and gray model prediction methods.Secondly,the control variable method was used to reduce the thermal parameters of each building envelope type year by year in the program year with other conditions of the typical building unchanged,and the month-by-month and year-by-year energy consumption values per unit area of the typical building were simulated and calculated.Again,an energy consumption calculation model is established to derive the energy consumption values of the buildings in the whole region before the implementation of the retrofit program and the energy consumption values of the buildings after the implementation of the energy-saving measures for the retrofit of the thermal parameters of the existing building envelope and the construction of near-zero energy buildings.Finally,the peak energy consumption points of different types of buildings and all buildings in each province before the carbon peak time point are observed to determine whether the peak energy consumption is reached or not,and if it is reached,it indicates that buildings in sub-tropical climate zones have energy saving potential for energy consumption peak.The specific conclusions drawn from the above research steps are as follows.(1)The residential and commercial building area in cities and towns in sub-tropical climate zones increases year by year,but the growth rate decreases year by year.The former is 5.833 billion square meters,with a growth rate of 1.74%year-on-year,while the latter is 724 million square meters and 1.94%,respectively,meeting the peak requirements of urban residential building area in the medium scenario by 2042 and public building area in the medium scenario by 2040.(2)The proportion of renewable energy generation increases year by year except2011,from 31.1%in 2019 to 41.2%in 2030,which meets the requirements of Guangdong’s 14th Five-Year Plan of striving to reach 40%of renewable energy generation in 2035.(3)Between 2020 and 2030,the energy consumption per unit area of buildings will decrease year by year,with the largest decreases in 2021 and 2022,due to the impact of the implementation of the General Specification for Energy Conservation and Renewable Energy Use in Buildings in 2022,which will require a significant reduction in the thermal parameters of new building envelopes between 2020 and 2022.(4)The total energy consumption of urban residential and commercial buildings before the adoption of retrofit measures increases year by year except in 2021.By 2030,the figures are 1.0652602×10~5 million k Wh and 5.024828×10~4 million k Wh,with growth rates of 0.15%and 0.49%respectively over the previous year,and the total building energy consumption grows by 0.26%over the previous year,indicating that retrofitting measures need to be adopted to reach the energy consumption peak target.(5)After the construction of near-zero energy buildings,the energy consumption savings will rise year by year,and by 2030,the energy consumption savings of urban residential buildings and commercial buildings will be 240.6541 million k Wh and138.0731 million k Wh,respectively.at the same time,a 10%proportion of existing residential building area and a 100%proportion of existing commercial building area will be retrofitted in time batches of envelope structure to reach the parameter level of new buildings in that year.(6)By 2030,the total energy consumption of residential buildings after adopting retrofitting measures is 1.0526949×10~5 million k Wh,with a growth rate of 0.04‰over the previous year,which is approximately regarded as reaching the peak energy consumption target;while commercial buildings reach the target in 2029,with energy consumption of 4.855642×10~4 million k Wh in that year,and the energy consumption value from 2030 onwards shows a decreasing trend,with a change of-0.06%from the previous year.The total energy consumption of buildings reaches the peak in 2029,and the energy consumption from 2030 onwards is decreasing,with a change of-0.02%from the previous year,indicating that urban buildings in sub-tropical climate zones have the energy saving potential to reach the peak energy consumption. |
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