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The construction industry is one of the major energy-saving fields. It is necessary to define the target of energy conservation and emission reduction targets according to the future social and economic development needs and the energy characteristics of the construction industry. Based on the population development model, a top-down method was used to calculate the stock of building floor space in China in this study. A bottom-up model was established to the calculated energy consumption of China’s construction sector. Different scenarios of energy consumption in China’s construction field were constructed. The future total energy consumption of buildings under different scenarios was predicted. The results found that under the situation of ‘slow development of urbanization + strict control of per capita area’, by 2050, the total area of various types of buildings in China will reach 69.78 billion m2. Under the scenario of ‘medium energy conservation and emission reduction’, by 2030, the target of building energy consumption control in China is 102 million tce. In order to achieve the goal of energy saving and emission reduction in China, the national building stock should be restricted within 70 billion m2. This paper aims to provide reference for long-term planning of energy saving and emission reduction in China’s construction field.

Based on the analysis of building energy consumption data, this paper estimates the total energy consumption of buildings in China in the future. Around the control target of building energy consumption, we proposed a policy guarantee system from the aspects of laws and regulations, energy-saving supervise assessment system, working mechanism, energy conservation standards, energy conservation technology, and energy price policy.

Controlling the scale of civil buildings is of great significance for energy saving and emission reduction in the construction field. This paper analyzes and extracts the key index parameters for the calculation of various civil building areas, establishes a detailed calculation model of the total civil building area, and constructs three different scenarios to predict various civil building areas in China from 2020 to 2060. Under the three scenarios, the total amount of civil buildings in China will reach a peak of 93.5, 84.6, and 76.3 billion m2 in 2040, 2035, and 2035, respectively. Under the constraints of energy consumption and carbon emission, this paper suggests that civil buildings develop according to the medium control scenario. In 2035, the urban per capita residential area will reach a peak of 42 m2, the urban residential area will reach 43 billion m2, the rural per capita residential area will reach the peak of 55 m2, the rural residential area will reach 20.6 billion m2, and the public building area will reach 21 billion m2. By 2060, the total area of civil buildings will drop to 76.5 billion m2, including 37.1 billion m2 of urban residential buildings, 18.5 billion m2 of rural residential buildings, and 20.9 billion m2 of public buildings.

We propose to search for millicharged particles in electron colliders operated with the center-of-mass energies at ${\cal O}$(1-10) GeV, which include Belle II, BESIII, BaBar, and also the proposed experiment STCF. We use the monophoton final state at electron colliders to probe the parameter space of millicharged particles, that is spanned by millicharge $\epsilon$ and mass $m$. We find that electron colliders have sensitivity to the previously unexplored parameter space for millicharged particles with MeV-GeV mass: $\epsilon \lesssim {\cal O}(10^{-1})$ for $0.5$ GeV $\lesssim m \lesssim 3.5$ GeV in BaBar, $\epsilon \lesssim {\cal O}(10^{-3})$ for $0.1$ GeV $\lesssim m \lesssim 1.5$ GeV in BESIII, $\epsilon \lesssim 10^{-3}-10^{-2}$ for $0.1$ GeV $\lesssim m \lesssim 4$ GeV in Belle II, and $\epsilon \lesssim {\cal O}(10^{-4})$ for $1$ MeV $\lesssim m \lesssim 1$ GeV in STCF., Comment: 8 pages, 9 figures; v2: journal version

We present a dark matter model to explain the excess events in the electron recoil data recently reported by the Xenon1T experiment. In our model, dark matter annihilates into a pair of on-shell particles , which subsequently decay into the final state; interacts with electrons to generate the observed excess events. Because of the mass hierarchy, the velocity of can be rather large and can have an extended distribution, providing a good fit to the electron recoil energy spectrum. We estimate the flux of from dark matter annihilations in the galaxy and further determine the interaction cross section, which is sizable but sufficiently small to allow to penetrate the rocks to reach the underground labs.

A classified energy consumption statistics method is established to analyze and predict the future energy consumption of heating in northern China. Firstly, according to the energy intensity and proportion of central heating and decentralized heating, combined with the building area of cities and towns in northern provinces, the heating energy consumption in 2018~2035 is predicted. Then the energy saving potential of heating is analyzed by the scenario assumption. The results show that controlling energy consumption intensity has obvious energy saving effect on heating in northern towns of China. If the intensity and proportion of heating energy consumption are regulated, the peak of total heating energy consumption in the northern region will appear in 2030, reaching 265 million tce.