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The purpose of this study is to regard winter heating as a quasi-natural experiment to identify the possible causal effects of winter heating on population mobility. However, there are scant research studies examining the effect of atmospheric quality on population mobility. There also exists some relevant research studies on the relationship between population mobility and environmental degradation (Lu et al., 2018; Reis et al., 2018; Shen et al., 2018), and these studies exist still some deficiencies.

The notorious atmospheric quality problems caused by coal-fired heating in winter of northern China have an aroused widespread concern. However, the quantitative study on the effects on population mobility of winter heating is still rare. In this study, the authors regard the winter heating as a quasi-natural experiment, based on the of daily panel data of 58 cities of Tencent location Big Data in China from August 13 to December 30 in 2016 and August 16 to December 30 in 2017, and examine the impacts of winter heating on population mobility by utilizing a regression discontinuity method.

The findings are as follows, in general, winter heating significantly aggravates regional population mobility, but the impacts on population mobility among different cities are heterogeneous. Specifically, the effects of winter heating on population mobility is greater for cities with relatively good air quality, and the effects is also more obvious for big and medium-sized cities than that in small cities. In addition, different robustness tests, including continuity test, different bandwidth tests and alternative empirical model, are adopted to ensure the reliability of the conclusion. Finally, the authors put forward corresponding policy suggestions from the three dimensions of government, enterprises and residents.

First, regarding winter heating as a quasi-natural experiment, a regression discontinuity design method is introduced to investigate the relationship between winter heating and population mobility, which is helpful to avoid the estimation error caused by endogeneity. Second, the authors use the passenger travel “big data” based on the website of Tencent Location Big Data, which can effectively capture the daily characteristics of China's population mobility. Third, this study discusses the population mobility from the perspective of winter heating and researches population mobility before and after winter heating, which is helpful in enriching the research on population mobility.

Currently, China is the largest coal producer and consumer in the world. Underground mining is the main practice. In the process of deep mining, large amounts of low-temperature waste heat are available such as in the mine return air (MRA), mine water (MW), bathing waste water (BWW), etc. Without recycling, the low-temperature waste heat is discharged directly into the atmosphere or into the drainage system. The temperature range of the MRA is about 15-25°C, the relative humidity (RH) of the MRA is above 90 per cent, the temperature range of MW is about 18-20°C and the temperature of the BWW is about 30°C. All of the above parameters are relatively stable throughout the year, and thus MRA, MW and BWW are proper low-temperature heat sources for water source heat pump (WSHP) systems. The study aims to introduce the schemes for recycling the different waste heat sources and the relevant key equipment and technology of each waste heat recycle system; analyze the heat recovery performances of the MRA heat recovery technology; and compare the economies between the MRA heat recovery system and the traditional system.

Based on the WSHP system, heat and mass transfer efficiencies were calculated and analyzed, the outlet air velocity diffusion of the heat and mass transfer units and the parameters including air flow rate, the MRA’s dry bulb temperatures and wet bulb temperatures at inlet and outlet of MRA heat exchanger were tested. Then, it was assessed whether this system can be applied to an actual construction. An actual reconstructive project of MRA heat recovery system is taken as an example, where the cost-saving effects of heat recovery of mine waste heat sources system are analyzed.

Analysis of field test reveals that when heat transfer is stable, heat transfer capacity can be achieved: 957.6 kW in summer, 681 kW in winter and a large amount of heat was recycled. In an economic analysis, by comparing initial investment and 10 years’ operation cost with the traditional boiler and central air conditioning system, the results show that although the MRA system’s initial investment is high, this system can save CNY 6.26m in 10 years.

MRA has a large amount of air volume and temperature that is constant throughout the year, and hence is a good low-temperature heat source for the WSHP system. It can replace boiler heating in winter and central air conditioning refrigeration in summer. The study reveals that this technology is feasible, and has good prospects for development.

Promoting clean heating in rural areas is crucial for achieving a low-carbon transition of energy consumption and China's dual-carbon target. The study aims to consider the energy stacking behavior in heating energy use, reveals the determinants that affect household cleaner heating choices under the winter clean heating plan (WCHP), and proposes policy recommendations for the sustainable promotion of clean heating.

With unique rural household survey data covering the clean heating pilot regions in northern China in 2020, this study estimates the relationship between driving factors and heating energy choices through binary and multivariate probit models.

The regression estimates show that the main drivers of heating energy choices include household income per capita, education level of household head, knowledge of the WCHP, access to heating subsidies and perception of indoor air pollution. There is energy stacking behavior in rural household heating energy use. Household decisions to adopt electricity or clean coal heating are correlated with firewood or soft coal use.

This study is one of the few to investigate the heating energy use of rural households by allowing for the adoption of multiple energy types. Combined with a unique microsurvey dataset, it could provide rich information for formulating proper energy transition planning. The findings also shed light on the importance of heating subsidies, households' knowledge of WCHP and awareness of environmental health in choosing clean heating energy, which has not been fully valued in related research.

Climate change reports from New Zealand claim that climate change will impact some cities such as Auckland from a heating-dominated to a cooling-dominated climate. The benefits and risks of climate change on buildings' thermal performance are still unknown. This paper examines the impacts of climate change on the energy performance of residential buildings in New Zealand and provides insight into changes in trends in energy consumption by quantifying the impacts of climate change.

The present paper used a downscaling method to generate weather data for three locations in New Zealand: Auckland, Wellington and Christchurch. The weather data sets were applied to the energy simulation of a residential case study as a reference building using a validated building energy analysis tool (EnergyPlus).

The result indicated that in Wellington and Christchurch, heating would be the major thermal load of residential buildings, while in Auckland, the main thermal load will change from heating to cooling in future years. The revised R-values for the building code will affect the pattern of dominant heating and cooling demands in buildings in Auckland in the future, while in Wellington and Christchurch, the heating load will be higher than the cooling load.

The findings of this study gave a broader insight into the risks and opportunities of climate change for the thermal performance of buildings. The results established the significance of considering climate change in energy performance analysis to inform the appropriate building codes for the design of residential buildings to avoid future costly changes to buildings.

The current depletion of fossil fuels and environmental degradation are requiring greater energy efficiency in buildings, particularly in the residential sector. However, environmental improvement actions for dwellings are usually based on general considerations, without identifying the most appropriate measurements to be taken in each case, or reviewing their application with stakeholders. This article puts forward a strategy to propose effective and feasible modifications in the design or refurbishment of single-family homes to reduce energy use while maintaining indoor comfort. The improvements proposed are based on dynamic energy simulations of individual models adapted to local realities that can be carried out by regular professionals. The process includes the review of studies and information on the geographic area, and compilation of the constructive features and occupancy data of each house to create a proper energy behaviour model. Possible improvements to the building are then simulated separately in each model and the results recorded. Subsequently, a budgetary analysis of these alternatives according to construction costs and financial projections is carried out in order to identify retrofit packages and consult the opinions of residents and builders. The application of this strategy is demonstrated in the study of several houses in Concepción, Chile, where different sets of measures have been identified to achieve high reductions in energy demand while having low cost and being highly appreciated by the participants. This provides a methodology for developing and validating effective solutions for the environmental improvement of existing dwellings and new housing projects.

New Zealand’s historical housing stock comprises largely single-storey detached houses, characterised by poor winter comfort with high air infiltration. Challenges with affordability and land use are shifting New Zealand’s housing stock towards double-storey, conjoined medium-density housing (MDH). Reduced external surfaces in this typology should reduce winter heat loss and infiltration, improving winter comfort and health. New concerns arise, however, regarding summertime overheating and poor indoor air quality.

A field study was undertaken where temperature, humidity, airtightness, particulate matter (PM) and total volatile organic compounds (TVOC) were measured in two unoccupied, newly built double-storey, conjoined houses, for several weeks over summer.

The reduced surface area of this typology did not reduce infiltration and demonstrated significant periods of overheating. Internal PM concentrations generally exceeded outdoor concentrations but did not exceed annual average outdoor PM10 guidelines of 20 µg m-3. Infiltration factors (Finf) were closer to more traditional houses. TVOC readings varied widely, but frequently exceeded international guidelines.

The small sample limits the applications of conclusions more widely. Recommendations to investigate a wider sample in different locations with more detailed VOC analysis over all seasons are made.

Improvements to internal environments cannot be guaranteed by housing typology changes alone and must still involve thoughtful environmental design.

Housing typology changes may not improve internal living environments.

A move to the new MDH typology may not achieve expectations of airtightness and thermal improvement. New challenges arise from significant overheating and high TVOC levels, which may lead to new negative health effects.

The purpose of this paper is to describe a programme of research into an innovative approach to whole‐house ventilation with heat reclaim. In order to save energy, houses are now required to be constructed to a high level of air tightness. This poses potential problems of indoor air quality, condensation and mould growth, with implications for human health. Adequate and controlled ventilation is a necessity, and in Europe the adoption of mechanical systems incorporating heat reclaim has become the preferred technology. The relatively mild climate of the UK undermines the efficiency of these fan‐driven solutions. The programme of research has been to test the viability of an engineered system of natural ventilation for use in temperate regions.

The system works by the combination of “supply air” windows and passive stacks. The windows have an air path for incoming ventilation that passes between panes of glass, the pressure drop across the windows to induce the air flow through them is provided by the passive stacks in kitchens and bathrooms. Passive stacks are an alternative to the use of extract fans; they have been included in the building regulations since their efficacy was proven by research carried out at the Building Research Establishment in the 1980s. “Supply air” windows are manufactured in Finland, and have also been researched in Canada. The research described in this paper is the first to combine “supply air” windows and passive stacks to form a system that is completely natural and operates without the use of electricity. It has been carried out over the course of a number of projects. Beginning with laboratory studies that established the design dimensions for the windows, followed by test cell measurements, and then installation in real buildings monitored, both empty and occupied. Each stage was validated in relation to simulation models.

It was demonstrated that window U‐values of down to 0.6 W/m²/°C can be achieved. It has been demonstrated in real building applications that a reduction in overall household heating consumption of 20 per cent is attained in dwellings where the system has been installed. User approval, which was the focus of the later projects carried out in Norwich, has also been high.

The windows have no special installation requirements and passive stacks are a catalogue component. The windows are designed as two separate sashes that are locked together by catches that can be undone to clean the space between the panes. The system is an alternative to mechanical ventilation heat reclaim systems, it is a simple low maintenance, low‐cost method that offers good indoor air quality as well as energy advantages, which has been shown to be particularly suited to the typical winter climate conditions in the UK.

The need to design buildings with due consideration for bioclimatic and passive design is central to promoting sustainability in the built environment from an energy perspective. Indeed, the energy and atmosphere considerations in building design, construction and operation have received the highest consideration in green building frameworks such as LEED and BREEAM to promote SDG 9: Industry, Innovation and Infrastructure and SDG 11: Sustainable Cities and Communities and contributing directly to support SDG 13: Climate Action. The research literature is rich of findings on the efficacy of passive measures in different climate contexts, but given that these measures are highly dependent on the prevailing weather conditions, which is constantly in evolution, disturbed by the climate change phenomenon, there is pressing need to be able to accurately predict such changes in the short (to the minute) and medium (to the hour and day) terms, where AI algorithms can be effectively applied. The dynamics of the weather patterns over seasons, but more crucially over a given season means that optimum response of building envelope elements, specifically through the passive elements, can be reaped if these passive measures can be adapted according to the ambient weather conditions. The use of representative mechatronics systems to intelligently control certain passive measures is presented, together with the potential use of artificial intelligence (AI) algorithms to capture the complex building physics involved to predict the expected effect of weather conditions on the indoor environmental conditions.

The Middle Eastern terrain is expected to encounter unprecedented climatic conditions before the turn of the next century (circa. 80 years), emanating from extreme heat waves that exceed the critical threshold of habitable conditions. This threatens to cause a significant challenge that is exacerbated by a gap between the supply and demand of affordable energy. Therefore, the purpose of this study is to investigate the potential of utilising nearly zero-energy buildings (nZEB) to improve the performance of residential buildings in Iraq and the Middle East.

This study uses Iraq as a case-study because of the breadth of climatic conditions experienced across its wide-reaching territory and also because of the recent critical infrastructural challenges following the geo-political crisis. Three virtual buildings were simulated for Baghdad, Mosul and Basra cities to narrow the confines of the region to achieve nZEB under current and future climatic weather scenarios.

The findings showed that in all three cases studies, the buildings located within the three climatic regions in Iraq could achieve both significant annual energy reductions as well as nZEB standards which could range from 41 per cent to 87 per cent for current climatic conditions and 40 per cent to 84 per cent by 2080. An analysis has also been carried out for the three case-study cities which revealed significant operational-cost savings achievable through nZEB buildings.

There are currently limited studies that investigate such positive potential for nZEB strategies under the current and predicted future climatic scenarios in the Middle East.

In order to verify the feasibility of different techniques, this chapter further studies the adaptability of two massive straw biomass applications in rural areas in China.

The methods of assessing biomass power generation project with Life Cycle Assessment (LCA), survey and field test of one biogas station, and game-theoretic analysis are adopted.

The following conclusions can be drawn: The air pollution costs account for more than 60% of the total environmental cost, followed by depreciation expense and maintenance fee of 18%, compared to that of biomass power generation at 0.01711 CNY/kWh. The adopted greenhouse sunlight technology of Solar Biogas Plant in Xuzhou, China, raises the inside average temperature by 11.0 °C higher than outside and keeps the pool temperature above 16 °C in winter, ensuring a gas productivity of biogas project in winter up to 0.5–0.7 m³/m³ by volume. This chapter also analyzes the information cost incurred by asymmetric information in biomass power generation via game theory method and illustrates the information structure with game results. It provides not only a foundation for the policy research in promoting straw power generation but also theoretical framework to solve the problem of straw collection.

These studies will propose solutions to relevant problems arisen in the running process.

These studies are all based on real cases, field research, and appropriate theoretical analyses, so, they can reduce the relevant costs and promote the application of relevant technologies.