Da Yan

Tsinghua University | TH ·  School of Architecture

Simulating and predicting urban patterns enables evidence-based decision-making for urban planners. Given limited resources, understanding how to improve urban residential quality and rationally plan the distribution of different quality levels warrants further study. Using cellular automata (CA) and agent-based modules, this study proposes a multi...

Lighting energy consumption accounts for a considerable proportion of the total electricity consumption of a building; therefore, the lighting system of a building has great potential for energy saving. With the development of technology, intelligent lighting control systems are widely used in buildings and have good energy-saving effects. Previous...

Occupancy information, especially the number of occupants, can effectively guide the operation of building systems. Capturing real-time and accurate occupancy information is critical. Passive infrared (PIR) sensors and smart meters have been deployed extensively. To improve the occupancy detection accuracy, this study proposes an innovative occupan...

The integration of renewable energy into cityscapes is becoming increasingly crucial to climate change since city is main sector of energy consumption. This research estimated daily changes in rooftop photovoltaic (PV) output and building energy demand across different seasons using 3D building data from 32 global cities, investigated the inherent...

The appropriate design of urban ventilation corridors (VCs) can improve the urban thermal environment, thereby reducing urban energy consumption and promoting sustainable urban development. However, existing research lacks a comprehensive grasp of the characteristics of VCs from multiple dimensions and quantitative analysis of its cooling effect. W...

Passive radiative cooling materials (RCM) can cool surfaces by radiating heat to outer space via long-wave radiation. In simulation application, co-simulation of the thermal process between RCMs and building structures is generally required; however, the high computing time cost and low integration level have hindered the integrated whole-building...

Building thermal process simulation is an effective technique for quantitatively analyzing building energy consumption. The finite difference method is commonly used for structuring heat transfer equations due to its generality. However, the state-space method is preferred in BPS tools due to its computational efficiency. As building simulation ana...

Building energy simulation analysis plays an important supporting role in the conservation of building energy. Since the early 1980s, researchers have focused on the development and validation of building energy modeling programs (BEMPs) and have basically formed a set of systematic validation methods for BEMPs, mainly including analytical, compara...

Energy consumption in residential buildings accounts for a large portion of global energy use. Understanding residential building load characteristics is important in both the design and technical suitability analysis of residential air conditioning systems in terms of energy efficiency and carbon reduction. However, most current research mainly fo...

Building energy modeling (BEM) has become increasingly used in building energy conservation research. Prototype building models are developed to represent the typical urban building characteristics of a specific building type, meteorological conditions, and construction year. This study included four residential buildings and 11 commercial building...

Among the sufficiency, efficiency, and renewable frameworks for reducing energy use and energy-related carbon emissions, Building Energy Sufficiency (BES) is gaining attention from policy makers and engineers. Despite the significant role of the building sector in the success of national energy and climate plans, there is a lack of research on the...

Occupant control behavior is a key factor affecting the energy consumption of building air-conditioners (ACs). The operating behavior of ACs and their models in office buildings have been investigated extensively. However, although the thermal sensation of occupants is affected by their previous thermal experience, few researchers have attempted to...

Climate change will continuously impact building heating and cooling demands. Therefore, it is essential to characterise the varying future heating and cooling demands, which will help energy planning and avoid the lock-in effect of infrastructure. In this study, future meteorological data for building simulations were generated using global climat...

The outdoor climate condition is one of the deterministic factors influencing building energy consumption. Building performance simulation (BPS) tools usually adopt typical meteorological year (TMY) as the outdoor climate input. Despite that many scholars and institutes have developed TMY datasets, these datasets are usually based on distinct data...

Occupant behavior (OB) contributes significantly to uncertainties in the results of building performance simulation (BPS). However, a consensus regarding the appropriate level of detail (LoD) for OB modeling in BPS is yet to be reached. Hence, this study focuses on district cooling simulation applications. A systematic technical framework for deter...

Indoor temperature and relative humidity control in office buildings is crucial, which can affect thermal comfort, work efficiency, and even health of the occupants. In China, fan coil units (FCUs) are widely used as air-conditioning equipment in office buildings. Currently, conventional FCU control methods often ignore the impact of indoor relativ...

Assessing the urban-scale building photovoltaic (PV) potential is important for designing urban environments, retrofitting existing structures, or integrating PVs with grids. However, few studies have considered high-temporal-resolution simulations, the facade PV potential, and a comprehensive PV model simultaneously; thus, the overall accuracy of...

The excessive simplification of occupant behavior is considered as the most important factor that affects the uncertainty of building performance simulation, thus affects the reliability and generalizability of simulation-based design and forecast. In this paper, occupant behavior in air-conditioned office buildings of the Pearl River Delta (PRD) r...

Buildings are a major contributor to climate change, accounting for one third of global energy consumption and one quarter of CO2 emissions. However, comprehensive information is lacking for the development, evaluation and monitoring of mitigation policies. This paper discusses the remaining challenges in terms of reliability and consistency of the...

Radiative cooling materials (RCMs) possess the capability of passively transferring heat from surfaces to the outer space through the atmospheric window via long-wavelength radiation and cool the surfaces to below the ambient temperature, showing excellent potentials for building energy efficiency. To adequately embody this passive cooling effect,...

Occupancy patterns are key elements in improving our understanding of building energy usage and implementing demand-oriented strategies to reduce energy consumption. Occupancy pattern is changed over time driving by multiple factors, but there are lacks of research to reveal its temporal change. We analyzed occupancy pattern of residential building...

Model predictive control (MPC) has shown potential in improving building performance but is bottlenecked by the difficulty in constructing control-oriented models. The challenge lies in evaluating the sufficiency of the model and the data usage beforehand. This paper bridges the knowledge gaps in the interactions between data requirements, model qu...

Occupancy patterns in residential buildings and profiles with family information are essential for the energy system design and optimization, for the electricity demand responses and management of buildings, and for constructing household energy efficiency policies. To address the shortcomings of current research, this study conducted a national-wi...

Exposure to excessive ambient light at night (ALAN) has been proved to have a statistical association with human diseases. But current studies on ALAN exposure inequity have likely underestimated exposure levels due to the neglect of personal mobility. Based on mobile phone positioning big data and night-light satellite imagery, we conducted an emp...

With the increase in the energy consumption of air-conditioning (AC) systems in Chinese residential buildings, the realization of energy savings in AC systems has attracted increasing attention. The variable refrigerant flow (VRF) system is a common AC system for residential buildings in China. In most previous studies on VRF systems, onsite measur...

Thermal energy storage (TES) is an effective method for load shifting and demand response in buildings. Optimal TES control and management are essential to improve the performance of the cooling system. Most existing TES systems operate on a fixed schedule, which cannot take full advantage of its load shifting capability, and requires extensive inv...

Occupant's movement in buildings is one of the most essential factors that influence building energy consumption. Understanding the movement of occupants in buildings is crucial for building design and operations. The advances in virtual reality (VR), especially immersive virtual environments (IVEs), offer new and cost-effective alternatives for oc...

Urban building energy modeling (UBEM) is a promising tool to evaluate building energy consumption at high temporal-spatial resolution at urban scale. However, state-of-the-art UBEMs use identical building envelope thermal transmittance according to design specifications in model characterization, which neglects the uncertainty in U-values of the bu...

Machine learning is considered a promising method for developing building energy-benchmarking models. However, the high dimensionality of building energy datasets can reduce model accuracy and generalization but increase the computational cost. Meanwhile, the poor interpretability of machine learning models limits the understanding of insights and,...

This paper introduces a database of 34 field-measured building occupant behavior datasets collected from 15 countries and 39 institutions across 10 climatic zones covering various building types in both commercial and residential sectors. This is a comprehensive global database about building occupant behavior. The database includes occupancy patte...

The building sector is one of the largest energy user and carbon emitter globally. To achieve China’s national carbon target, the building sector in China needs to achieve carbon peaking and neutrality targets by 2030 and 2060, respectively. However, data deficiency on building energy and emissions become barriers for tracking the status of buildin...

Renewable energy is important for achieving carbon neutralization. However, power generation from renewable energy sources can be uncertain and uncontrollable. Therefore, understanding the features of energy demand is pivotal for integrating renewable energy sources and storage systems within the entire energy network. Traditional load profiles are...

Buildings contribute to almost 30% of total energy consumption worldwide. Developing building energy modeling programs is of great significance for lifecycle building performance assessment and optimization. Advances in novel building technologies, the requirements of high-performance computation, and the demands for multi-objective models have bro...

The availability of computational power, and a wealth of data from sensors have boosted the development of model-based predictive control for smart and effective control of advanced buildings in the last decade. More recently occupant-behavior models have been developed for including people in the building control loops. However, while important ob...

Embodied carbon emissions of the building sector constitute the majority of carbon emissions. The selection of a building stock development pathway, construction mode, and synergy between the building construction and industry sectors will greatly influence the future embodied carbon emissions in China's building sector. The main purpose of this st...

Besides highly reflecting solar energy, the spectrum-selective radiative cooling materials (RCMs) dissipate heat to outer space especially through the atmospheric window (e.g., 8–13 μm) and achieve sub-ambient temperature under direct sunlight. Not only potentially contributing to Earth’s heat rebalance, the daytime radiative cooling technology but...

Low-income households face long-standing challenges of energy insecurity and inequality (EII). During extreme events (e.g., disasters and pandemics) these challenges are especially severe for vulnerable populations reliant on energy for health, education, and well-being. However, many EII studies rarely incorporate the micro- and macro-perspectives...

Solar hot water (SHW) systems are widely used to save energy and reduce CO2 emissions. The domestic hot water (DHW) usage behavior of occupants has a significant influence on the energy consumption of SHW systems; the operation of SHW systems also affects the DHW usage of occupants. However, there is a lack of quantitative analysis for coordinating...