Author
Da Yan
Bio: Da Yan is an academic researcher from Tsinghua University. The author has contributed to research in topics: Air conditioning & Fan coil unit. The author has an hindex of 1, co-authored 1 publications receiving 3 citations.
Topics: Air conditioning, Fan coil unit, Variable air volume
Papers
More filters
TL;DR: In this paper, the authors quantitatively describe the asynchronous load demand feature and reveal its relationship with the loss of pump power and heat transfer ability in a centralized air-conditioning water system.
Abstract: On-site investigations show that an asynchronous load feature would greatly influence the operation of water systems for centralized air conditioning. However, the manner of defining the load feature and relating it to its influence quantitatively is still unclear. This article quantitatively describes the asynchronous load demand feature and reveals its relationship with the loss of pump power and heat transfer ability in a centralized air-conditioning water system. The Lorenz curve and the Gini index are introduced in this study and used as indices to depict load features. For a large-scale use in office buildings, shopping malls, and other buildings, the fan coil unit and the variable air volume systems are investigated in this study. The loss of pump power on valves and heat transfer ability under different load profiles are analyzed. This study develops a new perspective of analyzing load patterns and quantitatively explores reasons for the resulting losses in pump power and heat transfer ability in ...
5 citations
Cited by
More filters
TL;DR: A methodological framework for model evaluation from an application-oriented perspective is proposed, with lighting behavior as a case study, and the metrics for evaluating lighting behavior models are identified according to different application scenarios, while the comparison between the measurement and simulation is done by introducing the statistical hypothesis testing.
19 citations
TL;DR: Wang et al. as discussed by the authors proposed a new approach to identify and evaluate actual demands characteristics, and their distribution in a quantitative and graphical manner, which can be used to effectively quantify the heating demand and evaluate its non-uniform degree.
TL;DR: In this paper , the authors analyzed the changes in wetland distributions at global, continental, typical regional, and national scales and the conversions between wetlands and other land cover types in the last 20 years.
Abstract: Knowing the distributions and changes in global wetlands and their conversion to other land cover types could facilitate our understanding of wetland development, causes of variations, and decision-making for restoration and protection. This study aimed to comprehensively analyze the changes in wetland distributions at global, continental, typical regional, and national scales and the conversions between wetlands and other land cover types in the last 20 years. This study used GlobeLand30 (GL30) data with a 30 m resolution for the years 2000, 2010, and 2020. The main findings of this study are as follows: (1) the area of wetlands continued to increase globally from 2000 to 2020, with a total increase of approximately 4%. Wetland changes from 2010 to 2020 were more significant than those from 2000 to 2010. The regions with significant wetland changes were mainly in the north middle- and high-latitude, and the equatorial middle- and low-latitude, and Oceania and North America were the continents with the highest increase and decrease, respectively; (2) the major conversion of wetlands was mainly natural land cover types, including forest, grassland, water, and tundra, and there were minor conversions due to human activities, including the conversion of wetlands to cropland (~4600 km2) and artificial land (~3400 km2); (3) from 2000 to 2020, the increase in global wetlands was uneven, while the decrease was nearly even at a national scale. Australia had the highest increase due to the conversions from grass, bare land, and water, and Canada had the highest decrease due to the conversion into tundra and forest. The analysis results could more comprehensively characterize the distributions and changes of global wetlands, which may provide basic information and knowledge for related research work and policymaking.