scholarly journals Control Algorithms and Control Strategies for Variable Primary Flow Chilled Water Systems

Author(s):  
Jinming Yang ◽  
Yi Lin
2021 ◽  
Vol 343 ◽  
pp. 08009
Author(s):  
Cristina Pană ◽  
Cristian Vladu ◽  
Daniela Pătraşcu-Pană ◽  
Florina Besnea (Petcu) ◽  
Çtefan Cismaru ◽  
...  

This paper presents a new conception and analyzes a hyperredundant continuous robot (continuous style manipulator), drive system, and control strategy. The robot includes ten flexible segments and can be extended to several components as needed. The chosen hyper-redundant robot has a continuous infinite hybrid structure (HHRIC), based on hydraulic control with a rheological element. This system combines the advantage of a joint-level drive with a lightweight construction similar to the base-driven robots. It is suitable for tasks such as wiring in hard-toreach areas (caves, subaccounts, steep areas), transportation of fluids or food to areas affected by natural disasters (people buried under ruins), exploration in difficult areas (speleological research). Generally, the control algorithms for hyper-redundant robots are specific to the robots’ constructive particularities to which they have applied and the environment in which they operate. Experimental results validate the proposal robot design and control strategies in virtual reality. As a result, it is concluded that hyper-redundant robots and immersive technologies should play an essential role soon in automated and teleoperation applications.


2012 ◽  
Vol 268-270 ◽  
pp. 1389-1392 ◽  
Author(s):  
You Jie Ma ◽  
Yi Li ◽  
Xue Song Zhou

This paper reviews the development of static synchronous compensator (STATCOM), and analylizes the structure of its main circuit, its working principles and control strategies. At last, this paper comes to a conclusion of technical characteristics of STATCOM and outlook of its development trends. Fast acting STATCOM, a representative of FACTS family, is a promising technology which is extensively used as state-of-the-art dynamic shunt compensator for reactive power control in transmission and distribution system. STATCOM controller employs various solid-state converter topologies, magnetics configurations, control algorithms, and switching techniques and so on. The development of STATCOM controller has been well reported in literature with its versatile application in power system. Thus deep investigation of STATCOM from the perspective of its intelligent control and the configuration of STATCOM’s main circuit is valuable.


1999 ◽  
Vol 20 (6) ◽  
pp. 412-416 ◽  
Author(s):  
Anthony E. Fiore ◽  
Jay C. Butler ◽  
T. Grace Emori ◽  
Robert P. Gaynes

Objective:To help define the scope of nosocomial legionnaire's disease (LD) and to assess use of recommended diagnostic methods and transmission control practices.Methods:We surveyed 253 hospitals participating in the National Nosocomial Infections Surveillance (NNIS) System. The anonymous survey included questions about episodes of nosocomial LD, environmental sampling practices, maintenance of hospital water systems, and diagnostic techniques.Results:Of 192 hospitals that responded, 29% reported at least one episode of nosocomial ID from 1990 through 1996, and 61% of these reported at least two episodes. Of 79 hospitals with transplant programs, 42% reported nosocomial LD, compared with 20% of hospitals without transplant programs. Environmental sampling had been conducted by 55% of hospitals, including 79% of those reporting nosocomial LD.Legionellawere isolated in 34% that sampled potable water and 19% that sampled cooling system reservoirs. Supplemental potable-water decontamination systems were installed in 20% of hospitals. Only 19% routinely performed testing for legionellosis among patients at high risk for nosocomial LD.Conclusions:Nosocomial LD is relatively common among NNIS hospitals, especially those performing organ transplants. Environmental sampling forLegionellais a common practice among NNIS hospitals, andLegionellaoften are isolated from sampled hospital cooling towers and hospital potable-water systems. Hospitals have responded to suspected nosocomial LD infection with a variety of water sampling and control strategies; some have not attempted to sample or decontaminate water systems despite identified transmission.


2020 ◽  
Vol 31 (1) ◽  
pp. 59-68

Modern households are becoming more and more convenient and intelligent by applying new technology to reduce the time spent on house chores. In this study, the authors proposed the mapping, covering strategies, and control algorithms for vacuum cleaner robot. The robot will automatically implement the cleaning task in a single pass. The sensor system includes infrared sensor, 9 Dof MPU 9250, Delta Lidar 2A, ultrasonic sensor to help robots navigate, build maps and detect obstacles. ROS system (Robot Operating System) is used to control and simulate vacuuming operation in real-world environments. The experiments are conducted in order to illustrate the superiority of the proposed approach.


2019 ◽  
Vol 20 (5) ◽  
pp. 246-249
Author(s):  
Sarah C Blake ◽  
Jonathan N Hawley

Background: Over the past several years, there have been more than 100 confirmed cases in US healthcare facilities of Legionnaires’ disease, a severe and potentially fatal pneumonia caused by the Legionella bacterium found in contaminated water systems. Older people and those with weakened immune systems are particularly vulnerable to Legionella, putting long-term care patients at greater risk of infection. Past efforts to address this growing environmental health crisis have been limited to local surveillance programs for testing water systems in multi-family housing units. In June 2017, the Centers for Medicare and Medicaid Services (CMS) required Medicare-certified healthcare facilities to establish water management programs to reduce the risk of Legionella. Methods: We conducted a mixed methods study (surveys, interviews) to examine the adoption and implementation of these guidelines as well as existing Legionella prevention and control strategies in nursing homes in Florida and Georgia. Results: Findings reveal that most nursing homes in these states do not test their water systems for Legionella because either they have never experienced an outbreak of Legionnaires’ disease or do not have a large water system for testing. Conclusion: Nursing home administrators know of the new CMS Legionella testing requirements and are currently developing water management plans.


2021 ◽  
Vol 2042 (1) ◽  
pp. 012067
Author(s):  
Xiaoye Cai ◽  
Junyi Xue ◽  
Alexander Kümpel ◽  
Dirk Müller

Abstract The increasing use of renewable energy in building energy systems has brought considerable challenges for the traditional planning process to develop appropriate control strategies. In previous work, we have introduced the MODI method to support the structured development of mode-based control algorithms, in which operating modes are core elements. However, modeling of energy systems and control algorithms for control tests is time-consuming and error-prone. Identification of permissible operating modes is also unfeasible. The paper introduces a methodology to identify permissible operating modes and model energy systems with mode-based control algorithms in the modeling language Modelica automatically. In the case study, we apply the methodology for an energy supply network and verify the functionality of the methodology. In future work, automated optimization of control algorithms will be integrated into the methodology.


2002 ◽  
Vol 124 (3) ◽  
pp. 300-304 ◽  
Author(s):  
M. Liu

A new variable water (VW) flow system for chilled water system application is presented. Design, operational, and control issues are discussed. Analytical models of pump power and evaporative temperature are developed. The VW systems consume considerably less pump and compressor energy than the primary secondary (PS) systems under partial load conditions for most existing chillers. The VW system consumes less compressor energy since it results in higher refrigerant temperature in the evaporator. The VW systems also have the decoupling capability of the primary and secondary pumping systems.


2011 ◽  
Vol 71-78 ◽  
pp. 1973-1977 ◽  
Author(s):  
Wen Pei Sung ◽  
Tzai Tang Tsai ◽  
Hsien Jung Wang ◽  
Ming Der Chen

The main objective of this on-site study is to use a full-scale HVAC (Heating, Ventilating and Air-Conditioning) system installed in an office building in Taiwan for comparing the power consumption, energy-saving, and CO2reduction by variable primary flow (VPF) chilled water systems for controlling the HVAC. The on-site experimental results indicate that average power consumptions are 44,935 kWh for the constant volume (CV) chilled water systems, and 39,025 kWh for the VPF system. Approximately 19% of the maximum energy-saving rate can be achieved if the HVAC system is operated as a VPF system. Additionally, the reduced quantity of accumulated CO2emission varies from 0 to 44,186 kg with 0.623 kg-CO2kwh-1emission factor during the office hours of 08:00 (a.m.) to 20:00 (p.m.). The results demonstrate that switching the operation of an office building HVAC system from CV to VPF will significantly enhance energy savings and CO2reduction. This study is will offer useful information for evaluating an indoor environmental policy with respect to energy savings and CO2emission reduction for office HVACs used in subtropical regions.


2018 ◽  
Vol 10 (4) ◽  
Author(s):  
Jameson Y. S. Lee ◽  
Kam K. Leang ◽  
Woosoon Yim

This paper addresses the issue of controller complexity for multirotor aerial manipulator (AM) implementation by utilizing a special class of fully actuated hexrotor within the framework of a firmware, which allows standard multirotor actuation modes. Using this platform, manipulator and vehicle dynamics are decoupled, making the airframe inherently more robust than standard multirotor for trajectory tracking in AM applications. Furthermore, its unique design allows for the implementation of modular control strategies. The proposed rotor orientation model makes it possible to decouple the dynamics, allowing full analytical development of the optimal solution. A methodology for analysis, control allocation, and design of this special class of hexrotor is presented, and the implementation of a custom flight stack is demonstrated using a hexrotor prototype in closed-loop flight testing. The flight stack developed is compliant with the open-source ArduPilot Mega (APM) firmware, allowing it to take advantage of all generic multirotor control algorithms. Experimental results are presented to demonstrate feasibility of the system.


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