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2013 | Buch

Temperature and Humidity Independent Control (THIC) of Air-conditioning System

verfasst von: Xiaohua Liu, Yi Jiang, Tao Zhang

Verlag: Springer Berlin Heidelberg

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Temperature and Humidity Independent Control (THIC) of Air-conditioning System focuses on temperature and humidity independent control (THIC) systems, which represents a new concept and new approach for indoor environmental control. This book presents the main components of the THIC systems, including dehumidification devices, high-temperature cooling devices and indoor terminal devices. Other relevant issues, such as operation and control strategy and case studies, are also included.

This book is intended for air-conditioning system designers and engineers as well as researchers working with indoor environments.

Xiaohua Liu is an associate professor at the Building Energy Research Center, Tsinghua University, China. Yi Jiang is a member of the Chinese Academy of Engineering, the director of the Building Energy Research Center, Tsinghua University, China and the director of the China-USA Joint Research Center on Clean Energy. Tao Zhang is a Ph.D. candidate at the Building Energy Research Center, Tsinghua University, China.

Inhaltsverzeichnis

Frontmatter
Chapter 1. Characteristics of Conventional Air-Conditioning Systems
Abstract
Air-conditioning systems play an important role in maintaining the indoor built environment. Coupled heat and mass handling is usually applied for the current state-of-the-art air-conditioning systems. With the advance of society, conventional air-conditioning methods have been challenged by the demand for a more comfortable indoor environment and a higher system energy efficiency. Continuing to improve the energy efficiency and reducing the energy consumption of air-conditioning systems in order to provide a suitable and comfortable environment are foundations to the development of new strategies for the indoor built environment. Taking these requirements into account, the THIC (temperature and humidity independent control) air-conditioning system is generally considered to be a possible and effective solution.
Xiaohua Liu, Yi Jiang, Tao Zhang
Chapter 2. The Basic Idea of the THIC Air-Conditioning System
Abstract
The basic principle of the THIC (temperature and humidity independent control) air-conditioning system is proposed in this chapter. The indoor requirements in terms of heat and moisture extraction together with air quality are investigated first, including the sources and characteristics of the indoor sensible load and latent load. Then the ideal cooling and dehumidifying process as well as the real process of removing heat and moisture are presented. Besides, the main reasons leading to the performance discrepancies between ideal and real processes are discussed. On the basis of these analyses, the THIC air-conditioning system is proposed, and its operating strategy as well as requirements to the components are introduced.
Xiaohua Liu, Yi Jiang, Tao Zhang
Chapter 3. Key Components of the THIC System: Indoor Terminals
Abstract
Terminal devices of the temperature control subsystem consist of a heat exchanger and a heat transfer fluid, which could be a high-temperature chilled water or refrigerant. The heat transfer fluid is circulated inside the heat exchanger, where heat is transferred to the conditioned space through convection or radiation. In the humidity control subsystem, handled outdoor air with a lower humidity ratio is supplied into the conditioned space to remove the indoor moisture load. Terminal devices of the temperature control subsystem and humidity control subsystem complement each other, together achieving the goal to construct the indoor thermal built environment. This chapter introduces different terminal devices for handling the indoor sensible load, including radiant terminal devices and dry FCUs.
Xiaohua Liu, Yi Jiang, Tao Zhang
Chapter 4. Key Components of the THIC System: Outdoor Air Handling Methods
Abstract
In the THIC system, outdoor air is usually handled to a state dry enough to remove indoor moisture for humidity control during cooling season. In this chapter, requirements for outdoor air handling devices within different climate regions are discussed, and the basic air handling devices for heat recovery, dehumidification, and humidification are introduced. Evaporative cooling method, which is feasible for outdoor air handling process in the dry region, the corresponding devices, as well as the analyzing method are introduced. As to the humid region in summer, dehumidification is required to handle the outdoor air to a state dry enough. Condensation dehumidification method and solid desiccant dehumidification method are introduced in this chapter.
Xiaohua Liu, Yi Jiang, Tao Zhang
Chapter 5. Key Components of the THIC System: Outdoor Air Processor Using Liquid Desiccant
Abstract
Outdoor air handling method using liquid desiccant is analyzed in this chapter, which could also be adopted as the humidity control subsystem. Basic properties of liquid desiccant and the design principles for liquid desiccant outdoor air handling processors from the perspective of thermodynamics are presented. Then the performances of liquid desiccant outdoor air handling processors are investigated, including the processors with heat recovery module and with precooling module. At the end of this chapter, a comparison between the liquid desiccant dehumidification method and other dehumidification methods is discussed.
Xiaohua Liu, Yi Jiang, Tao Zhang
Chapter 6. Key Components of the THIC System: High-Temperature Cooling Sources
Abstract
In THIC systems, the required temperature of the high-temperature cooling source during summer is significantly higher than that of conventional systems. As there is no dehumidification requirement, the chilled water temperature could be increased from 5 to 7 °C in conventional systems to 16–18 °C in THIC systems. This offers the opportunity to utilize natural cooling sources, e.g., deep phreatic water, ground-source heat exchangers, and direct or indirect evaporative cooling methods in dry regions.l If no natural cooling sources are available, a vapor compression system can be applied instead. Due to the higher evaporating temperature of the vapor compression cycle, the operating compression ratio of chillers in THIC systems is significantly different from that in conventional systems. Therefore, new requirements are proposed in terms of the chiller design and device development of the vapor compression cycle for THIC systems. In this chapter, typical high-temperature cooling sources are introduced.
Xiaohua Liu, Yi Jiang, Tao Zhang
Chapter 7. Design and Operation of THIC Systems
Abstract
Temperature and humidity independent control (THIC) system adopts the concept of regulating indoor temperature and humidity separately, and, therefore, the system design process including load calculation method, system principle, as well as equipment selection are all based on this concept. There are many types of THIC systems and a variety of system combinations. In this chapter, THIC systems specifically designed for applications in dry area and humid area are introduced. The performance and applicability of such systems used in different areas are compared, and the annual operating strategy and system regulating methodology are discussed.
Xiaohua Liu, Yi Jiang, Tao Zhang
Chapter 8. Application Cases of THIC Systems
Abstract
Recently, THIC system has been paid more attention to and successfully commercialized. Based on the idea of THIC for air-conditioning system, there are various schemes and devices for constructing a THIC system. Application cases with various types of high-temperature cooling sources, outdoor air handling units, and indoor terminals have been discussed in literatures. This chapter focuses on some typical examples of THIC air-conditioning systems applied in commercial buildings with different functions (such as office building, hospital building, large space building, and industrial factory) that are located in different regions and corresponding to different outdoor climates.
Xiaohua Liu, Yi Jiang, Tao Zhang
Chapter 9. Development Tendencies and Perspectives of the THIC Systems
Abstract
As a burgeoning air-conditioning system for commercial buildings, THIC air-conditioning system can better satisfy the regulating requirements of indoor temperature and humidity and embodies a significant potential for energy conservation compared with the conventional system. The design methodology of the THIC system has been incorporated into the national standards and authoritative design handbooks of China. The key devices for the new THIC system have been developed and realized industrialization. Since 2006, there have been more than 20 million m2 commercial buildings that adopted the THIC system in China. Although rapid progresses have been made in developing THIC system, unremitting efforts are still needed for relevant researches and applications in the long term.
Xiaohua Liu, Yi Jiang, Tao Zhang
Backmatter
Metadaten
Titel
Temperature and Humidity Independent Control (THIC) of Air-conditioning System
verfasst von
Xiaohua Liu
Yi Jiang
Tao Zhang
Copyright-Jahr
2013
Verlag
Springer Berlin Heidelberg
Electronic ISBN
978-3-642-42222-5
Print ISBN
978-3-642-42221-8
DOI
https://doi.org/10.1007/978-3-642-42222-5