Humidity Independent Control Air-conditioning System Research Articles

Adaptability of a temperature and humidity independent control air-conditioning system in green office buildings

In order to reduce the energy consumption and improve the economy of air conditioning system, theoretical analysis and energy consumption simulation are used in this paper to explore the adaptability of temperature and humidity independent control (THIC) air-conditioning system in green office buildings. On the basis of the air moisture content and working hours of staff in green office buildings, China was divided into four humidity-hour zones, and several typical cities were selected in each zone for the same building to carry out the analyses of energy consumption simulation and dynamic recovery period of different THIC air conditioning systems in office buildings. The results indicated that in Urumqi, as the representative city of humidity-hour zone I, green office buildings do not suit THIC system; THIC air conditioning system shows obvious advantages over traditional air conditioning in terms of energy saving and economy, and the energy saving rate of the most suitable THIC air conditioning system in Harbin, Beijing and Haikou, as the representative city of humidity-hour zone Ⅱ, zone Ⅲ and zone Ⅳ, reached 28.04%, 24.64%, and 24.42% respectively. Based on the number of humidity-hour, the most suitable THIC air conditioning systems for typical cities in different zone were raised, and a reference for the use of THIC air conditioning system in green office buildings was provided in this paper.

Performance of a temperature and humidity independent control air-conditioning system based on liquid desiccant for industrial environments

Saving energy consumption of air-conditioning systems is becoming increasingly important in industrial buildings. In this study, measurements were conducted to reveal on-site performance of a full fresh air-conditioning system based on liquid desiccant applied in an industrial factory. Operating the system, temperature and humidity independent control (THIC) can be realized. The results reveal that the THIC system requires higher-temperature chilled water and no reheating process because of the adoption of a liquid desiccant dehumidifier, compared with the conventional vapor compression air-conditioning system. Therefore, a competitive system's coefficient of performance of 3.6 can be realized under the THIC system and an annual electricity-saving ratio of 23.3% can be achieved. In this system, the process air is divided into two parts, and the flow rate ratio of these two parts is discussed to further improve the system's performance. An optimal range of the ratio is determined in this study. When adjusting the ratio from the current 0.72 to 0.5, annual electricity consumption of the THIC system can be further saved by 5.4%. This study would provide valuable experience and reference for energy conservation of industrial air-conditioning systems.

Simulation and Analysis of a Novel Cascade Double Cooling Source Temperature and Humidity Independent Control Air-conditioning System

In view of the climate characteristics of hot summer and cold winter area, a novel cascade double cooling source air-conditioning CDCS system is proposed in this paper. The system can achieve heat-humidity independent control in hot and humid summer and high efficiency heating in cold winter. In this paper, theoretical analysis and Aspen Plus simulations are carried out to study the refrigeration of the system under various operating parameters and climatic conditions, meanwhile the comparison between the proposed system and two conventional systems is performed. Results demonstrate that the refrigerating efficiency of the novel system are 52.7% and 22.7% higher than that of the conventional single-cold air-conditioning and dual-cold air-conditioning, under the optimal design parameters.

The Cognition to the Temperature and Humidity Independent Control Air-conditioning System

This thesis introduced the advantages of temperature and humidity independent control air conditioning system compared with traditional air conditioning system and the realization principle of temperature and humidity independent control air conditioning system. Then the thesis introduced the classification of temperature and humidity independent control system and the advantages and disadvantages of each kind of system, and finally summarized the existing problems of temperature and humidity independent control system.

Heat and humidity features and energy saving potential of temperature and humidity independent control air-conditioning system using refrigerant mixture

Heat and humidity features and energy saving potential of temperature and humidity independent control air-conditioning system using refrigerant mixture

Analysis on the Utilization of Temperature and Humidity Independent Control Air-conditioning System with Different Fresh-air Handling Methods

The presented research illustrates the characteristics of Temperature and Humidity Independent Control (THIC) system with different fresh-air handling methods through engineering case studies. The investigated methods include dehumidification with the application of cooling, liquid desiccant, dual cooling sources dehumidification and dehumidification wheel. By analyzing the dehumidification processes on psychrometric charts, this study summarized main design focus then conducted detailed calculation for equipment sizing. Furthermore, this study compares energy consumptions for the four methods. Results show liquid desiccant and dual cooling sources dehumidification are more suitable for general office buildings in terms of energy conservation. Dehumidification wheel method consumes too much energy therefore not applicable for comfort air conditioning systems.

Performance comparison of temperature and humidity independent control air-conditioning system with conventional system

The energy consumption of centralized air-conditioning systems represents a large percentage of total building energy consumption in commercial buildings. The temperature and humidity independent control system, regulating indoor temperature and humidity separately through different approaches, is a feasible improvement to conventional systems. This paper focuses on the performance discrepancies between the temperature and humidity independent control systems and the conventional systems. A typical office building in Guangzhou is chosen for case study and energy performances of three temperature and humidity independent control systems with different outdoor air handling processes are investigated. Compared to the conventional system, energy efficiency ratio for the entire air-conditioning season of temperature and humidity independent control system I using condensing dehumidification is about 10% higher if the dry fan coil unit is adopted; of temperature and humidity independent control system II with high-temperature chilled water for precooling is about 16% higher, and energy efficiency improvement of temperature and humidity independent control system III with heat pump driven liquid desiccant air handling processor is about 22%. For other three cities in China, the energy saving ratio of temperature and humidity independent control system I is about 10%, about 15%–17% of temperature and humidity independent control system II and 20%–23% of temperature and humidity independent control system III. Practical application: THIC air-conditioning system is supposed to be an effective approach for energy saving in buildings. Chosen a typical office building as an example, this paper gives the energy performance discrepancies between the conventional system and the THIC systems for researchers and designers. Annual energy consumptions for different air-conditioning systems are compared, and the energy saving ratios of THIC systems are obtained. The research will be helpful for designing and constructing an energy efficient central air-conditioning system for buildings. In these typical cities or cities with similar climate, THIC system III with the highest energy efficiency is recommended just from the perspective of energy saving.

The Application of Temperature & Humidity Independent Control Air-Conditioning System Based on the Ground Source Heat Pump

The air-conditioning system is discussed in an office building of Yunlong demonstration area, located in the northwest of Zhuzhou city in Hunan province. The climate of Zhuzhou is subtropical monsoon climate and it is highly humid all the year, hot and humid in the summer. The air-conditioning system used the ground source heat pump is the cold and heat source of temperature and humidity independent control system, which has improved the efficiency of the energy use. And the use of the soil thermal energy has improved the energy efficiency of the system.

The Application Analysis of Temperature and Humidity Independent Control System for an Office Building in Beijing

The temperature and humidity independent control air-conditioning system's basic principle and relative equipments was introduced, and it with high energy efficiency and can be driven by low grade heat source. Selects a typical office building located in Beijing as the analysis object. The building annual hourly cooling and moisture loads were calculated by DeST. This system was compared with traditional condensation dehumidification air conditioning system in the COP and the energy saving.

Research of Temperature and Humidity Independent Control Air-Conditioning System

In this paper, the working principle, relevant equipments and characteristics of temperature and humidity independent control (THIC) air-conditioning system were presented. And authors summarized the application status, design conditions and application conditions of THIC air-conditioning system. Through the research of the system application at home and abroad, authors pointed out the engineering limitations and the way to improve and popularize the technology application.

Application of Temperature and Humidity Independent Control Air-Conditioning System—Using for Winding Workshop of Viscose Filament Production in Coastal Regions

Application of Temperature and Humidity Independent Control Air-Conditioning System—Using for Winding Workshop of Viscose Filament Production in Coastal Regions

Performance of temperature and humidity independent control air-conditioning system in an office building

The temperature and humidity independent control (THIC) system, which controls indoor temperature and moisture separately, may be an attractive alternative to existing conventional HVAC systems for its prominent improvement on the overall system performance and utilization of low grade energy resources. In order to verify the effectiveness of THIC system, a pilot project has been implemented in an office building in Shenzhen, China. In the system, liquid desiccant fresh air handling units driven by heat pumps are utilized to remove the entire latent load of outdoor air supplied for the whole building, and chilled water at the temperature of 17.5°C from chiller is pumped and distributed into dry fan coil units and radiant panels to control indoor temperature. This paper presents the results of field test of the system, which shows that the system can provide a comfortable indoor environment even in very hot and humid weather. The COP of the entire THIC system can reach 4.0. According to the energy usage data recorded from the year 2009, the energy consumption of the THIC system in the tested office building was 32.2kWh/(m2yr), which demonstrates magnificent energy-saving potential compared with the conventional air-conditioning system (around 49kWh/(m2yr)).

Research progress in liquid desiccant air-conditioning devices and systems

The developments on liquid desiccant air-conditioning systems were illustrated and summarized in this paper. In order to obtain a better dehumidification (or humidification) performance, liquid desiccant should be cooled (or heated) rather than air. Two fundamental modules were proposed, including basic spray module with extra heat exchanger and total heat recovery device, which could be combined to set up various kinds of liquid desiccant air processors. The operating principle of heat pump-driven outdoor air processor as well as heat-driven outdoor air processor was analyzed. The COPair of the heat pump (or power)-driven outdoor air processor could be as high as 5.0 both in summer and in winter operating conditions. The COPair of the hot water-driven processor (65°C–80°C) was 1.19 and 0.93, respectively, using evaporative indoor exhaust air or cooling water to cool the dehumidification process. The liquid desiccant air processor-based temperature and humidity-independent control air-conditioning system could save 20%–30% operating energy compared with the conventional air-conditioning system.