Assessment of Air Quality Perception and Its Effects on Users’ Thermal Comfort in Office Buildings

Since people spend most of their time in indoor environments, the objective of this work was to study indoor air quality and its effects on users’ thermal comfort. Based on previous data from a building with a central air-conditioning system and two mixed-mode buildings located in the humid subtropical climate of Florianópolis, southern Brazil, statistical analyses were performed. Each user’s subjective answer obtained through a questionnaire was combined with the corresponding environmental conditions measured by instruments. Results showed that improvement in air quality was associated with the reduction of air temperature and humidity ratio. Also, there was a significant influence of thermal and humidity sensation on air quality satisfaction. Users felt more satisfied or neutral with air quality for being in thermal comfort, and not because of the CO2 concentration—which means that air quality perception is influenced by factors other than CO2. This study recommends implementing an air exchange device in split air-conditioners with air recirculation commonly used in mixed-mode buildings in Brazil. It is important to provide suitable indoor ventilation to reduce pollutant concentration, ensure good air quality and prevent respiratory diseases.

Design of Central Air Conditioning Control Acquisition Device Based on IoT Technology

With the rapid development of Internet and electronic technology, the Internet of things (hereinafter referred to as IOT) has become an important way of many intelligent devices, which can improve people’s application of intelligent devices. Through the IOT, we can carry out the research on the centralized monitoring system of central air conditioning [1]. Through the IOT, we can realize the IOT of indoor and outdoor units of central air conditioning, which can realize the important application of practical engineering projects. Through fuzzy algorithm, this paper can improve the overall improvement of the project. Through the cooperation of MCU and GPRS module, we can complete the wireless transmission of data., This can realize computer terminal monitoring and mobile terminal monitoring. Through engineering application, we can realize the automation and information integration of system monitoring, which will greatly improve the monitoring efficiency. Through the development of acquisition device, we can improve the comfort and security of central air conditioning, which will enhance the communication between the physical equipment of the system and the upper server network. Firstly, this paper analyzes the flow of fuzzy PID algorithm. Then, this paper specifies the system diagram of the central air conditioning control acquisition system [2]. Finally, this paper puts forward the important work of system acquisition.

Development of a laboratory nozzle chamber installation for the humidification of buildings

The nozzle chamber, in which water is sprayed into the air stream using mechanical nozzles, is the main unit for these processes in central air conditioning systems (AHUs). The types of nozzles used do not have a sufficiently high effect of interfacial surface forming due to increased metal usage and the broad total dimensions of certain chambers, i.e., they do not have intensive heat and mass transfer. The authors performed testing of the apparatus in the direct iso-enthalpic air cooling mode to improve the performance of the nozzle chamber. Thus, the experiments conducted confirm the relatively high efficiency of FET operation at small values of irrigation coefficient B ≥ 1.0. The area highlighted is characterised by the unstable operation of other nozzle types. Therefore, FET nozzles can be operated at irrigation factor values B = 0.1…1.0. Experiments have shown that this equation is applicable for practical calculations, with a relative error of ±6.7%. The aerodynamic resistance of the spray chamber nozzle chambers is also according to the data not exceeding 160 Pa.

Operation Strategy of Central Air Conditioning Virtual Power Plant Based on Risk Measurement Method

Virtual power plant is an integrated technology and operation mode to realize air-conditioning load participating in power system operation, further benefitting low carbon renewable energy applications. However, the principle of multi-system coupling in central air-conditioning poses a challenge to normal load regulation. Besides, the uncertainties of demand-side resources bring risks to the operation of virtual power plant. In this paper, the regulation characteristics of central air conditioning are obtained by experiment, while the potential of central air conditioning is quantified by a thermodynamic model, further resulting in the central air conditioning could be transformed into a virtual unit model. Then the dynamic capacity optimization strategy is formulated based on the risk measurement theory, while the generation task decomposition strategy is also formulated based on the equal increase rate criterion, thus forming a two-tier operation strategy of virtual power plant. Finally, illustrative case study is constructed to quantitatively analyze the power generation capacity and effectiveness of the virtual power plant. The effectiveness and practicability of the proposed strategy is also verified to benefit low carbon energy applications.

Centralized on-line monitoring system for pipeline and cable environment and fresh air of air conditioning

Aiming at the problem of on-line centralized monitoring error of pipeline and cable environment and fresh air of air conditioning, a utility model is designed, a centralized monitoring system of pipeline and cable environment and fresh air of air conditioning is disclosed, the system structure configuration is optimized, and the system performance is improved by combining multiple central air conditioning controllers, data processors, acquisition servers and other equipment, combined with LabVIEW technology, the system software function and operation process are improved. Finally, the experiment proves that the centralized online monitoring system for pipeline and cable environment and air conditioning fresh air can better reduce the monitoring error and ensure the real-time monitoring quality of pipeline and cable environment and air conditioning fresh air.

Research on Operation Optimization of Central Air Conditioning Cold Source System Based on PSO-SA Algorithm

This paper takes a data center air-conditioning cold source system as the research object. According to the historical operating data of the cold source system in the transition season, a cold source model is built on the EBSILON platform. The total energy consumption of the cold source system is the research goal. This paper establishes an overall optimization strategy based on PSO-SA. A simulation experiment was conducted on a typical day in the transition season, and the results showed that the optimization strategy can achieve 21.68% energy saving based on the original operation mode when the wet bulb temperature in the transition season is low.