Papers by Author: Zhi Gang Zhang

Abstract: Photovoltaic and photo-thermal integration PV/T system can efficiently produce heat using solar energy as well as generate electricity in a large scale. Based on the comparison test of solar efficiency between PV/T system with heat pipe cooling and tube plate PV/T system, whereas get the advantage for different PV/T systems in solar utilization.

Abstract: This paper discusses the suitable working fluid applying in small diameter (millimeter scale) gravity heat pipe theoretically. The working temperature, characteristics of material, heat transfer limit and thermal physical properties of working medium of the heat pipe were studied. It is concluded that each aspect capability of heat transfer of R717 is excellent, but its working pressure is a bit high; the synthesized capability of R134a is relatively ideal and can be chosen as the working medium.

Abstract: We propose a new control scheme based on analyzing the problems existed in the original machine tool. We use single chip Microcomputer as controller, stepper motor to drive machine table, and power monitor for grinding contact detecting. The principle of grinding contact detection was elaborated, the structure of computer hardware and software are presented. The developed control system has been used for machine. The results show that the control system runs properly and achieves the desired effect.

Abstract: This paper proposed an approach for a control, which fuzzy logic method was designed and used in the refrigeration system based on the summary of the common control methods on electronic expansion valve (EEV) and variable speed compressor(VSC). The experiment had been carried out, that showed the fuzzy logic controller achieve more stable superheat and water temperature values against to a disturbance and had good energy saving potential.

Abstract: Building energy saving is one of the most important areas in energy saving and emission reduction, but it needs more funds and technology to achieve the target of building energy saving. Lesson from some abroad experiences on Carbon emission trading, this paper analyzes the limitation of the application of CDM (Clean Development Mechanism) in the field of domestic building energy saving, on which an idea to set up a system of domestic civil building energy efficiency trading is presented. The feasibility on the establishment of the system is discussed detailedly.

Abstract: Based on the test data analysis and processing which are acquired from a solar energy/air source compound heat pump system in the actual building, the seasonal energy efficiency ratio under the two modes and the energy-saving rate are obtained. Through the analysis of the energy-saving rate, the energy-saving characteristics of the solar energy/air source compound heat pump system under heating condition is discussed in detailed.

Abstract: The foundation, principle and prior condition and engineering economic Evaluation Criteria of engineering economic analysis are introduced. The economy for a solar energy/air source heat pump system is analyzed. Through a single air-cooled heat pump system, air conditioning in summer + winter heating systems, solar / air source compound heat pump system model analysis and comparison of three systems, integrated initial investment and running costs of both, come to solar / air source compound heat pump system has certain advantages in economical efficiency.

Abstract: A solar assisted air source heat pump (SAASHP) system is proposed to improve heating performance of air source heat pump (ASHP).The proposed system has been applied in two buildings, a series of experimental investigations were conducted in the both applications, it indicated that the SAASHP system gets better heating performance than ASHP system, the coefficient of performance (COP) gets 10% and 65% increase respectively in two applications. It is also concluded that the ratio of solar collector area to construction area significantly affects the improvement of heating performance in SAASHP system. This work may promote further research and more applications of SAASHP system.