Advanced Materials Research Vols. 671-674

Abstract: This project aims to study the optimal control model of the ice-storage system which is theoretically close to the optimal control and also applicable to actual engineering. Using Energy Plus, the energy consumption simulation software, and the simple solution method of optimal control, researchers can analyze and compare the annual operation costs of the ice-storage air-conditioning system of a project in Beijing under different control strategies. Researchers obtained the power rates of the air-conditioning system in the office building under the conditions of chiller-priority and optimal contro1 throughout the cooling season. Through analysis and comparison, they find that after the implementation of optimal control, the annually saved power bills mainly result from non-design conditions, especially in the transitional seasons.

Abstract: Analyses the mechanisms of dynamic heat transfer in the underground works envelope and the simplified calculation method for heat transfer. With the cooperative function of MATLAB, Simulink and COMSOL simulate the dynamic variation of the heat load and validate the simulation results by an experiment.

Abstract: This paper analyzes the significance of air conditioning energy efficient, and analysis from the three aspects of the design, construction, operation and management of the air conditioning system to achieve energy saving measures.

Abstract: The dynamic temperature field of a concrete slab is actively studied in this study with the aiding of the commercial package ANSYS. Fine finite element model of the concrete slab is constructed and different boundary conditions are applied to obtain the temperature distribution within the slab with the aid of the commercial software package ANSYS. The solar radiation model is utilized to estimate the solar radiation received by the slab and the shelter effects are also taken into consideration. The numerical models can successfully predict the structural temperature at different time. The made observations demonstrate that the simulated temperature variation of the concrete slab based on the solar radiation model agrees well with measurement results. It is seen that the numerical models can successfully predict the structural temperature field at different time. The methodology employed in the paper can be applied to other concrete structures as well.

Abstract: To investigate the effect of CaCO₃ concentration and velocity on scaling fouling process on plain and SOFT, experiments have been done at different CaCO₃ concentration and velocity on the two kind tubes. The results are that the homogeneous nucleation rate and the growth rate are both increase when CaCO₃ concentration increases. This make the scaling particle concentration and foulant ions concentration increase, the former gets more scaling on tubes and the later enlarges the heterogeneous nucleation rate and growth rate. Higher velocity decreases the nucleation of scaling, scaling crystal and fouling resistance, but it can prolong the induction period. Higher velocity increases nucleation rate on SOFT first, but the induction period extends and the mass of scaling and fouling resistance decrease. SOFT has a bigger heat transfer coefficient than PT at both clean and fouling conditions and it has smaller fouling resistance even a little more scaling.

Abstract: The time-varying temperature field and stress distribution of a concrete roof slab is actively investigated in this study with the aiding of the commercial package ANSYS. Fine finite element model of the concrete slab is constructed and different boundary conditions are applied to obtain the temperature distribution within the slab. The solar radiation model is utilized to estimate the solar radiation received by the slab and the shelter effects are also taken into consideration. The numerical models can successfully predict the structural temperature gradient and thermal stress distribution at different time. The made observations indicate that the simulated temperature variation of the concrete slab based on the solar radiation model agrees well with measurement results. It is seen that the numerical models can successfully predict the structural time-varying thermal effects.

Abstract: Set up a test-bed, test the pre-cooling section, cooling section, and the units consist of them separately, then analysis the data. Within the experimental range, the best ratio of the secondary air volume and the primary air volume is 1.2 for the pre-cooling section, for the cooling section is 1.69. The outlet air temperature is below its wet bulb temperature for the units, and higher than its dew point temperature.

Abstract: Heat exchange tube with inclined boreholes is a new method that it is efficient and the exploitation and utilization of the underground thermal energy. This method can enhance the buried pipe heat intensity and reduce the area of drilling. This paper set up the model of heat exchange tube with inclined boreholes . Using the FLUENT to simulate the buried pipe mode of the three different direction in ground-source heat pump systems.

Abstract: Based on the introduction characteristics of capillary plane radiation air conditioning systems, we focuse on the analysis phenomenon of radiation asymmetry in the radiant air conditioning systems in the engineering practice , and discuss the condition that produces this phenomenon, and establish mathematical model of radiation asymmetric in the capillary plane air conditioning systems. And we work out the radiation angle coefficient between the human body and the floor, south wall, north wall, east wall , west wall in air conditioning rooms, and expound the radiation asymmetry degree in different parts of air conditioning rooms. The result is of positive significance to research capillary plane radiation air conditioning systems deeply and to improve occupant comfort .

Abstract: The heat-exchange efficiency between buried pipes of the ground coupled heat pump and the surrounding soil is influenced by many factors. To design the Heat Pump better, a three-dimensional FEM method which contains buried pipes and considers changing water temperature along the pipe is applied to simulate the heat exchange progress between buried pipes and the surrounding soil. In this paper, the influence of the inlet water temperature, the flow, operating modes and the distance between branches on the heat-exchange efficiency are analyzed and the reasonable suggestions is proposed to benefit the design and operation of the Ground coupled heat pump.