Pingfang Hu

Numerical Simulation of Air Quality for ICUs

Intensive care units (ICUs) adopted contamination control & air-conditioning technology to insure indoor air quality, which could afford upper cleanliness and comfort. Air conditioning and ventilation ways affected greatly micro environment in ICUs. The paper discussed reasonable ventilation projects of contamination control and air conditioning in the ICU using numerical simulation method. The variation rules of air quality parameters in ICUs were analyzed to provide technical director for optimal air conditioning and ventilation designs under different ways of air supplying and returning, different numbers of vents, different types of vents and different numbers of air changes. Conclusions showed that top supply and bottom return systems were better than side supply and bottom return systems from the points of view of comfort and cleanliness. The decontamination capacity of shutter air supplying is better than that of perforated plate air supplying. Higher air changes were greatly propitious to removing pollutants.

Comparative study of intermittent operating conditions for hybrid ground-source heat pump

Given the low thermal diffusivity and heat transfer rate of soil, the continuous operation of ground-source heat pump may result in heat accumulation in the soil. Intermittent operation could help heat recovery of the soil and increase the efficiency of the system. This paper used an office building in Wuhan as the research object to modify the conventional hybrid ground-source heat pump (HGSHP) system by creatively designing an intermittent operating condition for this system. The HGSHP system model was built up on Fluent, and one continuous and two intermittent operation conditions were simulated for three years. To get an intermittent control strategy that not only saves energy but also restores soil temperature, energy consumption between continuous and intermittent operating conditions were compared. The simulation results show that the soil heat accumulation problem can be solved under a reasonably designed intermittent operating method, and for buildings located in Wuhan, intermittent operating condition 2 is better than intermittent operating condition 1, and the payback period of the additional initial cost is six years under intermittent operating condition 2.

The Influencing Factor on Test of Parameter of the Rock-Soil Thermal Properties

In this paper, the principle of a measuring device on thermal response test is introduced and a three-dimensional numerical model is developed. What¡¯s more, the effect of testing time, starting time point, ending time point and volumetric specific heat on the calculation results of the thermal response test by two variable parameter fitting method and three-dimensional numerical model are also discussed. It is validated that the volumetric specific heat is not sensitive to the thermal conductivity of the soil and has a little effect on borehole thermal resistance. The initial soil temperature, the end data point and start data point all affect the thermal conductivity and borehole thermal resistance to some extent. An enough length of testing time should be remained.