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A novel heat recovery ventilator, the membrane-based energy recovery ventilator (MERV) that uses water-permeable hydrophilic membranes to transmit moisture, is developed to save the energy for conditioning ventilation air. The yearly performance of a MERV in Hong Kong is carried out by hour-by-hour calculations. It is disclosed that in hot and humid regions like Hong Kong, about 58% of the energy required for conditioning fresh air could be saved with a MERV annually, which recovers both latent and sensible energy; while only about 10% of the energy could be saved with a traditional sensible only energy recovery ventilator (SERV). Compared to the annual cooling load, the energy saving for fresh air with a MERV Is 12.1%, about 5–6 times higher than that with a traditional SERV.

Sky garden is regarded as one of the green features in high-rise building design. Located in the mid-level of a high-rise, it serves as recreational garden for communal use. Amplifying the natural wind, and combined with the shading effect, a sky garden has its own thermal and wind environment. In this paper, CFD (computational fl uid dynamics) technique is applied to model the wind and thermal comfort of two possible confi gurations of a sky garden: one with 4 sides open and the other with 2 sides open. The wind data obtained from the Hong Kong Observatory are analysed and divided into three cases: i) summer, ii) winter, and iii) days affected by tropical cyclone (TC). For typical summer and winter wind conditions, thermal comfort is analysed, and for the tropical cyclone wind conditions, the wind comfort is analyzed. It is found that the thermal comfort with four openings is better than that with two openings in summer and vice versa in winter. The results also reveal that higher wind speed provides goo...

Hotels located in hot and humid climate frequently suffer from serious molds growth problems, and therefore substantial financial losses may occur due to vacancies. In this paper, the inherent loose RH cantrol of conventional air-canditioning system design is numerically Investigated using annual energy simulation progroms DOE-2.1E and DesiCalcTM. Two technology design options, which Include wrap-around heat pipes, and desiccant-outdoor air dehumidification, are simulated. Although simple re-heat design is not allowed as it stands in energy conservation codes in many countries, the annual energy consumption of such a system is also simulated for comparison purposes. It becomes apparent that desiccant-enhanced air-conditioning systems can realize a close RH humidity control with additional energy use for regenerating the desiccant unit, while it helps reduce the peak electric demand and annual electricity consumption. If heat required for the reactivation of the desiccant comes from a fuel-fired boiler, th...

A non-traditional HVAC (Heating, Ventilating, and Air-conditioning) system: chilled-ceiling combined with desiccant cooling, is proposed for hot and humid regions like Hong Kang. The performance of the combined system is investigated by a building energy simulation code named accuracy. The energy savings effect of the system in comparison with a conventional ail-air system is Investigated, The indoor humidity variations With the system are predicted by a room moisture balance method, It is found that to address the problem of water condensation an ceiling panels, a one-hour in advance air dehumidification Is required for this novel system.

The objective of this study is to investigate the possible transmission mechanism of inter-flat air cross-contamination under the condition of singlesidednatural ventilation. In high-rise residential building with flush windows on the same side, the air pollutants can diffuse from lower flat to adjacent upper flat in the vertical direction related to the interflat air flow through open windows caused by the temperature difference between the indoor air and the air outside of the windows. Based on the validation of CFD models with experimental data given by Heiselberg, the renormalization group (RNG) based k − ε model, together with Carbon dioxide (CO2) used as a tracer, is chosen to reveal this air crosscontamination. Different effects of contamination spread into upper room were evaluated through kinds of cases performed in various conditions. The numerical results demonstrate this possible transmission path.