In most conditioned spaces, the Mixing Jet Ventilation (MJV) systems are commonly installed. Relying on turbulent mixing, MJV homogeneously controls the room environment. However, Indoor Air Quality (IAQ), draft, and noise can sometimes be drawbacks of MJV systems. In late the 70s, Displacement Ventilation (DV) was first introduced. By supplying low supply velocity air from the floor or lower wall, a stratification zone is formed which forces pollutants to be collected near the ceiling and allows clean air to remain in the breathing zone.
In most conditioned spaces, the Mixing Jet Ventilation (MJV) systems are commonly installed. Relying on turbulent mixing, MJV homogeneously controls the room environment. However, Indoor Air Quality (IAQ), draft, and noise can sometimes be drawbacks of MJV systems. In late the 70s, Displacement Ventilation (DV) was first introduced. By supplying low supply velocity air from the floor or lower wall, a stratification zone is formed which forces pollutants to be collected near the ceiling and allows clean air to remain in the breathing zone.
It is not easy to provide simultaneously thermal comfort, proper air quality, efficient energy consumption to building occupants. In this paper an alternative methodology of real-time determination of optimal indoor air condition for HVAC system to achieve those 3 requirements is presented. A 24 hours operating HVAC system of a single-story building was chosen as a case study.The experiment results obtained with the proposed methodology were better than those from a conventional approach.
For that study, 12 office rooms of a "Solar Optimised Building" in Germany have been monitored. The data have been evaluated by a new method for analysis that deals with short and long term measurements and with building simulation. A comparison between monitored data and simulation of a building with passive cooling by night ventilation is made on a long period.
In a VAV system, it is possible to minimize the energy use with an optimal supply air temperature. The theory for such a device is presented. The analyses show that controlling the supply air temperature in an optimal way results in a decrease of HVAC energy use compared with a constant supply air temperature.
The compatibility of energy conservation and thermal comfort in Japanese house with high air-tightness and insulation equipped with the whole-housing heating, ventilation and air conditioning (H.V.A.C.) system was examined by a numerical analysis. In addition to the present situation, several scenarios for achieving the compatibility were supposed. Thermal environment, thermal comfort and electricity consumption of H.V.A.C. system were analyzed throughout a year for each scenario. A combination of proper scenarios was found to be achieved the compatibility.
This paper discusses the concept and performance of a naturally ventilated building with a double-skin facade in Tokyo. The building incorporates a hybrid ventilation system (natural ventilation integrated with air-conditioning systems) that makes use of buoyancy forces generated in a vertical airshaft in the center of the building. Field measurements were made in order to evaluate the performance of the double-skin facade during the summer and winter and also the performance of the hybrid ventilation system during the spring and autumn.
The traditional ways of maintaining cleanliness, temperature and moisture level in anoperation theatre (OT) usually use larger HVAC system and keep both the heating andcooling functions operating at the same time. The temperature and moisture level are thusunder control at the cost of tremendous amount of wasted energy. Incorporating the HVACsystem with the newly developed secondary return air system, the system capacity can bereduced while the energy efficiency can be increased. In this paper, concepts of the secondaryreturn air system are described.
The Energy Conservation in Building and Community Systems program of the International Energy Agency has set up a research working group (Annex 40) on Commissioning of Building HVAC Systems for Improved Energy Performance. The objective of this new Annex is to develop, validate and document tools for commissioning buildings and building services. The paper describes the annex work which includes 5 tasks: 1) the commissioning process 2) manual commissioning tools 3) building energy management system assisted commissioning tools 4) use of models for ommissioning 5) commissioning projects.
The European Community SAVE Directive 76/93, makes mandatory, among other things, for member states to implement an action called Energy Labelling of buildings. This labelling should consist of a description of the energy characteristics and some information about energy efficiency; and is aimed at reducing CO2 emission by means of a parallel reduction in energy consumption. The European Union allows each country to adopt the most suitable methodology according to weather and building industry characteristics and socio-economic context.