air conditioning

CSTB has built an experimental house MARIA: Mechanised house for Advanced Research on Indoor Air. The house is dedicated to study pollutants transfers, test ventilation systems, settle field investigation methods, and validate computational models. MARIA will be instrumented and automated according to pre-established scenario of operation reproducing parameters related to human presence and behaviour. The human presence is simulated with heat load and water vapour and pollutants emission. The operation of equipments such as doors and windows, domestic devices, will be automated.

Although most of the apartments adopt state-of-the-art convenience facilities, since they have become the most popular housing type in Korea, they depend on natural ventilation for HVAC systems, as traditional floor heating systems (Ondol) are used. On the other hand, the indoor environments of the apartments have become more important, because people stay longer in a room and the room environment is polluted, because of various kinds of interior materials. Accordingly, some apartments apply air conditioning systems using AHU and ventilation systems using heat exchangers.

The study presents a zonal model to evaluate the global comfort of air conditioned buildings. The model calculates various criterions such as Ppo and DR. Sound measure level is estimated with Sabine law. Comparisons with tests are presented.

This study presents a comparison of perceived indoor conditions in both air-conditioned and naturally ventilated buildings.

The demand for duct cleaning has been increasing exponentially over the last few years and to determine objectively if the duct is dirty and has to be cleaned is necessary.All air-handling units from a school district (18 buildings) and representative portions of their associated ductwork were assessed. Results of dirt and contamination are compared to dirt criterias and commented.

CFD simulations and measurements were used in isothermal air-conditioned space of a gymnasium. Different airflow patterns due to different supply air were simulated. Results obtained are correct considering the complexity of boundary conditions.

Thermal mixing of two air streams (outdoor air flow and return air flow) with different temperatures and velocities was studied experimentally in a chamber as it exists inside air handling units, with different adjustments of parallel air dampers. Results show how and where the mixing occurs in the chamber. Indications about the influence of the air dampers adjustment on mixing effectiveness are given.

Describes what could be the requirements of a European standard (not yet numbered) prepared by Technical Committee 156 (Working Group 7) of CEN (European Standardization Committee) about the calculation of energy requirements for buildings with room conditioning systems.

The paper gives an explanation of the phenomenon of attachment of a cold air jet to a ceiling, based on a theoretical analysis. A formula to calculate the distance between the blowing slot and the point where the cold air jet will separate from ceiling is given. The results of calculations using this formula show good agreement with experimental data.

This paper gives formulas for optimal design of all-air systems regarding costs, allowing to calculate the optimum outdoor air rates in office buildings.