ceiling

Dedicated outdoor air systems (DOAS) integrated with ceiling radiant cooling panels as a parallel sensible cooling system are being considered as an alternative to conventional variable air volume (VAV) systems for commercial buildings because of their energy conservation, first and operating costs, and indoor air quality advantages. A pilot DOAS/radiant panel cooling system is being constructed on a university campus to investigate its advantages over alternative cooling systems in

This paper presents a number of advantages (both practical and thermodynamic) of ceiling heating systems compared to under-floor heating. It is estimated that the heat flux from ceiling heating is approximately the same as under-floor heating: the larger exposed surface of the ceiling, and the lower thermal resistance between the water in the pipes and the ceiling surface, compensate for the lower convective heat flux from the ceiling. Using the same water temperature in the pipes, the total heat flux from ceiling heating will be similar to that of under-floor heating.

In this paper, the authors are proposing a concept of a radiant ceiling panel HVAC system integrated with ice storage system to cope with the following requirements : load leveling, energy saving, cost saving and thermal comfort. Series of measurements were carried out on six model office fixtures displayed in a room equipped with that concept of radiant ceiling panel.That system provided a good thermal environment which tallied with the Ashrae et ISO recommandations.The authors plan to introduce this system into real buildings.

The second part of the paper deals with the measurements of the indoor thermal environment and the ventilation performance of a commercial kitchen.Measurements were made with a tracer gas (SF6) which is non-toxic and odorless.A smoke machine (ROSCO) was placed on the floor of the middle of the kitchen while operating the ventilated ceiling system. Air inlets near the floor or at the lower parts of the walls brought fresh air in the lower part of the kitchen and pushed the smoke upward.The results almost agreed with the results of the previous numerical simulation ( in part 1).

The first part of this paper deals with the performance of a ventilated ceiling system. Field measurements were made in a kitchen of a dietitics school in Kyoto practising mass cooking. The kitchen was half equipped with air canopy hoods to compare with the ventilated ceiling system.
A numerical simulation was conducted with CFD in order to understand the trends of the indoor thermal environment of the kitchen.

This paper demonstrates the importance of the combined use of an energy simulation program and a CFD program for an accurate design of two low energy cooling systems : displacement ventilation and a combined chilled ceiling with displacement ventilation.

This paper deals with a CFD simulation of a chilled ceiling in a test chamber. The results demonstrate that a slight non-uniformity in cooling power of the ceiling panels produces a great asymmetry in predicted room airflows.

Thermal comfort obtained with a ceiling cooling system was investigated through experiments with human subjects. Results give their perception of thermal comfort and its relationships with skin temperatures measured at several parts of the body.

This paper analyses through CFD simulation results the removal effectiveness in an office cooled by a chilled ceiling combined with either mixing or displacement ventilation. For passive pollutant sources, both systems provide similar air quality. For active pollutants and when a large volume of all fresh air is supplied, displacement ventilation has better performance.

A building energy similation code (ACCURACY) was used to compare indoor humidity in an office room in a hot and humid climate (Hong Kong weather condiitons) equipped either with a conventional constant volume all air system or with a chilled ceiling and a dessicant cooling system. The chilled ceiling and dessicant cooling provide better indoor humidity environment most of the time. The paper gives indications on how to avoid condensation on ceiling panels.