Conventional All-air System Research Articles

Thermal comfort and energy consumption of the radiant ceiling panel system.: Comparison with the conventional all-air system

The purpose of this study is to investigate the various characteristics of a radiant ceiling panel system and their practical application to office buildings. The radiant ceiling panel system and conventional air-conditioning system were compared in terms of thermal comfort, energy consumption, and cost. Thermal environment, along with human response, was tested by using a small meeting room equipped with radiant ceiling panels. The responses were collected by questionnaires given to the male subjects in the room. The experiment for the female subjects was conducted separately. Results show that the radiant ceiling panel system is capable of creating smaller vertical variation of air temperature and a more comfortable environment than conventional systems. When using a cooled ceiling, a small volume of supplied air creates a less draught environment, which reduced the discomfort of feeling cold in the lower part of the body. Numerical simulation of yearly energy consumption and cost estimation were conducted. Typical office rooms located on the 3rd, 4th, and 5th floor of a six-floor building in the Tokyo area were simulated. Since part of the sensible heat load is handled by radiant ceiling panels, the volume of supplied air can be reduced, leading to lower energy consumption for air transport. By using the radiant ceiling panel system in one of the three floors of the simulated building, energy consumption can be reduced by 10%. Estimated pay back time was from 1 to 17 years depending on the market price of the radiant ceiling panel.

96/01941 Comparative assessment of energy requirements for different types of residential buildings in India

Based on hour-by-hour simulation studies, this paper presents the annual energy consumption characteristics of water-panel type cooled-ceiling systems in comparison with conventional all-air systems. In particular, some unique energy saving measures associated with cooled-ceiling systems are numerically studied. The results indicate that a cooled-ceiling system can save much of the fan energy required in all-air systems, and that in the temperate Dutch climate, the system has a compatible energy performance with a VAV (variable air volume) system for office-building cooling purposes. The energy saving possibilities studied include using ceiling water to pre- or re-heat ventilation air and using a cooling tower for free cooling. The paper also demonstrates the possibilities of using a simulation technique to estimate non-conventional energy efficient system designs.

Energy saving possibilities with cooled-ceiling systems

Based on hour-by-hour simulation studies, this paper presents the annual energy consumption characteristics of water-panel type cooled-ceiling systems in comparison with conventional all-air systems. In particular, some unique energy saving measures associated with cooled-ceiling systems are numerically studied. The results indicate that a cooled-ceiling system can save much of the fan energy required in all-air systems, and that in the temperate Dutch climate, the system has a compatible energy performance with a VAV (variable air volume) system for office-building cooling purposes. The energy saving possibilities studied include using ceiling water to pre- or re-heat ventilation air and using a cooling tower for free cooling. The paper also demonstrates the possibilities of using a simulation technique to estimate non-conventional energy efficient system designs.

Hydronic radiant cooling — preliminary assessment

A significant amount of the electrical energy used to cool non-residential buildings equipped with all-air systems is drawn by the fans that transport the cool air through the thermal distribution system. Hydronic systems reduce the amount of air transported through the building by separating the tasks of ventilation and thermal conditioning. Due to the physical properties of water, hydronic systems can transport a given amount of thermal energy and use less than 5% of the otherwise necessary fan energy. This improvement alone significantly reduces the energy consumption and peak-power requirement of the air conditioning system. Radiant cooling has never penetrated the US markets significantly. The scope of this survey is to show the advantages of radiant cooling in combination with hydronic thermal distribution systems, as compared to the commonly-used all-air systems. The report describes the development, thermal comfort issues, and cooling performance of the hydronic systems. The peak-power requirement is also compared for hydronic systems and conventional all-air systems.