cooling

The subject of this study is the design of cooled ceiling and displacement ventilation systems in buildings. States that good design of CC/DV systems can lead to better indoor air quality and thermal comfort in comparison to widely used VAV mixing systems. A key design parameter is the cooling load removed by the displacement ventilation. Due to a small vertical temperature gradient, a low DV has a positive effect on thermal comfort, but also has a negative effect on indoor air quality because of the increased mixing of room air.

Proposes an HVAC system which combines chilled ceiling with desiccant cooling, to be used in hot and humid climates where air dehumidification is necessary in order to maintain the indoor air humidity within a comfort zone and to lessen the risk of condensation on chilled panels. The system decouples temperature and humidity control by using desiccant wheel for moisture removal and ceiling panels to control the temperature. Another three systems were viewed to evaluate the system performance and energy savings potential.

The National Death Index was used to monitor a cohort of 72,740 persons for whom information on household air conditioning was available, between April 1980 and December 1985. 2275 deaths occurred. The study attempted to establish whether people in households with air conditioning experienced lower death rates during hot weather. Both central and room air conditioning were considered.

States that heat stress decreases the chance of survival for the elderly and sick. Cites examples of an eightfold increase in expected mortality for persons over 85 years and threefold for those 50-54 years old. Suggests that chronic degenerative disease in the elderly, certain therapeutic drugs and lack of acclimatization are additional risk factors.

In order to determine the impact of heat waves on nursing home occupants and the efficacy of air conditioning in reducing them, a study investigated patterns of mortality in eleven air conditioned and nine un-air conditioned nursing homes in New York City. On the basis of the findings, recommends that nursing homes and other institutions for the elderly located in climates like that of New York City be required to provide air conditioning.

An innovative and potentially energy efficient approach to ventilating and cooling buildings is represented by hybrid ventilation. Discusses the application of hybrid ventilation strategies to building design in the USA.

Natural cooling has an important role in decreasing fuel consumption in buildings. The design is mainly directed at reducing heat gains. The following elements are part of the passive precautions taken: window direction, type of fenestration, window surface areas, outside wall construction, inside thermal mass, thermal insulation, shades, and building configuration. The evaluation of these parameters and of natural cooling's feasibility is done by computer simulation. The article describes a computer program devised for this purpose.

The study developed a method to assess the capability of outdoor air utilized for summer cooling in urban apartments in the hot, humid climate of Taiwan (average yearly temperature 23 Deg C, average humidity 85%). The assessment method is approached using three aspects of identifying the maximum comfort room temperature, estimating the cooling capacity of applied outdoor air volume, and calculating the required outdoor air and pre-cooled outdoor air volumes for cooling through cooling load calculations.

States that buildings in Saudi Arabia are often constructed without attention to the occupant discomfort caused by hot summer temperatures. Single-zone thermostats tend to limit comfort to the sun-side of office buildings, and there is also a possibility of asymmetrical radiation. Describes a pilot study conducted in a room in which airflows and temperatures were measured and then simulated using CFD techniques. Several factors were identified which contributed to the problem.

An investigation was carried out in a multi-family building in New Jersey, USA of eight apartments, including resident interviews about air conditioner usage. Energy consumption for cooling varied widely across similar apartments, due to occupants' diverse beliefs about machine operation and economic considerations. 75% of residents did not use the thermostats, preferring to switch the system on and off according to comfort needs. Concludes that the problem is not lack of user education, but rather poor user-friendliness of air conditioner controls.