The design of mixed-mode ventilation and comfort cooling systems have taken another step forward with the construction of the Centre for Mathematical Sciences in Cambridge - the new home for the mathematical genius Stephen Hawking. But how energy efficient are the buildings likely to be?
ASHRAE Standard 55-1992, Thermal Environmental Conditions for Human Occupancy, is mainly a prescriptive standard intended for occupants with primarily sedentary activity. This article discusses some of the issues being addressed during the proposed revision. The proposed revision will include an analytical method based on the PMVPPD method, where different levels of comfort may be specified. Using the analytical method requires better dialog between the client (builder, owner) and the designer.
The operation and performance of forced-air ventilation systems with the aid of a dynamic modeling and simulation computer program are presented. The functions and features of GEMS (Generalized Engineering Modeling and Simulation), a dynamic modeling and simulation software tool, are briefly described. Using GEMS, the effects of different ventilation airflow rates and sensible and moisture efficiencies on the thermal comfort environment within the conditioned space were analyzed.
Dynamic computer simulations were used to compare residential ventilation methods to identifyan approach that would improve indoor air quality with minimum energy penalty while maintainingcomfort.
This paper presents a part of the findings of ASHRAE research project RP-885, a literature review on the responses of disabled persons to thermal environments. An extensive literature review on the impairment of thermoregulation and thermal sensation has been carried out to collect data on physical, physiological, and psychological responses of persons who suffer from various disabilities, diseases, or genetic disorders, as well as those taking medications, and elderly persons.
Relations between indoor neutral temperatures and outdoor temperatures are currently proposed as an "adaptive standard" to supplement ASHRAE Standard 55-1992. They rest on the 1998 ASHRAE database. Humphreys and Nicol drew attention to the depression of the regression coefficient by measurement and formulaic error in thermal comfort indices. This paper applies their suggested correction, and improves the precision of the relations. Comparison is made with similar relations from earlier data. The relation for unheated, naturally ventilated buildings has remained unchanged.
Passive cooling strategies can offer significant opportunities for improving the occupants' ambient comfort conditions whilst reducing the energy consumption in hot climates. This is particularly applicable for buildings located in hot/arid regions with large cooling toads due to the use of mechanical systems for space climatization. This research examines the potential of passive cooling strategies in a commercial building located in a typical hot/arid climate of Mexico.
Human thermal comfort in warm conditions can often be improved inexpensively by increased air movement. Two automatic ceiling fan systems are described that regulate air speed to maintain comfort in changing conditions. One system is based on the ASHRAE comfort standard and the other uses the PMV comfort model. In comfort tests at 29°C and 50% RH both automatic systems provided the same level of comfort at steady state conditions as manual control. However the automatic systems were faster in bringing the subjects to comfort.
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