English

Describes the energy efficient retrofit of a residential building following a home performance assessment. Home performance contractors were able to save the owner 40% in annual heating costs with an insulation upgrade, a heating and hot water system replacement and air sealing in the 200 year old house. As part of a promotion exercise for the new Home Performance with Energy Star initiative in New York, the house was the demonstration site for a TV and video production.

Part 1 of this feature discussed the particular moisture and air quality related problems of midrise housing, and took a close look at two cases. This article analyses issues unique to 'Veterans Era Housing' (US housing built for World War II veterans during the 40s and 50s) and presents three cases where moisture problems were successfully addressed.

Presents new empirical formulae for the prediction of the air velocity in front of rectangular (slot) openings. Infers the equations from an experimental study of a common type of local exhaust opening. The formulae describe the three-dimensional velocity field near a rectangular exhaust hood, providing the velocity gradients along suitable directions, parallel to the slot axis. Testing of the formulae showed a good fit to the experimental data.

Two detached houses situated on a hill, a slab-on-grade and a basement building, were used to assess factors that affect the rate of radon entry. For the former, the rate reached its maximum during a particular weather condition when the internal transport of radon was induced by the wind. The latter's rate was highest when the wind blew towards the hill. Changes in barometric pressure did not influence either. Rain affected the rate for the latter house. For the former house the adjusted rate of radon entry showed it to be higher in the morning.

Describes a case of an elementary school which suffers indoor air quality problems as a result of the application of hot coal-tar to the roof, causing major health concerns. Eight roof-mounted air handling units provided heating, ventilation and air conditioning. The space above the ceiling served as the return-air plenum. Four AHUs provided ventilation to most classrooms with variable air volume boxes controlling airflow. Outdoor air intake dampers on each AHU supplied 10% outdoor air to each wing of the school.

Second article in this series. Describes a second type of system that supplies 100% outdoor air, and is projected to save significant energy over standard HVAC. Notes that nearly all schools and large buildings in the US and many other nations operate on the principle that, to control energy costs, building ventilation systems must recycle a majority of indoor air that is already heated or cooled. In the name of energy conservation, many building owners and managers set their ventilation systems to bring in too little outdoor air.

Describes a three-year EU funded research project into the application of passive downdraught evaporative cooling (PDEC) to non-domestic buildings. This paper specifically discusses the use of computational fluid dynamics (CFD) to model PDEC. Using a hypothetical office building in Seville, Spain, it describes modelling techniques used and applications in an investigation of the building's performance.

A performance evaluation of two passive cooling strategies is presented: daytime ventilation and night cooling, for a six storey apartment building in Beijing and Shanghai, China. A coupled, transient simulation approach is used in order to model heat transfer and air flow. CFD is used to simulate wind-driven ventilation, and Fanger's comfort model is used for occupant thermal comfort. States that the results indicate the superiority of night cooling over daytime ventilation, although there is a high condensation risk. For Shanghai neither were found to be suitable.

Makes a comparison between the effects on thermal performance and energy use of a number of pre-cooling and ventilation strategies, suitable for use to reduce peak power demands in office buildings in moderate temperature regions. Describes how simulations were performed for different building envelope parts, and for two levels of internal heat load. Lists the results as significant reductions of required daytime peak power loads which may be obtained by cooling strategies that contribute to lowering the internal mass temperatures.

A study of passive ventilation of a one storey detached building. A hot element of the building, heated by solar energy, induces the air flow. It could be part of a roof or a wall, or a chimney drawing air into the building. No electrical power or mechanical installations are needed, so it is appropriate for use in remote areas and buildings which are not grid-connected. The method can be used to remove toxic gases such as radon. A steady state laboratory model was used for experiments and simulations in steady and transient states.