English

The project aimed to conduct research on the reasons for pollution caused by HVAC systems. It was found that the reasons vary widely depending on the type of construction, use and maintenance of the system. Filter and ducts are major sources of pollutants, with humidifiers and rotating heat exchangers coming a close second. Heating and cooling coils are less of a problem, as is the effect of air flow. Puts forward a new maintenance guideline based on the existing VDI 6022.

Air conditioning equipment commissioning adjusts the variables of air diffusion, induction ratio and Coanda effect to optimise comfort. Outlines the author's views on employing suitably qualified persons for commissioning, and in the case of larger projects, a commissioning manager. Recommends the use of a hood factor for air balance and system leakage diagnosis. Lists methods available for balancing water based systems, with index balancing being the most cost effective. Recommends also conducting pre-commissioning checks.

States that the design team must set goals in order to successfully achieve high-performance, low energy buildings. The energy design process can help to achieve the desired effect, beginning in the predesign phase and continuing through to commissioning and occupation. A good understanding of various strategies, the setting of aggressive energy targets and employing computer simulations all contribute to the process. After the building envelope has been optimised, the mechanical/electrical/control systems can be designed.

Describes a project to develop strategies and dissemination material to assist the efficient application of solar and passive ventilation in urban buildings. Describes the website, aimed at the informed architect and engineers specialising in HVAC. Features design solutions in the form of case study buildings and design components. Also presents a review of how current regulations encourage/restrict the application of solar and passive ventilation in urban buildings.

The proceedings of this conference cover the following topics: building design process; commissioning, operation and maintenance; controls and measurement; energy and building; heat pump and panel heating and cooling; HVAC systems and equipment; IAQ and ventilation; indoor air pollution; miscellanea; modelling and simulation; museums and historical buildings; noise control and lighting; passive/evaporative cooling and refrigeration; refrigeration and passive cooling, heat pumps, panel heating and cooling; refrigerant substitution issue; and thermal comfort.

A dynamic computer program was used to analyse the operation and performance of a thermal comfort controller for HVAC systems with forced-air ventilators. The software tool used was GEMS (Generalized Engineering Modeling and Simulation). Simulations indicated that when using a conventional thermostat, any form of mechanical ventilation is likely to increase the moisture content of the air inside a conditioned space in a cooing-dominated hot and humid climate. States that mechanical ventilators in this situation may contribute to indoor air quality problems of high moisture levels.

Describes the features of a prototype home designed for a large builder in Michigan, USA, and the results of a series of DOE-2.1E energy simulations performed to assess the impact of various energy efficient aspects. The new features included: improvements to the thermal envelope and mechanical equipment; use of structurally insulated panels (SIPs) for the envelope; high performance, low-E argon-filled windows; a smaller, more efficient boiler; passive cooling design via a central stairwell with operable skylight; a unique mechanical ventilation system that can be scheduled and zoned.

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.

States that hybrid ventilation systems use the strengths of both mechanical and natural ventilation strategies. In the absence of many studies of the operational experience or performance monitoring of the systems, an school in Sweden was retrofitted with a hybrid ventilation system controlled by a building energy monitoring system. The main ventilation power source for this system was the six metre high solar chimneys, which were equipped with low-energy exhaust fans to supplement stack effect where necessary.

Heat transfer in loose-fill attic insulation was investigated in a large-scale model of a ventilated attic built in a climatic chamber. The particular aspect of this study was heat transfer by convection and its effect on heat losses through the attic floor. It was shown by thermal resistance measurements that the measured and calculated thermal resistance of the attic floor is within the margin of error. Air movements were detected in the insulation, sufficient to cause a decrease in the thermal resistance of the attic floor.