A new method of test for residential thermal distribution efficiency is currently being developed under the auspices of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). This test method will have three main approaches, or "pathways," designated Design, Diagnostic, and Research. The Design Pathway uses builder's information to predict thermal distribution efficiency in new construction.

The use of computers for simulating building thermal behavior started early at the Royal Institute of Technology in Stockholm, Sweden. The first example of such use dates from a 1957 study of an exterior wall exposed to solar radiation. The simulation program, later named BRIS, has gradually evolved with regard to the users and growing computer capacity. It has been used since the early sixties for research projects, design work and development of new systems, among others the ventilated hollow-core slab (Thermodeck) system.

We present a simple model to calculate the energy loss by free cooling at night. The time dependence of the exhaust air and wall surface temperatures is predicted by a simplified dynamic model that couples air flow, heat transfer, and wall temperature. For given ventilation rate the model predicts that the total heat extracted from the building during the night can be maximized by increasing the heat exchanging surface area and the thermal effusivity, of the wall materials. The influence of ventilation rate on the heat removed by freecooling at night is discussed.

Night cooling is a viable technique in the UK, but there is no suitable commercially available equipment. The BRE has been testing prototype ventilators and concludes that they work although weather, security and acoustics issues need to be addressed.        

As an introductory note, this aims to place the need for cooling for thermal comfort into the context of overall energy efficient building design. Additionally, it stresses the role of ventilation in meeting cooling requirements. Chapters are included on ventilation and cooling requirements; factors affecting cooling load; ventilation and cooling systems; and energy issues in ventilation and cooling, covering space cooling load, plant load and fan energy.

During the cooling season, heat transfer from the attic into the conditioned space of a residence can represent a significant portion of the total envelope heat transfer. Radiant barriers are one method used to reduce this heat transfer. A quasi-steady-state model was developed or predicting attic heat transfer in residences with radiant barrier systems. The model was used to estimate the reduction in cooling load that would occur with a radiant barrier and to identify important construction and environmental parameters that influence this cooling load reduction.

Two residential sized air conditioners were tested in psychrometric rooms at reduced evaporator airflows ranging from 0 to 50% below that recommended by the manufacture of each of the units. Outdoor temperatures ranged from 35 to 49 °C. One of the units used a thermal expansion valve for flow control while the other unit used in short tube orifice. Performance of the units was quantified by the capacity, power, coefficient of performance, and sensible heat ratio.

In this short report we demonstrate the feasibility of using Computational Fluid Dynamics (CFD) for studying the flow in fa.cia.l regions and nasal cavity. A two-dimensional unstructured finite volume flow solver is used. For modelling the turbulence we use a standard k - c: model.