An intensive review indicates that among the existing formulae on the sound attenuation in long enclosures, only the geometrical reflection model seems relatively practical. Computations with this model show the following for rectangular long enclosures: with a larger cross-sectional size the relative attenuation from a given section is less but the absolute attenuation with reference to the source power is greater; the efficiency of absorbers is higher when there is less absorption; and obtain a higher attenuation, the absorbers should be evenly arranged in a section.
HVAC system designs must address both high indoor air quality as well as energy efficiency as the awareness of and demand for proper air quality increases. Economic considerations such as installation and operating costs have impaired many conventional system designs to the point of compromised indoor air quality. This paper discusses many HVAC design parameters that arc critical to achieving adequate indoor air quality.
Active sub-slab depressurization (SSD) systems are an effective means of reducing indoor radon concentrations in residential buildings. However, energy is required to operate the system fan and to heat or cool the resulting increased building ventilation. We present regional and national estimates of the energy requirements, operating expenses and C02 emissions associated with using SSD systems at saturation (i.e. in all US homes with radon concentrations above the EPA remediation guideline and either basement or slab-on-grade construction) .
The sensory pollution load and microbial contamination of glass-fibre filters at high and low relative humidity were investigated in an experimental set-up in the laboratory. Dust and particles from the outdoor air were collected in two EU7 glass-fibre filters for a pre-conditioning period of 16-18 weeks during which there was a constant airflow with a velocity of 1.9 m/s through the filters. One of the filters was exposed to outdoor air of approximately 40% relative humidity and 10°C, the other to outdoor air of approximately 80% relative humidity and S0 C.
The term "buffer room" refers in this context to spaces built between thermally, visually, and acoustically "controlled" indoor rooms and the "no controllable" outdoor environment. Examples of buffer rooms are sunrooms, atria, (enclosed) staircases, and air locks. In a long-term research effort carried out in Austria, buffer rooms were studied with regard to their hygrothermal and acoustical performance within a human-ecological framework.
Optimization of solar energy use for low-energy residential houses in Japan is proposed in order to design rational solar energy systems, it is important to recognize the structure of energy consumption of the residential houses as well as the climatic conditions of the region. Using statistical data obtained from an energy survey of residences in Japan, it has been found that the three major portions of purchased energy are space heating, domestic hot water heating, and household appliances (including lighting and cooking).
Login