automatic equipment

Measurement of air exchange rates, ages of air, and nominal and local ventilation efficiencies in large buildings is often complicated by the building size and compartmentalization, and by the presence of multiple ventilation systems. To allow characterization of the ventilation process in such buildings, a unique experimental system, that employs multiple tracer gases, is being developed at Lawrence Berkeley Laboratory. The tracer gases are sulfur hexafluoride and five halocarbons. The system is designed to be non-obtrusive, highly automated, and relatively easy to ins tall in buildings.

Presents a detailed description of the measurement technique and apparatus used to measure the air change rate in the Spencer St and Linford low-energy houses in Milton Keynes, UK. An automatic air infiltration rig using nitrous oxide tracer gas constant decay was used. Air leakage was also measured by pressurization for the Linford houses and some from the neighbouring Pennyland project.

Describes automatic equipment for measuring thermal comfort based on resultant surface temperature, convective heat flux density, air temperature and relative humidity. Results obtained in an environmental chamber are presented and evaluated.

A new method for measuring interzonal air movement, using up to four different tracer gases simultaneously, has been developed at the Polytechnic of Central London and tested in a solar air-heated experimental house in Peterborough, UK. 

The Aardvark automated system has been developed for continuously measuring the air-exchange rate and 222Rn (radon) concentration in an occupied residence. The air-exchange rate is measured over 90 min intervals by tracer gas decay using sulphur hexafluoride as the tracer gas.

Describes the development of an automated air sampling equipment to measure air infiltration and interzonal air flows. A new matrix analysis method has been developed to calculate single zone infiltration and interzonal air flow rates from measured data. A number of multi-zone experiments have been carried out in the PCL solar heated house at Peterborough, and several single zone infiltration rate measurement experiments have been carried out in a widevariety of buildings. A grab-tube method has been developed for assessing air change rates.

Presents the results to date of the use of the multiple tracer gas technique to determine interzonal airflow and ventilation rates in large, multicelled buildings like offices. This work is part of a wider project designed toextend knowledge of natural ventilation in all types of buildings other than dwellings.

Describes a completely automated constant concentration tracer gas technique for measurement of air infiltration. The equipment consists of five components: 1 a controller, 2 a tracer gas analyzer, 3 an injection and sampling unit, 4 special mixing fans and 5 apparatus for the calibration of the tracer gas flow. The system is controlled by a microcomputer.

An accurate determination of air renewal rate and connective exchanges between units was needed for study of the solar units of the experimental building LESO, in both an occupied and empty state. The CESAR compact equipment for tracer gas (nitrous oxide) measurement was developed. This unit uses a microcomputer to perform a simultaneous and periodical gas analysis in 10 locations. Three tracer gas methods can be used: decay, constant concentration, and continuous flow. The device and regulating program work well with low rates of concentration (100ppm of nitrous oxide).

A discussion of different approaches to indoor air pollutant monitoring is presented. Indoor sampler design criteria are outlined. Grab samplers, personal samplers, passive and single-use devices, and in-situ measurement instruments are compared to novel, syringe/adsorbent tube samplers. These instruments provide automated, sequential, time-averaged collection of avariety of indoor pollutants, including hydrocarbon/halocarbon organic vapours, CO, CO2, HCOH, tobacco smoke, combustion and odorous mixtures, and particulate matter. In addition, the samplers can be used in infiltration studies.