microprocessor

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 automated 10-point air sampling network which uses an electron capture detector gas chromatograph to continuously measure changes in sulfur hexafluoride tracer concentration in a residential environment will be described. The injection of the tracer is controlled by a microprocessor which decides to inject sulfur hexafluoride tracer to return its concentration to a preprogrammed set point. Infiltration rates from fan induced pressurization will be compared to the infiltration rates as reported from the replacement of sulfur hexafluoride tracer.

A tracer method was developed for the evaluation of workplace ventilation. Nitrous oxide or freon was used as the tracer. The concentration of the tracer gas was measured with an infra-red analyser. The versatility of the tracer technique for industrial hygiene applications was improved by the use of a microcomputer for data calculation, display and storage. Three applications are presented: 1. determination of the capture efficiency of a local exhaust hood, 2. the evaluation of the air leakage of a room, and 3. measurement of the local ventilation rates in a large industrial plant.

A microprocessor system is being developed for occupancy related ventilation control of mechanical ventilation in Brunel University Library. The objective is to reduce space heating costs by decreasing the input of (cold) fresh air to the building below existing (heating season) levels, when the number of occupants in the building is sufficiently small to allow this. The occupancy levels can be measured in terms of CO2 level in the exhaust duct. The microprocessor control system is operational when linked to a CO2 monitor.

A microprocessor-controlled, five point, all-teflon sequential air sampling system interfaced to a continuous formaldehyde analyser, the CEA model TGM 555 Air Monitor which uses the pararosaniline colorimetric method was used tomeasure the seaso

Describes the methods and considerations employed in the development of a detailed monitoring and evaluation programme for passive solar residences. Data analysis is performed by determining the hourly heat transfer of all critical energy transfer components, using an on-site microprocessor based data acquisition system. Discusses air infiltration as one of the components, and describes measurement methods, including pressurisation and tracer gas techniques.

Describes an energy audit procedure developed for determining economically optimal retrofits for a residential building. This audit is a microprocessor -based, interactive, site and house specific package addressing conservation, solar and wind measures. A dymnamic model of heating and cooling load is used to evaluate fuel savings. Special attention is given to the estimation of monthly average air infiltration rates, using a model correlating pressurization results with air infiltration under natural weather conditions.

A model that relates fan pressurization results to infiltration values during the heating season is the basis for infiltration estimates in several different audit programs. Describes the model and presents validation results. The model is used in three different audit strategies. The first is an energy audit to determine economically optimal retrofits for residential buildings, based on actual on-site measurements of key indices of the house.

Describes an energy audit, developed to determine economically optimal retrofits for residential buildings, based on actual on-site measurements of key indices of the house. Measurements made are; overall energy consumption, furnace efficiency, air leakage measured by pressurization, thermostat settings and window dimensions. The data is fed to a microprocessor and a program suggests retrofits.< Describes the model for estimating heating and cooling loads on the basis of "dynamic degree days", and the algorithm for calculating air infiltration.