Monthly Archives for June 2019

Air-Handling Equipment

Air-handling equipment is available as packaged equipment in many configurations using any desired method of cooling, heating, humidification, filtration, etc. In large systems (over 25 m3/s), airhandling equipment is usually custom-designed and fabricated to suit a particular application. Air handlers … Continue reading

12. June 2019 by Jack
Categories: Air Distribution | Leave a comment

Air Handling Unit

The basic secondary system is an all-air, single-zone, air-conditioning system consisting of an air-handling unit and an air distribution system. The air-handling unit may be designed to supply a constant air volume or a variable air volume for low-, medium-, … Continue reading

12. June 2019 by Jack
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Temperature Versus Air Quantity

Designers have considerable flexibility in selecting the supply air temperature and corresponding air quantity within the limitations of the procedures for determining heating and cooling loads. ASHRAE Standard 55 also addresses the effect of these variables on comfort. In establishing … Continue reading

12. June 2019 by Jack
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Space Heating

Although steam is an acceptable medium for central system preheat or reheat coils, low-temperature hot water provides a simple and more uniform means of perimeter and general space heating. Individual automatic control of each terminal provides the ideal space comfort. … Continue reading

12. June 2019 by Jack
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Zoning – Exterior

Exterior zones are affected by varying weather conditions wind, temperature, and sun and, depending on the geographic area and season, may require both heating and cooling at different times. While the engineer has many options in choosing a system, the … Continue reading

12. June 2019 by Jack
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All-Air System

An ALL-AIR SYSTEM provides complete sensible and latent cooling, preheating, and humidification capacity in the air supplied by the system. No additional cooling or humidification is required at the zone, except in the case of certain industrial systems. Heating may … Continue reading

12. June 2019 by Jack
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AIRFLOW MEASUREMENT IN A FAN COIL WITH ELECTRIC HEAT

Purpose – This procedure describes how to calculate the quantity of airflow in cubic feet per minute (CFM) being delivered by a fan coil containing electric heating elements. Having the correct quantity of airflow is important in order to maintain … Continue reading

12. June 2019 by Jack
Categories: Service Procedures | Leave a comment

COOLING SYSTEM PROPER AIRFLOW RANGE

Purpose — This procedure describes how to determine if airflow across the evaporator in a cooling system is adequate. For proper operation of a cooling system, the blower should be moving from 400 to 450 CFM of air across the … Continue reading

12. June 2019 by Jack
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TEMPERATURE RISE MEASUREMENT IN A FOSSIL-FUEL FURNACE

Purpose – This procedure describes how to measure the temperature rise in fossil-fuel furnaces. Temperature rise is the difference between the return air temperature entering the furnace, and the supply air temperature leaving the furnace. The amount of temperature rise … Continue reading

11. June 2019 by Jack
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FAULT ISOLATION OF NON-REPAIRABLE ELECTRONIC CONTROLS

10. June 2019 by Jack
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