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ECONOMIZER CONTROL SYSTEMS.

Author(s) : DICKSON D. K., TOM S. T.

Type of article: Article

Summary

THE PERFORMANCE OF HIGH LEVEL CUT-OFFS FOR AIR SUPPLY SYSTEMS IS ILLUSTRATED WITH PSYCHROMETRIC CHARTS. ENTHALPY CONTROLS ARE DIFFICULT TO CALIBRATE BECAUSE OF ERRORS IN MEASUREMENT OF RELATIVE HUMIDITY, AND SENSORS REQUIRE FREQUENT RECALIBRATION. A SIMPLER CONTROL SENSES THE OUTDOOR DRY BULB TEMPERATURE AND COMPARES THIS TO AN ADJUSTABLE SET POINT, THE VALUE OF WHICH IS CRITICAL DEPENDING ON THE PREVAILING CLIMATE. THE USE OF COMPUTERISED WEATHER DATA TO PRODUCE AVERAGE WEATHER LINES ON A PSYCHROMETRIC CHART IS DESCRIBED. THIS IN CONJUNCTION WITH THE RETURN AIR ENTHALPY GIVES THE DRY BULB TEMPERATURE FOR THE CUT-OFF. EXAMPLES OF ELECTRONIC AND PNEUMATIC SYSTEMS ARE GIVEN TOGETHER WITH SPECIFIC VOLTAGES AND PRESSURES. G.R.S.

Details

  • Original title: ECONOMIZER CONTROL SYSTEMS.
  • Record ID : 1988-0732
  • Languages: English
  • Source: ASHRAE Journal - vol. 28 - n. 9
  • Publication date: 1986
  • Document available for consultation in the library of the IIR headquarters only.

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