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ROOM AIR CONDITIONING Chapter 8

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									ROOM AIR CONDITIONING
      Chapter 8
       PER OLAF TJELFLAAT
           LARS OLANDER
          ESA SANDBERG
          HANNU KOSKELA
           KIM HAGSTRÖM
        ALEXANDER ZHIVOV
         TIMO HAUTALAMPI
          HÅKON SKISTAD
           RALF WIKSTEN
      MAMDOUH EL HAJ ASSAD
    DGB FUNDAMENTALS, Chapter 8
•   INTRODUCTION                             •   Central Recirculation System
•   BASIS FOR AIR CONDITIONING               •   Local Recirculation
    DESIGN                                   •   Conclusion
•   Industrial Process Description           •   TWO-ZONE MODEL DESCRIPTION
                                             •   Zonal Models
•   Requirements for Indoor Environment      •   Two-Zone Model
•   Architectural Design for an Industrial   •   Two-Zone Model Calculation
    Enclosure                                •   References
•   Worker Involvement in the Production     •   EFFECTIVE AND EFFICIENT VENTILATION
    Process                                  •   Ventilation Efficiency Indices
•   Load Calculation                         •   Contaminant Removal Effectiveness
•   Characterization of Room Airflow and     •   Contaminant Removal Efficiency
    Thermal Conditions Based on              •   Air Exchange Efficiency
    Industrial Production Process and        •   Air Distribution Performance Index
    Envelope                                     References
•   Analyses and Actions to Be
    Considered Prior to Performing Room
    Air Conditioning Design
•   AIR RECIRCULATION
•   Introduction
•   Different Recirculation Systems
    DGB FUNDAMENTALS, Chapter 8
•   ROOM AIR CONDITIONING                   •   Zonal Air Distribution
    STRATEGIES                              •   References
•   Introduction                            •   LOCATION OF GENERAL EXHAUST
•   Classification for Room Air             •   Exhausts in Nonstratified Room Air
    Conditioning Strategies                 •   Exhaust of Buoyant Contaminants
•   Piston Strategy                         •   Exhausts in Stratified Room Air
•   Stratification Strategy                 •   Location of General Exhaust to Create
•   Zoning Strategy                             Displacement Flow
•   Mixing Strategy                         •   HEATING OF INDUSTRIAL PREMISES
•   Application of the Strategy in System   •   General
    Selection                               •   The Heating Power Demand
•   Summary                                 •   The Heating Energy Demand
•   References                              •   Radiant Heating
•   AIR DISTRIBUTION METHODS AND            •   Hot Air Blowers
    DIMENSIONING
•   Selection of Air Supply Methods and     •   Air Jets
    Dimensioning                            •   Floor Heating
•   Mixing Air Distribution                 •   References
•   Piston Flow
•   Displacement Flow
         INTRODUCTION
• The scope of this chapter is to show how
  to select a strategy and to make
  calculations to provide efficient room air
  conditioning for an industrial enclosure.
• Design examples for simplified scenarios
  include different ways to condition
  industrial halls.
          BASIS FOR AIR
       CONDITIONING DESIGN
Upon starting design for an industrial enclosure, expected use
   should be described by informing and questioning the
   building owner and future users.
A scenario of the planned industrial enclosure should be
   sketched. The scenario should describe:
   – The different steps of the flow and batch processes of the industrial
     production.
   – Space demands for machinery, tools, working, and stocking areas
     for raw materials and products.
   – Demand for worker involvement in each part of the industrial
     process.
   – Emission of heat and contaminants from each part of the industrial
     process.
   – Environmental requirements for each part of the industrial process.
The factory scenario must be updated with new information as
  the design process evolves.
   Classification for Room Air
    Conditioning Strategies
• The aim of room air conditioning is to
  maintain desired conditions, target levels,
  in the room during different operating
  conditions in the most economical way
  (energy, cost efficiency).
• Depending on the design criteria, the
  designer may choose different strategies
  in order to achieve specified targets.
FIGURE 8.9 The room air conditioning design and evaluation process.
         TABLE 2.1 Ideal room air conditioning strategies

         AIR CONDITIONING                     PISTON               STRATIFICATION                 ZONING                           MIXING
         STRATEGY:
         DESCRIPTION                  To create unidirectio-     To support flow field    To control air conditi-         To provide uniform
                                      nal air flow field over    created by density       ons w ithin the selec-          conditions throughout
                                      the room area by           differences by replacing ted zone in the room            the ventilated space
                                      supply air.                the airflow out from the by the supply air and
                                                                 room area w ith          allow stratification of
                                                                 supply air               heat and contaminants
                                                                                          in the other room areas
         HEAT, HUMIDITY          Room dimension  EX         Room dimension EX             Room dimension   EX             Room dimension      EX
         AND CONTAMINANT
         DISTRIBUTION
         (Pictures)
         X-axis: °C, mg/m3, g/kg
         Y:axis: Room dim.
                (e.g. height)
         SU=supply, EX=exhaust SU                   T, C, x  SU                T, C, x    SU                    T, C, x    SU                    T, C, x

         MAIN                    Room air flow patterns Room air flow patterns            Room air flow patterns          Room air flow patterns
         CHARACTERISTICS:        controlled by low          controlled mainly by          controlled partly by            controlled typically
                                      momentum unidirectional boyancy. Supply air         supply and partly by            by high momentum
                                      supply air flow , strong   distribution w ith low   boyancy.                        supply air flow .
                                      enough to overcome         momentum.
                                      disturbances
         IDEAL
         CONTAMINANT- AND                                                                                                                              1
                                       8




         HEAT REMOVAL
         EFFICIENCY
         TYPICAL APPLICATION
         (An example of a general
         room air distribution
         method )




TABLE 8.8 Ideal Room Air Conditioning Strategies
FIGURE 8.32 The key flow elements in the zoning strategy.
FIGURE 8.33 Two-zone temperature model of the zoning strategy.
FIGURE 8.34 Two-zone concentration model of the zoning strategy.

								
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