Room Air Conditioning Strategies

Baturin. Fundamentals of Industrial Ventilation, 3rd English ed., New York Pergamou Press, 1972. 

Sandberg, and E. Skaret, El, Air Change and Ventilation F ffictency—New Aids for Designers, Swedish Institute for Building Research, 1985. 

ASHRAE, ASHRAE Handbook Fundamentals, Atlanta, GA ASHRAE, 1997. 

German guidelines base the division on the resulting airflow pattern within the room rather than distribution methods. They suggest that airflow patterns be divided into four categories hall-filling mixed flow zonewise mixed flow low-momentum, low-turbulence flow for the air supply in the work region and zonewise displacement ventilation. 

This chapter describes a strategy approach for room air conditioning based on the classification and terminology presented by Hagstrom et al. The basis 

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Zonal models can be applied for each room air conditioning strategy (see Section 8.6), but they are mostly used in stratification and zoning strategies with different air distribution methods (see Section 8.7). 

The clarification of the room air conditioning strategies and their separation frtim the practical methods at present creates space for creativity and new innovations and their evaluation. 

A detailed description of the methods for room air conditioning is presented in Chapter 8. Table 2.1 summarizes the strategies. 

In Chapter 2, Terminology, the terminology of zones, systems, and basic strategies for room air conditioning are explained. 

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. 

A similar temperature and contaminant distribution throughout the room is reached with stratification as with a piston. The driving forces of the two strategies are, however, completely different and the distribution of parameters is in practice different. Typical schemes for the vertical distribution of temperature and contaminants are presented in Fig. 8.11. While in the piston strateg) the uniform flow pattern is created by the supply air, in stratification it is caused only by the density differences inside the room, i.e., the room airflows are controlled by the buoyancy forces. As a result, the contaminant removal and temperature effectiveness are more modest than with the piston air conditioning strategy. 

Srratification is a desirable strategy to provide efficient room air condi-noning with much less effort than using the piston strategy. Its mam application in room air conditioning is the thermal replacement method. However, it can also be applied for contaminants without any thermal buoyancy sources that have different density from the room air. Examples of different air distribution methods to create thetma teplacement are presented in Fig. 8.12. 

The aim of the mixing air conditioning strategy is to provide uniform conditions throughout the air-conditioned room. 

However, the use of other room air distribution methods together with certain exhaust, heating, and cooling methods will also lead (intentionally or unintentionally) to the application of the mixing air conditioning strategy. Some examples are shown in Fig. 8.15. 

A clear classification of the ideal strategies will help the evaluation of the present room air distribution methods in different operating conditions. It also creates a solid base for the development and promotion of new innovations in the field. 

Type of reaction C-N bond formation Reaction conditions Methanol, room temperature Synthetic strategy Chan-Lam coupling forming C-N bond Catalyst Cu(I)Cl/air... 

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