Comparacao entre sistemas de ar condicionado

Design requires the knowledge of what is to be achieved and how is wanted to be achieved. The final definition of a product is usually the result of a cycle of definitions and redefinitions, depending of an interactive and iterative process where many participants take part. Axiomatic Design is one of the latest design theories, which allows a structured decision process. According to Axiomatic Design, two axioms govern good design: the Independence and the Information Axioms.
In the present paper, the Independence Axiom is used to appraise two distinct HVAC design solutions for a high quality office building in Lisbon. High-level functional requirements, as comfort and indoor air quality are considered, and two different kinds of systems where analysed: convective and radiative. In a broad view, both systems can accomplish these requirements, and probably the radiative system can provide a better comfort condition.
However, the radiative system cannot handle all sensible internal loads alone, needing the use of an additional sub-system, fresh air or other, therefore creating an overall coupled system. This violates the Independence Axiom and may increase the information content.
Therefore, care must be taken when using radiative systems in Lisbon-like climates, considering its use only if unchangeable and predictable loads are expected.