Integrating HVAC Equipment with Other Building Subsystems

Data now becoming available from prototype low energy residences confirm that peak heating and cooling loads can be reduced by factors of 3 to 5, using currently available technologies. This paper explores the range of candidate HVAC systems capable of dealing with such fundamentally different load profiles as 8??C balance points, spatially non-uniform loads, and non-negligible thermal capacitance. Results reveal surprisingly small differences in overall efficiency among well-designed centralized (ducted) and decentralized systems providing either mechanical or desiccant dehumidification. Centralized systems offer opportunities for integration of domestic hot water heating, and some types of decentralized systems offer the long-term possibility of being integrated into wall panels or other structural elements. Since efficiencies are comparable, system selection is therefore likely to be driven by such factors as initial costs, complexity and reliability.Air Conditioning and Refrigeration Project 21