Introduction

Air cycle technology has arrived. The world's first integrated air cycle system for buildings has been built and tested, and is providing simultaneous heating and cooling. The technology is now ready to move into the commercial sector.

This guide examines the possibilities offered by air cycle technology for building services. The technology can provide simultaneous heating and cooling within buildings, and can be configured to be retrofitted to existing systems or to replace existing systems completely. The guide provides the information to enable the reader to assess the viability of air cycle technology for a particular application. To achieve this it focuses on the practical design, development and testing of a demonstration system in a real building.

It outlines what an air cycle system is and how the basic system works, identifying some practical system configurations. It then investigates the advantages of air cycle systems for buildings, comparing them directly to existing building services. The flexibility of air cycle systems creates many opportunities for replacing current systems, and devising new ones for delivering air conditioning and hot water requirements. The design options for air cycle systems are discussed in relation to the provision of users' needs. These include the options for the individual components within air cycle systems as well as the system configurations themselves.

The design of a demonstration air cycle system that can be readily retrofitted into a building is described. It starts with an outline of the possible configurations to deliver the building's requirements for ventilation, hot water, heating and cooling demands, and their influence on the design of the air cycle system. The equipment used is influenced heavily by the cost, performance, safety and availability of components. The design has been refined using the results of predictive system performance to meet the different load and ambient conditions specified.

The process of the design and integration with building services is discussed in relation to devising a control mechanism to meet the building loads. The development of simple control algorithms and a computer program to automate the control are discussed also.

Finally, the guide provides a detailed description of the installation and use of the demonstration packaged air cycle system. It also shows how the performance characteristics of this system can be used to predict its ability to meet the requirements of specific buildings, and the resulting energy consumption and carbon dioxide (CO₂) emissions.