ASHRAE 90456

Abstract

THE PURPOSE OF THIS GUIDE The design and operation of any refrigerated facility is a balance of several competing factors, including the following: • Function: Does the facility maintain temperature or provide the required cooling in specified operating conditions? • Safety: Is the facility safe to operate? This includes safety for operators, the host community, and the eventual consumers of products from the facility. • Economic: Can the owner afford to build the facility and to operate it profitably? • Environmental: Is the facility’s impact upon the local, regional, and global environment minimal? • Social: Does the presence of the facility contribute positively or negatively to its host community? This can include factors such as direct employment, increasing opportunities for local producers and contractors, and the aesthetics of the facility. As Chapter 2 demonstrates, all of these factors can contribute to the design and operation of a sustainable refrigerated facility. It is also important to realize that sustainability is not a fixed target that is either met or not. Instead, sustainability is a continuum within which it is possible to evaluate and compare options for design and operations. For each facility, the balance of factors that is appropriate for sustainable design and operation will be different. Even at a very detailed level, the design or operational decisions that lead to the more sustainable option can depend on the specific circumstances. To take one example, the defrost method and defrost management program that is more sustainable depends upon numerous factors including the local utility and environmental costs of water and electricity, the latent heat load on the facility, the design of the evaporator heat transfer surfaces, the extent that there is excess cooling capacity in the facility, and the consequences of air temperature changes to the stored product. Thus, it is impossible for this guide to provide a definitive answer for the most sustainable defrost method and operating strategy. Similar considerations apply to most main design and operational decisions. Therefore, the purpose of this guide is to help the reader evaluate for their own specific circumstances which options are more sustainable. The intent is not to provide a list of sustainable options that can be selected. The purpose of the guide is to introduce methods that readers can use for evaluating sustainability.