The reliability of technological systems with high energy efficiency in residential buildings

•Importance of reliability requirements for the civil systems.•We wanted to extend the reliability parameters to plants of civilian buildings.•We have examined the traditional parameters of reliability.•Allow a precise control from customers and for the product delivered.•Economical savings obtained from high-efficiency plants considering the reliability. The present study wants to highlight the importance of the reliability parameters because of some changes that occurred in modern technology; as for example the necessity of more sophisticated equipments or plants transformed from an auxiliary service to being an actual part of the systems they were originally intended for. Reliability, maintainability and availability are essential features if we want to define the quality that is the ability, of the plant to fulfill a specific requirement. Obviously analyzing the reliability is useful for those plants that must guarantee an uninterrupted service, thus making an estimation of the probability that a malfunctioning, either of component or a security system, can generate an accidental sequence generating a downtime. Even in plants which do not risk the occurrence of a considerable incident, the analysis of reliability can affect positively costs regarding both security and management. The importance of reliability parameters increases when those requirements the system must fulfill change. Anyway these systems have a safe impact on the costs of exertion and management. Such costs will be added to the ones produced by the energy consumption of the plant. By using the word costs we mean: installation and management costs; a high efficient and reliable plant usually has high installation costs and low exertion costs. The opposite situation occurs in highly maintainable plants only under specific circumstances.