Waste heat and renewable energy integration in buildings

Abstract

Buildings consume roughly a quarter of the annual global energy supply. Pinch analysis has been successfully applied to industrial processes, and more recently to locally integrated energy sectors. Pinch analysis minimizes the amount of energy that must be supplied to a process to achieve the desired outcome: products in the case of industries; occupant comfort and domestic hot water use in the case of buildings. For the first time pinch analysis is applied in an all-inclusive way to an individual building, integrating waste heat (e.g. greywater) and renewable energy (e.g. solar). A methodological novelty is added to the pinch analysis method to include both continuous and time dependent thermal sources and sinks. The usual hot stream to cold stream heat transfer is replaced as follows: hot stream reserve; hot stream to cold stream heat transfer; cold stream reserve. For a test building, the pinch temperature changes with time: 27.5 °C from October to May, 47.5 °C from June to September. The pinch temperature and its relationship to solar heating and heat pumping are discussed. Innovative design solutions and economic analyses are presented. Depending on the chosen design solution, primary energy (i.e. electricity) consumption can be reduced by 50%.