Passive houses linked to more efficient heating and cooling technologies have been one of the focus in last years. However, to close the loop of the building sector, there is still one open source: wasted heat from grey water. This paper addresses the potentiality of the wasted heat from grey water as a heat source to produce domestic hot water (DHW) based on a heat pump system (HP). A heat pump optimized for these applications, a heat recovery heat exchanger and two variable volume storage tanks compose the system. The main objective of this work is to determine the potential recovery of the wasted heat in order to minimize the building energy consumption. Design guidelines of the components and the analysis of an optimum operation algorithm of the system have been performed in order to minimize CO2 emissions. In addition, an evaluation of the potential heat recovery of the wasted heat is included. As an example, that methodology has been applied to 20 dwellings. Based on that case, the obtained results demonstrate that by recovering 80% of the available recovery heat, the total demand of DHW is satisfied with high levels of comfort and efficiency.

与更有效的加热和冷却技术相关的被动式房屋已成为近年来的重点之一。但是，要关闭建筑行业的循环，仍然有一个开放源：灰水浪费掉的热量。本文探讨了基于热泵系统（HP）的灰水作为热源所浪费的热量产生家用热水（DHW）的潜力。针对这些应用进行了优化的热泵，热量回收热交换器和两个可变容量储罐组成了系统。这项工作的主要目的是确定废热的潜在回收率，以最大程度地减少建筑能耗。为了使CO2排放量最小化，已经进行了组件的设计指南和系统最佳运行算法的分析。此外，包括对废热的潜在热量回收的评估。例如，该方法已应用于20所住宅。基于这种情况，所获得的结果表明，通过回收80％的可用回收热量，DHW的总需求能够以较高的舒适度和效率得到满足。