The first example that I came up with is a circulatory system of our body and a heat exchange system of building. A circulatory system has a function of liberating heat from an inner body. Similarly, a heat exchange system of a building warms the air in the building exchanging heat energy delivered by liquid in pipes.
The second example is a combination of digestive organs in our body and sewage pipes in a building. Each system has the function that discharges waste materials from the body/building.
