Domestic hot water heat recovery: Two systems or one?
We have a large footprint house with multiple bathrooms. The Power-Pipe product seems to be an excellent way of recovering shower waste heat. The question is how to deal with multiple bathrooms that are more than 20 feet apart in a 3 story house. A central drain would be an easy otion and allow the use of one power pipe BUT the hot water woudl need to traverse a great deal of PVC pipe before getting to the power-pipe. It would also be complicated to plu,b to feed from the power pipe to to the mulitple showers drawing from it (in order to plumb the cold side of each). In this configuration a Weissman or BUderus system woudl be used as it could also provide some space heating for the radiators.
Another option would be 2 power-pipes, each feeding a separate how water system. This is a renovation of a large ~6500 sqft home and so the idea of 2 DHW systems is not crazy. That woudl allows the natural gas system to be the main system for the house with (perhaps?) a simple electric tank provisioning 2 bathrooms that are distant from it.
Given the cost of electricity, the likelyhoold that PV may well become power of choice, the low cost of electric tanks but hampered the inefficiency of a plain boiler – what does the math work out to be?
Really struggling with this one….