Heatpump water heater for multifamily or commerical buildings
Hi,
does anyone know whether heatpump water heaters exist for high usage commercial or multifamily buildings where hot water is produced in a central location ? A rec center where 10 or 20 people may shower at the same time also comes to mind as an application. I imagine that the storage tank would need be at least 500 gallons if not 1000 gallons in such a building. I am asking because I want to see if such buildings can be constructed without fossil fuel usage as part of an environmental advocacy work I am involved in. I appreciate any leads to manufacturer or technologies or even examples of existing buildings of such type that do not run on gas for water heating.
Thanks,
Matthias
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Replies
Also consider an air->water heat pump combined with a separate storage tank.
Sanden systems can be ganged together.
https://foursevenfive.com/sanden-sanco2/
Sanden's residential units are woefully undersized for such an application. There's better stuff out there.
Mitsubishi has some medium to large air-to-water CO2 refrigerant heat pumps designed for serving hot water in hotels, etc. (The size of the buffer tank is usually more important than the max output of the heat pump, the latter of which matters for recovery times.)
https://www.mitsubishi-electric.co.nz/materials/CityMulti/Brochures/2018_QAHV-Heatpump-Brochure.pdf
https://www.ecodan.de/fileadmin/user_upload/downloads/weitere/ME_Heatpump-Brochure_PL_DE_RZ_web72dpi.pdf
In high simultaneous drain + shower flow applications a lot of capacity and efficiency can be gleaned from drainwater heat recovery units (ganged together in parallel to handle peak flows), eg:
http://renewability.com/wp-content/uploads/2017/07/20170913-Power-Pipe-Spec-Sheet.pdf
That would require at least a 4-5' vertical section of drain downstream of the shower, but can return a good third to half (or more, with very tall unis) of the heat going down the drain back into the incoming water stream, lowering the amount of additional heat needed to raise the stored water to an adequate temperature.
Dana, thank you. The link is from the NZ unit of Mitsubishi. Do you know if this is sold in the USA? I could not find it when googling the US product line ... I cannot easily see how much bigger the capacity is relative to a single family residential heater. I guess it has 135K btu power input, which may be as much as 40 times the input of residential single family heatpump water heater? Does that sound about right?
I would check with a local plumber/inspector first to determine the local/ state plumbing code as far as hot water requirements for such a facility.