Stream water for mini split
EddyJay
| Posted in General Questions on
Hi, I have a small stream next to my house which runs year round. I was thinking I could coil some plastic pipe submerged in the stream, and run it up to a car radiator attached to the backside of my mini split. I would put a circulator pump in-line to transfer the btus from the stream. I know this would work well when I’m a/c mode, but I’m wondering how effective it would be at colder temps.
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Replies
It is not worth the risk.
The danger is in cooling mode the unit will evaporate the water and the minerals in the water will be left behind on the coils and block the heat transfer as they become thicker. Also, over time the water will corrode the metal of the coils and allow the refrigerant to leak out.
When in the heat mode the water will often freeze to the coils and force the unit into a defrost cycle.
Walta
EddyJay,
If I understand, you're suggesting the stream water will only circulate through the car radiator and would temper the air that flows to the heat pump. In summer, you'd cool the air and in winter the stream would be warmer than ambient so you'd be heating the air. What you'd be making is essentially a not-so-efficient geothermal heat pump. I can't see why it wouldn't work, but the efficiency and whether it's worth the trouble will depend on the details - temperature ranges, water temperature, materials costs, how much time you have to mess with it, etc, etc. It's an interesting idea for a DIY project in just the right situation. Along those lines, I wonder if there are situations where it makes sense to put an evaporative cooler upstream of the heat pump in arid locations.
What you're proposing is similar to an open loop water to air heat pump.