Chilled water cooling question

[Talonewo]

On a chilled water air conditioning system with reverse cycle heat… why would not run the water loop through the a heat exchanger in the hot water heater? You could put valves and an expansion tank to close the loop when you wanted to cool. I could do the math to see how much energy could be added to the system but I’m confident it would not be enough to completely heat the boat but I’m sure it would reduce the load on the compressors. If the boat is moving or the generator is on it would be free heat… what am I missing?

 

[JD]

On a chilled water air conditioning system with reverse cycle heat… why would not run the water loop through the a heat exchanger in the hot water heater? You could put valves and an expansion tank to close the loop when you wanted to cool. I could do the math to see how much energy could be added to the system but I’m confident it would not be enough to completely heat the boat but I’m sure it would reduce the load on the compressors. If the boat is moving or the generator is on it would be free heat… what am I missing?

It may not be able to heat the water enough to make a difference. The flow rate through the water heater would be to great to allow any real heat transfer.

 

[twistedtree]

Are you trying to use the reverse cycle to heat the domestic HW, or are you trying to use the domestic HW to heat the boat?

As for drawing heat off the engine while underway to heat the house, that is commonly done with a heat exchanger tied to the engine. Controls are needed to not over cool the engine, and to prevent the reverse cycle heat from all going out through the engine while at dock or anchor, but it can be done.

 

[Searios]

Webasto is actually doing exactly what you are asking. Check their integrated chilled air conditioners, I think they are called Blue Cool.