Cooling the garage?

[Adnillien]

Just a follow-up, we had a guy coming out for the estimate of a hybrid heat pump water heater, who actually recommended a tankless system and a mini-split AC.
A 24,000 BTU Samsung unit (RNS24YBT) would cost $3,800. The unit is 18 SEER.
I'm not sure if 24K BTU is sufficient for a 3-car garage in AZ.

It depends on how cool you want the garage and how well insulated it is. I would think that if your goal is around 85 degrees this would be fine even on the hottest days.

 

[ARamsdale]

The battery care information in the manual says:

CAUTION: Avoid exposing your vehicle
to ambient temperatures above 113°F
(45°C) or below -4°F (-20°C) for more
than 24 hours at a time. Prolonged
exposure can greatly reduce battery
pack life and performance. If it is
necessary to exceed these guidelines,
whenever possible plug the vehicle in
to a charging source to provide reliable
thermal conditioning of the battery
pack.

I think the worry is that battery cooling during charging can take a 105 degree garage will over 113. No problem during charging since the battery is being cooled but once the charging is complete the car will go back to sleep in the hot garage.

Luckily, I doubt it would last beyond 24 hours…

 

[EVCar]

It depends on how cool you want the garage and how well insulated it is. I would think that if your goal is around 85 degrees this would be fine even on the hottest days.

Thanks for the input. Whatever I learned in Physics and Heat Transfer has been long gone
Even today, it's 87 inside the garage so I'll be happy with 85.

 

[Steveinarizona]

Just a follow-up, we had a guy coming out for the estimate of a hybrid heat pump water heater, who actually recommended a tankless system and a mini-split AC.
A 24,000 BTU Samsung unit (RNS24YBT) would cost $3,800. The unit is 18 SEER.
I'm not sure if 24K BTU is sufficient for a 3-car garage in AZ.

I had a heat pump hot water heater installed in my garage about a month ago replacing a traditional electric one. With my kids gone. and efficient water appliances, it has been working fine in heat pump only mode. The noise it makes, for me, is not annoying and when I close the door to the garage it basically disappears.

There are so many variables that I have not been able to make a good judgment on whether it is cooling my garage and, if so, to what degree. I have an insulated garage door (just like the picture posted in this thread) and inside walls on two sides leaving only one somewhat shaded wall to the outside. Before I installed it, my garage was running in the 90s. But changes in outside temperature, time of day, whether I am charging my BMW PHEV and if so, whether its AC is running to cool the battery pack, etc, make it hard for me to determine how much cooler it is getting from the heat pump pulling hot air to make hot water.