I've seen geothermal cabinets that do central forced air heating and cooling and also heat hot water with the heat pump or back up electric elements in the water tank. Is there any similar system designed for residential use that combines mini-split heating and cooling with water heating so that there is a single outdoor handler, multiple indoor air handlers, and a hot water tank that is heated either by diverting heat from the indoor handlers, or by heat supplied from the outdoor handler?

A mini split is an air source heat pump that uses refrigerant to accomplish the building space cooling/heating function via the indoor handlers. An air to water heat pump can be used to accomplish building space cooling/heating and domestic hot water heating. An air to water heat pump uses cold/hot water (in lieu of refrigerant) to accomplish the building cooling/heating function via the indoor handlers. There are also systems that can accomplish both the cooling and heating functions at the same time in different zones. However, I am not sure it would be worth the complexity and expense to do this versus a more conventional approach?

It looks like the Daikin Altherma system does what I want, but it seems like the original Altherma is about 10 years old now and perhaps discontinued. The Altherma 3 system seems like it isn't available in the North American market. Any alternatives people have experience with or any ideas if Altherma 3 will eventually make it to North America?

Can you provide links to the specific systems to which you are referring that can can do both the heating and cooling functions, and generate domestic hot water? This is one example of such a system: https://www.daikin.eu/en_us/product-group/air-to-water-heat-pump-low-temperature/daikin_altherma_3.html If you are aware of others I'd love to take a look. Thanks!

Yes, the Daikin Altherma is a popular choice. Some folks have tried the Chiltrix with mixed results:

Chiltrix

Dan, from BlueRidge Company and a contributor to this forum, sells Arctic heat pumps:

Arctic

Thanks! I had not seen these systems before so I'll do my homework on them now and see how others in these forums have found them. Much appreciated.

Mitsubishi has done some recent expermental work with a residential sized 2-zone VRF mini-split compressor and one of their PWFY hydronic VRF modules used in their "Multy-City" commercial air source VRF systems. They're referring to it as the "Mitsubishi Plus H20". I'm not sure if/when it will be released, but there is some details available here:

https://aceee.org/sites/default/files/pdf/conferences/hwf/2015/4D-Doppel.pdf

If your loads are big enough to rationalize commercial VRF system, the Multi-City units start at 6 tons, and can support a large number of zones, including a potable hot water zone.

Yes, speaking of new products, the LG Multi V S family might be an option to consider as well:

LG Multi V S

This is one of the newer systems that can heat and cool at the same time. The performance specs are quite impressive and it was featured on a recent episode of This Old House too.

Posted By sailawayrb on 04 Mar 2019 10:19 PM
Yes, speaking of new products, the LG Multi V S family might be an option to consider as well:

LG Multi V S

This is one of the newer systems that can heat and cool at the same time. The performance specs are quite impressive and it was featured on a recent episode of This Old House too.

But does it heat domestic hot water? There were no hydronic modules (potable or heating-only) indicated in the engineering manual.

The heating capacity tables stop at -4F outdoors, with no indication of pan heater options for extended cold temperature operations, which makes it not well suited for US DOE climate zone 6 or higher locations but would probably be fine for DOE zones 5 & lower.

But the fact that they come as small as 2 tons, and that the 2 tonner can deliver 23,500 BTU/hr @ +5F (a bit more, with oversized cassette capacity) is encouraging, not terrible for a highly flexible VRF system.

Yes, it can service a DHW zone.

And the following is from the spec section of the aforementioned link:

"Industry first single phase, front discharge 6HP VRF system -15.5kW cooling / 18kW heating. With VRF technology, the Multi V S Heat Recovery unit boasts superior energy efficiencies (EER - 3.90 / COP 4.39. Capable of achieving an ESEER value of 8.05 and a heat recovery potential COP of 9.57, in nominal operating conditions) and can provide heating and cooling simultaneously with the option to connect to the LG Hydro kit for the production of domestic hot water. The Multi V S Heat Recovery unit offers a host of unique LG technological developments, including Dual Sensing Control, Smart Load Control and LG’s own 5th generation compressor equipped with High Sided Shell and a new Polyetheretheketone (PEEK) bearing. Designed for small to medium sized spaces Multi V S Heat Recovery is compact and lightweight with considerable installation flexibility."

And it is discussed in this This Old House episode starting at 14:17:

Jamestown Net Zero Remodel

I have used Chiltrix for this exact purpose, and on the next home we are using a SpacePak Solstice Extreme instead. Chiltrix had myriad issues, and poor support.
We are also going to use a HPWH instead of using the SpacePak, due the complexity of the system. K.I.S.S.
You might also look into the Sanden CO2 water heater, and NorAire makes an interesting unit that uses a standard heat pump to heat water, and includes a resistance heat element for backup.
Personally I can't wait for Mitsubishi to roll out their version!

I have used Chiltrix for this exact purpose, and on the next home we are using a SpacePak Solstice Extreme instead. Chiltrix had myriad issues, and poor support.
We are also going to use a HPWH instead of using the SpacePak, due the complexity of the system. K.I.S.S.
You might also look into the Sanden CO2 water heater, and NorAire makes an interesting unit that uses a standard heat pump to heat water, and includes a resistance heat element for backup.
Personally I can't wait for Mitsubishi to roll out their version!

Posted By sailawayrb on 05 Mar 2019 02:55 AM
And it is discussed in this This Old House episode starting at 14:17:

Jamestown Net Zero Remodel

Thanks for that!

Sure thing Dana and thought you would find it interesting! We haven't installed any of these LGs yet and therefore can't provide our personal findings and perspective. However, I expect we will have an opportunity to touch these first-hand before too long.

Posted By sailawayrb on 05 Mar 2019 05:10 PM
Sure thing Dana and thought you would find it interesting! We haven't installed any of these LGs yet and therefore can't provide our personal findings and perspective. However, I expect we will have an opportunity to touch these first-hand before too long.

I look forward to seeing the details on that!

The one in the video in Jamestown RI is a bit more than an hour's drive away from me, but it wouldn't be polite to just knock on their door and give them the third degree on it.

I'd be very curious to see how they break down cost-wise. These systems are definitely NOT your grandma's 2-4 ton multi-split, and would not expect them to come in as cheap, but I'd still expect it to be far cheaper than a ground source heat pump solution.

Dana, I definitely think you should pay them a visit and have a look see... Just tell them who you are and how you advocate green building on GBA and GBT. I am sure they would invite you for a visit. Besides the LG, this was quite an interesting Net Zero remodel in general and if I were that close, I would certainly find a way to see it first-hand...

And there is another new air to water heat pump option coming to market I just received an email about this AM... This one is brought to us from Electro Industries and is called the NorAire Air to Water Heat Pump Boiler. Dennis Schramel, who brought us the innovative Nextgen Boiler several years ago, is also involved with this project too. I don’t know a thing about it, but Dennis did mention to me perhaps a year ago that it was in the works. There will be a webinar about it tomorrow that you can register for here if interested:

NorAire 7 March Webinar Registration

"Greater efficiency is a priority for the homeowner investing in their home's hydronic heating system. Using a high efficiency air source heat pump for hydronic heating is now an option. During this 60-minute webinar we will discuss Electro's NorAire Air Source Heat Pump Boiler. This webinar will cover:
- Concept, how an air source heat pump works and how it can work in a hydronic heat application - Basic sizing & applications
- Piping
- Installation examples"

Yes, there appears to a significant number of next generation air source heat pump systems coming to the market that I expect will be both very impressive and very price competitive.

And you can also view older webinars here:

Older Electro Industries Webinars

Thanks- I just signed up for the 7 March webinar, though I may have to miss the first half... (I suspect it will be available online for later review.)