Chiltrix vs. Multiaqua for hydronic heating and cooling (residential)

[rjk_cmh]

Anyone have experience with either of these systems? I thought about geothermal, but the cost of well drilling is rather high. I'm thinking about hydronic floor heat and hydronic ducted air handlers, with gas boiler(s) for backup heat and DHW. It seems that one of these heat recovery systems could help with efficiency even though they are air-source. The Multiaqua even claims to be able to integrate into a geothermal setup for more efficiency. The Chiltrix has application notes for solar thermal water heat, which is something else I was thinking about - not sure about costs though. Location is central Ohio, new build.

[rjk_cmh]

Also, I like the idea of having all the mechanical components inside the building, and I hate the idea of running glycol/water lines outside in the freezing temperatures. Are there any water-to-water heat pumps that have an option to connect a remote refrigerant condenser?

[TXassaultsun]

I've been contemplating this for a while now as well.
I called Hotspot energy (they own/sell the Chiltrix brand) and got a call back the next day from one of their sales people. We spent over an hour on the phone and they provided a lot of information. A lot of it is on their website as well - test data, design suggestions, price lists, it's all right there, which I think looks really good on them.
MultiAqua has less information on their website. No prices. I called them and the receptionist did transfer me to a sales person - but I got a voice mail. I left a message but have not heard back.

Has anyone here actually installed a Chiltrix CX30 or CX34?

[rjk_cmh]

I haven't gotten any farther with this, and have kind of dropped it for now, but the thing that turned me off of the chilltrix system was the pictures of the insides - it appears to be many cobbled together boards, possibly including a raspberry pi, and not a well-integrated single-manufacturer solution. That gives me pause because of potential future parts availability and risk of failure from all the various moving parts.

[BALloyd]

I am in the middle of connecting 2 multiaqua 5 ton air cooled chillers to some hydronic coils. Cannot tell you much about how they work yet. We did not choose this option. Cleaning up after another contractor got canned. Units are pretty basic. Scroll compressor on 407C. Heat exchanger. Basic controls. Pump in the chiller compartment.

[Juan Madera]

Multi aqua is a good long term player in the residential chiller market. Integrates with hydronic heat and radiant floor applications.

If you build insulated slab on grade with hydronic tubing in the slab, you can integrate some of the cooling load to the floor. Sensible heat removal (and "bank" cooling in the slab at night so you do not need as large a system.) Pair this with a high velocity air handler that has chilled water coil to remove the latent heat and also filter the air and you have a verrrrry cooooool system! Will most definitely require a contractor with some knowledge and experience to make this work according to plan, but my encouragement is extended..

[TXassaultsun]

Definitely keep me posted on your findings.
I said earlier that multi aqua did not return my call - they did actually call back after a few days. Now it's my turn with phone tag.
One of my questions is how their new solar-integrated system works. If it has "solar assist" this may be interesting - you can use solar to offset your heating/cooling costs without the hassle of a grid tied system.

[servicefitter]

Two years ago contacted chiltrex really like their system till i asked about what they had in stock and they only had one 2 ton system and i wanted two. Made the decision not to purchase for possible problems with parts and warrantee. Geo thermo has a 25% tax credit, i went with two 2 ton 3 per wall units mini split heat pumps. Just remember windows, doors and insulation pay for them now or forever. If the house is built right instead of three or four tons maybe get by with a ton less if built righf.

[TXassaultsun]

I was reading about the MHRC-AE where AE stands for Alternative Energy. I decided to call MultiAqua for more information.

The MHRC-AE is basically the same as the MHRC2 , except that it has the Pika Islanding inverter built into it. So it takes 208-240V input, converts it to 380V DC , then inverts it back to 240V for the compressor. The 380VDC rail allows you to connect solar panels and a battery bank. The system will only draw from the grid whatever the solar panels don't produce.

You can buy the Pika system and MHRC2 separately (although it's hard, this is the only place I found that sells them retail https://www.thepowerstore.com/pika-e...-inverter-3748) and build effectively the same setup, so there isn't anything particularly novel about this solution. MultiAqua told me some districts had specific incentives (subsidy/tax credit) for alternative energy air conditioning systems and that was the primary motivation for the integration.

The MHRC2 still seems like a neat system, it's basically a water-to-water chiller with built in cooling tower.

When cooling you can use any amount of the waste heat for DHW, swimming pool or otherwise, and the rest is dissipated through the cooling tower.

When heating it works much the same way but can use its cooling tower to draw heat and work like a heat pump.

MultiAqua doesn't sell to the public directly, so I called a few local distributors to check pricing and availability. There were several local distributors, I called three. One of them had some level of familiarity with the system. One knew the name but knew nothing of the products. One had never even heard of MultiAqua before , even though the sales person was on the list from MultiAqua by name.


The MHRC2 was quoted to me at $22k, the MHRC-AE at $27k. Frankly I suffered a pretty bad case of sticker shock. I had figured maybe $8-10k. I see lots of water-to-water chillers on ebay for less than $10k. So I'm not really sure where the value proposition is in the MultiAqua chiller.

The Chiltrix is a more basic unit (only 2 tons and no heat recovery) but only $2k. The Chiltrix units seem to be interesting in that they are basically a high efficiency mini split system that uses water, so it is much easier to plumb and size than a normal mini split. You can still use these with the Pika inverter all the same.

For me at the moment there does not seem to be an incentive to switch to a hydronic system. A heat pump based water heater would help. Other than that .. perhaps if my wife convinces me to build a swimming pool, then I will have a use for all that heat.

rjk, what did you end up doing?

[rjk_cmh]

rjk, what did you end up doing?

Nothing yet, project still on hold, but as you noted the pricing kind of makes it untenable. I've been reading up on some of John Siegenthaler's books and gaining knowledge of how the systems play together, and I think that their main value proposition is that they have figured out the controls side of things, theoretically.

[TXassaultsun]

It seems that air conditioners can work much more efficiently at part load with variable frequency drive. This is how the mini split systems get the 20+ SEER ratings. Both Chiltrix and MultiAqua are doing this , which is still new in the chiller market. It is also easier on the grid and on the compressor because there isn't the constant cycling action.

I was wondering if you can put a VFD on a commercial grade chiller, I had a thread on it here but didn't get any real answers. Probably "yes but .." there is a lot of R&D involved.

[Juan Madera]

So, build one. Take a basic scroll condensing unit, plum in a coax HX and a circ pump, power with a VFD driven off either the suction pressure or the chilled H2O supply off the Coaxial and have fun! Whole bunches cheaper than a ready roll and a learning experience ta boot.

[TXassaultsun]

So, build one. Take a basic scroll condensing unit, plum in a coax HX and a circ pump, power with a VFD driven off either the suction pressure or the chilled H2O supply off the Coaxial and have fun! Whole bunches cheaper than a ready roll and a learning experience ta boot.

Thinking about it! I'm an electrical engineer so I can certainly do it. I see three phase water-to-water chillers on ebay for $4-8k depending on model and conditions. You can buy 3-phase VFD speed controllers ready made. You'd have to ramp the speed say 40% - 100% based on the water temperature. That's basically what the Chiltrix is doing I think.

Since the VFD's use a DC source voltage you can also tie in the solar system.

On the hot side you can do a similar thing on the cooling tower fan.

When you add it all up you're into the 5 digits cost wise, I'm a little hesitant to spend that much money on an experiment, knowing that it may not work as well as I had hoped.

[TXassaultsun]

I was mistaken on the Chiltrix price, I thought they were $2-3k but they are actually about $4k.
http://www.chiltrix.com/documents/price-list.html

I like it that Chiltrix has the prices right on their website. I spent the better part of the day chasing down MultiAqua pricing.

You can put 2 Chiltrix in parallel to get 4 tons of cooling for $8400 , still much cheaper than the MultiAqua.

When I spoke to them, Chiltrix does have a heat recovery option available if you want it , although I'm not seeing it on their website now. I think it was basically the HotSpot unit. https://www.hotspotenergy.com/reside...water-heaters/ . They said they don't really advertise the option because since the chiller runs at a very low power level for most of the time , the heat level at the output of the compressor is not high enough to make the heat recovery very worthwhile. They said they mainly did it because their competitor (not sure if this is MultiAqua or someone else) offers it so they did not want to lose the business. I personally think it would work well for a pool but probably not for DHW.

At the moment my only waste heat application *is* DHW so my thought is the most bang for the buck is to buy a heat pump type water heater and use this in conjunction with a standard A/C system. The main lure of the hydronic system is the flexibility but not the cost. I like packaged units where the refrigerant is 100% contained with no external lines like with normal split systems.

The only way I see to reduce the operating cost is to add solar panels somehow... or possibly something like an absorbtion cycle chiller if you have a free heat source.

[rnavarro]

Thanks for all the research in this thread!

I too am very interested in the Chiltrix unit, but I haven't pulled the trigger.

I've also seen this unit, which seems similar but a better fit for my use case vs 2 separate chiltrix units:

arcticheatpumps .com/arctic-heat-pump-040a-48-000-btu.html

[servicefitter]

Your forgetting the price of insulated pex, pumps, expansion tank and something for air removal. Can't remember don't the fan coils talk to chiller and don't think there are automatic water shut off valves.If so can you run parallel chillers? Since parts are at a minimum a few days away just might thinking about zoning each system separately.

[Fourthbean]

Your forgetting the price of insulated pex, pumps, expansion tank and something for air removal. Can't remember don't the fan coils talk to chiller and don't think there are automatic water shut off valves.If so can you run parallel chillers? Since parts are at a minimum a few days away just might thinking about zoning each system separately.

I agree, the ancillary costs add up quick. With my system (2900sqft space) it was large enough Chiltrix recommended against an expansion tank but I had to add a second circulation pump. The FCU's don't talk to the chiller, however I'm working on getting mine talking in some way as I have electronic ball valves at each FCU which freaks the chiller out when all of the indoor units turn off (throws a no-flow error code on the CX-34 chiller). I've got some of my experiences documented on YouTube and will be adding more if anyone wants to check it out there. My channel name there is "Beenelife".

[servicefitter]

I'd like to see how your system is piped. Don't know how your getting away without expansion tank and i thought the primary pump was variable speed.

[Spitz]

Had a rash of failed ceiling cassette motors from MultiAqua. They use a low budget motor straight off the boat from China. They last about a year then the bearings fail. We could not find a off the shelve replacement and had to use OEM. We sent a few to our motor supply for repair and analysis. If I remember correctly they were using a high quality bearing but they were overheating. That was over a year ago at a school.

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[Spitz]

Ruamthong was the motor manufacturer.

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