Heat pumps

[pseudorealityx]

Looks like H2i is the more advanced form of the Flash Injection they had earlier, which is unrelated to friction. The brochure you linked to says:

I see higher compressor speeds mentioned, but nothing about friction.

From how I'm reading it... the bypass circuit that is part of the Flash Injection system allows the compressor to run at higher speeds, which in turn, would put more heat into the refrigerant via compression.

FWIW, the one who mentioned the 'friction' thing was a commercial regional sales manager, who happens to be a PE, so I took what he said mostly at face value. At the time, he wasn't trying to sell me something.

 

[pseudorealityx]

Looks like H2i is the more advanced form of the Flash Injection they had earlier, which is unrelated to friction. The brochure you linked to says:

I see higher compressor speeds mentioned, but nothing about friction.

Just to be clear, I'm not debating the COP/efficiency gains of such technologies, and I understand how the refrigeration cycle can have a COP > 1 since it's just moving heat that's already there. I just don't think a COP => 1 is possible with friction, since friction needs motion and no electric motor producing said motion is 100% efficient.

Agreed... I "think" the key is that it puts "enough" heat into the refrigerant, that it doesn't need to pull heat from the outdoor coil, while still letting it use the cycle to keep the COP high.

This is me thinking out loud, not any official knowledge of their technology.


EDIT: In reality, I think it's just a way to keep getting heat at very low temps, since the last thing they want to do is put aux. heat into their systems, as it would kill one of the big positives their systems have... a much smaller electrical demand because of the inverter start-up capability.

 

[tylernt]

From how I'm reading it... the bypass circuit that is part of the Flash Injection system allows the compressor to run at higher speeds, which in turn, would put more heat into the refrigerant via compression.

Okay, I'm on board with that.

 

[tylernt]

Agreed... I "think" the key is that it puts "enough" heat into the refrigerant, that it doesn't need to pull heat from the outdoor coil, while still letting it use the cycle to keep the COP high.

My understanding is that it's still pulling heat from the outdoor coil, but it's able to do it more efficiently / at lower outside air temperature thanks to the higher compressor RPM. Previously, high compressor RPM would have caused other undesirable side effects, but the H2i stuff lets them bypass the bad stuff.

 

[pseudorealityx]

My understanding is that it's still pulling heat from the outdoor coil, but it's able to do it more efficiently / at lower outside air temperature thanks to the higher compressor RPM. Previously, high compressor RPM would have caused other undesirable side effects, but the H2i stuff lets them bypass the bad stuff.

Agreed... just relies "less" on the outdoor condenser.

So I wonder if they eventually put this technology into their small systems, or if it's just not cost effective on this level. With the introduction of the very inexpensive systems available at the big box stores, I wonder if they'll ever do it.

 

[tylernt]

So I wonder if they eventually put this technology into their small systems, or if it's just not cost effective on this level. With the introduction of the very inexpensive systems available at the big box stores, I wonder if they'll ever do it.

I'm no thermal engineer, but I don't see any major barriers to scaling the technology down. I could see residential applications Canada where they get cold winters and distant rural houses probably aren't piped for nat gas.

 

[pseudorealityx]

There's definately a pool of people who this would be useful for. But by the nature of saying "rural Canada", you're really cutting down the volume you're looking at. Especially since those folks likely don't really have a need for the A/C portion of the heat pump.

 

[fstbusa]

Try mylinkdrive.com for an easier to navigate site for up to date mitsu info.

 

[samoht68]

I live in northeastern PA and have a 40' X 25' frame garage well insulated. I heat it temporarily with an Eden Pure heater that keeps it about 55 F. I was considering one of these, but my problem is I do old car restorations and was told I can't (shouldn't) do any painting or priming in the garage. I have a dust vac for the sanding, so the garage stays relatively clean. Any suggestions???

 

[CampHamp]

I wanted to ensure people are aware that the FE18NA mentioned earlier is a residential Mitsubishi mini-split heat-pump that does use the H2i technology (it sounded like folks posting here thought it was just their commercial systems).

Here is the sales speak on it:

"H2i - The Next Generation in Heat Pump Technology.
The H2i modern outdoor unit gives a new level of performance to Mitsubishi Electric air conditioners, providing the extra heat-generating power it takes to deliver comfort and consistency in extreme climates. H2i units use Mitsubishi Electric's INVERTER-driven scroll compressor technology to achieve the desired room temperature quickly, maintaining it consistently while simultaneously conserving energy. Plus with the integration of Mitsubishi's exclusive H2i flash technology, the MUZ-FE18NA + MSZ-FE18NA Mr. Slim Single Zone Mini Split Hyper Heating Heat Pump System, Wall Mounted, Wireless Remote - 22,500 BTU recovers heat energy that is normally wasted in the flash process at the outdoor coil. This process helps the H2i system overcome issues commonly associated with conventional heat pumps such as decreases in lowside pressure, refrigerant mass flow rate, and operational capacity. As a result the MUZ-FE18NA + MSZ-FE18NA Mr. Slim Single Zone Mini Split Hyper Heating Heat Pump System, Wall Mounted, Wireless Remote - 22,500 BTU delivers 100 percent of rated heating capacity at 5 F and 80 percent at -13 F outdoor ambient temperatures.

H2i heat pumps offer a variety of features designed to take the worry out of temperature control such as automatic restart in the case of power outages and automatic cool/heat changeover. Its long line-length capabilities of up to 245 feet expand application possibilities.

Sometimes cooling spaces such as computer or mechanical rooms and kitchens is necessary even when the temperature is below freezing. Air conditioning down to 0 F outdoor ambient temperature is possible with the addition of a wind baffle. Whether cooling or heating, the H2i gives you the flexibility to temper extreme outdoor temperatures."

There was a good post here earlier to the Service Manual that shows the capacity and efficiency. That is what I read when I decided to buy them for my home and will likely get one for my workshop/barn. Here's my experience....

I purchase two Mitsubishi mini heat-pumps this fall (FE18NA). There are three sizes in this series (9K,12K,18K) and I got two of the 18K size.

I live in Southern NH in an open-plan log cabin. I considered getting a bigger system, but they were not nearly as capable at low temps or as efficient as this line, so I decided to install 2 systems serving the same "open room". An added benefit is that I have redundancy, in case one fails.

Our poorly-insulated cabin is 2800 sqft. These units have kept us at above 70 degrees so far this winter, except once when it was very windy and in the low teens. We're happy to light our wood stove and often do just for the ambiance and "free heat", so we could have had averted other under-capacity days and just not noticed (so do not rely on my case for capacity estimates - have an HVAC pro do the math for you).

Due to their efficiency (heating and cooling), they qualify for the highest NH state rebates and we received $900 x 2 for the installation. Fujitsu has a comparable model but since it is a bit less efficient, our rebate would have been half if we had installed those.