Gree "Crown" 18kBTU install

[Xringer]

Last night I decided to set the Sanyo (den) 1 deg higher (20C/68F) than the Gree (main house at 67F).
Net result, the power use by the Gree was low and the Sanyo did 75% of the heating, until early in the AM when it got below about 10F...
At 5AM, the Sanyo was just blowing cold air and using 2.1KW! Turned it off.
Until the temp gets back up over 10F.. (Turned on Den space heaters).

Woke up again at 6:30ish AM:
The Gree was set at 67F, so it's bottom set-point ON level must be 65F..
Because living room was at 65F ! So I moved the setting up to 68F
and it came up blowing warm 108 deg F air.. Main house warmed up to 70F.

It got down to 2.8F at 7:37AM and the Gree was doing fine.
We did have one defrost around 8AM and it worked great. A loud whooshing sound signals when it's over.

Lessons learned.
Set both MS units to the same temperature. (or close den doors).
Set a 10F temperature alarm for shutting down Sanyo.
Set Oil heat back-up 4 degrees lower than Gree (center temp) Setpoint.

[pinballlooking]

Nice. It is good to hear the Gree is heating well at cold temps.
It was 17F here and my bedroom Gree unit was putting out 135 heat.

[Xringer]

I think this 18k BTU unit is a bit undersized for the load when outdoors is really cold.
But, it runs and goes off as expected when the temps are in the normal average range.
And only runs a little longer (and with higher power) when it's really cold..
Right now, it putting out 120F heat and it's 21F outdoors. The power peak passed a while ago.
It seems to run a lot between 1 and 2 KW, not spending a lot of time in the
500 to 800 watt range. But some.
I'm getting used to the way it works and I'm thinking of buying another Gree.

I guess we are going to get back down to 4F again tonight. Colder longer.
The Sanyo will be turned off at midnight and back on abt 10AM Monday.

[WyrTwister]

At this point , do you have a guess as to how a 24,000 BTU Gree would suit your particular application ?

Good to hear the 18,000 BTU model is performing pretty well . :-)

Am I correct in guessing it will perform even better at cooling than it is performing at heating ( when the Autside Air Temperature is low ) ?

God bless
Wyr

[Xringer]

It got down to -0.2°F at 8AM this morning.. The new Gree was using 1.6 to 2kw
when I got up, and putting out 115f air.. The living area was 71F.. (set point 69F).
It's switching on and off just fine..
Used 12.3kwh in 9.5 hours. Averaging 1.3kw, while it was 3 to 4 degrees..

By 8PM last night, it was below 10F, so I was really surprised to see the Sanyo (no defrost cycles)!
still heating the den, using only 480 watts! Until around 5F & 2kw, when I shut it down.
Kept the 'mostly closed off' den at 68F all night using two 900w space heaters.
They hogged 1.8kw, making 6,141 BTUh for much of the night.
Their thermostats were mostly On, until early this AM when I turned one off.

We did use a small amount of heating oil last night. Maybe a gallon. We wanted extra hot water this AM,
because we dishwashed last night + two showers..
(I don't run the hotwater ASHP at night) Clothes wash this morning.
Anyways, we were in Hybrid Heating Mode last night, since the free-flow valve was open,
allowing the baseboards to warm up a little..
In case of grid fail, I don't want the baseboards to freeze up..
Hot water in the burner water jacket (127 gallons) is insurance and provides a little heat to the assist the MS units..

I'm still (slowly) evaluating this setup.. But, I'm starting to think another Gree Crown in the Den, would be a good move.
With that area good to -20f, I wouldn't have to worry about messing with space heaters.
Not sure what BTUs I would put in the den.. But something in the 12kBTU -20F range might allow for skipping the oil free-flow assist..

I hope to be a Grand Dad this week (1st time), so my mind isn't fully on MS stuff..

Edit 10AM:
It just hit 10F and I turned the Sanyo back on.. It's working okay at 670w. Last space heater is off.. Free-flow is off..

[jeff5may]

That sounds about right for the Sanyo unit. It looks to have a more "fuzzy" algorithm to throttle the compressor than the Gree. This was a feature that was campaigned heavily by the marketing guys... less temperature swing, less short cycling, better efficiency, etc. I'm not so super sure about the energy savings in heating mode, though. As your observations show, the unit doesn't just shut down when it can't keep up due to low ambient temperature. Other models can sense this condition and just shut down the outdoor unit automatically.

The Gree unit looks to be living up to its claims during frigid weather. I just wonder if it acts the same as the (Mitsubishi) HHI designs. They tend to favor raw BTU throughput over energy efficiency below freezing. The interstage vapor injection "hyper turbo heat boost" really does seem to keep the unit chugging out heat indoors. How much this affects COP is still unknown in real world conditions. I suppose most users wouldn't care too much as long as the indoor unit kept heating the zone well.

A single 2KW load moving 6KW of heat indoors all night long would lay some serious waste to an electric bill! Obviously the unit is slowing down as the indoor temperature approaches the setpoint, which would save raw power draw at the meter even more. As we know, these heat pumps don't operate like a gas burner, so less instantaneous line power drawn may or may not directly translate to long-term savings. If the unit has better COP in "trickle heat" mode versus "full on turbo" mode, the savings will definitely increase. Regardless of energy savings, perceived comfort will increase over a blast burner, due to the longer temperature decay if the unit falls behind in heating the space during reduce speed operation.

[WyrTwister]

Originally Posted by Xringer

It got down to -0.2°F at 8AM this morning.. The new Gree was using 1.6 to 2kw
when I got up, and putting out 115f air.. The living area was 71F.. (set point 69F).
)

Do you have a formula to compute kw to BTU ? If so , you may be able to compute the cost of using the MS compared to , say a 1500 resistance heater ?

It is my understanding that the higher SEER MS's perform better at low ambient temperatures ?

God bless
Wyr

[creeky]

There was a question about how the Gree manages the defrost cycle.
What are you noticing?
Is there any water turning to ice in the "pan?" Or does the Gree flush the defrost water completely away from the unit?

[Xringer]

A 1500 watt space heater makes 5118.212 BTUh.. (Like my Space heater on full power).

The comparison with an ASHP isn't applicable, because it's BTU output level is not effected by the temperature of the air around it.
If it's input is 1500 watts, it's output is always going to be very close to 5118.212 BTUh.


The Outdoor unit of an ASHP is outdoors where the air temp is always changing.
The colder it gets, the harder it is to pull the heat out of the air..
So, each degree of drop outside, means more watts are needed to put BTU of heat indoors. It's very non-linear..
The sun and the clouds are another big non-linear. When it's sunny,
the power use drops off, because of our southern exposure..
If it gets overcast, power use goes up.. Just like this afternoon..
The relative humidity and blowing snow can increase power use,
because of the snow and frost, reduce full air-flow + defrost cycles etc.

The only thing I can compare, is the LR Gree KWHs with the LR Sanyo KWHs, using past bills..
So far, their power use looks pretty much the same..

[Xringer]

Originally Posted by creeky

There was a question about how the Gree manages the defrost cycle.
What are you noticing?
Is there any water turning to ice in the "pan?" Or does the Gree flush the defrost water completely away from the unit?

I've been watching the slab under the Gree. I see some ice after a night where I've noticed defrost cycles.
But there is no ice visible when looking into the bottom pan..
I did not attach the hose fitting or install the large drain slot plugs.
The bottom pan does have a fat heating wire on the bottom, and it seems to work.

Mostly the cycles run when it's been snowing for a while, but not always.
The power button (logo) LEDs flash while the cycle is running.
Very cold air drifts down from the indoor unit, but no fan action. One reading was 17 deg F..
Then there is a loud gusting sound, followed by normal heating operation..
Looking at the video display, the defrost is almost always 100% effective in removing the blockage..
I can get a similar defrost on a Sanyo, using the dehumidify mode for 15 minutes..