Portable split air to air

QrizB

Would be interesting to see a graph plotting indoor/outdoor temperatures and energy consumption against time.

Sadly I can't easily extract that data from my various ZigBee gizmos. It would need me to take manual readings throughout the day and then plot it by hand, which is more effort than I'm prepared to invest at the moment 😬

The forecast has changed slightly, for both better and worse: the high is lower but it's extending to Friday ...

FreeBear

Sadly I can't easily extract that data from my various ZigBee gizmos. It would need me to take manual readings throughout the day and then plot it by hand, which is more effort than I'm prepared to invest at the moment 😬

May I introduce you to influxdb and grafana - Once set up, instant graphs and you can plot trends over days, weeks, or even years. 😀

QrizB

It almost hit 33C here today, and I'm still running the split with a target temperature of 21C which results in 22-23C in the bedrooms once the fans move the air around. It's also maintaining a similar temperature in the open-plan area downstairs, by virtue of air exchange up and down the stairwell.

I shut the unit down from 1800-1900 to make best use of the Octopus Saving Session.

Energy use for the day so far (1030) is 11.25kWh. I expect we'll nudge over 12kWh by the time midnight comes around, and might've hit 13kWh if I hadn't shut down for an hour.

Tomorrow's forecast has a high of 36C, while Thursday's is 38C. I'll keep reporting how we do.

TroubledTarts

I would say that was a really positive result temp wise and kWh usage wise, especially with the price per kWh you would have paid.

Martyn1981

@QrizB hi mate. You've got me thinking?

Our bedroom is too hot for me to sleep in, but requires no heating through the winter now, probably due to heat rising from downstairs A2A units (one in the room below the bedroom). So no point installing a 'proper' A2A unit.

But upstairs needs a small top up of heat, which I get using oil rads when necessary in the winter. But, no economical win from an A2A upstairs as oil rad top up is very, very small. Also cooling from an extra A2A unit, not installed in our bedroom, would I assume, mostly flow downstairs, and not 'spread' to our bedroom? Though your results appear to prove me wrong(?)

But if I could cool the bedroom when needed, and move the unit elsewhere (upstairs) for heat top in winter, then it might make some sense, two birds one stone. Just a thought / ponder?

I have bottom opening windows, and could easily manufacture some insulation blanks from PIR sheet if necessary. Definitely worth me pondering further I think.

matelodave

I'm guessing that you'd need to fabricate some sort or shelf or hook to suspend the outside unit. Interested to know how QrizB does it.

How heavy is the outside unit assuming that its the bit with the compressor etc and would therefore need some fairly substantial if you need a shelf or hooks to go over the window frame/sill

QrizB

I expect we'll nudge over 12kWh by the time midnight comes around

Yesterday we used 12.13kWh, including the Saving Session shutdown.

So far today we've used 7.4kWh. we're currently drawing 1070 watts with an outdoor shade temperature of 34C. Indoors I'm seeing a range from 22.1C in my north-facing bedroom to 23.7C in the hall downstairs.

All these numbers are from uncalibrated no-brand ZigBee sensors, so handle accordingly.

@Martyn1981 wrote:

Also cooling from an extra A2A unit, not installed in our bedroom, would I assume, mostly flow downstairs, and not 'spread' to our bedroom? Though your results appear to prove me wrong(?)

See temperatures above.

My indoor unit is literally at the top of my stairs. It's blowing cold air across my landing towards one open bedroom door, but on the way a pedestal fan directs some of the air sideways towards the doors to the other two beds. Inside the larger of these a table fan helps with circulation.

It seems to work!

@matelodave wrote:

I'm guessing that you'd need to fabricate some sort or shelf or hook to suspend the outside unit. Interested to know how QrizB does it.

My split was supplied with a window bracket for the outside unit. It wasn't a great match to my casement window: it would have worked better with a sash. I could've Rawlbolted it to the wall just below my window, but decided instead to lash it (the bracket) in place with a pair of luggage straps. It's nigh-on impossible to photograph but I promise you it's relatively neat and tidy!

Edit to add: here's the illustration of the window bracket from the instruction manual.

In my case, the inverted-U channel that's meant to hook over the window frame is instead pulled back snugly against the outside of the frame by the aforementioned straps. The straps pass around the U-bracket and then back to a length of 50x50 timber placed across the window, just above sill height.

Based on a recent YouTube review, it looks like the Midea one comes with a wall bracket that's designed to be bolted in place.

How heavy is the outside unit assuming that its the bit with the compressor etc and would therefore need some fairly substantial if you need a shelf or hooks to go over the window frame/sill

The compressor is inside. Outside is a heat exchanger and a fan, on a box. I'd estimate the weight as around 5-7kg. I'll check the manual and see if it quotes a separate weight for the outside unit.

QrizB

Another day done.

Today outside temperatures peaked just over 34C around 1700 BST. Indoors we mostly stayed below 24C indoors except during the Octopus Saving Session when I switched the aircon off and temperatures in my dining room rose to 25.5C. they fell back below 25 again within an hour of switching the aircon back on.

The highest instantaneous power I saw being pulled by the portable split was almost 1300 watts, and was also at 1700 when the outdoor temperature peaked. As I type this, just after 2200, the outdoor air temperature has finally dropped below 30C and the aircon is taking 630 watts.

Total electricity for the day so far is 14.7kWh, likely to be closed to 16kWh by the time midnight rolls around.

For anyone interested in how my outside unit looks on its bracket, here's a terrible photo.

Hope everyone sleeps well; tomorrow's looking like it might yet be the toughest day of the week.

Martyn1981

Looks great. Certainly making me think.

Just a thought as your window opens outwards, and apologies if this has been mentioned and I've missed it, but could you make a simple PIR sheet blank for the window? Notch for the pipework, and duct tape to allow it to slide tightly into place within the window surround.

It would reflect heat in A/C from solar gain, and probably better insulation than the DG window (closed) in the winter when heating, even with the window ajar.

QrizB

Just a thought as your window opens outwards, and apologies if this has been mentioned and I've missed it, but could you make a simple PIR sheet blank for the window?

It does open outwards. It faces north, so there's not a lot of solar gain; I've stuffed the gap between window and frame with bubble wrap, which seems to work adequately. I might move to PIR board when winter comes around.

The split was supplied with a zipped-fabric-and-velcro seal specifically for this purpose but I've not yet looked into fitting it!

Yesterday's total energy was 15.77kWh.