Portable split air to air

TroubledTarts

As I sit here with the outside temp of 15oC with the strongest fan pulling that coolness into the vaulter kitchen diner living room (down from 25.5 to 22.1oC in the last 45 mins. Remembering without an air con unit on hot days this relief is temporary and it ramps up constantly during the day until it gets to approx 30oC (no need to pre warm the hot honey temp)

I think it's a mix of good practice windows open when the sun in down and close and covered when it's up letting the air con help all the way.

It seems you can put a cost on being comfortable during a heatwave. (Still calculating ours)

Not so unsurprisingly the days you most want the cooling facility running are the days with good to very good solar generation so the two cancel each other out in that regard. (Export payments aside for those with an export mpan) And on Agile sometimes a negative day or two thrown in for good measure to offset costs is welcomed.

tfhnota

If you have a large solar array but limited export by the DNO then running an air-conditioner when it is sunny must be the perfect match

Martyn1981

https://forums.moneysavingexpert.com/discussion/comment/82051222#Comment_82051222

Spot on.

In order for me to go bigger on my PV, but remain within DNO limits, I added DC side batts. That way, so long as I've force discharged the batts enough, I can be generating 5kW to 6kW for many hours, and exporting at the 3.68kW limit. This combo enabled me to add another 3kWp to my existing systems, and the steep south facing ground mount, that I'd wanted for a decade, to boost winter generation.

As my 3.68kW inverter (with 6.725kWp of PV) monitors export, it can mean it starts to restrict throughput as my W side PV ramps up, maybe ramping down to ~2.5kW and filling fast(er). But with the A/C consuming some energy, that will help, or I pop the BEV on to charge at ~1kW. This prevents generation clipping. [Sorry if that doesn't make much sense.]

And just a thought/note on A/C and PV in general as Troubled Tart mentioned, the two correlate almost perfectly. So nationally, you don't necessarily need to have PV, your A/C unit will be consuming energy, when the UK fleet of PV (demand and grid side generation) is also chucking out loads.

QrizB

I see there's another hot spell in the coming week, temperatures forecast to be in the 30s here. We'll see if it gets hot enough that I turn the a/c back on!

tfhnota

Overnight temp is low where I am, surprisingly, and peak daytime less than 30 - that is not super hot it is just a UK summer, no need for AC just close off the south facing windows with something reflective (insulated. velcro-on, "mats" are available on Temu for loose change) and open the windows only when the temp drops.

QrizB

The forecast highs for the coming week are 29/31/31/34/33/33/32 so we're back to hot weather mode in the QrizB house.

(My youngest is back from a fortnight in Portugal and was complaining last night that it was cold - we'll see how they like it here!)

Screwdriva

"(Single-hose units typically get a SEER and SCOP of around 2.5, for comparison. Here's an example (link) that both heats and cools; it claims an EER of 2.6 and a COP of 2.4.)"

We own a Delonghi PAC EX100. I believe it is still the most efficient portable Aircon sold in the UK - Officially rated at 3.6 EER, I have measured consumption just below 650 Watts per hour.

(Delonghi sells the PAC EX105A+++ in the EU but not yet in the UK - it is rated at 4.1 EER and consumes an incredibly low ~550 Watts to cool the same 10000 BTUs)

We paid £500 for ours ~5 years ago and it is really earning its keep this year. We've installed a hose insulation blanket to reduce the heat emissions, which has helped efficiency and noise levels slightly.

I am curious what the actual hourly consumption of the portasplit is in Watts? I appreciate it does solve the biggest weakest of a portable air-con (negative pressure environment created in the room, sucking in warmer air) but I wonder if I would have purchased one instead or if I would have gone with the lower purchase price and running costs of the EX100.

QrizB

I am curious what the actual hourly consumption of the portasplit is in Watts?

That's a good question.

It has inverter drive so the power consumption varies depending on load.

The lowest power consumption I've seen in cooling mode on my uncalibrated, uncertified ZigBee smart plug is about 360 watts. But I've also seen it up around 1200 watts for a while when it was 35C outside and I was asking it to cool to 20C.

Or, looked at from another angle, yesterday it ran from about 0800 to 2200 and used 6.5kWh. That's a bit less than 500 watts on average, on a day that peaked at 32C here. During that time, my indoor temperatures were generally in the 23-24C range (reached 25C while we were cooking, and also overnight when the aircon was off and the windows open).

For a 12000 BTU (approx 3.5kW) nominal capacity unit being asked to cool most of a 3-bed semi, I think that's pretty good.

Also, note thst energy label EERs and COPs aren't calculated the same way for splits as they are for ducted systems. Splits use a synthetic seasonal average, based on a weighted distribution of outdoor temperatures. Twin ducted systems run at a constant indoor and outdoor temperature, while single ducted systems are based on a single indoor temperature.

All the details are in Annex VII here if you want to get into them:

https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:02011R0626-20230930#anx_VII

Edit to add: I see that the Delonghi PAC EX100 is a R290 system, which is potentially more efficient than R32. That gives you an edge over most current portable aircons, including mine which is R32.

NedS

Edit to add: I see that the Delonghi PAC EX100 is a R290 system, which is potentially more efficient than R32. That gives you an edge over most current portable aircons, including mine which is R32.

That surprised me given how R290 ASHPs are not allowed to be installed near windows or air vents to prevent propane from entering the house should it leak, yet they can happily sell R290 AC units designed to sit inside the house.

QrizB

... yet they can happily sell R290 AC units designed to sit inside the house.

I'm pretty sure they come with warnings of the minimum room size you should use them in, judges to reduce the risk of an explosive atmosphere.

Full-house ASHPs are usually higher capacity and contain more R290 (which is a relatively pure grade of propane, for anyone unaware).