Just two standard double bedrooms, however one serves and mine and the wifes office space, which with two pcs, laptops and ultrawides has been getting very toasty, especially as the room is South>south East facing
Split Air con
- Thread starter YoungBlood
- Start date
Just two standard double bedrooms, however one serves and mine and the wifes office space, which with two pcs, laptops and ultrawides has been getting very toasty, especially as the room is South>south East facing
You probably won’t need to run them above low for the two rooms once you get into it - check the unit quoted is an has an inverter compressor, they can modulate their outputs.
Once you get them, the way to get the best out of them is long cycle times. It takes a shed load of energy to start up the compressor but once it’s running it will consume a modest amount of electricity.
What you don’t want is for the unit be on too high, cool the room rapidly, go past the set temperature and shut down. 20 mins later it starts up again, rinse and repeat. When people complain about energy consumption of AC, this is how they are normally using them.
Most AC tie their compressor outputs to the fan speed so sticking it on low fan speed for long periods of time is the way forward, you just want to keep it running continuously to prevent compressor shutdowns.
Once you get them, the way to get the best out of them is long cycle times. It takes a shed load of energy to start up the compressor but once it’s running it will consume a modest amount of electricity.
What you don’t want is for the unit be on too high, cool the room rapidly, go past the set temperature and shut down. 20 mins later it starts up again, rinse and repeat. When people complain about energy consumption of AC, this is how they are normally using them.
Most AC tie their compressor outputs to the fan speed so sticking it on low fan speed for long periods of time is the way forward, you just want to keep it running continuously to prevent compressor shutdowns.
Yeah, that's ideally how I want to run them. Basically just maintain an ambient temperature between the rooms throughout the day, and hoping the solar (once installed) will cover the running costs. They're not being brought in to cool / heat quickly in a pinch - I spend too long in the office (WFH) to do that.
@montymint I personally would try and get a multisplit, As I did have a single unit in the hallway and tried to cool the upstairs and you will need to use floor fans to move the cool air.
If you a large unit then you could start short cycling as B0rn2sk8 mentioned.
If you a large unit then you could start short cycling as B0rn2sk8 mentioned.
Associate
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- 24 Mar 2011
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- Cambridgeshire
One thing I would say is that compressor cycling isn't anywhere near as much of a concern with A2A systems. The horrible efficiency you get from cycling on heat pumps is mostly a problem for A2W systems.
The problem on A2W is you have a large system volume of water you need to heat every compressor start. So, when the compressor cycles you lose a lot of heat in that water - and then you need to pump a lot of energy back in before you get useful heating. On A2A you only have a couple of kilos of refrigerant and it’s being cycled around the system as a much faster rate, so compressor cycles don't have anything like the same energy loss or restart penalty. Obviously not cycling at all is still best, but the issue is an order of magnitude less problematic on A2A vs A2W.
There was a comment that compressors need a large amount of power to restart. I disagree. If you want some data on that, our system sometimes short cycles while cooling. On the compressor restart, the compressor pulls ~80% more power than normal on the restart for ~7 seconds. Following that, it actually drops to lower than usual power as it settles back to baseline power about 30 seconds later. And remember with FCUs you get useful cooling and heating within 10-15 seconds of startup (and as little as 5 seconds for very close units). There’s no huge cycling losses here.
The problem on A2W is you have a large system volume of water you need to heat every compressor start. So, when the compressor cycles you lose a lot of heat in that water - and then you need to pump a lot of energy back in before you get useful heating. On A2A you only have a couple of kilos of refrigerant and it’s being cycled around the system as a much faster rate, so compressor cycles don't have anything like the same energy loss or restart penalty. Obviously not cycling at all is still best, but the issue is an order of magnitude less problematic on A2A vs A2W.
There was a comment that compressors need a large amount of power to restart. I disagree. If you want some data on that, our system sometimes short cycles while cooling. On the compressor restart, the compressor pulls ~80% more power than normal on the restart for ~7 seconds. Following that, it actually drops to lower than usual power as it settles back to baseline power about 30 seconds later. And remember with FCUs you get useful cooling and heating within 10-15 seconds of startup (and as little as 5 seconds for very close units). There’s no huge cycling losses here.
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Excellent, I have Haier Multisplit and a single Panasonic which is 5KW.
The both have good Warranties of approx. 5 years.
I do prefer the Panasonic.
Had an issue with the Haier where I had a coil leak on one of the indoor units!
Caporegime
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- 11 Mar 2005
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- Leafy Cheshire
Installed a Mitsubishi Heavy R32 Multi Split ~4 years ago now, been really please with it and had 0 issues.
From my research years back the Mitsubishi Heavy systems are well regarded.
From my research years back the Mitsubishi Heavy systems are well regarded.
A lot of knowledge and experience on this thread, which I'm hoping will help me. I've been researching for days.
My questions are 1) how to calculate the max cooling capacity required, and 2) what temperature that capacity can get a room to?
I've used various calculators using google (search "air con calculator") and each of them gives me wildly different answers. The rooms in question are fairly large:
1. Open plan kitchen/diner, L shaped, 70sqm. 2.7m high ceiling. South facing garden. Calculators say between 7kw and 14kw.
2. 50sqm square lounge. 2.7m high ceiling. North facing. Calculators say between 6kw and 8kw.
For the kitchen, I'm considering between a Daikin 10kw single split or 2 x 6kw single split (with a unit on the kitchen side and one on the dining side).
I recently had a Bosch Climate 3200i 3.5kw system fitted to a 24sqm room with 2.7m high ceilings, south facing. All the advice and recommendations suggested 3.5kw is more than enough for that space. What I've found is that it is able to get the room from 25 to 20 relatively quickly (~30 mins). But then will never get below 20. Whilst below 20 is way too cold, I'm trying to understand why it isnt able to get below that temperature.
Any advice appreciated!
My questions are 1) how to calculate the max cooling capacity required, and 2) what temperature that capacity can get a room to?
I've used various calculators using google (search "air con calculator") and each of them gives me wildly different answers. The rooms in question are fairly large:
1. Open plan kitchen/diner, L shaped, 70sqm. 2.7m high ceiling. South facing garden. Calculators say between 7kw and 14kw.
2. 50sqm square lounge. 2.7m high ceiling. North facing. Calculators say between 6kw and 8kw.
For the kitchen, I'm considering between a Daikin 10kw single split or 2 x 6kw single split (with a unit on the kitchen side and one on the dining side).
I recently had a Bosch Climate 3200i 3.5kw system fitted to a 24sqm room with 2.7m high ceilings, south facing. All the advice and recommendations suggested 3.5kw is more than enough for that space. What I've found is that it is able to get the room from 25 to 20 relatively quickly (~30 mins). But then will never get below 20. Whilst below 20 is way too cold, I'm trying to understand why it isnt able to get below that temperature.
Any advice appreciated!