Inverter (LG) Energy saving conditions

[kevbo]

Can anyone tell me if there is any energy savings during operation when the unit has NOT reached the target tempreture set on the remote control. I have a LG inverter type and am wondering if the inverter technology is actually benefiting me at all. Can you tell when the unit is running on lower power? I am using the heat pump at the moment. Brings the tempreture up from 13 degress to 18 degrees but it cant raise it anymore than that it seems. So having my remote set too 24 degrees is useless right?

Thanks

[hendrag]

In normal conditions the compressor is controlled by comparing the indoor unit return air thermistor with the set point temperature on the infra red controller the bigger the difference the faster the speed. When the inverter is flat out more than 3 degrees diffference there will be no energy saving over a fixed speed compressor but when the inverter slows there is significant energy saving to be had. Typically in the uk the unit will only run flat out for 10% of the time so inverters are a really good idea but it is very application specific. the secret with inverters is to size them properley if you oversize the unit its useless as they wont run at less than 30% capacity so they have to cycle meaning inefficencies and if they are too small they operate at 100% so no saving either.

to measure what the inverter is doing
use a normal multi meter which is capable of measuring frequency (Hz) and an Amp clamp placed round one of the compressor wires. Set the meter to mA and the frequency will show on the screen. the current will fall as the compressor speed falls. if you dont have the tools listen carefully to the outdoor unit you can hear the compressor speed changing

there have been very few studies to prove how effient inverters really are so you get silly claims from manufactureres like us (and all the others) saying you can save up to 70% etc dont believe all the lies you are told. Apply the system right and use it sensibly dont set it to 30 degrees then 16 and back again leave the settings alone and you will enjoy energy efficent operation.

hope this all helps

regards

Hendrag General Manager LG aircon UK

[kevbo]

Thanks for the great reply. 2 things I would like to clarify:

1. Not sure I understand the logic that determines the compressor speed. Is it the tempreture of the air emmited by the indoor unit compared to the tempreture on the remote control? If so, the actual room tempreture is not taken into account?
2. Why when my remote is set to 24 degrees celcius(and the current room tempreture is 18 degrees celcius) and I lower the tempreture by one degree the unit starts cycling on and off. I would think that it would just slow the compressor down?

Thanks Again

[p_p]

The compressor speed is determined by the temp setting on the remote & the return air thermistor as Hendrag stated not the air off.
Inverter heat pumps are more efficient in heat mode than cooling mode so if yours is not doing the duty required I would suggest it has not been sized correctly or there's another problem with the unit somewhere.
Check unit is sized correctly, refrigerant charge, resistance of thermistors at a set temp etc.
Is there any history with the unit or are you the only one to have worked on this system

regards

PP

[kevbo]

The compressor speed is determined by the temp setting on the remote & the return air thermistor as Hendrag stated not the air off.
Inverter heat pumps are more efficient in heat mode than cooling mode so if yours is not doing the duty required I would suggest it has not been sized correctly or there's another problem with the unit somewhere.
Check unit is sized correctly, refrigerant charge, resistance of thermistors at a set temp etc.
Is there any history with the unit or are you the only one to have worked on this system

regards

PP

Sorry if I wasnt clear. The unit is working very well. Just trying to understand how it determines at what speed to run so that I can use it more efficiently by setting the tempreture on the remote to a senceable figure. Sorry but "return air thermistor" and "air off" are not layman terms to me :)

[Thermatech]

Some of the High quality inverter split systems work like VRF systems & also monitor indoor coil temp & calculate a super heat. The unit has a target SH & when it gets to target starts to reduce compressor speed even if the room temp is still not at terget.
This makes better efficiency.

[Karl Hofmann]

One issue that you can have with a high wall unit is that heat rises, so that when the upper part of the room where the unit is has reached the target temperature, the lower part where you and the hand set with the thermostat that you are reading is still several degrees cooler, so you have to allow for that when you tap in your set temperature

[karnot_cycle]

hello guys, i'm not sure if i posted my query on the right thread, just thought that this is somehow related to the subject... anyways, i plan to install an air conditioner with a cooling capacity of around 30,000 BTU/hr in a small restaurant, area would be around 45 to 50 sqm. do you really recommend the use of an inverter airconditioner? thanks in advance

[momo]

K_C: please where is "PH"? For a restaurant it depends on the type of heatloads and machines you have and expect to use: people, fridges, lighting... and cassetes, duct ... more details would help!

[karnot_cycle]

K_C: please where is "PH"? For a restaurant it depends on the type of heatloads and machines you have and expect to use: people, fridges, lighting... and cassetes, duct ... more details would help!

thanks for your reply momo, PH stands for philippines

since the kitchen will be fully enclosed, so basically heat load coming from it will not affect the dining area very much. as for the dining area, it can accomodate around 50 to 60 persons, insulation is average, there is also a little exposure to sunlight since it is not located inside a mall. i guess i'll be putting up 1 chiller also in the dining area, all heating equipments will be placed inside the kitchen. i just plan to install a wall mount split type aircon..

based on my area requirements and other heat load factors, i'll be needing around 30,000 BTU/hr of cooling capacity. what concerns me most here is, should i use an inverter type or non-inverter type?

i read some articles regarding how energy efficient an inverter type aircon is compared to non-inverter types, however, some conditions will still apply for that to happen.. so i'm asking you guys based on your experience, is it justifiable for me to use inverter type? and, will the savings be significant for my application? thanks again