We are off-grid with a 2kw solar and 500w (rarely!) wind system. We are in the Upper Hunter valley NSW where it gets fairly hot in summer. I'm looking at putting A/C in our bedroom which will only be run during the day when I'm asleep (when working nightshift). Can anyone point me to a super efficient A/C?
Efficient air conditioning
(8 posts) (7 voices)-
PeterReefman
MemberWe use a 2.5kW Mitsubishi MSZ-FB25VA. Works well. I should say we only use it for heating, as the climate here is cool enough and our house is efficient enough not to use cooling mode. http://www.mitsubishielectric.com.au/2319.htm
Cheers
Posted Tuesday 7 Feb 2012 @ 11:36:21 am from IP # -
Benny
MemberWe have the Mitsubishi hyper inverter too. Only 500W consumption and COP > 5. As Peter advised check out the energy rating site and as other blogs have shown, select a small unit for optimum COP. We also use our ceiling fan when AC is on and can run it at 27C and it still feels nice and cool.
Posted Tuesday 7 Feb 2012 @ 12:08:31 pm from IP # -
Sunshine
MemberHave a look at all appliances here showing efficency comparisons.
http://www.energyrating.gov.au/compare-products/
I have recently seen advertising for solar airconditioners which claim to use 55% less power than normal splits. I don't know much about them though.Posted Tuesday 7 Feb 2012 @ 12:14:45 pm from IP # -
wlb
MemberOne trick to use with a small split inverter unit is cool the house naturally as much as possible during the night then set the therostat for 1 or 2 degrees below room temperature in the morning. The aircon will then work at low output (and power consumption because the load is small, but as the house starts to warm during the day, it has to work harder, but that coincides with more sunlight on the PVs.
An off-grid consultant friend in the US does this for his whole house using a Sanyo inverter designed for a single room. Sanyo has checked it out and approved this theoretical undersizing of their unit.
The house is well insulated, and he does track his arrays.
Posted Friday 10 Feb 2012 @ 1:37:08 am from IP # -
alfresco24
MemberBenny, where did you get the COP >5 figure for your a/c?
I havent seen this figure published by any manufacturer, with max claimed numbers topping out around the mid 4's
But, that's a number derived from 'standard conditions' and only useful for comparative purposes - up to a point. In almost all cases the high COP/EER number is only reached when the systems are running at near peak power. When running at low power, i.e. maintaining a temperature, the EER/COP decreases dramatically. In other words the COP quoted in a brochure is not representative of nominal performance, and generally the low cost versions (of all brands) derate more deeply than you might think.
I believe it's fair to say Mitsubishi and Daikin have some of the best premium products available at the moment.Posted Tuesday 14 Feb 2012 @ 1:19:19 am from IP # -
abdulla
Memberguys , i have a problem , i'm working on my senior project for mechanical engineering , and i need a shell and tube heat exhchanger of 25 cm diameter and containing 250 tubes of 6 mm diameter .
the heat transfer will be between exhause gases of the car and water , however water will have really low flow rate (0.54 l/min) and pressure of 6 bars , so i'm finding it hard to make water enter the 250 tubes in equal values , i'm just afraid that it enters from only one tube and leave from other side .
can anyone help me in a way to let water be distributed equally in tubes or if it's better to put water in shell side , thank you
Posted Tuesday 14 Feb 2012 @ 9:44:16 am from IP # -
Benny
MemberAlfresco - I'm just quoting from the energy rating site and the energy rating labels that came with the system. Am I being naive (-;
I understand what you say about the efficiency decreasing when they don't operate at full power.
The energy label that came with my AC states
cooling: input 0.49kW capacity 2.55kW ratio = 5.2
heating: input 0.60kW capacity 3.13kW ratio = 5.2One thing that puzzles me on the labels is that they also quote heating capacity at 2degC and its always higher than the main rating, 3.79kW in this case. Does this mean the main rating is calculated at a lower outside temp ?
Posted Tuesday 14 Feb 2012 @ 1:40:47 pm from IP #
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