Do DC (direct current) air conditioners exist? [yes, they do exist]
UPDATED: 2011.06.16 added a new DC air conditioner producer…
Recently I wrote about air-conditioning in off the grid environments. The approach I outlined uses solar panels which output DC [direct current]) and an inverter to convert to AC [alternating current] which runs a conventional air-conditioner.
A commenter on twitter asked the reasonable question, what about using a DC air-conditioner instead? This is actually a great idea as it reduces the need for a heavy duty inverter and it also would be more efficient (my understanding is that the best inverters are generally only about 92-94% efficient).
I didn’t recall ever seeing a direct current air conditioner, but a bit of research turned up some results:
Some of these may actually be the same models just resold under different brand names. The first one and the last link both appear to be meant for heavy-duty applications (such as trains or storage containers) and may be cost-prohibitive for most homeowners:
DIY DC air conditioner?
It would likely also be possible to convert an AC air conditioner by replacing the compressor with a DC compressor. However, I will leave the application of this technique to the reader. 🙂
Other obstacles to using a DC air conditioner?
One problem I would encounter if using a DC air conditioner (at 24 volts) would be the large wire size required for that many amps (30-50amps) over the long run between my DC batteries and my house (100+ ft) to avoid voltage drop. Whereas with AC at 110V (it would only be 6-9 amps) most normal wiring would suffice.
It was a bit of a loaded question ;). From a system simplicity standpoint, eliminating the inverter is a good thing. However from an efficiency standpoint there are several variables to consider (line length, AC loss vs DC loss, AC motor efficiency vs DC motor efficiency, etc.). Most likely it is a wash, and then you go with what is easiest (use an inverter).
i am living in an area where the temperature reaches 52 C. can your DC aircon run comfortably within this temp.? and for how long is it covered with warranty? and work with how much power?