Solar Air Conditioner

[Opusdei]

Hello, I'm new to the forum. I would like to run my business idea by the solar enthusiastic. Currently I am developing a 12V DC air conditioner for RV and trucks. It has 6000 BTU of cooling power, 300W-795W power consumption, and rated current of 25A-66A. 12V LiFePO4 300Ah battery can sustain more than 8 hour operation. While trickle charged by (2) 200W mono panels, vehicle's alternator can fully charge the battery while driving. I would appreciate if you share your thoughts and feedback. Thanks!

 

[gnubie]

Several commercial products already exist and are mass manufactured in 'low cost' countries already. If you think you can swim in that pool, don't forget your floaties.

 

[Opusdei]

Included is temperature time profile of the 12V DC air conditioner. Compressor fan has been mounted on the rooftop of my minivan and temperature was captured by data logger. It was very hot summer day, temperature reached above 100F (blue curve). Next day I measured it again (orange curve and see the arrow region indicating air conditioner turned on). AGM batteries with 170Ah maintained the operation more than 7 hours with the help of the additional 20Ah solar charging from (2) 200W mono panels. Temperature was set to 20C (68F) and the actual temperature stayed around 70F (arrow region). Air conditioner could have been turned on and off but I could not captured the moment. It worked great!

 

[Opusdei]

That's right, similar products exist already in other markets. But they are expensive and not very efficient because they rely on the inverter. Hours of operation can be extended by the 12V DC air conditioner.

 

[chrisski]

Looking for DC appliances for my RV, I came to the conclusion that low volts push too many amps for a 12 volt or 24 volt system to effectively run a 1000 watt or 2000 watt appliance off of low voltage DC. I found a reference to a standard in development for a 300+ volt, but never found anything else on that. I’m not sure of a wire size requirement for 800 watts at 12 volts, but I’m guessing its 4 gauge or thicker.

I think am starting to understand why Edison lost in the DC / AC battle in the early days of electricity as a power source.

I’ve looked at DC air conditioners, but of the ones I found commercially available, I would be the first one on my block to get it, and I’m not that brave because of technical support.

 

[Opusdei]

Thanks for your quick remark! I am glad to join the forum.

 

[Craig]

I think it is a great Idea 24 Volt system would probably be better for my needs but Im sure a 12 could be made to work. My use would be in a Tiny house so I could even add more panels to keep it running longer.

 

[gnubie]

That's right, similar products exist already in other markets. But they are expensive and not very efficient because they rely on the inverter. Hours of operation can be extended by the 12V DC air conditioner.

No, these are DC input devices with DC motors. Admittedly the DC motors may be driven by a VFD like arrangement and that can be referred to as an inverter style, but that's more about compressor / fan motor speed control rather than source voltage conversion.

All the usual places have listings for them. I'm not trying to dissuade you from doing it, just making sure you realise that it's already an existing and competitive market.

 

[Opusdei]

That's right, inverter style air conditioner relies on the variable frequency drive technology. Since the most vehicles run on 12V DC battery here in US, we need a 12V DC air conditioner.

 

[gnubie]

I suspect you aren't quite understanding. That's OK. As I said I wasn't trying to dissuade you, only make you aware that you are entering an already crowded market. If you burn up all your money fighting China, that's OK by me.

 

[Opusdei]

I wish I can continue discussion in the other forum. It could fail, but feedback can give me a pivot.

 

[Dzl]

I suspect you aren't quite understanding. That's OK. As I said I wasn't trying to dissuade you, only make you aware that you are entering an already crowded market. If you burn up all your money fighting China, that's OK by me.

I wouldn't quite call it crowded (unless I'm unaware of some companies--which is probable) but there would be competition. However at least some of these companies (Hotspot Energy) only offers 48v DC.

That said, I hope @Opusdei is successful in bringing a product to market, competition and consumer interest can bring prices down (like we are seeing with DC compressor fridges right now I think).

@Opusdei Efficeincy would be super important I think, at least for me the biggest selling point would be avoiding inverter inefficiency and inverter idle consumption, but to maintain that efficiency advantage the A/C would have to be comparably efficient to a conventional mini split.

I would like to see a 12v/24v model, like most DC fridges, would this be possible?

 

[Opusdei]

12V/24V model exists in the market. I think @gnubie made a right point about world market. However, that is not the case for US market. As @Dzl said, some company offers 48V DC air conditioner, but that is for the household application. If we need to install a ductless mini-split air conditioner on vehicles, it has got to be 12V DC. My business model is based on OEM at factory in China and developing 12V model for the RV and trucks. I have already developed a prototype and mounted on my minivan (see a picture of the prototype and test data above)

 

[Freep]

I am able to run my coleman air conditioner in my truck camper from my LiFePo4 battery(271ah) using an inverter, of course. But when the compressor is running I'm using about 80amps of 12v. I have looked at mini split which could conceivably shave that down to a 50 amp draw.

How many cubic feet are you planning to cool? What is your target amp draw with the compressor running?

 

[Deleted-User]

So I recently broke down and bought a Massimo E-kooler (essentially a rebranded Alpicool) due to decent reviews, and I have to say, I'm impressed! It definitely chills very fast (close to freezing in about 45 minutes) and is very efficient, running at about 45 watts. Compressor was originally advertised as LG, but reports from folks tearing into the unit reveal a HuaJun ZH25G compressor (said to be a Danfoss knockoff), which quietly runs on 12 or 24 volts. Mind you, this is NOT an air producing cooler, it works by surrounding the cooler walls with the chill coils. The point of my shaggy dog story: 12-24 V compressors not only exist, are quiet and efficient (this cooler could run 7 days on my Valence XP battery, for example), but I think could be easily adapted to an A/C scenario. Even if the goal isn't to raise a compartment airspace to a certain temperature, having cool air directly blowing on your body on a hot day is still a luxury.

A bit more on the Massimo e-kooler: https://diysolarforum.com/threads/12-24v-fridge-opinions.10189/

 

[powerwagon]

12V/24V model exists in the market. I think @gnubie made a right point about world market. However, that is not the case for US market. As @Dzl said, some company offers 48V DC air conditioner, but that is for the household application. If we need to install a ductless mini-split air conditioner on vehicles, it has got to be 12V DC. My business model is based on OEM at factory in China and developing 12V model for the RV and trucks. I have already developed a prototype and mounted on my minivan (see a picture of the prototype and test data above)

i am on board with this design.

i can mount all of this in my pickup truck bed, and i already have plans to mount 400w solar above the bed on a rack. and lithium bank in the bed as well.

what i want to see is the coil set and the interior cooling unit. i have cab access, but i am not cutting a hole in the roof of my powerwagon.

 

[powerwagon]

i already have the zero breeze mark 2, and speaking to rigidDC air conditioner team.

 

[Deleted-User]

i already have the zero breeze mark 2, and speaking to rigidDC air conditioner team.

I hereby coin the term: super-mini-split

 

[Trukinbear]

From what I understand the automotive industry is as we speak considering a move to 24 or 36 volt systems due to all the electronics in cars now.

 

[svetz]

... expensive and not very efficient ...

Any ideas yet as to what the $/BTU or the watts/BTU would be?