AC manufacturer Greencore has come up with a long-awaited solution to the inherent problem in solar-powered air conditioning units-solar panels are still not efficient enough to power the energy-gobbling machines on their own. The company's 10200 model uses a single 170-watt solar panel during the day and electricity from the power grid during the night to charge its batteries, leading to massive energy savings even if the solution isn't 100% solar. Greencore has three versions of its AC system, a fixed one, a portable one with two batteries and another portable with four batteries. All three run on 24 volts DC and have a cooling capacity of 10,200 BTUs and a heating capacity of 13,400 BTUs. According to the company, McDonalds and the US Navy are already on board with testing the units. [Treehugger]
It's an intriguing design. By powering the air conditioner with the solar panel's DC output it avoids some losses in powering it from 220V AC. And you reduce your electricity consumption by a few kWh at peak times on hot days without having to pay for a grid-tied inverter and its losses in turning the solar panel's DC output into 220V AC. Distributed power generation where it's needed is good.
BUT. GreenCore acknowledges a 170W solar panel can't run this when its 980W compressor is cycling, then confuses the situation with grid power backup, battery storage, and night-time recharging from the grid. More complex and expensive makes those "massive energy savings" vanish. AND the solar panel goes unused in the winter. SO I think most consumers would be be better off putting solar panels on the roof tied to the power grid.
I want a future where all my appliances are USB-powered gadgets run off a bank of DC solar panels. Brando USB and Greenplug should collaborate on the "Solar USB" geek home of the future.