Date: Fri, 3 Aug 2001 10:45:13 -0400
Reply-To: David Beierl <dbeierl@ATTGLOBAL.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Beierl <dbeierl@ATTGLOBAL.NET>
Subject: Re: insane AC idea
In-Reply-To: <JMEMIJLNCGJKJLLAIEGHOEMHCHAA.swade@umiacs.umd.edu>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 10:33 AM 8/3/2001, Wade Shen wrote:
>PS, there's a company called dongfar that makes a 12v 1300btu AC
>system. They claim something like 300 watts of power usage. This may be
>more doable, but I haven't ground through the math.
Usage notes from the Dongfar A/C manual:
USES
Our portable 12V/24V air-con is very useful for camping tent. In fact it
can be used for any small rooms. One of the practical functions for our
air-con is in interstate truck's sleeper cabin.
If the unit is to be used for more than 6 ft x 4 ft x 6 ft space, our
DcAircon will not be able to bring down the room temperature to 23 to 25
degrees Celsius. It will be higher than 23 to 25 degrees Celsius. However
one will still feel comfortable in the room as the humidity is lower than
the ambient air. Our air-con is not meant for rooms bigger than 6 ft x 4 ft
x 6 ft if the purpose is to bring down the room temperature. However it can
function as an equipment or device to lower the air humidity in the room.
Our DcAircon's cooling capacity is only about 1020 Btu (300 watts). For
calculation purpose, a person needs about 7.5 Btu per cu ft of space. While
asleep a person generates about 340 Btu (100 watts) of heat load.
Cars have too many windows that allow direct sunlight to pass through.
DcAircon cannot be used in a car during the day, however it can be suitable
during the night. Unless the car's windows are all screened away from the
sun, our DcAircon cannot be used in a car with a lot of windows during the
day. Our DcAircon has only 300 watts (1020Btu) cooling capacity. The
sunlight that passes through your car windows are too much for our DcAircon
to handle. A typical car's air-con has a cooling capacity of about 30,000
Btu (or 8500 watts). This is enough to cool down 5 typical rooms. The
off-coil air temperature of car air-con is about 7 degrees Celsius, while
our DcAircon is around 20 degrees Celsius. The sun has a typical intensity
of 1000 watts per square meter. So our DcAircon is not even enough to
"neutralize" the heat of the sun.
David Beierl - Providence, RI
http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"
