Changfa cooling

[Stevem]

Hi folks;
     I am posting this in hopes that someone might post photos of a changfa with a pressurized cooling system with pump, remote radiator fan, and battery charging capability.  Am not sure how one can power an alternator when the St head is direct coupled.  I freely admit that I am much more of a follower than an innovator on such things.  I try looking around in archives but don't have a lot of luck.  Thanks in advance.  Stevem

[Jesse McB]

Im in the middle of a project of making a pressurized cooling system for my changfa R165, using a thermostate, radiator, 12v fan, 12v water pump, and a 450 dirt bike fill side radiator. Im attaching a small mini alternator belted to the flywheel as a pully for powering the fan and water pump.  its gonna be exactly like how you are describing, i can post a diagram of my system on my thread soon, im just waiting for the parts to arrive in the mail from ebay, check out my thread! And there are quite a few members that have a pressurized cooling system for their bigger changfas! 

[Thob]

Since you have an ST connected, you can get a mains-powered battery charger that runs off the ST to charge your battery and keep the accessories powered.  Much simpler than a car alternator and doesn't require any mechanical connection.

[mobile_bob]

i am direct driving an st-7.5,  twin 110-555jho alternators and, a sanden refrigeration compressor

the unit is not in use right now, but i can get some pics of the setup, as they say a picture is worth a thousand words?

later
bob g

[mobile_bob]

i have taken some pics of my 195 trigenerator... and will upload them in a bit.

first would like to explain a bit on my design philosphy

my s195 changa was put together back in 2007, i guess it has been 10 years ago now.
i wanted a multifunction test bed to work out a number of ideas i had kicking around in my head at the time.

the unit was to power my then planned for offgrid existence and as such had to have the absolute best economy
i could get out of the unit. it had to do the following (as much as i recall now 10 years later.

1.  produce 7.5 kva of 120/240vac power, and/or  (st 7.5)
2. produce 2.8-5.6kwatts of either 24 or 48vdc charging capability (twin 110-555jho prestolite/leece neville)
3. produce my refrigeration, by driving an Air conditioner pump  (sanden compressor driving r-22)
4. produce all my domestic hot water needs. (via both cooling system and exhaust heat exchangers)

now the direct drive thing can (if you don't engineer your project well) end up trapping drive belts for other accessories such as driving an alternator.

i got around that issue by using hexagonal section drive belts, such as the AA series, which can drive from either side of the belt, in serpentine application,  my drive system has the st direct driven and the twin alternator and the sanden pump are driven by a pair of AA section belts in a serpentine fashion, the drive pully drives the belt pair on the back side and the driven components are driven on the front or inside of the belt pair... the result is i can change out a set of belt in around two minutes without breaking a sweat and a young guy probably could best that by half.

the belt wrap or contact is near 180 degree's on the alternators, around 120 for the sanden compressor and about the same for the drive pulley... under full load there is no belt slippage noticeable at all, as evidenced by no belt squeal or dusting of the belts.

now of course all of these things cannot be driven at full capacity at the same time, however all can be driven at part load all the time, or some combination at full output, some combinations part time, etc... so a control system is needed, and that control system could be the operator switching in and out, or a electronic control system, the latter of which was the direction i went.

full on electronic control allows for a certain amount of personal freedom and in my opinion higher overall efficiency, along with less stress on everything involved.

i have changed the cooling system to an enclosed system, with radiator and water pump.  i used an 87 nissan sentra radiator and electric fan, a bosch auxilliary heater pump from a volvo/mercedes/audi/ etc. and a tstat with housing from some sort of honda car i got at the local pikapart yard.  the cooling system operates at full load output within 205-214F with the heat exchanger taking the needed heat and the radiator/fan control only dumping heat when there is no domestic hot water needed or the need has been met.

the exhaust heat exchanger is in operation all the time the engine is in operation, if the domestic hot water needs have been met, the water is diverted to the radiator/fan to dump the excess heat.

the exhaust input temp at full load outpul (`8.1kwat at near sea level) is 640F and the exhaust temp leaving the exchanger is right at around 230-240F on a 70deg F ambient temp day.

the control system also has a dual rpm control of the engine, when there is no need for 60 hz (no need for 120/240 power)then the engine is brought back from 1800rpm to 1000rpm.  this rpm range will provide power for the sanden compressor or one of the twin alternators.. or the two at part load.

there are also low oil pressure shutdown as well as coolant overtemp shutdown capabilities.

at the time, there was a European company that did some exhaustive economy testing of then available marine generators
some of which had hot water production capabilities... they published a bunch of graphs and info about several gensets in the class of mine (7-11kwatt).  they reported best economy for each engine in bsfc numbers..

in testing i found that my changfa based trigenerator fit right into the middle of a pack of moderate to quite expensive commercial offerings, beating out 3 of them and coming very close to the same bsfc numbers of the top 4.

all in all, i was very pleased with the outcome of this project, it was proof that we can build units that are just as good in BSFC numbers and design to do just what it is for our personal needs, rather than having to adapt our needs to an off the shelf solution.

let me get to the pictures, and look into the archives... i think there is a world of info available to help you get some idea's

bob g

[Stevem]

Thanks All for the responses.  I will monitor the computer for any further posts on cooling ideas etc.  Mobil Bob, I think you work a little bit beyond my pay grade as far as accessories for the Changfa's  but I can sure learn a lot from your endeavors.  I intend to take my Listeroid out of service and run the Changfa for our backup in the next month or so.  Had I only built my slab and generator shed a few feet larger I could have both in and operating as backups for each other.  Thank you all again and I will continue to learn to negotiate my way around the archives so I don't have to ask so many questions.

[mobile_bob]

here is a poor picture, you can see one of the alternators, the sanden compressor above, the other alternator is on the other side in the same relative position.

i have some better pictures and some drawings in my archives somewhere, soon as i get some time to dig them up i will post them again.

bob g

[Stevem]

Gadzooks Mobil Bob!  I have seen time machines that were less involved!  I stared at my laptop for a full 30 seconds before i turned it sideways to orient it.  I will need a day or two to digest this.  Seriously, I was amazed at the stuff you have incorporated into this machine.  I would love to see some other photos as you get a chance to post them. 
     I am dying to get my changfa set up to replace my Listeroid this spring.  I am a believer that you are the go to guy on pressurized cooling for maximum output and I will start my quest for radiator, pump and sensors/switches.  Thanks for your help and I am truly awed by your setup.  Stevem