Stirlingengineforum.com

My idea is to use the excess heat from the hot side of a stirling engine to run and absorption ammonia cooler like the propane frig in a rv.When you add a water pump it takes energy from the engine but this just uses the wasted heat and gives really cold temperatures.The more heat you add to the hot side the colder the cold side would become up to a point.

Interesting idea.

Could you still employ the water cooling and also have a secondary cooler/heat exchanger sourced from the refrigerant. (a 2 stage cooling cycle). As long as your refrigerator heat is sourced entirely from unusable exhaust heat then it can only be a gain...

I realise you are also trying to remove the losses from pumping water, but you could possibly move the water for 'free' using a thermo-syphon setup.

vamoose

Ya Vamoose,that could really give you a cold side.Another thing I thought might work is using evaporative cooling.Ive seen alot of designs using a fan as a flywheel.If you reversed the blade it would blow on its self through a wicking pad and give you an evaporative cooler.I think this would still be less of a drain on the engine than using a water pump.

My system (see my gallery, second engine), uses a radiator made with a copper top and bottom tank, joined with a matrix of 16 flat copper tubes removed from a car heater radiator, this works quite well as a normal thermosyphon system, and is improved with the addition of a low wattage fan from a computor, this is driven by tapping off some power from the generator fitted to the engine. I have no temperature recordings, but without the fan, I can only hold the water-jacket for a few seconds before it becomes uncomfortable, and with the fan, the water-jacket can be held easily for as long as the motor runs. Further improvement (temperature wise)could be gained by adding a pump, but I don't think the gain would excede the loss of the drive from the motor. Ian S C

Ian sc, the radiator and thermosyphon really look like a good setup.If I understand stirling heat engines ,it isnt how hot you get them but temperature difference between the hot side and cold side.Anything and everything you can do to increase this difference is good as long as it doesnt cost the engine as a power load.In fact I think ,you could use passive solar as your heat source if you also heated the absorption cooler with solar.your thermosyphon and radiator as precooler.Wouldnt this really increase power output? Iam aware the engine is getting pretty complex at this point but if you built it yourself you would know its weak points,and how to fix them.