3 ms·

Id love to see a combined heat and power system that burns natural gas to drive a heat pump compressor, and recovers the combustion heat. I wonder what multipli

Id love to see a combined heat and power system that burns natural gas to drive a heat pump compressor, and recovers the combustion heat. I wonder what multiplier it would get on a therm.

nanomonkey 4y ago
I've been contemplating the same thing. Something like the WhisperGen stirling engine hot water heater should be available to everyone. Hell even a water cooled honda generator that runs off natural gas, and pumps the radiator fluid into your home for heating purposes would be nice. It seems weird that we aren't producing electricity when ever you burn natural gas for heating.
- lazide 4y ago
  The issue is maintenance and capital expense due to complexity. Gas furnaces are dead simple, and still break and require maintenance. Heat pumps, more so. Generators? By far the most. Combining the three sounds like a huge headache for marginal efficiency gains.
  - nanomonkey 4y ago
    This is why I started off referencing external combustion engines like Stirling engines. These tend to have very low maintenance needs as the combustion occurs outside of the pistons, so there is no fouling of the moving parts. One could use self lubricating materials like graphite rods as your piston heads and have quite high reliable components. The stirling engines that NASA utilizes are considered maintenance free. As far as efficiency gains, we're talking 25-40% of the energy being produced as electricity and the majority of the rest being turned into hot water for residential use, either by one household or a whole city block. This doesn't sound like a terribly marginal gain. Specially if the energy production is done during the hours when traditional solar installations are not producing which are generally when folks are running their heating.
- maxerickson 4y ago
  Generators with heat recovery exist, search on micro CHP.
  - nanomonkey 4y ago
    Yes thanks, I'm aware. I have actually worked in this field in the past building wood gasification micro CHP units.
mindslight 4y ago
There are refrigerators that run directly off of propane. https://www.ferrellgas.com/tank-talk/blog-articles/how-propane-powers-refrigeration/ https://www.ferrellgas.com/tank-talk/blog-articles/how-propa... The working temperatures of ammonia are probably wrong for a heat pump, but perhaps something similar could be devised.

Id love to see a combined heat and power system that burns natural gas to drive a heat pump compressor, and recovers the combustion heat. I wonder what multiplier it would get on a therm.

nanomonkey 4y ago

I've been contemplating the same thing. Something like the WhisperGen stirling engine hot water heater should be available to everyone. Hell even a water cooled honda generator that runs off natural gas, and pumps the radiator fluid into your home for heating purposes would be nice. It seems weird that we aren't producing electricity when ever you burn natural gas for heating.

lazide 4y ago
The issue is maintenance and capital expense due to complexity. Gas furnaces are dead simple, and still break and require maintenance. Heat pumps, more so. Generators? By far the most. Combining the three sounds like a huge headache for marginal efficiency gains.
- nanomonkey 4y ago
  This is why I started off referencing external combustion engines like Stirling engines. These tend to have very low maintenance needs as the combustion occurs outside of the pistons, so there is no fouling of the moving parts. One could use self lubricating materials like graphite rods as your piston heads and have quite high reliable components. The stirling engines that NASA utilizes are considered maintenance free. As far as efficiency gains, we're talking 25-40% of the energy being produced as electricity and the majority of the rest being turned into hot water for residential use, either by one household or a whole city block. This doesn't sound like a terribly marginal gain. Specially if the energy production is done during the hours when traditional solar installations are not producing which are generally when folks are running their heating.
maxerickson 4y ago
Generators with heat recovery exist, search on micro CHP.
- nanomonkey 4y ago
  Yes thanks, I'm aware. I have actually worked in this field in the past building wood gasification micro CHP units.

mindslight 4y ago

There are refrigerators that run directly off of propane. https://www.ferrellgas.com/tank-talk/blog-articles/how-propane-powers-refrigeration/ https://www.ferrellgas.com/tank-talk/blog-articles/how-propa... The working temperatures of ammonia are probably wrong for a heat pump, but perhaps something similar could be devised.