chrisser
12-03-2007, 12:41 AM
First, let me apologize for my ignorance. I'm just beginning to learn about alternative energy...
I've been thinking lately about heat pumps, and geothermal heating.
If I understand it, heat pumps, at least as used to heat a home, use some amount of energy to extract heat from the colder, ambient outside air, and deliver it into the inside. I'm assuming for this to work that it takes less energy to "move" the heat than it would to simply use that energy to heat an electric coil and heat directlly.
Further, as I understand it, geothermal works the same way, except rather than extract heat from the cold ambient, you pull it out of the ground, which is generally warmer than ambient when you're interested in heating the house.
I would gather that the expense of geothermal is offset by it being easier to extract heat from a source that's 50-55 degrees (the ground) than from ambient which could be a lot lower temperature.
So anyhow, I noticed last winter that even on cold days, when the sun breaks through, the inside of the car, and the road surface can get significantly warmer than ambient.
It occured to me that if you had the space, you could set up some sort of large solar water (or other working fluid) grid. Perhaps a roof, or other flat black structure, with a network of pipes under a glass or plastic cover, that would absorb sunlight while insulated from ambient air, and heat the working fluid to something higher than the 50-55 of the ground - perhaps even pumping it into a large, insulated water reservoir during the day.
Could you then utilize that source for a geothermal heat pump rather than the normal well heat source and perhaps gain some additional efficiency?
Heck, taking it a step further (and discounting the probably substantial cost of collectors) what if you had a similar setup in warmer weather? Lets say a large solar collector to warm a working fluid as hot as the sun would allow, another collector right below it in the shade that would be at ambient, and then a geothermal well. Seems like, between those three heat sources, and ambient air temperature, there would always be a pair with a pretty significant heat differential. Could a modest stirling engine be used to generate small amounts of electricity off those sources? I'd bet you could get a working fluid close to 200 degrees F in the bright sun, and the ground is still going to be around 50-55. Sometimes the night air can go even colder in spring and fall.
Just kicking ideas around. Please don't hold back in pointing out where I'm misunderstanding - I'm trying to learn all I can...
I've been thinking lately about heat pumps, and geothermal heating.
If I understand it, heat pumps, at least as used to heat a home, use some amount of energy to extract heat from the colder, ambient outside air, and deliver it into the inside. I'm assuming for this to work that it takes less energy to "move" the heat than it would to simply use that energy to heat an electric coil and heat directlly.
Further, as I understand it, geothermal works the same way, except rather than extract heat from the cold ambient, you pull it out of the ground, which is generally warmer than ambient when you're interested in heating the house.
I would gather that the expense of geothermal is offset by it being easier to extract heat from a source that's 50-55 degrees (the ground) than from ambient which could be a lot lower temperature.
So anyhow, I noticed last winter that even on cold days, when the sun breaks through, the inside of the car, and the road surface can get significantly warmer than ambient.
It occured to me that if you had the space, you could set up some sort of large solar water (or other working fluid) grid. Perhaps a roof, or other flat black structure, with a network of pipes under a glass or plastic cover, that would absorb sunlight while insulated from ambient air, and heat the working fluid to something higher than the 50-55 of the ground - perhaps even pumping it into a large, insulated water reservoir during the day.
Could you then utilize that source for a geothermal heat pump rather than the normal well heat source and perhaps gain some additional efficiency?
Heck, taking it a step further (and discounting the probably substantial cost of collectors) what if you had a similar setup in warmer weather? Lets say a large solar collector to warm a working fluid as hot as the sun would allow, another collector right below it in the shade that would be at ambient, and then a geothermal well. Seems like, between those three heat sources, and ambient air temperature, there would always be a pair with a pretty significant heat differential. Could a modest stirling engine be used to generate small amounts of electricity off those sources? I'd bet you could get a working fluid close to 200 degrees F in the bright sun, and the ground is still going to be around 50-55. Sometimes the night air can go even colder in spring and fall.
Just kicking ideas around. Please don't hold back in pointing out where I'm misunderstanding - I'm trying to learn all I can...