This highly informative video by Bruce Ritchey, CEO of WaterFurnace International, details how geothermal heat pumps can be used to heat and cool homes. Not only is the cost less than with conventional systems, the systems are quiet, environmentally friendly, and require less maintenance.
These heat pumps use the stable temperature of the earth a few feet underground to store heat in the summer and use it in the winter. Thus, the energy to heat and cool the home comes from the earth itself, something which has obvious huge potential, especially in the Northeast where heating oil is becoming extremely expensive.
Um, let me ask a question I haven’t heard asked as yet: what is the Earth’s capacity for absorbing all this heat? Let’s say ten million people in the Los Angeles basin begin cooling with geothermal. Sure, it would save a lot of energy. But will that not raise the temperature of the local ground? And as that temperature changes, would we not also expect expansion and/or contraction– the very forces that cause earthquakes in that fault-ridden area? Call me a skeptic, but I doubt there’s a free lunch here– at least not for all 6 billion of the planet’s residents.
Well no one said it would be for six billion! But Iceland already gets much of their heat from geothermal, and I assume some of that would be geothermal pumps, and they’re doing fine.
DJ,
Considering that most geothermal systems use no more than the top 150′ – 200′ of the Earth’s surface (we are talking about only a very small area like 20′ X 20′ surface area for one house – horizontal loops only go down 6′ and cover an area about 2′ X 400′). The heat that you put in the ground is quickly absorbed by the ground and dissapated, not to mention that we are talking about 90 degrees. The energy from the Sun penetrates much deeper than that, you couldn’t possibly deposit more heat than the Sun does.
I’ll admit that I flunked Calc 2 twice so I can’t do the actual calculation, but I’ll make a stab at an estimate. Lets say it takes 48,000 BTUs to cool an average home in the Los Angeles basin, and there are roughly 4 million homes, and roughly 3/4 of the days require cooling at a conservative six hours a day. That would be in the ballpark of 80 billion BTUs per year. Plus there are literally billions of square feet of commercial space, most of which require cooling.
With geothermal, all that heat would go into the earth’s crust. You say it “dissipates” quickly, but it has to go somewhere– either up (into the atmosphere, raising the local temperatures) or down (deeper into the earth’s crust).
I’m not saying that’s more heat than the earth gets from the sun, but it is certainly ADDITIONAL heat that the earth wouldn’t have gotten otherwise– and concentrated in a small area that is literally riddled with earthquake faults. That doesn’t worry you?
DJ,
I think the point that you are missing is the system is not manufacturing heat, it is moving the heat that already exists from one location to another. It has been a very long time since I took calculus but I suspect that if you calculate the amount of BTUs being absorbed by the Earth from the Sun, the amount going into the ground by geothermal systems even if everybody used them is such a minute amount that it would not be noticeable.
Remember your thermodynamics. Heat goes to cold, so any heat energy you put in the ground dissipates to colder ground and not to the air.
Geothermal can’t be used by all because it requires open land to put the pipes in. So it probably won’t work in mass scale in cities. But in the Northeast where people badly need alternatives to heating oil it might well help some.
The pipes are quite shallow, so can’t see how this would have much of a major effect on heating or earthquake possibilities.
Bob,
That isn’t necessarily true regarding the need for open land. There are horizontal boring techniques that allow for the pipes to go in under houses or even under streets. The best thing that you can say is where there is a will, there is a way.