Southern "hot" cities more energy sustainable than northern "cold" cities?

[davester]

Ted King wrote: Thanks for the informed critique of the article. Just as your seat-of-the-pance rough guess, do you think overall energy consumption for houses of equal net thermal exchange rate* between inside and out are generally greater in northern regions, less or about roughly the same as much more southernly regions? Or is there just too many unknowns for you to feel comfortable even giving a guess?

My seat of the pants guess is that they are similar. The number of heating or cooling degree days are greater in the north than the south as that article pointed out. However, it's easy to insulate and weatherstrip a house to reduce the advective and conductive heat flow so as to keep a small volume of warm air inside by adding a small amount of makeup heat using a furnace. However, it is much harder to combat the radiant, advective and conductive heat flow from the massive body of heated air and the constant summer sun beating down on the house all day. The degree day model that was used in the study, doesn't consider the effects of radiant heat from the sun, which is a large aspect of the heat load on southern homes, and does not even enter the equation for northern homes. Also note that the study states...

Sivak freely admits that he's looking here at only one small piece of the sustainability picture, which also includes things like water consumption, transportation and air quality (within the realm of heating and cooling, he also doesn't factor in the energy needed to extract the natural resources that feed power plants to provide electricity to your air conditioner). And he's not considering whether buildings in Minneapolis are better insulated than those in Miami.

.

It's also not clear from the study whether he considered the fact that running appliances and lights in a northern home contributes to keeping it warm, whereas running those same appliances and lights in a southern home (including the air conditioner!) add heat that needs to be removed by the AC.

[SteveG]

I hope I am not seeming to outsource the Right Wing Crazy, but is your next suggestion that we give Detroit to Canada?

Or that we conquer Mexico? (Tried that).

[Bill in NC]

But for heating, heat pumps are MUCH more efficient than burning fuel (boiler or forced-air furnace)

Ca Bob wrote:
Since air conditioners are, in part, heat engines (they compress a gas, allow it to cool to about ambient, and then allow it to expand, which results in cooling), the overall efficiency of an air conditioner is relatively low.

[August West]

davester wrote:
That article way overreached on the basis of a very small and limited piece of modeling. The researcher created a very simple model of energy inputs to temperature based on climate degree days at two locations, and assumed that all other factors were equal. He did not attempt to calibrate his model with real data. I do computer modeling quite often, and in my experience, an uncalibrated model is useful for...NOTHING.

Thread is useless without pictures graphs.

[davester]

August West wrote: Thread is useless without pictures graphs.

[Filliam H. Muffman]

Bill in NC wrote:
But for heating, heat pumps are MUCH more efficient than burning fuel (boiler or forced-air furnace)

I guess I somehow missed that month of material in my Thermodynamics class...

[August West]

Ahhhhhhh, satisfaction at last !!