COLD!

[Uncle Gump]

Exactly my point...

I think they are in pretty wide spread use in the southern states... so the load on the electrical grid doesn't change much from blowing cold to blowing hot air.

 

[Dirtman]

That's exactly what they are.

And that's what most of my colleagues in Alabama and Texas have for their heat in winter. And they work OK when it is only down to 40F at night and back up into the 60s during the day. But as Dirtman says they don't work very well in "real" cold weather, which is what they had last week. And as a result, the "A/C" system is running more than it would during 105*F.

I wouldn't think they would run AT ALL in temps below freezing. Again I know very little about heat pumps but your typical A/C unit's evaporator will ice up and stop working if you try running it in low temps.

 

[Roert42]

Strongly suspect that the power generation plants down here count on winter as 'down time' to do maintenance, and also deliberately shut parts of the plants down since demand is expected to be lower. After all no reason to run the boilers / turbines full time without demand, right?

To say that they got caught with their pants down and unprepared is overstating the obvious.

Somewhere, all the information about power draw / KW hrs is out there.

Jim, I wouldn't think that the power draw in the winter would be what it is in the summer, either, but running a heat pump 24/7 if that's all you have, I'd expect that to draw the same whether it's trying to extract heat, or cool the house. So..... just speculation on my part, power draw may have been higher than we'd think. Perhaps there's an EE on the board who would know for sure.

I know most oil refineries plan their major rebuilds, outages, ect for the middle of winter.

 

[don4331]

I know most oil refineries plan their major rebuilds, outages, ect for the middle of winter.

Only down south - up here in Canada, we drill in winter once frost is in ground, as the heavy equipment doesn't damage the roads as much. And our oil refineries due their maintenance/upgrades/etc in middle of summer

Funny, I have not issue with tripping pipe on drill rig in middle of nowhere in -40*, but the thought of doing maintenance at the battery/refinery in same weather just sends shivers down my spine.​

 

[Dirtman]

Crude oil tastes better cold.

 

[Curious Hound]

Heaters are nothing but fans, how does that compare electrical usage wise to an AC unit which has a large compressor to spin? My gas bill is more in winter but electric drops significantly even when its 10 degrees out.

Heaters are fans with resistance heating elements. Resistance heaters use lots if electricity.
When the temperature gets too low for a heat pump to work, they often have emergency resistance heater elements (commonly called emergency heat strips) that the blower fan can blow the air across to heat it. In this mode, the compressor is switched off. BUT the emergency heat strips are an OPTION when ordering a heat pump. So in temperate climates like Texas, they might not be installed in everybody’s heat pump system. At that point, you are SOL in frigid temperatures.

Purely resistive loads, like emergency heat strips use more electricity than inductive loads like motor operated compressors and fans. This is due to something called “power factor” and that gets us way deeper into electrical theory than most of you want to go. Basically, a 30amp resistive load at 240 volts = 7200watts of power used. But a 30 amp compressor with a 0.8 power factor at 240 volts = 5760watts of power used. In a nutshell, resistance heaters cost more to operate. You pay by the kilowatt-hour or how many thousands of watts you use per hour.

 

[Bill]

meanwhile back in northern Ohio,,,

I just checked my electric bill. July was the highest followed by August then September.

peak demand during severe winter storms is usually very close to summer heat waves.

Winter demand doesn't come near summer demands for electricity in Texas, Arizona, California, and many other states. The center of Ohio sits at around 40° N. The middle of Texas is roughly 30°N. If you think the sun makes your place hot in the summer in Ohio you would be overwhelmed by how much hotter it would be if you were located 10° to the south. The average July high in Columbus is about 84° whereas Dallas runs about 96° during the day and often in the upper 70s at night with higher dewpoints. In Texas people run their air conditioners day and night throughout the summer. In Ohio they have air conditioners that they run during the warmest part of the hottest days, or maybe to dehumidify when the dewpoints are higher than usual.

 

[Dirtman]

Winter demand doesn't come near summer demands for electricity in Texas, Arizona, California, and many other states. The center of Ohio sits at around 40° N. The middle of Texas is roughly 30°N. If you think the sun makes your place hot in the summer in Ohio you would be overwhelmed by how much hotter it would be if you were located 10° to the south. The average July high in Columbus is about 84° whereas Dallas runs about 96° during the day and often in the upper 70s at night with higher dewpoints. In Texas people run their air conditioners day and night throughout the summer. In Ohio they have air conditioners that they run during the warmest part of the hottest days, or maybe to dehumidify when the dewpoints are higher than usual.

Www.facebook.com

 

[Roert42]

?

 

[Bill]

?

It's Dirtman. There's no real purpose or meaning behind most of his posts. He does it so he can click on "quote" and "post reply" buttons. It adds some meaning to something for him. For the rest of us it's just a big "?"

 

[MikeG]

Average winter demand, no, not all that great on the electrical system here. Temps in the single digits and heat pumps literally running 24x7 till they freeze over? Uh, different story. Space heaters are just straight 100% consumption. Heat pumps and A/C, those transfer heat, so more efficient.

For a gas furnace with a fan, no, it doesn't use much. Just the fan. In a smaller house, probably a 110 v motor is sufficient.

A/Cs, and heat pumps, there is a reason the compressors are 220. They use a lot of power!

Heat pumps will be more efficient in cold weather if there is a ground loop below the frost line, and it runs water to transfer heat from. I'm sure it is more expensive up front, and some of this area, the majority of the dirt in your yard, came stuck to the bottom of the sod what was laid. Digging a hole, where I live, is a major proposition. So nobody does that.

 

[Uncle Gump]

?

 

[G8orFord]

It's not quite as simple as just reversing the compressor when it comes to a heat pump, but that's the basic principle. On A/C you are removing heat from the inside of the house and moving it outside, on heat you're trying to move the heat outside to the inside. While it doesn't sound too smart, it actually works quite well in normal southern conditions. The heat pump does not work very well below about 35°F but it will continue to try down to the upper 20's. Any reasonably modern unit will kick the compressor out and the heat strips in at about that temp. And yes, the condenser unit can freeze over, especially with our high humidity, but the unit will defrost itself when needed, assuming it's working properly.

 

[MikeG]

I had several friends with heat pumps report the units iced over. So it does happen.

First night in the 20s, GF's house way maybe 60F in the morning with the heat pump running all night. After that, fired up the insert in the fireplace, and kept the house around 70F the rest of the week, with the heat pump barely running at all. And, it is a fairly new unit - think she replaced it in 2019.

If a (new) heat pump working on a continuous duty cycle won't keep a house above 60F when it's 20F outside, guess how well they work in single digits.....

Gonna see if I can find any info on peak power draw for say, last Monday night, when it got down to 4F here.

 

[MikeG]

Found a couple of things, still looking.

"The current winter peak demand record is 65,915 MW set on Jan. 17, 2018 between 7 and 8 a.m. "

Extreme cold weather expected to result in record electric use in ERCOT region

News releases published by ERCOT.

www.ercot.com

"Austin, Augut 23, 2005 – The Electric Reliability Council of Texas, Inc. (ERCOT) region set a new electricity usage record of 60,279 megawatts "

ERCOT Sets New Peak Usage Record

News releases published by ERCOT.

www.ercot.com

Note the dates, but over 60,000 megawatts in both summer and winter.

Still looking for updated info.