Timeline for How to represent kWh usage by year against average temperature?
Current License: CC BY-SA 3.0
11 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 2, 2018 at 16:56 | comment | added | EngrStudent | A theorist will look at vapor-compression cooling on a psychrometric chart and assume that the liquid condensate is at the temperature where it condensed, but it is typically a few degrees below the lowest coil temperature. Cooling that much liquid by that much is a sink. Inefficiency/entropy. Infiltration/leaks (such as people walking in the door) can be big. There are requirements about how frequently the air in the conditioned space is fully replaced by outside air. In a place like Houston, a proposition like that means you have a constant inflow of humidity with your warm N2+oxygen. | |
| Aug 1, 2018 at 16:30 | comment | added | whuber♦ | @EngrStudent Thank you again--those are all interesting points. I had no idea that humidity might account for such a large proportion of the budget. That's the kind of observation that exemplifies the potential value of coupling a good theory (or "conceptual model" in some circles) with the statistical analysis. | |
| Aug 1, 2018 at 13:57 | comment | added | EngrStudent | I love this good foundation/analysis, please hear this as applause, not criticism. The heating process is different than cooling, so the non-piecewise quadratic on both sides might be at odds with that. The evaporator coil is indoors during cooling and outdoors during heating. In heat-pump there is also defrost cycling and "back up heat". Also, the compressor has to work harder to fight against a more extreme outdoor temperature, so not only are you moving more heat, you are moving it up a higher hill. It isn't linear. Humidity is big, and can be 2/3 the energy budget. Air infiltration. | |
| Jul 31, 2018 at 21:03 | comment | added | whuber♦ | @EngrStudent All good points and much appreciated. I would maintain that the approach presented here, although simplified, shows what is needed to lay a foundation to tease out these subtler effects. Once you handle the big terms in the model--and I think nobody will deny that temperature has to be a dominant contributor to costs--then, if you have done that in a physically meaningful way, you might be able to identify other terms and perhaps even estimate their effects accurately. If you don't deal with the big terms correctly, then you haven't any hope of characterizing the others. | |
| May 23, 2017 at 12:39 | history | edited | CommunityBot |
replaced http://stackoverflow.com/ with https://stackoverflow.com/
|
|
| Jun 24, 2016 at 23:00 | history | bounty ended | Scortchi♦ | ||
| Jun 21, 2016 at 0:42 | comment | added | EngrStudent | Physics is more hairy than this. The condenser and evaporator switch roles in heating vs. cooling. This means they act like two different systems, not one continuous. Heating degree days, cooling degree days, and dehumidification degree days are three separarate cost-drivers, and depending on geographic location (think ak, wi, ca, az, mo, and fl) and year can act discontinuously (end of heating season isn't the same as start of cooling). Decent stats on the data say there are 5 seasons, not 4. May is its own season, at least within the last 5 years. | |
| Jun 17, 2016 at 20:29 | history | edited | amoeba | CC BY-SA 3.0 |
link to the SO
|
| Apr 27, 2015 at 12:27 | comment | added | Shawn | This may be the single best response to any stack overflow question I have read. I greatly appreciate the time taken to explain the logic and reasoning behind the solution. | |
| Apr 27, 2015 at 12:23 | vote | accept | Shawn | ||
| Apr 24, 2015 at 18:08 | history | answered | whuber♦ | CC BY-SA 3.0 |