07-07-2022, 10:33 PM
(01-31-2022, 12:10 PM)KevinT Wrote:(12-27-2021, 09:45 PM)EdM Wrote: A bit off topic, but with newer technology it's possible to have a 2-pipe system switch to heating over night and cooling during the day. Here's an article on a school retrofit: Two-Pipe HVAC Makes a Comeback: An Idea Discarded Decades Ago May Be the Future of School Heating and Cooling.
"Changeover can be accomplished with very little loss of energy in 20 minutes with no human intervention whatever."
That link was stellar, thank you!
It’s hard to imagine that’s really needed. If a building starts comfortable or slightly cool in the morning, high daytime temperatures will not normally make it uncomfortable by the end of the day except in unusual situations (e.g. poor design with massive solar gain, or a room with a massive brick oven). So it should be enough to ventilate overnight, if one were considering using both the heating and cooling over the course of a 24-hour period. With proper ventilation and building design that takes into account the laws of physics, air conditioning is needed only when it’s so hot that the night time temperatures are not cool enough to get the building down to a comfortable temperature by morning.
I’m more interested in the spring/fall times when you can have a week where air conditioning is justified followed by one in which heating is justified. So switching over on a day’s notice could be useful.