On 12/28/2015 2:13 PM, dpb wrote:

Which paragraph discusses impact of solar radiation on heat gain in a
residence? Or, "comfort factor" compensation for air infiltration?

Where does it tell me the economic tradeoff of using evaporative cooling
on a particular day vs. refrigeration? Or, the penalty of using
refrigeration *after* evaporative cooling?

Where does it tell me about the (affordable) COTS control system that I
can PURCHASE to do these things?

Well, that's a completely different kettle o' fish than citrus grove freeze
protection which is all I had addressed...

Knowing what to do and having something that will actually *do* it
are entirely different things! You can wire an on/off switch to your
furnace and keep the interior of your home at a comfortable temperature...
by flipping it on and off throughout the course of the day!

Not many people would opt for that form of control, though! So,
someone makes an AFFORDABLE device that does this FOR you and
suddenly it's commonplace!

I'd *really* not like to have to "reinvent the wheel" so would greatly
appreciate those pointers! :

So, please tell me -- and the rest of those reading -- exactly *who* has
"thought of it" before?!

I guess *your* problem is failing to understand that not all problems
*have* been "thought of before". Or, having too narrow a concept of
what you can actually *do* with "data" once you have it! It's a
relatively common problem: people who can't see past their own
experience...

I spent some 40 yr of engineering consulting doing data collection and usage so
I've a pretty good idea of what can be done w/ data...from online coal ash and
elemental analyzers to pulverized coal flow w/ acoustic noise inference via
nonlinear processing of the chaotic (as opposed to stationary stochastic) flow
patterns to more conventional vibration and such including online heat-rate
performance monitoring for fossil plants (much more related to your HVAC
question albeit on a much larger scale and with temperatures and pressures a
little higher!

And *no one* commercially addresses all of the areas that I've mentioned
with an integrated, affordable controller. Because the "citrus growers"
don't give a rat's ass about interior HVAC controls; and the HVAC control
developers don't give a rats ass about citrus protection, cactus protection,
orchid protection, etc. The folks who designed the controller for our
evaporative cooler cared nothing about the controls for the furnace
(i.e., added their own indoor temperature sensor despite the fact that
the air conditioner *and* furnace already have this!).

No one deals with anything outside their own little microcosm of
experience.

So, you'd end up with N different systems (assuming you could find
COTS systems to do these things!)

In the specific areas you've mentioned here I don't know offhand who's done
what; granted, but that wasn't what I thought you were interested in as noted
above.

I notice you didn't mention anything about HVAC despite my reference to it
early in the thread:
I'm not interested in personal comfort as much
as having "real data" for the HVAC system and
to know whether the citrus trees are in jeopardy.

While it's a reasonable conjecture, I'd venture 90% of homeowners will get far
more "bang for the buck" simply by adding insulation or the other routine
energy-efficiency changes than what could gain by dynamic control such as you
posit above.

Actually, you get a lot of benefit (energy saving and comfort) by
putting smarts into a home thermostat. SWMBO opts for an open window
despite the fact that the outdoor temperature is 30-ish at night.
Neither of us wants the house warm while sleeping. OTOH, if I'm up
late working, I don't want it *cold*. Both of us want it warm
*before* we wake up -- yet having it warm too soon before rising
would be wasteful of energy.

Adding insulation to a building after it's been built isn't always possible.
E.g., our walls are cement block. Adding insulation would require
adding a layer of styrofoam outside the block and reapplying the stucco
to that surface. Or, framing *in* the interior walls to create additional
space for fiberglass bats or blown in.

Adding ceiling in the ceiling is essentially impossible as the roof
is 9" above the ceiling -- and can't be "filled solid" or it won't
be able to breathe. So, unless I wanted to incur serious expenses
to remodel the house, *smart* control of the HVAC is a far easier
way to save money. *And*, can be applied to my neighbor's house
(and HIS neighbor's house, etc.) just as easily/econmically as here!

I.e., the solution SCALES well!

Likewise, a solution to addressing the citrus problems we encounter
in our little microclimate would benefit everyone in the neighborhood
with citrus trees or other "frost tender" plants. E.g., the Saguaros
also don't like the cold; and, with a 75 year investment in a plant
(if it has "arms", it's 75 years old or more), you don't want to
lose it just because of a weather event.

Similar to the questions who can do serious control of freeze mitigation in
their backyard, how many houses have both evaporative _and_ refrigerating
cooling systems?

Here? Probably 30%. There has been some talk of banning evapporative
coolers as water is precious but the cost of refrigeration makes that
as the EXCLUSIVE form of cooling impractical for folks with limited means.

(recall my comment seeing past their own experience?)

I'd still guess there's quite a bit of useful work having been done and for
your purposes worrying about a degree or two of error in that external
temperature is also a case of misplaced concern since as you mention it isn't
that critical to a precise degree what an internal temperature is if it's
somewhere in the mid-range of the comfort zone most folks will be happy enough...

https://www.ashrae.org/resources--publications/bookstore/thermal-comfort-tool?utm_source=promotion&utm_medium=landingpage&u tm_campaign=86179&utm_term=86179&utm_content=86179

It's not just "perception". Take the leftmost two digits of your income and
figure out your effective hourly wage. How happy would you be if your
employer compensated you based on that? On average, you'd be cheated out
of $500 for every 2000 hours (1 year) worked.

Hence precision is more important than accuracy.

OTOH, precision without accuracy doesn't help for things that have
actual physical limits: plants die at fixed temperatures regardless
of how *precise* the temperature measurement.

A precise but inaccurate temperature measurement will be reflected in
additional inaccuracy for any other measurements/calculations on which
it is relied.

As for the predictions you're talking about, application of the load
calculations manual would basically provide all the information required to
evaluate alternatives as far as input costs, etc., if applied to a specific
structure and installed systems as opposed to the sizing calculation itself.
But, all the basic heat loss/input computations are outlined to do it...

I'm sure there are optimizing controls already for commercial buildings altho
not my area of direct expertise but again I doubt it'll be found to be
cost-beneficial to this degree for single-family residential applications.

Exactly. The *controls* are too expensive. But, the algorithms and
instrumentation are not.

A simple test to see if it's rained recently makes a big difference
in the amount of water used by an otherwise dumb/naive irrigation
system! (why water if it rained yesterday? Or, if it is RAINING
TODAY??)

An irrigation controller that considers evaporative and transpirational
losses wouldn't foolishly water during the hot part of the day as
~40% of the water is lost!

These sorts of things are reasonably well known -- yet frequently
ignored by the folks charged with setting the "dumb" controllers.

Beyond the thermostat runback at night and converting old, low-efficiency
furnaces/boilers to higher-efficiency units and the aforementioned closing up
of other heat/cooling loss venues, the remainder is, in my estimation, likely
to be found to be in the noise level of actual cost/benefit.

What do you do when the house is empty but it's daytime? Keep it nice and
warm -- in case someone comes home from work, early? Do you connect the
HVAC to your telephone/internet and REQUIRE the homeowner to "phone home"
prior to arriving and "turn up the heat" so its warm (cool) when they
walk in the door? Should *they* look at the current weather conditions
and make the decision as to WHEN they should tweek the temperature
setpoint? Perhaps query the house to see what the actual indoor
temperature is, the outdoor temperature, wind speed, etc. and make
a "gut feel" calculation? Or, maybe just wait until they get home
and manually make the change at that time? Perhaps opting not to
let the house deviate too far from that desired temperature because they
don't want to have to wait a long time for it to return to their
"comfort zone"?

What if they have forced air vs. hot water heat at their new residence?
Should they relearn these "gut feel" calculations to reflect the
different control actions of their new HVAC plant? How soon before
retiring/arising should they adjust the AC/furnace/heatpump in the bedroom
area as opposed to the living areas? (multizone control)

Don't look at *your* experience(s) and extrapolate from that unless you're
aware of what other folks' experiences are!