re: advice needed for cooling residential hydronic system...
3 jul 2001
>> >if the room air is not stirred pretty hard the hotter it is outside
>> >the more likely that the downward flow will be limited to relativly
>> >cool air settling...
>> let's cut out the bullshit. try some basic equations and numbers...
>sorry. bullshit won't help produce convection where none exists. the
>difference between striation and convection in a real situation depends on
>details of how much stiring force is generated...
i think the word you are groping for is "stratification."
>there is nothing to calculate bud...
if you don't believe the exterior walls will cause convection currents,
consider radiation. al mentioned an r50 ceiling. at about 70 f, with
emissivities close to 1, the radiation conductance between ceiling and
floor is 4x0.1714x10^-8(460+70)^3 = 1 btu/h-f-ft^2. here's a thermal
equivalent circuit that even you might understand:
70 f ---www------www--- 100 f
>the convection force of the rising very hot wall air can suck some of
>this cold air into it, but the mixing will be weak and will reduce as
>the overall room striates and heats.
real physicists use numbers, fred.
>> >the swamp cooler idea is ok...
swamp coolers work all day, and move warm outdoor air into a house.
i described an indirect system with storage that only loses heat
at night and doesn't move any outdoor air into a house.
>...a swamp cooler is a common term for a general class of evaporative
>coolers that require forced circulation , dry outside air, and a lot
>of water. your modification does not remove it from the general class
>of evaporative coolers that i would describe as a swamp cooler...
indiscriminately... would you say a chair is a lot like a beach ball
because it looks the same if you wrap it with enough cotton wool? :-)
>> >steam and stirling motors are heat powered rather than direct combustion
>> >powered. i would run a steam motor to drive a heat pump for cooling.
>> which stirling engines? if nobody makes these mystical gadgets, how would
>> you make them in your garage with standard materials, with no little boxes
>> that say "a miracle happens here"? and what would their efficiency be?
>lots of people make stirlings? what part of the world do you live in that a
>back yard garage can't make a decent motor? the stirling is easy enough to
>make. it is just rather expensive to buy, since it is not being run off in
>the millions per year...
and what would "its" efficiency be, with a tiny temperature difference and
real heat loss and friction? the alternative energy world is littered with
inefficient and uneconomical one-of-a-kind experiments.