daveklepper One real growth area in both loose-car and unit-train railroading is chemical products, both raw-material input and product output and export. This is primarily focused on the Gulf Coast, Texas in particulary, with UP the prime beneficiary, followed by BNSF, and KCS a distant third.
One real growth area in both loose-car and unit-train railroading is chemical products, both raw-material input and product output and export. This is primarily focused on the Gulf Coast, Texas in particulary, with UP the prime beneficiary, followed by BNSF, and KCS a distant third.
Thanks to Chris / CopCarSS for my avatar.
Paul MilenkovicHow does a cold weather heat pump outside unit work when you get snow drifts? Do you have to venture outside and shovel off the snow?
Yes, because you still need the airflow for the heat content. These things work with refrigerant that boils in a different range, and probably have somewhat higher fan circulation as the heat content for a given mass flow through the 'evaporator' is less.
Overmod Paul Milenkovic How does a cold weather heat pump outside unit work when you get snow drifts? Do you have to venture outside and shovel off the snow? Yes, because you still need the airflow for the heat content. These things work with refrigerant that boils in a different range, and probably have somewhat higher fan circulation as the heat content for a given mass flow through the 'evaporator' is less.
Paul Milenkovic How does a cold weather heat pump outside unit work when you get snow drifts? Do you have to venture outside and shovel off the snow?
Back in the eighties, I was in an apartment in New Jersey in the winter that had a heat pump with resistance back-up. I noticed that when there was snow on the ground, you would periodically see "steam" (actually condensation) rising from the outside unit. I don't know, but I'm guessing that it periodically reversed the pump to melt the snow. Whether it used the resistance heater to heat the inside unit at the same time, I don't know. I keep wanting to use the terms "condenser" and "evaporator", but their roles keep reversing. Anyway, this is mostly conjecture, so if anyone knows otherwise....
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"A stranger's just a friend you ain't met yet." --- Dave Gardner
Growth. Plastic use will increase, fertilizer, medical chemistry, etc.
When the reversing valves in the heat-pump system are set to 'heat', the outside coil acts as the 'evaporator' (to draw whatever heat from the outside it can). Just as in normal 'air conditioner' operation, if the refrigerant cools the evaporator below the freezing point of atmospheric water, ice will form on the coil and may eventually proceed to disturb airflow of even plug it... at which point the refrigerant will no longer boil to absorb heat and start slugging liquid into the compressor, which is Not A Good Thing. I would not be surprised to see arrangements to use resistance heat externally to keep the coil free of condensation -- of course the COP does not help the efficiency of resistance heat vs. using it directly after the air handler as in conventional resistance HVAC, but a relatively smaller amount of power can be used for 'de-icing' than for full space heating.
Now, in the evil old days, when the only provision of resistance heating in these systems was as 'emergency heat' when things got too cold for efficient heat-pumping, the de-icing would probably be done by periodic reversal of the reversing valves and operation of the outside coil as a condenser ... raising its temperature from 'inside heat' now generated silently but relatively inefficiently from the resistance -element array. This of course cycled the reversing arrangement more often which would increase likelihood of something sticking or failing... but would be cheaper to build.
If you split the refrigerant systems, as becomes easy with ground-source heat pumps, you have one sealed loop for cooling, and a separate one with different refrigerant and component sizes only for heating. These can use refrigerator-size compressors with appropriately higher reliability and the refrigerant loops are sealed so no wacky valves to fail or leak. I could spend quite some time explaining the ways this can be preferable, but it has little to do with railroad applications.
themanAs we wave the 2010s goodbye, it is becoming increasingly clear that we may have to wave the railroads goodbye as well. The future looks dark, very dark.
Rio Grande Valley, CFI,CFII
This is the decade in which I will retire in (2026), I am comfortable that I will be able to.
My neighbor bought his house with the geothermal heating system already in it. He eventually shut it down in favor of a propane furnace, because the well maintenance/repair costs were eating his lunch.
MidlandMike My neighbor bought his house with the geothermal heating system already in it. He eventually shut it down in favor of a propane furnace, because the well maintenance/repair costs were eating his lunch.
You'd be surprised at all the little 'gotchas' over the years that have had to be learned regarding the design, care and feeding of various kinds of ground loops. One somewhat amusing variant with its own list of cautionary tales is the technology that puts the Freon exchanger in the ground-source region rather than a secondary antifreeze loop ...
It does have to be said that the Slinky loop in semi automated trenching has a number of attractive advantages over deep vertical wells with Bentonite especially in uncertain soils. I did not see that approach coming so cannot plead superior acumen in design innovation. It does help however to think carefully about the various things that might be expected to fail over the presumptive 'financed lifetime' of one of these systems, and ways to design all the little details for quick and 'as easy as possible' remediation.
It came as a surprise to me that many of these systems lacked freeze protection for the portions of the ground loop out of the constant-temperature zone, or had inadequate access to the circulation pump or its connections. This shouldn't be rocket science. (Although there can be considerable technical sophistication a la optical-fiber field-splicing kits for making flow-optimized high-integrity field joints in the ground-source loop tubing...)
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