Distribution Units Effect on System Efficiency

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I'm working with a situation where a few dozen single family homes (~2000 sqft) are connected to a district heating loop supplied with steam from a boiler. Currently, the homes are equipped with copper fin-tube baseboard heaters. A question has been posed if we switch to cast iron radiators in the homes, can we reduce the energy consumption of the system? I understand that the fin-tube heaters transfer a greater proportion of their heat via convection rather than radiation, and so the mean radiant temperature will be greater when the cast iron radiators are operating, because they radiate a greater portion of their heat. This leads to a higher mean radiant temperature and more comfortable conditions. The 2004 ASHRAE Handbook puts it this way:

"RATINGS OF HEAT-DISTRIBUTING UNITS
For convectors, baseboard units, and finned-tube units, an allowance for heating effect may be added to the test capacity (the heat extracted from the steam or water under standard test conditions). This heating effect reflects the ability of the unit to direct its heat output to the occupied zone of a room. The application of a heating
effect factor implies that some units use less steam or hot water than others to produce an equal comfort effect in a room."

Of course, this will only translate to a real-world reduction in energy savings if the occupant reduces the thermostat set-point, because the t-stat takes a drybulb reading, not a mean radiant temperature reading.

Other than the assumption that the t-stat would be set lower by the more comfortable occupant (probably unlikely in most scenarios - they'd just keep it at the number they're used to - e.g. 68-70, does anyone have any non-anecdotal evidence that would support energy efficiency improvements that could be expected for installing cast-iron radiators over baseboard copper fin-tube heaters? Again, the application is district steam heating.

Thanks much for the insight!

Steamhead (in transit)

Do these systems

use steam-to-water heat exchangers to heat water that feeds the baseboards?

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