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Old 02-13-14, 04:03 AM   #8
jeff5may
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Quote:
Originally Posted by MN Renovator View Post
What sort of refrigerant do these use in order to produce enough heat rise to dry clothes quickly? I keep seeing stuff about it being tough to get temperatures above the 120-140f range efficienctly or even above 140f at all. My electric dryer has a 5kw strip in it so 17000BTU. What are the specs on a heat pump dryer?
The temperature range of a clothes dryer is a good fit for butane or r134a. The high condenser temp is no problem with the right refrigerant. As in automobiles, all you need is heavier piping on the high side.

R410a was specifically designed for the residential HVAC sector. It has a little more heat capacity than R134a, but at its increased operating pressures, it gets above its triple point sooner. Above around 160 degF, it cannot exist as a liquid. More importantly, associated dew pressures above 140 are like 600 psi+.

In comparison, R134a has a critical temp of 214 degF and 590 psi.
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