Forum Replies Created
-
Posts
-
Re: heat pump tumble dryer
Hi, came across this thread by chance looking for heater element info for a second hand hotpoint (what crap) and had to say hello and offer my ha’penneth worth. Hope its ok.
Until recently I’ had spent a ‘few’ years designing building repairing, and generally slaving for different firms involved in commercial and industrial dehumidifiers.
First I must say that heatpump tumble dryers are definitely the way forward commercially but not necessarily for domestic use. Heatpumps generally are VERY efficient when running but do take a while to get going. They use a lot of power to get the process started because you also need a high heat source (not only in terms of temperature but mainly quantity) to get the process going to evaporate the water vapour. This really negates the benefits but commercially the trade off with time saved is worth it. Once that water vapour has condensed giving up its latent heat energy and adding to the refrigeration process then it becomes viable. Down sides are many, and believe me I know. The biggest is the mechanical damage caused. Because there is little absolute control, once the process starts it can tend to cascade. Which is good for the process and time scales but I still have scars on my arms I got from burns off the very high temperature condenser coils and pipes while working on them. Basically because given that the refrigerant temperature equates to pressure of refrigerant you might imagine that some serious pressures are normal. I don’t have a comparator with me but 400psig was common using R22. Compressors did not last.
These problems would be exactly the same albeit on a smaller scale for a domestic dryer. Believe or not there was a time I considered patenting the idea / process (before Philips/ whirlpool) but just didn’t consider it could really work without millions on research and workshops which I’m not ever likely to have.
However the basic principles are unchanged from years of heat pump use way before my time and are still very much in use in many factories today drying sweets and bricks. My favourite (in physics terms) was a system in a factory drying pallets, a warehouse full at a time. It used half a dozen prestcold compressors running R114 with chamber (Drying area) up to 90’C. Humidity 100{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d}. You couldn’t stand in front of an open hatch door because of the heat. The gases (water vapour) was laced with so many corrosive chemicals from the drying wood that only large pipe Aluminium evaporator coils could resist them. Each run took a week and often two or three weeks at a time.
Imagine trying to explain that to the missus.Re: dryer choice?
Thank you for all the replys.
I’ve had a look round on the web at different pics / specs I must say with out seeing it, it sounds great but looking at pictures of it seems it looks more like a large keybox or something. However as long as it does the job.
Only thing that concerns me looking at the various pics, is whether the large door will open over the plinth board. So definatly must see it in the flesh. I’ll check out Currys / Comet again over the weekend. And must say I hadnt noticed anything like this model before there, and have been looking on and off for a few weeks now.Re: dryer choice?
Sounds like its just the job. I’ll look in to it, (avilability, supplier etc. ) thanks
Just to add though its amazing how people are now ‘conditioned’ to accept whats on the front shelf as it were, and expect to pay more for less.
Reminds me of an old saying my mum used to say.“Have what you’re given…and like it”
