Designing heat pump dehumidifiers
Dr Eric Scharpf, an energy management expert, has experience in the design and construction of heat pump dehumidifiers for industrial use in timber drying. In this video, he explains how, working with Professor Gerry Carrington, a radical design was developed and taken through to a marketable product.
Transcript
ERIC SCHARPF We had a lot of fun with Delta S. It’s a company that a friend of mine, Gerry Carrington, and I created to take ideas about how to move energy around with heat pumps and how to use that more intelligently to dry things out, cool things off, do all sorts of things, mainly with drying stuff. And we created it based on some ideas that we had to apply heat pump dehumidifiers to drying timber in various operations a heck of a lot more efficiently and more evenly and with a better product than you could by other methods.
We developed and patented a number of aspects of special heat pump design variations to make it work very, very well with timber drying. We arranged some of the main heat exchange items – things that give off heat or suck up heat – in very unusual configurations in the circulating air flow in the timber dryer. And we operated it with controls and at temperatures and based on sensors of different conditions in a very different way than anyone else had before.
We broke a lot of informal rules in the heat pump design in order to make the heat pump system just as efficient whether the air was flowing this way or if the air was flowing that way in it. But also we had some really neat control system elements that allowed the heat pump to only work as hard as it absolutely needed to to match the way the timber dried during the time it sat in the timber-drying kiln.
We look at each customer and figure out how much wood are you processing, what kind of size stack do you want to work with, how long it’s going to take and how much more wood you’re bringing in, how much water the wood has inside it when you’re cutting it and putting it in there, so we know how much moisture needs to be removed.
And then we run that through some calculations and match that against specific pieces of equipment you can buy on the open market and then basically bolt everything together, ship it on up, wire it up, plumb it in, make it work, show that it works.
And there you are – that company can dry timber for years at lower cost, more evenly and therefore have a better dried timber product than they would otherwise have and faster than other heat pump systems would be able to do.
Acknowledgements: Dr Eric Scharpf, University of Otago, Department of Physics
Otago Daily Times Delta S Technologies Paul McMaster, Otago Lumber Yard
