View Full Version : Hot Water Heater? De-Superheaters?

05-04-2007, 03:23 AM
I am new to the forum and excited about being here. Has anyone had any experience with de-superheaters that supply hot water using a residential heatpump?:D

05-04-2007, 07:26 PM
Hi and welcome to the forum.

05-04-2007, 07:54 PM
Yes, I do.

05-04-2007, 10:58 PM
Welcome, I've only been a member for about a month but have learned that the only stupid question is the one not asked.
What type of heat pump is it? Water to Water? Or just reclaiming heat for domestic use.

06-04-2007, 12:14 PM
I am new to the forum and excited about being here. Has anyone had any experience with de-superheaters that supply hot water using a residential heatpump?:D

Hi ya.
Iv'e worked with heatpumps and they will deliver hot water above 60 degC and then it will supply hot water at 40degC to heat the underfloor heating.

Hot water needs to be above 60degC on a regular basis to eliminate any legonella bacteria that may be pressent.

Cheers taz.

06-04-2007, 02:13 PM
Photo of a desuperheater on a small water cooled water chiller

06-04-2007, 06:27 PM
And here's one on a pack we made http://www.refrigeration-engineer.com/forums/showthread.php?t=3566

09-04-2007, 11:07 AM
Does anyone know where to find data so that I can build my own heatpump hot water heater....:rolleyes:

11-04-2007, 09:00 PM
your regular wholesaler

12-04-2007, 05:24 AM
It is an air to water heatpump, I am not sure why they are called heatpump. That leads us to think it has a reversing valve. It is basically an air condiitioner that takes the hotgass from the compressor and runs it through a heat-exchanger that removes the heat. It then has a evaporator coil that air is blown through and has to be either ducted into the house during warm months and exhausted during cold months. The air in warm months is cool de-humidified air and can be a supplement to your home unit. :cool:

12-04-2007, 09:06 AM
That is a rooftop heat pump. Not an air to water heat pump.

15-04-2007, 06:00 AM
Hi wstokes
Making a heatpump hot water system is easy enough just by using a cheap reverse cycle outdoor unit from a R22 split system airconditioner, capacity of around 3 kW and putting an appropriate sized heat exchanger coil immersed in the water storage tank as a heat exchanger, just measure the indoor unit fan coil tube for a basic coil capacity. Put the indoor unit fan coil on the nature strip, someone will take it off your hands! Use a klixon on the tank surface to cycle the compressor in heat mode and away you go, should take about 4 hours to heat about 300 litres of tank water from 12 degC to 60 degC with an outdoor ambient of about 20 degC. The problem you may find that when heating water to 60 degC is that when the water temperature gets higher than 40 degC the hot water storage tank begins to lose its condensing capacity and becomes just a sub cooler, therefore the the C.O.P is very low around this temp because the systems evaporator will not be getting a condensed liquid. The head pressure/ temperature will be very high and the suction pressure/ temp will not be low enough to ensure adequate compressor cooling but there are ways around that. Have fun with it.

16-04-2007, 04:45 AM
Thanks for the info sometimes too much time on your hands is a bad thing........Woody

16-04-2007, 05:02 PM
To add to what wstokes wrote...

Are you looking to capture some of the heat exracted by your condenser? I.e. Perhaps you could add an in-line water cooled condenser to your existing system? There are companies that do this for swimming pool heaters, and others that reclaim heat from geothermal heat pumps, regardless of what direction they're running in for the given season.

Obviously, if you are using a residential "heat pump" system, as one would be called incorporating a reversing valve, you'd need to rig up something different so you don't rob your warm air during the winter ;-)

17-04-2007, 02:45 AM
I am gonna to install a desuperheater to heat water when my heatpump is running. This will consisit of an heatexchanger and small circulator pump. I am also thinking of trying a small water cooled refrigeration skid, I happen to have one that is a Copeland about 3/4hp 230v. I also have a air cooled condenser that was taken off another skid, it will serve as my evaporator. I am gonna try a TXV for my meter device..........Any comments.....:rolleyes: