Posted By joe.ami on 08/25/2009 9:11 PM
... With a hydro unit, hot water is on demand. Hot water tank is indirect fired storage.

Posted By a0128958 on 08/25/2009 9:15 PM

 

Interesting.  HWH tank becomes the buffer tank when installing a Hydro model, and no additional tank to install.

Wish I had a Hydro unit instead of my WaterFurnace.  Would have a correct installation then, with my gas-fired HWH at the moment direct connected to my GSHP unit.

Best regards,

Bill

... reliability has been a problem that new owners (Research Products) hope to fix. To date most Hydro owners would be glad to trade you for your WF.

Posted By jokin on 08/28/2009 10:26 AM
Hello..  I've been reading this forum for a year or so now and never posted until yesterday.  I love the sharing of good ideas and experience that is happening here.  

I have a desuperheater kit on my Tranquility 27, 3 ton unit, but I have not hooked it up until now.  I was excited to see the real world performance data some of you are posting here. 

I've been thinking about this for some time and have some questions..... 

Is there anyone located in a heating dominated climate that can provide similar information on how the units operate in heating mode ?
In heating mode would the desuperheater source (refrigerant temperature) get any hotter ?  [u]It could depending on loop and airflow conditions[/u]

If so can we expect higher delta T across the desuperheater and higher desuper heater leaving temperatures when operating compared to what was shown above for cooling mode units?  (The manf. catalog seems to indicate this... as the heating mode DSH capacity is roughly 3 times the cooling mode capacity for the same conditions (HP EWT, DSH EWT, etc.))  [u]Perhaps, but HP EWT will be much lower in heating season, assuming closed loop and DSH EWT somewhat lower[/u]

My unit runs on first stage maybe 2-5 hours per day in the winter on average.  My thought is this should be more than enough capacity to generate all the hot water we use in a given day... provided I pipe the desuperheater correctly.  [u]That depends on your demand for hot water, temperature you require. Figure 5-10% of unit capacity available for DSH. For example 4 hours run time at 30kbtuh means no more than 12kbtu for hot water. That only heats about 24 gallons of water through a 60 deg F rise. Per DOE figures average house uses 64 gal HW [/u]

If I add a buffer tank(an unpowered electric WH), the current electric water heater we have will still use the same amount of energy to overcome its standby losses, but would just use less energy to recover tank temperature as hot water is used, because the in coming water temperature (from the buffer tank) would be hotter than typical incoming water @ ~ 55 deg.  So with this setup, I can't save any energy unless I use some hot water correct ??  And the more hot water I consume the more savings potential there is (assuming your unit runtime is sufficient to allow the desuperheater to run).  [u]See above calculations[/u]

With a buffer tank setup like this, in cooling mode, days you don't use any hot water, the operation of the DSH would actually increase energy usage (when compared to HW system without DSH), as the compressor would be moving heat from the air to the tank... the tank would loose heat to the air again, and compressor would move heat from air to the tank via the desuperheater and the compressor energy required to move the heat around would be wasted correct?? [u]Minimal if tanks and lines are well insulated, extra run time might help with dehu[/u] 

I'm wondering the best way to pipe the desuperheater and HW tank(s), in my heating dominated application (we ran the AC about 7 days this summer), normal average use might be 12-14 days. [u]Look for Bergy's diagram[/u]

Is there is a way to pipe the system in a way to allow (2) things...

1st in Heating mode...  generate hot water to cover tank standby loses... by maintaining the both tanks at usable 120 deg F or so (as unit runtime allows)

2nd (assuming above assumption about cooling operation) allow same thing as above except final tank only (to minimize summer HW standby losses) [u]Again, follow Bergy's diagram - you don't want main tank water passing through the DSH, just buffer tank water[/u]

This turned out lots longer than intended, sorry for the overload.  Any comments would be appreciated.

 
[/quote]My comments are underlined above