Re: Vertical U-Tube Ground Heat Exchanger and Ground source heat pump model

[kenyym@xxxxxxxxxxxxx]

Quoting Jeff Thornton <thornton@xxxxxxxxxxxx>:

> At 01:34 AM 3/15/2004 +0800, kenyym@xxxxxxxxxxxxx wrote:
> 
> >I am using Type 504 (Ground source heat pump model) and type 557a (Vertical
> >U-tube ground heat exchanger) and I have got some questions regarding 
> >these two
> >components.
> 
> >In type 557a, there is a parameter called initial surface temperature and
> its
> >default value is 20 deg C. I am interested in studying the ground
> temperature
> >variation in the storage volume and I found that this parameter will 
> >affect the
> >temp. in the storage volume. I would like to know what does this parameter 
> >mean
> >and is the default value valid for application in Hong Kong. If it is not
> >valid, how can I find the corresponding value for my application.
> 
> You are correct in that the surface temperature parameter will affect the 
> temperature of the storage volume.  An excellent estimate for this 
> parameter is the average annual air temperature for the location you wish 
> to study.
> 
> >In type 504, the external files contain the heat pump performance data. I 
> >would
> >like to know if those data are standard for geothermal heat pump or I have
> to
> >find the heat pump performance data relative to my own design condition.
> And
> >for my own design conditions, the total cooling capacity is 234 tons of
> >refrigeration, how could I enter this into the component for simulation.
> 
> The catalog data files provided with this model are for a "typical" 
> geothermal heat pump - I believe the size is in the 2 to 3 ton range.  You 
> should find manufacturers catalog data for the heat pump you will be using 
> for the project and create a data file following the format provided in the 
> provided sample files.  I'm doubting that there is an available machine 
> capable of producing 234 tons of cooling so you'll have to use multiple 
> units of Type 504 or you could scale the data in the catalog files up to 
> 250 tons - but this approach can neglect some of the advantages of using 
> heat pumps in commercial applications; namely the thermal benefit of having 
> some heat pumps in heating mode and some heat pumps in cooling mode.
> 
> >Finally, I would be very grateful if you could send me more information
> about
> >this two modules, as well as any other modules or information related to
> >geothermal heat pump system for air conditioning application.
> 
> We have published quite a few articles and technical reports on modeling 
> heat pump systems with TRNSYS.  I can send you the links if you are 
> interested.  There is also a new technical description manual for both Type 
> 504 and Type 557 that will be released with Version 2 of the TESS libraries 
> (Spring 04 with the release of TRNSYS 16).  While the 
> parameters/inputs/outputs will be slightly different from the version you 
> are using, the technical description could provide some helpful 
> information.  E-mail if you'd like an early version of these documents.
> 
> With kindest regards,
> 
> Jeff Thornton
> TESS
> 
>
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> 
Dear Jeff Thornton:
Thanks for your kind reply. I have got some question about entering the catalog
data of the heat pump. In the cooling correction data sample file, there are
multiplies for correction with wet bulb temperature higher than dry bulb
temperature, this is not reasonable and the manufacturer data also doesnot
contain this value. Therefore I don't know how to treat it. Also, I would like
to know how to connect multiple units of type 504 for my application. I can
only find the largest capacity heat pump with 25 tons.
Finally, I would be glad if you could send me the articles, technical reports
and the technical description manual you have mentioned.  
Thanks a lot,
Ken Wong