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

[kenyym@xxxxxxxxxxxxx]

Dear Trnsys users:
I am an undergraduate student at the University of Hong Kong. Now I am studying
the Geothermal heat pump system for air conditioning applications under Hong
Kong climatic conditions. 
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. 
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. 
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.
Regards, 
Ken Wong