Re: [EnergyPlus_Support] Re: Ground temperature of Singapore

If you don't enter the indoor temperature, you will likely have
unrealistic results.

You have not given your problem to the helpdesk == this is a user=user
forum.

Rule of thumb - make your ground temperature -2C from your indoor
temperature. I believe this is stated in the aux programs document if
you choose not to believe the calculations from the slab program.

On 2013-01-18 19:32, academicryan wrote:
> Hi Linda I have read that section at least 4 time trying to
> understand it. I still don't really understand it very well but I'm
> pretty sure its simply telling me to use the Slab program in the
> EnergyPlus Utilities.
>
> I've mentioned that the Slab program gives unrealistic results. What
> I particularly don't understand about the Slab is why there is an
> input for monthly averaged indoor temperature. This means I need the
> indoor temperature to calculate the ground temperature. But to
> simulate the indoor temperature, I need the ground temperature. This
> seems like an impossible chicken/egg scenario of which one comes
> first. I've even read somewhere I'm supposed to start with an
> arbitrary indoor temperature and keep doing this chicken/egg cycle
> until both ground and indoor temperatures converge and stabilise.
> This
> seems really silly and tedious but maybe that really is what I'm
> supposed to do?
>
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Linda Lawrie wrote:
>>
>> Read the auxiliary programs document on Ground heat transfer with
>> EnergyPlus. Look at the EPW file ground temperatures as well (which
>> are
>> not suggested for the Site:groundTemperatures values)
>>
>> On 2013-01-18 18:49, academicryan wrote:
>> > Update: *EnergyPlus developer please respond*
>> >
>> > OK I now know how to calculate soil temperature as a function of
>> > depth from Hillel, 1982.
>> >
>> > Essentially his equation says that at 0 m depth, monthly average
>> soil
>> > temperature is the monthly average air temperature plus 1Ã?Â°C. This
>> is
>> > basically a sine wave. With increasing depth, the soil temperature
>> > gets closer to the annual mean air temperature plus 1Ã?Â°C.
>> >
>> > NEW QUESTION: Is this what
>> 'Site:GroundTemperature:BuildingSurface'
>> > wants? i.e. 0 m depth soil temperature. Or some other depth? Or
>> some
>> > other 'ground temperature' altogether?
>> >
>> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "academicryan" wrote:
>> >>
>> >> Can somebody please help me do a very simple task.
>> >>
>> >> Calculate/find the monthly ground temperature for Singapore. To
>> >> clarify, this is the input for the
>> >> 'Site:GroundTemperature:BuildingSurface'.
>> >>
>> >> ------
>> >>
>> >> Extra info - I've already tried the Slab utility, it comes up
>> with
>> >> very unbelievable results. Calculating some months below 17Ã?Â°C
>> when
>> >> Singapore air temperatures never drops below 21Ã?Â°C.
>> >>
>> >
>> >
>> >
>> > ------------------------------------
>> >
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>> > energyplus-support@...
>> >
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>> >
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>> >
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>> >
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>> under
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>> >
>> >
>> >
>>
>
>
>
>
> ------------------------------------
>
> Primary EnergyPlus support is found at:
> http://energyplus.helpserve.com or send a message to
> energyplus-support@xxxxxxxx
>
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
>
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
>
> Attachments are currently allowed but be mindful that not everyone
> has a high speed connection. Limit attachments to small files.
>
> EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under
> the Documentation link and press the "search" button.
> Yahoo! Groups Links
>
>
>