[Bldg-sim] [BLDG-SIM] earth-air exchanger (earth channels)
Neeraj Kapoor
near_ej at yahoo.com
Mon Jun 23 03:48:15 PDT 2008
Thanks Brian,
Looking up on the internet I came across a link that summarizes one Dr.
Didier Thevenard's (of Numerical Logics Inc.) search carried out online
and compiled together regarding this subject --
http://www.emr.gov.yk.ca/energy/pdf/biblio_search_earth_tubes_v3_1.pdf
-- It might be useful for folks who may want to propose / model
earth-air tunnel heat exchange (EATHE) systems.
I am taking the liberty of posting the relevant part of your reply
(below) as well, for the benefit of everyone on this list.
sincerely,
Neeraj
Brian Fountain wrote:
> I too am just starting a project proposing the use of Earth Tubes.
> Currently I am modeling in eQUEST as well and have not found a good
> way to model this system.
>
> I did run across the following article:
> http://gundog.lbl.gov/dirpubs/SB06/kwangho.pdf
> which describes an earth tube algorithm implemented in EnergyPlus.
It
> also describes parametric runs for 4 parameters (depth, diameter,
> velocity and length). As yet, I have not tried this as I . . .
> /[omitted text]./
>
> Good luck!
>
> Brian
>
> Neeraj Kapoor wrote:
>> Hello everyone,
>>
>> I am trying to model Earth-Air tunnels in eQUEST located in a
>> tropical,composite climate (New Delhi). Following the last two
>> threads on this issue dated Nov. 2003 and Oct, 2006 (shown below)
>> nothing else seems to have been discussed, especially relating to
>> modeling this strategy in eQUEST? If anyone has had any experience
>> with it then please share. I'd appreciate your feedback. Meanwhile,
>> let me try and explain the system that I am trying to model and how
I
>> am approaching it --
>>
>> Earth-air (horizontal) tunnels utilize 100% outside air as it is
>> blown through them. This brings down the temperature as the air is
>> sensibly pre-cooled for the air handling unit. In the hot-dry months
>> the air is either delivered or is subjected to direct-indirect
>> evap-cooling. For warm-humid periods a small portion of the
>> pre-cooled air stream is subjected to DX coil where it drops most of
>> its moisture and is mixed with the rest of the air stream In
>> principle my strategy will be to model ground-source heat exchanger
>> (GSHX) wherein a fluid (water) rejects or gains heat and transfers
>> the benefit to the air handling unit using 100% OA. I am guessing
>> that the transfer of heat between water-earth via the GSHX and then
>> water-air in the AHU has to be very efficient to diminish losses
>> incurred and model this system fairly accurately. I will finally
>> subtract the pumping energy from the total. Here is the crux, and
the
>> questions --
>>
>> 1. Am I thinking in the right direction?
>> 2. How does one increase the efficiency of the GSHX process to
best
>> reflect earth-air heat exchange? The aim as I said earlier is
to
>> diminish the losses incurred due to the water-earth and
>> water-air processes of the GSHX?
>>
>> For now, I am tied to eQUEST to solve this problem because a large
>> time-consuming part of the model is already accomplished. However if
>> there is a better way to address this with any other tool then
please
>> do not shy from sharing your knowledge. Many thanks for helping in
>> the past and in advance on this one.
>>
>> sincerely,
>> Neeraj
>>
>> Neeraj Kapoor
>> t: +91-99581.70018
>> Kalpakrit Sustainable Environments Pvt. Ltd.
>> New Delhi
>>
>> ---------------
>> Victor Hanby wrote:
>>
>>> >
>>> > On 31 Oct 2006, at 10:07, Yatin Choudhary wrote:
>>> >
>>>
>>>> >>
>>>> >> hi every one
>>>> >> i am trying to simulate a type 56 with earth air tunnel
hypocast
>>>>
>> ,...
>>>> >> want
>>>> >> to compare with a 1.5 TR window unit ac
>>>> >> please advise
>>>> >>
>>>> >>
>>>> >> ======================================================
>>>> >> You received this e-mail because you are subscribed
>>>> >> to the BLDG-SIM at GARD.COM mailing list. To unsubscribe
>>>> >> from this mailing list send a blank message to
>>>> >> BLDG-SIM-UNSUBSCRIBE at GARD.COM
>>>> >>
>>>>
>>> >
>>> > Dr Farraj Al-Ajmi pretty much did this for his PhD studies at >
>>> Loughborough University (UK). It's described in
>>> >
>>> > Al-Ajmi, F., D.L.Loveday and V.I.Hanby 2006 ``The cooling
potential
>>>
>> of
>>> > earth-air heat exchangers for domestic buildings in a desert
>>>
>> climate''
>>> > Building and Environment 41:235--244.
>>> >
>>> > and
>>> >
>>> > Hanby, V.I., F.Al-Ajmi and D.L.Loveday 2004 ``The optimal design
for
>>>
>> a
>>> > ground cooling tube in a hot, arid climate'' Building Services >
>>> Engineering Research and Technology 26(1):1--10.
>>> >
>>> > Farraj wrote TYPES for the ground cooling tube and the subsoil >
>>> environment. I've lost touch with him but I think he has posted
here
>>> > in the past. He might be able to help you with some code. I
>>> modeled > the ac unit sing a fixed temperature approach for each
>>> coil > (evaporator and condenser) then assumed a fixed fraction of
>>> Carnot to
>>>
>>
>>
>>> > get the energy consumption.
>>> >
>>> > Vic Hanby
>>> >
>>> > -----------------------------------------------
>>> > Professor V I Hanby
>>> > Institute of Energy and Sustainable Development
>>> > De Montfort University
>>> > The Gateway
>>> > Leicester LE1 9BH
>>> > UK
>>> > ------------------------------------------------
>>> >
>>> >
>>> > ======================================================
>>> > You received this e-mail because you are subscribed to the >
>>> BLDG-SIM at GARD.COM mailing list. To unsubscribe from this mailing
>>>
>> list
>>> > send a blank message to BLDG-SIM-UNSUBSCRIBE at GARD.COM
>>>
>>
>> * /To/: <BLDG-SIM at xxxxxxxx <mailto:BLDG-SIM at DOMAIN.HIDDEN>>
>> * /Subject/: [BLDG-SIM] earth-air exchanger (earth channels)
>> * /From/: Denis Bourgeois <denis.bourgeois at xxxxxxxxxxxxx
>> <mailto:denis.bourgeois at DOMAIN.HIDDEN>>
>> * /Date/: Fri, 21 Nov 2003 15:27:36 -0500
>> * /List-unsubscribe/: <mailto:BLDG-SIM-Unsubscribe at gard.com>
>> * /References/:
>> <MDAEMON-F200311201548.AA4849171pd80000629044 at xxxxxxxx
>>
>> <mailto:MDAEMON-F200311201548.AA4849171pd80000629044 at DOMAIN.HIDDEN>>
>> <MDAEMON-F200311211204.AA0424687pd80000630311 at xxxxxxxx
>>
>> <mailto:MDAEMON-F200311211204.AA0424687pd80000630311 at DOMAIN.HIDDEN>>
>> * /Reply-to/: denis.bourgeois at xxxxxxxxxxxxx
>> <mailto:denis.bourgeois at DOMAIN.HIDDEN>
>> * /Sender/: postman at xxxxxxxx <mailto:postman at DOMAIN.HIDDEN>
>>
>>
------------------------------------------------------------------------
>> Bonjour Hugues,
>>
>> I'm unaware of any single program that automatically sets this up. A
>> very discrete finite-... 3D conduction model would be desirable, but
>> depending on your specific needs, ESP-r would be a very good
>> candidate as an annual assessment tool. I've used ESP-r for
>> underground air culvert assessment in the past and a couple of
>> graduate students have used ESP-r for similar studies (Y. Jeong, a
>> grad student at Concordia, and another student in Norway (a PhD
>> student I believe) have both used ESP-r for assessing the Media
>> School in Norway, which has an
>> underground air culvert).
>>
>> In Jeong's case, the culvert is modeled as one zone, but it is
fairly
>> straightfoward in ESP-r to subdivide this in, let's say, 10 zones
>> (e.g., a 40m culvert could be made up of ten 4m segments) - that's
>> what I do. This will give you a more detailed assessment, e.g., of
>> culvert surface
>>
>> temperatures along the airflow path (useful for condensation
assessment
>>
>> or to see just how effective the first segments of the culvert are
in
>> relation to the last ones). ESP-r also allows you to set up an
>> airflow network, but 'scheduled' airflows might be OK for your
needs.
>>
>> The main challenge is setting up the surface boundary conditions.
>> Without setting up a 3D conduction model in ESP-r (available, but
not
>> for the faint-hearted), you'll have to specify boundary conditions
>> for each surface. If the culvert is deep enough,
>> you can just feed it monthly ground profiles for ~¾ of the surfaces,
>> with harmonics calculated with standard models (see Maitos and
>> Argiriou) - the same models used for ground-coupled heat pump
>> simulation. If it's deep enough, the daily variations will be minor
>> (~ ±1°C during the course of a month). The remaining ~¼ of the
>> surfaces will more likely feel the effect of the nearby ground
>> surface, so ambient air might be more suitable as a surface boundary
>> condition. If the culvert is very close to the ground surface, then
>> it's a bit more tricky - maybe ~½ of the surfaces need ambient air
as
>> a boundary condition. You can of
>> course 'tweak' the model to see just how sensible it is to variable
>> changes.
>>
>> Another point is setting up the right surface element
'constructions'
>> so on one hand it remains numerically stable, and on the other the
>> constructions remain 'thick' enough so that using monthly profiles
>> remains valid (at least conceptually).
>>
>> Transsolar have modeled culverts for other energy consultants in the
>> past - maybe they've set up some basic modeling approach in TRNSYS
(?).
>>
>> Simpler empirical approaches are available: Argiriou and Maitos give
an
>>
>> overview of existing models found in the literature.
>>
>> Good luck,
>>
>> ----
>>
>> Some references:
>>
>> Jeong, Y., and Haghighat, F. (2002) "Modeling of a hybrid ventilated
>> building, Grong School" /Proceedings of the 4th International Forum
>> on Hybrid Ventilation: An Integrated Solution for Ventilation,
Health
>> and Energy/, Montreal pp.198-207.
>>
>> Maitos, A. (1999) "Cooling with underground air ducts" MSc Thesis.
>> University of Strathclyde: Glasgow. 68p.
>>
>> Argiriou, A.A. (1996) "Ground cooling" in /Passive Cooling of
>> Buildings/. M.J. Santamouris and D.N. Asimakopoulos, eds., James &
>> James: London. pp.360-403.
>>
>> Kumar, R., Ramesh, S., and Kaushik, S.C. (2003) "Performance
evaluation
>>
>> and energy conservation potential of earth-air-tunnel system coupled
>> with non-air-conditioned building" /Building and Environment/ 38
>> pp.807-813.
>>
>> Lay, R.M. (2003) "Earth Rangers Wildlife Centre - case study of
>> concrete use for energy efficiency" /Proceedings of the 8th
>> Environmental and Sustainable Engineering Specialty Conference of
the
>> Canadian Society
>> for Civil Engineering/, Moncton.
>>
>> Sawhney, R.L., Buddhi, D., and Thanu, N.M. (1999) "An experimental
>> study of summer performance of a recirculation type underground
>> airpipe air conditioning system" /Building and Environment/ 34(2)
>> pp.189-196.
>>
>> ----
>>
>> Denis Bourgeois
>> PhD student/doctorant
>> École d'architecture, Université Laval
>> denis.bourgeois at xxxxxxxxxxxxx <mailto:denis.bourgeois at xxxxxxxxxxxxx>
>>
>> ----
>>
>> ----- Original Message -----
>> *From:* Hugues Boivin <mailto:huguesboivin at xxxxxxxxxxxx>
>> *To:* BLDG-SIM at xxxxxxxx <mailto:BLDG-SIM at xxxxxxxx>
>> *Sent:* Friday, November 21, 2003 1:11 PM
>> *Subject:* [BLDG-SIM] earth-air exchanger (earth channels)
>>
>> Does anyone knows a simulation tool to evaluate energy savings
by
>> earth-to-air exchanger (earth channels) ?
>> Thank you.
>> Hugues Boivin
>> Mechanical Engineer
>> Laval University
>> GRAP (Groupe de recherche en ambiance physique)
>>
>> ==================
>> You received this e-mail because you are subscribed to the
>> BLDG-SIM at xxxxxxxx <mailto:BLDG-SIM at xxxxxxxx> mailing list. To
>> unsubscribe from this mailing list send a blank message to
>> BLDG-SIM-UNSUBSCRIBE at xxxxxxxx
>>
>>
------------------------------------------------------------------------
>> Best Jokes, Best Friends, Best Food. Get all this and more on Best
of
>> Yahoo! Groups.
>>
<http://in.rd.yahoo.com/tagline_groups_11/*http://in.promos.yahoo.com/groups/bestofyahoo/>
>>
>>
------------------------------------------------------------------------
>>
>> _______________________________________________
>> Bldg-sim mailing list
>> http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org
>> To unsubscribe from this mailing list send a blank message to
>> BLDG-SIM-UNSUBSCRIBE at ONEBUILDING.ORG
>>
>>
------------------------------------------------------------------------
>>
>> No virus found in this incoming message.
>> Checked by AVG. Version: 7.5.524 / Virus Database: 270.4.1/1512 -
>> Release Date: 6/21/2008 9:27 AM
>>
>
>
>
Unlimited freedom, unlimited storage. Get it now, on http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/
More information about the Bldg-sim
mailing list