[BLDG-SIM] Simulation on Thermal Energy Storage using DOE2.2

[Andrew S. LAU]

On the energy savings potential of TES.  I do recall that with TES, there 
is an opportunity to save significantly on fan power if the AHU's are 
designed to take advantage of the colder supply air temperatures possible 
with certain types of TES systems.  There is also first cost savings from 
smaller fans and ducts.

Andy Lau, 7group


At 02:59 PM 11/26/2004 -0500, mbusman at noresco.com wrote:
>The last TES I did was for a military base.  I think the base energy manager
>must have gone to a seminar and picked up the buzz word, because he wanted
>TES.  We tried to talk them out of it and just go with a new water-cooled
>central chilled water plant to replace about 10 rotten air-cooled chillers.
>We explained that TES requires the right combination of factors, including
>high demand charge, high peak hour time of use kWh charge, low off peak TOU
>kWh charge, and quite often a utility company or state rebate for demand
>reduction programs to make the project economically viable.  Well they
>wanted their TES and wanted ice storage versus chilled water storage.
>Fortunately, as this was a super ESPC project, the customer was able to kick
>in a few $$ to cover the incremental cost of the ice tanks and associated
>equipment and the rest of the project funded as an energy savings perforance
>contract.  Fortunate, because the electric rates were not conducive to TES.
>Perhaps, the customer saw other value or intangible benefits from the TES.
>
>As expected, between circulating glycol through the chillers and taking the
>performance hit of recharging the ice tanks with an evaporator temperature
>in the 22 deg.F - 26 deg.F range,kWh consumption during ice charging period
>went up.    In the end, though, the difference in kW/ton between the old
>air-cooled recips with corroded condensers and the new electric screw
>chillers measurement and verification (and the few $ of buydown on the TES
>portion) were sufficient and made for a successful project.  One final note
>of interest.  We ran an analysis with and without the TES and as I recall,
>the TES only contributed a couple of $thousand/year in savings with about
>98% of the electric savings coming from the improved kW/ton of the electric
>cooling.
>
>So, don't believe all the buzz words, get the correct rate data and chiller
>part-load data..........and the customer is always right.
>
>Mike Busman
>Senior Project Engineer
>NORESCO, LLC
>
>-----Original Message-----
>From: Chris Jones [mailto:cj at cr-jay.ca]
>Sent: Friday, November 26, 2004 10:23 AM
>To: BLDG-SIM at gard.com
>Subject: [BLDG-SIM] Simulation on Thermal Energy Storage using DOE2.2
>
>
>We did an analysis of an existing building with a large heat/cool storage
>system.  The Owners were very surprised to find out that the building was
>not energy efficient - it just saved on demand charges.  The pumping of
>fluid in and out of the tanks, through heat exchangers occurred 24 hours a
>day significantly increasing the kWh beyond that of a conventional hydronic
>heat/cool building.
>
>At 01:26 11/26/2004, you wrote:
> >Dear Martin,
> >I think the findings may be correct.
> >First, for a TES system the leaving chilled water temperature usually will
> >be lower, so the COP will be deduced, but as the outside temperature is
> >lower, it does not deduced alot.
> >Second, if the TES system using brine water, i think the efficiency will
> >reduce more.
> >As our experience in some project in Hong Kong and Mainland, TES system
> >can only reduce electricity cost due to tariff rate rather than
>consumption.
> >I hope these comment would help.
> >
> >Regards,
> >Ernest Tsang
> >Meinhardt (M&E) Ltd
> >
> >
> >Martin Yip <yipch at emsd.gov.hk> wrote:
> >Dear Bldg-sim Subscribers,<?xml:namespace prefix = o ns =
> >"urn:schemas-microsoft-com:office:office" />
> >
> >I recently simulated an air cooled chiller plant with cold water tank
> >thermal energy storage using DOE 2.2.  I originally expected some energy
> >saving due to improve chiller COP at night charging the storage when
> >compare it with a system without storage.  However, the results showed an
> >energy penalty of a few percentages even though hourly data actually
> >showed COP improvement during charging.  I have already set the loss
> >coefficient to zero for the TES.  I should be most grateful if anyone can
> >comment on this issue and provide some suggestion.
> >
> >Thanks
> >
> >Martin YIP
> >Engineer
> >EMSD, HKSAR
> >
> >
> >
> >
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>
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>Chris Jones
>EnerSys Analytics Inc.
>14 Oneida Avenue
>Toronto, ON M5J-2E3
>Tel. 416 203-7465
>Fax. 416 946-1005
>
>
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Andrew S. Lau, P.E.
7group, www.sevengroup.com
1007 Bayberry Drive
State College, PA  16801
814-238-4273,   FAX 814-863-7229
andylau at psu.edu



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