Agenda - 06-12-2007-4aa - Laserfiche WebLink

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URANGE CULINTY JAIL lEIVAC SYSTEM UPG.RAIDE LIFE CYCLE OUST ANALYSIS INTRODUC'T'ION In an attempt to identify the best replacement system for the Orange County Jail HVAC system the following systems were chosen for further study in this Life Cycle Cost Analysis. This list does NOT indicate any order of preference: ® Four-pipe liydronic system, using constant volume 4-pipe air handling units. T11is scheme. would involve running new hot water piping and chilled water piping where necessary, new chillers and boilers; and new air handling units. ® Water source heat pump units distributed in closets and on mechanical platforms. This system would .involve adding a cooling tower and heat exchanger; replacing existing boilers, running new piping throughout the building; acid installing iiew water source heat pw.izps in the building. ® DX air handling units with hot water heat. This system would require replacing air handling units,: replacing boilers grid hot water piping, and adding DX condensing units on the roof. ~ Geothermal heat pumps. Though it may have been attractive, this option was eliminated .due to the absence of adequate area and the complications associated with installing 15- 20, 450ft deed wells spaced> out on 20ft x 20ft grid spacing. The terrain sturoundirzg the jail is predominately paved areas (streets and parking), adjacent buildings, and grassy areas containing a significant amount of trees. In order to maintain a high level of efficiency, geotlierlnal well'. fields should be located as close to the building as possible to minimize the amount of pumping power rewired. Horizontal trenching gild vertical drilling in the inunediate area of the jail would significantly disrupt. services to this 'building,and the surrounding buildings as well. The grassy area sunounding the Old Courthouse was eliminated because the trenching aiid drilling regtured could destroy the root system. for the'tiees in this area. A.Iso, any piping would' have to be turuieled below the street and would have to be coordinated with any utilities in this area (much are unknown). METHOD OF ANALYSIS Cost estimates for system were performed for each of the systems described above, based on Historical cost. data and RS Means cost estimating manuals. These estimates are for comparison purposes only at this point as the project budget will need to reflect other design elements, prices, arld ,phasing; etc. The building. envelope and load characteristics were modeled using Equest software (DOE-2). Building. use tivas modeled based on 24=Hour occupancy and energy output was compared with actual utility usage obtained from the owner to verify the accuracy of the model.